Masticatory laterality – evaluation and influence of food texture

Abstract

The purpose of this study is the objective and quantitative evaluation of masticatory laterality and its daily variability. Various foods with different textures were used to investigate whether food texture influenced masticatory laterality. Ten healthy subjects and seven foods were used. Recordings of chewing movements were repeated three times at intervals of 1 week. Masticatory laterality was assessed with an Asymmetry Index [AI: (number of right side strokes - number of left side strokes)/number of total strokes]. Medians and ranges of the three recordings were calculated. The observed AI ranges in the three trials were limited with the exception of two subjects. Among the other subjects, averages of the absolute values of the medians were from 32.5 to 73.4%. Statistically significant differences between the hardest food and softer foods were observed in absolute value of AI medians. Masticatory laterality could be evaluated by an AI. Eight of 10 subjects showed limited ranges of AI in three recordings. It should be noted that a few people actually chew on either side but might chew on one side only on a particular day. Hard food evoked more masticatory laterality, and seemed more appropriate for laterality examinations.

Relationship between chewing side preference and handedness and lateral asymmetry of peripheral factors

“…3,5,26 In this study, most subjects preferred to chew on the right side, as was found by other authors. 10,11 Peripheral factors such as side differences in occlusal contact area and in bite force showed a positive and significant correlation with masticatory laterality.…”

“…Chewing gum was used in most studies, 2,4,7,9,10,13,14,25 although carrots, 3,16 almonds 18 and other foods have also been used. 11,26,27 It is known that the size, texture and hardness of the bolus affects muscle activity and the chewing cycle. 5,11,15,[26][27][28] Although most studies of masticatory performance use tablets of a silicone impression material, 29,30 no studies have assessed chewing side preference using this standardised test food.…”

“…3,[13][14][15][16][17][18][19][20][21][22] The discrepancies in the literature can be explained by differences in the study population, in the methods for determining the preferred chewing side and in the type of test food used. Most studies were performed with young adults with natural dentition, 2,9,11,26 others studies were carried out with children, 7 teenagers 21 or elderly people. 10 Since the notion of preferred side of mastication has no universal definition, 15 some methods determined which side the food was mostly chewed on, 2,4,7,10 others assessed the side the jaw moved to in the closing phase of mastication, 9,11,18,25,26 and a few studies used a questionnaire to assess the preferred chewing side by means of the subjects' perceptions.…”

Is the side with the best masticatory performance selected for chewing?

“…This threshold was selected in order to obtain three balanced groups and according to other studies. 16,17 Page 9 of 20 A c c e p t e d M a n u s c r i p t 9 Statistical analysis was performed using the spss software package (version 20.0; SPSS, Chicago, IL, USA) and P-values below 0.05 were considered significant.…”

“…The side of mandible lateralisation while closing was counted for each chewing cycle using a slow-speed playback mode to calculate masticatory laterality. The asymmetry index (AI) for each free-style mastication of bagged or unbagged silicon, was calculated according to Mizumori et al, 17 as…”