Lack of associations between occlusal and cephalometric measures, side imbalance in striatal D2 receptor binding, and sleep-related oromotor activities

Aims: First, to evaluate possible orofacial morphologic differences between sleep bruxers and non-bruxers, and second, to determine possible correlati ons between morphologic factors and striatal D2 receptor expression in pers ons with sleep-related oromotor activities. Methods: Twenty subjects were i ncluded in this study; half of them had polysomnographically confirmed orom otor values above the cutoff points for sleep bruxism. For all participants , 26 standard occlusal measures were recorded clinically and from dental st udy casts. In addition, 25 standard angular and linear measures were taken from standardized cephalometric films, and variables were derived to evalua te dental and skeletal relationships. Fourteen of the 20 participants had a lso participated in a previous study that included iodine-123-iodobenzamide (I-123-IBZM) and single-photon emission-computed tomography (SPECT). For t hem, the sine-to-side difference in striatal D2 receptor binding was determ ined as the neurochemical outcome measure. Results: Following the classical Bonferroni adjustment for multiple testing, no morphologic differences wer e found between the sleep bruxers and the non-bruxers. In addition, none of the morphologic variables were significantly associated with the neuroimag ing data. Conclusion: Taking into account the low power of this retrospecti ve, exploratory study, the results suggest that the orofacial morphology of sleep bruxers does not differ from that of non-bruxers. In addition, morph ologic factors are probably not involved in the asymmetry in striatal D2 re ceptor distribution that was previously observed in association with sleep bruxism.