Effects of image and education on the precision of the measurement method for evaluating prosthesis misfit

Statement of problem: Various methods for measuring prosthesis misfit have been suggested. Although the cross-sectional images between the crown and abutment are used to evaluate the misfit, the effects of the image and the observer's knowledge on the precision of measurement are unknown. Purpose: The purpose of this in vitro study was to investigate the effects of the image and of education on the precision of prosthesis misfit measurement methods using inter- and intraobserver variability analyses. Material and methods: The cross-sectional images in the margin were obtained using the computer-aided replica technique (CART), silicone replica technique (RT), and sectioning technique (ST). Twenty-five observers measured the absolute marginal discrepancy values in the images obtained from each group 4 times at an interval of 2 weeks; the observers went through different education sessions regarding the selection of the measurement points. The precision of measurement was determined and compared using the likelihood-ratio test statistic (α=.05) and the intraclass correlation coefficient with the linear mixed-effects model. Results: The CART group exhibited the smallest deviations in the measurement variations, followed by the ST and RT groups (P<.001). Additional education on misfit measurements generally decreased the deviation values in all the groups, but without any significant differences. Conclusions: The cross-sectional image obtained from the measurement methods and education on the evaluation method affected the precision of the prosthesis misfit measurement. Digital methods might be a useful tool to significantly enhance the precision of the measurements.