Mandibular elevator muscles: physiology, action, and effect of dental occlusion

Department of Oral Function and Physiology, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
European Journal Of Oral Sciences (Impact Factor: 1.73). 09/1993; 101(5):314 - 331. DOI: 10.1111/j.1600-0722.1993.tb01127.x

ABSTRACT In spite of differences in embryologic origin, central nervous organization, and muscle fiber distribution, the physiology and action of mandibular elevator muscles are comparable to those of skeletal muscles of the limbs, back, and shoulder. They also share the same age-, sex-, and activity-related variations of muscular strength. With respect to pathogenesis, the type of muscular performance associated with the development of fatigue, discomfort, and pain in mandibular elevators seems to be influenced by the dental occlusion. Clinical research comparing the extent of occlusal contact in patients and controls as well as epidemiologic studies have shown reduced occlusal support to be a risk factor in the development of craniomandibular disorders. In healthy subjects with full natural dentition, occlusal support in the intercuspal position generally amounts to 12–14 pairs of contacting teeth, with predominance of contact on first and second molars. The extent of occlusal contact clearly affects electric muscle activity, bite force, jaw movements, and masticatory efficiency. Neurophysiologic evidence of receptor activity and reflex interaction with the basic motor programs of craniomandibular muscles tends to indicate that the peripheral occlusal control of the elevator muscles is provided by feedback from periodontal pressoreceptors. With stable intercuspal support, especially from posterior teeth, elevator muscles are activated strongly during biting and chewing with a high degree of force and masticatory efficiency, and with relatively short contractions, allowing for pauses. These variables of muscle contraction seem, in general, to strengthen the muscles and prevent discomfort. Therefore, occlusal stability keeps the muscles fit, and enables the masticatory system to meet its functional demands.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated the influence of two different occlusal indicators (articulating papers of 40μm and 200μm) on muscular activity of the temporalis anterior (TA) and superficial masseter (MS) during maximum voluntary clenches (MVC), using surface electromyography (SEMG). It was hypothesized that an articulating paper positioned between dental arches during MVC elicits a different muscular activity compared with the occlusion on natural dentition (without the occlusal indicator). 30 healthy adult subjects with a complete, natural dentition were recruited; SEMG activity was recorded in the following experimental conditions: MVC with cotton rolls for standardization purposes; MVC on natural dentition; MVC onto the 40μm or 200μm paper indicator positioned on right or left side of the dental arch. Percentage Overlapping Coefficient (POC; separate values obtained for TA and MS), antero-posterior coefficient (APC) and total muscle activities (IMP) were the analyzed SEMG parameters. The use of an occlusal indicator statistically changed POC_TA, POC_MS and IMP median values (p<0.05). Both 40μm and 200μm occlusal papers did not significantly affect APC values (P=0.86). A pronounced asymmetric muscular activity has been recorded with the introduction of an interocclusal media. All indices of muscular activity did not differ between sexes (Kruskal Wallis test, P>0.05). In conclusion, the examined articulating papers affected two specific SEMG parameters (POC and IMP); the recorded muscular activity with the occlusal indicator varied regardless left or right side positioning, and independently from tested paper thicknesses. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Journal of Electromyography and Kinesiology 04/2015; DOI:10.1016/j.jelekin.2015.04.006 · 1.73 Impact Factor
  • Source
    08/2013; 2(2):77-85. DOI:10.17126/joralres.2013.017
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mastication and deglutition are rhythmic automatic behaviours driven by the segmental central pattern generators (CPG), but they are also strongly modulated by peripheral afferent feed-back. Both mastication and deglutition may also be cerebrally driven. Mastication may be modulated by the cerebellum. Functional occlusion, i.e. the relationships between morphological occlusion and mastication, need to be studied; occlusion influences mastication mainly via feed-back and possibly feed-forward regulation. The interrelationship between the manducatory apparatus and cervical spine is under study, e.g. jaw opening and closing are in phase, but with a delay, with cervical spine extension and flexion, respectively (this implies cervical feed-forward motor regulation).


Available from
May 23, 2014