Stereometric Assessment of TMJ Space Variation by Occlusal Splints

Abstract

Occlusal splints are used for the management of temporomandibular disorders, although their mechanism of action remains controversial. This study investigated whether insertion of an occlusal splint leads to condyle-fossa distance changes, and to mandibular rotation and/or translation. By combining magnetic resonance images with jaw tracking (dynamic stereometry), we analyzed the intra-articular distances of 20 human temporomandibular joints (TMJs) before and after insertion of occlusal splints of 3 mm thickness in the first molar region. For habitual closure, protrusion, and laterotrusion in the contralateral joint, occlusal splints led to minor--yet statistically significant--increases of global TMJ space and to larger increases at defined condylar areas. Condylar end rotation and translation in habitual closure were reduced. Hence, the insertion of a 3-mm-thick occlusal splint led to a change in the topographical condyle-fossa relationship, and therefore to a new distribution of contact areas between joint surfaces.

The dental occlusion as a suspected cause for TMDs: epidemiological and etiological considerations

“…While both types of intervention differ with regard to their reversibility, they have two features in common: (i) Both approaches alter the three‐dimensional intermaxillary relationship. (ii) By doing so, they change the recruitment patterns within the masticatory muscles (76, 77) as well as the position of the mandibular condyles within the TMJs (78). As a consequence, stress concentrations in defined muscle regions are altered and localised painful areas are less loaded (79), thus reducing the severity and/or incidence of pain.…”

Influence of balancing‐side occlusal interference on smoothness of working‐side condylar movement and intra‐articular space in chewing efforts

“…It has been shown that asymptomatic children and adolescent with disc displacement and corresponding changes in intra‐articular space are a majority rather than a minority , and patients with joint clicking are not rare even in children . Numbers of reports showed large variation in joint space for asymptomatic patients in association with varied type of occlusions. These findings suggest generation of redistributing contact areas between joint surfaces responding to the varied occlusions.…”

“…More importantly, dynamic stereometry (7) has permitted the assessment of contact and compression areas between the joint articular surfaces. The method revealed that the insertion of occlusal splint led to sig-nificant increase in condyle-fossa distances, both during habitual closure and sliding movements (8). In addition, joint clicking led to changes in trajectory of minimum condyle-fossa distances during movement and intercuspation (9).…”

Current computational modelling trends in craniomandibular biomechanics and their clinical implications

“…Essentially an animation of virtual anatomy with subject‐specific movements, the approach has a high degree of validity when movements and spatial relationships are topics of interest. Consequently, it has been used to predict changes in parameters like muscle length, the helical axis of jaw rotation and articular spaces between the mandibular condyles and their fossae (41–44).…”