Nishi, Shamima Easmin
(2020)
Prospective evaluation of facial and masticatory muscles activity in different malocclusion patients : an electromyography study.
PhD thesis, Universiti Sains Malaysia.
Abstract
Mastication procedure involves muscular activity by chewing, swallowing and
digestion of food where the occlusal surfaces of the teeth are involved for crushing and
grinding of solid foods. It is well established that malocclusion patient exhibits a
decrease in masticatory performance when compared with normal occlusion. This
study aimed to investigate and compare the effect of the facial (buccinator and
orbicularis oris) and masticatory (masseter and temporalis) muscle activity via surface
electromyography (sEMG) in orthodontic patients pre and at 6 months of the
orthodontic treatment. Malay patients with different types of malocclusion (Class I, II
div 1, II div 2 and III) were selected through screening from the Specialist Orthodontic
Clinic, Hospital Universiti Sains Malaysia. After taking the informed consent, patients
were randomized, and the treatment plan was done with the final diagnosis. According
to the objectives and sample size, patients were subdivided into different groups such
as laser and non-laser groups; extraction and non-extraction groups and three different
brackets groups (conventional, self-ligating and ceramic brackets). sEMG of muscles
were done by using a two-channel electromyography device, where pre-gelled and
self-adhesive electrodes (bilateral) were used. sEMG activity of masseter, temporalis,
buccinator and orbicularis oris muscle were recorded during different action (chewing,
clenching, blowing and smiling) before and at six months of fixed orthodontic
treatment. In the statistical analysis, Class II div 1 malocclusion presented with higher
muscle activity in comparison to Class I, Class II div 2 and Class III malocclusion.
There was a significant difference found in the chewing activity of the right masseter
muscle (P= 0.025) with different overjet. Furthermore, malocclusion patients with
different overbite showed a significant difference in blowing activity of lower
orbicularis oris during 1st blow (P=0.007), 2nd blow (P=0.005), the high peak of 1st
blow (P=0.014) and the high peak of 2nd blow (P=0.011). The present study showed a
significant difference in right buccinator muscle activity during 1st smile (P= 0.040)
with different face profile. However, the smiling activity of upper orbicularis oris
showed significant differences during rest (P= 0.048), 2nd smile (P= 0.038), the high
peak of 1st smile (P= 0.041) and the high peak of 2nd smile (P= 0.032) with different
lip competency. Analysis of repeated measured ANOVA showed a significant
difference in muscle activity between extraction and non-extraction treatment
procedure. The patient who received conventional bracket for orthodontic treatment
showed higher EMG activity in compare with self-ligating and ceramic bracket groups.
Class II div 1 malocclusion patients who were treated with conventional bracket
system and received LLLT (low level laser therapy), presented higher muscle activity
in comparison with the self-ligating bracket system.
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