Analysis of Chewing Paths in Deciduous and Mixed Dentition

Abstract

     We investigated how human chewing path movements change from the deciduous through the mixed and into the permanent dentitions. We analyzed the changes from the deciduous dentition to the mixed dentition having four completely erupted permanent first molars. The chewing paths of children in the above two dentitions were then compared with those of adults.
     Ten children with normal deciduous dentition were tested. Six of them were later tested during the mixed dentition phase, and ten adults were used as controls. Japanese fish cake (“kamaboko”) was used as the test food and the chewing movements were recorded on a modified MKG-K6 system.
     The results were as follows:
1.  Between the deciduous and mixed dentitions, as the value of the opening time increased, the values of both the closing time and cycle time increased. Although the maximum opening displacement, maximum anteroposterior displacement, maximum opening velocity, and maximum closing velocity tended to increase slightly, the maximum lateral displacement decreased.
2.  Compared with that of normal adults, the chewing paths of children with both deciduous and mixed dentitions tended to have lower values for maximum opening displacement, maximum anteroposterior displacement, and maximum opening and closing velocities. However, the maximum lateral displacement in children with deciduous dentition was greater than that in adults, although these values were similar for children with mixed dentition and adults.
     These results indicate that the chewing path of children approaches that of adults as the children develop from deciduous to mixed dentition. In particular, the values for maximum lateral displacement were similar for adults and children in mixed dentition.