Journal of Craniomandibular Function, 02/2021

Joint complaints are among the most common ailments worldwide, hindering people in performing their everyday activities and diminishing their quality of life. Many publications on pathologic changes and joint dysfunctions, including the temporomandibular joint (TMJ), focus on alterations in bone and cartilage. These publications mostly do not include the consideration of the synovial structural components. However, many pathologic changes as well as the initiation of repair processes of damaged joints occur in this region. This article describes the morphology of the joint cavity (fibrous membrane, synovial membrane) as well as the composition and properties of the synovial fluid (articular synovia) in healthy and diseased human TMJs. Keywords: synovial membrane, synovial fluid, temporomandibular joint, morphology, joint lubrication

Aim: The traditional hinge axis theory of temporomandibular joint (TMJ) dynamics is increasingly being replaced by the theory of instantaneous centers of rotation (ICR). Typically, ICR determinations are based on theoretical calculations or three-dimensional approximations of finite element models. Materials and methods: With the advent of real-time magnetic resonance imaging (MRI), natural physiologic movements of the TMJ may be visualized with 15 frames per second. The present study employs real-time MRI to analyze the TMJ biomechanics of healthy volunteers during mandibular movements, with a special emphasis on horizontal condylar inclination (HCI) and ICR pathways. The Wilcoxon rank sum test was used to comparatively analyze ICR pathways of mandibular opening and closure. Results: Mean HCI was 34.8 degrees (± 11.3 degrees) and mean mandibular rotation was 26.6 degrees (± 7.2 degrees). Within a mandibular motion of 10 to 30 degrees, the resulting x- and y-translation during opening and closure of the mandible differed significantly (10 to 20 degrees, x: P = 0.02 and y: P < 0.01; 20 to 30 degrees, x: P < 0.001 and y: P = 0.01). Rotation of both 0 to 10 degrees and > 30 degrees showed no significant differences in x- and y-translation. Near occlusion movements differed only for y-translation (P < 0.01). Conclusion: Real-time MRI facilitates the direct recording of TMJ structures during physiologic mandibular movements. The present findings support the theory of ICR. Statistics confirmed that opening and closure of the mandible follow different ICR pathways, which might be due to muscular activity discrepancies during different movement directions. ICR pathways were similar within maximum interincisal distance (MID) and near occlusion (NO), which might be explained by limited extensibility of tissue fibers (MID) and tooth contact (NO), respectively.(Original article published in Int J Comput Dent 2020;23:
235–244.) Keywords: temporomandibular joint, jaw dynamics, biomechanics, real-time magnetic resonance imaging, instantaneous center of rotation

In the first 11 years (2009–2019) of the Journal of Craniomandibular Function (CMF), 44 issues and one Festschrift have been published. In the present systematic quantitative analysis, all articles published during this period were assigned to the categories “Science,” “Practice,” “Journal article,” “Congress and continuing education report” or “Book review,” and were evaluated according to topic frequency. The total volume is 3,765 pages, distributed in 344 articles and 45 editorials, with the participation of 321 authors from 18 countries. The most frequent topic is occlusion, followed by pain, diagnostic procedures, determination of jaw relation, and bruxism. More than twice as many articles were published from the scientific community than from dental practice (ratio 2:1). Diagnostic (as compared to therapeutic) articles dominated the scientific articles (ratio 2.6:1). Forty-five editorials, 46 congress reports, 43 journal articles, and 45 book reviews round out the overall picture. Keywords: journal, journal article, author, bruxism, occlusion, temporomandibular disorders

Craniomandibular dysfunction (CMD) is a disease associated with pain in the masticatory system and is amenable to treatment. In specialist practices and clinics, however, CMD often appears with other pain symptoms and clinical syndromes other than those of the jaw, frequently resulting in a diffuse and seemingly elusive overall picture. In some specialist articles, CMD is described as a consequence of chronic body pain or fibromyalgia syndrome. Similarly, there is a school of thought that considers comorbidities outside of the craniomandibular region to be a predisposing factor for the development of CMD. Despite the controversial discussion about the possible connections between functional diseases of the craniomandibular system and the other body regions, this case report describes – against the background of the present authors’ clinical experience – how with the co-therapy of symptoms both inside and outside the craniomandibular system, even therapy resistant, whole-body complaints can often be successfully treated. The electromyographic examination as part of the interdisciplinary treatment of CMD and its comorbidities and the valuable collaboration with manual therapists will likewise be demonstrated. Keywords: comorbidities in craniomandibular dysfunction (CMD) and craniocervical dysfunction (CCD), fibromyalgia syndrome (FMS), Widespread Pain Index (WPI), myocentric occlusal splint therapy, electromyography (EMG), transcutaneous electrical neurostimulation (TENS), Arlen’s atlas therapy, manual therapy