Fear of Pain Mediates the Association between MC1R Genotype and Dental Fear.

Fear of pain is experienced in acute and chronic pain populations, as well as in the general population, and it affects numerous aspects of the orofacial pain experience, including pain intensity, pain-related disability, and pain behavior (e.g., avoidance). A related but separate construct-dental fear-is also experienced in the general population, and it influences dental treatment-seeking behavior and oral and systemic health. Minimal work has addressed the role of genetics in the etiologies of fear of pain and dental fear. Limited available data suggest that variants of the melanocortin 1 receptor (MC1R) gene may predict greater levels of dental fear. The MC1R gene also may be etiologically important for fear of pain. This study aimed to replicate the finding that MC1R variant status predicts dental fear and to determine, for the first time, whether MC1R variant status predicts fear of pain. Participants were 817 Caucasian participants (62.5% female; mean ± SD age: 34.7 ± 8.7 y) taking part in a cross-sectional project that identified determinants of oral diseases at the community, family, and individual levels. Participants were genotyped for single-nucleotide polymorphisms on MC1R and completed self-report measures of fear of pain and dental fear. Presence of MC1R variant alleles predicted higher levels of dental fear and fear of pain. Importantly, fear of pain mediated the relation between MC1R variant status and dental fear (B = 1.60, 95% confidence interval: 0.281 to 3.056). MC1R variants may influence orofacial pain perception and, in turn, predispose individuals to develop fears about pain. Such fears influence the pain experience and associated pain behaviors, as well as fears about dental treatment. This study provides support for genetic contributions to the development/maintenance of fear of pain and dental fear, and it offers directions for future research to identify potential targets for intervention in the treatment of fear of pain and dental fear.