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. 2025 Apr 25;29(5):274.
doi: 10.1007/s00784-025-06351-z.

Effect of clear aligners on distalization of maxillary first molars in mixed dentition and early permanent dentition: a retrospective study

Yue Li  1   2 , Meiying Wu  1   2 , Xinyu Xing  1   2 , Yumiao Chen  1   2 , Chengle Zhang  1   2 , Junhan Hu  1   2 , Congchong Shi  3   4
Affiliations

Effect of clear aligners on distalization of maxillary first molars in mixed dentition and early permanent dentition: a retrospective study

Yue Li et al. Clin Oral Investig. .

Abstract

Background: The differential impact of maxillary first molar distalization on the three-dimensional displacement of the maxillary second molars during crown formation (Nolla 4-6 stages) and root development (Nolla 7-8 stages) remains unclear. Furthermore, the influence of two stages on the three-dimensional displacement of the first molars and central incisors, as well as the actual distal displacement and displacement rate of the first molars requires further investigation.

Method: 36 patients were equally divided into Nolla 4-6 stages group ( aged 8.50 ± 0.92 years) and Nolla 7-8 stages group ( aged 11.27 ± 0.67 years). CBCT data were analyzed before and after distalization. Normally distributed data were analyzed using paired sample T-tests, with significance set at P < 0.05.

Result: (1) After distalization in Nolla 4-6 and Nolla 7-8 stages groups, the first and second molars showed buccal movement, distobuccal rotation and crown distal inclination (P < 0.05). Proclination of the maxillary central incisors was found. (2) Compared to Nolla 4-6 stages group, the degree of distobuccal rotation and crown distal inclination of second molars, distobuccal rotation of first molars and proclination of central incisors were smaller and the realization rate was larger in Nolla 7-8 stages group (P < 0.05).

Conclusions: Clear aligners can effectively distalize maxillary first molars when second molars are unerupted. However, the movement of molars and central incisor, the actual displacement and realization rate of first molars are different in Nolla 4-6 and Nolla 7-8 stages. Treatment plans should be tailored to the developmental stage of the second molars to enhance efficiency and ensure optimal dental and maxillofacial health in children.

Keywords: Angle Class II malocclusion; Clear aligner treatment; Early orthodontic treatment; Early permanent dentition; Maxillary first molar distalization; Mixed dentition.

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Conflict of interest statement

Declarations. Ethical approval: This study has been approved by the Medical Ethics Committee of the Affiliated Stomatology Hospital of Kunming Medical University, and the approval number is KYKQ2023MEC0115. Informed consent: All participants and their parents signed the informed consent. Competing interests: The authors declare no competing interests.

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References

    1. Ravera S, Castroflorio T, Garino F, Daher S, Cugliari G, Deregibus A (2016) Maxillary molar distalization with aligners in adult patients: a multicenter retrospective study. Prog Orthod 17:12. https://doi.org/10.1186/s40510-016-0126-0 - DOI - PubMed - PMC
    1. Caruso S, Nota A, Ehsani S, Maddalone E, Ojima K, Tecco S (2019) Impact of molar teeth distalization with clear aligners on occlusal vertical dimension: a retrospective study. BMC Oral Health 19(1):182. https://doi.org/10.1186/s12903-019-0880-8 - DOI - PubMed - PMC
    1. Pu L (2001) Effect of second molar eruption on distally moving first molar. Stomatology 04:200–201
    1. He M (2010) Biomechanical effects of different anchorage methods and different second molar eruption status on the distalization of the maxillary first molar. Dissertation, Chongqing Medical University
    1. Nolla C M (1952) The development of permanent teeth. Dissertation, University of Michigan

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