Continuous Scan Strategy (CSS): A Novel Technique to Improve the Accuracy of Intraoral Digital Impressions

Abstract

Purpose: To present the results obtained with the "Continuous Scan Strategy" (CSS), a direct intraoral scanning technique based on the connection of the implant scan bodies (SBs) with thermoplastic resin.

Methods: 40 patients were restored with 45 long-span monolithic implant-supported zirconia restorations (10 partial prostheses [PP] and 35 full arches [FA]) fabricated via a full-digital workflow after the capture of an intraoral impression (Trios3®) using the CSS technique. The primary outcomes were the marginal adaptation and passive fit of the superstructures, checked at T0 (intraoral try-in of polyurethane or metal replica of the final prosthesis) and T1 (delivery of the final zirconia restoration). The secondary outcomes, registered at T2 (2 years after the delivery of the final prosthesis), were implant survival, prosthetic success, and complications. A throughout statistical analysis was performed.

Results: At T0, 40/45 replicas demonstrated a perfect passive fit and adaptation. At T1, one prosthesis had fractured, and at T2, an additional prosthesis had fractured and one had chipped. The implant survival rate was 100%. The prosthetic success was 93.3%.

Conclusions: CSS seems to represent a viable option for capturing accurate intraoral digital impressions for the fabrication of precise long-span implant-supported restorations.

Keywords: Accuracy; Fixed Implant Prosthodontics; Intraoral Digital Impressions; Intraoral Scanners; Passive Fit; Prosthetic Success.