Effect of an exclusion range of jaw movement data from the intercuspal positionon the estimation of the kinematic axis point

In patients who have lost natural occlusal contacts, the centric relation is usually estimated based on several anatomical factors such as the temporomandibular joint and masticatory muscles except dental arch. The clinical procedure to record the centric relation often depends on the clinicianʹs expertise and technique; an objective method to determine proper occlusal position is desirable. The kinematic axis point (KAP) is kinematically estimated from sagittal movements and is an ideal posterior reference point that is used in dental articulators for reproducing jaw movement. Occlusal registration using the KAP may serve as a definite objective technique. The aim of this study is to investigate the effect of the exclusion range of sagittal jaw movement data from the intercuspal position (ICP) on the estimation of the KAP. The complete and incomplete sagittal border movement data of dentate subjects were used to estimate the KAPs. The locations of the estimated KAPs were compared. The results indicate that the incomplete sagittal border jaw movement data set does not include data points inside a 7 mm distance from the ICP can be used for estimation of the KAP. In conclusion, the sagittal border jaw movement data around the ICP is not indispensable in the valid identification of the KAP.