Accuracy of complete arch implant scans recorded by using intraoral and extraoral photogrammetry systems

Statement of problem

Extraoral photogrammetry (PG) systems provide a reliable method for recording implant positions; however, the accuracy of an intraoral PG system integrated into an intraoral scanner (IOS) system remains unknown.

Purpose

The purpose of this in vitro study was to compare the accuracy of complete arch implant scans captured by using 4 extraoral and 1 intraoral PG system.

Material and methods

An edentulous cast with 6 implant abutment analogs (MultiUnit Abutment Plus Replica) was digitized (T710). Five groups were created depending on the PG system used to capture complete arch implant scans: 4 extraoral PG systems, PIC (PIC System), Icam4D (Imetric), Grammee (BlueSkyBio), OxoFit (Oxo), and 1 intraoral PG device, Elite (Shining 3D) (n=30). In each group, the corresponding optical markers were placed on the implant abutment analogs of the reference cast, and 30 consecutive scans were recorded. Euclidean linear and angular measurements were obtained on the digitized reference cast and used to compare the discrepancies with the same measurements obtained on each experimental scan. One-way ANOVA and Tukey tests were used to analyze the trueness data. The Levene test was used to analyze precision values (α=.05).

Results

Significant linear trueness (P<.001) and precision (P<.001) discrepancies were found among the groups. PIC and Icam4D groups obtained significantly better linear trueness than the other PG systems, and PIC obtained the best linear precision. The linear discrepancies ranged from 17 to 30 µm. Significant angular trueness (P<.001) and precision (P<.001) differences were revealed among the groups. The Grammee obtained the best angular trueness, while PIC obtained the best angular precision. The angular discrepancies ranged from 0.17 to 0.34 degrees.

Conclusions

The PG system influenced the trueness and precision of complete arch implant scans. The intraoral PG obtained accuracy values similar to those of the 2 extraoral PGs (Grammee and OxoFit). The discrepancies measured among the systems may not be clinically significant.