# An Orthodontic Treatment Case of a TMD Patient with Maximly Posterior Intrusion Using TsADs
## 2 Materials and Methods  
### Case Report  
A 27-year-old female patient complained about her retruded chin position. She had suffered from jaw pain since her early teens and had started to have specific joint pain in her left TMJ area when she opened her mouth starting a few months ago. In the clinical examination, clicking sounds were heard on both of her TMJs when the patient opened her mouth. The patient had lip incompetency and showed a convex profile with facial asymmetry in which her chin point deviated to the right. An intraoral examination found moderate maxillary and mandibular crowding with an 11.5 mm overjet and an 0.5 mm anterior open bite. She had Class II canine and molar relationships on both sides, and her dental midline in the mandibular arch deviated 3 mm to the right. From the panoramic radiograph, the condylar heads on both sides of TMJ were found to be significantly flattened. The lateral cephalometric analysis indicated a skeletal Class II pattern (ANB = 11.5\({}^{\circ}\)) with a hyperdivergent growth pattern (SN-MP = 48.0\({}^{\circ}\)). However, the saddle angle was found to be in the normal range, and the mandibular body was sufficiently developed compared with the anterior cranial base length, while the ramus height was short compared with the posterior cranial base length, which suggested that any deformation of the TMJ structures might have had an influence on these skeletal features rather than the patient's sheer growth pattern (Figure 1; Table 1). Figure 1: Pretreatment records: (**a**) facial and intraoral photographs, (**b**) lateral cephalogram, and panoramic radiograph. Since the patient presented with signs and symptoms of TMDs, the position of the mandible needed to be evaluated, so her dental models were mounted on a semi-adjustable articulator (SAM III; SAM Praezision-stechnik GmbH, Munich, Germany) [10]. The mandibular position indicator (MPI) was applied to determine the reliability of the patient's jaw positions. MPI data was used to evaluate the centric-related occlusion (CRO)-maximal intercuspal position (MIP) discrepancies at the joint level. The MPI measurements indicated a 2.2 mm (left side) and 1.3 mm (right side) downward condylar distraction (Figure 2a). Based on this diagnostic data, we concluded that the patient's mandible was in an unstable position, and therefore, her occlusion was not reliable enough to establish a definitive orthodontic diagnosis. To relieve pain that had been persistent in her TMJ area and to identify the stable condylar position of the mandible, a stabilization splint was suggested, an option which she accepted. A stabilization splint was fabricated on the SAM III articulator, and the patient was instructed in full-time use (Figure 2b). The splint was checked on a regular basis and adjusted to maintain a targeted occlusal scheme, a mutually protected occlusion. The stabilization splint played its role in eliminating the protective co-contraction of the surrounding masticatory muscles, and it led to an orthopedically stable joint position of the mandible. After a few weeks of the splint therapy, the pain in the patient's TMJ was reduced, but she was instructed to continue using the splint for weeks for the surrounding muscles to adapt to the TMJ structures. When we were convinced that her mandibular condyles were seated in their stable position based on MPI data and relieved TMJ symptoms, she was re-diagnosed for active orthodontic tooth movement. Her mandible was rotated clockwise as the condyles were seated into the most forward and uppermost positions, resulting in an increased anterior open bite (\(-1.5\) mm) and a more severe skeletal Class II pattern, with a steeper mandibular plane (ANB, \(12.5^{\circ}\); SN-MP, \(50.0^{\circ}\)) (Figure 2c,d; Table 1).