Case report
Conservative treatment for a growing patient with a severe, developing skeletal Class III malocclusion and open bite

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An 8-year-old Chinese girl sought treatment for a severe skeletal Class III malocclusion and open-bite skeletal pattern. Traditionally, patients with a skeletal Class III malocclusion are treated after they have stopped growing, and then they are treated with a combined orthodontic and orthognathic surgery approach. But the risks and expenses of this treatment plan are not acceptable to all patients. This young patient was treated with facemask therapy, a maxillary expansion device, and a molar occlusal splint for maxillary developmental stimulation with control of vertical jaw growth. After the completion of orthopedic therapy, 2 × 4 technology was used to adjust molar positions. A bonded tongue crib was used in the early permanent dentition to help the patient break her bad tongue habits. Straight-wire appliances were used for 16 months to adjust the occlusal relationship. This achieved significant improvement in anterior tooth relationships and facial profile esthetics. At the 2-year posttreatment follow-up, the results were satisfactory. The success of the sagittal relationship correction between the maxilla and the mandible for a skeletal Class III malocclusion depends on the coordination of transverse and vertical relationships combined with the growth potential of each patient.

Section snippets

Diagnosis and etiology

The patient was a girl aged 8 years with no relevant medical history of bone or dental pathology in her family, but she had bad tongue habits. The extraoral examination showed a midface deficiency along with a Class III profile (Fig 1). The intraoral examination showed a Class III malocclusion with posterior and anterior crossbites and with anterior open bite.

The dental casts (Fig 2) showed a transverse deficiency and an arch length deficiency in the maxillary arch. Moreover, molar and canine

Treatment objectives

The proposed primary treatment objectives were as follows.

  • 1.

    Stabilize the maxillary and mandibular vertical relationship.

  • 2.

    Eliminate the functional limitation of the mandible by transverse expansion of the maxillary arch in the early period.

  • 3.

    Coordinate the maxillary and mandibular sagittal relationships by correction of the dental malocclusion.

  • 4.

    Obtain a normal posterior overjet and correct the anterior open bite and anterior crowding.

Treatment alternatives

The first alternative was combined orthodontic and orthognathic surgery after the patient was an adult. In this proposal, presurgical decompensatory treatment could be used to relieve minor dental crowding. Meanwhile, a normal inclination angle of the maxillary and mandibular anterior teeth could be achieved. Through orthognathic surgery, the maxillary position could be reset to improve the midfacial concave profile. With backward and counterclockwise rotation of mandible, the open bite could

Treatment progress

Stage 1 included orthopedic therapy that lasted for 2 years 3 months. The intermaxillary locked bite had to be eliminated as a priority for the adjustment of the sagittal relationship. Therefore, a rapid maxillary expansion (RME) appliance and an occlusal splint were placed in the maxilla. An occlusal splint for the posterior teeth was used to control molar extrusion. When proper maxillary arch width was obtained after expansion, the RME appliance was still kept in place to prevent recurrence

Treatment results

A good profile was obtained (Fig 9). The maxillary development deficiency was corrected, and the clockwise rotation of the mandible under orthopedic therapy did not worsen, so that the facial growth direction was well maintained. With regard to the teeth, an Angle Class I relationship was obtained for the molars with normal anterior overbite and overjet (Fig 10). No dental root resorption and alveolar bone loss were shown in the panoramic radiograph (Fig 11).

The results of the cephalometric

Discussion

It is difficult to establish and maintain normal overbite and overjet relationships in orthodontic treatment for patients with a skeletal Class III malocclusion combined with an open bite caused by jaw growth patterns and bad tongue habits. We believe that in the early orthodontic therapy for a patient with a skeletal malocclusion, every step of the treatment should follow the biomechanism of the dentomaxillary system. Only when the physiologic compensatory mechanisms of the dentomaxillary

Conclusions

The orthodontic approach in compliance with the biomechanism of the dentomaxillary system has great success in obtaining cosmetic and stable results. As far as a teenage patient with a skeletal Class III malocclusion is concerned, the jaw growth direction must be maintained without change during treatment, while the orthopedic force is needed to adjust the sagittal jaw relationship. Changes of the balance of internal and external myodynamics are also necessary to establish a dental compensatory

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All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.

Financial support from the Project on the Integration of Industry, Education and Research of Guangdong Province (2010B080701101).

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