Laser Therapy on TMJ Disorders After Head and Neck Cancer.

Impact Of High Intensity Laser Therapy On Temporomandibular Joint Disorders After Head And Neck Cancer.

Temporomandibular disorder (TMD) is a term describing musculoskeletal conditions of the face, jaw and temporal regions. TMD is frequently associated with pain and/or dysfunction such as impaired jaw function, pain in the temporomandibular joint (TMJ), muscles and/or related structures, and associated headaches. The aetiology of TMD is multifactorial and complex.

It is known that one cause of TMD symptom development is treatment for head and neck cancer (HNC). The main treatment modalities for HNC include radiotherapy (RT) with or without chemotherapy and surgical intervention, either as a single therapy or a combination therapy. In the head and neck region, the anatomical structures are necessary for essential functions such as speech, swallowing, breathing, smell, and taste. The treatment of head and neck tumours may frequently impair some of these functions, which may result in pain, oral dysfunction, and impaired health-related quality of life. High intensity laser therapy (HILT) is a non-invasive and painless treatment method. The latest studies have reported the beneficial effects of neodymium-doped yttrium aluminum garnet (Nd: YAG) laser therapy in patients with pain. The advantage of HILT over low level laser therapy (LLLT) is that HILT is able to penetrate and stimulate wider and/or deeper areas; thus, considerably more energy may be transmitted to tissue during HILT therapy compared to LLLT.

patients will receive Nd: YAG with wavelength 1064 nm, peak power 3KW, energy density 360-1780 mJ/cm2, a short duration 120-150 micro sec, a mean power 10.5 W, a low frequency 10-40 HZ, a duty cycle of 0.1%, a probe diameter of 0.5 cm and spot size of 0.2 cm2. The treatment will be applied into 3 phases in each session. In addition to the traditional physical therapy exercise program (passive and active ROM exercises, stretching and strengthening exercises) for 20 minutes, total session time is 35 minutes, 3 days/ week for 4 weeks.

passive and active ROM exercises, stretching and strengthening exercises for 35 minutes, 3 days/ week for 4 weeks.

patients will receive placebo HILT including the same treatment as in group A but the laser device will be turned off.

It will be measured by visual analogue scale. It starts with no pain at the left side and gradually increasing pain towards the end of the line at the right side (0-10) and high scores indicate greater pain.

Surface electromyography (EMG) will be used to evaluate the strength of the masseter and anterior temporal muscles

It will be measured by jaw functional limitation scale-20. It has a score range of 1 to 200, and high scores indicate worsening jaw function.

By using the Oral health Impact Profile consisted of 7 different domains (functional limitation, physical pain, psychological discomfort, psychological disability, physical disability, social disability, and handicap). Each domain was assessed by two questions, scored using a 5-point Likert scale (0 = never to 4 = very often). The total score was derived by a summing of the domain scores, it can range from 0 to 56. A higher score indicates a poorer quality of life.

Inclusion Criteria: Patients with temporomandibular joint disorders (myofascial pain, trismus and limitation of ROM) after head and neck cancer, patients will be diagnosed by an experienced oral and maxillofacial surgeon. Patients with 20 to 60 years old. 6 months after ending radiotherapy. Exclusion Criteria: Patients with implants. Current metastasis. Continuing radiotherapy. Pregnant females. Sensitivity to phototherapy. Bells palsy. Subjects with disk displacement, arthralgia or osteoarthritis at TMJ. Subjects who received analgesics or antidepressants.