|Year : 2016 | Volume
| Issue : 2 | Page : 68-72
Effectiveness of transcutaneous electrical nerve stimulation to relieve the tensed masticatory muscle: A retrospective study
Nisheeth Saawarn1, Preeti P Nair1, Sana Noor Siddiqui2, Shiba K Neelakantan3, Annette Bhambal1, Pearl Helena Chand1, Harshkant P Gharote1
1 Department of Oral Medicine and Radiology, People's College of Dental Sciences, Bhopal, Madhya Pradesh, India
2 MDS, Oral Medicine and Radiology, Bhopal, Madhya Pradesh, India
3 Ibn Sina National Medical College, Jeddah, Saudi Arabia
|Date of Web Publication||6-Jan-2017|
Pearl Helena Chand
People's College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Myositis, a painful inflammatory condition of masticatory muscles, characterized by protracted local muscle soreness or myofascial pain, is most commonly caused by a source of nociception found in the muscle tissues having origin in central nervous system. Various therapeutic modalities used are pharmacologic, physical, or psychological. Transcutaneous electrical nerve stimulation (TENS), a physical sensory stimulant therapy using high frequency and low-intensity electric current stimulates the nonnociceptive A-beta cutaneous afferents that activate the pain inhibitory mechanism. Its action is immediate with 50%-70% analgesic effect and induces few or no after effects.
Purpose of Study: The objective of this retrospective analytical study was to assess the efficacy of TENS therapy in patients suffering from myositis.
Materials and Methods: The clinical data of the patients of myositis treated with TENS during 2011-2012 in OPD of a dental school in India were retrieved from department archives and analyzed. In all these patients, severity of pain was assessed on visual analog scale at baseline and at every follow-up visit. The data were analyzed statistically using unpaired t-test.
Results: Out of 22 patients treated, 18 showed significant improvement while three were unresponsive and in one patient the condition deteriorated.
Conclusions: TENS may be an effective, economical, and easy to use therapy with minimal side effects in patients suffering from myositis.
Keywords: Electroanalgesia; masticatory muscle; myofascial pain; myositis; orofacial pain; temporomandibular joint dysfunction syndrome; transcutaneous electrical nerve stimulation
|How to cite this article:|
Saawarn N, Nair PP, Siddiqui SN, Neelakantan SK, Bhambal A, Chand PH, Gharote HP. Effectiveness of transcutaneous electrical nerve stimulation to relieve the tensed masticatory muscle: A retrospective study. Indian J Multidiscip Dent 2016;6:68-72
|How to cite this URL:|
Saawarn N, Nair PP, Siddiqui SN, Neelakantan SK, Bhambal A, Chand PH, Gharote HP. Effectiveness of transcutaneous electrical nerve stimulation to relieve the tensed masticatory muscle: A retrospective study. Indian J Multidiscip Dent [serial online] 2016 [cited 2017 Sep 20];6:68-72. Available from: http://www.ijmdent.com/text.asp?2016/6/2/68/197746
| Introduction|| |
Any painful condition persisting for a long duration causes trouble in one's daily routine and poses great discomfort and uneasiness. One such condition is myositis, which is described as a painful inflammatory condition of muscles, characterized by protracted local muscle soreness or myofascial pain and is most commonly caused by a source of nociception found in the muscle tissues having origin in central nervous system.
Masticatory muscle pain is assumed to be associated with a variety of biophysiological risk factors. , It may arise from a condition which may force a patient to develop unilateral chewing habits such as overcontoured crowns, high points in restorations, missing teeth, and periodontally weak teeth.  The condition may also rarely occur due to viral or bacterial infections.  Common signs and symptoms of myositis include the presence of constant dull-aching pain of myogenous origin, limited mouth opening, and tenderness of muscles of mastication on palpation. 
Once the condition is diagnosed correctly, it is important to treat it to decrease musculoskeletal load and pain, to restore normal joint function (strength, movement, and resistance), and to help the patient to return back to the normal daily activities. In most cases, masticatory muscle pain can be managed successfully. In a considerable number of patients, however, the pain persists over a long period despite therapeutic interventions. In such cases, understanding of the underlying neurobiological background of acute and chronic pain may help in therapeutic decision-making and evaluation of the therapeutic effects. 
Various treatment modalities which can be used are supportive therapy (such as electromyographic biofeedback, cognitive therapy, and home care instructions), pharmacotherapy (such as analgesics, corticosteroids, muscle relaxants, and antidepressant), physical therapy (such as thermal therapies, ultrasound, trancutaneous electric nerve stimulation [TENS], and acupuncture). ,,, In addition, occlusal corrections are important in conditions where occlusal disturbances may be one of the etiological factors. ,, Out of these, TENS is one of the effective modes of treatment which can be used alone or as an adjunct to the other treatment modalities.  Various studies done in past have shown efficacy of TENS in treatment of several conditions such as myofascial pain dysfunction syndrome, joint pain, and disc displacement among others. ,
TENS has proved to be beneficial in several myofascial pains but there are very few studies showing its usefulness in myositis of masticatory muscles. Hence, a need was felt and this study was carried out to determine its effect in the management of pain in myositis of masticatory muscles and to compare the percentage relief obtained in pain intensity at different intervals.
| Materials and Methods|| |
This retrospective study was carried out in the outpatient department of a dental school in India. The clinical data of patients diagnosed with myositis of masticatory muscles using research diagnostic criteria  and treated with TENS in the past 2 years were retrieved from the archives of the department, tabulated, and analyzed statistically using unpaired t-test. The patients who had limited mouth opening and temporomandibular joint (TMJ) pain were not included in the study. The study group comprised a total of 22 patients of either sex between 19 and 70 years of age.
In all these cases, conventional TENS therapy with low-intensity and high-frequency at the site of pain had been given with pulse width of 60-120 pulse/s at pulse rate 6-8 mA for 15 min. The therapy was given unilaterally or bilaterally depending on the side/sides affected and the average recall interval was within the range of 1-2 days on an average. Postoperative pain relief had been recorded as percentage relief from the baseline.
| Results|| |
Out of 22 patients, 10 were male (45.4%) and 12 were female (54.5%) with a mean age of 34.4 years [Table 1]. Masseter alone was involved in 6 (27.2%) patients, lateral pterygoid alone was involved in 2 (9%) patients, masseter with lateral pterygoid was involved in 6 (27.2%) patients, masseter with temporalis was involved in 4 (18%) patients, masseter with medial pterygoid was involved in 1 (4%) patient, masseter with temporalis and lateral pterygoid was involved in 2 (9%) patients, masseter with temporalis, lateral pterygoid, and medial pterygoid was involved in 1 (4%) patient [Graph 1 [Additional file 1] ], [Graph 2 [Additional file 2] ] and [Graph 3 [Additional file 3] ]. Thus, masseter was the most commonly involved muscle affecting 20 (90.9%) patients and medial pterygoid was the least commonly involved affecting only 2 (9.09%) patients [Graph 2].
On analysis of pain relief, there was an increase in mean percentage relief from 20.3% at first visit to 54.6% by the end of fourth visit [Table 2]. On comparing the relief in pain intensity between various visits, it was found that the relief in pain had increased from 33.3% between first and second visit to 83.2% between first to fourth visit [Table 3], which was statistically significant (P < 0.05).
|Table 2: Mean percentage relief in pain for every posttherapy visits for initial four visits from baseline |
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|Table 3: Comparison of percentage relief in pain intensity at various visits |
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In the present study, in 17 out of 22 (77.3 %) patients, there was more than 80% relief in pain by the end of eighth visit and out of which, 5 (22.7%) patients were completely pain free; however, there were four patients with little or no response to the treatment [Table 4].
| Discussion|| |
Myositis exhibits common signs and symptoms such as constant dull aching myogenous pain, limited mouth opening, and tenderness of muscles of mastication, which is also seen in other myofascial pains and makes it difficult to get correctly diagnosed. , Once diagnosed, it requires appropriate management. After diagnosis, the next area of concern is the pain quantification. Although this can be done through the visual analog scale, the individual painful behaviors are different.  The condition, though sometimes self-limiting, can turn into a chronic one. In either situation, it needs to be managed appropriately, but especially in the chronic conditions. 
Various treatment modalities used are supportive, pharmacological, and physiotherapy, which can be used either alone or in combinations. Pharmacological approach had its complications associated with the adverse effects of medications if used for a prolonged period. Similarly, various physical and supportive therapies too have their limitations such as they may require professional assistance and skills. TENS is one such physical mode of therapy which may be a quite useful and sometimes a great boon to the patients undergoing treatment. 
By broad definition, "TENS is anything that delivers electricity across the intact surface of the skin to activate underlying nerves."  Earliest written records show that its use came from the Greeks. Use of TENS in dentistry was first described in 1967 by Shane and Kessler.  The use of TENS is based on several interrelated theories on the mechanisms of pain transmission and blocking of those mechanisms. The first of these theories was the gate control theory by Melzack and Wall in 1965 which suggests that stimulation of thick, myelinated, sensory A-fibers by TENS blocks the impulses of thin pain-modulating C-fibers and closes the gate to pain signals at their level of entry into spinal cord. ,,
Second theory is related to endogenous release of morphine-like substances having analgesic properties after electrical stimulation. A third theory is related to automatic and involuntary contraction of muscles by TENS which causes repetitive depolarization of skeletal muscle at a rate <100/min in the presence of an adequate supply of high-energy phosphate which reduces fatigue contracture. Furthermore, mild rhythmic muscle movement increases the local circulation of blood and lymph, which reduces the interstitial edema and accumulation of noxious tissue metabolites. ,,
TENS has advantages such as it is noninvasive, has no adverse effects on prolonged use, is comparatively economical, patient may use it on his own without any professional assistance, has no potential to cause allergy, and is a swift method of analgesia. ,, In general practice, it is being used for abdominal pain (diverticulosis, postoperative pain, dysmenorrhea), back pain, upper, and lower extremity pain. In head and neck region, it is commonly used for migraine, trigeminal neuralgia, acute and chronic myofascial pain, TMJ pain, atypical facial pain, headaches, postherpetic neuralgia, neuritis, etc. ,,,
TENS is contraindicated in cases of hypertension, hypotension, cardiac arrhythmias, pacemakers, cochlear implants, cerebrovascular disease, seizures disorders, brain tumors, or neurological disease involving the head and neck, abnormal bruising or bleeding disorders, pregnancy, patients with undiagnosed dental pain, patients having skin lesions or facial abrasions, especially at the site of electrode placement. ,
In our institute, we have been using TENS with satisfactory results in cases of TMDs and myofascial pain of masticatory muscles. We decided to analyze the data of the patients of myositis so far treated with TENS. In this retrospective study by the end of the fourth postoperative visit, the mean percentage relief in pain has increased to 54% from 20.3% in the first postoperative visit. Further, by the end of eighth follow-up visit, 5 out of 22 patients reported 100% relief from pain.
The efficacy of TENS therapy in reducing myofascial pain observed in our study is similar to the observations made by List and Helkimo  and Mehta et al.  List and Helkimo reported 57% reduction in pain following TENS therapy in patients with myogenic craniomandiublar disorders.  Mehta et al. too reported 57% reduction in pain following TENS therapy in patients with joint or muscle pain. 
However, Wessberg et al. and Geissler et al.  reported higher success rates. Wessberg et al. observed 95% success immediately after TENS therapy, which was consistent with 86% relief even a year after the therapy.  Geissler et al. reported relief in 63.6% of patients with joints and muscle pain after TENS therapy compared to 54% in the present study. 
The differences observed between these studies and the present study could be due to the differences between the sampling, biological, and psychological components of the myofascial pain, individual pain behavior as well as stimulation parameters used for the TENS therapy.
| Conclusions|| |
The results of the present study as well other studies reported in the scientific literature suggest that the TENS is an effective and safe therapeutic modality for the myositis and should be used frequently whenever indicated either alone or in conjunction with other therapeutic modalities for a successful management of myositis and TMD.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]