Objective: To evaluate the effects of age and dental status on chewing performance in humans.
Design: Electromyography recordings (EMG) were made during chewing of six foods (rice, beef, cheese, crispy bread, apple, and peanuts) to compare the masticatory patterns of four subject groups with different ages and dental status.
Subjects: Nineteen elders (mean age 67.2 years) classified into three categories according to their number of opposing post-canine teeth pairs (i.e. functional units) and a control group of 10 young adults (mean age 26.5 years) with a high number of functional units.
Main outcome measures: Number of chewing cycles, chewing time, total muscle activity and muscle activity per chew, burst and inter-burst durations, maximum and mean voltages from EMG recordings.
Results: Time-related EMG parameters increased from young subjects to elderly subjects with high, middle and low dental status. Parameters related to EMG voltages per chew decreased in the same order among the different groups of subjects. These tendencies were observed for all the studied products. Subjects with weak muscle contraction may compensate for their poor chewing performance by lengthening both chewing cycle and sequence duration. Additional alterations in the chewing patterns were observed when age effect was associated with a dental status degradation in terms of number of functional units.
Conclusion: Impairment in mastication for the elderly is due to both ageing and decreasing number of functional pairs of post-canine teeth.