Analysis of the mechanical properties of food bolus masticated by denture wearers.

Masticatory performance of denture wearers was compared with that of the normal subjects by analyzing the behavior of the mechanical properties of the bolus. The index of the ability to comminute bolus was described as the total number of masticatory strokes until swallowing and therefore this was chosen as the first index. Principal Component Analysis (PCA) on the data of six parameters; 80% energy, elasticity, viscosity, hardness, adhesiveness, and cohesiveness, indicated that the cohesiveness was independent of the other parameters and should be evaluated as the second index of the ability to dilute bolus with saliva. Two factor scores of the other parameters were calculated using the standardized scoring coefficient obtained from PCA and factor analysis on the data of the normal subjects, which realized to compare two groups on the same plane of factor scores. The movement of factor scores on the factor plane would indicate the total behavior of mechanical properties of bolus and was chosen as the third index of the ability to knead bolus. Triangle Diagram (TD) was completed by using these three indices. On the TD, all the subjects were lower level at least in one index than the normal subjects in all the foods.