| case report condyle seats upwards and forwards, and the mandi- bular plane rotates clockwise so that only the posterior teeth are in contact. When patients want to reach maximum intercuspation, they do so at the expense of the condylar position. The posterior teeth become the fulcrum, where the occlusal plane pivots, pushing the condyles downwards and backwards. When there is orthopaedic instability and the teeth are not in occlusion, the condyles are held in their stable musculoskeletal position by the elevator muscles, resulting in a very unstable occlusion. However, when the teeth are brought into occlusion, maximum inter- cuspation cannot be achieved with the condyles in a stable position. Therefore, the individual has to choose either to maintain a stable condylar position and occlude on a few teeth or to make the teeth contact in a more stable occlusal position, which would compromise joint stability. Therefore, in diagnosing and planning any orthodontic treatment, a complete vision of the patient’s problems is necessary to determine the ideal solution for each case. Diagnosis is a fundamental part of our specialty if we want to achieve all our goals, especially stability and lon- gevity. Our main goals are orthopaedic stability, TMJ health, dental and facial aesthetics, increased airway, optimal jaw dynamics with a vertical masticatory pattern, periodontal health, dental stability and longevity and of course patient satisfaction. In the case of orthopaedically unstable patients, a stable arc of closure must be achieved before starting any orthodontic treatment. Stabilisation is achieved with an occlusal splint, and once stabilised, this position must be maintained until the end of treatment to attain ortho- paedic stability. Splints must be worn 24 hours a day, seven days a week. We use a two-piece splint, and both parts are constructed at the same vertical dimension of occlusion. The anterior splint covers the six anterior teeth (incisors and canines), and the posterior splint is united by a palatal bridge and covers the premolars and molars. The anterior splint opens the bite and avoids posterior contacts, diminishing the muscular activity and restoring symmetrical function. By increasing the vertical dimen- sion, we obtain relaxation of the elevator and depressor muscles. Patients wear it during sleep, ideally for at least eight hours. This splint allows repositioning of the condyles upwards and forwards and harmonising of the neuromuscular system by eliminating clenching and parafunction. During the day, patients wear the posterior splint, allowing seating of the condyles, stabilisation of dental contacts and recovery of the true arc of closure. The two-piece splint is much better accepted by pa- tients, since it produces no aesthetic problems and thus encourages greater compliance.49 According to the literature, the main reason for using splints in our profession is to deprogramme the muscles, modify sensory input and reduce the electromyographic activity of the mandibular and cervical elevator muscles. Our splints also reduce hyperactivity and muscle pain to achieve occlusal stability and to stabilise the mandibular position, supporting the healing and remodelling process of the TMJ. Sletten et al. analysed the effect of depro- gramming splints in relieving 12 symptoms related to TMD (e.g. noises, locking of the mandible, clenching and grinding of the teeth, headaches and neck pain, earaches and tinnitus) and observed statistically signifi- cant improvements in 11 of the symptoms analysed.50 Nemes et al. concluded that treatment with occlusal splints followed by molar intrusion to eliminate the dis- crepancy between maximum intercuspation and stable condylar position (centric relation) seems to be an effec- tive method in the treatment of patients with TMD.51 They also saw improvements in the condylar morphology in comparing the CBCT scans pre- and post-treatment. On the basis of CBCT scans, Ok et al. also observed that treatment of TMJ osteoarthritis with stabilisation splints induced favourable bone remodelling on the anterior surface of condylar heads with degenerative condylar changes.52 Because treatment with splints seats the condyles upwards and forwards within the glenoid fossae and the mandible rotates clockwise, in most cases, only the posterior teeth will come into contact. It is at this time that we must change the occlusal plane with orthodontics to achieve orthopaedic stability, that is, coincidence of maximum intercuspation and stable condylar position. Two clinical cases of patients with TMD are presented in this article. Their condylar positions were first stabilised with splints, and they were then treated with the FAS Aligner System (FORESTADENT) using the true arc of closure, allowing us to achieve good aesthetics and occlusal function, which are the FACE treatment objec- tives (Fig. 1).53 Case 1 A 30-year-old female patient presented with the chief complaints of severe muscle and joint pain, open bite and tooth wear. She was treated orthodontically as a teen- ager with fixed appliances. Extra-orally, we observed slight mandibular asymmetry with deviation of the chin to the right, as well as lip incompetence, insufficient chin projection and a long face typical of a dolichofacial skel- etal pattern (Fig. 2). Intra-orally, she had an anterior open bite, retroclined maxillary incisors, moderate crowding in both arches, an asymmetrical arch form uneven gingival margins, a mandibular midline shifted to the right, abfrac- tions, gingival recession and wear facets (Fig. 3). The joint 60 aligners 2 2023