Full text of DOI:10.1016/S0889-5406(00)70165-X

ABO CASE REPORT
Treatment of a patient with a Class I malocclusion with
bialveolar protrusion, mild upper and lower crowding, and mild
mandibular prognathism
Roberto Hernandez Orsini, DMD, MPH, MSa
Guaynabo, Puerto Rico
This case report was presented to the American Board of Orthodontics in partial fulfillment of the requirements
for the certification process conducted by the Board. (Am J Orthod Dentofacial Orthop 2000;117:453-8)
Fig 1. Pretreatment facial photographs.
Fig 2. Pretreatment intraoral photographs.
DIAGNOSIS
The medical history was unremarkable. The
History and General Clinical Background
patient was aware of the significant lip projection
The patient, a 23-year 9-month old white woman,
was a dental assistant. Her chief goal was “to reduce
the projection of the lips.”
associated with her malocclusion. She was concerned
about her appearance and anxious to begin orthodon-
tic treatment.
The dental history revealed that the patient had lost
both mandibular first molars before the age of 10 years
as the result of large carious lesions. She had multiple
restorations. Her oral hygiene was excellent and
remained so throughout treatment. A tongue thrust
aIn private practice.
Reprint requests to: Roberto Hernandez-Orsini, Camini Alejandrino #4, Villa
Clementina, Guaynabo, Puerto Rico, 00969
Copyright © 2000 by the American Association of Orthodontists.
0889-5406/2000/$12.00 + 0 8/5/90184
doi.10.1067/mod.2000.90184
453

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American Journal of Orthodontics and Dentofacial Orthopedics
April 2000
Fig 3. Pretreatment casts.
Fig 4. Pretreatment panoramic radiograph.
habit was present. The cause of the malocclusion was
both environmental and hereditary.
Fig 5. Pretreatment cephalogram.
The patient’s face is symmetric. The facial pho-
tographs (Fig 1) illustrate protrusive upper and lower lips
and a prominent mandible. Dentally, the patient exhibits
a Class I mutilated occlusion (Fig 2). All maxillary teeth
are present, and the mandibular first molars are missing
(Figs 3 and 4). The cephalometric evaluation (Figs 5 and
6) confirms a bialveolar protrusion with proclined and
procumbent maxillary and mandibular incisors (Table I).
2. Align and level the dentition.
3. Upright the mandibular second molars for future
crown and bridge premolar size reconstruction.
4. Achieve a good functional Class II molar, Class I
canine occlusion with proper overjet and overbite.
5. Achieve a nice smile and improve the sagittal lip
projection, and maintain a good facial balance,
both vertically and horizontally.
TREATMENT OBJECTIVES
TREATMENT PLAN
1. Reduce the proclination and procumbency of the
maxillary and mandibular anterior segments to
improve esthetics, speech, and function.
The maxillary second premolars were extracted in
order to have space to retract the maxillary anterior seg-

American Journal of Orthodontics and Dentofacial Orthopedics
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Volume 115, Number 4
Fig 6. Pretreatment cephalogram tracing.
Fig 7. Posttreatment facial photographs.
ment. Uprighting of the mandibular second molars for
future prosthetic work was proposed and recommended.
A high pull headgear was to be used for proper vertical
control during treatment. Results of the mandibular sec-
ond molar uprighting were expected to be good based on
the patient’s excellent periodontal condition and oral
hygiene habits. The ability to achieve the proposed
esthetic and functional results was favorable because the
patient’s compliance was going to be excellent. Ortho-
dontic results were to be retained with maxillary and
mandibular removable retainers, replacement of the
missing mandibular first molars, and a lingual mandibu-
lar canine to canine bonded retainer.
TREATMENT PROGRESS
A high pull headgear was inserted early in treat-
ment for vertical control and anchorage. Pretorqued,
preangulated 0.018 × 0.025 inch edgewise appliances

456 Orsini
American Journal of Orthodontics and Dentofacial Orthopedics
April 2000
Fig 8. Posttreatment intraoral photographs.
Fig 9. Posttreatment casts.
Fig 11. Posttreatment cephalogram.
Fig 10. Posttreatment panoramic radiograph.

American Journal of Orthodontics and Dentofacial Orthopedics
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Volume 115, Number 4
Fig 12. Posttreatment cephalogram tracing.
Fig 13. Superimposition tracings.
were placed. The maxillary spaces were closed with
elastomeric chains and Class I elastics. Treatment
progress was good; because the mandibular alveolar
bone in the remaining edentulous space was healthy,
treatment goals were reevaluated. After a periodontal
consultation, an attempt was made to close the space.
The remaining maxillary spaces were closed with
0.016 × 0.022 stainless steel closing loops supported
with Class II elastics from the mandibular second
molars to the maxillary loops. An 0.016 × 0.022 stain-
less steel utility arch with an increased anchorage bend
was used to upright the roots of the mandibular second
molars. Total treatment time was 31 months.
RESULTS ACHIEVED
Posttreatment facial photographs (Fig 7) show an
improved facial profile with a sagittal reduction in lip
protrusion. The smile line was also improved. Dentally,

458 Orsini
American Journal of Orthodontics and Dentofacial Orthopedics
April 2000
a Class II molar, Class I canine relationship with ideal
overjet and overbite was achieved (Fig 8).
illary anterior teeth, and 0.0195 twisted wire lingual to
the mandibular anterior teeth were placed at the com-
pletion of active treatment. Instructions for the remov-
able retainers were 24 hr/day for the first year, then
nighttime wear. The stability of the mandibular space
closure is a concern. The patient was informed and is
being monitored closely.
The posttreatment dental casts (Fig 9) show good
dental interdigitation. Fortunately, the mandibular spaces
were closed with acceptable root parallelism (Fig 10).
No evidence of disease or root resorption is observed.
The final cephalogram (Fig 11) shows the dental
movements accomplished to correct the malocclusion.
The posttreatment cephalogram tracing (Fig 12) shows
tipping of the maxillary and mandibular anterior teeth
and intrusion of the maxillary first molars. Facial and
dental changes are best observed in the superimposi-
tion tracing (Fig 13).
FINAL EVALUATION
The result obtained is esthetically pleasing and
provides nice occlusal function in centric and eccen-
tric movements. Better interdigitation of the posterior
segments could be achieved by equilibrating posterior
interferences. The angulation of the mandibular
incisors to mandibular plane could be improved.
The periodontal condition was excellent during and
after treatment.
RETENTION
Maxillary and mandibular removable retainers, as
well as bonded 0.0175 twisted wire lingual to the max-