Hacettepe Dişhekimliği Fakültesi Derg.(. Clinical Dentistry and Research), vol.44, no.2, pp.57-66, 2020 (National Refreed University Journal)
Background and Aim: To evaluate the effect of anatomical and semi anatomical occlusal surface preparation designs on the marginal and internal adaptation and to compare the fracture strength of crowns fabricated from three different CAD/CAM blocks.
Material and Methods: Two maxillary right first molar were prepared on a typodont model (Standard Model ANA4; Frasaco) according to the two occlusal surface preparation design; anatomical (A) and semi-anatomical (SA). Sixteen crown restorations were processed each from 3 different CAD/CAM blocks; glass ceramic in a resin interpenetrating matrix crown (Vita Enamic) (Group EN), flexible nano-ceramic crown (GC Cerasmart) (Group CS) and fiber reinforced composite crown (Trinia) (Group FRC). The replica technique and a light microscope (×40) were used to measure the marginal and internal adaptation at 5 preselected locations. Crowns were loaded until fracture in a universal test machine. Data were analyzed by two-way ANOVA and Tukey HSD post-hoc test (p=.05).
Results: Type of restorative material had significant influence (P<.05), but occlusal surface preparation had no significant influence on marginal and internal adaptation (P>.05). Both the occlusal surface preparation and the type of material had significant influence on fracture strength (P<.05). The highest fracture strength values were obtained with FRC crowns and the lowest values were obtained with EN crowns in both preparation designs (P<.05).
Conclusion: The crown materials demonstrated clinically
acceptable marginal and internal adaptations. Type of occlusal
preparation design had no significant effect on marginal and
internal adaptations but had significant effect on fracture
resistance. Anatomic occlusal preparation resulted in higher