Statement of Problem: In the CAD Program accurate image matching of scan with the design of scan body is important to replicate the actual implant position. In clinical situations where the scan part of the scan body is partially submerged in gingival tissue, the influence of scan image deficiency on the accuracy of image matching is not clear. Purpose: This in vitro study aims to compare and evaluate the effects of different submergence of the scan body on the accuracy of digital implant impressions. Materials and Method:Four groups Groups control ,1,2, and 3 with different scan body exposures (Fully Exposed, 1mm, 2mm, and 3mm less exposed) were digitized with a desktop scanner, saved in STL format and transferred to CAD software, where the design of the scan body was matched to scanned image of each group. Depending on scan body design, a virtual implant was drawn. The design image of the scan body and virtual implant was extracted as a single STL file (Combined image). The image-matching process was performed 5 times for each group (n=5). The accuracy of the geometric position of virtual implant was evaluated by comparing it with standard image. The linear deviations of virtual implants were analyzed 3 dimensionally using imaging software. One-way ANOVA F test followed by Tukey’s post hoc test was used to verify the effects of scan body exposure on image matching. Result: The meanlinear deviation of group 1 (36.6 +/- 8.2 microns ) and group 2 (31.4+/-7.14) was statistically not significant than control group (19 +/- 5.87) whereas it was statistically significant for group 3 (56.4+/-15.04 ) Conclusion: Submergence of scan body of more than 2mm influenced virtual implant positioning in software program

Scan Body, Exposure, Accuracy, Digital, Implant, Impression