11mm Overjet Corrected with Invisalign — No Headgear, No Herbst

Presentation

Chief complaint. " I want to fix my bite with Invisalign. I don't want braces."

Diagnosis. Six-year-old female presents with a significant Class II skeletal and dental malocclusion characterized by a markedly convex facial profile and a severely retrognathic mandible. Clinical findings include: Approximately 11 mm overjet Full-cusp Class II molar relationship Approximately 2 mm overbite Severely constricted maxillary arch Maxillary and mandibular spacing Proclined maxillary and mandibular incisors History of ankyloglossia/tongue-tie at birth History of anterior dental trauma, with bonding restorations along the incisal edges of the maxillary anterior teeth following previous fractures Because of the pronounced incisor protrusion and excessive overjet, the patient is at increased risk for additional trauma to the maxillary anterior teeth. Overall, she presents with a skeletal Class II pattern primarily related to mandibular retrognathia, significant excessive overjet, transverse maxillary constriction, and proclined incisors, with a history of anterior dental trauma that increases the importance of early risk reduction.

Measurements

Cephalometric values before and after treatment
Measure	Norm	Pre	Post
SNA	82	81	80
SNB	80	72	75
ANB	2	8	5
Wits	0	7	1
SN-MP	32	29	32
U1-SN	102	117	97
L1-MP	90	102	102
Overjet (mm)	2–3	11	2
Overbite (mm)	2–3	1	1

Treatment

Objectives. Use Invisalign First with Class II elastics in a functional, Twin Block–like approach to posture the mandible forward and encourage a more favorable maxillomandibular relationship during growth. Improve the severe mandibular retrognathia and skeletal Class II relationship by taking advantage of the patient's remaining facial growth. Expand and develop the constricted maxillary arch with the upper aligners to improve transverse width and establish a broader, more appropriate arch form. Retract and upright the protrusive maxillary incisors to significantly reduce the 11 mm overjet and dental protrusion. Reduce the prominence of the maxillary anterior teeth and thereby decrease the risk of recurrent dental trauma. Improve the full-cusp Class II relationship toward Class I through a combination of growth modification and dentoalveolar correction. Coordinate the upper and lower arches while maintaining appropriate space for eruption of the developing permanent dentition. Establish a more normal overjet and overbite and improve overall facial and dental balance. Monitor mandibular growth and facial development as the patient continues to grow.

Plan. Begin Phase I treatment with Invisalign First to develop and coordinate the upper and lower arches while taking advantage of the patient's remaining growth. Expand the maxillary arch, including the primary dentition, to correct the significant transverse constriction and develop a broader, more appropriate arch form. Develop and coordinate the lower arch through the primary dentition as needed. Perform only limited distalization of approximately 1–1.5 mm, avoiding excessive dental compensation at this young age. Use Class II elastics with the aligners to encourage forward mandibular positioning and improve the Class II relationship while the patient is actively growing. Allow continued mandibular growth to contribute to the remainder of the Class II correction, rather than attempting to correct the entire discrepancy through tooth movement. Reduce the excessive 11 mm overjet by improving the jaw relationship and retracting/uprighting the protrusive maxillary incisors, thereby decreasing the risk of additional anterior dental trauma. Close the anterior spacing and improve incisor alignment. Create and preserve adequate space for eruption of the permanent canines and developing permanent dentition. Monitor mandibular growth, eruption, overjet, and the developing occlusion throughout Phase I treatment. The goal is to achieve early transverse correction, reduce the traumatic overjet, improve the Class II relationship, and establish adequate space for eruption, while preserving future treatment options as the patient continues to grow.

Appliances and materials

Invisalign First
Class II elastics — 3/8 heavy worn 22 hours a day

Progress records

Superimpositions

Upper incisors retracted and we got substantial mandibular growth in one year

Outcome

The patient demonstrated excellent compliance at six years of age, wearing her aligners consistently and changing her Class II elastics approximately three times per day. Over the course of approximately 12 months, we achieved: Significant maxillary arch expansion Improved development and coordination of both the upper and lower arches Substantial improvement in the Class II jaw relationship Marked forward positioning of the mandible during growth Reduction of the initial 11 mm overjet to a substantially improved positive overjet Improved anterior tooth position, reducing the prominence and traumatic risk of the maxillary incisors Improved space and arch form for the developing permanent dentition Duration: 12 months,# of Aligners: 34 , # of Visits: 7, Aligner change: 7 days The degree of correction was remarkable, particularly given the severity of the initial mandibular retrognathia and overjet. This case became an important part of our clinical approach to growing Class II Division 1 patients. In appropriately selected and compliant children, we have since used a similar protocol combining Invisalign First, arch development, limited dental distalization, and Class II elastics to take advantage of growth while correcting the bite. For our practice, this has become a preferred early-treatment approach in many Class II Division 1 cases and can reduce the need for more traditional appliances such as Herbst appliances or headgear in selected patients.

Retention

Essix retainers with palatal coverage to be worn full time for 6 months then nighttime only

Upper Essix with palatal coverage and lower Essix retainers