Roberto Herndndez-Orsini, DMD, MPH, MS*. Birmingham, Ala. The patient was a 25-year-old white woman in good general health. She had a mildly convex ...
Class I open bite: A case report Roberto Herndndez-Orsini, DMD, MPH, MS* Birmingham, Ala.
The patient was a 25-year-old white woman in good general health. She had a mildly convex facial profile with a hyperdivergent facial pattern and a mildly acute nasolabial angle. She had a Class I malocclusion complicated by an anterior open bite tendency and a moderate lip incompetence. The patient had a mild Class III molar relationship on both sides and an overjet of 3 mm (Figs. 1-4). In addition, she had mild upper and lower crowding (3 to 4 ram). The patient's chief complaint was procumbency of anterior teeth, and she thought she had "too many teeth for [her] mouth." The cephalometric evaluation showed a Class I skeletal pattern, although Class III features were present (ANB = 1.5, Wits = - 7 mm). She had a long lower facial height, a high mandibular plane angle, a 9 mm lip incompetence, and a 2 mm anterior open bite (Fig. 5).
TREATMENT PLAN The limitations of orthodontic therapy alone were explained to the patient. Stability of her malocclusion by compensating dental movement was questionable. In addition, the *FormerGraduate Student in Orthodontics, Universityof Alabama Schoolof Dentistry; now AssistantProfessor, Universityof Puerto Rico School of Dentistry, San Juan, Puerto Rico. 814116333
Table I. C u s t o m c e p h a l o m e t r i c analysis
SNA (degrees) SNB (degrees) ANB (degrees) Wits (ram) LFtt (%) i" to NA (mm) T to NA (degrees) T to PP (degrees) I to NB (mm) I to NB (degrees) Occlusal plan to SN (degrees) Mandibular plant to SN (degrees) ! to MP (degrees) 1 to A-Po (mm)
Fig. 1. A through C, Pretreatment facial views. 100
82.4 80.9 1.6 - 1.0 54.0 4.3
77.0 75.5 1.5 -7.0 62.0 10.0
81.0 78.0 3.0 0.5 61.0 5.5
22.8
31.0
23.0
112.0
115.0
1 ! 1.0
4.0
7.0
6.0
25.3
27.0
27.0
14.4
26.5
16.0
32.9
36.0
33.0
90.0
94.5
97.0
2.7
5.5
2.0
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Fig. 2. A through E, Pretreatment intraoral views.
patient further expressed her desire for an esthetic change in her appearance. Orthognathic surgery was explained to the patient, and a prediction of changes to be achieved with and without surgery were addressed in the consultation. Combined orthodontic and orthognathic surgery procedures were chosen by the patient for correction of her malocclusion. The request was made for nonextraction treatment, if possible. After the treatment consultation, the following treatment objectives were proposed: 1. Correction of the open bite by impaction of the maxilla superiorly and posteriorly.
2. Reduction of the anterior lower facial height by impaction of the maxilla to allow mandibular autorotation. 3. Decreased proclination of maxillary incisors by rotation of the anterior maxillary segment during impaction, then a decrease in the amount of anterior torque. 4. Elimination of the mild upper and lower crowding. Edgewise 0.018 × 0.025-inch appliances were used in the following sequence: i. The maxillary and mandibular arches were both
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Hernandez-Orshli
Fig. 3. A through E, Pretreatment study models.
W
i
1 ,dl Fig. 4. Pretreatment panoramic radiograph.
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5.5m
,-7==
Fig. 5. Cephalometric tracing of pretreatment lateral radiograph.
Fig. 6. Presurgical orthodontic dental movement superimposition. The maxilla was superimposed in ANS-PNS and the mandibular outlines in the symphysis and mandibular plane.
Fig. 7. A through C. Posttreatment facial views.
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