Development and validation of a novel system that combines a new masticatory simulator and analysis method for...

During mastication, food undergoes state and texture changes influenced by various mechanical properties, including compression and fracturing of the molar teeth, mixing with saliva, and oral temperature. Prior studies have explored mastication simulators, however, no studies have assessed the forces and duration applied to the molars by the food during bolus formation. In this study, we developed a novel system that integrates a masticatory simulator and analysis method to evaluate mechanical properties. We developed ORAL-MAPS which is equipped with 6-axis force sensor, pneumatic pressure control mechanism, vertical movement, molar-like module, artificial saliva injection unit, and temperature control apparatus. A gap exists between the upper and lower unit at the closest point, allowing the sensor to measure vertical upward force and duration from food, while compressed air provides constant downward pressure. We hypothesized a correlation between the total integrated muscle activity ratio obtained from the human masseter muscle electromyography (iEMG). We compared the normalized impulse obtained from ORAL-MAPS with the normalized total iEMG obtained from human studies with four different types of gummy candies. As a result, the normalized total impulse of gummy candies A, B, C, and D were 1.00 ± 0.00, 1.29 ± 0.06, 0.95 ± 0.00, and 0.39 ± 0.0, respectively. The normalized total iEMG of the same gummy candies were 1.00 ± 0.00, 1.23 ± 0.15, 0.98 ± 0.09, and 0.45 ± 0.07, respectively. Thus, no significant difference was observed between the normalized total impulse obtained in vitro and the normalized total iEMG values for masticating the gummy candies B, C, and D (p > .05).