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Alignment stability in Class II malocclusion treated with 2- and 4-premolar extraction protocols.
Guilherme Janson1, Mauro Carlos Agner Busato, José Fernando Castanha Henriques
1Department of Orthodontics, Bauru Dental School, University of São Paulo, São Paulo, Brazil. jansong@travelnet.com.br
Summary
Orthodontic treatment for Class II malocclusions using either 2 or 4 premolar extractions results in comparable long-term stability of mandibular anterior tooth alignment. This finding is crucial for understanding treatment outcomes in orthodontics.
Area of Science:
- Orthodontics
- Dental Research
- Craniofacial Development
Background:
- Class II malocclusions present challenges in orthodontic treatment, particularly regarding mandibular anterior tooth alignment.
- Premolar extraction is a common strategy for correcting severe malocclusions, but the impact of the number of extracted teeth on long-term stability requires investigation.
Purpose of the Study:
- To compare the postretention stability of corrected mandibular anterior tooth irregularity in Class II malocclusion patients.
- To evaluate whether extracting 2 or 4 premolars influences the long-term stability of orthodontic correction.
Main Methods:
- Sixty-six patients with Class II malocclusions were divided into two groups: 2 premolar extraction (n=19) and 4 premolar extraction (n=47).
- Little's irregularity index assessed anterior tooth irregularity on dental casts pre-treatment, post-treatment, and 5 years post-treatment.
- Statistical analysis, including t-tests, compared irregularity indices and cephalometric variables between groups.
Main Results:
- No statistically significant differences in postretention anterior tooth irregularity were observed between the 2-premolar extraction group and the 4-premolar extraction group.
- A subgroup analysis comparing patients with similar initial irregularity also showed no significant difference in stability.
Conclusions:
- Extraction of either 2 maxillary premolars or 4 premolars yields similar long-term stability for mandibular anterior tooth alignment in Class II malocclusions.
- The number of premolars extracted does not appear to be a critical factor in the postretention stability of orthodontic correction for this patient group.