Aging of masticatory efficiency in healthy subjects: electromyographic analysis--Part 2.

The masticatory process identifies the level of the individual's masticatory ability and provides important information for an adequate diagnosis of the masticatory function. The purpose of this cross-sectional study was to evaluate the influence of age on habitual and non-habitual mastication by means of the values of the ensemble average of masticatory cycles. All volunteers were Brazilian, Caucasian, fully dentate (except for Group I--mixed dentition), aged 7-80 years and divided into five groups: I (7-12 years), II (13-20 years), III (21- 40 years), IV (41-60 years) and V (61-80 years). Except for Group V, which comprised nine women and eight men, all groups were equally divided with respect to gender (20 M/20 F). All subjects were nasal breathers, had normal occlusion and no parafunctional habits or symptoms of temporomandibular dysfunction (RDC/TMD). The masticatory process was analyzed during habitual mastication of peanuts and raisins, and non-habitual mastication of ParafilmM, for 10 seconds each. The resulting electromyographic data were evaluated using SPSS 19.0 software for Windows. ANOVA (analysis of variance) followed by the Duncan test were used to compare the efficiency of the masticatory cycle between age groups. Multivariate analysis (General Linear Models) was used to analyze the effect of age groups and gender on the efficiency of themasticatory cycle, to compare groups (p < 0.05). The results showed that age is directly associated with the changes in masticatory process in healthy subjects.