Functional characteristics of the temporomandibular joint following registration of centric relation using various anterior deprogrammers

BACKGROUND: The management of temporomandibular joint musculoskeletal disorders is no longer confined to theory but is advancing to a new level with the introduction and adoption of modern diagnostic techniques. The integration of occlusal relationships with the physiological movements of the mandible has now become feasible, generating interest among dental practitioners and gnathologists worldwide.

AIM: To conduct a comparative assessment of various types of deprogrammers used for recording the centric relation and to evaluate the dynamic changes in the functional parameters of the temporomandibular joint.

METHODS: An interventional (experimental) multicenter prospective selective controlled non-blinded randomized study was performed. To assess the functional parameters of the temporomandibular joint in patients with increased wear of hard dental tissues of grades II–III severity, functional tests of the temporomandibular joint and axiography (in the Arcus Digma II system, KaVo) were performed. One hundred individuals were included, ranked into groups of 20 patients. The assessment was carried out at the diagnostic stage, after the procedure of registering the centric relation and 3 months after orthopedic treatment. During the registration of the centric relation, deprogramming devices (Lucia jig, Koise deprogrammer, leaf gauge, Lucia jig combined with elements of M. Rocabado's cranio-postural kinesiotherapy) were used in each group. The Friedman statistical test was used to assess the dynamics of changes in quantitative indicators in related populations.

RESULTS: The study results after registration of the centric relation with preliminary deprogramming of the masticatory and temporal muscles indicate an improvement in the parameters and their approximation to the norm. In the Lucia jig group, changes in the Bennett angle (angle of the transverse condylar path), ISS (angle of immediate side shift), and the Gothic arch angle were observed: the obtained values corresponded to the norm in 98% of cases. In the Koise deprogrammer group, 90% of patients showed correct parameters of mandibular movement. Preservation or minor changes in the parameters were observed in 10% of the patients. In the leaf gauge group, 75% of the participants showed correct parameters of mandibular movement. The remaining 25% of patients demonstrated preservation of the numerical values of mandibular movement after the registration of the centric relation using the deprogrammer. The results in the group combining the Lucia jig and elements of M. Rocabado’s gymnastics corresponded to normal values in 100% of cases. The obtained dynamic indicators point to the presence of a positive effect of kinesiotherapy for patients with manifestations of temporomandibular joint dysfunction.

CONCLUSION: All the methods for registering the centric relation used in this study are applicable in clinical practice to eliminate the “accidental” selection of the mandibular position and, consequently, incorrect prosthetic rehabilitation. It is necessary to consider the specifics of each clinical situation and to choose a deprogramming appliance according to the severity of the temporomandibular joint pathology, patient comfort, and the planned prosthetic procedures.