Molar Distalization By Tads In Severe Crowding With Clear Aligners

Severe dental crowding was treated through maxillary and mandibular molar distalization by TADs with clear aligners. Patient : Ruan X, female, 26 years old, complained of dental crowding for many years.Clinical examination : A.straight face type and the face is basically symmetrical.B.a.Permanent dentition, no obvious caries in the mouth. b.Bilateral canine and molar distal relationship .Severe crowding of upper and lower arch. Anterior deep overbite.Diagnosis: Angle Class II malocclusion with skeletal Class I, severe crowding of upper and lower arch.Active treatment (T1): miniscrews were implanted on the buccal side between U6/U7,and buttons were bonded between the maxillary and mandibular canines. Intermaxillary traction was applied to assist the maxillary and mandibular molar distalization. Refinement(T2):coordinate the upper and lower arch, intrude the upper and lower anterior teeth, improve the deep overbite, and establish the normal occlusion relationship.Retention (T3): Hawley retainer and long time followups. Outcomes:A.Maxilla:U6 achieved 3.45mm(115% efficiency)0.11mm/month velocity, 1.35mm intrusion, 2°distal tipping.B.Mandible:L6 showed 2.34mm(63% efficiency)0.075mm/month velocity, 0.51mm intrusion, 3° distal tipping.C.Torque control:U1-SN reduced by 3.82°, L1-MP proclined 1.68°. severe crowding can be treated by maxillary and mandibular molar distalization by TADs with clear aligners in the straight profile case. Clear aligners with TADs can effectively treat severe crowding non-extractively (>85% distalization efficiency) with improved incisor torque and profile control.