Department of Restorative Dentistry, Faculty of Dentistry, University of Debrecen Medical and Health Science Center, Debrecen, Hungary.
Department of Biomaterials and Prosthetic Dentistry, Faculty of Dentistry, University of Debrecen Medical and Health Science Center, Debrecen, Hungary.
Biomed Res Int. 2019 Jul 2;2019:9758176. doi: 10.1155/2019/9758176. eCollection 2019.
The objective of this study was to analyse the effectiveness of some parameters which characterise the change in morphology in human root canals subjected to ProTaper rotary enlargement with the help of an X-ray microfocus computed tomography (MCT) and to introduce a novel parameter that is effective in quantifying changes in root canal morphology. Ten each straight and curved root canals with mature apices chosen from extracted human upper incisor and canine teeth were scanned with MCT before and after canal shaping using ProTaper rotary instruments in order to facilitate three-dimensional digital reconstruction and quantitative gauging of relevant instrumental parameters and changes therein (surface area and volume). Root canal geometry change and the effectiveness of shaping were quantified with Structure Model Index change (ΔSMI) and surface area change to volume change ratio (ΔSA/ΔV). These two parameters were also tested on simulated canals. Postinstrumentation cross-sectional changes were also analysed, but only on the plastic blocks. Statistical analysis of parameters was carried out to verify the significance of results. Analysis of cross-sectional shape of postinstrumented resin simulated canals showed statistically significant decrease in Form Factor (p<0.05) and statistically significant increase in Eccentricity (p<0.005). ΔSMI did not show significant difference between straight and curved canals. SMI values showed bidirectional change during root enlargement which questions the reliability of this metric in analysing instrumentation. Statistically significant (p<0.005) deviations in ΔSA/ΔV were quantified as 1.92 and 3.22 for straight and curved human canals, respectively. Instrumentation-induced canal geometry change was determined to be more pronounced in curved canals using the novel parameter ΔSA/ΔV. This has been proven as being a statistically accurate and reproducible parameter for quantitative characterisation of root canal geometry change and differentiation of preparational efficacy for both straight and curved root canals.
本研究的目的是分析 ProTaper 旋转扩大过程中一些特征根管形态变化的参数的有效性，借助 X 射线微焦点计算机断层扫描（MCT），并引入一种新的参数，该参数有效地量化根管形态的变化。从提取的人上颌中切牙和尖牙中选择了 10 个直形和弯曲根管，每个根管均具有成熟根尖，使用 MCT 在使用 ProTaper 旋转器械进行根管成形前后进行扫描，以便于进行三维数字重建和对相关器械参数及其变化（表面积和体积）进行定量测量。使用结构模型指数变化（ΔSMI）和表面积变化与体积变化的比值（ΔSA/ΔV）来量化根管几何形状的变化和成形的效果。这两个参数也在模拟根管上进行了测试。还分析了器械后横截面的变化，但仅在塑料块上进行。对参数进行了统计分析，以验证结果的显著性。对器械后树脂模拟根管的横截面形状进行分析，发现形态因子（Form Factor）显著降低（p<0.05），偏心度（Eccentricity）显著增加（p<0.005）。直形和弯曲根管之间的 ΔSMI 没有显著差异。在根管扩大过程中，SMI 值显示出双向变化，这使得该指标在分析器械处理时的可靠性受到质疑。直形和弯曲的人根管分别定量了 1.92 和 3.22 的显著（p<0.005）的 ΔSA/ΔV 偏差。使用新参数 ΔSA/ΔV 确定器械诱导的根管几何形状变化在弯曲根管中更为明显。这已被证明是一种统计上准确且可重复的参数，用于定量描述根管几何形状的变化，并区分直形和弯曲根管的预备效果。
