Evaluation of Marginal and Internal Fit of CAD/CAM Endocrowns with Different Cavity Tapers.

PURPOSE To evaluate the effect of cavity tapering on the marginal and internal adaptation of endocrowns fabricated from two different ceramic materials. MATERIALS AND METHODS Two mandibular molar model teeth were prepared with two different cavity tapers (5 and 10 degrees). Forty endocrowns in four groups (n = 10 each) were milled using lithium disilicate and zirconiareinforced lithium silicate ceramics for each cavity taper. The marginal and internal adaptation were measured with a stereomicroscope (×30) at 18 different points. The data were statistically analyzed using independent t test (P < .05). RESULTS A statistically significant difference was shown among the tested groups at 10 degrees of taper (P < .001). At 5 degrees of taper, the difference was insignificant. The greatest internal gap was observed on the pulpal floor in all tested groups. CONCLUSION All materials had clinically acceptable internal and marginal gaps; however, lithium disilicate ceramic had significantly better adaptation at 10 degrees of taper.