Measuring masticatory performance using a new device and β-carotene in test gummy jelly.

Objective methods for evaluating masticatory performance are invaluable for quantitative comparisons between various dental treatments as well as diagnosing masticatory disorder. The purpose of this study was to develop an accurate method for automatically measuring masticatory performance using a new measuring device consisting of light-emitting diodes and a photodiode and test gummy jelly. First, the relationship between six known β-carotene concentrations in aqueous solution and the voltage values exhibited on a photodiode was investigated. Mean voltage obtained by red light incident on the photodiode indicated a significantly high correlation (r=0·999 in a cubic function, P<0·01) with β-carotene concentration in the aqueous solution. Second, to establish the optimal measuring conditions for evaluating masticatory performance, factors influencing mean voltage were investigated, such as water temperature and times for rinsing the gummy jelly and dissolving β-carotene from the jelly. A stable mean voltage was obtained by measuring under the following conditions: rinsing water temperature, 35°C; rinsing time, 30s; water dissolving temperature, 35°C; dissolving time, 10s. Finally, the relationship between seven surface area values of divided gummy jelly and β-carotene concentrations dissolved from the divided jellies was investigated. The increase in surface area of divided test gummy jelly particles was accurately calculated (r=0·992, P<0·001) from mean voltage on the photodiode to change with β-carotene concentration dissolved from the jelly surface. This new method using test gummy jelly and an automatic measuring device appears useful for precisely evaluating masticatory performance.