Extraction orthodontias and masticatory muscle activity

ABSTRACT

To study the effect of extraction orthodontics on the occlusal force and muscle activity, right and left anterior temporalis and masseter muscles EMG were recorded in centric occlusion and during chewing of peanuts, before and two weeks after extraction of four first premolars. The studied sample was composed of 12 orthodontic patients, 6 males and 6 females of age range from 13.5 to 19 years. For each subject, treatment entailed the extraction of the four first premolars after thorough analysis. The data collected were statistically analysed and the following conclusions can be drawn. 1-A highly significant reduction [p < 0.01] of the activity of both muscles in the recorded two positions were reported after extraction. 2- Both sexes were affected undifferently. 3- The percentage change in the muscle activity during centric occlusion was higher than that occurring during chewing of hard food. 4-A precise analysis should be done if extraction is to be considered during orthodontic treatment to avoid impairment of the stomatognathic system