Journal of Craniomandibular Function, 04/2022

Aim: The present study is part of an extensive investigation on the positions and distances of the mandibular condyles. We wanted to know if and how the positions of the condyles in centric relation (CR) vary from each other using different CR records. Materials and methods: The condylar positions in CR were repeatedly recorded by four licensed colleagues on 81 stomatognathically healthy, fully dentate subjects with six different types of CR records. The maxillary casts were mounted in Dentatus articulators after individual facebow transfer, and the mandibular casts were mounted with a central-bearing point (CBP) registration on the tip of the Gothic arch. From three registrations of the centric condylar positions with each of the six registrations, we built mean values with which the comparative calculations were made. Results: The median spatial distances of the condylar positions between the CBP and all the other CR records were 0.73 ± 0.24 mm (0 to 3.19 mm). The spatial median values between the condylar positions of the different CR records ranged from 0.48 to 0.79 mm. Statistically, the positions of almost all types of registrations were slightly different from each other. Conclusions: Different CR records reproduce slightly different positions of the mandible, which is especially true for the CBP registration, whereas reproducibilities and standard deviations between the registrations are similar. The unrefined wax wafer registrations using bimanual manipulation according to Dawson have proved particularly successful with regard to precision and time requirements, as has the CBP registration with regard to the condylar position. Keywords: variation of centric relation registration, centric relation, centric relation records, Lauritzen grip, Dawson grip, bimanual manipulation, frontal jig, wax wafer, acrylic wafer, registration material

Objective: The aim of the present randomized controlled trial was to investigate whether a self-managed home exercise program is equivalent to relaxation splint therapy in terms of pain reduction during the initial phase of treatment of temporomandibular disorders (TMD). Materials and methods: 32 patients were enrolled in the study and randomly assigned to relaxation splint or home exercise therapy groups, respectively. The former group received relaxation splints fabricated to the patient’s jaw position in habitual occlusion with anterior-canine guidance and occlusal surface adjustment. The home exercise group was given a copy of the ‘Oral Physiotherapy’ DVD and instructed to perform the exercises demonstrated on the DVD three times a day. Results: After 4 weeks of treatment, both groups showed significant improvement in the outcome measures of pain, performance impairment, and number of sites with pain on palpation. The target of at least 30% pain reduction was achieved by 62.5% of patients in the relaxation splint group and by 68.8% of those in the home exercise group. Comparative analysis showed no clinically significant difference between the two groups (P > 0.05) and no inferiority of the instructional DVD compared with splint therapy for any of the outcome measures. Conclusion: The findings demonstrate that self-management of TMD pain by means of home physiotherapy exercises is as effective as relaxation splint therapy. Keywords: clinical trial, temporomandibular disorders, TMD, relaxation splint, physiotherapy, self-management

Objective: In the present study, a correlation between skeletal class (SC) and retrocranial condylar displacement in clinically mimicked bruxism function in condylography was examined. First of all, it was assessed whether subjects with SC II, due to their anatomy, had a greater predisposition for condylar displacement above a given pathologic threshold than subjects with SC I or SC III. Other parameters such as age and gender in connection with SC were also evaluated. Materials and methods: Condylographies (on an individual hinge axis) of 385 retrospectively selected subjects were evaluated in correlation with cephalometric measurements, and a cluster analysis was performed. Results: A connection could not be established between pathologic displacement of the condyle under clinically simulated bruxism function and SC. Half of the subjects examined showed a potentially pathologic displacement of the condyle under bruxism function. Conclusion: The results of the cluster analysis and the lack of correlation between condylar displacement above a given threshold and SC indicate a complex etiology, with a rather multifactorial genesis of the functional disorders of the temporomandibular joint. Keywords: temporomandibular dysfunction, condylar displacement, condylography, bruxism, skeletal classes