Novel Approaches to Functional Occlusal Surfaces through Computer-Aided Design

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The purpose of this present study was to provide a virtual articulator, and to design a functional occlusal surface via a virtual articulator in VR space, with added insight provided by a haptic device.Our CAD/CAM system procedures composed of the 4 following steps : Step 1 : A virtual dentition model (VDM) was reconstructed through laser surface scanning data of dental casts, scanned with a 3D scanner via 3D mesh modeling software. Step2 : Scanned VDMs have an independent coordinate value. The relative position between upper and lower VDMs was decided via labial-buccal surface data from upper and lower casts placed at the intercuspal position. Step3 : The Virtual Reality crown (VR crown) was designed via Freeform and Phantom Omni. VDM data from functional occlusal surface was removed from crown data, and occlusal contact points were set and masked. The occlusal surface was shaped without modifying the occlusal contact. Abatement teeth data was removed from crown data. Step4 : The dental crown wax pattern was modeled from VR crown data via 3D printer. Occlusal contacts were assessed at the whole dentition, with/without CAD/CAM crown via an articulator, using silicone. The vertical gap between the finish line on the abutment teeth and the margin on the dental crown was 28±5μm in the conventional crown, 35±13μm in the CAD/CAM crown. The real crown's occlusal contacts almost corresponded with its VR crown. Conclusion : We developed a novel CAD/CAM system which can design functional occlusal surfaces via a modified FGP technique. The marginal fit in our CAD/CAM crown was sufficient for clinical application.