Influence of substructure material on the scanning accuracy and scannability of implant-supported full arch bar substructures

Bar substructures may be utilized for fixed full-arch implant-supported restorations, where suprastructures are cemented as prosthetic shells. Certain clinical situations may necessitate intraoral scanning of the bar substructures. However, the scannability and the accuracy of the intraoral scans remain unclear. This study aimed to compare and assess the scannability and the scan accuracy of two different bar materials used for implant-supported prostheses. Two maxillary implant-supported substructures (bars) were milled from 2 different materials. Group I from titanium and Group II from poly-ether-ether-ketone (PEEK). The substructures were digitized by using a desktop scanner (Medit MD-1D0410, Medit Corp). The STL file produced was considered the reference. Each substructure was scanned intraorally (n = 10) by using an intraoral scanner (IOS) (Medit i700; Medit Corp). The non-captured surface area in a preset time limit of 15 s (scannability) was assessed in (mm²). To evaluate the scanning accuracy, all STL files were imported into a surface-matching software program (Medit Design v3.0.6 Build 286; Medit Corp), where overall RMS (root mean square) deviations in (µm) were calculated. The Shapiro-Wilk test of normality was used. A comparison between the study groups was done by using an independent samples t-test. Significance was set at P < .05. The titanium substructure demonstrated better trueness and precision concerning deviation analysis (202.40 ± 27.57 and 197.50 ± 24.69, respectively) than the PEEK substructure (262.20 ± 30.87 and 244.1 ± 9.18, respectively) (P < .001). Regarding scannability, significantly more surface area was captured when scanning the PEEK substructure (985.42 ± 7.22) than titanium (951.15 ± 12.16) (P < .001). PEEK was more scannable. The titanium bar demonstrated significantly higher accuracy than the PEEK bar, which was more scannable than the titanium bar.This trial, number NCT06423482, is registered at Clinical.gov. Its start date was May 14, 2024.