A Comparative Study On Mandibular Movement For Digital Occlusal Adjustment

The purpose of this study was to evaluate the efficacy of different methods for digital occlusal adjustment, including mandibular movement trajectories, virtual articulators with individual movement parameters, and virtual articulators with default movement parameters. The occlusal adjustment of 20 single crowns and 20 three-unit splinted crowns was performed with 4 different strategies as following: static adjustment (STA), virtual articulator with default parameters (VAD), virtual articulator with individual parameters (VAI), and mandibular movement trajectories (MMT). The accuracy indicators, including mean deviation (MD), root mean square (RMS), and proportions of height variation with different ranges (PHVrange), were recorded to evaluate the accuracy of restorations. Analysis of variance (ANOVA) were used to analyze the difference (α=.05). The adjustment method significantly affected all accuracy indicators (P<.05). In all groups, MD values ranged from 0.18 ± 0.05 mm to 0.23 ± 0.02 mm, and RMS values ranged from 0.22 ± 0.02 mm to 0.25 ± 0.01 mm. The lowest MD values (0.19 ± 0.05 mm for SC, 0.18 ± 0.05 mm for TUC) and RMS values (0.23 ± 0.02 mm for SC, 0.22 ± 0.02 mm for TUC) were noted in the restoration adjusted with MMT, with the highest PHV-0.1∼0 mm and PHV0∼0.1 mm values. No significant differences were observed among groups of STA, VAD, and VAI. Dynamic occlusal adjustment using mandibular movement trajectories was more effective than adjustments made with a virtual articulator using individual or default movement parameters.