The Amount of TMJ Displacement Correlates with Brain Activity

Abstract

The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the correlation between the severity of malocclusion and brain activation. The fMRI was used to measure blood-oxygenation- level-dependent (BOLD) signals of twelve healthy human subjects while they clenched in two different ways to simulate two types of malocclusion. In each malocclusion model, a custom-made splint forced the mandible to each of two retrusive positions (0.5 mm, 0.7 mm). A no-modification splint provided the control. We compared the BOLD signals measured at each clenching position with those measured during the corresponding resting conditions. The BOLD signals were significantly stronger in the amygdala and the prefrontal area (PFA) when subjects clenched in the two retrusive positions compared during clenching in the control position. In addition, the BOLD signal in the PFA increased as the simulated malocclusion became more severe. These results indicate that we may be able to objectively assess the severity of malocclusion via focus on the brain activity.

Comprehensive dental diagnosis and treatment planning for occlusal rehabilitation: a perspective

“…Any deviation and/or deflection of 0.6-0.8 mm in any direction (cranially, dorsally, or transversally) produces a loading situation for the components of the joints (bilaminar zone, articular disc, ligaments, and bony structures). [11][12][13][14][15] This leads to a neuromuscular avoidance reaction, i.e. compensation within the masticatory system 16 and the buffer regions of the neighboring organ systems (head position, shoulder girdle, vertebral spine, etc.).…”

“…[46][47][48][49] At the same time, occlusal contacts seem to be responsible for maintaining the condylar position within a physiological range. [12][13][14][15][16] Knowing that occlusal sensitivity is within the range of 0.02-0.03 mm, 48,[50][51][52][53][54][55] that TMJ has a 'deflection' tolerance of only 0.6-0.8 mm, [12][13][14][15]49 and that the angular difference between the steepness of the articular eminence and the contra-lateral canine guidance of any skeletal class is ≤10°, [53][54][55] it becomes clear that dentistry is dealing with a highly individual and highly complex organ system. 3,[56][57][58]…”

Study on regional activities in the human brain caused by low‐level clenching and tooth separation: Investigation with functional magnetic resonance imaging

“…Gum chewing is reported to activate the sensorimotor area, and clenching activates both the sensorimotor and supplementary motor areas in the human brain . Malocclusion is related to the stress response through brain function . The posterior deviation of the mandible may activate the limbic cortex and cause somatic symptoms .…”

“…Malocclusion is related to the stress response through brain function . The posterior deviation of the mandible may activate the limbic cortex and cause somatic symptoms . The use of an occlusal splint causes changes in occlusion and oral sensation, and consequently, the areas activated in the human brain will change.…”

Objective evaluation of taste stimuli with near-infrared spectroscopy measurements of prefrontal cortex activity

“…These neuroimaging techniques have also been used in dentistry to study how various oral conditions affect the brain [1][2][3][4]. However, the results of these studies have yet to be clinically translated, as the techniques are often expensive and difficult to apply.…”