Haskell BS, Voor MJ, Roberts AM., et al. - In patients with obstructive sleep apnea (OSA), researchers conducted this scoping review to describe the efficacy of oral appliances (OAs) by considering morphologic interaction. They searched databases (Medline, PubMed, The Cochrane Library, EBSCO) using terms OA treatment effectiveness a nd positive and/or negative outcome predictors. They included craniofacial predictors of OAs and OSA biomechanical factors of anatomical traits associated with OA efficacy. Analysis of 140 articles in the searched literature showed alterations in musculature and pharyngeal airway structure through OA use, and these alterations were individually unpredictable with wide variability. Experts need to develop an integrated basis for identifying morphological and biomechanical elements of phenotypic expressions of sleep disordered breathing in the design and application of OAs. Current information is heterogeneous and has high variability. They need to recognize subgroups of OSA patients responding to OAs.