Journal of Craniomandibular Function, 04/2019

Different concepts are used for the analysis and transfer of mandibular movements to virtual or conventional articulating systems. Some common procedures and analyses include the determination of the terminal hinge axis. However, despite the widespread use of different methods for hinge axis determination, very little information on the applicability and quality of these methods is currently available in the literature. The aim of this study was to provide an overview of the methods already being applied and to search for novel algorithmic methods, comparing them with respect to achievable accuracy and implementation. This comparison was based on new extensive computer simulations, where the influence of measurement noise on the result of the hinge axis position could be investigated. The assumptions used for the simulations were set so that the conditions allowed for the most accurate hinge axis determination: this comprised a pure rotation during mouth opening, within an incisal pathway of 15 mm, a measurement accuracy of 50 µm, and an optimal positioning of the entire measurement setup. The results of the computer calculations show that the best accuracy can be guaranteed by the novel least squares method, introduced in this article for temporomandibular joint (TMJ) measurements. Additionally, only methods tracking two and more (iterative or parallel) independent markers or equivalent jaw position measurements provide enough information for reliable accuracy. Using actual technical equipment, the highest accuracies can be achieved in a TMJ-near measurement setup. However, even in that best-possible setup, the error of hinge axis determination cannot be expected to be less than ±1 mm. For a better characterization of actual electronic recording systems, manufacturers need to provide more insight into the evaluation processes. Keywords: terminal hinge axis, jaw tracking, temporomandibular joint, accuracy, computer simulation

Background: The acquisition and evaluation of psychosocial patient characteristics is particularly difficult during the initial diagnosis of patients with temporomandibular dysfunctions (TMDs). The aim of this study was to evaluate a newly developed evaluation aid for psychosocial questionnaires. Materials and method: Patients (n = 30) with TMD complaints presented themselves for examination to students in the clinical stage of the study of dentistry and were examined according to physical and psychosocial criteria. In order to record the localization and chronification of pain and the characteristics of anxiety, depression, and the tendency to non-specific physical complaints, patients completed questionnaires and transferred the data to an evaluation sheet. Finally, the students evaluated the practicability of the evaluation sheet and assessed its usability in daily dental practice. Results: The survey of users (n = 30) showed that 60.0% of the students found the evaluation of the psychosocial questionnaires using the evaluation form easy, 23.3% assessed the use as partly difficult, and 16.7% as difficult. A total of 90.0% of the participants would use the questionnaires and the evaluation form in their future dental practice. Conclusion: The use of questionnaires in combination with a summarizing evaluation aid enables a user-friendly initial diagnosis in TMD patients. Keywords: pain, depression, anxiety, somatization, axis II, DC/TMD

Many different opinion-based diagnostic reporting systems are used in German-speaking countries and internationally for the diagnostics of temporomandibular dysfunction (TMD). The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was developed and published in 1992 to enable standardized work in cross-disciplinary scientific research teams. This standard, which has in the meantime become internationally established in the field of TMD diagnostics, was subject to a thorough review in 2014 by an international team of scientists on the basis of a critical evaluation of the comprehensive study situation and the results of validation studies by an international team of scientists. Due to its simple and standardized examination techniques and validated diagnostic procedures, the resulting Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) is particularly well suited for use in daily practice. Using these criteria, the findings and diagnoses can be determined or formed according to scientific findings, and treatments can be performed in an evidence-based manner. The advantages and disadvantages of the DC/TMD are discussed in this article. In conclusion, this study protocol has all the prerequisites to form a unified standard of diagnostic findings country-wide in Germany. The great benefits of this include the valid and automatable generation of diagnoses and the inclusion of headache attributed to TMD. Keywords: diagnostic criteria, DC/TMD, clinical findings

For the treatment of temporomandibular dysfunctions (TMD) and bruxism, a novel therapy concept based on the application of individually manufactured ear inserts was presented. The aim of the present study was to examine the Cerezen system under routine conditions of dental practice and to evaluate it with regard to effectiveness, side effects, and particularities in its application. The evaluation showed that patients with TMD and bruxism can benefit from wearing the devices. Furthermore, a number of side effects and peculiarities have been identified that may be useful for the briefing of patients and/or the monitoring of future cases. The aim of the following investigation is to work out detailed indications for application. Keywords: clenching, grinding, ear inserts, awake bruxism, sleep bruxism, self-observation