Ultra-low frequency transcutaneous electric nerve stimulation does not affect the centric relation registration

OBJECTIVE: To evaluate the influence of ULF-TENS on the displacement of the mandibular condyle and on the repeatability of centric relation (CR) registration of three different techniques: bimanual manipulation (BM), long strip technique, and harmonic centric occlusal relationship (R.O.C.A. wires). METHODS: Twenty-five participants without temporomandibular disorder (TMD) underwent two study stages conducted via electronic position analysis: (1) three CR records were made, one for each manipulation technique; (2) the ULF-TENS was applied for 30 min, and after that the same CR records were repeated. STATISTICAL ANALYSES: Mann-Whitney, ICC, and one-tailed F test. RESULTS: The ULF-TENS did not influence the condyle total displacement, regardless of CR recording technique used (p > 0.05). BM showed an improvement in repeatability after ULF-TENS. DISCUSSION: Concerning the variance, BM showed less variation at the X-axis. Long strip technique and R.O.C.A. wires varied less at the Y-axis. Long strip technique was again less variable at the Z-axis.