Comparison of scanning protocols in distal end implant supported prostheses; An in vitro study

Abstract

Purpose: To compare the scanning accuracy of various scan strategies and buccal bite registration sides in distal end implant supported prostheses. Materials and methods: A 3D printed full arch dentition maxillary model and partial edentulous mandibular model replaced by dental implants with scanbodies on the left mandibular second molar, left mandibular first molar, and left mandibular second molar were prepared and subsequently mounted on an articulator. The models were then digitized using a laboratory scanner for the reference scan. Using an intraoral scanner for experimental scans. Various scan strategies were tested 10 scans per group in dataset 1, including quadrant scans starting from the scanbody (QS-S), quadrant scans starting from the natural tooth (QS-T), full arch scans starting from the scanbody (FS-S), and full arch scans starting from the natural tooth (FS-T), then saved as STL files. Dataset 2 studied different sites of buccal bite registration. The experiments were divided into 3 groups used identical maxillary and mandibular virtual models without the scanbody inserted: recording the area of interest, recording across the area of interest, and recording both sites. Each group were scanned 10 times. The accuracy of scanbody positions, comprising trueness and precision, in dataset 1 and the accuracy of Virtual Interocclusal Records (VIRs) in dataset 2 were assessed in reverse engineering software. These results were then subjected to one-way analysis of variance (α = 0.05) for statistical analysis. Results: The results regarding trueness and precision indicated no statistically significant difference in the Root Mean Square Errors (RMSEs) among all experimental groups (p<0.001). The FS-S pattern displayed both the lowest trueness (42.4±4.0 μm) and precision (16.8±2.8 μm). Furthermore, the accuracy of VIRs exhibited a significant difference among different sites (p < 0.001). The highest deviation was scanned across the area of interest (283.0±17.8 μm) Conclusions: Varying scan strategies and buccal bite registration sides impacted the scanning accuracy in distal end implants supported prostheses. Keywords: accuracy, scanbody, scan strategy, virtual interocclusal record