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Updated: Jun 16, 2026
07:32
Measuring Maxillary Posterior Tooth Movement: A Model Assessment using Palatal and Dental Superimposition
Published on: February 23, 2024
Longitudinal changes in mandibular arch posterior space in adolescents with normal occlusion
Li-Li Chen1, Tian-Min Xu, Jiu-Hui Jiang
1Orthodontics Department, Peking University, Beijing, China.
Summary
Available mandibular space in teenagers increases significantly with age and differs between sexes. This growth is primarily due to bone resorption before third molar eruption.
Area of Science:
- Orthodontics
- Craniofacial development
- Dental anthropology
Background:
- Understanding mandibular growth is crucial for orthodontic treatment planning.
- Adolescent dental arch development involves complex spatial changes.
- Limited data exists on longitudinal changes in available mandibular space.
Purpose of the Study:
- To investigate changes in available mandibular space in the posterior dental arch.
- To analyze these changes in adolescents aged 13 to 18 years.
- To identify age and sex-related differences in mandibular arch space.
Main Methods:
- Longitudinal cephalometric analysis of 28 adolescents (13 boys, 15 girls) with normal occlusion.
- Annual radiographic assessments from age 13 to 18.
- Modified analyses using occlusal plane and its perpendicular as reference planes.
Main Results:
- Significant age and sex differences in posterior mandibular space were observed.
- Total space increase was 5.12 mm for girls and 5.79 mm for boys.
- Bone resorption at the anterior ramus border primarily contributed to space increase before age 16 (girls) and 17 (boys).
- Mesial drift of the dental arch occurred with third molar eruption.
Conclusions:
- Available mandibular space prediction requires consideration of both age and sex.
- Growth patterns vary, necessitating individualized orthodontic approaches.
- Understanding these developmental changes aids in predicting orthodontic outcomes.
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