Class III underbite with 2 impacted canines

Measurements

Cephalometric values before and after treatment
Measure	Norm	Pre	Post
SNA	82	79	79
SNB	80	78	77
ANB	2	1	2
Wits	0	-4	0
SN-MP	32	36	37
U1-SN	102	91	106
L1-MP	90	78	83
Overjet (mm)	2–3	-2	1
Overbite (mm)	2–3	2	1

Treatment

Objectives. Expand the maxilla and encourage maxillary advancement. Create adequate space for the impacted canines while protecting the lateral incisor roots. Retract the maxillary lateral incisors lingually to move them away from the canine eruption path, then apply distal and posterior traction to guide the canines into position. Procline the maxillary anterior teeth to correct the anterior crossbite. Level and align both arches, establish a Class I occlusion, and closely monitor future Class III growth.

Plan. Begin with a maxillary palatal expander and facemask therapy to correct the transverse deficiency and anterior crossbite. Use facemask hooks to assist with traction of the impacted canines. Initially, tie the maxillary lateral incisors to move them lingually and away from the canine roots, creating a safer eruption path. Once adequate clearance is achieved, begin distal traction of the impacted canines using the facemask hooks. Then band and bond from 7–7, open adequate space for the canines, and guide them into the arch. Continue Class III elastics as needed to maintain sagittal correction and establish a positive overjet.

Appliances and materials

Rapid Palatal Expander with face mask hooks
Reverse Pull Headgear
Metal Braces — 022 MBT
Class III elastics

Progress records

Cone Beam — Both canines are buccal and tooth #6s is mesial and buccal to #7 and #11 is also buccal

Outcome

Both canines were brought into the arch, a positive overjet was achieved, and Class III growth is being monitored.

Retention

Fixed U2-2 permanent retainer
Fixed L3-3 permanent retainer
Invisalign Vivera retainers to be worn at night

Both impacted canines were successfully brought into the arch, and a positive overjet was achieved. Both arches were leveled and aligned, crowding was resolved, anterior tooth inclinations were improved, and the midlines were coordinated. Third-molar extraction will be recommended. Because continued mandibular growth is evident, we will closely monitor the developing Class III pattern and support the correction with Class III elastics worn with the retainers as needed.