The study assessed the differences in electromyographic (EMG) activity recorded during clenching in women with chronic unilateral temporomandibular disorders (TMDs) as compared to control subjects. Seventy-five full dentate, normo-occlusion, right-handed, similarly aged female subjects were recruited. Twenty five subjects presented with right side TMD, 25 presented with left side TMD and 25 pain-free control subjects participated. Using integrated surface EMG over a 1 s contraction, the anterior temporalis and masseter muscles were evaluated bilaterally while subjects performed maximum voluntary clenching. Lower EMG activation was observed in patients with TMD as compared to control subjects (temporalis: 195.74+/-18.57 vs. 275.74+/-22.11, P=0.011; masseters: 151.09+/-17.37 vs. 283.29+/-31.87, P<0.001). An asymmetry index (SAI) was calculated to determine ratios of right to left sided activation. Patients with right-sided TMD demonstrated preferential use of their left-sided muscles (SAI -5.35+/-4.02) whereas patients with left-sided TMD demonstrated preferential use of their right-sided muscles (SAI 6.95+/-2.82), (P=0.016). This unilateral reduction in temporalis and masseter activity could be considered as a specific protective functional adaptation of the neuromuscular system due to nociceptive input. The asymmetry index (SAI) may be a useful measure in discriminating patients with right vs. left-sided TMD.

During clenching, a uniform distribution of the dental contact along the maxillar arches prevents the TMJ from overloading. In contrast, severe partial edentation seems to induce overloading of the TMJ with severity depending on the type of contact.

Introduction:Training on impression disinfection is often limited to brief explanations in the clinic. This investigation assessed knowledge on this topic amongst clinical students in our university, produced a pill of knowledge to suit their needs, and evaluated its impact and acceptance. Material and Methods:A pre-post study was designed to identify knowledge gaps using an anonymous, voluntary self-applied questionnaire before and after watching an audio-visual clip (pill of knowledge). All 136 students in the school were invited to enter the study (estimated sample size: 116).Results: Participants: 109 (26.6% in 3rd year; 37.6% in 4th year and 39.4% in 5th year).Participation dropped 10.29% (n = 95) in the post-intervention survey. Knowledge improvement was higher for those impression materials included in the pill. Most students (68.4%) reported to know more about impression disinfection after the pill and 70.5% felt more able to achieve correct disinfection. The pill was particularly well received (86.3%). All students would recommend it to their peers, and 93.5% are willing to receive pills on other topics. Discussion:Our results disclosed an important gap in knowledge, which can be filled by a single, brief and concise pill adapted to the intended audience. Once made readily available through digital repositories, it may help solve this problem, given the ubiquitous presence of mobile devices. Conclusions:Our results found pills of knowledge as a useful approach to facilitating undergraduates' learning process. This method, using suitable information and communication technologies, has the potential to improve the performance on certain clinical tasks.

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