Rapp R, Matthews G, Simpson M, Pashley D H
Dental Medicine Research Office, School of Dental Medicine, University of Pittsburgh, PA, USA.
J Endod. 1992 Sep;18(9):444-7. doi: 10.1016/S0099-2399(06)80846-0.
Extracted unerupted permanent third molars with the occlusal half of the crown and apical half of the roots removed were cemented to Plexiglas blocks. Using a positive pressure system in which the movement of fluid across the dental tubules could be measured, the permeability of furcation dentin was measured before and after alteration of the furcation thickness. Subsequently, measurements of reduction in thickness of cementum and dentin were performed. Furcation dentin permeability was found to increase as the cementum and dentin thickness was reduced and the smear layer removed. The permeability values obtained for the furcation dentin were similar to those found in radicular dentin in general, indicating that root dentin has a low permeability and that it has good barrier properties. The data would suggest that any bone resorption seen under the furcation region of permanent molars is more likely to be due to the presence of accessory canals than due to permeation directly through furcation hard tissues.
将拔除的未萌出恒第三磨牙，去除牙冠咬合面一半和牙根根尖一半后，粘结到有机玻璃块上。使用正压系统测量液体穿过牙本质小管的移动情况，在改变根分叉厚度前后测量根分叉牙本质的渗透性。随后，进行牙骨质和牙本质厚度减少量的测量。发现随着牙骨质和牙本质厚度减少以及玷污层去除，根分叉牙本质渗透性增加。根分叉牙本质获得的渗透值总体上与根管牙本质中的渗透值相似，表明牙根牙本质渗透性低且具有良好的屏障特性。数据表明，在恒磨牙根分叉区域下方看到的任何骨吸收更可能是由于副根管的存在，而不是直接通过根分叉硬组织渗透所致。
