Trueness and scan time for complete‐arch digital intraoral implant impression techniques and scanbodies

Abstract

Background Inaccurate transfer of the implant position can lead to an ill-fitting prosthesis, which may ultimately result in both biological and mechanical complications. Increasing the number of reference data points in an edentulous arch by modifying the surface and or topography may improve intraoral scan trueness. The effects of scanbody design and different scan techniques on the intraoral scan trueness and scan time of complete-arch implant situations is not well known. Aim/Hypothesis The purpose of this study was to investigate the effect of scanbody design and scan technique on the trueness and scan time of complete arch digital implant impressions. The null hypotheses were that different scanning techniques and scanbodies would not affect the trueness of scans and scan time. Material and Methods An edentulous acrylic resin maxillary model was fabricated with 4 implants (ZimmerBiomet Dental) evenly spaced within the arch. Five intraoral scanbodies [IO FLO Atlantis (Dentsply Implants), Core-3D, NT-Trading, Dess, ZimmerBiomet] were attached to the implants and scanned using an industrial scanner (COMET L3D, Zeiss) to produce a master stereolithography file (MSF). One intraoral scanner (Trios, 3Shape) was used to make the test digital impressions- control group with no modifications (NoM), floss tied between scan bodies (FS), glass fiduciary markers placed on the edentulous ridge (GM), and PIP paste painted on the ridge and palate (PP) (n = 5). The test scans were superimposed over MSF using metrology software and best fit algorithm. The average 3D distance deviation in scanbody position was calculated and the scan time for each test was recorded. Statistical analysis was performed using multifactorial ANOVA and Tukey's test for deviation and scan time (alpha=.05). Results Two Factor ANOVA revealed no statistically significant interaction between the effects of scanbody and technique on average 3D distance deviation (F=1.28, P = .246). Scan body and technique alone each had a significant effect on the average 3D distance deviation (P = .031 and P = 0.001). Tukey's test revealed that ZimmerBiomet showed significantly less deviation than IO FLO (P = 0.041). Floss technique showed significantly more deviation than the glass bead, PIP paste, and non-modified techniques (P = 0.008, P = 0.013, P = 0.002, respectively). Two Factor ANOVA for time revealed no statistically significant interaction between the effects of scanbody and technique on scan time (F=1.73, P = 0.076), and no significant effect of technique (P = 0.093). Statistically significant difference in the means of the scan time between the ZimmerBiomet and Dess (P = 0.017), ZimmerBiomet and NT-Trading (P < 0.001), and NT-trading and Core-3D (P = 0.004). Conclusions and Clinical Implications All scanbodies and techniques in combination with an intraoral scanner demonstrated average distance deviation greater 170 μm. Two scanbodies (ZimmerBiomet and Core 3D) enabled faster scanning, but only one of them demonstrated improved trueness (ZimmerBiomet). Clinicians may prefer the scanbody that enables scans with less implant position deviation and shorter time for efficient digital intraoral impressions of implants in complete-arch situations.