Therefore, the intent of the present study was to evaluate the effect of cavity preparation depth and intraradicular extension on the marginal and internal fit and of resin-ceramic CAD/CAM endocrown restorations. 7 Presently, there are limited data available on the marginal internal adaptation 14 and no information about the effect of the intrapulpal extension on the fit of the endocrown restorations. 13 Intrapulpal extension of endocrowns may influence the retention and the adaptation of the restoration.
10, 12 A sufficient three-dimensional (3D) fit of the restoration has been considered mandatory to obtain maximum mechanical support of all-ceramic restorations from the tooth structure. 10, 11 Increased interfacial space and resin cement thickness may create increased polymerization shrinkage and interfacial stresses, resulting in decreased strength of the tooth-restoration interface.
Cerec optispray crack#
The cement interface has been described as a crack initiation area. 9 Internal fit is another key factor related to the long-term stability of esthetic indirect restorations. 8 Increased marginal discrepancies are related to increased exposure of the luting material to the oral environment, leading to chemo-mechanical degradation of the cement and the adhesive interface between the tooth structure, luting agent, and esthetic indirect restoration. Marginal and internal adaptation of indirect restorations are both very important parameters that may affect the periodontal status and longevity of the restorations. Increasing the intraradicular extension of endocrown restorations increased the marginal and internal gap of endocrown restorations. S/V calculations presented significant differences between H2 and the other two groups (H3 and H4) tested, with H2 again showing the lowest values. Significant differences were found in MG, MD, and internal gap width values between the groups, with H2 showing the lowest values from all groups. Marginal and internal discrepancy data (μm) were analyzed with nonparametric Kruskal-Wallis analysis of variance by ranks with Dunn's post hoc, whereas S/V data were analyzed by one-way analysis of variance and Bonferroni multiple comparisons (α=0.05). Marginal gap (MG), absolute marginal discrepancy (MD), and internal marginal gap were measured at various measuring locations and calculated in microscale (μm).
Cerec optispray software#
Horizontal and vertical tomographic sections were recorded and reconstructed by using the CTSkan software (TView v1.1, Skyscan).The surface/void volume (S/V) in the region of interest was calculated.
Specimens were evaluated by microtomography. Vita Enamic polymer-infiltrated ceramic-network material endocrowns were fabricated using the CEREC AC CAD/CAM system and were seated on the prepared teeth. Standardized preparations were made in resin endodontic tooth models (Nissin Dental), with an intracoronal preparation depth of 2 mm (group H2), with extra 1- (group H3) or 2-mm (group H4) intraradicular extensions in the root canals (n=12). The aim of the study was to evaluate the effect of preparation depth and intraradicular extension on the marginal and internal adaptation of computer-aided design/computer-assisted manufacture (CAD/CAM) endocrown restorations.