Feasibility, trueness and precision of intraoral scanners in digitizing maxillectomy defects with exposed zygomatic implants in situ: An in vitro 3D comparative study

Objectives

To in-vitro evaluate the feasibility and accuracy (trueness and precision) of various intraoral scanners (IOS) to digitize maxillectomy defect models with exposed zygomatic implants in situ.

Material and Methods

Six partially edentulous and edentulous maxillectomy defect models with 2 zygomatic implants each were obtained. References scans were obatined by using a laboratory scanner (inEos X5; Dentsply Sirona). Three IOS, Trios 3, Trios 4 (3Shape A/S), and Primescan (Dentsply Sirona) were used first to digitize the entire model including implants and then to only scan the exposed part of zygomatic implants. The feasibility was assessed by evaluating the intraoral scanner's ability to accurately capture the maxillectomy defects and zygomatic implants, compared to a reference standard. Trueness and precision were evaluated using software's global best-fit alignment (GOM Inspect, GOM GmbH). Multifactorial analysis of variance (ANOVA) was used to compare the mean 3D deviation according to different scanners, groups, and model types. The significance level used in the analyses was 5 % (α=0.05).

Results

All scanners showed adequate feasibility to scan the entire maxillectomy defects and exposed implants regardless of the structural complexity. The results of trueness showed that Primescan has the smallest 3D deviations (0.0252 mm) followed by Trios 4 (0,0275 mm), and then Trios 3 (0.0318 mm) (p < 0.001). The results of precision showed that Primescan had the smallest 3D deviations (0.0026 mm) followed by Trios 3 (0,0080 mm), and then Trios 4 (0,0097 mm) (p < 0.001).

Conclusion

Intraoral scanners differ in feasibility, trueness and accuracy of all scans, with Primescan providing the best combination of feasibility, trueness and accuracy, followed by Trios 4 and Trios 3.

Clinical Significance

Scanning maxillectomy defects with various exposed zygomatic implants can be feasible and accurate using intraoral scanners (Trios 3, Trios 4, and Primescan). The use of intraoral scanners for implant-prosthetic rehabilitation of maxillectomy defect can be a feasible alternative that can improve and simplify the workflow.