Olivieri Juan Gonzalo, Duran-Sindreu Fernando
Department of Endodontics, Universitat Internacional de Catalunya, Barcelona, Spain.
Eur Endod J. 2018 Nov 21;3(3):160-166. doi: 10.14744/eej.2018.96158. eCollection 2018.
The purposes of the present study were to evaluate dentine thickness and concavity depth below the furcation level of the mesial canals of the mandibular first and second molars, to examine differences between gender, age, and quadrant, and to prove if there is a relationship between root length and dentine thickness.
Two hundred eleven mandibular first and second molars were included in this study. Samples were divided according to age, gender, quadrant, and root length. Measurements of dentine thickness from the external border of the root canal to the external root surface and concavity depth were recorded 1, 2, and 4 mm below the furcation level. Kruskal-Wallis and Wilcoxon rank sum tests were performed to estimate the influence of different variables, and a multiple regression analysis was performed to evaluate the influence of dentine thickness below the furcation level.
First molars had a deeper concavity depth with significant differences in both 1 mm and 2 mm levels than second molars (P<0.05). According to concavity depth, there was no relationship with teeth length (P>0.05). The distal concavity was significantly deeper in the 1 and 2 mm levels (P<0.05). According to gender, the female group had a reduced dentine thickness in both mesiolingual and mesiobuccal canals in both 1 mm and 2 mm levels (P<0.05).
Female patients have a reduced dentine thickness below the furcation level. In order to select the most appropriate instrumentation procedure in every specific case, clinicians must be aware of the dentine reduced thickness measurements to avoid procedural iatrogenic damage.
本研究旨在评估下颌第一和第二磨牙近中根管分叉水平以下的牙本质厚度和凹陷深度，研究性别、年龄和象限之间的差异，并验证牙根长度与牙本质厚度之间是否存在关系。
本研究纳入了211颗下颌第一和第二磨牙。样本根据年龄、性别、象限和牙根长度进行划分。记录在分叉水平以下1、2和4毫米处从根管外边界到牙根外表面的牙本质厚度测量值以及凹陷深度。进行Kruskal-Wallis和Wilcoxon秩和检验以评估不同变量的影响，并进行多元回归分析以评估分叉水平以下牙本质厚度的影响。
第一磨牙的凹陷深度比第二磨牙更深，在1毫米和2毫米水平处均存在显著差异（P<0.05）。根据凹陷深度，与牙长无相关性（P>0.05）。在1毫米和2毫米水平处，远中凹陷明显更深（P<0.05）。按性别划分，女性组在1毫米和2毫米水平处的近中舌侧和近中颊侧根管中的牙本质厚度均减小（P<0.05）。
女性患者在分叉水平以下的牙本质厚度减小。为了在每个具体病例中选择最合适的器械操作程序，临床医生必须了解牙本质厚度减小的测量值，以避免操作中的医源性损伤。
