下颌磨牙近中根不同锥度整形后牙本质保存及应力分布的显微ct及有限元分析。

IF 3.6 2区医学 Q1 DENTISTRY, ORAL SURGERY & MEDICINE

Journal of endodontics Pub Date : 2025-10-01 DOI:10.1016/j.joen.2025.06.017

Mario Alovisi DDS, PhD , Andrea Baldi DDS, PhD , Edoardo Moccia DDS, PhD , Ivan Gaviglio PhD , Allegra Comba DDS, PhD , Lia Giordano DDS , Nicola Scotti DDS, PhD , Damiano Pasqualini DDS

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引用次数: 0

摘要

摘要本研究采用微计算机断层扫描（micro-CT）和有限元分析（FEA）对不同锥度的下颌磨牙近中根整形后的牙本质保存和抗骨折性进行了评价。方法：选择48颗下颌第一磨牙，均有独立的近中牙管。中舌和中颊管随机分配（n=12）至ProTaper Gold （PG）、ProTaper Next （PTN）、ProTaper Ultimate （PU）和B4U器械系统。整形前后进行微ct扫描比较根管体积和颈牙本质体积。在分析的冠状点、中尖点和“危险区”分岔点以下，分析中根管的质心位移和牙本质去除的百分比和分布。测量近中根管远端和近中端残余牙本质厚度。采用有限元法建立了下颌磨牙近中根的线性弹性模型，并对根管冠状面施加200N的垂直载荷。采用Bonferroni校正和事后Tukey-Kramer检验的单因素方差分析（P < 0.05）。结果：与PG系统相比，B4U系统的平均牙本质体积去除量有统计学意义（P < 0.05）。B4U组的根管定心能力在冠状和中三分之一处更加突出，而PG组的根管定心能力变化更大（P < 0.05）。B4U通过根近端和远端整形后，冠状点及危险区残留牙本质厚度均有统计学差异（P< 0.05）。PG在冠状根管中去除的牙本质更多（P0.05）。结论：根管锥度的减小可以提高器械的定心能力和对残留牙本质组织的保护，特别是在冠状和中三分之一。根管的锥度似乎不影响下磨牙近中根的应力分布模式。

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Micro-CT and Finite Element Analysis of Dentin Preservation and Stress Distribution in Mesial Roots of Mandibular Molars after Shaping with Different Tapers

Introduction

The aim of this study was to evaluate the dentin preservation and fracture resistance of mandibular molar mesial roots after shaping with different tapers using micro–computed tomography (micro-CT) and finite element analysis (FEA).

Methods

Forty-eight mandibular first molars with independent mesial canals were selected. The mesio-lingual and mesio-buccal canals were randomly assigned (n = 12) to ProTaper Gold (PG), ProTaper Next (PTN), ProTaper Ultimate (PTU), and B4U instrumentation systems. Pre- and post-shaping micro-CT scans were performed to compare root canal volume and cervical dentin volume. The centroid shift and the percentage and distribution of the dentin removal in correspondence of the mesial canals were analyzed in coronal, middle, and apical points of analysis and below the furcation at the “danger zone.” The residual dentin thickness in the distal and mesial aspects of the mesial canals was measured. A linear elastic model of a mesial root of a mandibular molar was created through the finite element method (FEM) and a 200N perpendicular load was applied on the root canal coronal third. One-way factorial analysis of variance with Bonferroni correction and post hoc Tukey-Kramer tests were used (P < .05).

Results

The mean cervical dentin volume removal was statistically lower for the B4U compared with the PG system (P < .05). The canal centering ability was statistically more accentuated for the B4U group in the coronal and middle third and higher centroid shift variations occurred for PG system (P < .05). The residual dentin thickness appeared statistically higher after shaping with B4U through the mesial and distal root aspect at the coronal point of analysis and at the danger zone (P < .05). PG removed more dentin in the coronal root canal third (P < .05). The FEM analysis showed no statistically significant differences between groups (P > .05).

Conclusions

The reduction of the root canal taper may improve the instruments’ centering ability and the preservation of the residual dentin tissue, especially in the coronal and middle third. The root canal taper seems not to influence the stress distribution pattern through the mesial root of the lower molars.

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来源期刊

Journal of endodontics 医学-牙科与口腔外科

CiteScore

8.80

自引率

9.50%

发文量

224

审稿时长

42 days

期刊介绍： The Journal of Endodontics, the official journal of the American Association of Endodontists, publishes scientific articles, case reports and comparison studies evaluating materials and methods of pulp conservation and endodontic treatment. Endodontists and general dentists can learn about new concepts in root canal treatment and the latest advances in techniques and instrumentation in the one journal that helps them keep pace with rapid changes in this field.