Download Class III malocclusion with missing maxillary lateral incisors

CASE REPORT
Class III malocclusion with missing maxillary
lateral incisors
Mauro Cozzani,a Luca Lombardo,b and Antonio Graccoa
Ferrara, Italy
A 23-year-old woman with a skeletal Class III relationship, a normal vertical jaw relationship, and missing maxillary lateral incisors was treated with bidimensional fixed edgewise appliance therapy combined with orthognathic surgery. A functional and esthetic occlusion in an improved facial profile was established at the end of
the surgical and orthodontic treatment. Pretreatment, posttreatment, and long-term follow-up records for the patient are presented. (Am J Orthod Dentofacial Orthop 2011;139:388-96)
C
lass III malocclusion can involve only the dentition, or it might be complicated by a poor
relationship between the maxilla and the mandible. In the former situation, the mandibular first molar is
positioned half a cusp toward the midline with respect to
the maxillary molar, whereas the latter type also involves
a poor relationship between the maxilla and the mandible in the sagittal plane, caused by maxillary retrusion or
mandibular protrusion.1 In addition, a retruded maxilla
is frequently accompanied by skeletal constriction in
the transverse plane.2 The majority of Class III patients
have both dentoalveolar and skeletal components.3-5
Various factors are implicated in the etiology of
a Class III malocclusion: heredity (eg, race), environmental factors (eg, functional anterior deviation of the
mandible or mouth breathing, which can be a positive
stimulus for mandibular growth), and several pathologies (eg, pituitary tumors responsible for acromegaly).6
The incidence of this type of malocclusion in white
populations varies between 1% and 5%; in Asian
populations, it reaches an upper range between 9%
and 19%; and in Latin populations, it is about 5%.7,8
Early treatment of Class III malocclusion reduces the
necessity of a second phase of treatment.1 Several
studies have reported that Class III skeletal discrepancies
worsen with age.9,10 Thus, the difficulty in treating
preadolescent patients successfully increases over time.
a
Visiting Professor, Department of Orthodontics, University of Ferrara, Italy.
Adjunct Professor, Department of Orthodontics, University of Ferrara, Italy.
The authors report no commercial, proprietary, or financial interest in the
products or companies described in this article.
Reprint requests to: Mauro Cozzani, Department of Orthodontics, University of
Ferrara, 44100, Ferrara, Italy; e-mail, [email protected].
Submitted, April 2009; revised and accepted, September 2009.
0889-5406/$36.00
Copyright Ó 2011 by the American Association of Orthodontists.
doi:10.1016/j.ajodo.2009.09.022
b
388
Nonetheless, most patients with severe skeletal Class III
malocclusion are candidates for orthognathic surgery in
adulthood, the only means of obtaining functional
occlusion and an esthetically pleasing profile.11 Moreover,
many adults presenting for comprehensive orthodontic
therapy have additional dental and periodontal problems
that require multidisciplinary treatment approaches.
The aim of this case report was therefore to present
the interdisciplinary treatment of an adult patient with
a Class III malocclusion complicated by missing maxillary
lateral incisors.
DIAGNOSIS AND ETIOLOGY
A 23-year-old woman reported with the principal
complaint of unsatisfactory esthetic appearance of her
teeth. Her medical history showed no contraindication
to orthodontic therapy, and no history of trauma or
serious illness. Facial photographs showed maxillary
retrusion and severe mandibular protrusion with an
unesthetic smile (Fig 1). Intraoral examination of the
maxillary dental arch showed a transverse skeletal
constriction, a diastema between the central incisors,
and congenital absence of the permanent lateral incisors.
In the mandibular arch, on the other hand, mild incisor
crowding, and anterior and bilateral crossbite with negative overjet ( 6.5 mm) were evident. The tooth discoloration was probably due to tetracycline administration
during dental development. Class III molar and canine relationships were observed on both the right and left sides.
The mandible deviated toward the right. The maxillary
left lateral incisor edentulous space had been partially
closed by migration of the adjacent teeth (Fig 2).
Evaluation of the panoramic radiograph confirmed
that the maxillary lateral incisors were missing and
showed the impacted maxillary and mandibular third
molars (Fig 3). Cephalometric analysis showed a skeletal
Cozzani, Lombardo, and Gracco
389
Fig 1. Pretreatment photographs.
Fig 2. Pretreatment dental casts.
Class III relationship, normal vertical jaw proportions
(SNA-SNP/Go-Gn, 23 ), and inclined mandibular
incisors (lower incisor^GoGn, 84 ).
TREATMENT OBJECTIVES
The skeletal objectives for this patient were correction
of the maxillary position and asymmetrical mandibular
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Cozzani, Lombardo, and Gracco
390
Fig 3. Pretreatment radiographs and cephalometric tracing.
prognathism. The dental objective of treatment
was closure of the lateral incisor spaces to establish
a functional occlusion with normal anterior overbite
and overjet.
TREATMENT ALTERNATIVES
Three treatment options were proposed to the patient.
The first would involve orthodontic treatment of the maxillary and mandibular arches, reopening of the maxillary
lateral incisor space, and surgical treatment to correct
the vertical and sagittal skeletal discrepancies. This option
would also include replacing the missing maxillary lateral
incisors with 2 dental implants. Although this solution
would produce Class I molar and canine relationships on
both sides, the gingival contour and margin levels would
be critical and difficult to control in the long term.
Another option consisted of closing the spaces left by
the congenitally missing teeth before bimaxillary surgery. This choice would also require restoration of the
maxillary canines to resemble lateral incisors and the first
premolars to simulate canines.
The third choice was nonsurgical orthodontic treatment. This option would involve extraction of the mandibular first premolars and replacement of the missing
maxillary lateral incisors with 2 dental implants. The
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premolar extractions and opening of the lateral incisor
spaces would permit resolution of the anterior crossbite
and achieve an occlusal compromise. However, neither
facial esthetics, skeletal asymmetry, nor the transverse
discrepancy would be improved.
After consultation, the patient chose the second option, and her treatment course and outcome are detailed
below.
TREATMENT PLAN
Levelling and alignment of both arches and closure of
the lateral incisor spaces were the first steps. Then LeFort I
surgery would be used to correct the vertical and transverse skeletal discrepancies and to assist in sagittal coordination of the mandible. Finally, bilateral sagittal split
ramus osteotomy would be used to correct the asymmetry,
prognathism, sagittal maxillomandibular relationship,
and dental malocclusion. The final steps would be occlusal
finishing and restorative rehabilitation of the maxiillary
canines and first premolars to substitute as lateral incisors
and achieve adequate occlusal and esthetic results.
TREATMENT PROGRESS
The mandibular third permanent molars and maxillary right deciduous lateral incisor were extracted.
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Cozzani, Lombardo, and Gracco
391
Fig 4. Leveling and alignment.
Although a bidimensional appliance was used initially,
the maxillary second molars were not bonded, and the
maxillary canines were fitted with conventional fixed
appliances (0.022 3 0.028 in) to facilitate sliding
mechanics of the maxillary central incisors.
Leveling and alignment were begun with a 0.014-in
nickel-titanium archwire and completed with a 0.016 3
0.022-in stainless steel wire. Space closure was achieved
by using 0.018 3 0.022-in stainless steel archwires, selected to maintain incisor torque control (0.018 3
0.025-in slot) and reduce friction on the canines, premolars, and molars during incisor retraction (brackets,
0.022 3 0.028 in) (Fig 4).
After bimaxillary surgery, esthetic recontouring of
the maxillary canines was accomplished by using
a combination of grinding and composite resin buildups
(Fig 5). In addition, the maxillary canines, which had
been reshaped as lateral incisors, were fitted with new
0.018 3 0.025-in brackets (bidimensional prescription)
to provide precise control of torque and tipping, and
the mandibular second molars were banded. After rebracketing of the maxillary canines (lateral incisors),
a 0.016 3 0.022-in Quad-Cat (GAC International,
Bohemia, NY) archwire was placed.
Subsequently, space was opened by using an 0.018
3 0.025-in stainless steel archwire, and a coil spring on
the left side was used to prepare the first premolars for
restoration with canine-shaped ceramic crowns. Ultimately, individualized extrusion and intrusion of the
canines (lateral incisors) and first premolars (canines)
were performed to obtain optimum marginal gingival
contours for the anterior teeth (Fig 6). Final detailing,
involving 8 months of treatment time, was completed
with 0.018 3 0.025-in stainless steel archwires.
TREATMENT RESULTS
At the end of treatment, Class I canine and Class II
molar relationships were achieved, and overbite and
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Fig 5. Esthetic recontouring of the maxillary canines.
Fig 6. Individualized extrusion and intrusion of the canines (lateral incisors) and first premolars (canines) to improve gingival contours.
overjet were within the normal limits. Facial appearance
and skeletal balance were improved, and mandibular
asymmetry and prognathism had been corrected.
Despite the missing lateral incisors, the patient
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appeared to exhibit a natural intact dentition (Figs 7
and 8).
The cephalometric changes included increases in
the ANB angle (almost ideal) and Wits appraisals, an
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Fig 7. Posttreatment photographs.
Fig 8. Postreatment dental casts.
improvement in the lip relationship, and no variation in
lower vertical face height (Table). Superimposition of the
pretreatment and posttreatment cephalometric tracings
showed that mandibular retraction was achieved by
slight downward and forward movement of the maxilla,
as well as minor maxillary incisor proclination (Fig 9).
Long-term records were collected 2 years after treatment (Figs 10 and 11). Posttreatment and long-term
cephalograms and superimposed tracings demonstrated
minimal anteroposterior changes in incisor position and
little or no surgical relapse.
DISCUSSION
Almost 30% of adult orthodontic patients require
multi-disciplinary management to obtain optimal treatment outcomes.12 Often, functional and esthetic results
can only be achieved by a combination of surgery,
orthodontics, and prosthodontic rehabilitation.13
In this patient, the missing lateral incisors complicated the treatment of the Class III skeletal malocclusion.
Orthodontic treatment of missing teeth comprises 2
alternatives: closure or opening of the edentulous
spaces.14-22 Many clinicians prefer to create space for
missing lateral incisors with single-tooth implants or
resin-bonded bridges,21,22 but, in this case, we decided
to close the spaces because of the permanence and the
biologic compatibility of the result.23
Managing patients with congenitally missing maxillary lateral incisors raises several important issues
concerning the amount of space, the patient’s age, the
type of malocclusion, and the condition of the adjacent
teeth. One of 3 treatment options can be selected when
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Fig 9. Posttreatment radiographs and superimposed cephalometric tracings.
replacing missing lateral incisors: canine substitution,
a tooth-supported restoration, or a single-tooth
implant. There are also specific criteria that must be
addressed when choosing an appropriate treatment option. The primary consideration must be conservation,
and, in general, the treatment of choice should be the
least invasive option that satisfies the expected esthetic
and functional objectives.
In this context, the orthodontist plays a key role by
achieving specific space requirements and positioning
teeth in an ideal restorative position. For example, canine
substitution can be an excellent treatment option for
replacing missing lateral incisors from an esthetic perspective. However, if this treatment is unsuitable for the patient
in question, the final result might be less than ideal.
Ultimately, an interdisciplinary approach is the most
predictable way of achieving optimal final esthetics.24
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According to Rosa and Zachrisson,25,26 Class III
treatment with space closure can be difficult to obtain,
but a natural-looking result is possible with good collaboration. Fundamental to clinical success are careful
correction of the crown torque, esthetic recontouring,
and intentional whitening of the mesially relocated
canine. Furthermore, to obtain an optimal level for the
marginal gingival contours of the anterior teeth, individualized extrusion and intrusion of the canines and first
premolars are necessary.
In contrast, replacing the missing lateral incisors with
a single-tooth implant and prosthetic crown would
commit the patient to a lifelong artificial restoration in
a highly visible area of the mouth. In this region, tooth
hue and transparency, along with gingival color,
contour, and marginal levels are critical and difficult to
control, particularly over time.27,28
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395
Fig 10. Photographs 2 years posttreatment.
Fig 11. Cephalometric radiograph and tracing 2 years posttreatment.
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Table. Cephalometric analysis
Initial Final Posttreatment
Sagittal skeletal relationships
81.5 82
82
Maxillary position: S-N-A ( )
85
81
81.5
Mandibular position: S-N-Pg ( )
Sagittal jaw relationship: A-N-Pg
3.5
1
0.5
(mm)
Vertical skeletal relationships
13
11.5
11.5
Maxillary inclination:
S-N/ANS-PNS ( )
36
37
34.5
Mandibular inclination:
S-N/Go-Gn ( )
Vertical jaw relationship:
23
23.5
23
S-N/Go-Gn (mm)
Dento-basal relationships
116
122
121
Maxillary incisor inclination:
1-ANS-PNS ( )
84
91
90
Mandibular incisor inclination:
1_ -Go-Gn ( )
Mandibular incisor
2.5
6
5
compensation: 1_ -A-Pg (mm)
Dental relationships
Overjet (mm)
6.5
3
3
Overbite (mm)
4.5
2
2.5
136.5 126
127
Interincisal angle: 1/1_ Treatment outcomes and long-term results demonstrated that combined orthodontic surgery and prosthodontic treatment of a Class III malocclusion can provide
a stable, intact dentition, despite the congenital absence
of the lateral incisors.
CONCLUSIONS
Interdisciplinary treatment combining orthodontics,
surgery, and prosthodontics helped to achieve good esthetic and functional results in an adult with a Class III
skeletal malocclusion and missing lateral incisors.
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