Sequeira Vivia, Harper Matthew T, Lilly Christa L, Bryington Matthew S
Department of Restorative Dentistry, School of Dentistry, West Virginia University, Morgantown, WA.
Department of Epidemiology and Biostatistics, School of Public Health, West Virginia University, Morgantown, WA.
J Prosthodont. 2023 Jan;32(1):54-61. doi: 10.1111/jopr.13496. Epub 2022 Mar 13.
Implants placed at variable depths may vary the amount of visible scannable surface of a scan body. Intraoral scanner technology uses advanced optical principles to record the surface of the scan body to accurately capture the implant position. The purpose of this study is to investigate the effect implant placement depth has on the accuracy of digital implant impressions using an intraoral scanner.
A partially edentulous gypsum master model was fabricated to allow the positioning of a single implant analog at different depths. Four groups were created based on the planned implant depths of 7, 6, 3, and 0 mm and corresponding visibility of the scan body at 2, 3, 6, and 9 mm. The model was digitized with a laboratory scanner for the reference scan and with an intraoral scanner to generate 15 test scans per group, with a total of 60 scans. The test scans were superimposed onto the reference scan using the best fit algorithm to analyze and measure the positional (dXYZ) and angular deviation (d⍬) of the scan body using three-dimensional metrology software. Statistical analysis was performed using a one-way ANOVA and pairwise comparison was done with a Tukey-Kramer HSD test (α = 0.05).
The one-way ANOVA of the groups for the dXYZ and dθ parameters was statistically significant (F = 11.45, p < 0.001, F = 24.04, p < 0.001). Group D (9 mm) showed the least positional deviation at 38.41 μm (95% CI 30.26; 46.56) and the least angular deviation of 0.17° (95% CI 0.12; 0.21). Group A (2 mm) showed the greatest positional deviation of 77.17 μm (95% CI 65.23; 89.11) and greatest angular deviation of 0.84° (95% CI 0.65; 1.03). The positional and angular deviation increased with increased implant depth.
The accuracy of digital impressions is influenced by the implant depth and the amount of visibility of the scan body. The trueness and precision are highest when the implant is placed at 0 mm depth with complete visibility of the scan body and decreases with subgingival implant placement.
种植体植入深度不同可能会使扫描体的可见可扫描表面面积有所差异。口内扫描仪技术利用先进的光学原理记录扫描体表面，以精确获取种植体位置。本研究旨在探讨种植体植入深度对使用口内扫描仪进行数字化种植体印模准确性的影响。
制作一个部分牙列缺失的石膏母模，以便将单个种植体代型置于不同深度。根据计划的种植体深度7、6、3和0 mm以及扫描体在2、3、6和9 mm处相应的可见性创建四组。使用实验室扫描仪对模型进行数字化扫描作为参考扫描，并使用口内扫描仪生成每组15次测试扫描，共60次扫描。使用最佳拟合算法将测试扫描叠加到参考扫描上，使用三维计量软件分析和测量扫描体的位置偏差（dXYZ）和角度偏差（d⍬）。采用单因素方差分析进行统计分析，并使用Tukey-Kramer HSD检验进行两两比较（α = 0.05）。
各实验组dXYZ和dθ参数的单因素方差分析具有统计学意义（F = 11.45，p < 0.001，F = 24.04，p < 0.001）。D组（9 mm）的位置偏差最小，为38.41μm（95%可信区间30.26；46.56），角度偏差最小，为0.17°（95%可信区间0.12；0.21）。A组（2 mm）的位置偏差最大，为77.17μm（95%可信区间65.23；89.11），角度偏差最大，为0.84°（95%可信区间0.65；1.03）。位置偏差和角度偏差随种植体深度增加而增大。
数字化印模的准确性受种植体深度和扫描体可见度的影响。当种植体植入深度为0 mm且扫描体完全可见时，真实性和精度最高，随着种植体龈下植入，其真实性和精度会降低。
