Changes in pulp sensitivity across the menstrual cycle in healthy women and women with temporomandibular disorders

Background Menstrual cycle may contribute to experimental pain measures in healthy women and women with chronic pain. Objectives The present study aimed to investigate variation in pulp sensitivity across the menstrual cycle in healthy women and women with temporomandibular disorders (TMD) and to explore the effect of TMD pain and psychosocial variables on the pulp response. Methods This longitudinal study involved 47 regularly menstruating women aged 20-45, 24 healthy and 23 with diagnosed painful TMD. The electric and cold stimuli were performed by electric pulp tester and refrigerant spray, respectively, on mandibular lateral incisors, in five menstrual phases (menstrual, follicular, periovulatory, luteal and premenstrual). Research Diagnostic Criteria for TMD were used to assess TMD, chronic pain, depression and somatisation. Regression analysis was performed to investigate the effect of the predictor variables on the pulp sensitivity. Results Significant phase-related differences were observed for pain intensity to cold stimuli. Higher pain sensitivity was reported in menstrual in comparison with luteal phase (P = .019) among healthy women, and in menstrual in comparison with follicular (P = .033), periovulatory (P = .003) and luteal (P = .007) phases in TMD women. No significant differences were recorded for electric stimuli. Regression analysis identified depression as the determinant of cold and electric response in menstrual phase, regardless of age and presence of TMD. Conclusion Menstrual phase in healthy and TMD women with regular menstrual cycle is characterised with higher pulp sensitivity to cold stimuli. Depressive symptoms independently influence pulp response in this phase.