| Background:Masticatory function is an important criterion of evaluating prosthodontic treatments and orthodontic treatments. Masticatory efficiency tests known as the main means of evaluating masticatory performances, had attracted more and more attention. The methods of evaluating masticatory performances are divided into subjective and objective ways, and objective ways are widely used in the clinical application. Domestic masticatory efficiency tests mainly use screening method and absorbance method at present. These two kinds of evaluating system are mostly using natural food as their test food, of which physical and chemical property are not stable. The flushing process, the flowing rate and the standing time of the suspension have great impact on the results as will. These evaluating systems are limited in scope of application and difficult to develop a unified standard. The evaluating system of masticatory efficiency diversified in the last decades. Image analysis system, mixing ability test system and electromyography test system take part in evaluating the masticatory performance. The mixing ability test system usually have stable artificial test food, and convenient process. So it became one of the most valid and reliable test system of evaluating masticatory performances. The two-color chewing gum test and the two-color wax mixing ability test system have been established by external researchers, and their reliability and efficiency have been proved. However, artificial test food and highly sophisticated data analysis software of those test system are not easy to obtain in domestic situation. Research of the mixing ability test system of evaluating masticatory efficiency along with clinical use are rarely seen in our country.Objective:To assess feasibility of a newly developed artificial test food made by red wax and white chewing gum for evaluating masticatory function. And to develop an objective evaluation system for the masticatory performance.Methods:This study consists of two parts:Part 1. Each subject chewed the test food by one side. Mixtures were measured and the following five parameters were calculated:the ratio of colour mixed area(MIX). the ratio of area above 50?m in thickness to total area(TR), the ratio of maximum length to maximum width(LW). the shape factor showed how flat the sample was(FF) and the ratio of total area to the original size(TA'). Chewing tests were taken in three different times by 5 subjects. Calculated measurements were compared according time division. Chewing tests were taken by subjects with removable partial dentures. Tests were taken with and without removable partial dentures. Calculated measurements were compared according to these circumstances.Part 2. A total of 90 test foods were chewed by 35 subjects. Those samples were graded into three groups (good, medium and poor) by visual inspection. A discriminant analysis was performed using the five calculated measurements as predictors of the good group and poor group. IMA was calculated from the discriminant function.Result:Part 1. Chewing tests taken by same subjects, all these calculated parameters showed no significant difference between each group according time division (P>0.05). Wearing or not wearing removable partial dentures had statistically significance in MIX, LW, FF and TA'(P<0.05).Part 2. IMA was calculated from the discriminant function and using this index,96.5% of the samples were classified correctly. Chewing tests taken by same subjects, the IMA showed no significant difference between each group according time division (P>0.05). Wearing or not wearing removable partial dentures, the IMA showed significant difference according these circumstances (P<0.05).Conclusion:This newly developed artificial test food can be a possible choice for evaluating masticatory performance and this new system is easy to use. Therefore, it has high potentials for clinical use. |
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