A Clinical Trial Study to investigate the potential performance of BTXA on masseter muscle on patient with nocturnal bruxism and to check the pain scale and share this clinical experience.

Experimental group we will use BTX-A administration group. All patients (Male/Female) with bruxism associated with chronic pain in masseter muscles bilaterally participated in this study. The patients age 18-60 years. According to the diagnostic grading system of bruxism all subjects will have an assessment including a bruxism questionnaire (i.e., oral history taking with specific focus on bruxism habits) plus a clinical examination to evaluate bruxism signs and symptoms.

Inclusion Criteria:

1. Moderate to severe pain in relation to the masseter muscles and TMJ area related to bruxism during clinical examination.
2. Aged 20-60 patients.
3. Tooth-grinding sounds corroborated by family members or caregivers.
4. Cases where bruxism resulted in occlusal surface attrition of posterior teeth

Exclusion Criteria:

1. pain in the orofacial region,
2. insomnia,
3. known botulinum toxin allergy,
4. pregnancy,
5. neuromuscular disease,
6. bleeding disorders,
7. antibiotic therapy,
8. pulmonary disease that produced coughing during sleep,
9. infectious skin lesion at the site of the injection.