The effects of masseter muscle pain on biting performance

Abstract

The present study applied a standardized test food of known hardness to evaluate the biting performance of 20 female patients who had pain mainly in the masseter muscle during palpation. Another 20 women of a similar age group who were pain-free during examination served as controls. Electromyograms (EMG) of the masseter and sternocleidomastoid (SCM) muscles and the jaw position were recorded and measured when the subjects were biting through two types of test foods with known hardness (hard type, 20 kg hardness and extra-hard type, 60 kg hardness). Pressure-pain-threshold (PPT) values of both the patients and the normal subjects were obtained with an algometer. It was found that the PPT of the patients with pain was significantly lower and that the extra-hard food took more masseter muscle activity and more working side jaw movement in both the pain and the normal groups. During both hard and extra-hard food biting, a significantly longer duration of masseter muscle activity was found in pain patients while the total muscle activity was not significantly stronger. Strong correlation existed between SCM and masseter muscle activity during both hard and extra-hard food biting in the patient group, while such correlation was very weak in the normal group. In conclusion, painful masseter muscles required longer masseter and SCM muscle contraction time for breaking through a hard food of 20 kg and more, and co-activation of SCM and masseter muscles existed and was more evident when the food was harder or the pain was more severe.

Malocclusion, Mastication and the Gastrointestinal System

“…As do patients with morphological anomalies (including craniofacial developmental disorders [5,15]), persons with dysfunctional and parafunctional disorders in conjunction with reduced chewing performance [29,64] also present prolonged muscle contractions [75] and masticatory cycles [71], as well as altered masseter muscle activity [71,95]. Effects on gastrointestinal morphology and function have only been reported occasionally [19,20,81], not studied systematically.…”

“…Ebenso wie Patienten mit morphologischen Anomalien einschließlich kraniofazialer Entwicklungsstörungen [5,15] zeigen Personen mit dysfunktionellen und parafunktionellen Störungen neben einer Verringerung ihrer Kauleistung [29,64] auch verlängerte Muskelkontraktionen [75] und Kauzyklen [71] sowie eine veränderte Masseteraktivität [71,95]. Auswirkungen auf die gastrointestinale Morphologie und Funktion wurden bislang nur episodisch berichtet [19,20,81], jedoch nicht systematisch untersucht.…”

Bite force measurement in children with primary dentition

“…Determination of individual bite force levels has been widely used in dentistry in order to understand muscle activity and mandibular movements during mastication 1 and masticatory performance 2 , to study the influence of physiological factors on changes in occlusal forces 3,4 , and for investigations on the biomechanics of prosthetic devices. Very few contemporary studies appear to have been undertaken that focus on young children with primary dentitions and those available tend to focus on small sample groups and include a significant number of participants who have either temporomandibular disorders or malocclusion 5,6 .…”

Masticatory myofascial pain, and tension-type and chronic daily headache

“…Indeed activity in muscle nociceptors tends to induce inhibition of the alpha motoneuron pool during contraction (Lund and Stohler 1994). Furthermore, patients with MMP demonstrate shorter endurance at submaximal contractions (Clark et al 1984;Gay et al 1994) and a substantially reduced biting force compared to controls, which has been attributed to muscle pain and tenderness (Buchner et al 1992;Shiau et al 2003). In summary, these findings are likely to reflect a protective mechanism that avoids further tissue damage, and do not lend support to the hypothesis of increased muscle activity in MMP patients.…”