to evaluate effect of low-level laser therapy (LLLT) on mandibular condylar volume and position after treatment of Class II malocclusion with Twin Block (TB) functional therapy via cone beam computed tomography (CBCT).

Materials and methods: Twenty eight growing patients, 14 boys and 14 girls ranged in age 9-12 years, were randomly divided into control group (mean initial age 10.64±1.36 years) and laser group (mean initial age 10.55 1.45 years). All patients treated with TB appliance where Gallium aluminum arsenide diode laser applied in one group weekly around TMJ region for 12 sessions in three months with set parameters: continuous 635 nm, 50 mW, 4.5J/cm2, 45 seconds/ point, total dose per side 11.25J. CBCT were obtained before and immediately after TB therapy, in addition to routine orthodontic records. Changes in TMJ and skeletal variables were analyzed and compared within and between both groups.

to evaluate the effect of low-level laser therapy (LLLT) on mandibular condylar volume and position after treatment of Class II malocclusion with Twin Block (TB) functional therapy via cone-beam computed tomography (CBCT).

Materials and methods: Twenty-eight growing patients, 14 boys, and 14 girls ranged in age 9-12 years, were randomly divided into control group (mean initial age 10.64±1.36 years), and laser group (mean initial age 10.55 1.45 years). All patients treated with TB appliance where Gallium aluminum arsenide diode laser applied in one group weekly around TMJ region for 12 sessions in three months with set parameters: continuous 635 nm, 50 mW, 4.5J/cm2, 45 seconds/ point, total dose per side 11.25J. CBCT were obtained before and immediately after TB therapy, in addition to routine orthodontic records. Changes in TMJ and skeletal variables were analyzed and compared within and between both groups.

Inclusion Criteria:

• Skeletal Class II (ANB°> 5°) with the normal maxilla (SNA°=82°±4°) and retrognathic mandible (SNB°< 78°).
• Overjet greater than 5 mm.
• Minimal crowding in dental arches (≤ 3 mm).
• The lower incisors should be on average inclination or slightly retroclined.
• All the patients were in stages II and III based on the modified cervical vertebral maturation stages(CVMS) according to Bacetti et al.

Exclusion Criteria:

• Previous history of orthodontic treatment.
• Congenitally missing or extracted permanent tooth (except third molars).
• Posterior crossbites or severe maxillary transverse deficiency.
• Severe facial asymmetry determined by clinical or radiographic examination.
• Poor oral hygiene.
• Systemic diseases that may affect orthodontic treatment results.