Aim of the study
This study was conducted to evaluate the three dimensional changes in the TMJ after the maxillary protraction using face mask therapy.

Material and Methods
Eighteen growing patients (ages ranged from 8-11 years) were included in the current study. All patients manifested features of skeletal class III due to maxillary deficiency. A Petit-type facemask was used for all patients and was attached intraorally to a fixed labiolingual appliance through extraoral elastics . A cone-beam CT scan had been applied for each patient before the start of the treatment and after 10 months. The three-dimensional (3D) temporomandibular joint measurements included: 1) anterior fossa line inclination, 2) posterior fossa line inclination, 3) anterior joint space, 4)posterior joint space,5) medial joint space, and 6) superior joint space.
Results
Regarding Anterior Joint space : measurements after using a facemask appliance were significantly higher than before (as P<0.05) ,while regarding Posterior and superior Joint spaces : measurements after using a facemask appliance were significantly lower than before (as P<0.05)

Conclusion
Facemask therapy for maxillary protraction in management of skeletal class III produced:
1- Decrease in both posterior and superior joint spaces ,while increase in the anterior joint spaces.
2- Bone remodeling in the glenoid fossa causes upward and backward displacement of the condyle.