Download Orthosurgical Management of a Severe Class III Malocclusion

JIOS
CAse Report
Orthosurgical Management
of a Severe Class III Malocclusion
10.5005/jp-journals-10021-1258
Orthosurgical Management of a Severe
Class III Malocclusion
1
Amit Mendiratta, 2Anushka Aida Menezes Mesquita, 3Nandini Venkatesh Kamat, 4Vikas Dhupar
ABSTRACT
Success in the management of a skeletal Class III malocclusion
depends on proper diagnosis and treatment planning. In adults
with a severe discrepancy, combined orthosurgical approach is
the only way to achieve acceptable results.
This case report describes the orthosurgical management
of an adult male patient with a severe Class III malocclusion
displaying a combination of maxillary deficiency and mandibular
excess. The patient had a reverse overjet of 5 mm and an open
bite of 7 mm. Incisal display both at rest as well as on smiling
was decreased and he presented with a wide buccal corridor.
A combination of Arnett’s clinical and cephalometric
examination was used to diagnose and plan treatment for
facial changes. Double jaw surgery including a 4 mm maxillary
advancement and 4 mm rotation of the palatal plane downward
anteriorly with a 6 mm mandibular setback was planned. The
palatal plane was rotated downward to aid in closure of the open
bite thereby taking care of the decreased incisal show.
Ideal overjet, overbite, satisfactory facial balance and
stomato­gnathic function could be achieved because of a com­
bined orthosurgical approach.
Keywords: Orthosurgical, Class III, Maxillary deficiency,
Mandibular prognathism, Arnett’s cephalometrics.
How to cite this article: Mendiratta A, Mesquita AAM, Kamat
NV, Dhupar V. Orthosurgical Management of a Severe Class III
Malocclusion. J Ind Orthod Soc 2014;48(4):273-279.
Source of support: Nil
Conflict of interest: None
Received on: 9/7/13
Accepted after Revision: 23/7/13
Introduction
One of the most perplexing malocclusion to diagnose and
treat is the skeletal Class III malocclusion. ‘Angle’s Class
1
Senior Lecturer, 2Senior Resident, 3,4Professor and Head
III malocclusion’ and ‘mandibular prognathism’ were
previously regarded as similar entities until studies showed
that individuals who exhibit a Class III malocclusion present
a spectrum of abnormalities.1,2 Skeletal Class III malocclu­
ssion can involve either mandibular prognathism, maxillary
retrognathism, or a combination of both, along with vertical
and transverse problems. Ellis and McNamara1 in their
study of adult subjects with Class III malocclusion found a
combination of maxillary retrusion and mandibular protru­
sion to be the most common skeletal relationship.
The contribution of jaw bases to the malocclusion in
all three-dimensions along with the dentoalveolar and soft
tissue components needs to be thoroughly evaluated. Thus,
diagnosis remains the cornerstone in the successful manage­
ment of a skeletal Class III malocclusion. There has been a
paradigm shift in the diagnostic process and one of the most
efficient tools in an orthodontist’s diagnostic armamentarium
remains Arnett’s clinical and cephalometric facial and dental
planning.3-6
The role of heredity in the etiology of skeletal Class III
malocclusion is well established.7 Litton et al reported a
typical finding that one-third of a group of patients with
severe Class III malocclusion had a parent with the same
problem, and one-sixth had an affected sibling.8
The prognosis of early treatment in severe Class III
malocclusion remains controversial. Adults with a severe
Class III malocclusion are definitely not candidates for
ortho­dontic treatment alone as one of the main reasons for
seeking treatment is their lack of satisfaction with their
facial esthetics.9 Thus, combined orthosurgical management
remains the only possibility.
This case report shows the orthosurgical treatment
approach and results of an adult patient with a severe Class
III malocclusion.
1
Department of Orthodontics, Dharmsinh Desai University
Nadiad, Gujarat, India
2,3
Department of Orthodontics, Goa Dental College and Hospital
Bambolim, Goa, India
4
Department of Oral and Maxillofacial Surgery, Goa Dental
College and Hospital, Bambolim, Goa, India
Corresponding Author: Anushka Aida Menezes Mesquita
Senior Resident, Department of Orthodontics, Goa Dental
College and Hospital, Bambolim, Goa, India, Phone: 09823656679
e-mail: [email protected]
Diagnosis and Etiology
A 17-year-old male patient reported with a chief com­plaint
of a forwardly placed lower jaw and the inability to bite food
using the front teeth. The patient had no relevant medical
history.
Clinical frontal examination revealed a relatively symme­
t­rical face with an increased lower anterior facial height,
inferior sclera show, widened alar base and a long upper lip.
The Journal of Indian Orthodontic Society, October-December 2014;48(4):273-279
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Amit Mendiratta et al
There was no incisal show at rest with only half the maxil­
lary incisor crown show on smiling and an increased buccal
corridor evident (Figs 1A to D).
Clinical profile examination revealed a concave profile.
The patient had a deficient midface, flat cheekbone contour,
depressed nasal base, prominent nasal projection, obtuse
naso­labial angle, positive lip step, steep mandibular plane
angle and a long chin throat length (see Figs 1A to D).
Oral examination revealed good oral health with no
perio­dontal problems. The arches were symmetrical and
rela­tively well aligned. Mild mandibular anterior crowding
and minor rotations were evident in both the arches. Interarch
relationship showed a reverse overjet of 5 mm and an open
bite of 7 mm. Class III molar and canine relationship existed
in maximum intercuspation with bilateral posterior crossbite.
The mandibular midline was shifted by 1 mm to the left as
compared to the facial midline (Figs 2A to E). A simple
tongue thrust swallow was seen.
Temporomandibular joint examination revealed no
centric relation-centric occlusion discrepancy with any
history of pain or discomfort in the temporomandibular joint
or associated muscles.
Space analysis revealed a –2.5 mm deficiency in both
maxillary and mandibular arches with Bolton’s analysis
indicative of a 1.8 mm overall mandibular excess and
0.5 mm anterior excess.
Cephalometric examination revealed a skeletal Class III
malocclusion with a small sized retrognathic maxilla and a
large sized prognathic mandible with a hyperdivergent growth
pattern. Mild vertical maxillary deficiency was evident.
Maxillary incisors were mildly proclined with relatively
upright mandibular incisors. Soft-tissue profile showed a
concave profile with an increased nasal projection, obtuse
nasolabial angle, protrusive lower lip and increased throat
length. Upper lip length was increased with decreased incisor
exposure (Fig. 3A and Table 1).
The orthopantomograph revealed no temporomandibular
pathology (Fig. 3B).
The diagnostic summary of this postpubertal male was
skeletal Class III malocclusion comprising of a combination
of maxillary retrognathism and mandibular prognathism with
a hyperdivergent growth pattern. Intraorally, Angles Class
III malocclusion was present with anterior and posterior
crossbite, and anterior open bite with minor individual tooth
malpositions. Soft-tissue analyses revealed a concave profile
with mid face deficiency, long upper lip, reduced incisor
show and increased nasal and throat lengths.
Treatment Objectives
The objectives were to:
1. Attain a pleasing profile by correcting the deficient
midface and reducing the prominence of the lower jaw,
thus improving facial balance and profile.
2. Correct the generalized crossbite and anterior open bite.
3. Align the arches, correct inclinations and angulations of
the teeth.
4. Achieve an acceptable occlusion, both static as well as
functional.
5. Correct inadequate incisor show.
Treatment Alternatives
The severity of the sagittal jaw discrepancy made ortho­
surgical approach inevitable. Camouflage treatment alone
would not have addressed the patient’s chief complaint of
facial esthetics. Several treatment options were considered
for the patient.
Mandibular Setback Alone
Drawbacks
• Although the envelope of discrepancy allows up to 25 mm
of mandibular setback7, this surgery alone would have
caused an unesthetic ‘turkey gobbler’ appearance and
com­pro­mised the pharyngeal airway.
• Moreover, as maxillary deficiency contributed in a big
way to the patient’s problem, setting only the mandible
Figs 1A to D: Pretreatment extraoral photographs: (A) Frontal, (B) profile, (C) three quarter and (D) smiling
274
JIOS
Orthosurgical Management of a Severe Class III Malocclusion
Figs 2A to E: Pretreatment intraoral views: (A) Right lateral, (B) frontal, (C) left lateral, (D) maxillary occlusal and
(E) mandibular occlusal
Figs 3A and B: Pretreatment X-rays: (A) Lateral cephalogram and (B) orthopantomogram
back would tend to accentuate the prominence of both
nose and the soft tissue deficiency of the midface.
Onlay grafts7 could have been used in conjunction with
the mandibular setback surgery in order to compensate for
the midface deficiency; however, these too are associated
with a number of drawbacks as follows:
• Onlay grafts are unpredictable.
• The grafted area could be firm to touch unlike the adjoi­
n­ing nongrafted areas.
Maxillary Advancement Alone
Drawbacks
• Although in the hierarchy10 of stability, maxillary advance­
ment is considered a more stable option, large amounts of
maxillary advancement to match a prognathic mandible
would not have been esthetically pleasing for the patient.
A reduction genioplasty7 could have been added to the
above surgery; however, with this genioplasty, it is difficult to
avoid flaccidity and wrinkling of the submental soft tissue—an
esthetic results are unpredictable.
Double Jaw Surgery: Maxillary
Advancement and Mandibular Setback
Single jaw surgical procedures with or without adjunctive
surgeries would not have corrected the occlusion and more
importantly facial esthetics to a satisfactory level in this
patient.
A combination of maxillary advancement and mandibular
setback would help to achieve all necessary treatment objec­
tives and was thus planned for this patient.
Treatment Plan
A presurgical phase of orthodontics comprised of a nonextrac­tion therapy that was essential to align the arches
and to remove any compensation evident. Decompensation
was not required in the mandibular arch as the mandibular
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Amit Mendiratta et al
Table 1: Cephalometric summary
Cephalometric
variable
Pretreatment
Presurgical
Posttreatment
Cranial base
SN length (mm)
SN-FH (deg)
70.5
2
71
2
71
2
Maxilla
SNA (deg)
Eff Mx Length (mm)
N perpend. to pt. A (mm)
86
87
–1
86
87
–1
85
89
0
Mandible
SNB (deg)
Eff mand length (mm)
B perpend. (MP) to Pg (mm)
NB to Pg (mm)
86
126
–5
0.5
86
126
–2
1
85
124
–2
2
Maxilla-mandible
ANB (deg)
Wits (mm)
Mx-Mn differential (mm)
0
–7
39
0
–11
39
2
–3
37
Vertical relation
FMA (deg)
SN-GoGn (deg)
Saddle angle
Articular angle
Gonial angle
LAFH (ANS-Me) mm
Y-Axis (deg)
Jarabak’s ratio
Base plane angle
Inclination angle
Mx OP to TVL (deg )
34
36
111
163
122
74
61
61.2%
26
84
94
34
36
111
162
123
72.5
60
60.4%
26
84
96
35
37
112
162
127
72
60
61.9%
27
81
101
Dental parameters: maxilla
1 to NA (mm)
1 to NA (deg)
1 to A (mm)
1 to TVL (mm)
1 to Mx OP (deg)
1 to NF (mm)
6 to NF (mm)
4.5
29
5
–15
55
25
19
4
24
3.5
–14
58
27
26
7
27
7.5
–10
54
29
26
Dental parameters: mandible
1 to NB (mm)
1 to NB (deg)
1 to A-Pg (mm)
IMPA
1 to TVL (mm)
1 to Mn OP (deg)
1 to MP (mm)
6 to MP (mm)
10
37
9
97
–8
67
42
36
10
34
9
93
–7
70
43
37
6
24
4.5
85
–12.5
72
44
37
Mx-mand
Overjet (mm)
Overbite (mm)
Interincisal angle
–5
–7
113
–6.5
–5
121
3
2.5
132
Soft tissue
Nasolabial angle
Upper lip angle
Upper lip length (mm)
Mx 1 exposure (mm)
G-Sn-Pg
E line to upper lip
E line to lower lip
123
0
26
0
159
–4
4.5
117
10
26
0
164
–3
7.5
107
11
25
1.5
160
–2
3
276
teeth were rather upright. Slenderization was planned in
the maxillary arch in order to correct the mildly proclined
incisors. No vertical decompensation was required.
A Le Fort I osteotomy with 4 mm maxillary advancement
and 4 mm anterior downward rotation of palatal plane to
close the open bite along with a bilateral sagittal split osteo­
tomy of 6 mm mandibular setback was planned. This was to
be followed by a short phase of postsurgical orthodontics to
achieve desired tooth interdigitation.
Treatment Progress
Presurgical Orthodontic Phase
The presurgical phase was initiated with 0.022" MBT preadjusted edgewise appliance. The maxillary and mandibular
arches were aligned using 0.016" NiTi archwires which
were followed by progressively heavier archwires, such
as 0.018" stainless steel, 0.017 × 0.025" stainless steel and
finally 0.019 × 0.025" stainless steel.
Before surgery, upper and lower co-ordinated 0.019 ×
0.025" stainless steel wires were left passively in place for
4 weeks following which presurgical records were taken
(Figs 4 to 6).
Two surgical splints were fabricated, one ‘intermediate’
and the other ‘final’. Reference lines and cuts were placed
according to the mock surgery as demonstrated by Epker,
Stella and Fish.11 Maxillary and mandibular third molars
were extracted 6 months prior to surgery.
Surgical Phase
During surgery, the maxilla was first mobilized with the
Le Fort I osteotomy to advance the maxilla by 4 mm and rotate
the palatal plane down anteriorly by 4 mm to close the open
bite. The new position of the maxilla was stabi­lized using
L-shaped surgical plates anteriorly and wires posteriorly with
the help of the ‘intermediate splint’. The man­dible was then
setback by 6 mm using a bilateral sagittal split osteotomy
(BSSO). The ‘final splint’ was then used to posi­­­­tion and stabi­
lize the mandible with the help of surgical plates.
Postsurgical Phase
Four weeks postsurgery the stabilizing archwires and splint
were removed. Postsurgical leveling and final detailing were
achieved with 0.014" stainless steel archwires and settling
elastics. Total treatment time was 30 months. The patient
was then debonded and fitted with upper and lower retainers.
Treatment Results
Most of the treatment objectives were achieved. There was
a marked improvement in facial esthetics with fullness in
paranasal areas, upper lip support, and no unesthetic sagging
JIOS
Orthosurgical Management of a Severe Class III Malocclusion
Figs 4A to D: Presurgical extraoral photographs: (A) Frontal, (B) profile, (C) three quarter and (D) smiling
Figs 5A to E: Presurgical intraoral views: (A) Right lateral, (B) frontal, (C) left lateral, (D) maxillary occlusal and (E) mandibular occlusal
Figs 6A and B: Presurgical X-rays: (A) Lateral cephalogram and (B) orthopantomogram
of throat. Crossbite and anterior open bite were corrected.
The incisor shows at rest and smiling was vastly improved.
The smile of the patient was also enhanced as the width of the
buccal corridor was reduced with maxillary advancement.
The alar cinch done during surgery prevented further wide­
n­ing of the alar base12 (Figs 7A to D).
Both the maxillary and mandibular arches were well aligned
and a Class I buccal occlusion was achieved (Figs 8A to E).
Cephalometric superimposition showed a marked improve­­­­­
ment in the facial profile with facial harmony in the nose, lips
and chin projections and an excellent esthetic balance between
the hard and soft tissue (Figs 9 and 10).
The Journal of Indian Orthodontic Society, October-December 2014;48(4):273-279
277
Amit Mendiratta et al
Figs 7A to D: Post-treatment extraoral photographs: (A) Frontal, (B) profile, (C) three quarter and (D) smiling
Figs 8A to E: Post-treatment intraoral views: (A) Right lateral, (B) frontal, (C) left lateral, (D) maxillary occlusal and (E) mandibular occlusal
Discussion
In severe cases of Class III malocclusion, orthodontics alone
is not possible and an orthosurgical approach becomes inevi­
table in order to improve occlusion, masticatory funct­ion and
more importantly esthetics and facial balance.
The final facial profile with orthognathic treatment is
of great significance as it results in sudden and dramatic
changes which can have a deep psychological impact on the
patients’ self-esteem. For this reason, diagnosis and treat­ment
planning become crucial.13 Early in treatment planning, it is
necessary to ascertain the components contri­buting to the
malocclusion, whether it is due to a prognathic mandible, or
a retrognathic maxilla or a combination of these possibilities.
Visual examination is as important as radio­graphic analysis
for correct diagnosis. There has been a paradigm shift in the
diagnostic process. It is no longer occlusion centric. Positions
and lengths of all components, soft tissue, bone and teeth
in all three-dimensions can be evaluated. One of the most
278
efficient tool in the orthodontist’s diagnostic armamentarium
remains Arnett’s clinical and cephalometric facial and dental
planning which provides a more sophisticated and accurate
method of deciding the needs of a case.3-6
In this patient, a nonextraction presurgical phase of
orthodontics was carried out to align the arches and correct
the upper incisor torque and mild proclination followed by a
combi­nation of surgical maxillary advancement and mandi­
bular setback. Correction of incisor torque, leveling and align­
ment of arches by orthodontics is necessary before surgery
for complete correction of the jaw discrepancy and ideal
facial outcomes from surgery. Thus, presurgical orthodontics
has to be well planned.
Clinical success after orthognathic therapy can be defined
as a combination of following factors: patient satisfaction,
correct static and functional occlusion, patient comfort, chew­
ing, no pain in the temporomandibular joint and stability
of results. Bailey et al14 evaluated long-term soft-tissue
changes after orthodontic and surgical corrections of skeletal
JIOS
Orthosurgical Management of a Severe Class III Malocclusion
Figs 9A and B: Post-treatment X-rays: (A) Lateral cephalogram and (B) orthopantomogram
Fig. 10: Cephalometric superimposition
Class III malocclusions and concluded that Class III
patients are less stable during the first year after surgery but
show fewer changes in hard and soft-tissue measurements
beyond that point. This patient has been followed for the
past 10 months following debonding and has showed no
signs of instability so far. However, long-term evaluation is
necessary,15,16 and will be carried out in this case.
Conclusion
Class III malocclusion can be treated by using different
methods, with each having its own advantages and dis­
advan­tages. The structures involved in this abnormality,
the facial and dentoalveolar compensations present and
the patient’s expectations must be taken into consideration
during treatment planning for satisfying results.
It was gratifying to see the change in the patient’s
perception and increased levels of confidence at the comple­
tion of treatment.
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