Management of skeletal Class III malocclusion with reverse pull headgear in a growing individual

INTRODUCTION

Class III malocclusion is one of the most difficult problems to treat in the mixed dentition, often resulting in bilateral anterior and posterior cross-bites.^[1] This malocclusion is most likely to be associated with a variety of environmental and genetic factors.^[2,3] Prevalence of skeletal Class III malocclusion is greater among the Asian population as compared to Caucasians.^[4] If left untreated, the skeletal discrepancy gets worse with time.

The dental and skeletal effects of maxillary protraction with a facemask during the mixed dentition phase have not been well documented in the literature. These cases are generally left untreated during the mixed dentition phase because of poor patient cooperation, leading to an increased skeletal discrepancy with time. Orthopedic therapy in the late-mixed or early permanent dentition can be successful, but the results are generally better when carried out in the deciduous or early-mixed dentition.^[5,6] In this case-report, we describe clinical presentation, dental examination, radiological investigations, treatment plan, and outcomes of a 12-year-old female child with skeletal Class III malocclusion due to a retrognathic maxilla, seeking orthodontic treatment at a private orthodontic clinic.

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Figure 1

Pretreatment extraoral and intraoral pictures

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Figure 2

Pretreatment orthopantomogram radiograph

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Figure 3

Pretreatment cephalogram radiograph

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Figure 4

Reverse pull headgear

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Figure 5

Posttreatment extra- and intra-oral pictures

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Figure 6

Posttreatment cephalogram radiograph

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CASE REPORT

A 12-year-old female patient reported to the orthodontic clinic, with a presenting complaint of a protruded lower jaw and irregular placement of the front teeth. The patient did not have any other dental complaint or prior history of seeking dental care. The patient did not have any known comorbidity or genetic disorder or syndrome. There was no significant medical or surgical history and was not taking any medication at the time of presentation. Extraoral examination revealed a leptoprosopic face form with a concave profile and an obtuse nasolabial angle. The patient had a minimal smile line with decreased incisal visibility. Intraoral examination showed a Class III molar and canine relationship, bilateral anterior and posterior cross-bites along with a reverse overjet of 4 mm. Deciduous second molars were present bilaterally in the lower arch and unilaterally on the left side in the upper arch. No other significant abnormalities were observed during intraoral examination [Figure 1]. An orthopantogram and lateral cephalogram were carried out as part of routine radiological investigations. The orthopantomogram confirmed the presence of deciduous teeth and their permanent successors [Figure 2]. Cephalometric evaluation revealed an SNA of 70° and an SNB of 81°, indicating that the patient had a skeletal Class III malocclusion because of a retrognathic maxilla with an ANB of −11°. The upper incisors had normal inclination, indicated by a UISN angle of 99° while the lower incisors were retroclined according to the IMPA value of 72° [Table 1 and Figure 3]. Based on the extraoral/intraoral findings and the radiographic investigations carried out, a comprehensive and detailed treatment plan was made. The initial treatment plan involved fixed orthodontic appliance therapy. A few weeks after that, a reverse pull headgear was included in the treatment plan to achieve the ideal orthopedic effect required for the correction of skeletal discrepancy. The reverse pull headgear was attached to two hooks incorporated in the anterior region of the maxillary dentition. The approximate duration of wear for the reverse pull gear was 14–15 h as reported by the patient [Figure 4]. During this treatment phase, the patient was advised to wear Class III elastics for better results. The treatment continued for 3 years and led to improved facial esthetics [Figure 5]. The posttreatment cephalometric evaluation revealed an SNA of 79° and an SNB of 78°, indicating that the patient’s malocclusion was primarily corrected by maxillary protraction and clockwise rotation of the mandible, correcting the ANB from −11° to +1°. An increase in the values of SNMP from 31° to 38° and FHMP from 20° to 26° confirmed the clockwise rotation of the mandible [Figure 6]. At the end of treatment, well-aligned dental arches with a positive overjet and a Class I molar and canine relationship were achieved [Figures 5 and 7].

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Figure 7

Posttreatment orthopantomogram radiograph

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DISCUSSION

During orthopedic treatment, an attempt is made to change the morphology of craniofacial skeleton to correct the skeletal discrepancy. The reverse pull headgear provides a direct anterior force leading to downward and forward displacement of the maxilla.^[7] This orthopedic effect allows the mandible to rotate downward and backward, increasing the lower facial height and acting as a major contributing factor in establishing a positive overjet. This is accompanied by an increase in the upper incisor inclination and a decrease in the lower incisor inclination aiding in the anterior cross-bite correction.^[8] According to a study by Williams et al., the average anterior movement of point A after the orthopedic treatment was 1.54 mm and that of maxillary teeth was 2.73 mm, confirming that the positive overjet obtained was due to both skeletal and dental effects.^[9] Orthodontic fixed appliance therapy in combination with a reverse pull headgear for the correction of Class III malocclusion is believed to be more effective in early-mixed dentition as compared to late-mixed dentition.^[10] Hence, the orthopedic correction of skeletal Class III malocclusion with the help of a reverse pull headgear in a growing patient is crucial as it aids in achieving a better esthetic profile and reduces the chances of further surgical treatment to correct the skeletal discrepancy.

CONCLUSION

Skeletal Class III malocclusions due to a retrognathic maxilla in a growing individual can be successfully treated using fixed orthodontic appliances in combination with a reverse pull headgear to achieve the desired orthopedic effect. Careful case selection, patient cooperation, and long-term stabilization ensure ideal treatment results and stability. This treatment protocol is believed to be more effective in the early-mixed dentition as compared to late-mixed dentition and reduces the chances of further surgical treatment to correct the skeletal discrepancy.