A preliminary study on the digital evaluation of absolute marginal discrepancy of fixed dental prostheses

Abstract

Background In clinical practice, the control of the marginal fit of fixed dental prostheses is hindered by the evaluation method, which needs to be further improved to increase its clinical applicability. We aimed to develop a fully digital method to quantitatively evaluate the absolute marginal discrepancy of fixed dental prostheses based on the digital impression technology and reverse engineering software. Methods A digital workflow and the conventional impression combined with the lost-wax heat-pressed technique were adopted to separately fabricate ten glass ceramic fixed dental prostheses. These twenty fixed dental prostheses were seated on the abutment, and the absolute marginal discrepancy was evaluated using the method developed in this study. One-way analysis of variance was used to statistically analyze the measurement results. Results Using the fully digital quantitative evaluation method, the mean value of absolute marginal discrepancy for fixed dental prostheses fabricated by the conventional method was 106.69 ± 6.46 μm, and that fabricated by the digital workflow was 102.55 ± 6.96 μm. The difference in the absolute marginal discrepancy of three-unit all-ceramic fixed dental prostheses fabricated using the two methods was not statistically significant (p > 0.05). Conclusions The digital quantitative evaluation method for absolute marginal discrepancy was preliminarily established and applied in three-unit ceramic fixed dental prostheses. This study provided a fully digital quantitative method for the absolute marginal discrepancy of three-unit fixed dental prostheses, which allows for improvements in measurement, thus facilitated quality control of the marginal fit of fixed dental prostheses. This lays the foundation for the development of an automated software platform for evaluating marginal fit of dental prostheses.