Evidence map›Paper›PMID 39994614›Full record

ArticleBMC oral health2025

A micro- computed tomographic study of the anatomic danger zone in mesial roots of permanent mandibular first and second molars.

Ying Tang, Yinfeng Qiu, Panpan Zhang, Lu Wang, Juan Fan, Wenyuan Zhou, Jin Li, Yongchun Gu

Abstract read
In one paragraph

Article in BMC oral health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

8 authors.

Ying Tang *Department of Pathology, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China.
Yinfeng Qiu *Department of Dentistry, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China.
Panpan Zhang *Department of Dentistry, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China.
Lu Wang *Department of Dentistry, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China.
Juan FanDepartment of Dentistry, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China.
Wenyuan ZhouDepartment of Dentistry, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China.
Jin LiDepartment of VIP Clinic, Nanjing Medical University, Affiliated Stomatological Hospital of Nanjing Medical University, State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, 136 Hanzhong Road, Nanjing, 210029, China. lijin6806@163.com.
Yongchun GuDepartment of Dentistry, Ninth People'S Hospital of Suzhou, Soochow University, Suzhou, China. guyc7152@163.com.

Funding

Scientific Project of Ninth People's Hospital YK202235Scientific Project of Ninth People's Hospital YK202323Suzhou "Medical Health Science and Technology Innovation" Project SKY2022030
6 · The paper itself

Abstract

backgroundTo investigate the geometric characteristics of the danger zone in the mesial roots of mandibular molars using micro-computed tomography (micro-CT).

methodsA total of 75 extracted mandibular first (50 were 2-rooted [2RM1] and 25 were 3-rooted [3RM1]) and 35 2-rooted mandibular second molars (2RM2) were collected and evaluated using micro-CT. The morphological aspects of the mesial roots associated with the danger zone (the canal curvature, minimum mesial [MWT] and distal canal wall thickness [DWT], depth and level of root concavities) were evaluated. One-way analysis of variance (ANOVA) was used for multiple group comparisons. Student's t-test or paired t-test was used to test the means between two groups.

resultsAll mesial roots curved severely (81.8%, 90/110) or moderately (18.2%, 20/110) towards the furcation side, and the mean angle was 25.3 ± 7.2 degrees. The presence of a distolingual root only had limited influence on the geometricgeometry of the mesial root. In the majority of cases, the mean DWT was less than the MWT, and statistical significance (all p < 0.05) was detected at 0-3 mm (MB and ML of 3RM1), 0-4 mm (MB of 2RM1, and MB and ML of 2RM2), 0-5 mm (single mesial canals of mandibular first and second molars), and 0-6 mm (ML of 2RM1) below furcation. The mean depth of distal concavities is always greater (all p < 0.05) than the mesial ones at each root level. Generally, the mean depth of distal concavities increased apically in the cervical portion, reaching the maximum value at 2 mm below furcation, and then declined gradually in the apical portion.

conclusionsThe mesial roots of mandibular first and second molars often exhibit severe distal curvature, with a mean Schneider's angle of 25.3 degrees, and the thinnest dentin wall is typically on the distal side. Distal root concavities are significantly deeper than mesial ones, with the maximum depth generally located 2 mm below the furcation. When identifying the danger zone, factors such as DWT should not be considered in isolation. Canal curvature, distal root concavities, and the type of instrument used are also critical in affecting the likelihood and location of strip perforation, though their precise roles warrant further investigations.

Indexed as

Dental Pulp CavityMolarTooth RootX-Ray MicrotomographyHumansMandibleDanger zoneMandibular molarMesial rootMicro-computed tomographyRoot canal curvatureRoot concavity

Identifiers

PMID39994614
PMCPMC11852544

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.