Myofascial pain is one of the common symptoms in patients with temporomandibular joint disorders. Occlusal splint use, trigger point injections and the combination of this two methods are primary treatment options. Patients were divided into 3 groups and this three treatment was applied. We aimed to investigate the clinical and ultrasonographic effects of the treatments. Patients in the treatment groups were reexamined at 1st and 3rd months, and their clinic and ultrasonographic records were repeated. 16 healthy volunteers were also included in the study. No treatment was applied, only clinical and ultrasonographic records were taken once.

48 patients who had myofacial pain and were diagnosed with according to Diagnostic Criteria for Temporomandibular Disorders were included in the study. There were 16 patients in each group. Group 1 was treated with occlusal splint, Group 2 was treated with occlusal splint and masseter muscle lidocaine injection, Group 3 was treated with masseter muscle lidocaine injection and Group 4 consisted of healthy volunteers. Visual analogue scale used for pain evaluation. Also, maximum mouth opening, lateral and protrusion movements of all groups were measured before any treatment. Masseter muscle volume was evaluated by ultrasonography whereas masseter muscle elasticity was evaluated by elastography before the masseter muscle lidocaine injection and occlusal splint treatment. In Group 2 and Group 3, masseter muscle injections were repeated two more times, on 7th and 14th days. Clinical and ultrasonographic measurements were repeated at 1st and 3rd months.

Inclusion Criteria:

• Indication of muscle pain according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) diagnostic decision tree,
• Having minimum three trigger points in the masseter muscles on palpation (active or latent),
• No medical or surgical treatment for temporomandibular joint in the last 3 months,
• No history of occlusal splint treatment,
• Not had a masticatory muscle injection or dry needling before,
• Absence of active caries and pulpal lesions,
• No missing teeth other than the third molar,

Exclusion Criteria:

• Intra-Articular Disorders or Degenerative Joint Disease indication according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) diagnostic decision tree,
• Presence of active infection in the masseter trigger point area,
• Being in the mixed dentition period,
• The patient has used an occlusal splint before,
• Known allergy to local anesthetics,
• Having a needle phobia,
• Presence of congenital head and neck deformity,
• Having systemic joint disease,
• Presence of cardiovascular disease, thyroid disease, diabetes, hypertension, renal failure, isolated muscle disease, rheumatological and neurological disease,
• Having a history of trauma in the head and neck region in the last 2 years,
• Presence of malignancy or having undergone head and neck radiotherapy/chemotherapy in the last 2 years,
• Presence of bleeding disorder,
• Use of analgesic, corticosteroid and anticonvulsant drugs,
• Presence of fibromyalgia diagnosis,
• Being treated by a neurologist for neurological disorders and/or neuropathic pain and/or headache,
• Pregnancy or lactation,
• Having a known psychiatric disorder and using antidepressants in the last 6 months,
• Having drug and/or alcohol addiction,
• Being under active orthodontic treatment.