Abstract: Objective: To analyze the changes and characteristics of jaw growth in adolescent patients with temporomandibular joint disc displacement. Methods: 32 adolescent patients with unilateral temporomandibular joint disc displacement were involved in this study. CT scan were performed and the data was input in to Surgicase5.0 software for three-dimensional measurement. The upper/lower mandible markers and reference planes were set up to measure horizontal, vertical and sagittal growth, and to compare the difference between two sides of jaws. Statistical analysis was made by SPSS 16.0. Results: The development of the mandible in the side with TMJ disc displacement was smaller in all directions than those in the contralateral side. All of the patients showed mandibular deviation to affected side. Distance of point Gn to SAG plane ranged from 0.72 to 12.37mm, the average was 4.72 +/- 3.41mm; the ipsilateral mandibular body length was shortened compared to the normal side (P<0.05); the discrete distance of points Go and Co to SAG plane were shorter than those of the contralateral side (P<0.001); mandibular incisor point (Li) deviated to the side with disc displacement at a range of 3.44 +/- 2.72mm, overtook maxillary incisor point (Ui), with a date of 1.19 +/-0.63mm(P<0.001); transverse diameter of condyle was smaller in the side with disc displacement (P<0.001). Conclusion: Temporomandibular joint disc displacement in adolescence was closely related to the occurrence of asymmetric maxillofacial deformity and presented a consistent characteristic. Key words: three dimensional changes, adolescent , temporomandibular joint, disc displacement

Key words: adolescent temporomandibular joint disc displacement three dimensional