Case report
Nonextraction treatment of a skeletal Class III malocclusion

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This case report describes the nonsurgical, nonextraction therapy of a 16-year-old boy with a skeletal Class III malocclusion, a prognathic mandible, and a retrusive maxilla. He was initially classified as needing orthognathic surgery, but he and his parents wanted to avoid that. The Class III malocclusion was corrected with a rapid palatal expander and a maxillary protraction mask followed by nonextraction orthodontic treatment with fixed appliances, combined with short Class III and vertical elastics in the anterior area. The height of the maxillary alveolar process and the vertical face height were slightly increased with treatment. Class I molar and canine relationships were achieved, and the facial profile improved substantially.

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Diagnosis and etiology

The patient was a boy, aged 16 years 4 months, whose chief complaint was the anterior crossbite. He had Class III canine and molar relationships on both sides, 5-mm negative overjet, 1-mm anterior open bite, bilateral crossbite with the maxillary midline coincident to the midsagittal plane, and a 1-mm deviation of the mandibular midline to the right. Both dental arches had about 2 mm of excess space, and there was slight facial asymmetry (Fig 1, Fig 2, Fig 3). Cephalometrically, there were a

Treatment objectives

Treatment objectives included correction of the posterior and anterior crossbites, improvement of the dentoalveolar and maxillomandibular relationships, improvement of facial esthetics, and establishment of a stable occlusion.

Treatment alternatives

Three treatment options were suggested to the patient and his parents. The first alternative consisted of combined surgical and orthodontic treatment with a high LeFort procedure and mandibular osteotomy to improve maxillary and facial appearance.

The second consisted of maxillary expansion and extraction of the mandibular first premolars. This would correct the Class III dental relationship, but it would also involve retraction of the mandibular incisors without protrusion of the maxillary

Treatment progress

Treatment began with placement of a banded rapid palatal expander on the maxillary first molars and premolars (Fig 5). The patient was instructed to activate the appliance .5 mm every day for 2 weeks. Subsequently, he received a facemask for maxillary protraction with a forward and downward force directed approximately 30° to 40° to the maxillary occlusal plane. The patient was instructed to wear it for 18 hours a day (Fig 6). A force of 400 g on each side was delivered by elastics attached to

Treatment results

The posttreatment extraoral photographs show general improvement in the facial profile. The posttreatment intraoral photographs and dental casts show satisfactory dental alignment, Class I canine and molar relationships on both sides, and normal overjet, overbite, and transverse relationships (Fig 8, Fig 9). There was significant improvement in the maxillomandibular relationship as cephalometrically shown by changes in the ANB angle, Wits appraisal, and overjet. The maxillary arch moved

Discussion

The treatment objectives were attained with the nonextraction treatment protocol. Usually, use of a facemask to correct Class III malocclusions through maxillary protraction is indicated in the deciduous and mixed dentitions.9 Little maxillary protraction is expected when it is used in the permanent dentition.1 However, there might be some exceptions in compliant patients, when clinically significant maxillary advancement can be obtained, as in this patient. Because there was a 9.8-mm increase

Conclusions

Successful occlusal and esthetic correction of a Class III malocclusion in the permanent dentition can be accomplished with a protraction facemask and Class III intermaxillary elastics when the patient's compliance in using the elastics is satisfactory. Once the correction is successful, active retention and follow-up are essential if the patient is still growing.

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