Military pilots are characterized by peculiar job conditions related to intense accelerative stresses. For this, they frequently report work-related neck and back pain and are affected by bruxism. The aim of this case-control study is to analyze the occlusion time (OT) in a sample of military pilots affected by bruxism, compared with healthy non-pilot subjects. 14 military pilots, all males (mean age 35.14 ± 2.32 y), affected by bruxism, were compared with an age matched control group of 14 male subjects (mean age 32.29 ± 4.84 y). The T-Scan computerized occlusal analysis system (Tek-Scan Inc., Boston, MA, USA) was used to record the subjects’ occlusion times during 4 mandibular opening-closing movements. Military pilots affected by bruxism showed a statistically significant lower (reduced of 85%) mean OT, compared with control subjects (p < 0.0001). Military pilots are characterized by a highly reduced occlusion time compared to healthy non-pilot subjects. This feature could not be only related with the presence of bruxism but with their particular clinical job-related condition that causes different dental and stomatognathic system problems. Further studies are encouraged to enhance the scientific knowledge in this field.

The purpose of this study is to analyse the neuromuscular balance of the masticatory muscles and the influence on the athlete respiratory parameters induced by custom-made mouthguard. Twenty-six athletes (24 males and 2 females), of different disciplines, average age of 32.12 ± 12.05, were recruited. Each athlete received a custom-made mouthguard in the Ethylene-Vinyl-Acetate (EVA) thermoplastic material and using surface electromyography, the masseter muscles and the frontal beams of the temporal muscles were analysed, with and without mouthguard. The athletes were then subjected to a medical examination and cardiopulmonary test, in the condition with and without mouthguard. The use of mouthguard caused an improvement of all the electromyographic indexes analysed. In particular, GLOBAL INDEX (p = 0.0021), BAR (p = 0.0005), IMPACT (p = 0.0076) and ASIM (p = 0.0290) showed an enhancement statistically significant. For the cardiopulmonary test indexes as maximum oxygen uptake (VO 2 max), minute ventilation (VE), breathing reserve (BR), not statistically differences (p > 0.05) were reported. The custom-made mouthguard improved the neuromuscular balance of the masticatory muscles, symmetrizing the masseters and temporalis muscles work. It produced a better balancing distribution of occlusal loads both in the anterior-posterior direction and in the lateral direction and offered the possibility to produce more muscular work. Moreover, it did not constitute an impediment that can significantly disturb the athlete's breathing during physical activity.

This paper aims to numerically investigate the protective efficiency of multilayered and boil-and-bite mouthguards on orofacial hard and soft tissues subjected to impact loadings. To the best of our knowledge, this is the first attempt which studies the protective efficacy of mouthguards on orofacial injuries including both hard and soft tissues such as articular disks, stylomandibular and sphenomandibular ligaments, that are commonly neglected in clinical and numerical studies. To address this issue, a finite element based numerical framework has been proposed using the Abaqus finite element software. This study considers three different situations of the craniofacial structure, without any mouthguard, with the customized multilayered mouthguard and with a boil-and-bite mouthguard. The protective effectiveness of mouthguards is numerically evaluated based on pressure and displacement distributions on the orofacial hard and soft tissues under two different actual impact loadings. In all cases the results revealed that the customized multilayered mouthguard can more effectively reduce the stress concentration on orofacial hard and soft tissues which is the key factor to evaluate the protective efficiency of different types of mouthguard. As an example, a comparison between the protective efficiency of multilayered and boil-and-bite mouthguards reveals that under uppercut punch impact loading, the multilayered mouthguard performs 18.45% and 21.32% more effective respectively for upper and lower teeth and stylomandibular ligament. Furthermore, the simulation results for stylomandibular ligament and articular disk enable us to conclude that wearing a customized multilayered mouthguard cannot be replaced by a boil-and-bite mouthguard, since it causes more harm in comparison to the unprotected case.