COMPARATIVE EVALUATION OF FLEXURAL STRENGTH AND ELASTIC MODULUS OF PROVISIONAL CROWN AND BRIDGE MATERIALS AT DIFFERENT STORAGE INTERVALS.

Abstract

Introduction: Provisional restorations are an integral part of xed prosthesis and dental implantology. They serve as a key role in functional and esthetic tryin for design of nal prosthesis. Fixed prosthesis prognosis depends on the quality of provisional restoration. In long term cases like full mouth rehabilitation and in implant supported prosthesis exural strength (FS) and elastic modulus (EM) of the interim prosthesis play a vital role. Aim: To evaluate and compare the exural strength (FS) and elastic modulus (EM) of provisional crown and bridge materials stored at different time intervals in articial saliva. Materials And Methods: Ninety bar-shaped specimens (with dimensions of 25 × 2 × 2 mm) as per American National Standards Institute (ANSI specication no 27) were fabricated with three provisional restorative materials Polymethyl Methacrylate (PMMA), Bis acrylic, Urethane dimethacrylate (UDMA) and are stored in articial saliva at different time intervals. Further three point bending test were carried out in universal testing machine to calculate FS and EM. Changes were evaluated and data was analysed using one way ANOVA and paired t test. Results: Results showed signicant difference (P<0.05S) in FS values of provisional materials at different storage intervals except PMMA showed non-signicant difference (p>0.05) between 10days to 30days storage. There was non-signicant difference (p>0.05) of EM of bis-acryl samples between 24hrs to 10days and from10days to 30days of storage. Conclusion: Within the limitations of the study, it can be concluded that the FS and EM of Bis acrylic is comparatively better than PMMA and UDMA. Bis acrylic could be a better provisional restorative material for an extended period as less change was observed in elastic modulus of bisacryl during long term storage compared to other materials.