Evaluation of minimum interdental threshold ability in dentate female temporomandibular disorder patients

Minimum interdental threshold is the smallest thickness that can be detected between teeth during an occlusion and has an influence on the occlusal force and on the control of mandibular movements. The aim of this study was to assess the possible association of the signs and symptoms of temporomandibular disorders (TMD) with the ability to detect a minimum interdental threshold. Two hundred women were equally divided into four groups: asymptomatic (control), subjects with masticatory muscle pain, with articular [temporomandibular joint (TMJ)] pain and mixed (muscular and articular pain). Evaluation of the ability to detect a minimum interdental threshold was performed using aluminium foils with 0.010, 0.024, 0.030, 0.050, 0.080 and 0.094 mm of thickness in the premolar region. A total of 20 tests with each thickness for each patient were performed, starting with the thickest foil (0.094 mm) and ending with the thinnest one. The myogenic pain and articular groups presented significantly higher threshold values (0.020 and 0.022 mm, respectively), when compared to the control. Both groups reached the level of certain perceptiveness only at 0.030 mm. No significant correlation was found between minimum interdental threshold and age. These results suggest that discrimination of thicknesses can be disturbed as a consequence of TMD manifestations and not the cause of it. Clinicians should, therefore, be aware that changes on muscles and TMJ can secondarily lead to occlusion changes. The mechanisms involved in this process, however, are not well understood and warrant further investigation.