Evaluation of the marginal gap and the three-dimensional trueness of suprastructures generated from scanning two different substructure framework materials for full arch implant-supported restorations

This study aimed to assess and compare the influence of intraoral scanning of 2 different full-arch implant-supported frameworks on the marginal adaptation and the 3D trueness of the suprastructures generated from the scanned frameworks. Two milled maxillary implant-supported frameworks were used in this study. The frameworks were manufactured from 2 different materials, Group I: titanium and Group II: Poly-Ether-Ether-Ketone (PEEK). A desktop scanner (Medit MD-1D0410, Medit Corp) was used to scan each framework once creating a reference scan, then the frameworks are tightened inside the patient mouth and an intraoral scanner (Medit i700; Medit Corp) was used to scan each framework 10 more times. From each intraoral scan, suprastructures were designed and 3D printed. The horizontal marginal gap between the finish line of the framework and the suprastructure for each group by using a stereomicroscope (SZ1145TR; Olympus). Every suprastructure in each group was assembled on the framework, tightened to the model, and scanned (n = 10) by using a desktop scanner. The suprastructures were scanned and compared with the reference file to evaluate 3D trueness through color-difference mapping by using a software program (The Medit link compare tool, Medit Design v3.0.6, Build 286; Medit Corp). Regarding the marginal gap, the titanium group had a significantly lower average marginal gap (70.99 ± 6.53) µm than the PEEK group (101.87 ± 21.51) (P = 0.0001). Regarding the 3D trueness of the 3D printed suprastructures, the titanium framework showed significantly less RMS value deviation from the reference scan (124.30 ± 23.39) µm than the PEEK framework (212.60 ± 54.76) µm (P < 0.001). Intraoral scans of titanium frameworks produced suprastructures with superior marginal adaptation and 3D trueness compared to PEEK frameworks. However, the average marginal gap in both frameworks was considered clinically acceptable. This trial, number NCT06423482, is registered at Clinical.gov. Date of trial registration 21/05/2024”.