01 September 2021

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Fabrication of provisional crowns: a randomized controlled trial comparing digital vs conventional workflow

Co-authors: A. Comba, F. Del Bianco

Lorenzo Breschi

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Digital technologies are evolving rapidly and, in particular, their use for the fabrication of temporary crowns is increasing. In fact following a digital workflow, an interim crown can be made by milling CAD-CAM blocks similarly to definitive crowns, through 3D printing process. However, to the author’s knowledge, no clinical study has compared the clinical efficiency of fabricating provisional crowns with a conventional workflow to that of crowns fabricated with a workflow. For these reasons Cheng et al. (2021) decided to compare the clinical outcomes of interim single crowns fabricated with the conventional workflow with those of crowns fabricated with the digital workflow. Fabrication time, fitting and the effect of the clinical experience of the operators were the factors evaluated by the authors of this paper.

 

Materials & Methods
The Chinese group of researchers enrolled forty participants in need of posterior tooth supported single crown and they were randomly allocated to either the digital or conventional group. In the digital group, the authors decided to fabricate the provisional single crowns by using digital sextant scans and computer-aided design and computer-aided manufacturing (CAD-CAM) technology without definitive casts. For the conventional group Cheng et al. (2021) 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 single crowns. The total fabrication time (laboratory and clinical) was recorded to evaluate time efficiency by the researchers. Fit assessment included marginal fit, proximal contact, occlusal contact, and crown morphology. Mann-Whitney U Test was used to analyze the data (a=.05).

 

Results
Cheng et al. (2021) revealed that the digital workflow required significantly less total fabrication time (laboratory and clinical) than the conventional workflow (P<.001). Furthermore, the researchers reported that the provisional single crowns fabricated with the digital workflow had significantly better fit and occlusal contacts than those fabricated with the conventional workflow (P=.005 and P<.001).

Conclusions
The authors concluded that the provisional single crowns fabricated with a digital workflow required shorter fabrication time and resulted in better fit than those fabricated with a conventional workflow, especially for less-experienced clinicians. (J Prosthet Dent 2021;125:73-81)

 

 

For additional information: 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.