Mechanical Monitoring Devices For The First Bite And Preliminary Experimental Application

The first bite is an interaction of food and human incisors. The inherent mechanical properties and masticatory system have a joint effect on the performance of this process. The performance of bite force and incisor movements during the first bite can display the condition of masticatory system and the effect of inherent mechanics of the food, which makes the first bite research have a practical use for stomatology, prosthetic dentistry, biomechanics and food texture properties. Based on that, this research tries to make a device for monitoring the vertical bite force and horizontal bite force and a device to tracing the3D mandible movements during the first bite. With proper subjects, preliminary experiments have been done to monitor the first bite of biting samples with different size and mechanical properties.The mechanical devices in this research include bite force measurement device and a tracking device for mandibular movements. The bite force sensor is an elastic component with two strain gages on the upper surface and side surface to detect the special deformation. During the experiment, the sensor should be embedded into a complete denture, the vertical biting force and horizontal biting force around incisors would be measured. The mandible movements tracing facility is based on Hall Effect. Its design follows one of the oldest jaw movement devices called MKG (mandibular kinesiograph). A program is written in VB to process the Hall voltages to get the spatial values. With mapping software like MATLAB, the movement locus could be gotten. Before the preliminary application, the two tools have been tested to be stable and accurate enough in the lab to apply to experiments.Before the experiments, the experiment food will be determined and some mechanical properties will be measured by compression test, such as elasticity modulus and compression strength. During the experiments, the samples with different sizes and mechanical properties are bitten by the subject with his incisors only, the tools will monitor the whole process and a DV will record all the experiment process. With the information gotten, some fitting algorithms are used to analyze the correlation of samples’ properties and bite parameters. The results of experiments indicate that the lab-made devices can be used to monitor the2-D bite force and3-D mandibular movements; vertical biting force and horizontal biting force hit their peak value at the same time; the value of vertical biting force is affected by the sample’s size, elasticity modulus and compressive strength, but the influence model is not clear; the horizontal displacement is affected by the strain capacity of the food.