Influence of the surface humidity, implant angulation, and interimplant distance on the accuracy and scanning time of complete-arch implant scans

Objectives: To assess the influence of implant angulation, humidity, and interimplant distance on the accuracy and scanning time of complete-arch implant scans.Methods: A definitive cast with 4 parallel implant abutment analogs (P group), and another cast with 4 angulated (up to 30 degrees) implant abutment analogs (NP group) were digitized by using a scanner (7Series) (reference scans). Two subgroups were created: dry (D subgroup) and wet (W subgroup). For the D subgroup, the casts were digitized without altering the surface humidity by using an intraoral scanner (IOS) (TRIOS 3). For the W sub-group, the cast surface was humidified with artificial saliva and digitized by using the same IOS. The interimplant distance discrepancies were assessed by computing linear and angular measurements. Trueness data was analyzed using 3-way ANOVA followed by the pairwise comparison Tukey tests. The Bartlett test, followed by the pairwise comparison tests, was used to assess the precision (alpha=.05).Results: Regarding the trueness, implant angulation (P<.001) and inter-implant distance measurement (P<.001) influenced the linear discrepancies. Implant angulation (P=.002), humidity conditions (P<.001), and inter -implant distance (P=.001) influenced the angular discrepancies. Regarding the precision, significant differ-ences in the variance of linear and angular measurements and inter-implant distances were found. Humidity conditions (P<.001) influenced the scanning time.Conclusions: Implant angulation, humidity, and interimplant distance influenced the accuracy and scanning time of complete-arch implant scans. Parallel implants resulted in higher trueness and precision values. Dry conditions resulted in slightly higher scanning trueness and precision and shorter scanning time. Clinical significance: Drying the surface being scanned increases intraoral scanning accuracy and decreases intraoral scanning time.