Internal fit evaluation of all ceramic restoration fabricated by two CAD/CAM milling systems using cone beam CT (CBCT)

Abstract

Objective: to evaluate the internal fit of all ceramic restoration fabricated by two CAD/CAM milling systems using cone beam CT (CBCT). Materials and methods:A total number of 20 all ceramic restorations were manufactured in this study, and were equally divided into two main groups (n=10) according to the type of CAD/ CAM system used in the manufacturing process. Group I (Cerec in-lab system) and group II (Everest system) using the e.max CAD blocks specified for each milling system. specially designed stainless steel die was manufactured with specified dimensions. The die was scanned, the all ceramic restoration was designed and milled according to the different CAD/CAM milling systems used, and then crystallization procedure was carried. Duplication of the metal die into epoxy resin dies was performed and the final all ceramic restorations were the placed over the epoxy resin dies and examined for internal gap measurement using cone beam computed tomography (CBCT). Numerical data were explored for normality using Kolmogorov-Smirnov test of normality. Normally distributed (parametric data), were presented as mean, standard deviation and were compared between groups using independent t test. Non-parametric data were compared between groups using Mann Whiney U test. Gingival, axial and occlusal segments were compared using Friedman test and Wilcoxon signed rank test. The significance level was set at p < 0.05. Statistical analysis was performed with SPSS 18.0 for windows.Results: Comparison between groups using the mean of the 3 successive sections in buccolingual section revealed that a higher mean value was recorded in Cerec for each of the gingival, axial and occlusal segments, with no statistically significant difference between groups (p=0.138, p=0.06, p=0.276 respectively), while in mesio distal section a higher mean value was recorded in Cerec in the gingival and axial segments, with no significant difference between groups (p=0.296,

Marginal Accuracy of Monolithic Zirconia Crowns with Vertical and Horizontal Margin Configurations after Thermomechanical Fatigue

“…Twenty epoxy resin dies were fabricated by impression duplication of the 2 prepared molars. This technique was selected to achieve standardization and permit a reliable comparison between the two different groups (17) .…”

Internal fit evaluation of indirect restorations fabricated from CAD/CAM composite blocks versus ceramic blocks in badly broken teeth using cone beam CT (CBCT): double-blinded randomized clinical trial

“…The majority of authors approve that marginal discrepancies in the range of 100 μm appear to be clinically acceptable with regard to longevity of the restorations. Others claimed that marginal discrepancies exceeding 100 μm are clinically inadequate [ 23 , 24 , 25 , 26 , 27 , 28 , 35 , 36 ].…”

“…These 3D imaging techniques either using optical scanners such as triple-scan technique, or using x-rays, such as in case of micro-CT and cone beam computed tomography (CBCT). At the present, the cone beam computed tomography (CBCT), considered as an evolution of digital dentistry, is a non-invasive diagnostic system that permits quantitative analysis of the internal gap of all ceramic restorations [ 23 , 24 , 25 , 26 , 27 , 28 ]. As per available resources in the country, CBCT was the chosen method of measurement.…”

Two‑year clinical performance of indirect restorations fabricated from CAD/CAM nano hybrid composite versus lithium disilicate in mutilated vital teeth. A randomized controlled trial

“…Each prepared tooth was scanned using the Omnicam intraoral camera of the CEREC system software version 4.60 (Sirona Dental Systems GmbH, D- 64,625 Benshein, Germany) for taking the optical impression [ 23 ]. Using the CEREC software version 4.60, the margin was drawn, and the final design was obtained and checked.…”

“…After adjustments and cooling of the restorations, they were checked intraorally. The glazing cycle was done according to the preset glazing parameters instructed by the manufacturer [ 23 ]. Before cementation, the restoration fitting surface was treated with 4% hydrofluoric acid for 60 s and rinsed with water according to the manufacturer’s instructions.…”