Int J Comput Dent. 2023 Nov 28;26(4):331-337. doi: 10.3290/j.ijcd.b3839017.
The aim of the present in vitro study was to assess and compare the accuracy of two best-fit alignment strategies with different reference areas for wear measurement with an intraoral scanner (IOS).
Eight anatomic contour zirconia crowns were fabricated and scanned twice with an IOS. One of the scan datasets (Data Trueness) was duplicated and wear facets were simulated (Data Wear). The other scan dataset (Data Baseline) was aligned to Data Wear by two best-fit alignment strategies with different reference areas (the occlusal surface with no signs of wear [Group Occlusal], and the axial surface [Group Axial]), and 3D deviation analysis was performed to detect wear loss. The 3D deviation between Data Trueness and Data Wear was calculated as the truth-value for accuracy evaluation (Group Trueness).
The color-difference map showed Group Occlusal had a similar wear-facet distribution to Group Trueness while Group Axial showed an obvious tilting position, and the obtained height loss values were larger and with large standard deviations. Both Group Occlusal and Group Axial showed significant differences compared with Group Trueness in maximum height loss and mean height loss (P < 0.05) while showed no significant difference in mean distance (P > 0.05). The paired t test showed significant differences between Group Occlusal and Group Axial in maximum height loss and mean height loss (P < 0.05) while showed no significant difference in mean distance (P > 0.05).
Best-fit alignment with the occlusal reference area produced a better alignment result than that with the axial reference area. Measuring wear with an IOS has potential, but the method is prone to overestimating the height loss.
本体外研究旨在评估和比较两种最佳拟合配准策略的准确性，这两种策略使用不同的参考区域进行磨损测量，研究对象为口腔内扫描仪（IOS）。
制作了 8 个解剖轮廓氧化锆冠并使用 IOS 进行了两次扫描。其中一个扫描数据集（Data Trueness）被复制，模拟了磨损面（Data Wear）。另一个扫描数据集（Data Baseline）通过两种最佳拟合配准策略与不同的参考区域（无磨损迹象的咬合面[Group Occlusal]和轴面[Group Axial]）对齐，并进行了 3D 偏差分析以检测磨损损失。Data Trueness 和 Data Wear 之间的 3D 偏差被计算为准确性评估的真值（Group Trueness）。
色差图显示 Group Occlusal 与 Group Trueness 具有相似的磨损面分布，而 Group Axial 则显示出明显的倾斜位置，并且获得的高度损失值较大且具有较大的标准偏差。与 Group Trueness 相比，Group Occlusal 和 Group Axial 在最大高度损失和平均高度损失方面均显示出显著差异（P < 0.05），而在平均距离方面则无显著差异（P > 0.05）。配对 t 检验显示，Group Occlusal 和 Group Axial 在最大高度损失和平均高度损失方面均存在显著差异（P < 0.05），而在平均距离方面则无显著差异（P > 0.05）。
使用咬合参考区域的最佳拟合配准产生的配准结果优于使用轴参考区域的配准结果。使用 IOS 测量磨损具有潜力，但该方法容易高估高度损失。
