Tooth extraction has no adverse effect on oral function, but often improves and enhances oral function.

The principle of tooth extraction before orthodontics is:

1, try not to extract teeth or extract teeth less.

2. Try to remove the diseased teeth that can't be preserved and the teeth that don't affect the function.

3. Tooth extraction cannot shorten the course of treatment or simplify the treatment.

4, tooth extraction treatment should be able to improve occlusion, enhance function and beauty.