CATEGORY 76 AUSTRALASIAN DENTIST CLINICAL Introduction Temporomandibular disorders (TMDs) were classified in 1992 by Dworkin and LeResche into three major diagnostic groups within a research diagnostic criteria TMD model (RDC/TMD). These were: (I) muscle diagnoses, (II) disc displacements and (III) arthralgia, arthritis and arthrosis. (Dworkin and LeResche 1992). The Group I ‘Muscle diagnoses’ in the model was further subdivided into myofascial pain and myofascial pain with limited movement. Myofascial pain requires differentiation from other muscle disorders as mentioned by Dworkin and Le Resche 1992 and elaborated by Friction (Fricton 2007). The Group II ‘Disc displacements’ in the model was divided into three distinct groups aided by MRI diagnostic imaging, namely: (1) disc displacement with reduction, (2) disc displacement without reduction with limited opening and (3) disc displacement without reduction, without limited opening (Dworkin and LeResche 1992). The group III ‘Arthralgia, Arthritis, Arthrosis’ in the model detailed simple arthralgia as pain and tenderness of the joint capsule and/or synovium of either or both TMJ’s during palpation along with self-reported pain and coarse crepitus must be absent. They claimed osteoarthritis of the TMJ must include arthralgia and either or both coarse crepitus and radiologic signs of arthrosis. Osteoarthrosis of the TMJ was described as a degenerative disorder with radiologic signs of abnormal joint form and structure but without coarse crepitus (Dworkin and LeResche 1992). Poveda-Roda et al. 2012 examined 162 patients according to the RDC/TMD model and evaluated the amount of overlap between Groups I, II and III diagnoses. They found that a single diagnosis occurred 68.4%, while double diagnoses occurred 31.5% and triple diagnoses accounted for 3.7% of the cases (Poveda-Roda et al. 2012). Diagnostic imaging, using MRI and in the past arthrograms, have been instrumental in pinpointing the location of displaced discs for classification by Dworkin and LeResche (Dworkin and LeResche 1992) into their Group II disc displacement TMD model. When an MRI cannot be prescribed a clinician must consider a provisional TMD differential diagnosis between ‘a clinical diagnosed disc displacement’ and muscle diagnoses (Dworkin and LeResche 1992,Fricton 2007), and arthritic conditions (Dworkin and LeResche 1992). Disc displacement and treatment The laxity of supporting TMJ ligaments and their relationship with disc displacement was methodically evaluated by De Coster et al. 2005 using 24 Marfan syndrome and 18 Ehlers-Danlos syndrome subjects. Disc displacement with reduction occurred in 96.3% of the hypermobile group compared to 52.5% in a TMD control group. The study concluded that a positive relationship existed between generalised joint hypermobility and TMD with disc displacement (De Coster et al. 2005). Arthroscopic surgery for the treatment of internal derangement with persistent closed lock symptoms was performed with improved outcomes on 21 joints by Sanders 1986. Sanders claimed persistent closed lock occurs for the following reasons: ‘Disk and fossa surface stickiness (suction cup effect) and fibrillations along with synovial adhesions in the superior compartment appear to be the primary reasons a displaced disk does not reduce and a closed lock persists’ (Sanders 1986). Various interventions in the management of TMJ disc displacement without reduction was evaluated in a systematic review by Al-Baghdadi et al. 2014. The primary outcomes of TMJ pain intensity and maximum mouth opening were performed in 20 studies involving 1,305 patients. Interventions included: jaw exercises, education, self-management (exercises and medication), physiotherapy, TENS, active pulsed electromagnetic fields, iontophoresis, arthrocentesis, arthrography, auriculotemporal nerve block, TheraBite device, mandibular manipulation, open surgery, arthroscopy, and splint therapy. They concluded that the least invasive interventions of patient education, self-management and early mandibular manipulation were recommended for the initial management of ‘closed lock’ (Al-Baghdadi et al. 2014). The precise protocol for the management of TMDs remains unresolved. Although conservative management opposed to surgical management appears to be the preferred starting point. A systematic review by Manfredini et al. 2017 of 25 papers found a ‘lack of clinically relevant association between TMD and dental occlusion’ (Manfredini et al. 2017). This included questioning whether the use and effectiveness of occlusal splints or oral appliances was justified for the treatment of TMDs and bruxism (Klasser et al. 2010,Major and Nebbe 1997, Manfredini, Lombardo; et al. 2017). However, Darveniza in 2022 found using ‘Fully Protective Occlusal Splints’ with ‘Formal Occlusal Splint Therapy’ (Darveniza 2022, Darveniza 2022, Darveniza 2022) and concurrent ‘Full Counselling’ (Darveniza 2023, Darveniza 2023) of 200 TMD patients that a mean improvement of 71% occurred at a mean follow-up period of 6.1 years. Full occlusal therapy The author has used ‘Full Occlusal Therapy’ (Darveniza 2023) as the starting point for conservative management of TMDs since 1981. Occluso-mandibular analysis (Darveniza 2023, Darveniza 2022) and bio-designing lateral guidance/restriction (Darveniza 2001) for brachyfacial and normal patients since 1988. For a brachyfacial and normal skeletal patients with poorly positioned canines Darveniza reported, in 2001, how to bio-design restorative anatomical shapes to create A preliminary investigation of 200 TMD patients treated using ‘Full Occlusal Therapy’ with case studies. By Dr. Michael Darveniza MDSc PhD (Qld) FRACDS, Prosthodontist: Lismore, New South Wales
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