Lateral preference in mastication: an electromyographic study

To study concurrence of specific electromyographic chewing patterns and the side of mastication, twelve subjects chewed gum for 15, 20 and 25 s. Gum bolus placement on the right or left side of the dentition was estimated by three series of visual inspections. Contraction patterns of the chewing and non-chewing side masseter muscles were appraised by integrated and cumulative surface electromyography. Consistent and predominant gum bolus placement on the right side of the dentition could be predicted fairly reliably from comparative electromyographic observations. This was also the case in instances of consistent left-sided gum bolus placement, but not in predominant left-sided bolus placement. The latter phenomenon was explained by deviant observations made in two subjects only. Agreement between a presumed chewing side and a predictive contractility pattern was established in 78% of observations (P less than 0.001).