Mol A, van der Stelt P F
Department of Oral Radiology, Academic Center for Dentistry, Amsterdam, The Netherlands.
Oral Surg Oral Med Oral Pathol. 1993 Mar;75(3):373-82. doi: 10.1016/0030-4220(93)90154-v.
An algorithm was designed to automatically obtain information on the orientation of roots in dental radiographs aimed at localizing the periapical region. A curve was approximated mathematically by a cubic polynomial to intersect the boundary of the root at its apex. The performance was judged by comparing the location of this intersection with the actual location of the apex as determined by five expert observers. In an experiment with 262 roots of the eight tooth groups, the distance between these two points was less than 1 mm in 67.9% of all cases and less than 2 mm in 88.2%. The performance of the procedure appeared to depend on the tooth group (p < 0.01). The location of the intersection was reproducible within 1 mm in 86.4% of all cases. The reproducibility was, however, not equal for all tooth groups (p < 0.01). The experts were more consistent in localizing the apex than the system was (p < 0.01), although this difference was not confirmed for four of the tooth groups (p > 0.57), and was marginal for two others (0.01 < p < 0.02). It is concluded that the algorithm is promising in its capacity to track a majority of roots down to their apex. It could therefore add important knowledge to imaging procedures aimed at the digital analysis of the periapical region.
设计了一种算法，旨在自动获取牙科X光片中牙根的方向信息，以定位根尖区域。用三次多项式对曲线进行数学逼近，使其在根尖处与牙根边界相交。通过将该交点的位置与由五名专家观察者确定的根尖实际位置进行比较来判断性能。在对八组牙齿的262个牙根进行的实验中，这两个点之间的距离在所有病例的67.9%中小于1毫米，在88.2%中小于2毫米。该程序的性能似乎取决于牙齿组（p < 0.01）。在所有病例的86.4%中，交点的位置可在1毫米内重复。然而，所有牙齿组的重复性并不相同（p < 0.01）。专家在定位根尖方面比该系统更一致（p < 0.01），尽管其中四组牙齿未证实存在这种差异（p > 0.57），另外两组差异很小（0.01 < p < 0.02）。结论是，该算法在追踪大多数牙根至根尖的能力方面很有前景。因此，它可以为旨在对根尖区域进行数字分析的成像程序增添重要知识。
