Aim: The purpose of this in-vitro study was to evaluate the effect of repeated heat pressing of zirconia- reinforced -lithium disilicate on the marginal adaptation of occlusal veneers.
Materials and Methods: forty resin dies, duplicated from mandibular left first molar typodont tooth that was prepared to receive occlusal veneer, were equally divided into two groups (n=20) as follow; Group 1 (pressed specimens) included resin dies received occlusal veneers fabricated from freshly pressed Vita Ambria ingots, while Group 2 (re-pressed specimens) included resin dies received occlusal veneers fabricated from repressed buttons, which were remnants from the initial pressing. Cementation of the occlusal veneers was done using dual cure resin cement. Marginal fit was assessed using a stereomicroscope after thermocycling. Statistical analysis was done by using an independent sample T-test for comparing the two groups.
Results: The highest average values marginal gap were recorded in Group 2 while the lowest average values were observed in Group 1, however the difference between groups was statistically non-significant, as determined by the independent sample T-test (p > 0.05).
Conclusion: It was concluded that repeated pressing of leftover material has no statistically significant effect on the marginal adaptation of zirconia-reinforced lithium disilicate occlusal veneers.