Eaton James A, Clement David J, Lloyd Adam, Marchesan Melissa A
Department of Endodontics, University of Tennessee Health Science Center College of Dentistry, Memphis, Tennessee.
Department of Endodontics, University of Tennessee Health Science Center College of Dentistry, Memphis, Tennessee.
J Endod. 2015 Nov;41(11):1888-91. doi: 10.1016/j.joen.2015.08.013. Epub 2015 Oct 1.
This study investigated the influence of anatomic root canal system landmarks on access outline forms of mandibular molars and correlated these to the theoretical distance of orifice relocation and changes in canal primary curvature.
Thirty relatively calcified human mandibular molars were selected and examined by micro-computed tomographic imaging. Three-dimensional volume reconstructions were made, root canal system landmarks identified, and plotted: canal orifices, canal position at the furcation level, and pulp horn location. Each landmark was separately projected onto the occlusal surface, and 3 access designs were respectively proposed: (1) minimally invasive, (2) straight-line furcation, and (3) straight-line radicular. For each access design, the theoretical distance of orifice relocation and canal primary curvature were determined. Data were submitted to 2-way repeated measures analysis of variance (α < 0.05).
The orifice relocation distance required to obtain each type of access outline was greater for radicular-based accesses (0.97 ± 0.32 mm) than for furcation accesses (0.52 ± 0.30 mm, P < .001) and resulted in a greater change in canal primary curvature (P < .001; 15.9° ± 4.6° and 9.4° ± 4.3°, respectively). The canal primary curvature for each access outline type was statistically different from each other (P < .0001), whereas the minimally invasive access showed the highest mean angle (40.1° ± 8.4°) followed by the straight-line furcation (30.7° ± 7.5°) and the straight-line radicular accesses (24.2° ± 8.4°).
The use of different landmarks to establish access outline designs affected the primary angle of curvature in relatively calcified mandibular molars.
本研究调查了解剖学根管系统标志对下颌磨牙开髓轮廓形态的影响，并将这些影响与根管口移位的理论距离以及根管初始弯曲度的变化相关联。
选取30颗钙化程度相对较高的人下颌磨牙，通过显微计算机断层扫描成像进行检查。进行三维容积重建，识别并绘制根管系统标志：根管口、根分叉水平处的根管位置以及髓角位置。将每个标志分别投影到咬合面上，并分别提出3种开髓设计：（1）微创，（2）直线至根分叉，（3）直线至牙根。对于每种开髓设计，确定根管口移位的理论距离和根管初始弯曲度。数据进行双向重复测量方差分析（α < 0.05）。
基于牙根的开髓方式（0.97 ± 0.32 mm）获得每种开髓轮廓所需的根管口移位距离大于基于根分叉的开髓方式（0.52 ± 0.30 mm，P <.001），并且导致根管初始弯曲度的变化更大（P <.001；分别为15.9° ± 4.6°和9.4° ± 4.3°）。每种开髓轮廓类型的根管初始弯曲度在统计学上彼此不同（P <.0001），而微创开髓方式的平均角度最高（40.1° ± 8.4°），其次是直线至根分叉开髓方式（30.7° ± 7.5°）和直线至牙根开髓方式（24.2° ± 8.4°）。
使用不同的标志来建立开髓轮廓设计会影响钙化程度相对较高的下颌磨牙的初始弯曲角度。
