Phenotypes of Painful TMD in Discordant Monozygotic Twins According to a Cognitive-Behavioral-Emotional Model: A Case-Control Study

Abstract

Abstract Objectives this case-control study’s objective was to investigate variables based on a cognitive-behavioral-emotional model related to the development of painful temporomandibular disorders (TMD) in a sample of monozygotic twins discordant for the condition. Materials and Methods 20 monozygotic twins (10 pairs discordant for painful TMD), aged between 18 and 55 years, were studied. The diagnosis of painful TMD was determined according to the Diagnostic Criteria for Temporomandibular Disorders - Brazilian Portuguese (DC/TMD). The cognitive-behavioral-emotional variables analyzed were sociodemographic profile, pain sensitivity (pain threshold to pressure, allodynia, and hyperalgesia), oral behaviors, pain vigilance and awareness, pain catastrophizing, central sensitization, stress, anxiety, depression, alexithymia, mindfulness facets, sleep quality, pain control, pain intensity and interference, trigeminal and extratrigeminal pain areas. Results According to the adjusted regression model, there was an increased chance of TMD with: an increasing left-sided masseter face pain sensitivity score (OR = 3.29;95%CI=(0.17–62.8),p = 0.428); an increasing total pain catastrophizing score (OR = 1.08; 95%CI=(0.64–1.8),p = 0.776); an increasing score of difficulty in externalizing feelings (OR = 1.61;95%CI=(0.13–2.9),p = 0.539); and a scoring of the distraction facet of the FFMQ scale (OR = 4.65;95%CI=(0.39–55.7),p = 0.225). Conclusions from the cognitive-behavioral-emotional model studied in this case-control study of monozygotic twins discordant for painful TMD, painful sensitivity in the face, catastrophizing pain, difficulty in externalizing feelings, and the distraction facet (mindfulness) are variables that increase the chance of developing painful TMD. Clinical Relevance: This study with discordant monozygotic twins allows phenotype analyses, minimizing genetic and social influences. The results elucidate that cognitive-behavioral-emotional variables increase the chance of developing painful TMD, despite genetic influences.