口腔医学研究

口腔医学研究 ›› 2022, Vol. 38 ›› Issue (12): 1161-1166.DOI: 10.13701/j.cnki.kqyxyj.2022.12.012

• 牙体修复学研究 • 上一篇    下一篇

不同牙本质肩领和冠根比对不同桩核材质修复后前磨牙残根抗力影响的实验研究

陈雨昕1,2,3, 李迎梅2, 杜琛2, 徐志铭2, 孟庆飞1,2,3*, 孟箭1,2,3*   

  1. 1.徐州医科大学徐州临床学院 江苏 徐州 221000;
    2.徐州市中心医院口腔科 江苏 徐州 221000;
    3.徐州医科大学口腔医学院 江苏 徐州 221000
  • 收稿日期:2022-04-24 出版日期:2022-12-28 发布日期:2022-12-26
  • 通讯作者: *孟庆飞,E-mail:1981mqf@163.com;孟箭,E-mail:mrocket@126.com
  • 作者简介:陈雨昕(1997~ ),女,江苏无锡人,住院医师,硕士在读,研究方向:残根残冠的保存修复。
  • 基金资助:
    国家口腔疾病临床医学研究中心开放性课题(编号:NCRCO-202101);江苏省科研与实践创新计划项目(编号:730221034);江苏省“六个一工程”拔尖人才(编号:LGY2020027)

Influence of Ferrule Heights and Crown-to-root Ratios on Fracture Resistance of Residual Roots Restored with Different Post-and-core Systems in Vitro

CHEN Yuxin1,2,3, LI Yingmei2, DU Chen2, XU Zhiming2, MENG Qingfei1,2,3*, MENG Jian1,2,3*   

  1. 1. Xuzhou Clinical College, Xuzhou Medical University, Xuzhou 221000, China;
    2. Department of Stomatology, Xuzhou Central Hospital, Xuzhou 221000, China;
    3. College of Stomatology, Xuzhou Medical University, Xuzhou 221000, China
  • Received:2022-04-24 Online:2022-12-28 Published:2022-12-26

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摘要： 目的: 探讨不同牙本质肩领与冠根比值对前磨牙残根经铸造或纤维桩核修复后抗折力的影响。方法: 选取80颗完整单根管下颌第一前磨牙,将牙冠自颊侧釉牙骨质界上方2.0 mm处切除,形成的残根模型为水平型,并对其进行常规根管预备及根管充填。80颗残根随机均分成A、B两组,每组再均分为5个小组,分别记为A0~A4组、B0~B4组。A组为纤维桩核修复,其中A0组为无肩领组,在A1~A4组残根颈部分别通过模拟冠延术制备1.0~4.0 mm高的牙本质肩领。B组为铸造桩核修复,B0~B4组肩领设计同A组。所有样本均采用钴铬合金全冠修复。自冠颈缘根方2.0 mm将样本埋于自凝树脂块内。以自凝树脂包埋平面为界计算各组试件的临床冠根比值依次为0.62(A0、B0组)、0.75(A1、B1组)、0.91(A2、B2组)、1.10(A3、B3组)和1.33(A4、B4组)。将试件放置于试验机上,与牙长轴根方成135°、以1.0 mm/min的加载速度,在颊尖顶加载至试件出现折裂,记录折裂时最大载荷及断裂模式并进行统计学分析。结果: 各组折裂载荷均值(kN)分别为:A0(0.54±0.09)、A1(1.03±0.11)、A2(1.06±0.17)、A3(0.85±0.11)、A4(0.57±0.10);B0(0.55±0.09)、B1(0.88±0.13)、B2(1.08±0.17)、B3(1.05±0.18)、B4(0.49±0.09)。肩领/冠根比可显著影响残根抗折力(P＜0.05),桩核材质对牙体抗力的影响无统计学差异(P＞0.05),但两者间存在协同作用(P＜0.05)。根据线性回归方程,A组残根折裂载荷达峰值的肩领和冠根比分别为1.92 mm和0.90,B组则为2.07 mm和0.92。结论: 在残根颈部预备一定高度牙本质肩领并行铸造或纤维桩核修复时,应使桩核冠修复后牙齿的临床冠根比在0.90~0.92以内,以提高牙齿的抗折力。

关键词: 冠根比, 牙本质肩领, 残根, 抗折力, 桩核系统

Abstract: Objective: To investigate the effect of different ferrule heights and crown-to-root ratios on the fracture resistance of premolar residual roots restored with cast or fiber post-and-core systems. Methods: Eighty sound mandibular first premolars with completely single root canal were selected, and the crowns were cut from 2.0 mm above the buccal cemento-enamel junction. The horizontal residual root models were carried out after root canal treatment. All 80 roots were randomly divided into groups A and B, and each group was divided into five subgroups, named as subgroups A0 to A4 and B0 to B4, respectively, with 8 roots each. The roots in group A were restored with prefabricated fiber post and core system, with no ferrule designs in subgroup A0. A1-A4 subgroups were designed with the ferrule height varying from 1.0 to 4.0 mm, respectively in the cervical roots by simulated surgical crown-lengthening methods. The roots in group B were given cast post and core restoration, and the ferrule designs in subgroups B0-B4 were the same as those in group A. All samples were restored with metal crowns and the teeth were embedded in an acrylic resin block to the height from the apical foramen to 2.0 mm below the crown margin. The clinical crown-to-root ratios of all subgroups were calculated as 0.62(A0, B0), 0.75(A1, B1), 0.91(A2, B2), 1.10(A3, B3), and 1.33(A4, B4), respectively. The specimen was placed on the universal mechanical machine and loaded to fracture at 135° to its long axis at a speed of 1.0 mm/min. The maximum loading values and fracture modes were recorded and analyzed statistically. Results: Mean fracture loads (kN) for subgroups A0 to A4 and B0 to B4 were as follows: 0.54 (0.09), 1.03 (0.11), 1.06 (0.17), 0.85 (0.11), 0.57 (0.10), 0.55 (0.09), 0.88 (0.13), 1.08 (0.17), 1.05 (0.18), and 0.49 (0.09). "Ferrule/crown-to-root ratio" could significantly affect the fracture resistance of residual roots (P<0.05) and there was no significant difference for the effect of "post material" (P>0.05), but there was a synergistic effect between two factors (P<0.05). According to the cox linear logistic regression, when the loading fracture reached the maximum, the ferrule length and crown-to-root ratio in group A were 1.92 mm and 0.90, while those in group B were 2.07 mm and 0.92, respectively. Conclusion: When a certain height of ferrule is prepared and cast or fiber post system is restored for the residual root, the clinical crown-to-root ratio of the tooth after restoration should be kept within 0.90 to 0.92, so as to improve the fracture resistance of the tooth.

Key words: crown-to-root ratio, ferrule, residual roots, fracture resistance, post and core system