[Reproducibility of maximal bite force distribution over dentition]

We have reported that the analysis of the maximal bite force distribution over dentition was available for objective evaluation of prosthodontic treatment. The purpose of this study was to investigate the reproducibility of occlusal force distribution in maximal voluntary clenching. The maximal bite forces of 10 normal subjects with complete dentition were measured at close to intercuspation using Dental Prescale System. The measurements were performed two times with an interval of 3 years. The differences of the distributed occlusal force and the location of occlusal load center, i.e., the center of balance of distributed occlusal force, between 1st and 2nd measurement were evaluated by Mann-Whitney signed rank test (p < 0.01). The coefficient of variance was calculated from the results of two measurements in order to assess the measurement error. The statistical significant differences were not found in all measurement protocol and the coefficient of variance of the location of occlusal load center showed a remarkably small value (4.0%). The mean of absolute differences in the location of occlusal load center between two measurements were almost 4.0 mm anteroposteriorly and right-left. These results suggested that the maximal bite force measurement and the analysis of occlusal force distribution using Dental Prescale System were useful for the longitudinal evaluation of masticatory function and prosthodontic treatment. The analysis of occlusal load center was shown to be the most reliable method for evaluation. The reliable range for the reproducibility of occlusal load center was also shown.