Do diff Do different Cavity Pr vity Preparation Designs Influence F ation Designs Influence Fracture Resistance of CAD/CAM Fabricated Ceramic Inlay and Onlay?

Abstract

Objectives: This study evaluated the impact of various cavity preparation designs on fracture resistance of computeraided design/computer-aided manufacturing ceramic inlays and onlays.

Patients and methods: A total of 48 teeth were randomly assigned to six groups (n ¼ 8) (group A) inlays with 75 % width of the inter- cuspal distance (ICD, buccal cusp tip-to-palatal cusp tip), (group B) inlays with 100 % width of the ICD, (group C) onlays that had a palatal  cusp reduction of 2.0 mm (functional cusp) and 75 % width of ICD, (group D) had a palatal cusp reduction of 2.0 mm (functional cusp)  with 100 % width of ICD, (group E) had a palatal cusp reduction of 2.0 mm (functional cusp) and a buccal cusp reduction of 1.5 mm  (nonfunctional cusp) and 75 % width of ICD, and (group F) had palatal cusp reduction of 2.0 mm (functional cusp) and had buccal cusp  reduction of 1.5 mm (nonfunctional cusp) and 100 % width of ICD. The fracture resistance of each group was measured using a universal  testing machine. Data were statistically analyzed using the ShapiroeWilk, one-way analysis of variance, and post-hoc Tukey tests.

Results:  One-way analysis of variance revealed statistically non-significant differences among the tested groups at (P < 0.05), however  significant difference was detected between group A (1857 ± 511) and F (3070 ± 804) (P ¼ 0.01).

Conclusions: The various types of  preparation designs had no significant difference in fracture resistance except for inlays with 75 % width of ICD.