1. Crowded dentition with misaligned teeth, such as canine teeth (eye‑teeth).
2. 下Severe crowding of lower anterior teeth, where extra space for alignment can only be obtained by tooth extraction.
3. Some patients present with protruding teeth and flared lips. Tooth extraction creates space for retracting anterior teeth and improves the profile of protruding lips.
4. For patients with mild crowding and slight arch protrusion yet poor posterior‑teeth occlusion, low chewing efficiency and potential risk of temporomandibular joint injury in front of the ear, extraction‑assisted orthodontic treatment may also be considered.
Advantages of Invisible Orthodontics
1. Convenience: Aligners can be removed at will for eating, drinking, tooth‑brushing and special social occasions.
2. Aesthetic effect: The aligners are nearly invisible.
3. Comfort: No metal brackets or arch‑wires to irritate the gingiva and oral mucosa.
4. Precision: Designed with computer‑aided three‑dimensional modelling based on individual dental models.
Note: The decision for tooth extraction requires comprehensive evaluation including X‑ray examination, dental impressions and facial profile analysis. Not all above‑mentioned cases definitely need tooth extraction.
