Female Hormonal Fluctuation and Masticatory Function in Patients with Disc Displacement-A Case-Control Study

Purpose: The aim of this case-control study was to investigate the role female hormone fluctuation plays in maximum occlusal force and masticatory performance in female subjects presenting disc displacement with reduction (DDR) and matched controls. Materials and Methods: Sixty-five subjects were initially recruited; however, 4 of them were excluded during the study. The final sample included 14 subjects with DDR taking oral contraceptives, 16 control subjects without DDR taking oral contraceptives, 14 normally cycling subjects with DDR, and 17 normally cycling subjects without DDR. DDR was diagnosed by means of the Research Diagnostic Criteria for Temporomandibular Disorders axis I, and subjects without pain were selected. Maximum occlusal force was measured bilaterally in the molar region using a force transducer, and masticatory performance was analyzed using the artificial material comminution and sieving method. Variables were evaluated in four phases of three menstrual cycles, identified by ovulation testing. Data were submitted to the Mauchly sphericity test and PROC MIXED procedure of the SAS statistical program for repeated measures. Multiple comparisons were made using the Tukey-Kramer test (P = .05). Results: Comparisons among menstrual cycle phases showed no differences in occlusal force (P = .44) or masticatory performance (P = .09) for all volunteers. Subjects without DDR showed greater occlusal force (P = .01). No difference in occlusal force was found between subjects regardless of whether they took contraceptives (P = .15). Similarly, masticatory performance values did not differ among subjects with or without DDR (P = .09) or among those taking or not taking contraceptives (P = .29). Conclusion: Hormonal fluctuation did not influence mastication.