Evaluation of the marginal fit of CAD-CAM zirconia copings: Comparison of 2D and 3D measurement methods

Abstract

Purpose: The purpose of this in vitro study was to compare the marginal fit of zirconia copings by using 2 different measurement methods: a triple optical scan method and a silicone replica method.

Material and methods: Sixty zirconia copings fabricated by computer-aided design and computer-aided manufacture (CAD-CAM) systems were studied for the marginal fit. For the replica method, the thickness of the light-body silicone layer of the discrepancy was assessed using light microscopy and image analysis software. The triple-scan optical method was performed to obtain a digital three-dimensional map of the marginal fit and analyzed marginal fit measurement values. For each method, the reliability of the measurement was tested, and a nonparametric analysis was then performed to compare the marginal fit values as measured by the 2 evaluation methods (α=.05).

Results: Intraclass correlation coefficients and repeatability coefficients revealed good repeatability for both of the evaluation methods. However, the triple-scan method produced a smaller marginal fit than the replica method (P<.001) for the entire group studied.

Conclusions: Although both methods showed good repeatability, the triple-scan method was more reliable.