Oral appliances for managing sleep bruxism in adults: a systematic review from 2007 to 2017

The review focuses on the last decade of research regarding the use of various oral appliances (OAs) in the management of sleep bruxism (SB) in adults. Sixteen (n = 16) papers of 641 identified citations involving 398 participants were included in the review. Of them, seven were randomised controlled trials (RCTs), seven were uncontrolled before-after studies and two were crossover trials. Analysis of the included articles revealed a high variability of study designs and findings. Generally, the risk of bias was low-to-unclear for RCTs and high for crossover studies, whilst the before-after studies exhibited several structural limitations. Nine studies used polysomnography/polygraphy/electromyography for SB diagnosis, whilst others were based on history taking and clinical examination. Most of them featured small samples and were short term. Of the studies using objective SB evaluations, eight showed positive results for almost every type of OA in reducing SB activity, with a higher decrease for devices that are designed to provide a certain extent of mandibular advancement. Among the studies using a subjective SB evaluation, one demonstrated a significant reduction in SB activity, and additional two showed a myorelaxant effect of OA in SB patients. Although many positive studies support the efficiency of OA treatment for SB, accepted evidence is insufficient to support its role in the long-term reduction of SB activity. Further studies with larger samples and sufficient treatment periods are needed to obtain more acknowledgements for clinical application.