Nd-YAG Laser Versus Epidermal Growth Factor For Myogenic Tempromandibular Disorder.

Background: Tempromandibular disorders (TMDs) form a public health issue and are considered the second most common musculoskeletal problem (after chronic lower back pain) causing pain and disability. Myogenic TMD is one of the commonly prevalent TMDs with unclear pathophysiology. Central and peripheral sensitization are thought to play an evident role in development of myogenous TMD. Many treatment modalities have been proposed to eliminate pain, improve function and quality of life. Laser photobiomodulation has gained popularity in pain therapy and in treatment of chronic painful musculoskeletal disorders, among which are TMDs. Piano level laser therapy (PLLT) enables delivering different high intensities using large spot sizes and can be considered beneficial in the treatment of painful myogenic TMD.

Epidermal growth factor (EGF) has been found to repair muscle damage and increase muscle quality through direct promotion of proliferation and differentiation of muscle cells in addition to regulating the inflammatory response. EGF can be another minimally invasive treatment modality for chronic painful myogenic TMD. Glutamate and nerve growth factor (NGF) are considered neuropeptides associated with pain and hyperalgesia.

They have been related to painful TMD and have also been detected in saliva of patients suffering from chronically painful conditions including TMDs. Aim: The present study aims to evaluate and compare the effectiveness of Piano level laser therapy using 1064nm Nd-YAG laser and intramuscular EGF injection in pain alleviation, improvement of function and quality of life in patients suffering from myogenic temporomandibular disorder. The impact of these treatment modalities on levels of salivary glutamate and nerve growth factor pain mediators will also be investigated. Materials and Methods: A randomized clinical trial will be carried out on 30 patients suffering from chronic painful myogenic TMD based on diagnostic criteria for temporomandibular disorders (DC/TMD). Group I (n=15 patients) will be treated using 1064 nm Nd-YAG Laser: in 4 combined (cold=2W, warm=5W) laser therapy sessions (once/week) using stamping technique on masseter and temporalis muscles. Group II (n=15 patients) will be treated by intramuscular injection of EGF in masseter and temporalis muscles.

Inclusion criteria

• Patients, both males and females, 20 years and older will be included in this clinical trial.
• Patients suffering from myogenic TMD (myogenic TMD/ Myofascial pain without referral/ Myofascial pain with referral) based on Diagnostic criteria for diagnosis of Tempromandibular joint disorders (DC/TMD) criteria (1)
• Patients suffering of unilateral or bilateral chronic pain (> 3 months duration) related to masseter and temporalis muscles (29)
• Patients that have not responded to conservative modes of treatment (analgesics, muscle relaxants, fomentation, splints ect.).

Exclusion criteria

• Patients suffering from any condition that could alter pain sensitivity; neurological diseases, pain of dental origin, pregnancy or lactation, high blood pressure, diabetes mellitus, rheumatic inflammatory disease, fibromyalgia, obstructive sleep apnea, skin infection over injection areas related to masseter and temporalis muscles, and restrictions for the use of laser (pacemakers) (6, 20, 30) 2. Participants on medications that can affect pain sensitivity and pain perception; anticoagulants, analgesics, antidepressants during the last 2 weeks before the study (6, 20) 3. Smokers or those with conditions that could affect saliva collection or composition; hyposalivation, poor oral hygiene, periodontitis and oral mucosal diseases