3D-Video Based Protrusive Occlusal Registrations Are Accurate and Repeatable

Objectives: To investigate the accuracy and repeatability of a novel 3D-video technique for recording protrusive occlusal registrations.
Methods: A 3D-video recorder was constructed using a projector (Vivitek Qumi Q5, Vivitek Corporation, Hoofddorp, NL) and two cameras (uEye 1240LE, IDS Imaging, Obersulm, Germany). A ‘jailbar’ projection pattern enabled ‘contour lines’ of the scanned object to be recorded in a single exposure. The field of view was set to capture the upper and lower labial segment. Stone dental models were positioned in anterior protrusion. Two seconds of 3D-video was recorded of the labial segment. The models were moved continuously within an envelope of approximately 2mm (whilst maintaining their relative positions) to simulate a patient's involuntary head movements. Thirty labial protrusive occlusal registrations were recorded. The models were then positioned in left lateral excursion and two seconds of 3D-video was used to record thirty registrations. The ‘live’ patient was also recorded, using a scanning powder (CEREC Optispray, Sirona Dental Systems, Salzburg), to obtain twenty-nine occlusal registrations (<2s of 3D-video).
The stone models were digitized (ArKive Dental, Ripon, UK) to create dense ‘point clouds’. These models were aligned to all 89 occlusal registrations. Repeatability was assessed by comparing the variation in distance between three fixed reference points on the upper model, and three counterpart lower reference points (situated at two molars and an incisor). The accuracy of the ‘model’ scans was assessed by comparing the digital and actual contact points.

Results: The standard deviation of the variation in distance between corresponding upper and lower reference points was always <50µm. In all 267 cases, the range of variation was below +/-100µm. The digital contact points showed greater than 75% agreement with the observed contact points.

Conclusions: 3D-video enables rapid acquisition of multiple protrusive occlusal registrations, which are both accurate and repeatable.