Tahani Bahareh, Rashno Abdolreza, Haghighi Hamed, Monirifard Rasoul, Khomami Hooman Nosrati, Kafieh Rahele
Department of Dental Public Health, Dental Research Center, Dental Research Institute, Isfahan University of Medical Sciences, Khorramabad, Iran.
Department of Computer Engineering, Faculty of Engineering, Lorestan University, Khorramabad, Iran.
J Med Signals Sens. 2020 Nov 11;10(4):239-248. doi: 10.4103/jmss.JMSS_5_20. eCollection 2020 Oct-Dec.
This study presents a new and innovative experimental method, including software and its prerequisite instruments, to use image processing techniques for crown preparation analysis.
A platform was designed and constructed to take images from artificial teeth in different angles and directions and to process and analyze them by the proposed method to evaluate the quality and quantity of crown preparation. For each tooth, two series of images were taken from the artificial teeth before and after preparation, and image series were registered by two semi-automated and automated methods to transform them into one coordinate system. Region of interest was segmented by user interaction, and tooth region was segmented by substeps such as transformation to hue, saturation, and value color space, edge detection, morphology operations, and contour extraction. Finally, the amount and angle of crown preparation were computed and compared with standard measures to evaluate the quality of crown preparation. The proposed method was applied to a local dataset collected from Isfahan University of Medical Sciences.
Difference between the angle of crown preparation computed by the proposed method and that of the experts showed a mean absolute error of 7.17°. The correlation between the segmented regions by the proposed method and those of the experts was also evaluated by the Intersection over Union (IOU) criterion. The best and worst performances achieved in cases by IOU were 0.94 and 0.76, respectively. Finally, the segmentation results of the proposed method indicated an average IOU of 0.89 in all images.
Students can use this method as an assessment tool in preclinical tooth preparation to compare their crown work with standard parameters.
本研究提出了一种全新的创新实验方法，包括软件及其所需仪器，用于利用图像处理技术进行牙冠预备分析。
设计并构建了一个平台，从不同角度和方向拍摄人造牙齿的图像，并通过所提出的方法对其进行处理和分析，以评估牙冠预备的质量和数量。对于每颗牙齿，在预备前后从人造牙齿拍摄两组图像系列，并通过两种半自动和自动方法对图像系列进行配准，将它们转换到一个坐标系中。通过用户交互分割感兴趣区域，并通过诸如转换到色相、饱和度和明度颜色空间、边缘检测、形态学操作和轮廓提取等子步骤分割牙齿区域。最后，计算牙冠预备的量和角度，并与标准测量值进行比较，以评估牙冠预备的质量。所提出的方法应用于从伊斯法罕医科大学收集的本地数据集。
所提出的方法计算出的牙冠预备角度与专家计算的角度之间的差异显示平均绝对误差为7.17°。还通过交并比（IOU）标准评估了所提出的方法分割的区域与专家分割的区域之间的相关性。IOU在不同情况下取得的最佳和最差性能分别为0.94和0.76。最后，所提出的方法的分割结果表明所有图像的平均IOU为0.89。
学生可以将此方法用作临床前牙齿预备的评估工具，将他们的牙冠制备工作与标准参数进行比较。
