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.

Acute ergogenic effects of wearing occlusal splints have been reported for aerobic and anaerobic exercises, but the literature centered on performance improvement by using jaw repositioning splints is scarce. We aimed to analyze the effect of wearing a 50% lower jaw advancement splint on biophysical and perceptual responses at low to severe running intensities. Sixteen middle- and long-distance runners performed twice a 7 × 800 m intermittent running protocol (with 1 km·h⁻¹ increments and 30 s rest periods) in an outdoor track field using two lower intraoral splints (a placebo and a lower jaw advancer). These devices were custom manufactured for each participant and a randomized and repeated measure design was used to compare conditions. No differences between placebo and lower jaw advancer were found (e.g., 52.1 ± 9.9 vs. 53.9 ± 10.7 mL·kg⁻¹·min⁻¹ of oxygen uptake, 3.30 ± 0.44 vs. 3.29 ± 0.43 m of stride length and 16 ± 3 vs. 16 ± 2 Borg scores), but small effects were sometimes observed (e.g., 109.2 ± 22.5 vs. 112.7 ± 25.2 L·min⁻¹ of ventilation, ES = −0.42). Therefore, this jaw advancement splint had no substantial ergogenic effect on biophysical and perceptual responses when running at different intensities.

Oral health involves physiological functions related to mouth, teeth and orofacial structures, but also includes psychological and social dimensions. In this sense, oral health is an integrated part of human general health and well-being. Our aim was to access and evaluate the general oral health status of a high- and elite-level sample of Portuguese athletes from different sports. One hundred and sixteen participants were examined regarding their dental relationships, teeth and periodontal health, the presence of parafunctional activities (bruxism), and current or past orthodontic treatment. Our sample were predominantly adolescents and young adults, including 54 high-level and 62 elite subjects (71 males and 45 males) from 11 different sports, but mainly from swimming and athletics. Most sport performers presented with normocclusion (77%), despite the presence of other sagittal, transverse and vertical malocclusions. Twenty-three participants were affected by dental caries and six had missing teeth. Gingivitis (~40%) and dental calculus (~30%) were presented in our sample. Bruxism signs (47%) and current or past orthodontic treatment (~22%) were also found. Oral health conditions are not under control among high- and elite-level athletes, supporting the importance of healthcare needs and oral health promotion strategies in sports.