Effect of a dual-heating microwave sintering process on the fit of 3-unit full-contour zirconia bridges

Purpose: This study aimed to investigate the effects of microwave and conventional sinter- ing methods on the marginal and internal fit of 3-unit full-contour zirconia bridges. Methods:The zirconia specimens were designed as 3-unit full-contour bridges, and a total of 20 units were fabricated.Ten specimens of each commercial zirconia brand were divided into two subgroups (n=10) and sintered at a maximum temperature of 1,530C using two methods: conventional and microwave sintering.The marginal and internal fit of the preshaded zirconia prostheses was evaluated using the silicone replica technique, followed by the two-dimensional analysis.An independent sample t-test was then performed to compare and analyze the data between the two groups (=0.05). Results:The results showed no significant difference in the fit of zirconia bridges between the groups (p>0.05).All specimens remained within the clinically acceptable limit of 120 m, indicating that the microwave speed sintering protocol is suitable for clinical application. Conclusion:This study demonstrates the potential of the microwave sintering method as a viable alternative to conventional furnace sintering.It not only significantly reduces the processing time but also helps achieve a precise fit that ensures long-term clinical outcomes.