PRACTICAL APPROACHES FOR THE ACCURACY OPTIMIZATION OF DENTAL IMPLANTS’ POSITION REGISTRATION DURING INTRAORAL SCANNING PROCEDURE: CLINICAL OBSERVATIONS REGARDING USAGE

Abstract

Currently available approaches used for the optimization of registration accuracy of dental implants’ position during intraoral scanning involve the use of additional tools and instruments, use of three-dimensional printing technology, and transition to the new scanning methods that may require the purchase of additional hardware or software, which complicates the possibility of their widespread implementation in clinical dental practice with a reasonable level of cost-effectiveness. Given this, it remains relevant to search for and develop methods that are focused on improving the strategies and approaches of intraoral scanning itself using available tools and taking into account the principles of constructing and reconstructing images obtained using an intraoral scanner.Objective. To analyze existing approaches for the accuracy optimization of dental implants’ position registration during the intraoral scanning procedure and assess frequency of using such based on actual clinical observations, while also to evaluate the possibilities and feasibility of their practical implementation.Methods. Clinical part of the study involved the analysis of 58 cases of intraoral scanning during the total rehabilitations of dental patients with dentures supported by dental implants, which were carried out within the clinical bases of the Faculty of Dentistry of the State Higher Educational Institution «Uzhgorod National University». During the analysis of the scanning cases, the applied scanning strategies and modifications of such based on the clinical experience of doctors were taken into account, which could potentially contribute to accuracy optimization of dental implants’ position registration on edentulous jaws in the structure of the obtained digital impressions. Analytical part of the study involved retrospective review of literature devoted to the study of variations in the levels of trueness and precision of intraoral scans during the modifications of approaches used for intraoral scanning in order to optimize the accuracy of registering the position of dental implants on edentulous jaws.Results. Analysis of 58 cases of intraoral scanning obtained during the total rehabilitation of dental patients with prosthetic constructions supported by dental implants revealed following features of the scanning process, which contributed to the accuracy optimization of dental implants’ position registration: in 86,20% of cases changes to the scanning strategies originally proposed by the manufacturer of the intraoral scanner were applied; in 48,27% of cases implementation of the scanning process immediately with fixed scan abutments (without obtaining a preliminary scan from the edentulous jaw before fixing the scan abutments) was provided; in 65,51% of cases light polymerization liquid resins were used for the purpose of conditional splinting or as separate fiducial marker; in 13,79% of cases independent specialized fiducial markers with an adhesive attachment system to the mucosa were used; in 24б13% of cases approach with blocking of a stably scanned fragment before detailed scanning of each individual scan-abutment within the software was applied.Conclusions. The results of the observations held among practical cases of intraoral scanning during the total rehabilitation of dental patients with prosthetic constructions supported by dental implants have shown that most often, in order to improve the quality and accuracy of the scan, dentists in their clinical practice used the options of changing scanning strategies originally proposed by the manufacturer of the intraoral scanner, ensuring the maximum possible dryness of the working field using the relief of the immobile mucosa for the continuity of the scanning process, as well as using, in order to ensure the continuous scanning process, light-curing materials based on liquid resins, which either performed the function of non-specific independent fiducial markers, or were used to connect individual scan abutments, simulating the implementation of the continuous/ongoing scanning strategy. Most often, modifications of scanning strategies were represented by the implementation of zigzag movements and those that provided a circumferential/circular pattern around the scan abutments.