The influence of different CAD/CAM materials on the marginal fit of endocrown with different cavity depths (A comparative in-vitro study)

To evaluate and compare the influence of dissimilar CAD-CAM material on the marginal fitness of endocrown with different cavity depths. Freshly extracted human maxillary first premolar teeth (n = 40) were selected for this study. Teeth were decapitated 2 mm above the cement-enamel junction from proximal surface and endodontic treatment were performed for all teeth. Samples were allocated at two main groups (n = 20), according to cavity depth. Group A: 2 mm cavity depth; Group B: 4 mm cavity depth; and further subdivided into two sub-groups according to material used (n = 10): (A1 and B1) resinbased material; (A2 and B2) ceramic-based material. Teeth were prepared with butt joint margin and 10 degrees internal axial wall divergence. Afterwards, samples scanning was performed using InLab digital scanner. Endocrown restoration fabricated by Sirona Cerec InLab MCXL milling device and adhesively luted with a resin cement (RelyXTM Ultimate ClickerTM, 3 M ESPE). All samples were subjected to thermocycling. After thermocycling, marginal gaps were measured using stereomicroscope at a magnification of 45X. The recorded measurements were collected, scaled and statistically analyzed. A resin-based endocrown showed significantly a smaller vertical marginal gap than ceramic-based, an endocrown with 2-mm cavity depth showed significantly lower marginal gap than one with 4-mm cavity depth. Increasing the cavity depth of endocrown preparation negatively affect the marginal fit. Resin-nanoceramic endocrown showed better marginal fit than glass ceramic endocrown. Both tested CAD/CAM materials showed clinically acceptable vertical marginal gap. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Advances in Mechanical Engineering and Nanomaterials