Evaluation of Marginal and Internal Adaptation of CAD/CAM and Pressable Ceramic Veneers of Different Preparation Designs Using Silicone Replica Technique: (A Comparative in Vitro Study)

Background Accurate marginal and internal adaptation are a significant considerations for the clinical success of all ceramic restorations. The purpose of this study was to evaluate the marginal and internal adaptation of IPS e. max CAD and IPS e. max press ceramic veneers with two different preparation designs by using silicon replica technique. Materials and method A typodont maxillary central incisor was used for veneer preparation. Metal die was fabricated for each preparation deign, then each metal die was used to make twenty stone dies. The forty stone dies divided into four groups (n=10) according to the preparation design and the technique of veneer fabrication as follow Group I butt joint incisal reduction restored with IPS e. max CAD. Group II overlapped incisal reduction with palatal chamfer restored with IPS e. max CAD. Group III butt joint incisal reduction restored with IPS e. max press. Group IV overlapped incisal reduction with palatal chamfer restored with IPS e. max press. A silicone replica was obtained to measure marginal and internal adaptation of each ceramic veneer. A silicone replica was sectioned vertically and horizontally, Marginal and internal adaptations were evaluated by measuring the thickness of the light body silicone material at different points using digital microscope. Results Replica scores were analyzed with Two- way ANOVA and Independent sample t-test. The highest marginal gap was recorded for Group IV with highly significant differences when compared with other groups, followed by Group III, II, and I respectively. The fabrication technique and the preparation design showed significant effect on marginal gap values. There is no significant difference in internal gap between these four ceramic groups. Conclusion The pressable ceramic veneers with overlapped incisal reduction design produced higher marginal gap. There is no significant difference in internal gap between these four ceramic groups. only CAD/CAM Groups (Group I and II) showed a clinically acceptable total gap.