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Long-term stability of Class I premolar extraction treatment
Jimmy C Boley1, Jeffrey A Mark, Rohit C L Sachdeva
1Department of Orthodontics, Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX 75243, USA.
Summary
This study on Class I orthodontic patients treated with premolar extraction shows that most achieve satisfactory long-term mandibular incisor alignment. Careful treatment planning is key for stable results after retention.
Area of Science:
- Orthodontics
- Dental Arch Stability
- Tooth Movement Analysis
Background:
- Class I malocclusions often require premolar extraction for optimal alignment.
- Long-term stability of orthodontic treatment outcomes is a significant clinical concern.
- Understanding post-retention changes is crucial for evidence-based treatment planning.
Purpose of the Study:
- To evaluate the long-term stability of Class I patients treated with four premolar extractions.
- To assess post-retention changes in mandibular incisor alignment and arch dimensions.
- To identify factors contributing to successful long-term orthodontic outcomes.
Main Methods:
- Retrospective analysis of 32 Class I patients treated with the edgewise appliance and Tweed philosophy.
- Minimum 5 years out of retention, with examinations averaging 15 years post-treatment.
- Cephalometric and model analyses to evaluate pre- and post-treatment tooth movements and arch dimensions.
Main Results:
- Mandibular incisor irregularity increased slightly (0.7 mm) post-retention, with 80% maintaining satisfactory alignment (<3.5 mm) over 10 years.
- Mandibular intercanine width increased during treatment but decreased post-retention (-1.4 mm).
- Arch length decreased during treatment and continued to decrease post-retention (-1.4 mm) due to mesial molar movement.
Conclusions:
- Satisfactory long-term results are achievable for Class I, four-premolar-extraction patients.
- Evidence-based treatment objectives, including minimal mandibular arch form alteration and controlled incisor positioning, are vital.
- Maintaining mandibular incisor position and uprighting are key to long-term stability.