Las fracturas radiculares son vistas con más frecuencia en estos días, afectando con mayor frecuencia a los premolares superiores posiblemente por su particular conformación anatómica. También parecen, antaño, haber sido sub diagnosticadas.
Hoy día las fracturas radiculares parecen tener, exceptuando los traumatismos, sólo un par de etiologías: el bruxismo y los pernos intra radiculares. Las publicaciones son abundantes y he debido hacer un resumen de ellas.
Este tema debería merecer nuestra mayor atención.
Dr. Jorge Garat.
J Prosthodont. 2010 Oct;19(7):544-52. doi: 10.1111/j.1532-849X.2010.00636.x. Epub 2010 Aug 16.
Effect of obturating systems, dowel materials, and adhesive luting techniques on the resistance to fracture of endodontically treated teeth.
Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University, Giza, Cairo, Egypt. dr_jul@hotmail.com
Abstract
PURPOSE: The aim of this study was to assess the role of obturating systems, dowel materials, and adhesive techniques on the resistance to fracture of endodontically treated teeth.
MATERIAL AND METHODS: Eighty maxillary central incisors were selected and randomly divided into two groups according to the obturating system (n = 40); group I: gutta-percha and Roeko sealer; group II: RealSeal. Both groups were further subdivided into two subgroups; subgroup A: using ceramic dowels (Cosmopost); subgroup B using fiber dowels (Easy Post). Each subgroup was assigned to two divisions according to the adhesive luting technique; division V (total-etch) Variolink II resin cement; division U (self-adhesive) RelyX Unicem. Composite core build-up was made using a core former. Each specimen was loaded 2 mm from its incisal edge on the palatal side at a 135° angle with the long axis of the tooth using a universal testing machine with a load cell of 5 KN at a crosshead speed of 0.5 mm/min until fracture. Failure loads were recorded in N. Scanning electron microscopic examination at the dentin/resin interface (1000x) was performed. Three-way ANOVA was used to test the effect of obturating system, dowel material, adhesive technique, and their interactions (obturating system * dowel material, obturating system * adhesive, dowel material * adhesive, obturating system * dowel material * adhesive). Duncan’s test was used for pairwise comparison. The significance level was set at p≤ 0.05. Statistical analysis was performed with SPSS 16.0.
RESULTS: The mean resistance to fracture (617.4 N) was statistically significantly higher in the ceramic dowel with gutta-percha and Variolink (GP/C/V) group than in the other groups. The RealSeal and RelyX fiber dowel group’s mean resistance was the lowest and was significantly lower than the other groups.
CONCLUSIONS: In this study, three factors played a part in enhancing the resistance to fracture of endodontically treated teeth. High resistance to fracture was achieved when ceramic dowels were luted with total-etch technique in gutta-percha-obturated teeth.
J Dent. 2010 Nov;38(11):916-20. Epub 2010 Aug 14.
A 10-year retrospective study of the survival rate of teeth restored with metal prefabricated posts versus cast metal posts and cores.
Gómez-Polo M, Llidó B, Rivero A, Del Río J, Celemín A.
Department of Bucofacial Prosthesis, Faculty of Dentistry, University Complutense, Madrid, Spain. mgpolo@odon.um.com
Abstract
OBJECTIVE: The aim of this retrospective study was to compare the cumulative survival rate of teeth restored with prefabricated posts and with cobalt-chrome cast post-cores.
METHODS: 112 endodontically treated teeth restored with prefabricated post and cobalt-chrome cast post-and-cores were evaluated. Teeth were considered as failures when were objective or radiologic sign of endodontic failure, post or root fracture, or when they had been extracted at the moment of the evaluation. Kaplan-Meier’s method was used to reconstruct the survival curves of the restorations and to test the variable type of post-and-core restoration.
RESULTS: 93 of the posts were still in function without clinical or radiographic signs of failure at the time of the examination resulting in a survival rate of 83.03% after a mean follow-up period of 10.08 years. When comparing the two techniques, prefabricated posts showed a slightly higher survival rate: 84.6% versus 82.6%.Focusing on tooth-type, maxillary premolars (n=30) had the highest failure rate (30%) and also the lowest mean lifetime, with 6-and-a-half years. Maxillary incisors (n=20) showed the highest success rate (5%) with only one case of failure.
CONCLUSIONS: The results showed no significant difference between both groups after a 10-year average follow-up.
Endod. 2010 Sep;36(9):1455-8. Epub 2010 Jul 4.
Diagnosis of vertical root fractures in endodontically treated teeth based on clinical and radiographic indices: a systematic review.
Tsesis I, Rosen E, Tamse A, Taschieri S, Kfir A.
Department of Endodontology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. dr.tsesis@gmail.com
Abstract
INTRODUCTION: The diagnosis of vertical root fracture (VRF) is at times complicated for lack of specific signs, symptoms, and/or radiographic features. The purpose of this study was to systematically search and evaluate the literature regarding the diagnostic accuracy of clinical signs and symptoms and radiographic indices for the diagnosis of VRF in endodontically treated teeth by means of a systematic review.
METHODS: An exhaustive literature search combined with strict inclusion and exclusion criteria was undertaken to identify clinical studies that assessed the diagnosis of VRF.
RESULTS: There is no substantial evidence regarding the accuracy of the clinical and radiographic indices for the diagnosis of VRF in endodontically treated teeth.
CONCLUSIONS: Evidence-based data concerning the diagnostic accuracy and clinical effectiveness of clinical and radiographic dental evaluation for the diagnosis of VRF in endodontically treated teeth are lacking. The need for evidence-based research efforts to elucidate the currently unknown situation is of utmost significance.
Int J Periodontics Restorative Dent. 2010 Aug;30(4):393-9.
Crown-root reattachment of a severe subgingival tooth fracture: a 15-month periodontal evaluation.
Giachetti L, Bertini F, Rotundo R.
Department of Dentistry, University of Florence, Florence, Italy. l.giachetti@odonto.unifi.it
Abstract
Traumatic tooth fractures represent an intriguing challenge for clinicians, particularly when they involve the anterior region of the maxilla. In such situations, esthetic, psychosocial, functional, and therapeutic problems may have a negative effect on the patient’s quality of life. In addition, fractures that involve the biologic width of the periodontium are even more difficult to treat. An interdisciplinary approach based on crown lengthening with or without orthodontic extrusion and the definitive prosthetic rehabilitation represent the standard modality of treatment for these conditions to restore the appropriate biologic dimension and to reduce the damage esthetically. However, if the margins of the fragment and the tooth show perfect juxtaposition with no interfragmentary space, an adhesive technique may be indicated. The aim of this case report is to describe the treatment of a severe subgingival tooth fracture by means of adhesive reattachment of the fragment followed by a periodontal evaluation over a 15-month period.
Int Endod J. 2010 May;43(5):436-42.
Fracture resistance of incisor teeth restored using fibre-reinforced posts and threaded metal posts: effect of post length, location, pretreatment and cementation of the final restoration.
Schmitter M, Lippenberger S, Rues S, Gilde H, Rammelsberg P.
Department of Prosthodontics, Section of Material Sciences, University of Heidelberg, Heidelberg, Germany. Marc_Schmitter@med.uni-heidelberg.de
Abstract
OBJECTIVE: The hypothesis of this study was that the fracture load of incisor teeth restored using short, threaded, parallel-sided posts (TMP) is, under special conditions, not inferior to that of teeth restored using long TMPs or fibre-reinforced posts (FRP).
METHODOLOGY: Seventy-two maxillary incisors and 72 mandibular incisors were collected. Sixty-four in each group were root filled; in half of these FRPs were cemented, and in the other half TMPs were used. Half of the FRPs were pretreated; the others were not pretreated. In the TMP-group, half of the teeth received a long post (10 mm), the other half a short post (3 mm). Crowns were fabricated and cemented with Ketac-cem or Panavia. Eight maxillary incisors and eight mandibular incisors with intact natural crowns were used as control groups. All specimens were loaded until fracture.
RESULTS: Fracture loads were higher for pretreated FRPs than for untreated FRPs. If the FRPs were not pretreated, fracture loads for maxillary incisors after use of short metal posts were significantly higher (248 N compared with 133 N, P = 0.027). Fracture loads for teeth restored using long TMPs were not higher than for teeth restored using short TMPs (277 N compared with 266 N). Fracture loads for mandibular incisors restored using long (10 mm) pretreated FRP were higher than for mandibular incisors restored using short (3 mm) metal posts (436 N compared with 285 N). Cementation of the crowns using an adhesive resin cement did not increase the fracture load for mandibular incisors, whereas for maxillary incisors, this cementation technique tended to increase fracture loads in teeth restored with FRP, although this increase was not significant at the P < 0.05 level (P = 0.06). In both groups, fracture loads were higher for mandibular incisors.
CONCLUSIONS: Short, threaded, parallel-sided metal posts might be an alternative to fibre- reinforced posts for maxillary incisors, for teeth with short roots or when FRP cannot be pretreated.
Int Endod J. 2010 May;43(5):424-9.
Vertical fracture resistance of roots after ultrasonic removal of fractured instruments.
Madarati AA, Qualtrough AJ, Watts DC.
School of Dentistry, The University of Manchester, Manchester, UK. ahmad.madarati@hotmail.co.uk
Abstract
AIMS: To investigate ex vivo root resistance to vertical fracture after fractured instruments were ultrasonically removed from different locations in the root canal.
MATERIALS AND METHODS: Fifty-three canine roots were weighed and divided into four groups. Eight roots served as a control group in which canals were instrumented to a size F5-ProTaper instrument. In the experimental groups, F5-ProTaper fragments were fractured in the coronal, middle and apical one-thirds, and then removed ultrasonically. The time required for removal was recorded. Roots were reweighed, and canals were shaped to a size F5-ProTaper and filled with GuttaFlow. After incubation, roots underwent a vertical fracture test in which the force at fracture was recorded. The difference in root mass before and after treatment (fractured file removal or canal preparation) was calculated. Data were analysed using the Kruskal-Wallis, Mann-Whitney post-hoc and regression tests at P < 0.05.
RESULTS: The highest root-mass loss was recorded when fragments were removed from the apical one-third (46.04 mg) followed by the middle and coronal (27.7 and 13.5 mg, respectively); these differences were significant (P < 0.05). There were significant differences in the force required for vertical fracture amongst the experimental groups (P < 0.05) with the lowest mean force recorded in the apical-third group (107.1 N) followed by the middle and coronal (152.6 and 283.3 N, respectively). The highest mean force was recorded in the control group (301.5 N) which was not significantly different from that in the coronal group (P = 1.00). A negative exponential correlation (r = 0.669) existed between the root-mass loss and the force required to fracture the roots.
CONCLUSION: Whilst removal of fractured instruments from the coronal one-third of the root canal can be considered as a safe procedure, removal from deeper locations renders the root less resistant to vertical fracture.
Int Endod J. 2010 May;43(5):356-62.
Fracture resistance of root filled molar teeth restored with glass fibre bundles.
Rodrigues FB, Paranhos MP, Spohr AM, Oshima HM, Carlini B, Burnett LH Jr.
Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Abstract
AIM: To evaluate the effect of unidirectional or woven glass fibre tapes inserted into MOD cavity preparations on the fracture resistance of root filled molar teeth.
METHODOLOGY: Extracted human molar teeth were randomly divided into six groups (n = 15) : G1 – sound teeth, control; G2 – MOD cavity preparation; G3 – MOD + root canal treatment (Endo); G4 – MOD + Endo + composite resin restoration (Resin); G5 – MOD + Endo + unidirectional fibre (UF) + Resin; G6 – MOD + ;Endo + woven fibre (WF) + Resin. The teeth were subjected to a compressive fracture test in a universal testing machine. After testing, two failure modes were classified: pulp chamber floor or cusp.
RESULTS: The highest and the lowest mean fracture strengths were found in sound teeth (G1) (4960N) and MOD + root canal treatment (G3) (612.84N), respectively, with significant differences from the other groups (P < 0.05). The remaining groups had statistically similar means. In G5 and G6, there was a tendency for fracture to occur in the pulp chamber floor compromising tooth integrity.
CONCLUSIONS: The insertion of glass fibres into MOD cavity preparations and restoring them with composite resin was not different than molar teeth filled with composite resin only in terms of fracture resistance. Fibres placed into MOD cavities do not reinforce teeth.
J Endod. 2010 Jun;36(6):1061-3. Epub 2010 Apr 9.
Effect of different intraorifice barriers on the fracture resistance of roots obturated with Resilon or gutta-percha.
Nagas E, Uyanik O, Altundasar E, Durmaz V, Cehreli ZC, Vallittu PK, Lassila LV.
Department of Endodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey. emrenagas@yahoo.com
Abstract
INTRODUCTION: This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon.
METHODS: Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests.
RESULTS: Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P < .05), but not by the type of obturation system used (P > .05).
CONCLUSIONS: The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier.
Dent Traumatol. 2010 Jun;26(3):236-42. Epub 2010 Apr 7.
Crown and crown-root fractures: an evaluation of the treatment plans for management proposed by 154 specialists in restorative dentistry.
de Castro MA, Poi WR, de Castro JC, Panzarini SR, Sonoda CK, Trevisan CL, Luvizuto ER.
Department of Surgery and Integrated Clinics, Araçatuba Dental School, Univ Estadual Paulista (UNESP), Araçatuba, São Paulo, Brazil.
Abstract
Traumatic tooth injuries involve function and aesthetics and cause damage that range from minimal enamel loss to complex fractures involving the pulp tissue and even loss of the tooth crown. Technical knowledge and clinical experience are essential to establish an accurate diagnosis and provide a rational treatment. The purpose of this study was to evaluate the knowledge of Restorative Dentistry specialists about the management of crown and crown-root fractures based on treatment plans proposed by these professionals for these cases. A descriptive questionnaire was mailed to 245 Restorative Dentistry specialists with questions referring to their professional profile and the treatment plans they would propose for the management of crown and crow-root fractures resulting from dental trauma. One hundred and fifty-four questionnaires were returned properly filled. The data were subjected to descriptive statistics and the chi-square test was used to determine the frequency and the level of the significance among the variables. The analysis of data showed that in spite of having a specialist title, all interviewees had great difficulty in planning the treatments. As much as 42.8% of the participants were unable to treat all types of dental trauma. Complicated and uncomplicated crown-root fractures posed the greatest difficulties for the dentists to establish adequate treatment plans because these fractures require multidisciplinary knowledge and approach for a correct case planning and prognosis.
J Prosthet Dent. 2010 Jun;103(6):330-3.
Use of a CAD/CAM-fabricated glass fiber post and core to restore fractured anterior teeth: A clinical report.
Student, Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, People’s Republic of China.
Abstract
Prefabricated glass fiber posts are widely used; however, their shape cannot be changed and they can be unsuitable for severely damaged teeth with wide root canals. This clinical report describes a procedure for restoring a severely damaged anterior tooth with a customized 1-piece glass fiber post and core, fabricated using a CAD/CAM system. This 1-piece glass fiber post and core adapts better to the root canal than a prefabricated glass fiber post, and reduces the cement layer thickness. Furthermore, it does not require the use of a composite resin foundation.
Dent Traumatol. 2010 Apr;26(2):174-81. Epub 2010 Jan 11.
Crown fragment reattachment: report of an extensive case with intra-canal anchorage.
Oliveira GM, Oliveira GB, Ritter AV.
Department of Operative Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, NC 27516-7450, USA.
Abstract
This paper describes the resolution of an extensive complicated crown-root fracture of an endodontically treated maxillary central incisor. Initially, the fractured crown was splinted to the adjacent teeth with orthodontic wire and composite resin. Subsequently, the crown fragment was reattached by means of a fiber post using a hybrid composite resin. Early stage success was achieved with the observance of normality in function, esthetics, and health of the tooth and surrounding periodontal structures. An athletic mouthguard was fabricated to prevent further trauma. Advantages, disadvantages, and prognosis of the treatment presented are discussed.
Dent Mater J. 2010 May;29(3):233-45. Epub 2010 May 13.
Zirconia ceramic post systems: a literature review and a case report.
Ozkurt Z, Işeri U, Kazazoğlu E.
Department of Prosthodontics, Faculty of Dentistry, Yeditepe University, Turkey. zeynepozkurt@hotmail.com
Abstract
Cast metal post-core systems have a long history of successful use because of their superior physical properties. However, their high elastic modulus can cause stress concentrations within the surrounding radicular dentin, resulting in root fractures. Moreover, the increasing demand for more esthetically appealing and biocompatible restorations has led to the development of tooth-colored, translucent, metal-free post-core systems. Notably, prefabricated zirconia ceramic post systems have been introduced to satisfy this trend toward a heightened awareness of esthetics, whereby the translucency of all-ceramic crowns can be successfully maintained with the use of ceramic post-core materials. Owing to the keen interest in and widespread use of zirconia ceramic post systems, many in vitro studies on zirconia posts have been published in the last 15 years. The aim of this article was to present data about the retention, fracture resistance, microleakage, light transmission, esthetic advantages, and radiodensity of zirconia posts. Two clinical survival rate studies were also presented. Based on the results of these studies, zirconia posts have been shown to improve the esthetic quality of all ceramic crowns and thus their usage is recommended. Apart from literature review, a case report in which a fractured fiber post was replaced with a custom-made zirconia post was also presented.
Eur J Prosthodont Restor Dent. 2010 Mar;18(1):23-30.
Fracture resistance of endodontically treated teeth: effect of tooth coloured post material and surface conditioning.
Toman M, Toksavul S, Sarikanat M, Nergiz I, Schmage P.
Department of Prosthetic Dentistry, Faculty of Dentistry, Ege University, Bornova-Izmir, Turkey. tomantr@yahoo.com
Abstract
This in vitro study evaluated the effects of the different endodontic posts and surface conditioning on the fracture resistance and fracture modes of endodontically treated teeth. The experimental groups consisted of zirconia ceramic post with a glasss-ceramic core [A], zirconia ceramic post with a composite core [B], glass fiber composite post (FRC) with a composite core [C], and titanium post with a composite core [D]. All posts in these groups were cemented with self-adhesive resin cement (Rely X Unicem Aplicap) combination with tribochemical silica coating (TSC). Groups E, F, G and H comprised the same post-and-core materials as the first 4 groups but cemented with the same resin cement without TSC. Specimens were subjected to thermal cycling between 5 degrees C and 55 degrees C for a total of 5000 cycles with 30s per cycle. Static load was applied to the palatal surface of each specimen until they were fractured. Statistical analysis was conducted using analysis of variance (ANOVA) followed by post-hoc comparisons (Tukey). The fracture resistance was significantly affected by the post material (P < 0.001) and surface conditioning (P < 0.001; two-way ANOVA). The application of TSC to post surface decreased the fracture resistance of zirconia ceramic post with composite core (p=0.002; Tukey) and glass FRC post with composite core (p=0.029; Tukey). No catastrophic failure was observed for groups B, C, D, E, F and G. Under the testing conditions used, the titanium post/composite core that had been silicoated exhibited the highest fracture resistance.
Eur J Prosthodont Restor Dent. 2010 Mar;18(1):2-7.
Effect of noble metal alloy post and core material on the fracture resistance of endodontically treated teeth.
Toksavul S, Toman M, Sarikanat M, Nergiz I, Schmage P.
Department of Prosthetic Dentistry, Faculty of Dentistry, Ege University, Bornova-Izmir, Turkey. sunatoksavul@yahoo.com
Abstract
The aim of this study was to investigate the effect of one particular brand of post and core system (ER Post) consisted of different post and core materials on the fracture resistance of endodontically treated teeth. Fifty caries-free maxillary central incisors were randomly assigned to five groups (n=10). All teeth were sectioned at the cemento-enamel junction except for the teeth in the control group. Four experimental groups consisted of cast gold post-and-core group (GG), Heraplat post/cast gold core group (HG), titanium post/composite core (TC), and titanium post/cast gold core (TG). The control group (ETT) consisted of endodontically treated teeth without posts. All posts were cemented in the roots with zinc phosphate cement. Following thermal cycling (5000 cycles between 5 degrees C and 55 degrees C with a dwell time of 30 seconds) a static load was applied to 2 mm below the incisal edge on the palatal surface of each specimen until they were fractured. Fracture data obtained and statistically analyzed with one-way ANOVA and a Tukey’s test (p<0.05). Means of the fracture resistance during static loading were: 423.76 N (GG), 529.46 N (HG), 389.08 N (TC), 408.7 N (TG), 404.4 N (ETT, control). Heraplat post with cast gold core exhibited the highest fracture load than the other groups (p<0.05). Specimens in groups HG and ETT (control) showed the most repairable failure. Heraplat post with cast gold core had the highest fracture resistance of endodontically treated teeth.
Am J Dent. 2009 Oct;22(5):311-4.
Optimum post and tooth root diameters for a cast post-core system.
Mou YB, Chen YM, Smales RJ, Yip KH.
Dental Research Institute, Nanjing Medical University, Nanjing, PR China.
Abstract
PURPOSE: To investigate the optimum diameter for the tapered post of a cast alloy post-core system relative to the root diameter, when measured at the root face, that is required to minimize both post and root failures. METHODS: 32 extracted maxillary central incisor teeth were each decoronated perpendicular to the long axis at a point 2.0 mm occlusal to the labial cemento-enamel junction. Following endodontic canal obturation, the teeth were assigned randomly to four equal groups for different diameter tapered post space preparations. Then 1.10, 1.50, 1.70, and 2.00 mm diameter cast Ni-Cr alloy post-cores and complete crowns without ferrules were fabricated. Each root was embedded in a large gypsum stone block and the crown loaded palatally at 135 degrees from the long axis in a universal testing machine at a crosshead speed of 1.0 mm/minute until failure. Results were analyzed using one-way ANOVA with Tukey-Kramer post hoc tests, and Fisher’s exact test, with alpha = 0.05 for statistical significance. RESULTS: Mean failure resistance loads were: 0.60, 0.91, 1.00, and 1.38 kN (P < 0.001). All of the 1.10 mm posts failed, without any root fractures. Conversely, none of the 2.00 mm posts failed, but all of the roots fractured. The optimum post to root diameter ratio to minimize failures was approximately 1:4.
Int Endod J. 2010 Mar;43(3):218-25.
Vertical fracture of root filled teeth restored with posts: the effects of patient age and dentine thickness.
Mireku AS, Romberg E, Fouad AF, Arola D.
Department of Endodontics, Prosthodontics, and Operative Dentistry, Baltimore College of Dental Surgery, University of Maryland, Baltimore, MD 21250, USA.
Abstract
AIM: To determine whether patient age contributed to the fracture resistance of teeth subjected to root canal treatment and post placement. METHODOLOGY: Forty-five single-rooted, single-canal human teeth were mounted, instrumented, obturated and prepared for a post. The teeth were divided into young (18 < or = age < or = 35) and old (60 < or = age) groups and subjected to cyclic loading until fracture; those reaching 200,000 cycles without undergoing failure were then subjected to static loading to fracture. Statistical differences between groups were examined using one-way anovas, and correlations were identified using Pearson’s r; significance was established at P < or = 0.05. RESULTS: There was no significant difference between the two age groups in terms of the number of cycles to fracture (P > 0.05) or the load to fracture (P > 0.05). However, there was a significant correlation (P < or = 0.05) between the root fracture resistance and individual age, indicating that the susceptibility to root fracture increases significantly with increasing patient age. Also, the dentine thickness of roots that fractured was significantly less than those that did not (P = 0.04). CONCLUSION: Vertical root fracture of teeth receiving root canal treatment with posts is more likely to occur in the teeth of older patients (60+) and particularly in those with low dentine thickness.
J Endod. 2010 Feb;36(2):297-301. Epub 2009 Dec 10.
Effect of the number of residual walls on fracture resistances, failure patterns, and photoelasticity of simulated premolars restored with or without fiber-reinforced composite posts.
Nam SH, Chang HS, Min KS, Lee Y, Cho HW, Bae JM.
Department of Conservative Dentistry, Dental College, Wonkwang University, Iksan, Korea.
Abstract
INTRODUCTION: This study compared the fracture resistances and the failure patterns of 100 simulated mandibular premolars of a different number of coronal walls (zero to four walls) with or without fiber-reinforced composite (FRC) posts. In addition, the photoelastic stress distribution was analyzed. METHODS: The fracture resistance was measured at a 45 degrees angle with a crosshead speed of 1mm/min, and the failure patterns were observed. The photoelastic stress distribution of specimens with or without FRC posts was also evaluated. The fracture resistance was analyzed by analysis of variance and a Duncan’s multiple range test (p<0.05). RESULTS: In the no post groups, the fracture resistances decreased significantly in groups with two or fewer walls. The FRC post increased fracture resistances significantly, except for the zero-wall group, and optimized the failure patterns. A high stress concentration was observed along the canal space in the no post groups; stress seemed to be distributed in post groups in photoelasticity. CONCLUSION: Within the limitation of the experimental methods of this study, the FRC post was advantageous in lower premolars, especially with two or more walls in terms of the fracture resistance and stress distribution. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
J Contemp Dent Pract. 2010 Jan 1;11(1):E025-32.
Fracture resistance of teeth obturated with RealSeal using two different chelating agents: an in vitro study.
Al-Kahtani AM, Al-Fawaz H, Al-Sarhan M, Al-Ali K.
Division of Endodontics, Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia. lizg126@yahoo.com
Abstract
OBJECTIVES: The aim of this study was to evaluate the fracture resistance of endodontically treated teeth filled with a resin-based obturation material using two different chelating agents. METHODS AND MATERIALS: Forty extracted single-canal human teeth were prepared, instrumented, and randomly divided into three groups: Group 1 (n=15) received a final flush with 10 ml of neutralized 17% EDTA, followed by 10 ml of sodium hypochlorite (NaOCl), then obturated using lateral condensation with RealSeal. Group 2 (n=15) received a final flush of BioPure MTAD, followed by 10 ml of NaOCl, then obturated using lateral condensation with RealSeal. Group 3, the control group (n=10), was instrumented but not obturated, then the root canal opening was sealed with a temporary filling material. The specimens were stored in 100% humidity for 10 days, mounted in polyester resin, and loaded to failure. RESULTS: The ANOVA revealed a significant difference between the control group and the experimental groups, although there was no statistically significant difference between Group 1 and Group 2 (p=0.05). The MTAD group displayed higher mean fracture load values than the EDTA group. CONCLUSIONS: It can be concluded that filling the root canals with RealSeal increased the in vitro resistance to fracture of single-canal extracted human teeth when compared to instrumented and unobturated teeth. Teeth treated with MTAD demonstrated high fracture-resistance values when compared to teeth treated with 17% EDTA, but they were not statistically significant. CLINICAL SIGNIFICANCE: Filling the root canals with RealSeal with increased bonding to roots will increase resistance to fracture of these teeth.
Braz Dent J. 2009;20(4):297-302.
Influence of intraradicular post and crown ferrule on the fracture strength of endodontically treated teeth.
Pereira JR, Valle AL, Shiratori FK, Ghizoni JS, Melo MP.
Department of Prosthodontics, Dental School, University of Southern Santa Catarina, Tubarão, SC, Brazil. jeffripe@rocketmail.com
Abstract
The aim of this study was to investigate the fracture strength of endodontically treated teeth restored with different posts and variable ferrule heights. Sixty freshly extracted human canines were treated endodontically and randomly assigned to 6 groups (n=10), being restored with custom-made cast post-and-core (CP0 and CP3 groups), prefabricated post and composite resin core (PF0 and PF3 groups), and composite resin (CR0 and CR3 groups). The CP0, PF0 and CR0 groups presented no ferrule and the CP3, PF3 and CR3 presented 3 mm of coronal structure. All teeth were restored with full metal crowns. The fracture strength was measured in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed statistically by 2-way ANOVA and Tukey’s test (alpha=0.05). When the mean fracture strength values were compared (CP0 group – 820.20 N, CP3 group – 1179.12 N; PF0 group – 561.05 N; PF3 group – 906.79 N; CR0 group – 297.84 N; and CR3 group – 1135.15 N) there was statistically significant among the groups (p<0.05), except for the three groups with 3 mm of coronal remaining, which were similar to each other. The results of this study showed that the ferrule in crowns promoted significantly higher fracture strength in the endodontically treated teeth.
Dent Traumatol. 2010 Feb;26(1):47-51.
The effects of digital image enhancement on the detection of vertical root fracture.
Kamburoğlu K, Murat S, Pehlivan SY.
Department of Oral Diagnosis and Radiology, Faculty of Dentistry, Ankara University, Ankara, Turkey. dtkivo@yahoo.com
Abstract
AIM: To determine the effects of digital image enhancement on observer ability to detect experimentally induced vertical root fractures (VRF). MATERIAL AND METHODS: A total of 64 extracted human mandibular premolar teeth were used in this study. In 32 teeth, VRFs were created in the bucco-lingual planes by gently tapping with screw-type root-canal pins. The remaining 32 intact teeth served as a control group. Digital images were obtained using a charge coupled device sensor. Three observers separately examined the original and four types of digitally enhanced images (enhanced using sharpness, zoom-in, reverse-contrast, and pseudo-3D functions) at 1-week intervals. All teeth were evaluated using a 5-point scale for the presence/absence of VRF. Evaluations of each image set were repeated 1 month after the initial viewings. Kappa coefficients were calculated to investigate the degree of intra- and inter-observer agreement. The areas under the receiver operating characteristic (ROC) curves (Az values) were calculated using the MedCalc statistical software. ROC values for each image type, observer and viewing were compared using t-tests. A level of alpha = 0.05 was considered significant. RESULTS: Kappa coefficients for intra-observer agreement ranged from 0.304 to 0.679. Inter-observer agreement kappa values ranged from 0.109 to 0.399 for the first reading and from 0.106 to 0.380 for the second reading. Statistical comparisons between Az values for each observer showed no significant differences (P > 0.05) among image types. CONCLUSION: There were no differences in diagnostic outcomes among differently enhanced images in the in vitro detection of VRF.
J Endod. 2010 Jan;36(1):126-9.
Comparison of five cone beam computed tomography systems for the detection of vertical root fractures.
Hassan B, Metska ME, Ozok AR, van der Stelt P, Wesselink PR.
Department of Oral and Maxillofacial Radiology, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands.
Abstract
INTRODUCTION: This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth (premolar/molar) on detection accuracy. METHODS: Eighty endodontically prepared teeth were divided into four groups and placed in dry mandibles. The teeth in groups Fr-F and Fr-NF were artificially fractured; those in groups control-F and control-NF were not. Groups Fr-F and control-F were root filled. CBCT scans were made using five different commercial CBCT systems. Two observers evaluated images in axial, coronal, and sagittal reconstruction planes. RESULTS: There was a significant difference in detection accuracy among the five systems (p = 0.00001). The presence of RCF did not influence sensitivity (p = 0.16), but it reduced specificity (p = 0.003). Axial slices were significantly more accurate than sagittal and coronal slices (p = 0.0001) in detecting VRF in all systems. Significantly more VRFs were detected among molars than premolars (p = 0.0001). CONCLUSIONS: RCF presence reduced specificity in all systems (p = 0.003) but did not influence accuracy (p = 0.79) except in one system (p = 0.012). Axial slices were the most accurate in detecting VRFs (p = 0.0001).
Dent Traumatol. 2009 Dec;25(6):571-7. Epub 2009 Oct 14.
Comparison of intraoral radiography and limited cone beam computed tomography for the assessment of root-fractured permanent teeth.
Bornstein MM, Wölner-Hanssen AB, Sendi P, von Arx T.
Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland. michael.bornstein@zmk.unibe.ch
AIM: To compare intraoral occlusal (OC) and periapical (PA) radiographs vs. limited cone beam computed tomography (CBCT) in diagnosing root-fractured permanent teeth. MATERIAL AND METHODS: In 38 patients (mean age 24 years, range 8-52 years) with 44 permanent teeth with horizontal root fractures, intraoral radiographs (PA and OC) and limited CBCT were used to evaluate the location (apical, middle, cervical third of the root) and angulation of the fracture line. Furthermore, the conventional radiographs and CBCT images were compared for concordance of fracture location. RESULTS: In the PA and OC radiographs, 28 fractures (63.6%) were located in the middle third of the root, 11 (25.0%) in the apical third and 5 (11.4%) in the cervical third. The PA/OC radiographs and the sagittal CBCT images (facial aspect) yielded the same level of root fracture in 70.5% of cases (31 teeth; 95% CI: 54.1-82.7%). The PA/OC radiographs and sagittal CBCT images (palatal aspect) showed the same level of root fracture in 31.8% of cases. There was a statistically significant association between the angle at which the root fracture line intersected the axis of the tooth and the level of root fracture in the facial aspect of the sagittal CBCT images. CONCLUSIONS: The diagnosis of the location and angulation of root fractures based on limited CBCT imaging differs significantly from diagnostic procedures based on intraoral radiographs (PA/OC) alone. The clinical significance for treatment strategies and for the prognosis of root-fractured teeth has to be addressed in future studies.
Quintessence Int. 2009 Sep;40(8):663-81.
Closing the gap between oral hygiene and minimally invasive dentistry: a review on the resin infiltration technique of incipient (proximal) enamel lesions.
Kielbassa AM, Muller J, Gernhardt CR.
Dental caries on (proximal) tooth surfaces is still a problem in many industrialized countries. The objectives of this review were to present the scientific basis and the principles of the resin infiltration concept, to discuss the inherent clinical applications, and to describe how these backgrounds can be integrated into the concept of minimal intervention dentistry. Data were identified by searches of the Cochrane Registers, Medline, and Scopus. Articles published in English and German through December 2008 were selected, and most up-to-date or relevant references were chosen. Cross-referencing of significant articles identified additionally relevant articles written in other languages and those of historical value. A total of 23 in vitro studies (focusing on penetration depths or demineralization prevention) were found, and 3 clinical studies (involving 122 subjects) could be retrieved; these studies were not comparable. With an increased understanding of the caries process, it is now recognized that demineralized but noncavitated enamel lesions can be arrested or remineralized in many situations. The clinical research evidence on the resin infiltration technique currently is of moderate extent to reach any decisive conclusions; however, based on available laboratory and clinical studies, it seems convincing that resin infiltration of enamel lesions should reduce (or even stop) the progress of white spot lesions. Combining this ultraconservative restorative approach (which is considered microinvasive) with a substantial caries remineralization program may provide therapeutic benefits and significantly reduce both long-term restorative needs and costs, thus complementing the concept of minimal intervention dentistry.
OBJECTIVE: To investigate the role of dentinal tubules in the fracture properties of human root dentin and whether resin-filled dentinal tubules can enhance fracture resistance. MATERIALS AND METHODS: Crack propagation in human root dentin was investigated in 200 microm thick longitudinal samples and examined by light and scanning electron microscopy. 30 maxillary premolar teeth were prepared for work of fracture (Wf) test at different tubule orientations, one perpendicular and two parallel to dentinal tubules. Another 40 single canal premolars were randomly divided into four groups of 10 each: intact dentin, prepared but unobturated canal, canal obturated with epoxy rein (AH Plus/gutta percha), or with UDMA resin sealer (Resilon/RealSeal. The samples were prepared for Wf test parallel to dentinal tubules. Wf was compared under ANOVA with statistical significance set at p<0.05. RESULTS: Dentinal tubules influenced the path of cracks through dentin, with micro-cracks initiated in peritubular dentin of individual tubules ahead of the main crack tip. A significant difference (p<0.001) was found between Wf perpendicular to tubule direction (254.9 J/m(2)) vs. parallel to tubule direction from inner to outer dentin (479.4 J/m(2)). Neither canal preparation nor obturation using epoxy- or UDMA-based resins as sealer cements substantially influenced fracture properties of root dentin, despite extensive infiltration of dentinal tubules by both sealer cements.
Dent Traumatol. 2009 Jun;25(3):248-55.
Rigidity of commonly used dental trauma splints.
Berthold C, Thaler A, Petschelt A.
Friedrich-Alexander-University, Dental Clinic 1 – Operative Dentistry and Periodontology, Erlangen, Germany. berthold@dent.uni-erlangen.de
BACKGROUND/AIMS: The stability of immobilization devices varies from flexible to rigid, depending on the trauma. We evaluated the rigidity of various commonly used splints in vitro MATERIAL AND METHODS: An acrylic resin model was used. The central incisors simulated injured teeth, with increased vertical and horizontal mobility. The lateral incisors and canines stimulated uninjured teeth. Tooth mobility was measured with the Periotest device. Vertical and horizontal measurements were made before and after splinting, and the difference between values was defined as the splint effect. We evaluated 4 composite splints, 3 wire-composite splints, a titanium trauma splint, a titanium ring splint, a bracket splint, and 2 Schuchardt splints RESULTS: For all injured teeth and all splints, there was a significant splint effect for the vertical and horizontal dimensions (P < 0.05). For injured teeth, the composite splints produced the largest changes in vertical tooth mobility; wire-composite splints 1 and 2, using orthodontic wires, produced the smallest vertical splint effects. For uninjured teeth, the Schuchardt 1 splint and the bracket splint produced the largest splint effects; wire-composite splints 1 and 2 produced only a slight change in tooth mobility. Composite splints 2 and 3 produced the largest horizontal splint effects for injured teeth, and the 4 composite splints produced the largest horizontal splint effects for uninjured teeth. The most horizontally flexible splints were the titanium trauma splint and wire-composite splints 1 and 2. CONCLUSIONS: According to the current guidelines and within the limits of an in vitro study, it can be stated that flexible or semirigid splints such as the titanium trauma splint and wire-composite splints 1 and 2 are appropriate for splinting teeth with dislocation injuries and root fractures, whereas rigid splints such as wire-composite splint 3 and the titanium ring splint can be used to treat alveolar process fractures.
Int Endod J. 2009 Aug;42(8):740-53. Epub 2009 Jun 22.
Complicated crown fractures – management and treatment options.
Department of Conservative Dentistry and Endodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India. drvivekaggarwal@gmail.com
AIM: Complicated crown fractures involve enamel, dentine and the pulp. The incidence of complicated crown fractures ranges from 2% to 13% of all dental injuries and the most commonly involved tooth is the maxillary central incisor. Various treatment modalities are available depending upon the clinical, physiological and radiographic status of the involved tooth. The aim of this article was to discuss techniques for the management of complicated crown fractures. SUMMARY: Management of complicated crown fractures depends upon several factors with the result that various clinical modalities have been suggested. Seven case reports of complicated crown fractures are presented and risks/benefits of the treatment plans are discussed. KEY LEARNING POINTS: Proper diagnosis, treatment planning and follow-up care are important factors in the prognosis of complicated crown fractures. Thorough understanding of the available treatment modalities and their specific indications is critical. The risks and benefits of each treatment option should be carefully evaluated during the treatment planning process.
J Dent. 2009 Sep;37(9):652-7. Epub 2009 May 29.
The restoration of permanent immature anterior teeth, root filled using MTA: a review.
Department of Oral Rehabilitation, University of Otago, School of Dentistry, Dunedin, New Zealand.
OBJECTIVES: Immature anterior teeth are at high risk of root fracture following root canal treatment. The literature was explored to determine the current status for post-endodontic restorative management of these teeth. DATA AND SOURCES: The authors explored multiple search engine databases to November 2008. Experiments included in the review involved simulated human or animal immature teeth with mineral trioxide aggregate as an apical plug. The experiments were designed to assess and compare the fracture strength of teeth restored with various materials. Studies that did not fulfil inclusion criteria were omitted from the review. STUDY SELECTION: Four in vitro studies fulfilled selection criteria and were systematically reviewed. All studies differed in sources of teeth, their simulated immature tooth model and mode of force application. CLINICAL IMPLICATIONS: Current evidence, mostly from laboratory studies, suggests the use of composite resin materials placed deep into the coronal aspect of the root canal to impart superior fracture resistance. Further clinical research is needed to assess other reinforcing materials, which include a variety of post systems and luting agents.
J Endod. 2009 Mar;35(3):413-6.
The effect of three composite fiber insertion techniques on fracture resistance of root-filled teeth.
Oskoee PA, Ajami AA, Navimipour EJ, Oskoee SS, Sadjadi J.
Department of Operative Dentistry, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
The aim of this study was to evaluate the effect of three methods of fiber insertion on fracture resistance of endodontically treated maxillary premolars in vitro. Sixty extracted human maxillary premolars received endodontic treatment followed by mesioocclusodistal (MOD) cavities with 2.5 +/- 0.2 mm thicknesses of buccal and lingual cusps at height of contour. The gingival cavosurface margin was 1.5 mm coronal to the cementoenamel junction (CEJ). Subsequently, the teeth were randomly divided into four groups. In the no-fiber group, the cavities were restored with composite, and in other groups, composite impregnated glass fibers were placed in the gingival, middle, and occlusal third surfaces of the cavities, respectively, and were restored similar to the no-fiber group. Subsequent to thermocycling and exertion of compressive forces, statistical analysis showed that the fracture resistance in the occlusal fiber group was significantly higher than that in other groups (p < 0.0005). In addition, the highest favorable fracture and the lowest cusp detachment rates were observed in the occlusal fiber group.
Oper Dent. 2009 Jan-Feb;34(1):109-13.
Periodontal healing of a horizontal root fracture: a case report with a two-year follow-up.
Department of Periodontology, Westphalian Wilhelm University Muenster, Würzburg, Germany. peterslk@uni-muenster.de
BACKGROUND: For traumatized teeth exhibiting crown-root fractures, there is a growing body of evidence that re-fastening the coronal part may result in successful treatment. However, data on the long-term impact of these bonding procedures on the periodontium are scarce. A case report of a young female patient presenting with an isogingivally- and horizontally-fractured lower incisor with a two-year follow-up is presented. METHODS: The tooth fragment was reattached to the remaining root using an adhesive technique after flap elevation and endodontic therapy. No attempt was made to splint the coronal fragment to the neighboring teeth. RESULTS: Despite the subgingival location of the bonding surface, uneventful periodontal healing was clinically monitored during the observation period. The coronal fragment was retained successfully for a period of more than two years. CONCLUSIONS: Even for tooth fractures below the gingival margin, the combined approach of surgery and adhesive techniques can be used successfully to restore a severely traumatized tooth.
Oper Dent. 2009 Jan-Feb;34(1):93-101.
Influence of oversized dowel space preparation on the bond strengths of FRC posts.
Schmage P, Pfeiffer P, Pinto E, Platzer U, Nergiz I.
School of Dental and Oral Medicine, Department of Restorative and Preventive Dentistry, University of Hamburg, Hamburg, Germany.
This study compared the bond strengths of fiber-reinforced composite (FRC) posts luted into oversized dowel spaces with FRC posts luted into precisely fitting dowel spaces using five different resin cements or build-up composites. The hypotheses examined were that bond strength does not present vast variations according to the width of the gap between the root canal and post and that bond strength increases for FRC posts luted with build-up composites compared with FRC posts luted with resin cements. Dowel space preparations (ER post-restoring system, 12 mm in length) were performed on 100 human anterior teeth up to ISO 90 and ISO 110 of 50 roots each. FRC posts, all ISO size 90, were inserted into the precisely fitting as well as into the oversized dowel spaces (n = 10) using five composite materials (Calibra, Multicore Flow, Rely X Unicem; resin cements and Build-It, Rebilda DC; build-up composites). The manufacturers’ instructions of the composite materials were strictly followed except for Rebilda DC, which was used with Adhese for dentin bonding. Following water storage (37 degrees C, 24 hours) and thermocycling (5000 cycles, 5 degrees C-55 degrees C, 30 seconds) tensile strength testing was performed and fracture modes were assessed using SEM. Data were analyzed statistically (one-way and two-way ANOVA, Bonferroni/Dunn correction, alpha < 0.05). The retentive bond strengths of FRC posts in oversized dowel spaces decreased significantly for all luting composites except for Rebilda DC, compared with the respective groups with precise fitting (p < 0.011). Yet, the bond strengths of RelyX Unicem (454 N +/- 64 N), Build-It (422 N +/- 43 N) and Calibra (408 N +/- 50 N) showed significantly higher values for the precisely fitting posts than Rebilda DC (267 N +/- 54 N). RelyX Unicem revealed significantly higher values than Multicore Flow (296 N +/- 73 N). The bond strengths of FRC posts in oversized dowel spaces varied from 301 N +/- 78 N for Build-It to 152 N +/- 37 N for Calibra. The values of Build-It were significantly higher compared with Calibra, Multicore Flow (180 N +/- 47 N) and Rebilda DC (186 N +/- 52 N), as well as those of RelyX Unicem (256 N +/- 115 N) were significantly higher than Calibra. Fracture modes were shown to be mainly adhesive at the post surface or cohesive for precisely fitting posts and to occur between post and composite except for RelyX Unicem with cohesive fractures for the oversized dowel spaces. The build-up composite Build-It showed superior bond strengths in oversized canals, which were still not as high as those of posts in precisely fitting dowel spaces using common resin cements.
Dent Update. 2008 Dec;35(10):696-9.
Tooth fragment reattachment following crown root fracture: a case report.
DePasquale S, Gatt G, Azzopardi A.
Department of Dental Surgery, Mater Dei Hospital,Tal-Qroqq, Malta.
A 32-year-old man presented with a complicated crown-root fracture of a maxillary lateral incisor. The fracture extended subgingivally, and apical to the alveolar bone crest, invading the biologic width. Flap surgery to expose the fractured root face was performed and the coronal tooth fragment reattached with a dual-cure resin adhesive. Examination six months after treatment revealed periodontal health, good aesthetics and normal function.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 Feb;107(2):e48-52.
Uncomplicated crown fracture, complicated crown-root fracture, and horizontal root fracture simultaneously treated in a patient during emergency visit: a case report.
Rajput A, Ataide I, Fernandes M.
Department of Conservative Dentistry and Endodontics, Goa Dental College and Hospital, Bambolim, Goa, India. akhilraj_24@yahoo.com
Complicated crown fractures are not uncommon in cases of severe trauma or sports related injury. Such patients report with pain because of exposed pulp and need emergency care. Because of impaired function, esthetics, and phonetics, such patients are quite apprehensive during their emergency visit. Successful pain management with immediate restoration of function, esthetics, and phonetics should be the prime objective when handling such cases. This article describes immediate treatment of oblique crown root fracture of maxillary left central incisor, horizontal root fracture of maxillary left lateral incisor, and uncomplicated crown fracture of maxillary right central incisor. Maxillary left central incisor was treated with reattachment procedure using light-transmitting fiber post (D.T. Light Post; Bisco, Schaumburg, IL, USA); maxillary left lateral incisor subsequently healed after splinting for 7 weeks, and direct composite build-up was done on maxillary right central incisor. After 2 years, the reattached fragment had satisfying esthetics and excellent function and pulp was still vital in maxillary left lateral incisor and maxillary right central incisor. Various treatment modalities for traumatically injured incisors are shown in this article.
Int Endod J. 2009 Jan;42(1):47-53.
Influence of post fit and post length on fracture resistance.
Büttel L, Krastl G, Lorch H, Naumann M, Zitzmann NU, Weiger R.
Department of Periodontology, Endodontology and Cariology, School of Dentistry, University of Basel, Basel, Switzerland. leonard.Buettel@unibas.ch
AIM: To investigate (i) the impact of post fit (form-congruence) and (ii) the influence of post length on the fracture resistance of severely damaged root filled extracted teeth. METHODOLOGY: Ninety-six single-rooted human teeth were root filled and divided into four groups (n = 24 per group). Post spaces were prepared with a depth of 6 mm (group 1, 3) and 3 mm (group 2, 4). Form-congruence with a maximal fit of the post within the root canal space was obtained in groups 1 and 2, whereas there was no form-congruence in groups 3 and 4. In all groups, glass fibre reinforced composite (FRC) posts were adhesively cemented and direct composite crown build-ups were fabricated without a ferrule. After thermo-mechanical loading (1200000x, 5-50 degrees C), static load was applied until failure. Loads-to-failure [in N] were compared amongst the groups. RESULTS: Post fit did not have a significant influence on fracture resistance, irrespective of the post length. Both groups with post insertion depths of 6 mm resulted in significantly higher mean failure loads (group 1, 394 N; group 3, 408 N) than the groups with post space preparation of 3 mm (group 2, 275 N; group 4, 237 N). CONCLUSIONS: Within the limitations of this study, the fracture resistance of teeth restored with FRC posts and direct resin composite crowns without ferrules was not influenced by post fit within the root canal. These results imply that excessive post space preparation aimed at producing an optimal circumferential post fit is not required to improve fracture resistance of roots.
Fracture resistance of weakened roots restored with composite resin and glass fiber post.
Zogheib LV, Pereira JR, do Valle AL, de Oliveira JA, Pegoraro LF.
Department of Prosthodontics, Dental School of São José dos Campos, State University of São Paulo, São Jose dos Campos, SP, Brazil.
This study evaluated the fracture resistance of weakened roots restored with glass fiber posts, composite resin cores and complete metal crowns. Thirty maxillary canines were randomly divided into 3 groups of 10 teeth each: teeth without weakened roots (control); teeth with partially weakened roots (PWR) and teeth with and largely weakened roots (LWR). The control group was restored with glass fiber posts and a composite resin core. Teeth in the PWR and LWR groups were flared internally to standardized dimensions in order to simulate root weakness. Thereafter, the roots were partially filled with composite resin and restored in the same way as in the control group. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by one-way ANOVA and Dunnett’s test for multiple comparisons (p=0.05). There were statistically significant difference differences (p<0.01) among the groups (control group = 566.73 N; PWR = 409.64 N; and LWR = 410.91 N), with significantly higher fracture strength for the control group. There was no statistically significant difference (p>0.05) between the weakened groups. The results of this study showed that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth.
Gen Dent. 2009 Jan-Feb;57(1):18-26; quiz 27-8, 95-6.
A rationale for the use of high-powered magnification or microscopes in general dentistry.
This article argues that high-powered magnification (4x-6x or more) provides substantially more visual information for diagnosing and treating dental pathology compared to the use of unaided vision or entry-level 2.5x magnification. In all phases of general dentistry, the increased visual detail provided by high magnification reduces ambiguity in diagnosis and treatment decision-making, increases control in treatment implementation, allows a dentist to produce more ergonomic restorations that are less prone to recurrent decay, and arguably improves clinical outcomes compared to work performed with unaidec vision. High magnification enhances a dentist’s ability to diagnose caries and cracks in teeth, distinguish between different colors intraorally, detect the interfaces between different surfaces and materials, detect microscopic interferences in fixed and removable metal frameworks, adjust occlusal prematurities, and polish restorations. This article explains specific general dental applications for high-powered magnification in restorative dentistry, fixed and removable prosthodontics, endodontics, pediatric dentistry, periodontics, and oral surgery.
Quintessence Int. 2008 Sep;39(8):e183-7.
Effect of remaining coronal structure on the resistance to fracture of crowned endodontically treated maxillary first premolars.
Nissan J, Barnea E, Bar Hen D, Assif D.
Department of Oral Rehabilitation, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
OBJECTIVE: Endodontically treated maxillary first premolars present a restorative challenge. The objective of the present study was to assess the resistance to fracture of crowned endodontically treated maxillary first premolars under simulated occlusal load, while preserving various degrees of remaining coronal structure. METHODS AND MATERIALS: The study consisted of 50 intact maxillary first premolars with bifurcated roots and similar root diameter and length, randomly divided into 5 equal experimental groups. All dowels were luted with Flexi-Flow titanium-reinforced composite resin cement. TiCore titanium-reinforced composite resin was used to fabricate the core. Complete cast crowns were fabricated and cemented with zinc phosphate cement. Forces at fracture and mode of failure were recorded. RESULTS: Statistically significant differences (P < .05) were found among mean failure forces for all tested groups in their resistance to fracture under load with the Kruskal-Wallias test and among all combinations of the 5 groups (Z = -1.56/-2.34; P > .05) with the Mann-Whitney test. This indicates that crowned maxillary first premolars with varying degrees of remaining coronal structure differ significantly in their resistance to fracture under occlusal load. There was increased protection against fracture under occlusal loads with more remaining tooth structure. CONCLUSIONS: Within the limitations of this study, remaining coronal structure influenced the fracture resistance of crowned endodontically treated maxillary first premolars. Preservation of tooth structure is important for its protection against fracture under occlusal loads and may influence the tooth prognosis.
Quintessence Int. 2008 Sep;39(8):e179-82.
Effect of reduced post length on the resistance to fracture of crowned, endodontically treated teeth.
Nissan J, Barnea E, Carmon D, Gross M, Assif D.
Department of Prosthetic Dentistry, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
OBJECTIVE: To examine the influence of a reduced post length sealed with a titanium-reinforced composite luting agent on the fracture resistance of crowned endodontically treated teeth with a 2-mm ferrule on healthy tooth structure. METHOD AND MATERIALS: The study consisted of 60 intact single-rooted premolars with similar root diameters and lengths. Teeth were endodontically treated and randomly divided into 6 experimental groups (n = 10) with various post lengths (5, 8, and 10 mm) and types (ParaPost and Dentatus) of equal diameter. Posts were luted with a titanium-reinforced composite resin luting agent. Titanium-reinforced composite resin cores were constructed, and cast crowns with a 2-mm ferrule on healthy tooth structure were cemented. Specimens were mounted in a jig that allowed loading of the buccal cusp in the axio-occlusal line at a 30-degree angle to the long tooth axis. A continuous compressive force at a crosshead speed of 2 mm/min was applied by an Instron testing machine. Forces at fracture (in newtons) and mode of failure were recorded. One-way analysis of variance (ANOVA) and the Scheffe test were used to statistically compare the differences among groups at a significance of 5%. RESULTS: ANOVA showed no statistically significant differences among the mean failure forces for the tested groups in their resistance to fracture under load. The Scheffé contrast test showed no statistically significant differences among all combinations of the 6 tested groups (F [5.59] = 0.032; P > .05). CONCLUSION: Within the limitations of this study, post length did not influence the fracture resistance of crowned endodontically treated teeth with a 2-mm ferrule on healthy tooth structure. For tooth resistance, prosthesis design is more important than post characteristics.
J Endod. 2009 Jan;35(1):117-20. Epub 2008 Nov 8.
Vertical root fracture in upper premolars with endodontic posts: finite element analysis.
Santos AF, Tanaka CB, Lima RG, Espósito CO, Ballester RY, Braga RR, Meira JB.
Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, Brazil.
Upper premolars restored with endodontic posts present a high incidence of vertical root fracture (VRF). Two hypotheses were tested: (1) the smaller mesiodistal diameter favors stress concentration in the root and (2) the lack of an effective bonding between root and post increases the risk of VRF. Using finite element analysis, maximum principal stress was analyzed in 3-dimensional intact upper second premolar models. From the intact models, new models were built including endodontic posts of different elastic modulus (E = 37 or E = 200 GPa) with circular or oval cross-section, either bonded or nonbonded to circular or oval cross-section root canals. The first hypothesis was partially confirmed because the conditions involving nonbonded, low-modulus posts showed lower tensile stress for oval canals compared to circular canals. Tensile stress peaks for the nonbonded models were approximately three times higher than for the bonded or intact models, therefore confirming the second hypothesis.
Fracture resistance of teeth restored with different post systems using new-generation adhesives.
Department of Operative Dentistry and Endodontics at the Faculty of Dentistry, University of Gazi, Ankara, Turkey. bagdagul@gazi.edu.tr
AIM: The aim of this study was to investigate the fracture strength of three post systems cemented with a dual cure composite resin luting cement by using different adhesive systems. METHODS AND MATERIALS: In this study 63 extracted anterior teeth with single roots were endodontically prepared and filled. Teeth were randomly assigned to one of three post systems placed into the prepared canals: Group I – titanium posts (n=21) (Filpost); Group II – glass fiber posts (n=21) (Mirafit White); and Group III zirconia posts (n=21) (CosmoPost). Each group was again randomly divided into three subgroups according to the bonding materials used [Single Bond (n=7), Clearfil SE Bond (n=7), and Prompt L Pop (n=7)]. A dual cured resin cement (Rely X ARC) was used for bonding the posts into the root canals. Standard cores were made by a composite resin (Clearfil Photocore) using core build-ups. The samples were tested in the compression test machine for 1 mm/min and fracture resistance of the teeth were recorded. The data was analyzed by using two-way analysis of variance (ANOVA) and Duncan’s New Multiple Range Tests. A significance level of p<.05 was used for all comparisons. RESULTS: There was a significant difference in fracture resistance between the post systems (p<0.05) and the interaction of adhesive resins and post systems (p<0.05). Mirafit White was more resistant to fracture than other groups; Filpost showed the least resistance to fracture. CosmoPost post system bonded with Single Bond recorded the lowest fracture resistance (p<0.05). CONCLUSION: Endodontically treated anterior teeth restored with glass fiber posts exhibited higher failure loads than teeth restored with zirconia and titanium posts. Self-etching adhesives are better alternatives to etch-and-rinse adhesive systems for luting post systems. CLINICAL SIGNIFICANCE: Under the condition of this study, glass fiber posts are preferable to restore endodontically treated anterior teeth.
Br Dent J. 2008 Dec 13;205(11):E23. Epub 2008 Nov 21.
A comparison of the survival of fibre posts cemented with two different composite resin systems.
Department of Primary Dental Care, King’s College London Dental Institute at Guy’s, King’s College & St. Thomas’ Hospitals, Caldecot Road, London, SE5 9RW.
OBJECTIVES: To evaluate the outcomes of a fibre post cemented with two different luting agents. METHODS: A single type of tooth coloured fibre post (Fibre-White Parapost, Coltene Whaledent) was used along with two different types of luting cement. A total of 129 teeth were treated in this retrospective audit: 79 treated were luted with Calibra Aesthetic Dental Resin Cement (Dentsply) and 50 with Panavia F 2.0 (Kuraray). All teeth were treated by the same operator and had a minimum ferrule of 2 mm and a ParaCore (Coltene Whaledent) composite core placed over the post. Where Calibra Aesthetic Dental Resin Cement was used, all the restorations were undertaken between June 2002 and October 2003 and were reviewed for a period of 38 to 54 months. Where Panavia had been used, all restorations were placed between February 2004 and December 2005 and reviewed for a period of 28 to 50 months. RESULTS: The results for the Calibra cemented posts were: 64 returned for recall and of these 23 were classed as failed. The causes were: root fracture (2), decementation (3), fracture at post-core interface (6), endodontic failure (8) and marginal caries (4). The results for the Panavia cemented posts were: 44 returned for recall and 9 were classed as failed; the causes of failure were fracture at post-core interface (6), endodontic failure (1) and marginal caries (2). CONCLUSIONS: For posts cemented with Calibra, a success rate of 64.1% was determined over a period of 38 to 54 months. The use of Panavia resulted in fewer post failures with a reported success rate of 79.5% over an evaluation period of 28 to 50 months. Mechanical failures by means of fractures occurring anywhere along the length of the post-core complex were the major cause of lack of success. Significantly higher failure rates were observed to occur in partially dentate patients, in those with parafunctional habits and also amongst anterior teeth. While the majority of the mechanical failures were amenable to repair, the latter mode of failure appears to be a major downfall when considering the routine use of fibre resin posts in restorative dentistry. The choice of cement appears to have a significant role in improving prognostic outcome.
Braz Dent J. 2005;16(3):197-201. Epub 2006 Jan 12.
Influence of the remaining coronal structure on the resistance of teeth with intraradicular retainer.
Pereira JR, Neto Tde M, Porto Vde C, Pegoraro LF, do Valle AL.
Department of Prosthodontics, Faculty of Dentistry of Bauru, University of São Paulo, Bauru, SP, Brazil. jeffripe@rocketmail.com
The aim of this study was to compare the resistance of endodontically treated teeth with intraradicular retainer different amounts of remaining coronal structure. Fifty freshly extracted maxillary canines were endodontically treated and randomly assigned to five groups (n=10), as follows: group 1 (control) = teeth with custom cast post and core; group 2 = teeth without remaining coronal structure; group 3, 4 and 5 = teeth with 1 mm, 2 mm and 3 mm of remaining coronal structure, respectively. All specimens in groups 2 to 5 were restored with prefabricated post and resin core. The teeth were embedded in acrylic resin and the fracture strength was measured on a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed statistically by one-way analysis of variance and Tukey’s test. There was no significant differences (p>0.05) between the control group and group 2, and between groups 3, 4 and 5 (p>0.05). Control group and group 2 had significantly higher resistance strength than groups 3, 4 and 5 (p<0.00001). The findings of this study showed that teeth without remaining coronal structure had significantly higher fracture strength than those with remaining coronal structure (1 mm, 2 mm and 3 mm). When the dental crown was not completely removed, the amount of remaining coronal dentin did not significantly affect the fracture strength of endodontically treated teeth with intraradicular retainer.
Dent Traumatol. 2008 Oct;24(5):503-9.
Root fractures in children and adolescents: diagnostic considerations.
Molina JR, Vann WF Jr, McIntyre JD, Trope M, Lee JY.
Department of Pediatric Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27517, USA. julie_molina@dentistry.unc.edu
The objectives of this study were to (i) characterize epidemiologic trends in anterior permanent tooth trauma in a sample of children and adolescents (ii) examine the relationship of crown fractures (CF) and concomitant root fractures (RF) to determine if CFs are protective against RFs and (iii) examine the radiographic evidence of RFs to determine the value of obtaining three vertical periapical radiographic projections. This was an 8-year cross-sectional study of patients aged 6-18 with anterior permanent tooth trauma. We examined cases involving maxillary central/lateral incisors for which three clearly diagnostic periapical radiographs were obtained during the initial emergency visit. Two trained and calibrated dentists served as expert examiners for the radiographic assessments. Kappa statistics were used to determine reliability. Tests for association of concomitant crown and root fractures were performed using Likelihood Ratio Chi-Square tests. The final sample included 185 teeth in 114 children. Our demographic and epidemiologic findings were comparable to those of previous studies. Experts reached this consensus: 22 RFs were detected, 9.6% (eight out of 83) teeth exhibited root fractures when no CFs was documented, and 13.7% (14 out of 102) teeth had both CFs and RFs as separate entities. Good examiner reliability was reached confirming the presence of RFs (Kappa = 0.81). The association of concomitant RFs and CFs was odds ratio = 1.97 (P = 0.052). CFs were not protective against RFs; indeed, teeth with CFs were twice as likely to have an RF as those without CFs. As the number of radiographic projections increased, RFs were identified more often; however, our data suggest that there is no reason to suspect a complete RF in preteen children unless the root exhibits clinical signs such as luxation or severe mobility. This study provides solid evidence to support obtaining multiple radiographic projections at different vertical angulations to rule out RFs in children and adolescents when RFs are suspected.
Oper Dent. 2008 Sep-Oct;33(5):526-33.
The effect of different restoration techniques on the fracture resistance of endodontically-treated molars.
Cobankara FK, Unlu N, Cetin AR, Ozkan HB.
Department of Endodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey. k.funda@excite.com
AIM: This study compared the fracture resistance of endodontically-treated mandibular molars with mesio-occluso-distal (MOD) cavities restored using different restoration techniques. METHODOLOGY: Sixty sound extracted mandibular molars were randomly assigned to six groups (n=10). Group 1 did not receive any preparation. The teeth in Groups 2-6 received root canal treatment and a MOD cavity preparation. The teeth in Group 2 were kept unrestored. Group 3 was restored conventionally with amalgam. Group 4 was restored with a dentin bonding system (DBS, Clearfil SE Bond) and resin composite (CR) (Clearfil Photoposterior). Group 5 was restored with indirect hybrid ceramic inlay material (Estenia). In Group 6, polyethylene ribbon fiber (Ribbond) was inserted into cavities in a buccal-to-lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens, except for Group 2, were loaded to failure by a chewing simulation device (60,000 cycles x 50 N load, 1.3 Hz frequency) in an artificial environment at 37 degrees C. Each tooth was subjected to compressive loading perpendicular to the occlusal surface at a crosshead speed of 1 mm/minute. The mean loads necessary to fracture were recorded in Newtons and the results were statistically analyzed. RESULTS: The mean fracture values were as follows: Group 1: 2485.3 +/- 193.98a, Group 2: 533.9 +/- 59.4a, Group 3: 1705.8 +/- 135.7a, Group 4: 2033.3 +/- 137.6cd, Group 5: 2121.3 +/- 156.5d, Group 6: 1908.9 +/- 132.2cd. There were statistically significant differences between the groups annotated with different letters. Thus, Group 1 (intact teeth) had the greatest fracture resistance and Group 2 (non-restored teeth) the poorest. No statistically significant differences were found between Groups 3 (amalgam), 4 (resin composite) and 6 (polyethylene ribbon fiber reinforced composite) (p > 0.05). Group 5 (indirect hybrid ceramic inlay) had greater fracture resistance than Group 3 (p < 0.05). CONCLUSIONS: Within the limitations of this study, although all of the restoration groups were stronger than the prepared-only group, none of the restoration techniques tested was able to completely restore the fracture resistance lost from MOD cavity preparation. However, use of indirect hybrid inlay restorations in these teeth may be recommended, because this restoration technique indicated more favorable fracture failure modes than other restoration techniques used in this study and particularly greater fracture strength than amalgam restorations. The promising result of indirect hybrid inlay restorations may need to be confirmed by long-term clinical studies.
Dent Mater J. 2008 Jul;27(4):605-11.
Stress distribution in roots restored with different types of post systems with composite resin.
Okada D, Miura H, Suzuki C, Komada W, Shin C, Yamamoto M, Masuoka D.
Fixed Prosthodontics, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan. d.okada.fpro@tmd.ac.jp
Although composite resin core is used with various types of prefabricated posts, it remains unclear which kind of material is most suitable for the post. The aim of this study was to evaluate the influence of prefabricated posts on the stress distribution within the root by finite element analysis. Posts and cores were built up with composite resin and four types of prefabricated posts: two types of glass fiber posts (GFP1, GFP2) with low and high Young’s moduli, a titanium post (TIP), and a stainless steel post (SSP). In all models, stress distribution during function was calculated. There were differences in stress concentration at the root around the end of posts. The magnitudes of stress for GFP1, GFP2, TIP, and STP were 8.7, 9.3, 11.7, and 13.9 MPa respectively. Given the results obtained, GFP1 was the most suitable material for post fabrication since this model showed a lower stress value. It would therefore mean a lower possibility of root fracture.
Dent Mater. 2008 Sep;24(9):1178-86. Epub 2008 Mar 28.
Static and fatigue fracture resistances of pulpless teeth restored with post-cores.
Hayashi M, Sugeta A, Takahashi Y, Imazato S, Ebisu S.
Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan. mikarin@dent.osaka-u.ac.jp
OBJECTIVES: Superior restorative methods for effectively strengthening pulpless teeth need to be identified, since vertical root fractures of pulpless teeth are still a major problem in everyday clinical practice. The present study tested the null hypothesis that there were no differences in static and fatigue fracture resistances of pulpless teeth restored with different types of post-core systems. METHODS: Extracted human premolars were restored with a combination of either a fiber post or metallic post and a composite resin core. Teeth with full crown preparations without post-core restorations served as a control. A 90 degrees vertical or 45 degrees oblique static compressive load was applied to restored teeth, and fracture loads and modes of fracture were recorded. Fatigue fracture tests were conducted by applying sinusoidal cyclic loads to restored teeth from vertical or oblique directions. Fatigue limits for each restoration were calculated using the staircase approach. RESULTS: In both static and fatigue fracture testing under vertical or oblique loadings, the fracture loads of teeth restored with fiber posts were significantly greater than those of teeth restored with metallic posts. The fatigue limits of teeth restored with fiber and metallic posts were 112 kgf and 82 kgf respectively under vertical loadings and 26 kgf and 20 kgf under oblique loadings. SIGNIFICANCE: The combination of a fiber post and a composite resin core showed superior fracture resistance against both static and fatigue loadings compared to restorations using a metallic post, and is therefore recommended in restoring pulpless teeth.
Dent Traumatol. 2008 Aug;24(4):379-87.
Dent Traumatol. 2008 Aug;24(4):377.
Survival of 534 incisors after intra-alveolar root fracture in patients aged 7-17 years.
Cvek M, Tsilingaridis G, Andreasen JO.
Department of Paediatric Dentistry, Eastman Institute, Stockholm, Sweden. miomir.cvek@comhem.se
The purpose of the study was to evaluate and assess the survival rate of 534 root fractured teeth, including factors that may affect the survival rate but were not included in previous long-term studies. Location of fracture was registered as in the cervical, cervical/middle, middle and apical one-third of the root, and root development was categorized into five stages. Altogether, 383 (78%) showed healing of the fracture, with either formation of hard tissue or interposition of soft tissue between the fragments. In these teeth, no significant difference was found between positions in the root or types of healing. In 325 teeth, the healing remained unchanged throughout the control period, while 58 teeth showed a posthealing complication. A new injury occurred in 47 teeth; in 21 of these, the injury healed spontaneously, in four after endodontic treatment. Increased mobility of the coronal fragment was recorded for 32 teeth, and in 11 of these, the looseness of the fragment was so pronounced that the teeth had to be extracted. No healing, i.e. radiolucency in the alveolar bone, adjacent to fracture, took place in 109 teeth (22%). Of these teeth, 34 were extracted during the observation time while 75 (69%) showed healing after endodontic therapy. At the final assessment of survival (including all parameters) of 534 root fractured teeth, 425 (80%) showed survival and 109 (20%) were extracted during the observation period. It was concluded that the survival of root-fractured teeth was high for up to 10 years of observation (mean = 63 months). The highest frequency of tooth loss (70%) was found in 77 teeth with horizontal fractures restricted to the cervical part of the root. When these teeth were excluded, the frequency of survival in remaining teeth rose to 88%.
Dent Traumatol. 2008 Aug;24(4):e1-3. Epub 2008 Jun 28.
Root healing after horizontal fracture: a case report with a 13-year follow up.
Andrade ES, de Campos Sobrinho AL, Andrade MG, Matos JL.
Dentist in Private Practice, Reabilitacões Cirúrgicas Dentofaciais, Salvador, Bahia, Brazil.
Although horizontal root fractures connote a serious trauma to the tooth, they present a favorable prognosis, as the vitality of the pulp remains. Small displacements of the fragments minimize the failure of the healing process; however, even when they occur, the reduction of the diastasis between root fragments is always necessary. A majority of cases are asymptomatic and heal spontaneously even though no therapeutic measures have been adopted. A case of root fracture that was discovered only 1 year after the trauma is presented. Thirteen years later, the tooth is well positioned in the maxillary arch and has kept its pulp vitality despite the obliteration of the root conduct. Expectant management was adopted at the moment of the first examination, and the follow-up of the patient showed it to have been the best choice.
J Dent. 2008 Jul;36(7):513-9. Epub 2008 May 13.
Fracture resistance and failure patterns of endodontically treated mandibular molars with and without glass fiber post in combination with a zirconia-ceramic crown.
Salameh Z, Ounsi HF, Aboushelib MN, Sadig W, Ferrari M.
Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
OBJECTIVE: The aim of this study was to investigate the influence of a fiber post on the fracture mechanics of zirconia crowns inserted over endodontically treated teeth with different extent of coronal damage. METHODS: Endodontically treated human molars with three types of coronal damage received fiber posts before cementation of zirconia-veneered crowns. Controls received composite resin cores without fiber posts. The specimens were loaded to failure and fractographically examined using a scanning electron microscope (SEM). RESULTS: Statistical analysis revealed that specimens with fiber posts demonstrated significantly higher failure loads and favorable fracture pattern compared to the controls. At fractographic analysis, specimens with fiber posts demonstrated delamination of the veneer ceramic from intact zirconia under structure. Meanwhile, the specimens that were restored without a fiber post demonstrated micro-cracking of the composite core build-up resulting in loss of the support under the zirconia crowns which was responsible for the initiation of radial crack and catastrophic damage. CONCLUSIONS: Within the limitation of this study, the insertion of fiber post improved the support under zirconia crowns which resulted in higher fracture loads and favorable failure type compared to composite core build-up.
Twenty-year follow-up of metal-ceramic single crowns: a retrospective study.
Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Oulu, Finland. ritva.napankangas@oulu.fi
PURPOSE: The aim of this clinical retrospective study was to evaluate the survival and success of single metal-ceramic crowns after 20 years. The biologic and technical complications as well as patient satisfaction were recorded. MATERIALS AND METHODS: Fifty patients treated with 100 single metal-ceramic crowns attended the clinical 20-year follow-up examination. The mean follow-up time was 18.8 years (17.5 to 20.5 years). RESULTS: Twenty-one teeth with single crowns were extracted because of root fractures or esthetic or periodontal reasons. Ninety-seven percent of the subjects had no complaints about the esthetics of the crowns. The most common clinical findings were supragingival crown margins caused by gingival recessions, gingival bleeding on probing, and occlusal wear in opposing teeth. The success of the crowns after 20 years was 75%, and the survival was 78%. CONCLUSION: In the 20-year follow-up of single metal-ceramic crowns, there were few biologic and technical complications, and patients were satisfied with the crowns. Crown removal was in most cases the result of root fractures in single crowns with endodontic posts.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008 Aug;106(2):e77-83. Epub 2008 Jun 13.
Fracture resistance of teeth restored with different post systems: in vitro study.
Al-Wahadni AM, Hamdan S, Al-Omiri M, Hammad MM, Hatamleh MM.
Department of Restorative Dentistry, Faculty of Dentistry, Jordan University of Science & Technology, Irbid, Jordan. ahed@just.edu.jo
OBJECTIVES: The objective of this study was to investigate fracture resistance and mode of failure of teeth restored with different prefabricated post systems. STUDY DESIGN: Thirty teeth were collected, sectioned 15 mm from the apex, root canal prepared, and randomly allocated into 3 groups as follows: glass fiber posts (group 1), carbon fiber posts (group 2), and Radix-Anchor titanium posts (group 3). Teeth were then restored with a composite core and tested using a universal testing machine at 10 mm/min cross-head speed. Mode of failure was identified as either reparable or irreparable (catastrophic). RESULTS: Mean values of fracture forces (N) for teeth restored with Radix posts (571.6) were statistically significantly higher than teeth restored with either carbon fiber (420.6) or glass fiber posts (393.9). There were 86.67% of fractures that were catastrophic in nature. CONCLUSIONS: Teeth restored with Radix-titanium posts were more resistant to fracture than those restored with either carbon or glass fiber posts. Most of the fracture modes were catastrophic in nature.
Investigation of stress distribution in roots restored with different crown materials and luting agents.
Suzuki C, Miura H, Okada D, Komada W.
Fixed Prosthodontics, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. c.suzuki.fpro@tmd.ac.jp
The purpose of this study was to identify crown materials and luting agents that would decrease the stress concentrated at the roots of endodontically treated teeth. To this end, natural tooth model (NT), full cast crown model (gold-silver-palladium alloy; MC), polymer-based restorative material crown model (HCC), and all-ceramic crown model (ACC) were constructed. In each model, methyl methacrylate-based resin cement (MMA) and composite cement (CC) were used as luting agents. The magnitudes of von Mises stress of the roots during function were compared. When the luting agent was changed from MMA to CC, von Mises stress in the cervical area decreased by 37.8% for MC, 27.1% for HCC, and 37.0% for ACC. Within the limitations of this study, the combination of HCC and CC gave rise to the lowest stress concentration at the cervical area.
J Dent. 2008 Jun;36(6):444-9. Epub 2008 Apr 21.
The fracture behavior of premolar teeth with class II cavities restored by both direct composite restorations and endodontic post systems.
Nothdurft FP, Seidel E, Gebhart F, Naumann M, Motter PJ, Pospiech PR.
Department of Prosthetic Dentistry and Dental Materials Sciences, Dental School and Clinics, Saarland University, Homburg/Saar, Germany. zmkfnot@uniklinikum-saarland.de
PURPOSE: The aim of the study was to evaluate the influence of different posts on the fracture load and fracture mode of endodontically treated premolars with class II cavities and direct composite restorations in an ex vivo setting. METHODS: Forty-eight single-rooted human premolars were endodontically treated and prepared with standardized MO (mesio-occlusal) cavities. Eight teeth each received either no posts or were restored with titanium screws (BKS), glass fiber posts (DentinPost), or quartz fiber posts (DT Light SL). Sixteen teeth were restored with zirconium dioxide posts (CeraPost). BKS-screws and eight zirconium dioxide posts were cemented conventionally with glass ionomer cement; Panavia F resin cement was used for all others. The specimens were restored with direct composite restorations. Eight sound premolars served as the controls. After thermomechanical fatigue testing, the samples were loaded until fracture occurred at an angle of 45 degrees . All specimens were evaluated for fracture lines. RESULTS: The sound teeth showed the significant highest fracture load (792.50+/-210.01 N). The group restored with quartz fiber posts differed not significantly from the control. In the groups with fiber posts and titanium screws significant higher fracture load values occurred as in the group with direct composite restorations without posts. The groups with fiber posts did not show a more favorable fracture mode than the other groups. CLINICAL SIGNIFICANCE: The use of an intraradicular post in premolars with class II cavities can significantly increase the resistance towards extra-axial forces.
In vitro fracture resistance and deflection of pulpless teeth restored with fiber posts and prepared for veneers.
D’Arcangelo C, De Angelis F, Vadini M, Zazzeroni S, Ciampoli C, D’Amario M.
Department of Restorative Dentistry, School of Dentistry, University G. D’Annunzio-Chieti, Italy. cdarcang@unich.it
The aim of this in vitro study was to evaluate the influence of endodontic therapy, veneer preparation, and their association on fracture resistance and deflection of pulpless anterior teeth and assess whether restoration with quartz fiber-reinforced post can influence these properties. Seventy-five freshly extracted human maxillary central incisors were selected. Teeth were randomly divided into 4 experimental groups (veneer preparation/endodontic therapy/endodontic therapy and veneer preparation/endodontic therapy, veneer preparation, and fiber post placement) and a control group (n = 15). Specimens were loaded to fracture recording crown deflection under load, and data were statistically analyzed. Veneer preparations and endodontic treatment did not significantly influence fracture resistance of maxillary incisors. On the contrary, preparation for veneer significantly increased the deflection values of the specimens. Fiber post restorations seemed to significantly increase mean maximum load values for specimens prepared for veneers. A fiber-reinforced post restoration can be suggested when endodontic treatment is associated with veneer preparation.
Quintessence Int. 2008 Feb;39(2):e58-62.
Fracture resistance of endodontically treated teeth restored with combined composite-amalgam restorations.
Geiger S, Paikin L, Gorfil C, Gordon M.
Department of Restorative Dentistry, The Maurice and Gabriella Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. selgeig@post.tau.ac.il
OBJECTIVE: To evaluate the resistance to fracture of endodontically treated teeth restored with combined composite-amalgam restorations in comparison to all-amalgam restorations. METHOD AND MATERIALS: Forty-eight human premolar teeth were equally divided into 4 groups. Mesio-occlusodistal (MOD) cavities were prepared in 3 groups, and in the fourth group, a modified MOD preparation was designed with an additional buccolingual groove. All teeth were endodontically treated and restored using 1 of several restorative modalities: all amalgam (AM), all amalgam plus dentin adhesive (ADA), amalgam plus dentin adhesive plus composite resin (ADAC), and amalgam plus dentin adhesive plus composite resin with a modified preparation design (ADACM). Specimens were tested in a universal testing machine (Instron). The load (in kilonewtons) at fracture was recorded and statistically analyzed using a Bonferroni one-way statistical analysis (significance: P<or= .01). RESULTS: The teeth restored with a combined composite-amalgam restoration were significantly more resistant to fracture ( P<or= .01) than teeth restored with amalgam alone. The modification with an additional horizontal buccolingual cavity preparation groove did not significantly increase resistance to fracture, nor did the addition of a bonding material to the amalgam restorations. Mean resistance to fracture (in kilonewtons) of each group was as follows: group AM, 0.31; group ADA, 0.34; group ADAC, 0.45; and group ADACM, 0.47. CONCLUSIONS: Restoration of endodontically treated teeth with combined composite-amalgam materials increased tooth resistance to fracture up to 51% when compared to teeth restored with amalgam alone.
J Can Dent Assoc. 2008 Jun;74(5):441.
Fracture resistance of anterior teeth restored with a novel nonmetallic post.
Abo El-Ela OA, Atta OA, El-Mowafy O.
Faculty of dentistry, Suez-Canal University, Ismailia, Egypt.
OBJECTIVE: To determine the fracture resistance of endodontically treated anterior teeth restored with a novel nonmetallic post in combination with self-etching adhesives. MATERIALS AND METHODS: Extracted maxillary anterior teeth were sterilized with gamma irradiation, and each crown was severed 2 mm above the cementoenamel junction. Endodontic treatment was performed, and the teeth were divided into 7 test groups according to the post-adhesive combination used (n = 8 in each group). The following combinations of posts and adhesives were used: group 1, ParaPost stainless steel post with glass ionomer cement (control group); group 2, Light Post post with Clearfil SE Bond bonding agent and Panavia-F adhesive; group 3, Light Post post with Xeno-III bonding agent and Panavia-F adhesive; group 4, ParaPost Fiber White post with Clearfil SE Bond bonding agent and Panavia-F adhesive; group 5, ParaPost Fiber White post with Xeno-III bonding agent and Panavia-F adhesive; group 6, everStick post with Clearfil SE Bond bonding agent and Panavia-F adhesive; and group 7, everStick post with Xeno-III bonding agent and Panavia-F adhesive. Core build-ups to restore anatomic form were made from light-cured composite (TPH3). Specimens were stored in water at 37 degrees C. The roots of each tooth were embedded in an acrylic base, and the teeth were mounted at 135 degrees to the horizontal. The teeth were loaded in an Instron machine, and loading was applied to the point of fracture. Fracture loads were recorded, means and standard deviations (SDs) were calculated, and the data were analyzed with analysis of variance (ANOVA) and Tukey”s tests. RESULTS: The mean fracture load (and SD) for each group was as follows: for group 1, 536.8 (75.1) N; for group 2, 1,000.1 (190.9) N; for group 3, 1,049.9 (231.5) N; for group 4, 1,548.5 (290.0) N; for group 5, 1,171.3 (296.9) N; for group 6, 1,711.7 (516.7) N; and for group 7, 1,825.7 (527.3) N. ANOVA revealed significant differences among the groups (p < 0.001). In addition, the mean fracture value for group 7 was significantly higher than those of the other groups p < 0.05) except for groups 4 and 6. CONCLUSIONS: Use of a novel glass fibre post (the everStick post) was associated with the highest mean fracture force for maxillary anterior teeth, regardless of the bonding agent used, whereas the stainless steel post was associated with the lowest mean fracture force.
J Endod. 2008 May;34(5):583-6. Epub 2008 Mar 24.
The root canal bonding of chemical-cured total-etch resin cements.
Hayashi M, Okamura K, Wu H, Takahashi Y, Koytchev EV, Imazato S, Ebisu S.
Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Osaka, Japan. mikarin@dent.osaka-u.ac.jp
Discovering a durable restorative method to reconstruct and reinforce pulpless teeth is a vital key to help prevent root fractures. Complete and firm adhesion of resin cement in root canal dentin using a post is critical to achieve it. The null hypothesis in the present study was that the bond strength of dual-cured and chemical-cured adhesive resin cements to root canal dentin is not affected by their vertical locations in the root canal. In the experiments, extracted human incisors restored with fiber-reinforced posts and adhesive resin cements were subjected to microtensile bond strength testing. Then, the failure modes and the dentin-bonding interfaces were observed. Self-etch and self-adhesive dual-cured resin cements showed frequent pretesting failure despite using a silane coupling agent. Chemical-cured total-etch adhesive material showed stable bonding performances throughout the entire post space and thus has an advantage in post-core restorations.
Int Endod J. 2008 May;41(5):424-30. Epub 2008 Mar 16.
Influence of core material on fracture resistance and marginal adaptation of restored root filled teeth.
Reill MI, Rosentritt M, Naumann M, Handel G.
Department of Prosthetic Dentistry, Regensburg University Medical Centre, Regensburg, Germany. margarete.reill@klinik.uni-regensburg.de
AIM: To investigate ex vivo the influence of direct placement core materials on the fracture strength and marginal adaptation of root filled maxillary central incisors restored with glass fibre-reinforced posts, various core materials and all-ceramic crowns. METHODOLOGY: Forty-eight human maxillary incisors were root filled. Posts were placed and teeth restored with composite cores and crowns (n = 8). Six core materials were examined after thermal cyclic and mechanical loading (TCML). Fracture force was determined under static loading. The marginal adaptation at the interfaces between cement-tooth and cement-crown were categorized as ‘intact margin’ or ‘marginal gap’ using scanning electron microscopy. Statistical analysis was undertaken with the Mann-Whitney U-test (alpha = P < or = 0.05). RESULTS: Median fracture strength varied between 204 N (low viscous experimental core) and 1094 N (Multicore). No difference in fracture resistance was found with varying viscosity of the core material. The layering technique improved the fracture performance (P = 0.059) to a minor degree. Crowns with dedicated core materials (Rebilda 1063 N; Multicore 1094 N) had a significantly higher fracture resistance than crowns with a conventional restorative material (Tetric Ceram 509 N). Significantly poorer marginal adaptation before TCML was found for the layering technique at the tooth-cement interface and for all experimental cores after TCML. At the crown-cement interface significant differences in marginal adaptation could be determined between Multicore-layered core (P = 0.002) and Multicore-Rebilda (P = 0.001) after TCML. CONCLUSIONS: The fracture strength of post and core restorations was dependent on the core material and bonding system. Marginal adaptation was influenced by the method of application of the core material and by TCML.
Dent Traumatol. 2008 Apr;24(2):214-9.
Effect of a new restoration technique on fracture resistance of endodontically treated teeth.
Sengun A, Cobankara FK, Orucoglu H.
Department of Conservative Dentistry, Faculty of Dentistry, Selcuk University, Konya, Turkey. asengun@selcuk.edu.tr
The aim of the study was to investigate the effect of a new fiber-reinforced composite restoration technique on fracture resistance in endodontically treated premolars. Eighty sound extracted human mandibular premolars were assigned to four groups (n = 20). Group 1 did not receive any treatment. In groups 2, 3 and 4, the teeth received root canal treatment and a mesio-occluso-distal cavity preparation. Group 2 was kept unrestored. Group 3 was restored with a dentin bonding system and composite resin. In group 4, a piece of polyethylene ribbon fiber was inserted into the groove in a buccal to lingual direction during the restoration of teeth with dentin bonding system and composite resin. After finishing and polishing, the specimens were stored in 100% humidity at 37 degrees C for 24 h and placed at an angle of 45 degrees to the long axis of the tooth and subjected to compressive loading in a universal testing machine at a crosshead speed of 0.5 mm min(-1). The load necessary to fracture the samples was recorded in Newton (N) and submitted to Kruskal-Wallis anova and Mann-Whitney U-test. The fracture strength of the teeth reinforced with a combination of polyethylene fiber and composite resin were not significantly different than those that were restored with only composite resin (P > 0.05). However, most of the failure modes of the reinforced teeth were limited to the level of the enamel, while the other three groups showed fractures generally at the level of the dentin, cemento-enamel junction or more below (P < 0.05). Therefore, polyethylene ribbon fiber-reinforced composite resin restorations seemed a more reliable restorative technique than traditional composite restorations for extensive cavities.
J Prosthet Dent. 2008 Mar;99(3):225-32.
Fracture resistance of endodontically treated molars restored with extensive composite resin restorations.
Plotino G, Buono L, Grande NM, Lamorgese V, Somma F.
Department of Endodontics, Catholic University of Sacred Heart, Rome, Italy. gplotino@fastwebnet.it
STATEMENT OF PROBLEM: When cuspal coverage is required, there is no evidence that indirect composite resin restorations are superior to direct restorations in terms of biomechanical behavior. PURPOSE: The purpose of this in vitro study was to compare the fracture resistance of cusp-replacing direct and indirect composite resin restorations in endodontically treated molars. MATERIAL AND METHODS: Forty-five human mandibular molars were selected and divided into 3 groups (n=15): DIR specimens, restored with direct composite resin (Estelite Sigma) restorations; IND specimens, restored with indirect composite resin (Estelite Sigma) restorations, and control specimens, which remained intact. Endodontic treatment was performed using NiTi ProTaper rotary instruments, and teeth were filled using lateral condensation of gutta-percha and sealer. Extensive Class II MO cavities were prepared, and the 2 mesial cusps were reduced, allowing a 2-mm layer of composite resin. All teeth were prepared to the same dimensions, considering reasonable human variation. Specimens were loaded to failure and the fracture loads were recorded (N). The mode of fracture was determined using a stereomicroscope and classified as favorable or unfavorable failure. The data were subjected to a Kruskal-Wallis test, multiple-comparison Mann-Whitney test, and a chi-square test (alpha=.05). RESULTS: Significant differences (P<.001) were observed between the control group and both DIR and IND groups. However, no significant difference was found between the DIR and IND groups. The chi-square test did not show a significant difference in the frequencies of favorable/unfavorable failure modes among the 3 groups (P=.981). CONCLUSIONS: No significant difference was observed in the fracture resistance of endodontically treated molars restored to original contours with an extensive cusp-replacing direct or indirect composite resin restoration.
J Dent. 2008 Apr;36(4):287-93. Epub 2008 Feb 21.
Influence of endodontic posts on the fracture behavior of crowned premolars with Class II cavities.
Nothdurft FP, Seidel E, Gebhart F, Naumann M, Motter PJ, Pospiech PR.
Department of Prosthetic Dentistry and Dental Materials Sciences, Dental School and Clinics, Saarland University, Homburg/Saar, Germany. zmkfnot@uniklinikum-saarland.de
AIM: The aim of the study was to evaluate the influence of different posts and types of cementation on the fracture load and fracture mode of crowned, endodontically treated premolars with class II cavities in an ex vivo setting. METHODS: Forty-eight single-rooted human premolars were endodontically treated and prepared with standardized MO (mesio-occlusal) cavities and a circular chamfer preparation. Eight teeth each received either no posts or were restored with screws (BKS), glass fiber posts (DentinPost), or quartz fiber posts (DT Light SL). Sixteen teeth were restored with zirconium dioxide posts (CeraPost). BKS-screws and eight zirconium dioxide posts were cemented conventionally with glass ionomer cement; Panavia F was used for all others. The specimens were restored with composite cores and crowns cast from a non-precious metal. Eight sound premolars served as the controls. After thermomechanical fatigue testing, the samples were loaded until fracture occurred at an angle of 45 degrees. All specimens were evaluated for fracture lines. RESULTS: The sound teeth showed the significant highest fracture load (792.50+/-210.01 N). Conventionally cemented zirconium dioxide posts showed the lowest fracture load (327.00+/-45.84 N); the highest fracture load occurred with quartz fiber posts (421.75+/-90.19 N). Only the difference between these two groups was statistically significant. With glass fiber posts and conventionally cemented zirconia posts, restored teeth failed mostly in an “unfavourable” mode. CONCLUSIONS: With respect to the fracture load, there was no statistical difference between the restoration of non-vital premolars with class II cavities with crowns and posts or crowns alone.
J Contemp Dent Pract. 2008 Jan 1;9(1):30-7.
Fracture resistance of endodontically-treated teeth restored using three root-reinforcement methods.
Moosavi H, Maleknejad F, Kimyai S.
Department of Operative Dentistry of School of Dentistry, Dental Research Center at Mashhad University of Medical Sciences in Mashhad, Iran. moosavih@mums.ac.ir
AIM: The aim of this in vitro study was to compare the fracture resistance of endodontically-treated anterior teeth with their roots reinforced using three different restorative methods. METHODS AND MATERIALS: Forty sound maxillary human central incisors were randomly assigned to four groups (n=10). The crowns of the teeth were removed at a level 2 mm incisal to the cementoenamel junction (CEJ). After root canal therapy, flared canals were simulated in three groups. In the first, second, and third groups the flared canals were reinforced with resin composite (RCO) (Clearfil DC Core Automix), two Reforpins (REF), and a resin cement (RCE) (Panavia F 2.0), respectively. In the fourth (DEN) group flared canals were not created. The same size fiber reinforced composite (FRC) posts were cemented with resin cement (Panavia F 2.0) in all groups. After post cementation and restoration of the teeth crown with a core build-up composite (Clearfil Photo Core), the roots of the teeth were embedded in acrylic resin blocks up to 1 mm below the CEJ. The samples were loaded in an Instron testing machine with a crosshead speed of 0.5 mm/min at a 45 angle to the long axis of the tooth on the palatal surfaces until failure occurred. Data were analyzed using the Kruskal-Wallis, Mann-Whitney, and Chi-square tests (p=0.05). RESULTS: Significant differences were found between fracture resistance in all of the groups (P<0.05) with the exception being among the RCO and REF groups. The least mean value 230 (130) N and the highest mean value 830 (220) N were shown in the fracture resistance of the RCE and DEN groups, respectively. CONCLUSION: Reforpin can be used as an alternative to resin composite for internal reinforcement of weakened roots according to the results of this study. For reinforcement of flared canals, fiber posts along with Reforpin or resin composite proved to have higher fracture resistance than resin cement. Non flared canals had the highest fracture resistance.
J Prosthet Dent. 2007 Oct;98(4):270-6.
Microleakage and fracture patterns of teeth restored with different posts under dynamic loading.
Jung SH, Min KS, Chang HS, Park SD, Kwon SN, Bae JM.
Department of Conservative Dentistry, College of Dentistry, Wonkwang University, Iksan City, Korea.
STATEMENT OF PROBLEM: Many studies concerned with the microleakage of endodontically treated teeth restored with posts and cores and subjected to loading can be found in the literature. However, no studies have investigated microleakage under dynamic loading with simultaneous dye penetration, which is more relevant to clinical situations. PURPOSE: The purpose of this study was to compare microleakage and to classify fracture patterns of endodontically treated teeth restored with various post systems under dynamic loading. MATERIAL AND METHODS: The crown portions of 40 human mandibular incisors were sectioned at the cementoenamel junction, and the teeth were endodontically treated. Teeth were divided into 4 groups (n=10): teeth restored with a cast post and core, prefabricated metal post (ParaPost), fiber-reinforced composite resin post (FRC Postec), and ceramic post (Cosmopost). After preparing the post space, each post was cemented with dual-polymerized resin cement (DuoLink). With the exception of the cast post-and-core group, the cores were formed directly using a light-polymerized composite resin (Light-Core). An intermittent load of 98 N at 1 Hz was applied for 50,000 cycles at an angle of 135 degrees to the long axis of the restored teeth, which were immersed in a 0.5% basic fuchsin solution. The ratio of the dyed surface area to the total area of the sectioned root surface was determined using an image analysis program. The data were analyzed by a 1-way ANOVA and Duncan’s multiple range test (alpha =.05). The fracture patterns of the teeth were classified according to their fracture propagation lines. RESULTS: The cast post group showed a significantly higher level of microleakage compared to the other groups (P=.001). Regarding the failure mode, the FRC Postec and Cosmopost groups showed fracture patterns that would favor retreatment. The number of cycles of repeated loading was not significantly different among the groups (P=.161). CONCLUSIONS: Both FRC Postec and Cosmopost groups showed less microleakage under dynamic loading and fracture patterns favoring a retreatment of fractured specimens.
Oper Dent. 2007 Sep-Oct;32(5):510-4.
In vitro fracture resistance of endodontically-treated maxillary premolars.
Oskoee SS, Oskoee PA, Navimipour EJ, Shahi S.
Department of Operative Dentistry, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran. soskoee@hotmail.com
Many endodontically-treated teeth require quick, simple, low-cost restorations. This study evaluated the effect of horizontal pins and flowable composites on the fracture resistance of endodontically-treated maxillary premolars directly restored with resin composite. In this in vitro study, 64 intact human maxillary premolars, extracted for orthodontic reasons, were randomly divided into four groups of 16. Standard access cavities were prepared in such a way that the buccal cusp had a buccolingual thickness of 3 mm measured at the height of contour. The palatal cusp was reduced to 1.5 mm coronal to CEJ. The specimens were prepared as follows: Group 1: resin composite restoration without horizontal self-threading pins or flowable composite (control group). Group 2: resin composite restoration without horizontal self-threading pins but with a 2 mm thickness of the flowable composite. Group 3: resin composite restoration with two horizontal self-threading pins in the buccal cusp but without flowable composite. Group 4: resin composite restoration with two horizontal self-threading pins in the buccal cusp and flowable composite with a thickness of 2 mm. Subsequent to thermocycling, all specimens were loaded to failure. The data were analyzed using a two-factor ANOVA test (alpha = 0.05). The maximum mean of fracture resistance was in Group 1 (632.86 +/- 119.46 N), and the minimum value was related to Group 3 (533.49 +/- 168.07 N). There was not a statistically significant difference between the groups (p > 0.05). Conclusion: Neither horizontal pin placement nor flowable composite had a significant effect on increasing the fracture resistance of endodontically-treated maxillary premolars restored with composite.
J Prosthet Dent. 2007 Sep;98(3):186-92.
Fracture resistance of thermal cycled and endodontically treated premolars with adhesive restorations.
de V Habekost L, Camacho GB, Azevedo EC, Demarco FF.
Department of Operative Dentistry, RS, Brazil. luvh@bol.com.br
STATEMENT OF PROBLEM: Cavity preparations have routinely been associated with decreased fracture strength of restored teeth. PURPOSE: The purpose of this study was to evaluate the influence of endodontic treatment and thermal cycling on the fracture resistance of teeth restored with ceramic or composite resin inlay restorations. MATERIAL AND METHODS: One hundred sound, maxillary premolars were selected. Twenty intact teeth served as a control group. Eighty teeth were prepared with MOD cavity preparations; half of them were also endodontically treated. Inlay restorations were prepared with composite resin (Filtek Z250) or feldspathic ceramic (Vitadur Alpha). Half of the specimens for each group were submitted to thermal cycling (500 cycles, between 5 and 55 degrees C, dwell time of 30 seconds). The specimens were subjected to compressive axial loading using a steel ball. Data were analyzed using 3-way ANOVA and post hoc Tukey’s test (alpha=.05). RESULTS: Except for those teeth restored with ceramic without endodontic treatment and thermal cycling, no other group achieved fracture strength similar to sound teeth. Ceramic and composite resin restorations provided similar resistance to fracture. There was a significant interaction between endodontic therapy and thermal cycling (P<.001). In the nonthermal cycled groups, endodontically treated teeth showed significantly lower fracture resistance (P<.001). All experimental groups had similar fracture strength when submitted to thermal cycling. CONCLUSIONS: Both restorative techniques provided similar fracture resistance. Endodontic treatment decreased the fracture resistance of nonthermal cycled specimens, while thermal cycling decreased the fracture resistance of nonendodontically treated specimens.
Quintessence Int. 2007 Sep;38(8):e511-6.
A comparison of the fracture resistance of core materials using different types of posts.
Coltak KM, Yaniko?lu ND, Bayindir F.
Department of Endodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
OBJECTIVE: The purpose of this in vitro study was to determine the fracture resistance of 3 core materials (silver amalgam, resin composite, glass-ionomer cement) supported by 1 custom cast post (nickel-chromium alloy) and 2 prefabricated posts (Radix and Safix posts). METHOD AND MATERIALS: A sum of 45 recently extracted single-rooted human incisors and canines were placed in 0.5% sodium hypochlorite. Before the experiments, the anatomic crowns of teeth were removed below the cementoenamel junction to obtain a standard root length. The roots were endodontically treated by the manual condensation method. The teeth were randomly divided into 9 groups with 5 samples per group. The posts were luted in the corresponding root canals with zinc polycarboxylate cement. Each core reconstruction was prepared with diamond instruments, and the height of cores formed was 6.0 mm. The tooth and post-core combinations were mounted in acrylic resin blocks. Each tooth and post-core combination was placed in a special jig at a 45-degree angle to the buccal/lingual axis and then subjected to a load on an electronic pull-tension-compression testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed using one-way analysis of variance. RESULTS: The resistance to fracture for prefabricated posts was significantly higher for resin composite core than for the other post-core combinations (P <.001). For prefabricated posts, the composite core and amalgam core materials were significantly stronger than the glass-ionomer core material (P <.001). The differences between the core materials were statistically significant (P <.001). CONCLUSION: The glass-ionomer core with custom post was the weakest post-core system, while the prefabricated posts (Safix and Radix) with resin composite and amalgam cores were the strongest post-core systems.
Pract Proced Aesthet Dent. 2007 Jul;19(6):359-64; quiz 365.
Restoring teeth with prefabricated fiber-reinforced resin posts.
Perdigão J, Monteiro P, Gomes G, Santos V.
Division of Operative Dentistry, Department of Restorative Sciences, University of Minnesota, Minneapolis, MN, USA. perdi001@umn.edu
The use of fiber-reinforced resin (FRR) posts to restore endodontically treated teeth has gained popularity as an alternative to cast or prefabricated metal posts. This may be due to the two important characteristics of fiber posts: I) their modulus of elasticity, which is similar to that of dentin, and 2) their ability to be adhesively cemented. The following article will discuss these characteristics, clinical indications for FRR posts, as well as increased fracture resistance, adhesion to root dentin, and guidelines for placement. LEARNING OBJECTIVES: This article reviews recent research on prefabricated fiber-reinforced resin (FRR) endodontic posts. Upon completing this article, the reader should: Understand clinical guidelines for the selection and cementation of FRR posts. Realize the importance of fracture resistance to the long-term performance of an endodontically treated tooth.
Quintessence Int. 2007 Jul-Aug;38(7):e364-7.
Effect of endodontic access type on the resistance to fracture of maxillary incisors.
Nissan J, Zukerman O, Rosenfelder S, Barnea E, Shifman A.
Department of Prosthodontics, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. nissandr@post.tau.ac.il <nissandr@post.tau.ac.il>
OBJECTIVE: To compare the effect of endodontic access cavity location–labial versus palatal–on the resistance to fracture of maxillary incisors. METHOD AND MATERIALS: Sixty intact human maxillary incisors were selected: 20 pairs of central incisors and 10 pairs of lateral incisors. From each pair, 1 tooth was randomly selected to receive a palatal access cavity; the other tooth of the same pair received a labial access cavity. The teeth were divided into 4 test groups: group 1, central incisors with labial access; group 2, central incisors with palatal access; group 3, lateral incisors with labial access; and group 4, lateral incisors with palatal access. A lateral condensation technique was used to fill the canals with gutta-percha cones and AH-26 (Dentsply DeTrey). The access cavities were restored with hybrid resin composite. Specimens were mounted in a jig that allowed loading at the center of the palatal surface of the tooth, over the cingulum, at an angle of 130 degrees to the long axis of the tooth. Continuous compressive force at a crosshead speed of 2 mm/min was applied by an Instron universal testing machine. Load at fracture and mode of failure were recorded. Multiple analysis of variance (MANOVA) with repeated measures was used to statistically compare differences between groups at a significance of 5%. RESULTS: Mean failure loads for the 4 test groups were as follows: 894 N (group 1), 821 N (group 2), 774 N (group 3), and 705 N (group 4). No significant difference in failure load values was found among all tested groups (F = 0.5; P >.05). The mode of failure in all groups was an oblique radicular fracture, either at the level of the cementoenamel junction in 40% to 45% or at the root level in 55% to 60% of the teeth. CONCLUSION: Different endodontic accesses-labial or palatal-did not affect the failure resistance of maxillary incisors under simulated occlusal load.
Quintessence Int. 2007 Feb;38(2):e120-3.
Resistance to fracture of crowned endodontically treated premolars restored with ceramic and metal post systems.
Nissan J, Parson A, Barnea E, Shifman A, Assif D.
Department of Prosthodontics, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. nissandr@post.tau.ac.il <nissandr@post.tau.ac.il>
OBJECTIVES: The objective of this study was to assess the resistance to fracture of crowned endodontically treated premolars with varying ceramic and metal post systems under simulated occlusal load. METHOD AND MATERIALS: The study consisted of 60 extracted intact premolars with similar root diameter and length. Teeth were divided equally into 4 groups (n = 15) and prepared for posts and cast crowns as follows: group 1 = preformed metal post, composite core, and cast crown; group 2 = cast post and core and cast crown; group 3 = zirconia post, composite core, and cast crown; and group 4 = zirconia post and heat-pressed ceramic core and cast crown. All prepared teeth had 2 mm of sound dentin on which the cast crowns were cemented. A continuous load (kg) was applied by an Instron testing machine to the buccal cusp at a 30-degree angle to the long axis of each tooth at a crosshead speed of 2 mm/min until failure. One-way analysis of variance with Scheffe test was used to statistically compare the differences between groups. RESULTS: Mean failure loads (in newtons) for the 4 test groups were as follows: 1,103.3 (group 1), 1,234.5 (group 2), 826.6 (group 3), and 870.6 (group 4). No significant difference in failure load values was found among all tested groups (F[3,59] = 2.05; P >.05). The primary mode of failure (85%) in all groups was an oblique radicular fracture, either apical to the post or at the post level. Horizontal fracture (15% to 20%) of the root and post was found in groups 3 and 4. CONCLUSION: Within the limitations of this study, varying ceramic and metal post systems did not affect the failure resistance of teeth restored with full-coverage cast metal crowns, under simulated occlusal load.
J Adhes Dent. 2007 Feb;9(1):49-56.
Effect of post-retained composite restoration of MOD preparations on the fracture resistance of endodontically treated teeth.
Sorrentino R, Salameh Z, Zarone F, Tay FR, Ferrari M.
Department of Dental Materials and Restorative Dentistry, University of Siena, Policlinico Le Scotte, Siena, Italy.
PURPOSE: The present study aimed to compare the fracture resistance and failure patterns of endodontically treated premolars with MOD preparations restored using different material combinations. The null hypothesis postulated that there was no association between the fracture resistance of endodontically treated premolars and the resin composite materials or the post-and-core system used to build up the restorations. MATERIALS AND METHODS: Eighty single-rooted maxillary premolars were used. After endodontic treatment and preparation of MOD preparations, 8 groups of 10 samples each were created, using the following material combinations: group 1 (control), flowable and microhybrid resin composites; group 2, flowable A; group 3, flowable B; group 4, microhybrid resin A; group 5, microhybrid resin B; group 6, flowable B + microhybrid resin B; group 7, flowable A + microhybrid resin A + post A; group 8, flowable B + microhybrid resin B + post B. Mechanical static fracture tests were performed loading the specimens till fracture. RESULTS: The mean failure loads (N) were 502 (control), 470 (group 7), 445 (group 8), 441 (group 6), 405 (group 5), 364 (group 4), 317 (group 2), and 302 (group 3). Statistically significant differences were found between groups 1 vs 2, 1 vs 3, and 3 vs 7 (p < 0.05). CONCLUSION: The fracture resistance of endodontically treated premolars with MOD preparations was enhanced by the use of the sandwich technique. The samples restored with posts predominantly showed restorable fractures, while teeth restored without posts mostly displayed unrestorable failures.
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