Work carried out within the FOP/Unicamp research line included collaboration with Unochapecó and Unifesp
Professor Maria Beatriz Duarte Gavião, from the Faculty of Dentistry of Piracicaba (FOP) at Unicamp, has maintained a line of research for 12 years that investigates bruxism, a repeated activity of the masticatory muscles that can occur during sleep [sleep bruxism, considered as a movement disorder] or when the individual is awake [awake bruxism]. Both types are characterized by grinding and/or clenching of teeth. Recently, a study was carried out that used the polysomnography technique to diagnose sleep bruxism in adults, resulting from the collaboration between the Postgraduate Program in Dentistry at FOP-Unicamp and the Community University of the Chapecó Region (Unochapecó), in addition to of Unifesp's participation. The work brought data that expands the understanding of the disorder, considered difficult to manage by dentistry, as polysomnography is the technique that provides the definitive diagnosis of the problem.
The study was developed in the context of the interinstitutional doctorate at FOP-Unicamp and Unochapecó, defended by João Vicente Rosar, professor at the Santa Catarina institution. He was supervised by professor Paula Midori Castelo, from Unifesp, who is accredited with the FOP Postgraduate Program in Dentistry. According to Professor Beatriz, who was Paula's postdoctoral supervisor, one of the focuses of her line of research is focused on evaluating sleep bruxism in children and adolescents. “Professor Paula was the one who introduced the topic of sleep bruxism in adults to the group. She used more modern and effective methods, which allowed for a more accurate diagnosis of the disorder,” she explains.
Also according to Professor Beatriz, sleep bruxism in children and adolescents is usually diagnosed through parental reports. “In the case of the work carried out by João Vicente, with guidance from Professor Paula, the polysomnography technique was used, which contributes to the diagnosis of various disorders associated with sleep, including sleep bruxism”, she explains. During polysomnography, the patient sleeps with electrodes attached to the body, which allows the simultaneous recording of electrophysiological variables, such as brain electrical activity, eye movement, muscle activity, heart rate, respiratory flow and effort, blood oxygenation, snoring and body position.
All experimental work, according to Professor Paula, was carried out by João Vicente in Chapecó. He used for analysis a group of 43 adults aged between 20 and 40, of both sexes, university students. “The group was divided into two segments: one with 28 individuals diagnosed with sleep bruxism, called GBS, and the other with 15 healthy volunteers, called the control group (CG)”, details the Unifesp professor.
The GBS group received an interocclusal device (occlusal splint) and was evaluated before, one month and two months after starting therapy. During this period, João Vicente collected data related to maximum bite force, sleep quality, salivary cortisol levels and signs of temporomandibular disorder (TMD) symptoms. The CG group was also evaluated at three moments, but did not receive any type of therapy. “Patients who used the plate reported, through responses to a questionnaire, an improvement in sleep quality and a reduction in headaches and pain in the jaw area. It is difficult to assess, however, whether the device really improved sleep quality or whether it merely exerted a placebo effect”, ponders Professor Paula.
In any case, the analyzes of the data collected showed significant differences during the evaluations carried out with the GBS group regarding the increase in the strength of the masticatory muscles, improvement in functional and muscular indices and in the quality of sleep. Salivary cortisol concentration and joint index did not show significant changes throughout the trial. As for the CG group, there was no significant difference in the variables considered at the three assessment moments. “The results suggest that the use of the interocclusal device for two months has a positive effect on maximum bite force, range of mandibular movements, muscular symptoms and quality of sleep in patients with bruxism associated with TMD”, points out Professor Paula.
She warns, however, that the use of the plate is not recommended for everyone with sleep bruxism and that the device does not prevent the onset of the disorder, which has a central origin. “It is necessary to have a lot of criteria to indicate the use of the interocclusal device. Patients need to be evaluated carefully. Symptoms must be identified precisely. The study demonstrated an important effect provided by the plaque, but this does not mean that this resource can be used without distinction”, says the Unifesp professor.
Treating sleep bruxism, notes Professor Beatriz, is not a trivial task. According to her, it is important to know what type of problem the disorder causes in the oral cavity and in the structures of the masticatory system. Only after a comprehensive assessment can a decision be made on which therapy to adopt. Furthermore, comorbidities may be associated and must be precisely diagnosed, as they can be determinants of sleep bruxism, such as upper air tract disorders, gastroesophageal reflux or even the routine use of centrally acting medications.
However, the professor adds, the idiopathic cause should not be ruled out. “In the case of children, there is often no clinical manifestation of pain. If they still have deciduous teeth [baby teeth], we often do not adopt any procedure. In the mixed or permanent dentition phase, if the child experiences muscle pain and fatigue, or even tooth wear, the use of splint may be recommended. But it is important to emphasize that this device will not solve the problem of sleep bruxism, which has a central origin”, he details.
A valid recommendation for both children and adults, highlights Professor Paula, is to take care of what experts classify as sleep hygiene. This means sleeping in a dark environment, without noise and without the presence of equipment such as a television, cell phone or tablet. Most of the studies developed within the line of research on bruxism are financed with resources from the São Paulo Research Support Foundation (Fapesp), Coordination for the Improvement of Higher Education Personnel (Capes) and the National Council for Scientific and Technological Development (CNPq).
