Patients will receive pulsed high-intensity laser therapy in addition to conventional treatment

Patients will receive placebo high-intensity laser therapy in addition to conventional treatment

• Pulsed high-intensity laser therapy (HILT) will be applied 3 sessions per week for 8 weeks with pulsed emission (1064 nm), very high peak power (3 kW), a short duration (120-150 ms), and low frequency (10-40 Hz).The probe is fixed vertically at 90° to the most painful points while the patients sit on a chair and wear safety eyewear.
• Conventional treatment ( 3 days per week for 8 weeks).: in the form of
• Hot pad: It will be used over the temporomandibular joint (TMJ) for 5 minutes at the beginning of each session.
• Ultrasound therapy (US): it will be applied over the TMJ with pulsed intensity of 1.0 W/cm2 at a 1MHz frequency for 5 min/session.
• TENS: one electrode is placed over the TMJ and the other just above the mandibular angle. it will be applied with a low frequency of 50 HZ, tolerable intensity for 15 minutes.
• Exercise therapy: anterior, medial and lateral glide of the mandible. Each glide will be done 10-15 repetitions, 5-6 times in a session, 10 minutes as a total.

The surface electromyography device (sEMG) (MyoTrac Infiniti 2 Channel sEMG w/Rehab Suite & Continence Suite-T9855; Quebec, Canada) at 60 Hz and Infiniti software will be used to record masseter and temporalis activity before and after the treatment program.

patients will be instructed to clench to help the researcher to find the appropriate muscle location by their prominence. Pregelled and self-adhesive electrodes with 3 surface leads (2 recording, 1 reference) will be used. The electrode is placed over the anterosuperior to the angle of the mandible on both sides for recording masseter muscle, while for temporalis muscle, electrodes are placed above a line drawn from upper earline to canthus of the eye with interelectrode distance which is 8mm.

sEMG Signal Analysis: Mean, median frequency, SD, root mean square, minimum, maximum, and range of muscle activity (μV) will be calculated.

Visual analogue scale (VAS), a valid and reliable measure of pain intensity will be used to measure pain intensity for all participants in both groups before and after treatment. All participants will be asked to mark their pain level on a 10-cm line that corresponds to their pain intensity on the line between "0", representing "no pain", and "10", representing "the worst pain.

Flexible millimeter ruler will be used to measure mouth opening for all participants in both groups before and after the treatment. Mouth opening will be evaluated by asking the patient to open their mouth as wide as possible and measuring the distance between the edges of the frontal incisors with a ruler at the incisal edge of the maxillary central incisor that is the most vertically oriented and measured vertically to the labio-incisal edge of the opposing mandibular incisor to assess the pre-post therapy maximum mouth opening (MMO). Studies reported range has been as wide as 32-62 mm (for both sexes)

Arabic version of LDF-TMDQ will be used to assess the limitation of daily function in patients with temporomandibular dysfunction in both groups before and after the treatment program. It consists of 10 items. For each item, the subject chose any one of five levels on a numerical rating scale from no problem at all (0) to extremely difficult (4 points). The total score of the 10 items, ranging from 0-40 points, will be analyzed. Internal consistency of the total scores appeared to be good at 0.78 for the 10 items.