Influence of Implant Placement Depth on Implant Position Reproducibility : Comparison between Silicone Impression and Intraoral Scanner-assisted Optical Impression Methods

<p>In this study, three types of jaw models were fabricated with different implant depths, and the three-dimensional accuracy of the scan body was compared between the conventional silicone impression and intraoral scanner-assisted optical impression methods.</p><p>Three master models were fabricated by implanting the dental implant in 22 (maxillary left incisor) defect models at 1.0 mm, 3.0 mm, and 5.0 mm below the gingival margin, respectively. Subsequently, the scan body was attached to the implant of the master model, and basic data were scanned with a dental lab scanner. Further, using the conventional open tray method, the implant work models were fabricated and fitted with scan bodies ; the data were scanned using the dental lab scanner (WM-1, WM-3, WM-5, n＝5). Furthermore, using three types of intraoral scanners, namely Medit i700 (M7), Trios3 (T3), and Primescan (PS), optical impressions of the master models were obtained (M7-1, T3-1, PS-1, M7-3, T3-3, PS-3, M7-5, T3-5, PS-5, n＝5). The scanning data were imported into 3D analysis software, and superimposed with WM, M7, T3, and PS at the same implant depth and compared.</p><p>The concordance rates of M7, T3, and PS were significantly higher than those of WM at all implant depths ; the amounts of displacement of M7, T3, and PS were smaller than that of WM in color mapping. As the implant depth increased, the concordance rates of WM decreased, while the interquartile range increased.</p><p>Thus, the implant-position reproducibility of the silicone impression method decreased significantly when the implant depth was 5.0 mm below the gingival margin ; however, the optical impression method using various intraoral scanners showed high implant-position reproducibility.</p>