J Am Dent Assoc. 2020 Feb;151(2):127-135. doi: 10.1016/j.adaj.2019.10.022. Epub 2019 Dec 26.
The authors evaluated the local accuracy of intraoral scanning (IOS) systems for single-tooth preparation impressions with an in vitro setup.
The authors digitized a mandibular complete-arch model with 2 full-contour crowns and 2 multisurface inlay preparations with a highly accurate reference scanner. Teeth were made from zirconia-reinforced glass ceramic material to simulate toothlike optical behavior. Impressions were obtained either conventionally (PRESIDENT, Coltène) or digitally using the IOS systems TRIOS 3 and TRIOS 3 using insane scan speed mode (3Shape), Medit i500, Version 1.2.1 (Medit), iTero Element 2, Version 1.7 (Align Technology), CS 3600, Version 3.1.0 (Carestream Dental), CEREC Omnicam, Version 4.6.1, CEREC Omnicam, Version 5.0.0, and Primescan (Dentsply Sirona). Impressions were repeated 10 times per test group. Conventional (CO) impressions were poured with type IV gypsum and digitized with a laboratory scanner. The authors evaluated trueness and precision for preparation margin (MA) and preparation surface (SU) using 3-dimensional superimposition and 3-dimensional difference analysis method using (95% - 5%) / 2 percentile values. Statistical analysis was performed using Kruskal-Wallis test. Results were presented as median (interquartile range) values in micrometers.
The authors found statistically significant differences for MA and SU among different test groups for both trueness and precision (P < .05). Median (interquartile range) trueness values ranged from 11.8 (2.0) μm (CO) up to 40.5 (10.9) μm (CEREC Omnicam, Version 5.0.0) for SU parameter and from 17.7 (2.6) μm (CO) up to 55.9 (15.5) μm (CEREC Omnicam, Version 5.0.0) for MA parameter.
IOS systems differ in terms of local accuracy. Preparation MA had higher deviations compared with preparation SU for all test groups.
Trueness and precision values for both MA and SU of single-unit preparations are equal or close to CO impression for several IOS systems.
作者通过体外设置评估了用于单颗牙预备印模的口内扫描（IOS）系统的局部准确性。
作者使用高度精确的参考扫描仪对具有 2 个全冠和 2 个多面嵌体预备的下颌全弓模型进行数字化。牙齿由氧化锆增强玻璃陶瓷材料制成，以模拟类似牙齿的光学行为。采用传统方法（PRESIDENT，Coltène）或使用 IOS 系统 TRIOS 3 和采用疯狂扫描速度模式的 TRIOS 3（3Shape）、Medit i500，版本 1.2.1（Medit）、iTero Element 2，版本 1.7（Align Technology）、CS 3600，版本 3.1.0（Carestream Dental）、CEREC Omnicam，版本 4.6.1、CEREC Omnicam，版本 5.0.0 和 Primescan（登士柏西诺德）进行数字化。每个测试组重复印模 10 次。采用 IV 型石膏对传统印模（CO）进行浇铸，并使用实验室扫描仪进行数字化。作者使用三维叠加和三维差异分析方法，采用（95%-5%）/2 百分位值，评估预备边缘（MA）和预备表面（SU）的准确性和精密度。使用 Kruskal-Wallis 检验进行统计分析。结果以微米为单位表示为中位数（四分位距）值。
作者发现不同测试组在 MA 和 SU 方面的准确性和精密度存在统计学差异（P<0.05）。SU 参数的准确性中位数（四分位距）值范围为 11.8（2.0）μm（CO）至 40.5（10.9）μm（CEREC Omnicam，版本 5.0.0），MA 参数的准确性中位数（四分位距）值范围为 17.7（2.6）μm（CO）至 55.9（15.5）μm（CEREC Omnicam，版本 5.0.0）。
IOS 系统在局部准确性方面存在差异。与所有测试组的 SU 相比，MA 的偏差更高。
对于几种 IOS 系统，单颗牙预备的 MA 和 SU 的准确性和精密度值与 CO 印模相等或接近。
