Evidence map›Paper›PMID 42897518›Full record

SynthesisBMC oral health2026

Comparative evaluation of dentin microcrack formation after root canal preparation with different nickel-titanium instrument systems based on micro-CT: a systematic review and meta-analysis.

Ang Li, Jimin Zhang, Yijun Lin, Huiying Dai, Feiyang Guo, Min Nie

Abstract readSystematic ReviewMeta-AnalysisComparative Study
In one paragraph

Synthesis in BMC oral health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Ang LiThe State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, Hubei, 430079, China.
Jimin ZhangThe State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, Hubei, 430079, China.
Yijun LinThe State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, Hubei, 430079, China.
Huiying DaiThe State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, Hubei, 430079, China.
Feiyang GuoCenter for Evidence-Based Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
Min NieThe State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, Hubei, 430079, China. niemin@whu.edu.cn.

Funding

Wuhan University Health Science Center Teaching & Research Project Research on the Application of Outcome-Based Education (OBE) Combined with Case-Based Collaborative Learning (CBCL) in Clinical Stomatology Practice: A Research Study Project No. 2024YB45
6 · The paper itself

Abstract

backgroundDentin microcracks following root canal treatment may progress to vertical root fractures, a severe clinical complication. Engine-driven nickel-titanium (NiTi) instruments are associated with dentin microcrack initiation, but current evidence remains inconsistent. This review systematically synthesizes micro-CT-derived evidence on the effects of different NiTi instrument systems on dentin microcrack formation.

methodsA systematic search of PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, and grey literature was performed from inception to October 1, 2025. Eligible studies were ex vivo investigations comparing dentinal microcrack incidence after root canal preparation with various NiTi instruments. Two reviewers independently conducted study selection, data extraction, and risk-of-bias assessment using adapted JBI and CRIS checklists; meta-analysis was performed for sufficient comparable data.

resultsTwenty-four ex vivo studies were included from 256 initially retrieved records, covering all tested NiTi instrument subgroups with a pooled total sample of 1082 extracted mandibular and maxillary teeth. Studies testing instruments including RECIPROC, WaveOne, ProTaper Next, the HyFlex series, and TRUShape reported a 0% microcrack incidence under specific experimental conditions. Meta-analysis revealed the following findings: (1) Thermally treated instruments had significantly lower microcrack incidence than conventional ones (pooled incidence: 1% vs. 9%, p = 0.0046); (2) ProTaper Gold had significantly lower microcrack incidence than ProTaper Universal (pooled incidence: 3% vs. 16%, p = 0.0403); (3) ProTaper Universal had higher microcrack incidence in moderately to severely curved canals (20°-40°) (30%) than mildly curved canals (< 20°) (11%), though the difference was not statistically significant (p = 0.2230); (4) There was no significant difference in microcrack incidence between reciprocating and rotary instruments (p = 0.2095); (5) No significant difference in microcrack incidence between RECIPROC Blue and WaveOne Gold, both reciprocating systems (p = 0.3978); (6) WaveOne Gold did not differ significantly from conventional WaveOne (p = 0.6813), nor did RECIPROC Blue from conventional RECIPROC (p = 0.5334); (7) XP-endo instruments consistently demonstrated an almost 0% microcrack incidence across studies. They may effectively prevent dentinal microcracks even in moderately to severely curved canals. Funnel plot showed good symmetry, indicating no significant publication bias.

conclusionWithin the limitations of this ex vivo meta-analysis, instrument kinematics did not influence microcrack formation, while thermally treated NiTi instruments significantly reduced risk. Thermally treated systems are preferred, and highly flexible, advanced-design instruments should be prioritized for curved canals to minimize dentin microcracks.

Indexed as

Dental InstrumentsDentinNickelRoot Canal PreparationTitaniumTooth FracturesHumansX-Ray MicrotomographyNickelTitaniumtitanium nickelideDentin microcracksMeta-analysisMicro-CTNickel-titanium instrumentsRoot canal preparationSystematic review

Identifiers

PMID42897518
PMCPMC13681857

What OpenQuestion holds

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Registered trials

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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.