Influence of customized over-scan body rings on the intraoral scanning effectiveness of a multiple implant edentulous mandibular model.

ABSTRACT

OBJECTIVES: To evaluate the effectiveness of intraoral scanning with identical multiple implant scan bodies (ISB) using customized over scan body rings (COR) as an auxiliary system. METHODS: Six printed rings with different diameters and shapes were attached at different levels to each identical ISB of an edentulous mandibular master model. The master model was scanned using an intraoral scanner (Primescan CEREC) until valid digital models for the COR group (n=10) and for the unmodified ISB (UN) group (n=10) were obtained. The total scanning times and the number of rescans required was registered. To assess differences between scanning efficiency the Student T-test and Mann Whitney U-Test were applied. A Coordinate Measuring Machine (CMM) was used to register the reference model. To evaluate accuracy discrepancies between the test scans (n=20) and the reference model, Geomagic Control X was used. Mann Whitney U-test was applied to calculate statistically significant differences. RESULTS: To achieve a valid model, an average of 4.70 rescans / repetitions were required for the UN group, whereas for the COR group required an average of 1.40 rescans (p<.001). Mean total scanning time was 201.10 s and 542.40 s for the COR and UN group, respectively (p=.001). No statistically significant differences were found between the groups in terms of accuracy (p>.05) with respectively COR and UN values; mean linear trueness 34.38 µm and 31.14 µm, mean linear precision 22.94 µm and 18.51 µm, mean angular trueness 0.12° and 0.14°, mean angular precision 0.075° and 0.08°. CONCLUSION: The use of the COR system may increase the scanning efficiency of multiple implants with similar ISBs without impacting the accuracy.