The influence of altered occlusal guidance on condylar displacement

Abstract

This study investigated mandibular displacement and masticatory muscle activity during clenching in lateral occlusal position in relation to the lateral occlusal pattern. Twenty healthy human subjects (mean = 26.5 years) volunteered for this study. Metallic occlusal overlays were fabricated for the lower working side canine to second molar and non-working side second molar in order to simulate a canine protected occlusion, group function occlusion and bilateral balanced occlusion (balancing contact). Three-dimensional displacements of the bilateral condyle and electromyography (EMG) activities in the bilateral masseter, anterior and posterior temporalis were recorded during maximal clenching. The experimental occlusal pattern was revealed to have statistically significant effects on both condylar displacement and EMG activity (P < 0.001 and P < 0.001, respectively). When compared to the simulated group function occlusion, the simulated canine protected occlusion and balancing contact caused statistically significant smaller superior displacements of the non-working side condyle, which suggests that they may result in reduced temporomandibular joint (TMJ) loading. Furthermore, the simulated canine protected occlusion was associated with the lowest EMG activity, which suggests that this occlusal pattern has the capacity to reduce the level of parafunctional activity.

A dynamic model of jaw and hyoid biomechanics during chewing

“…On jaw-closing, the incisor region typically laterodeviates about 5 mm, then moves medially as the food bolus engaged (Ahlgren, 1976;Gibbs and Lundeen, 1982;Miller, 1991). The mandibular condyles' lateral translation is minimal (0.4-0.6 mm) during chewing and other tasks (Gibbs and Lundeen, 1982;Payne, 1997;Okano et al, 2002;Otake et al, 2002;Miyawaki et al, 2004;Huang et al, 2006). During bolus compression therefore, the jaw rotates around its ipsilateral condyle as the contralateral condyle returns to its articular fossa (Gibbs and Lundeen, 1982;Gallo et al, 2000Gallo et al, , 2006Palla et al, 2003;Gallo, 2005;Miyawaki et al, 2001).…”

A three-dimensional computerized tomography study into the morphological interrelationship between anterior and posterior guidance and the occlusal scheme in human Caucasian skulls

“…It is also widely accepted that one of the main tasks of occlusion is to ensure function with minimum muscular activity [12][13][14][15] thereby protecting the masticatory organ from dysfunction and ultimately from damage. Both cusp inclines and condylar path inclination seem to have a profound influence on the forces acting within the joints and the dentition [16,17].…”

Established prosthodontic rules confirmed in natural adolescent occlusion

“…It has been reported that occlusions with anterior canine guidance allow less muscular activity and forces within the stomatognathic system during parafunction than occlusions with group function patterns and balanced occlusions [10][11][12][13][14][15][16][17][18][19]. For long-term success and stability it has been suggested that an occlusal concept be established which keeps the muscular activity of the patient at the lowest level and thereby prevents the stomatognathic system from dysfunction or possibly self-destruction [20,21].…”