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Maxillary arch expansion in different dentition stages using clear aligners: a three-dimensional finite element
Runzhi Guo1, Yuanyuan Zheng2, Zining Chen1
1Department of Orthodontics, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 10008, China.
Clear aligners (CAs) show varying maxillary arch expansion efficiency based on dentition stage. Mixed dentition leads to mid-arch expansion with incisor tipping, while permanent dentition offers better posterior expansion and torque control.
Area of Science:
- Orthodontics
- Biomechanical Engineering
- Dental Development
Background:
- Clear aligners (CAs) are increasingly used for orthodontic treatment.
- Understanding the biomechanical efficiency of CAs during maxillary arch expansion across different developmental stages is crucial for effective treatment planning.
Purpose of the Study:
- To analyze the efficiency and biomechanical mechanisms of clear aligner (CA) maxillary arch expansion in various dentition developmental stages.
- To compare the dental displacement and stress distribution patterns during CA expansion in mixed and permanent dentitions.
Main Methods:
- Four 3D finite element models simulating maxillary arch expansion with CAs were created for early mixed, late mixed, early permanent, and permanent dentition stages.
- A 0.2 mm buccal expansion was simulated, and 3D tooth displacement and von Mises stress in the roots were analyzed.
Main Results:
- Late mixed dentition exhibited the greatest mid-arch expansion (0.102 mm) with buccal tipping. Early permanent dentition showed improved torque control.
- Posterior arch expansion was less pronounced; permanent dentition had smaller molar displacement, while mixed dentition showed palatal molar movement.
- Maxillary incisors proclined labially in mixed dentition and inclined lingually in permanent dentition. Highest root stress was observed in the first primary molar of early mixed dentition.
Conclusions:
- Clear aligner (CA) maxillary expansion efficacy and biomechanics vary significantly with dentition stage in adolescents.
- Mixed dentition shows primary mid-arch expansion with specific molar and incisor movements, whereas permanent dentition allows for more effective posterior expansion and torque control.
- Clinical application requires careful consideration of these stage-specific biomechanical differences, acknowledging limitations such as the exclusion of sutural maturation status.
