ABSTRACT
Examining the marginal fit of two occlusal veneer designs constructed of various ceramic materials, both before and after going through an aging process.
Material and methods
two groups (n = 10 each) were randomly assigned to the occlusal veneer material. First group received occlusal veneers named Celtra Duo composed of reinforced lithium silicate , while second group received Vita Enamic occlusal veneers made of hybrid ceramic infiltrated with polymers. Based upon the preparation design, each group was further subdivided into two subgroups (n = 5 each). Conventional occlusal reduction was used in the first grouping, and occlusal surface reduction + 1 mm of axial reduction with a rounded shoulder finish line was used in the second. the marginal gap was assessed .The marginal gap measurements statistically evaluated using independent t-tests and a three-way ANOVA. At p<0.05, the results were deemed significant.

Results
The results showed that the marginal gap between the two preparation designs of the two materials before aging did not differ statistically significantly (p<0.05). After aging, there was no significant difference between the two designs as the Celtra subgroups showed marginal gaps of 91±14 μm and 89±12 μm for the traditional and rounded shoulder designs, respectively. The marginal gap discrepancy was shown to be significantly influenced by the interaction between the materials, preparation designs, and aging techniques, as indicated by the results of the ANOVA test.

Conclusion
Celtra Duo demonstrated better marginal adaptability.