Dental Students' Perceptions of Digital and Conventional Impression Techniques: A Randomized Controlled Trial

The aim of this randomized controlled trial was to analyze inexperienced dental students' perceptions of the difficulty and applicability of digital and conventional implant impressions and their preferences including performance. Fifty undergraduate dental students at a dental school in Switzerland were randomly divided into two groups (2×25). Group A first took digital impressions in a standardized phantom model and then conventional impressions, while the procedures were reversed for Group B. Participants were asked to complete a VAS questionnaire (0-100) on the level of difficulty and applicability (user/patient-friendliness) of both techniques. They were asked which technique they preferred and perceived to be more efficient. A quotient of "effective scan time per software-recorded time" (TRIOS) was calculated as an objective quality indicator for intraoral optical scanning (IOS). The majority of students perceived IOS as easier than the conventional technique. Most (72%) preferred the digital approach using IOS to take the implant impression to the conventional method (12%) or had no preference (12%). Although total work was similar for males and females, the TRIOS quotient indicated that male students tended to use their time more efficiently. In this study, dental students with no clinical experience were very capable of acquiring digital tools, indicating that digital impression techniques can be included early in the dental curriculum to help them catch up with ongoing development in computer-assisted technologies used in oral rehabilitation.

Clinical Fitting and Adjustment Time for Implant-Supported Crowns Comparing Digital and Conventional Workflows

PURPOSE

The aim of this prospective cohort study was to investigate clinical and laboratory performance of implant-supported reconstructions comparing the digital to the conventional workflow.

MATERIALS AND METHODS

Twenty study participants were treated in a cross-over design for single-tooth replacement in posterior sites, each with a customized titanium abutment plus computer-assisted design and computer-assisted manufacturing (CAD/CAM)-zirconia-suprastructure (test: digital workflow; n = 20) and a standardized titanium abutment plus PFM-crown (control: conventional pathway; n = 20). Evaluation of the 40 reconstructions included: 1) feasibility of laboratory cross-mounting of each abutment-crown-connection, and 2) assessment of adaptation time for clinical adjustments of interproximal and occlusal surfaces. Statistical analyses were performed using the exact Wilcoxon rank sum tests.

RESULTS

Laboratory cross-mounting was feasible for three reconstruction pairings revealing a 15% vice versa transfer success rate. All implant crowns could be provided successfully within two clinical appointments, independently of the workflow used. The mean clinical adjustment time was significantly lower (p < .001) for test reconstructions from the digital workflow with 2.2 min (standard deviation [SD] ± 2.1) compared with the ones from the conventional pathway with 6.0 min (SD ± 3.9).

CONCLUSIONS

The digital workflow was almost threefold more efficient than the established conventional pathway for fixed implant-supported crowns. Clinical fitting could be predictably achieved with no or minor adjustments within the digital process of intraoral scanning plus CAD/CAM technology.