Electromyographic amplitude variability of chewing cycles in deaf individuals.

This study had the goal of determining if the amplitude of the surface electromyograph signals changes in terms of time of analysis and subjects, deaf or normal listeners, when estimated in a 250 ms of length window, visually determined, considering the most stable signal period from the center of the chewing cycle. In order to do this, groups with control subjects, listeners and deaf individuals, who made use of the Brazilian sign language (LIBRAS), were studied. All participants performed continuous 5 s of chewing for the electromyographic recording of the temporalis and masseter muscles. The normalized RMS values of three chewing cycles were compared between and among groups. The results from the Kruskall-Wallis test did not show any statistically significant differences (p > 0.05) between the normalized RMS values obtained in the three individual chewing cycles, for each of the two completed and evaluated cycles, in both groups studied. The Mann-Whitney test showed that the mean normalized RMS values obtained in the first chewing cycle were higher for the control group when compared to the mean amplitude values of the first chewing cycle of the group of deaf volunteers. It can be concluded that, in these experimental conditions, the RMS values obtained from the select windows of 250 ms length duration, in relatively stable periods of the electromyographic signal of chewing cycles did not suffer any changes in terms of EMG register duration, in both studied groups, but does give evidence of the differences among the groups.

Sliding plates on complete dentures as a treatment of temporomandibular disorder: a case report.

This work presents a case report of a woman, aged 62, who presented with signs and symptoms of temporomandibular disorder (TMD). The patient reported pain in the masticatory system and examination showed a reduction in the occlusal vertical dimension (OVD). She was treated with complete dentures incorporating a modification to the posterior regions developed by the authors and which were termed "sliding plates." Through analysis of photographs taken of the patient prior to the extraction of the patient's natural dentition, sliding plates were utilized to reestablish the OVD. The sliding plates also allowed for unrestricted eccentric mandibular movements, thereby accelerating the neuromuscular deprogramming and making it possible for the mandible to adopt a more physiologic position. The dentures reduced the pain and were well-accepted by the patient. Therefore, sliding plates may be of great benefit to completely edentulous patients with painful symptoms that result from alterations in the OVD and inappropriate condylar positioning.