Marginal and Internal Fit of All-ceramic Crowns Fabricated with Two Different CAD/CAM Systems

Abstract

This study evaluated the accuracy of marginal and internal fit between the all-ceramic crowns manufactured by a conventional double-layer computer-aided design/computer-aided manufacturing (CAD/CAM) system and a single-layer system. Ten standardized crowns were fabricated from each of these two systems: conventional double-layer CAD/CAM system (Procera) and a single-layer system (Cerec 3D). The copings and completed crowns were seated on the abutments by a special device that facilitated uniform loading, and the marginal discrepancies were measured. Internal gaps were also measured using a low-viscosity silicone material. Marginal discrepancies of Procera copings were significantly smaller than those of Procera crowns and Cerec 3D crowns (p<0.05), but Procera crowns and Cerec 3D crowns did not differ significantly from each other (p>0.05). On internal gaps, Cerec 3D crowns showed significantly larger internal gaps than Procera copings and crowns (p<0.05). Within the limitations of this study, the single-layer system demonstrated acceptable marginal and internal fit.

A 3-dimensional accuracy analysis of chairside CAD/CAM milling processes

“…[19][20][21][22][23] mm. 24 Relatively large internal gaps can result from the milling process, 25 but gaps of up to 150 mm are clinically tolerable. 26 The marginal gap differs among CAD/CAM systems, [27][28][29] but with the continual development of milling machines, marginal gaps are becoming progressively smaller.…”

“…Additionally, previous studies have evaluated fit with the elastomeric putty-wash technique, with low-viscosity silicone to duplicate the cement space and evaluate it photometrically or analyze it based on its density and weight. 24,25 Achieving clinically relevant results may require between 50 and 230 measuring points. 38 Modern computeraided techniques can better evaluate the fit of the restoration, because they yield much more extensive and informative data in 3 dimensions.…”

Evaluation of the adaptation of zirconia-based fixed partial dentures using micro-CT technology

“…Different techniques and tools are available to evaluate the restoration adaptation. [19][20][21][22] Recently, a methodology involving micro-computed tomography (micro-CT) was proposed as a reliable and non-destructive technique to evaluate the internal and marginal adaptation of dental restorations. However, there are only few studies that use this methodology for this purpose in the dental field.…”

SEM evaluation of the precision of fit of CAD/CAM zirconia and metal-ceramic posterior crowns

“…Most methods for evaluating the internal marginal fit, however, involve the use of an intermediate material to create a replica of the interface. One such material is fluid silicone 24,25,28,31) , which may be subsequently weighed to calculate the gap or whose thickness is measured, by cross-sectional measurements of the replica material, examined under microscope or photographed for analysis using image management software, to ascertain the space occupied by the cement 22,24,26,[32][33][34] . This type of evaluation has inherent errors, such as cut being oblique and resulting in the introduction of error into the measurement 34) .…”