Evidence map›Paper›PMID 40481966›Full record

ArticleClinical oral investigations2025

Predictability of curve of Spee levelling and vertical tooth movements in the lower arch with clear aligners based on cone-beam computed tomography.

Shangyou Wen, Xiaoyue Han, Xian He, Qi Fan, Xuechun Yuan, Wenli Lai, Hu Long

Abstract read
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In one paragraph

Article in Clinical oral investigations, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed, 1 pooled it
–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

3 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. [Advancements in biomechanics and orthodontic strategies for clear aligner therapy].Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology · 2026
    Pooled it
  2. [Research advances in clear aligner].Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology · 2026
    Review
  3. Article
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

7 authors.

Shangyou WenDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
Xiaoyue HanDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
Xian HeDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
Qi FanDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
Xuechun YuanDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
Wenli LaiDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
Hu LongDepartment of Orthodontics, State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China. hlong@scu.edu.cn.

Funding

China Oral Health Foundation 24H0016International Orthodontics Foundation 2022 Elite Grants Award IOF-E1National Natural Science Foundation of China 82071147
6 · The paper itself

Abstract

objectiveThis study aims to evaluate the predictability of Curve of Spee (COS) levelling and vertical tooth movements (VTMs) -- anterior intrusion and posterior extrusion– to determine optimal overtreatment ratios with clear aligners.

methodsThis study included 464 teeth from 50 patients (mean age 24.3 ± 8.0; 68% female, 32% male) receiving clear aligner treatment. Pretreatment and posttreatment CBCT were superimposed with their corresponding dentition models using Geomagic Control X. The effectiveness of COS levelling and the achieved and predicted VTMs were measured.

resultsThe mean effectiveness for COS levelling was 52.9 ± 0.3%. The median effectiveness for VTMs ranged from 36.7% for mandibular first molar extrusion to 49.4% for mandibular premolar extrusion. No significant differences were observed across different tooth types (P > 0.05). The achieved changes in COS and VTM were significantly correlated with the predicted values (P < 0.001). Multivariate analysis revealed that predicted change in COS and VTM, age, pretreatment IMPA, MP-FH, COS depth, overbite, anterior intrusion staging, and extraction had differential impacts on the achieved change in COS and VTMs. Calibrated predictability values were derived, and the overtreatment ratios of 61%, 58%, 204%, and 79% were suggested for incisors, canines, premolars, and first molars, respectively.

conclusionsComplete levelling of the COS in the lower arch is not fully achievable with clear aligners. The extent of COS levelling and VTMs is significantly correlated with predicted values, IMPA, MP-FH, intrusion staging, age, and overbite. Clinicians were recommended to overtreat incisors, canines, premolars, and first molars in the setup to achieve effective COS levelling. CLINICAL RELEVANCE: Clear aligners exhibited suboptimal effectiveness in COS levelling. For effective levelling of the COS, a hybrid approach of incorporating attachments, vertical elastics, and aligners overtreatment is recommended.

Indexed as

Cone-Beam Computed TomographyOrthodontic Appliances, RemovableTooth Movement TechniquesFemaleHumansMaleMandibleClear aligner predictabilityCurve of Spee levellingExtrusionIntrusionOvertreatment

Identifiers

PMID40481966

What OpenQuestion holds

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Registered trials

None linked

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.