Effect of Flowable Composite on Fracture Strength of Composite Restored Endodontically Treated Teeth.

Abstract

Background and Objectives: In most instances, it is necessary to restore endodontically treated teeth by a simple method, with low cost in a short time. The purpose of this study was to evaluate the effect of flowable composite in fracture resistance of endodontically treated maxillary premolars restored with composite. Method and Materials: In this in vitro study, 48 sound human maxillary premolars, extracted for orthodontic reasons closed apex, were randomly divided into 3 groups of 16. In groups 2,3 after preparation of the standard access cavity and endodontic treatment, the palatal cusp was reduced to 1.5 mm coronal to the CEJ, leaving the remaining buccal cusp 3mm in buccolingual thickness at the height of contour and similar thickness in CEJ. Samples were prepared as follows: intact (unprepared) teeth(Group 1), composite restoration without flowable composite(Group 2), composite restoration with 2 mm thickness of flowable composite(Group 3). After thermocycling, each tooth was loaded in compression until fracture occured. Data were analyzed with one-way ANOVA and Tukey test. The pattern of fracture was analyzed by Chi-Square test. Results: The mean fracture resistance in groups 1-3 were 689.59  179, 632.86  119 and 583.92  186 (in N) respectively. The differences between groups were not statistically significant (p>0.05). The maximum number of favorable fractures occured in group 1.There were greater number of unfavorable fracture in groups 2 and 3. Conclusion: Composite restoration of endodontically treated maxillary premolars had satisfactory results. Flowable composite had no significant effect on fracture resistance of teeth and did not result in favorable fracture.