|Year : 2018 | Volume
| Issue : 3 | Page : 210-215
An electromyographic evaluation of orbicularis oris and masseter muscle in pretreatment and posttreatment patients of oral submucous fibrosis: A prospective study
Gunjan Sinha1, Manisha Lakhanpal Sharma2, CS Ram3
1 Department of Oral Medicine and Radiology, Hazaribag College of Dental Sciences and Hospital, Hazaribag, Jharkhand, India
2 Department of Oral Medicine and Radiology, ITS Dental College, Greater Noida, Uttar Pradesh, India
3 Department of Physiotherapy, ITS Physiotherapy and Biotechnology College, Ghaziabad, Uttar Pradesh, India
|Date of Submission||27-Jun-2018|
|Date of Acceptance||22-Jul-2018|
|Date of Web Publication||18-Oct-2018|
Dr. Gunjan Sinha
C/o A Srivastava, Indrapuri Road No. 4, Ratu Road, PO Hehal, Ranchi - 834 005, Jharkhand
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Oral submucous fibrosis (OSMF) is a chronic disease of insidious onset featuring the deposition of fibrous tissue in the submucous layer of the palate, fauces, cheek, lips, pharynx, and esophagus. The underlying muscles of mastication may be affected resulting in trismus and disability due to muscle hypertrophy. Aims and Objectives: To evaluate the electromyographic activity of masseter and orbicularis oris muscles in patients with OSMF and to compare pretreatment and posttreatment activity of masseter and orbicularis muscles in patients with OSMF and with healthy control. Materials and Method: The study comprised 60 individuals. They were divided into two groups. One group was experimental/study group comprising 30 clinically and histopathologically diagnosed patients with OSMF and control group included another 30 healthy age- and sex-matched individuals. The electromyographic activity was evaluated among study group and control group, pre- and posttreatment patients with OSMF. The results were statistically evaluated using Student's t-test, paired t-test, analysis of variance test, and Bonferroni test. Results: The results showed that electromyographic activity of both the muscles in control group showed statistically significant decreased activity when compared with patients with OSMF. Patients with OSMF posttreatment showed statistically significant decreased activity when compared with pretreatment patients. Conclusion: Electromyography can serve as a useful aid in detecting the involvement of the muscles of mastication and muscle of facial expression in patients with OSMF and effect of the treatment on the muscular activity in patients with OSMF.
Keywords: Electromyography, masseter muscle, muscle hypertrophy, oral submucous fibrosis, orbicularis oris muscle
|How to cite this article:|
Sinha G, Sharma ML, Ram C S. An electromyographic evaluation of orbicularis oris and masseter muscle in pretreatment and posttreatment patients of oral submucous fibrosis: A prospective study. J Indian Acad Oral Med Radiol 2018;30:210-5
|How to cite this URL:|
Sinha G, Sharma ML, Ram C S. An electromyographic evaluation of orbicularis oris and masseter muscle in pretreatment and posttreatment patients of oral submucous fibrosis: A prospective study. J Indian Acad Oral Med Radiol [serial online] 2018 [cited 2019 Mar 24];30:210-5. Available from: http://www.jiaomr.in/text.asp?2018/30/3/210/243646
| Introduction|| |
Oral submucous fibrosis (OSMF) is an insidious, chronic disease affecting any part of the oral cavity and sometimes the pharynx. Muscle dystrophy is seen in most of the cases of OSMF.
Overactivity during chewing areca nut causes ischemic changes, subsequent fibrosis, and scarring in the masticatory muscles. This contributes to fibrotic band formation and trismus.
Rajendran et al. 1994) suggested that restricted mouth opening in OSMF might depend on subepithilial fibrous bands and the extent of muscle degeneration. Vladimir Medved (2004) stated that electromyography (EMG) is an electro-diagnostic technique for evaluating and recording the electrical activity produced by skeletal muscles.
Therefore, a novel study using EMG as an adjuvant investigatory modality to evaluate the electromyographic activity of masseter and orbicularis oris muscles in patients with OSMF and to compare pre- and posttreatment activities of masseter and orbicularis muscles in patients with OSMF and with healthy control was done.
| Materials and Method|| |
It was a prospective study carried out for a duration of 3 months. Ethical clearance for the study was obtained from ethical committee of ITS Centre for Dental Studies and Research (registration no. RCR/697/Inst/UP/2014), Muradnagar, Ghaziabad, Uttar Pradesh, India. The study comprised 60 individuals between 20 and 50 years of age. They were divided into two groups. One group was experimental/study group comprising 30 clinically and histopathologically diagnosed patients with OSMF and control group included another 30 healthy age- and sex-matched individuals.
Detailed case history including personal history and a through clinical examination was carried out for all the patients and recorded in a customized case history porforma. The demographic data along with the habit index were recorded before clinical examination. The patients were divided into different clinical grades of OSMF, according to Khanna et al. classification, 1995. Healthy controls and patients with OSMF (both pretreatment and posttreatment) were subjected to both pretreatment and posttreatment electromyograpic assessment of masseter and orbicularis oris muscles bilaterally using surface electrodes. Muscular activity was recorded at maximum contraction state in microvolts. Patients with OSMF were given intralesional injection of triamcinolone acetonide 10 mg/mL, depositing approx 0.2 mL per site in buccal mucosa, and hyaluronidase 1500 IU biweekly for a duration of 3 months.
The principal of EMG is based on the mechanical function of a muscle that reflects the electrical events of a contraction. These include the time course of release of calcium from the sarcoplasmic reticulum, its binding to troponin, and the rates of cross-bridge formation during activation. The amplitude of EMG signal has the potential to provide a measure of the magnitude of muscle force. The signal measured at an EMG electrode is a voltage differential set up by the summed effect of multiple motor units depolarizing at varying distances from the electrode.
Electromyographic assessment of masseter and orbicularis oris was done after treatment and after a duration of 3 months, at the completion of the treatment for OSMF. Patients with a positive history of chewing areca nut or one of its commercial preparations and with clinically diagnosed cases due to gutka chewing were included in the study. Presence of any other disease that mimics OSMF such as systemic sclerosis, tetany, third molar impaction, a history of radiotherapy or chemotherapy, presence of any deleterious habit (e.g., bruxism), presence of other mucosal disease (oral cancer, lichen planus, and leukoplakia), all OSMF cases due to reason other than gutka, history of temporomandibular joint disorder or masticatory apparatus dysfunction, and congenital masseteric hypertrophy/atrophy were excluded from the study.
Grouping of OSMF disease was done according to Khanna et al. (1995). Patients of the study group were treated with intralesional injections for a period of 12 weeks. Patients were treated by a combination of triamcinolone acetonide, 10 mg/mL, and hyaluronidase (1500 IU) alternatively, biweekly, for 12 weeks. Fibrous bands were palpated and 26-gauge needle was used to inject the drug at multiple sites. Response to the treatment was evaluated every week. Improvement of burning sensation, tongue protrusion, mouth opening, and cheek flexibility were recorded at every visit for 12 weeks.
The patient was instructed not to chew anything in any form for a period of 2 h before EMG. The subject was asked to sit upright with their head in the natural position. The skin was cleaned with cotton swab soaked in 70% alcohol to reduce impedance. Electrodes were placed by applying a small amount of electromyographic gel on the recording site. A set of two silver–silver chloride surface electrode pairs of 10 mm diameter were placed at 3–4 mm in interelectrode distance. The paired electrodes acted as exploring electrodes for electromyographic recording to assess the pretreatment and posttreatment EMG activity of orbicularis oris and masseter muscles (amplitude). The measurement of masseter muscle was done in the thickest part of the muscle, close to the level of occlusal plane, approximately in the middle of the mediolateral distance of the ramus, determined by palpation while the subjects clenched [Figure 1]. The electrodes were placed near the angle of the mouth and the patient was asked to blow air forcefully for assessment of orbicularis oris muscle [Figure 2]. Muscle activity was recorded in the maximum voluntary contracted state. Peak-to-peak amplitudes were recorded in microvolts (μv) [Figure 3], [Figure 4], [Figure 5].
|Figure 4: Pretreatment electromyography reading of a patient with oral submucous fibrosis|
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|Figure 5: Posttreatment electromyography reading of a patient with oral submucous fibrosis|
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Statistical analysis was done using SPSS (Statistical Package for Social Sciences, IBM Statistics) Version 20.0 statistical analysis software. The values were represented in number and mean ± standard deviation. Significance is assessed at 5% level of significance. Various statistical tests such as Student's t-test, paired t-test, one-way analysis of variance (ANOVA), and Bonferroni test were performed to find out various results based on the aim and objectives of the study.
Student's t-test was applied to compare between case and control. Paired t-test was applied to compare between pretreatment and posttreatment cases. The comparison between different pretreatment groups was done using one-way ANOVA. ANOVA followed by Bonferroni was applied to compare between different posttreatment groups. Besides this, chi-square test was also applied in case sex compared in groups. P-value less than 0.05 was considered as significant.
| Results and Observations|| |
A total of 30 patients, diagnosed clinically and histopathologically with OSMF, were included in the study group, and the control group included 30 sex- and age-matched healthy individuals. In our study, male-to-female ratio was 28:2. The mean age was 31.23 ± 8.88 and 30.50 ± 8.32 years among case and control, respectively.
The pretreatment mean activity of right masseter, left masseter, right orbicularis, and left orbicularis oris muscles was found to be 696.57 ± 152.06, 703.97 ± 184.10, 230.10 ± 67.10, and 231.53 ± 73.09, respectively. The pretreatment mean activity of right masseter, left masseter, right orbicularis, and left orbicularis oris muscles was found to be 150.23 ± 15.64, 149.10 ± 13.99, 75.27 ± 8.92, and 75.10 ± 8.66, respectively, among healthy controls. Student's t-test was performed for comparison and the results were found to be significant [Table 1] and [Graph 1].
|Table 1: Comparision of Mean±SD of EMG activity of pre masseter and pre orbicularis among case and control|
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Electromyographic activity of muscles
The mean of right masseter, left masseter, right orbicularis, and left orbicularis at baseline was 696.56 ± 152.06, 703.97 ± 184.10, 230.10 ± 67.10, and 231.53 ± 73.09, respectively, among pretreatment, whereas it was 500.73 ± 171.81, 473.87 ± 201.99, 174.10 ± 56.27, and 179.07 ± 70.63, respectively, among posttreatment cases. Paired t-test was performed for comparison among pretreatment and posttreatment cases. The results were found to be significant [Table 2] and [Graph 2].
|Table 2: Change in electromyographic activity of muscles among pretreatment and post treatment cases|
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| Discussion|| |
The World Health Organization, in 1978, defined OSMF as a slowly progressive chronic insidious disease in which fibrous bands form in the oral mucosa, ultimately leading to severe restriction of movement of the mouth including the tongue. Rajendran et al., in 2003, reported that the disease is commonly seen in South East Asia but cases have also been reported worldwide like in Kenya, China, the United Kingdom, Saudi Arabia, and other parts of the world. Raina et al., 2005, reported that overall prevalence of OSMF in India is about 0.5% with a range of 0.2%–1.2% in different regions of the country. Vanaja Reddy et al., 2010, reported that the condition has its malignant potential rate of 7.6% and is particularly associated with use of areca nut in various forms with significant duration and frequency of chewing habits.
This study was conducted over a period of 2 years, with a study population including a total of 60 individuals, out of which 30 were patients with OSMF and 30 were healthy controls. There were 93.3% (56) males and 6.6% (4) females in the total study population. They were divided into two groups. One group was experimental/study group comprising 30 clinically and histopathologically diagnosed patients with OSMF and the other group was the control group, including 30 healthy, age- and sex-matched individuals. The study was designed to assess and compare the electromyographic activity of masseter and orbicularis oris muscles in healthy controls and patients with OSMF and change in pretreatment and posttreatment activities of muscle in patients with OSMF and intergroup comparison among patients with OSMF.
In our study, the majority of the patients were males, which can be attributed to male predilection as reported by Lia et al., 1995, Merchant et al., 1997, and Kumar et al., 2006. Merchant et al., 1997, stated the following three reasons for greater male prevalence. First, it could be that the severity is related to higher frequency and quantity of chewing areca nut among men than women due to occupational stress. Second, due to its stimulant or euphoric action, property of saliva stimulation, psychotropic effect, parasympathetic action, its role in digestion, hunger satisfaction, and its effect as a breath sweetener that results in more severe disease in younger cohorts of men when compared with older group and women.
The study group comprised male and female 20–50 years of age and the mean age was 31.23 ± 8.88 years. This age distribution is in congruence with study done by Shah et al, 1998.
Age criteria in this study was kept as 20–50 years to eliminate age-related declines in strength and activity attributed to decreased maximal voluntary activation of agonist muscle and/or changes in antagonist co-activation, as reported by Häkkinen et al., 2001. Age-related decrease in muscle mass and strength is often associated with decline in physical activity. Blood concentration of circulating anabolic hormones and growth factor, for example, testosterone, growth hormone, and insulin like growth factor I, also diminishes with age, thereby affecting the muscular activity.
Pullman et al., 2000, examined more than 2500 original articles, reviews, AND books to determine the scope of EMG utility, its benefits, and risks. They also assessed EMG's strengths and weakness for specific clinical applications and inferred that EMG is the only reliable method available for objective recording of a patient's muscular function.
The contracted state of the muscle was studied, because in this state more motor units are recruited which depend strongly on the muscle force output such as fiber length and velocity. At maximal voluntary contraction, a full recruitment pattern is produced which is referred as interference pattern of EMG amplitude as documented in a literature by Mills 2005.
The mean muscle activity of right masseter (150.23 ± 15.64), left masseter (149.10 ± 13.99), right orbicularis (75.27 ± 8.92), and left orbicularis (75.10 ± 8.66) of healthy control was found to be as stated, whereas the pretreatment activity of right masseter, left masseter, right orbicularis, and left orbicularis oris was 696.57 ± 152.06, 703.97 ± 184.10, 230.10 ± 67.10, and 231.53 ± 73.09, respectively. Thus, Student's t-test was performed and a significant difference, that is, P-value <0.05, was observed in the amplitude of the muscles among both the groups.
Chakarvorty et al., 2016, reported that masseter muscle is the bulkiest and strongest muscle of the face and maximum force is applied to it during mastication. Intensive use of any skeletal muscle may cause changes in muscle fiber size and composition, which in turn increases the strength of the muscle and resistance to fatigue. This is also true for masticatory muscles. Prolonged high activity of these muscles resulted in increased ultrasonographic thickness of the masseter muscle and increased maximal bite force values.
Corti et al., 2012, did a study to assess the electromyographic pattern of orbicularis oris during swallowing of different consistencies of food. They documented that amplitude of EMG activity of orbicularis oris changed during swelling as the consistency changes from water to solid food. Thereby, the authors concluded that masticatory stresses influence the increase in electromyographic activity of the muscle. It has been documented in the literature by Hakkinen et al, 1998, and Amorin et al., 2012, that hypertrophy of muscle could lead to increased activity of muscle. The authors inferred that muscle hypertrophy due to stress factor could influence the increase in electric activity of masticatory muscle. Our results have shown an increase in electromyographic activity of masseter and orbicularis muscles in OSMF group when compared with healthy controls due to the increase in masticatory stresses.
On comparison of pretreatment and posttreatment electromyographic activity of muscle there was change in the mean of all the muscles. The pretreatment electromyograpic activity recorded was 696.57 ± 152.06, 703.97 ± 184.10, 230.10 ± 67.10, and 231.53 ± 73.09 for right masseter, left masseter, right orbicularis, and left orbicularis, respectively. The posttreatment electromyographic activity recorded was 500.73 ± 171.81, 473.87 ± 201.99, 174.10 ± 56.27, and 179.07 ± 70.63 for right masseter, left masseter, right orbicularis, and left orbicularis. Paired t-test was performed and a significant difference with P- value <0.005 was observed between the amplitude of masseter and orbicularis muscles among pretreatment and posttreatment cases. This could be attributed to the treatment regime followed by the patients such as patients were advised to cessate their habit, administration of intralesional injection of triamcinilone acetonide, hyaluronidase, and mouth opening exercise.
Kamala et al., in 2010, documented that cessation of habits leads to decrease in masticatory stresses which in turn decrease the strength of the muscles and its resistance to fatigue, ultimately contributing to decrease in muscle thickness. Another study was done by Cesar FA, in 2011, on electromyographic analysis of masseter and anterior temporalis muscles in bruxers, before and after use of occlusal splint. He concluded that significant reduction in EMG activity was observed immediately after the insertion of occlusal splint. Thus, he concluded that EMG activity decreased on removal of masticatory stresses. Therefore, our study showed results in congruence with the already documented literature.
Saurabh Samdariya et al., 2014, reported that triamcinolone acetonide suppresses inflammatory reactions, thereby preventing fibrosis by decreasing fibroblastic proliferation and subregulating collagen synthesis and down-regulation of collagenase production. Hyaluronidase commonly acts by breaking down hyaluronic acid which leads to inhibiting action of sensitized lymphocytes following activation by specific antigens and by preventing or suppressing inflammatory reactions. The effects of triamcinolone and hyaluronidase are thought to be responsible for preventing trismus and fibrous band formation. Thereby, it helps reduce masticatory stress and resistance against functions.
Another reason is attributed to physiotherapeutic muscle stretching exercises for the mouth that were advised to the patient. This aids in preventing limitation of mouth movements as stated by Tai et al., 2001. The forceful mouth opening with the help of ballooning of mouth is thought to put pressure on the fibrous band.
Thus, it was observed that posttreatment electromyographic activity was reduced when compared with pretreatment electromyographic activity. Furthermore, intergroup comparison of muscle activity was done during pretreatment and posttreatment among different groups. One-way ANOVA test was performed for pretreatment cases and one-way ANOVA followed by Bonferroni test was done for posttreatment cases. Statistically, significant results were observed on comparison of group I with group II. In addition, differences were statically significant when group II/group III was compared with group IV. Whereas statistically, no significant difference was observed between group II and group III. This could be attributed to submucosal thickness and masseter hypertrophy that increases with advancing stage of OSMF.
| Conclusion|| |
The present prospective study of electromyographic activity for masseter and orbicularis oris muscles was carried out in patients with OSMF and in healthy control.
The following conclusion could be drawn from the observation of the study:
- There is an increased electromyographic activity of masseter and orbicularis oris muscles in patients with OSMF when compared with healthy control
- There is a decrease in posttreatment activity of masseter and orbicularis oris in patients with OSMF
- EMG can serve as a useful aid in detecting the involvement of the muscles of mastication and muscle of facial expression in patients with OSMF
- EMG can also serve as a useful diagnostic aid in assessing effect of the treatment on muscular activity in patients with OSMF.
Limitation of the study
- The sample size of the study group was small, that is, 30 patients
- Pretreatment and posttreatment EMG have not been correlated ultrasonographically to evaluate the changes in the muscle
- EMG is an expensive investigatory modality and it needs expertise for interpretation.
Therefore, a study with a larger sample size, using EMG and ultrasonography, to assess muscle hypertrophy is recommended to substantiate its role as diagnostic and prognostic tool in OSMF.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2]