Effect of occlusal vertical dimension on swallowing patterns and perioral electromyographic activity

Abstract

Abnormal swallow patterns have been associated with specific dentofacial traits, such as an anterior open bite, but the cause-effect relationship between swallowing and malocclusion remains highly controversial. The aim of this research was to determine the effects of acute change in occlusal vertical dimension (OVD) on intraoral pressure swallow patterns and perioral electromyographic activity (EMG) during swallowing. Ten volunteers (five female, five male; 27-32 years) repeated standardised swallowing tasks as the OVD was progressively increased using mandibular trays of different heights. Standardised swallowing tasks were performed repetitively with each tray in place. Individual swallowing waveforms were quantitatively and qualitatively analysed. Peak pressure, swallow duration, time to peak pressure and lip EMG peak activity were assessed for each swallow. Data were analysed using mixed-model analysis. As OVD increased, lip peak pressure during swallowing increased almost threefold (+2·1 kPa; P ≤ 0·001), whereas swallow duration increased by 12·7 per cent (+160 ms; P = 0·01) at lip level and by 26·4 per cent (+270 ms; P < 0·001) at tongue level. Perioral muscle activity during swallows increased by 43·7 per cent (P ≤ 0·01) up to the OVD where resting lip seal was not attainable. Swallowing waveforms varied markedly between individuals, but interindividual waveforms were only minimally affected. The adaptive response and the waveform similarities associated with OVD variation supports the existence of a central control mechanism for swallowing, which may be modified by peripheral inputs.

Oral dysfunction as a cause of malocclusion

“…Atypical swallowing develops as a compensatory movement pattern when normal movement is inhibited in some way. A tongue thrust swallow involves excessive perioral effort and the tongue exerts forward and/or lateral pressure into the teeth, rather than vertical pressure into the hard palate with a front to back motion . Lingual‐palatal stabilization for the swallow is far weaker in children with PCB .…”

“…A tongue thrust swallow involves excessive perioral effort and the tongue exerts forward and/or lateral pressure into the teeth, rather than vertical pressure into the hard palate with a front to back motion. 39 Lingualpalatal stabilization for the swallow is far weaker in children with PCB. 40 This swallowing pattern reinforces a low resting posture, contributing to HNP, PCB and further malocclusion.…”

The effect of tongue thrusting on tongue pressure production during swallowing in adult anterior open bite cases

“…Various studies have reported on tongue dynamics during swallowing in patients with anterior open bite or in a state simulating anterior open bite on experimental occlusal elevation . Of these methods, electropalatography and measurement of tongue pressure have been widely used to evaluate tongue dynamics during swallowing, because tongue pressure has been identified as one cause of malocclusion .…”

“…Of these methods, electropalatography and measurement of tongue pressure have been widely used to evaluate tongue dynamics during swallowing, because tongue pressure has been identified as one cause of malocclusion . However, complex appliances need to be manufactured for each patient, and an acclimation period is required after fitting of the appliance, meaning that there has been no suitable method of easily obtaining a large volume of data in routine clinical practice thus far.…”

“…Various studies have reported on tongue dynamics during swallowing in patients with anterior open bite or in a state simulating anterior open bite on experimental occlusal elevation. 3,4,[8][9][10][11][12][13][14][15] Of these methods, electropalatography and measurement of tongue pressure have been widely used to evaluate tongue dynamics during swallowing, 4,12,13,15 because tongue pressure has been identified as one cause of malocclusion. 16 However, complex appliances need to be manufactured for each patient, 4,12,13,15 and an acclimation period is required after fitting of the appliance, 4 meaning that there has been no suitable method of easily obtaining a large volume of data in routine clinical practice thus far.…”