Journal of Craniomandibular Function, 01/2009

The masticatory muscles are characterized by specific functional, histochemical, and micro-morphological properties, which distinguish them essentially from other striated muscles of the trunk and the extremities. Especially, the endowment of the muscle fibers with a redundant variety of myosin-isoform combinations gives this musculature an almost unlimited repertoire of contraction behavior. Along with the so-called heterogeneous activation capability, which allows the generation of discrete force vectors within the individual muscle, these properties provide the basis for sophisticated fine motor control of the masticatory muscles. Furthermore, the differential internal structuring is evidence for scientific hypotheses, which might explain not only the biomechanics of muscle micro-lesions, but also the therapeutic effectiveness of oral splints. Keywords: masticatory muscles, differential activation, muscle pain, temporomandibular disorders, oral splints

The following questions are addressed: To what extent are patients with a temporomandibular disorder (TMD) and controls affected by neck and back pain? Do differences exist between patients and controls? Do differences exist between TMD subgroups characterized by myofascial pain, joint pathology, or a combination of these? One hundred and thirty-four TMD patients and 38 asymptomatic controls were evaluated. Patients with muscle-related and combined disorders were found to be significantly more often affected by neck and back pain than were controls. Patients with only joint-related disorders did not significantly differ from controls. The muscle-related and combined groups also gave significantly higher values for TMD-associated pain intensity than the joint-related group. Multivariate logistical regression analysis showed that the presence of myofascial pain of the mastication muscles was the most powerful predictive parameter for the occurrence of neck and back pain. The presence of joint disorders together with myofascial pain still gave significantly elevated factors compared to controls. Joint disorders without myofascial pain proved not to be significantly associated with elevated prevalence of neck and back pain. With regard to neck and back pain in TMD patients, significant differences exist between TMD subgroups characterized by joint pathology and/or myofascial pain. This might be related to different states of the nociception processing neurological systems resulting in different levels and distribution patterns of widespread musculoskeletal pain. Keywords: orofacial pain, musculoskeletal pain, temporomandibular disorder, neck pain, back pain, widespread pain

Background: MRI is the gold standard in the diagnosis of internal derangement (ID). The aim of the study was to reexamine patients with MRI-verified disc displacement (DD) without reduction after conservative therapy by splints clinically and by MRI to control morphologic changes. Patients: Twenty-eight patients with DD without reduction underwent clinical and MRI examination at the beginning of conservative treatment and again a mean of 23.3 months later. The morphology of disc, condyle, fossa articularis, position of the condyle within the fossa and translation of the condyle were described in parasagittal T1-weighted images, and the presence of hyperintense signals in T2-weighted MRIs. Results: Clinical parameters such as muscle palpation, extent of mouth opening, and pain intensity improved significantly after therapy. The condyle showed significant degenerative changes, the translation of the condyle improved, and hyperintense signals disappeared. Changements of the disc, position of the condyle, and degree of internal derangement were not significantly different in a comparison of both MRIs. Conclusion: By conservative treatment, structural changes in joints with DD without reduction could not be prevented, but the clinical symptoms improved significantly nevertheless. Keywords: disc displacement without reduction, MRI, CMD, internal derangement

Modern functional diagnosis is carried out in a series of steps appropriate to the indications. If a craniomandibular dysfunction or disorder (CMD) is strongly suspected, clinical functional analysis is the first step of the diagnostic cascade. The fundamental elements of this examination have been established for decades. Since the 1990s, new standards have been established requiring an extended clinical exam in which psychosomatic and orthopedic influences are also sought. Computer-based systems are available to evaluate the results and to help correlate the clinical findings with the appropriate diagnoses (CMDfact). The same data can be utilized in new patient information systems and evidence-based expert systems for treatment planning. They can be used in systems for semi-automatic compilation of patient records for referring physicians ("Arztbrief-Assistent CMD"; medical report assistant CMD). The findings from medical imaging have to be checked against the clinical functional analysis. Computer-based systems for this particular application are near completion and clinical use (CMDtomo), while systems for the processing of instrumental findings are being developed (CMD3D). The importance of clinical functional analysis is likely to increase as software-based diagnostic instruments facilitate practitioners' assessments of findings, and this will put them in a similar position to specialist centers where they could consult with colleagues. Keywords: clinical functional analysis, craniomandibular dysfunction, craniomandibular disorder, CMD screening, computer-based documentation, diagnostic software