The Integration of Occlusal Transfer Plates into a Digital Workflow
Maria F. Alfaro, Michael E. Razzoog
Digital impressions are in constant improvement and offer several advantages over conventional impressions. However, their utilization is still dependent on given clinical scenarios - case/patient specific (Khraishi e Duane, 2017).
•For cases involving multiple preparations or full arch rehabilitation, the use of conventional impressions, and model digitization with desktop optical scanners is still considered a recommended workflow. The questionable cross-arch stitching accuracy and the limited methods to digitize mandibular movements during the intraoral capturing methods have been previously described (Wesemann et al., 2017).
•A virtual face-bow has been proposed as a method to transfer maxillary teeth by intraoral scanning to a 3D extra-oral image using facial scanning involving a final transfer to a virtual articulator. (Solaberrieta, Garmendia, et al., 2015; Solaberrieta, Minguez, et al., 2015; Lam et al., 2016) Nevertheless, the use of this virtual method is not very straightforward and requires the use of cumbersome and expensive instruments (Park et al., 2017).
•A method to transfer transfer casts from a mechanical articulator to a virtual articulator still requires the need to mount stone models first before transferring them into a virtual articulator (Park et al., 2017).
•Desktop optical scanners are considered a great instrument to digitize stone models (Wesemann et al., 2017). Studies have shown that the dimensional accuracy (11 ±3 μm) of stone casts has been found to be higher than that of CAD/CAM-generated dental casts (27 ±7 μm) (Langenwalter et al., 1990; Cho et al., 2015). Based on these results the effect of the dimensional distortion from stone models in regards of occlusal contact reproduction is considered to be minimal (Krahenbuhl et al., 2016).
•A coordinated system with cast-reference to a mechanical articulator utilizing multiple digital platforms has been proposed. This virtual-analog process was considered unnecessarily complicated by clinicians and laboratory technicians (Solaberrieta et al., 2013).
•Generally, the design of digital prostheses has been based on maximum intercuspation (static) occlusion from either digital or conventional interocclusal records. The lack of occlusal dynamicity increases laboratory and chairside adjustments to eliminate occlusal interferences (Park et al., 2017).
1. New digital technology available allows the clinician and the dental laboratory to work together in a virtual environment, improving the overall diagnosis and treatment outcomes.
2. With the aid of the articulator transfer calibration object and the occlusal transfer plates, additional occlusal information can be virtualized and integrated into the design software.
3. The use of this transferring technique saves one step (occlusal or bite scan) for every single scanned case.
4. A CAD platform that can reproduce dynamic occlusion as in the physical articulator will provide desired information utilized during the design steps. This information will diminish the need for further manual adjustments.