Melton D C, Krell K V, Fuller M W
Department of Endodontics, University of Iowa College of Dentistry, Iowa City.
J Endod. 1991 Aug;17(8):384-8. doi: 10.1016/S0099-2399(06)81990-4.
The mandibular second molar has many root canal variations. This investigation used two evaluation methods to examine the canal morphology of mandibular second molars having C-shaped canals. Fifteen extracted mandibular second molars with a conical root and C-shaped canal orifice were separated into two groups. A polyester cast resin technique allowed three-dimensional visualization of the root canal system in eight teeth; the remaining seven molars were prepared for histological examination in cross-section in the coronal, middle, and apical thirds for study under the light microscope. The results illustrated that C-shaped canals in mandibular second molars can vary in number and shape along the length of the root with the result that debridement, obturation, and restoration in this group may be unusually difficult.
下颌第二磨牙有许多根管变异情况。本研究采用两种评估方法来检查具有C形根管的下颌第二磨牙的根管形态。将15颗拔除的、具有锥形牙根和C形根管口的下颌第二磨牙分为两组。聚酯铸型树脂技术使8颗牙齿的根管系统得以三维可视化；其余7颗磨牙则制备成在冠部、中部和根尖三分之一处的横断面进行组织学检查，以便在光学显微镜下研究。结果表明，下颌第二磨牙的C形根管在牙根长度方向上数量和形态会有所不同，因此该组牙齿的清创、充填和修复可能异常困难。
