Effect of water temperature and duration of immersion on the marginal accuracy of provisional crowns

ABSTRACTBACKGROUNDFabrication of fixed restorations is time consuming. It is vital that the prepared teeth be protected by means of an interim restoration till the time definitive prostheses can be delivered. Marginal adaptation is one of the most important requirements for an interim restoration.METHODThis study was done to investigate the effect of water temperature and duration of immersion on the marginal accuracy of provisional restoration fabricated in autopolymerizing resin. The experimental model simulating a clinical situation was made. The test material was autopolymerizing methyl methacrylate.Specimens were subjected to different water temperatures for 5 and 10 minutes’, duration for continuing the polymerization. Marginal accuracy was determined by a travelling microscope under 100 × magnification.RESULTSThe measurements were tabulated and statistically analyzed using two way ANOVA technique. Results showed significant difference at all water temperatures. Marginal gaps were least when crowns were polymerized at 20°C for 5 minutes.CONCLUSIONStudy concluded that polymerizing the polymethyl methacrylate resin provisional crowns by direct technique in the water maintained at 20–30°C temperature for 10 minutes resulted in better marginal fit and this method can be utilized in clinical conditions for better results.