In vitro comparison of flexural strength and elastic modulus of three provisional crown materials used in fixed prosthodontics
نویسندگان
چکیده
OBJECTIVES To evaluate and compare the flexural strength and the elastic moduli of three provisional crown materials (methyl methacrylate based autopolymerized resin, bis acryl composite based autopolymerized resin and urethane dimethacrylate based light polymerized resin) after storing in artificial saliva and testing at intervals of 24 hours and 7 days. STUDY DESIGN A metal master mould with four slots of dimensions 25x2x2 mm was fabricated to obtain samples of standard dimensions. A total of 135 specimens were thus obtained with 45 each of three provisional materials. Further 15 samples of each group were tested after storing for one hour at room temperature and again at intervals of 24 hours and 7 days after storing in artificial saliva. Three point flexural tests were carried out in the universal testing machine to calculate the flexural strength and the elastic modulus. The changes were calculated and data was analyzed with Fisher's test and ANOVA. RESULTS The flexural strength of the methyl methacrylate resin reduced significantly while bis-acrylic composite resin showed a significant increase in its flexural strength after storing in artificial saliva for 24 hours and the values of both remained constant thereafter. Contrary to these findings, light polymerized resin showed a significant decrease in flexural strength after storing in artificial saliva for 24 hours and then significantly increased in flexural strength after 7 days. However the changes in the values for elastic modulus of respective materials were statistically insignificant. CONCLUSION Methacrylate based autopolymerizing resin showed the highest flexural strength and elastic moduli after fabrication and after storing in artificial saliva and for 24 hours and 7 days. Bis-acrylic composite resin showed the least flexural strength and elastic moduli. Key words:Provisional restorations, interim restorations, Methyl Methacrylate, composite restoration, flexural strength, elastic moduli.
منابع مشابه
Comparative Evaluation of the Flexural Strength of Heat Polymerized Acrylic Resin with the Addition of 8% and 13% Aluminum Oxide Powder: An In-vitro Study
Introduction: Acrylic resins have been used successfully as denture bases. However, acrylic resin denture base materials are brittle and have poor strength and thermal conductivity. Therefore, it is essential to improve the flexural strength of heat polymerized acrylic resin. The present study aimed to evaluate and compare the flexural strength of heated polymerized acrylic res...
متن کاملEvaluation of polymethyl methacrylate resin mechanical properties with incorporated halloysite nanotubes
PURPOSE This study inspects the effect of incorporating halloysite nanotubes (HNTs) into polymethyl methacrylate (PMMA) resin on its flexural strength, hardness, and Young's modulus. MATERIALS AND METHODS Four groups of acrylic resin powder were prepared. One group without HNTs was used as a control group and the other three groups contained 0.3, 0.6 and 0.9 wt% HNTs. For each one, flexural s...
متن کاملEvaluation of Soldered Joints of Two Base Metal Ceramic Alloys: Supercast and Minalux
Background: Different soldering techniques have a variety of applications in dentistry. One of the most important uses of soldering is to join multiple-unit fixed partial dentures together. In this Study, two base metal alloys (Supercast and Minalux) were soldered and their tensile, compressive and flexural strengths were measured and compared to each other. Materials and methods: In this ...
متن کاملIn vitro comparative evaluation of mechanical properties of temporary restorative materials used in fixed partial denture
INTRODUCTION Materials used to fabricate provisional restorations can be classified as acrylics or resin composites. Provisional crows can be either prefabricated or custom made. ACRYLICS These materials have been used to fabricate provisional restorations since the 1930s and usually available as powder and liquid. They are the most commonly used materials today for both single-unit and multi...
متن کاملThe effect of different fiber reinforcements on flexural strength of provisional restorative resins: an in-vitro study
PURPOSE The aim of this study was to compare the flexural strength of polymethyl methacrylate (PMMA) and bis-acryl composite resin reinforced with polyethylene and glass fibers. MATERIALS AND METHODS Three groups of rectangular test specimens (n = 15) of each of the two resin/fiber reinforcement were prepared for flexural strength test and unreinforced group served as the control. Specimens w...
متن کامل