Translation and rotation movements of the mandible during mouth opening and closing

Abstract

To assess the relative contribution of rotation and translation of the temporomandibular condyle-disc assembly during opening and closing movements, free movements of maximum mouth opening and closing were recorded in healthy subjects (12 men, 14 women) using an optoelectronic three-dimensional motion analyzer. For each subject, the displacement of the lower interincisal point, the path of the condylar reference point, the degree of rotation around the three orthogonal rotational axes, and the relative contribution of translation and rotation were calculated during all movement of mouth opening and closing. The distance covered by the interincisor point and the rotational angle about the transverse axis at maximum mouth opening were larger in men than in women, but the difference cancelled after correcting for mandibular radius in the sagittal plane; mandibular rotation was always larger than translation, but never approaching 100%; opening and closing translations were similar within sex, but their paths were longer in men than in women (P < 0.05); rotational angles around vertical and sagittal axes were negligible; the linear correlation between maximum mandibular opening and condylar translation was minor and not significant. In normal subjects, mouth opening and closing as modeled at the interincisor point was determined more by mandibular rotation than by translation, but in no occasion a pure rotation was found. The percentage rotation was not identical during mouth opening and closing; female and male paths were not totally coincident; no correlation between maximum mandibular opening and condylar translation was found.

Electromyographic activity of the jaw muscles and mandibular kinematics in young adults with theoretically ideal dental occlusion: Reference values

“…Lewis et al (8) found no relationship between maximum opening and mandible size, while Gallagher et al (29) found no relationship with body height. However, Mapelli et al (30) found higher mandibular opening values in males than in females, a difference that disappeared when mandibular radius was applied as a correction factor. More specific studies are needed to confirm this hypothesis.…”

A New Method to Move Mandible to Intercuspal Position in Virtual Three-Dimensional Orthognathic Surgery by Integrating Primary Occlusion Model

“…Moreover, the condyle cannot move back to the glenoid fossa because no translational movement of the condyle is possible in this rotation process (Fig 1D) in contrast to the existence of actual condylar movement. 4 Thus, the rotated mandible was anterior to the mandible in the intercuspal position (Fig 1D), and the actual mandibular-cranial and mandibular-maxillary relationship in the anteroposterior and transverse direction cannot be achieved by this rotation. Therefore, other methods were necessary to move the mandible to the intercuspal position to obtain an actual mandibular-cranial and mandibularmaxillary relationship.…”

Three‐dimensional analysis of jaw kinematic alterations in patients with chronic TMD – disc displacement with reduction

“…The range of mandibular movements was assessed at maximum mandible descent (MMO), protrusion (MMP) and laterotrusions (MML), calculating the projections of the displacement of its landmarks (cranial–caudal, ventral–dorsal, medial–lateral) as well as its sagittal, coronal and horizontal angles (Fig. S1, Supporting information).…”

“…During mouth opening and closing, the peak‐to‐peak lateral deviation of IP was computed; also, the mean velocity of both IP and CRPs in the two phases was calculated in the temporal span between 5% and 90% of MMO. The sagittal mandibular movement during mouth opening and closing was further divided into its rotation and translation components ; in each frame of motion, the relative percentage contribution of the two components to the total movement was calculated for each condyle. To compare different subjects, the mandibular movement was normalised on MMO distance (sagittal projection): mouth opening and closing were sampled in 10% steps, and for each step, the corresponding percentage of translation component (CRP translation index) was calculated for both condyles.…”

“…In this study, we detailed the TMJ dynamic behaviour of DDR patients by means of an optoelectronic tracking system, focusing on the assessment of the relative contribution of jaw rotation (condyle‐disc compartment) and translation (mandibular fossa‐disc compartment) , because alterations in their reciprocal magnitude have been identified as important indicators of TMJ dysfunction .…”