This case report presents the treatment of a young man with a skeletal Class III malocclusion. He was treated with a conventional surgical-orthodontic approach in which 2 jaw surgeries were performed. The esthetic facial profile, pleasant smile, appropriate occlusion, and overall good treatment outcome remained stable 10 years after active orthodontic treatment.
Highlights
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A 19-year-old man had a skeletal Class III malocclusion.
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Conventional surgical-orthodontic approach included 2 jaw surgeries.
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Good outcomes remained stable 10 years after active orthodontic treatment.
Although various types of skeletal and dental profiles are associated with Class III malocclusions, the mandible is typically the aberrant skeletal component of the patient’s craniofacial anomaly. The standard approach for adults with dentofacial deformities is surgical-orthodontic treatment. Most dentofacial deformities requiring 2 jaw surgeries can be corrected with conventional orthognathic treatment. However, currently, some clinicians are again advocating surgery first to reduce treatment time and prevent worsening of the profile during decompensation.
Proper evaluation of patients requires examination of facial soft and hard tissues. When planning surgery for Class III patients, the lip position is an important point to consider. Many factors are involved in lip protrusion, and the amount of protrusion can be controlled by various orthodontic and surgical procedures. After treatment, orthognathic surgery patients benefit from an improved smile, more positive esthetics, increased self-esteem, and consequently a better quality of life.
Orthodontists and surgeons should be experienced, and teamwork is necessary to achieve the treatment objectives. The successful attainment of treatment goals was achieved for this patient with an interdisciplinary approach.
This article describes the treatment of a Class III patient including the combination of 2 jaw surgeries. Bilateral sagittal split osteotomy procedures were performed to set back the mandible and correct the occlusal cant; a LeFort I osteotomy was performed for advancement and anterior inferior repositioning to correct the maxillary anterior vertical tooth display, the smile anatomy, and the fullness of the upper lip. The esthetics and occlusal results achieved and their stability are shown in a 10-year follow-up. See Supplemental Materials for a short video presentation about this study.
Diagnosis and etiology
A male patient, aged 19 years, came for orthodontic treatment at the dental school in Associação Brasileira de Odontologia, Porto Alegre, Rio Grande do Sul, in Brazil with the chief complaint of the unesthetic appearance of his teeth. He also complained of chewing difficulties and impaired nasal function. He reported that he had undergone orthodontic treatment when both maxillary first premolars were extracted because of lack of space for the canines. The facial photographs showed an increased lower facial third, a concave profile, and incompetent lips in a relaxed position. The upper lip was retruded by 1.5 mm, and the lower lip was protruded by 5 mm in relation to the S-line. The intraoral photographs and dental casts showed Class II molar and Class III canine relationships, 3.5-mm negative overjet, 1-mm overbite, and occlusal cant. The maxillary arch was relatively constricted, and a midline diastema could be seen. Posterior and anterior crossbites, extending from the right first molar to the left second molar, were associated with the transverse maxillary deficiency ( Figs 1 and 2 ).
The cephalometric analysis showed a Class III jaw-base relationship (ANB angle, −1°; Wits appraisal, −7 mm). The maxillary incisors were relatively well positioned, whereas the mandibular incisors were protruded (1: NA, 6 mm and 19°; 1: NB, 10 mm and 32°; IMPA, 90°). The Steiner (SNA angle, 86°; SNB angle, 85°) and McNamara analyses showed both maxillary and mandibular protrusion in relation to the cranial base (Co-A, 102 mm; A-NPerp, 5 mm; Co-Gn, 145 mm; Pog-Nperp, 11 mm). A remarkable maxillomandibular discrepancy was noticed, with Co-A to Co-Gn of 43 mm, when the normal range is 30 to 33 mm. The measurements also highlighted an increased lower facial height (82 mm). The panoramic radiograph showed all teeth, except for the third molars and maxillary first premolars ( Fig 3 ; Table ).
| Measurement | Norm | Pretreatment | Posttreatment | 10-year follow-up |
|---|---|---|---|---|
| SNA (°) | 82 | 86 | 84 | 84 |
| SNB (°) | 80 | 85 | 80 | 81 |
| ANB (°) | 2 | −1 | 4 | 3 |
| 1-NA (mm) | 4 | 6 | 4 | 6 |
| 1:NA (°) | 22 | 19 | 18 | 22 |
| 1-NB (mm) | 4 | 10 | 7 | 7 |
| 1:NB (°) | 25 | 32 | 26 | 30 |
| 1:1 (°) | 131 | 129 | 133 | 126 |
| Occl:SN (°) | 14 | 15 | 13 | 13 |
| GoGn.SN (°) | 32 | 33 | 37 | 33 |
| S-LS (mm) | 0 | −1.5 | 0 | −1 |
| S-LI (mm) | 0 | 5 | 3 | 2 |
| y-axis to FH (°) | 59.4 | 59 | 60 | 60 |
| NPog.FH (°) | 87.8 | 94 | 92 | 91 |
| Angle of convexity (°) | 0 | −1 | 4 | 2 |
| Wits (mm) | −1.17 | −7 | 1 | 1 |
| FMA (°) | 25 | 28 | 30 | 29 |
| FMIA (°) | 65 | 62 | 63 | 58 |
| IMPA (°) | 90 | 90 | 87 | 92 |
| Nasolabial angle (°) | 102 | 109 | 110 | 110 |
| A-NPerp (mm) | −1 | 5 | 4 | 2 |
| Co-A (mm) | 102 | 104 | 104 | |
| Co-Gn (mm) | 145 | 138 | 138 | |
| ALFH (mm) | 82 | 81 | 81 | |
| Pog -NPerp (mm) | −2.2 | 11 | 4 | 3 |
Treatment alternatives
The following alternatives were presented to the patient and his parents.
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Maxillary expansion followed by maxillary protraction with a facemask. Little or no orthopedic maxillary response could be expected because the patient was already 19 years old. In addition, his strong mandible required reduction to improve his profile.
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Surgically assisted rapid maxillary expansion followed by maxillary protraction with a facemask. The Steiner SNA and McNamara analyses showed maxillary protrusion in relation to the cranial base at pretreatment; therefore, this approach would worsen the profile. Moreover, the patient did not want 2 separate surgeries for surgically assisted rapid maxillary expansion and mandibular setback.
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Surgery first. This was not common 10 years ago, when this patient came to our clinic; also, studies suggested that it was less stable than conventional orthognathic surgery for mandibular prognathism.
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Conventional surgical-orthodontic approach. Double-jaw surgeries would combine bilateral sagittal spilt osteotomy to set back the mandible with LeFort I osteotomy for advancement and inferior repositioning of the maxilla.
Treatment progress
Before orthodontic treatment, the patient was referred to an oral surgeon (J.J.C.F.) for a clinical examination. Based on the diagnostic data and according to the patient’s and parent’s decision, the fourth treatment plan was chosen.
Before orthognathic surgery, the maxillomandibular tooth axes were improved during preoperative orthodontics by fixed edgewise appliances with 0.022 × 0.028-in slot brackets in both arches ( Fig 4 ). In the maxillary arch, a typical sequence of archwires, starting with 0.0175-in coaxial, followed by 0.014-in, 0.016-in, 0.018-in, 0.020-in, and 0.019 × 0.025-in stainless steel archwires (3M Unitek, Monrovia, Calif), was used. The mandibular arch followed the same sequence of archwires to eliminate crowding and provide alignment and leveling. The anterior maxillary diastema was closed with 0.019 × 0.025-in stainless steel archwires with sliding mechanics.
