Reproducibility of condyle position and influence of splint therapy on different registration techniques in asymptomatic volunteers.

The current study aims to analyze and quantify the effects of different registration techniques on the reproducibility of condyle position and the influence of stabilization splint therapy on the technique's reproducibility. Three-dimensional electronic-condylar-position analysis (EPA) with an ultrasound-based jaw-tracking system was recorded during intermaxillary registration of manually guided centric relation (CR), maximal intercuspation (MI), and clenching-force-dependent Gothic arch tracing guided centric relation (DIR method) before (T0) and after (T1) splint therapy. Patients were supplied with a stabilization splint for three months on the basis of the DIR registration. Participants were 26 asymptomatic volunteers with a mean age of 30.6 +/- 9.5 years. The registration technique was found to have a significant (p = 0.001) effect on condylar displacement in all axes before, and in X- and Y-axes after splint therapy. Condyles during DIR were found to be in a more anterior-inferior position compared with CR and MI, with the condyles in the latter position being likewise more anterior than in CR. There were significant (p < 0.03) differences in reproducibility of the condyle position dependent on the technique, both at T0 and T1. The DIR method showed the highest reproducibility, followed by MI and CR. There was no significant effect of time of investigation on the technique's reproducibility.