Margin Adaptation of Zirconia and Sintron Copings before and after Firing with Two Different Types of Porcelain

Introduction: Given the surge in the restoration of infrastructures with zirconia and sintron and the use of different porcelain on them and the lack studies on marginal adaptation in different situations, this study aimed to evaluate the marginal gap before and after porcelain firing. Materials & Methods: This cross sectional experimental laboratory research was performed in 2019 in the Transgenesis research center, Isfahan (Khorasgan) Branch, Islamic Azad University, where 40 abutments were divided into two groups of 20 with two types of substructures (zirconia and soft presintered chrome-cobalt alloy (Syntron) AmannGirrbach, Koblach, Austria)) then ,each group was subdivided into two porcelain subgroup of ten (noritake and creation).Marginal gap was evaluated by stereomicroscope before and after porcelain firing .Data was gathered and analyzed by means of one way and two-way ANOVA (α = 0.05). Results: The difference observed between marginal gap in studied groups was statistically significant (p value < 0.05). But marginal gap in respect to the type of porcelain did not show a significant difference between the groups (p value = 0.214). The lowest amount of change after firing with porcelain was related to the Syntron substructure group with Noritake porcelain, which was significantly different from the two zirconia frame groups (p value = 0.045), (p value = 0.006). Conclusion: In this research after porcelain firing, sintron showed better results compared to zirconia regardless of porcelain type.