Randomized clinical trial of a conventional and a digital workflow for the fabrication of interim crowns: An evaluation of treatment efficiency, fit, and the effect of clinician experience

Abstract

Statement of problem: Limited information is available regarding the fabrication of tooth-supported interim single crowns (SCs) with either a digital or a conventional workflow.

Purpose: The purpose of this randomized clinical trial was to compare the time efficiency and fit of interim crowns fabricated by using either a digital or a conventional workflow.

Material and methods: Forty participants in need of posterior tooth-supported SCs were enrolled and randomly allocated to either the digital or conventional group. In the digital group, the interim SCs were fabricated by using digital sextant scans and computer-aided design and computer-aided manufacturing (CAD-CAM) technology without definitive casts. The conventional group included conventional impressions and direct fabrication of the interim restorations intraorally. Five experienced and 5 less experienced clinicians were randomly assigned to fabricate the interim SCs. The total fabrication time (laboratory and clinical) was recorded for time efficiency. The fit assessment included marginal fit, proximal contact, occlusal contact, and crown morphology. The evaluated parameters were analyzed with the Mann-Whitney U Test (α=.05).

Results: The digital workflow required significantly less total fabrication time (laboratory and clinical) than the conventional workflow (P<.001). The less-experienced clinicians needed longer clinical time with the conventional workflow than the experienced ones (P=.023). In contrast, the laboratory time and total fabrication time were shorter for less-experienced clinicians using the digital workflow (P=.005 and P=.015). The interim SCs fabricated with the digital workflow had significantly better fit and occlusal contacts than those fabricated with the conventional workflow (P=.005 and P<.001). With the digital workflow, the interim SCs made by less-experienced clinicians were of the same quality as those made by experienced clinicians. When using the conventional workflow, the fit of the experienced clinicians was significantly better than that of the less-experienced clinicians.

Conclusions: The interim SCs fabricated with a digital workflow required a shorter fabrication time and resulted in better fit than those fabricated with a conventional workflow, especially for less-experienced clinicians.