Department of Cariology and Endodontics, School of Dentistry, University of Copenhagen, Copenhagen, Denmark.
Acta Odontol Scand. 2012 Mar;70(2):133-9. doi: 10.3109/00016357.2011.600707. Epub 2011 Jul 25.
The purpose of this study was to investigate the scanning and segmentation precision of surface models of molars for the detection of small volumes, such as the reduced pulp cavity; formation of mineral deposits; detection of narrow root canals and to improve the clinical and morphological understanding of the number of root canals and their configuration.
Eighteen human molars were scanned using X-ray micro-computed tomography. The reconstruction of the surface models had a precision of <1 voxel, using three-dimensional software and quantitative color mapping. In order to relate the measurements to changes over time the size of the pulp chambers was classified in two well-defined groups.
The mineral deposits were more evenly distributed in small pulp chambers than in large, but complete root canal calcification was never observed. No difference was observed in the material with respect to the presence of intra-radicular connections. In upper molars, a second mesiobuccal canal (mb(2)) frequency of 91% was found. The difference in length between the first mesiobuccal canal (mb(1)) and mb(2) was <1 mm. The number of root canals could be related to the number of root cones.
In summary, three-dimensional surface models were made with a high precision; an increased accumulation of mineral deposits was noted in molars with small pulp chambers and combined with the consistent pattern of intra-radicular connections, the potential endodontic treatment complexity is underlined in such cases. Finally, an improved understanding of root canal prevalence was reached, when merging well-defined definitions on root morphology and clinical classification systems.
本研究旨在探讨磨牙表面模型扫描和分割的精度，以检测小体积，如缩小的牙髓腔；矿物质沉积的形成；检测狭窄的根管，并提高对根管数量和形态的临床和形态学理解。
使用 X 射线微计算机断层扫描对 18 个人类磨牙进行扫描。使用三维软件和定量彩色映射，表面模型的重建精度<1 体素。为了将测量结果与时间相关联，将牙髓腔的大小分为两个明确的组。
矿物质沉积在小牙髓腔中的分布比在大牙髓腔中更均匀，但从未观察到完全的根管钙化。在根管内连接的存在方面，材料没有差异。在上颌磨牙中，发现第二近中颊根管（mb(2)）的频率为 91%。第一近中颊根管（mb(1)）和 mb(2)之间的长度差异<1 毫米。根管数量与根管锥数量有关。
总之，用高精度制作了三维表面模型；在牙髓腔较小的磨牙中，矿物质沉积增加，加上根管内连接的一致模式，强调了在这种情况下潜在的牙髓治疗复杂性。最后，通过将明确的根管形态定义和临床分类系统相结合，达到了对根管流行率的更好理解。
