Zum unmittelbaren Einfluss aktiver Unterkieferbewegungen und manueller Untersuchungstechniken auf den einseitigen, chronischen Tinnitus

The exact connection between the temporomandibular joint (TMJ) and ear- symptoms such as tinnitus has not yet been fully investigated despite numerous clinical studies and several observations. The aim of this study was to investigate, if manual TMJ manipulations of 24 pa- tients have influence on the intensity or quality of their unilateral, chronic tinni- tus. Therefore the condyles were actively and passively put into their boundary positions and the “manual tinnitus-test” according to Schünemann (MTT) was implemented also to prove the hypothesis of a direction-dependent impact. Tin- nitus intensity was recorded at any position of the mandible by means of the numerical analogue scale (NAS), using 0.5 increments. In addition the cranio- mandibular system (CMS) of the subjects was examined for dysfunctions. In contrast to previous studies not only the influence of ear noises through jaw- movement or the occurrence of temporomandibular dysfuctions among tinnitus patients was investigated, but both and their correlations were examined statistically. A large proportion of the examined subjects recorded a short-term change in their one-sided, chronic tinnitus due to different jaw (border-) movements and provocation techniques. The MTT was the most effective of all manipulations and was able to immediately improve tinnitus intensity about 39% on average. Also the ipsilateral distraction (21%) and the bimanual manipulation, as most notable by Dawson (14%), showed clear decrease of the tinnitus intensity. Max- imum teeth clenching brought a mean increasement of 7%, with the laterotru- sion under opposing force a rise of intensity of 16.5% was observed. In two subjects tinnitus could not be influenced by active or passive jaw-movements nor by MTT. The most frequent TMD symptoms in our study population included tongue im- pressions (87.5%), dorsal arthralgia of the ipsilateral TMJ (75%), myalgia of the masseter (71%) and temporalis muscle (50%) as well as lateral arthralgia (62.5%), headache (46%) and anterior disc displacements in the TMJ (42%). If a rotating distraction of the mandible (MTT part 1) stretches the masseter and temporalis muscles to the extent that the sphenomandibular ligament and anterior ligament of the malleus can be tightened, motion of the auditory ossicles across jaw movements is possible (MTT part 2). The two mentioned ligaments form the tympanomandibular ligament, a relict of the embryological mandible. If it is possible to manipulate the position of the auditory ossicles, the oval window could be moved over the stapedial bone and peri- and endolmph shifts could be induced. These displacements might lead to a temporary release of a perma- nent contact between the tectorial membrane and inner hair cells, which is re- sponsible for the perception of sounds without an actual external sound source (tinnitus). According to osteopathic concepts this effect should be strengthened by an uprighting of the temporal bone (MTT part 2), since in this way the cere- bellar tentorium is used to manipulate the endolymph in the endolymphatic sac. Considering that the MTT provides the most effective and reliable way to imme- diately improve the subjective volume of a tinnitus over the jaw, tinnitus could temporarily be reduced or canceled by the described mechanism. Further stud- ies will have to examine whether the MTT can be used as a diagnostic tool to evaluate the treatment prospects of dental functional therapies in tinnitus. As already shown in previous studies our study results suggest a functional re- lationship between the temporomandibular joint and tinnitus. Therfore we sup- port the widespread hypothesis that tinnitus can be improved immediately and maybe even in a sustained manner through a functional rehabilitation of the stomatognatic system. The discussed biomechanical model for tinnitus devel- opment is understood as an additional notion of the etiology of a somatic tinni- tus. Further investigations are necessary to concretize the connections and to derive if possible long-acting therapeutic approaches, also with regard to other ear symptoms such as vertigo, hearing-impairement and sudden hearing-loss. Neuronal, neuromuscular, ligamentous, muscular and osseous structures need to be examined for their context.