Most Functional Pattern when Chewing Gummy-jelly

Objectives: In order to clarify the most functional pattern the stability of masticatory movements in healthy subjects was investigated. Methods: Fifty healthy subjects in their twenties (28 males and 22 females) were asked to chew gummy-jelly on the unilateral side for 20 seconds. The mandibular movement was recorded using MKG-K6I and the masticatory path was classified into seven patterns (I: smooth opening toward working side and convex closing, II: similar to I but concave closing, III: opening toward working side after initially toward non-working side, and convex closing, IV: similar to III but concave closing, V: convex opening and closing, VI: reverse pattern, VII: opening and closing crossing each other). The CVs (coefficient of variation) of the opening, closing, occluding, and cycle time were obtained as indicators for the stability of rhythm and the SD/ODs (standard deviation/opening distance) of the lateral opening and closing components, and vertical component were obtained as indicators for the stability of path. After principal components analysis, the comprehensive indicators for the stability of rhythm and path were established. Then the values of the comprehensive indicators of each pattern were compared among the chewing patterns. Results: The value of the comprehensive indicator was the smallest for pattern I (36.5±4.4), followed by that for pattern III (45.9±9.1), II (48.4±7.4), IV (50.7±11.5), V (51.1±11.6), VII (55.4±12.9), VI (66.2±11.6). There were statistically significant differences between pattern I and the others (p<0.01, s.), between pattern VI and patterns II, III, IV. Conclusions: From these results it was suggested that masticatory path pattern has a close relation with the stability of masticatory movements, and that the subjects with pattern I had a better masticatory function than the subject with the other patterns.