case report · 2020-03-09 · the mandibular second premolars are the most frequent congenitally...
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53Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
INTRODUCTION
For correction of skeletal Class III malocclusion,
Proffit states that there are three treatment options: 1)
growth modification, use differential growth of the maxilla
relative to the mandible; 2) camouflage of the skeletal
discrepancy through tooth movements to correct the
dental occlusion while maintain the skeletal discrepancy;
or 3) orthognathic surgical correction.1 The treatment
option is depending on the patient’s age, the facial
profile, the skeletal pattern, the alveolar bone reaction
on mandibular incisors, and the severity of malocclusion
before treatment.
As for anterior cross bite, except some patients are
truly skeletal Class III malocclusion, some others are
pseudo-Class III malocclusion. These pseudo-Class III
patients may present some characteristics as: 1) normal
or mildly larger size of mandible; 2) normal or mildly
smaller size of maxilla; 3) incisors could be guided to
edge-to-edge in resting position; 4) difference between
centric occlusion (CO) and centric relation (CR); 5) first
molars may occlude in Angle’s Class III relationship.
The profiles of pseudo-Class III patients usually are
concave, upper lips are less prominent due to insufficient
support of upper incisors, while soft tissue menton and
lower lips are more protrusive, but these Class III profiles
Case Report
This 22-year-old female presents with skeletal Class III malocclusion, complicated by anterior cross bite,
deep bite, and congenital missing of bilateral mandibular second premolars. The treatment modality was full-
mouth fixed edgewise appliances. A favorable result of ideal overbite and overjet and closure of bilateral spaces
of missing teeth were achieved. The patient was satisfied the improvement of function and esthetics after
treatment. (Taiwanese Journal of Orthodontics. 31(1): 53-63, 2019)
Keywords: pseudo-Class III malocclusion; anterior cross bite; deep bite; congenital missing.
The OrThOdOnTic TreaTmenT Of class iii malOcclusiOn wiTh anTeriOr crOss biTe and
severe deep biTe
Chieh Yang, Yu-Chuan TsengSchool of Dentistry, College of Dental Medicine,
Kaohsiung Medical University, Kaohsiung, TaiwanDepartment of Orthodontics, Dental Clinics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
Received: September 11, 2018 Revised: March 16, 2019 Accepted: March 31, 2019Reprints and correspondence to: Dr. Yu-Chuan Tseng, Department of Orthodontics, Kaohsiung Medical University Hospital, No. 100, Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan. Tel: +886-7-3121101 ext 7009 Fax: +886-7-3221510 E-mail: [email protected]
54 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
The extraoral examination revealed that the patient
had skeletal Class III malocclusion with midface
deficiency, mandibular prognathism, acceptable lower
facial height, insufficient display of upper incisors while
smiling (Figure 1).
The intraoral examination revealed that the patient
had Angle’s Class III malocclusion with anterior crossbite
and deep bite with an accentuated curve of Spee in
the lower arch and supra-eruption of lower incisors.
The dental spaces in the lower arch resulted from the
congenital missing of bilateral lower second premolars
(Figures 1, 2). Besides, this patient was a pseudo-Class
III malocclusion since her mandible could be guided to
incisors edge to edge position (Figures 3, 4). The initial
cephalometric analysis revealed that this patient was
skeletal Class III malocclusion with normal mandibular
plane angle, retroclined upper and lower incisors and
retrusive upper lip (Figures 5, Table 1).
are much improved in rest position while incisors are
in edge to edge position. Anterior crossbite has been
associated with a variety of complications, such as
gingival recession of the lower incisors, incisal edge wear,
and eventually lost of these teeth. Correction of anterior
crossbite could enhance the oral health and achieve
better occlusion. The aim of this article is to present the
treatment of a pseudo-Class III malocclusion in an adult
patient complicated by deep bite and congenital teeth
missing.
CASE REPORT
A 22-year-old female patient who had no history
of illness or trauma, presented the following complaints
including anterior crossbite and mandibular protrusion.
The dental spaces in the lower arch came from congenital
tooth missing.
Figure 1. Extraoral and intraoral photographs, before treatment.
Yang C, Tseng YC
55Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Anterior Cross Bite with Deep OB
Figure 2. Study models, before treatment.
Figure 3. Intraoral photographs before treatment. The mandible could be guided to edge to edge bite.
56 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Yang C, Tseng YC
Table 1. Cephalometric measurements before and after treatment.
Measurement Pre-tx Post-tx Normal Range
SNA 79.0 80.0 79.8 ~ 83.2
SNB 80.0 78.5 75.7 ~ 78.7
ANB -1.0 1.5 3.2 ~ 5.0
SN-MP 36.0 38.0 33.8 ~ 38.4
U1 to NA mm 4.0 7.5 4.3 ~ 8.1
U1 to SN° 92.0 104.5 103.85 ~ 108.75
U1 to NB mm 7.5 6.0 5.4 ~ 10.2
U1 to MP° 78.0 77.0 93.4 ~ 99.2
E-line: Upper -3.5 -0.5 0.7 ~ 3.1
E-line: Lower 0.0 0.0 0.1 ~ 3.4
Figure 4. The lateral facial profile in: A , centric occlusion; B , edge-to-edge incisal contact.
Figure 5. A , lateral cephalometric film; B , panoramic radiograph before treatment.
A B
A B
57Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Anterior Cross Bite with Deep OB
also used to correct the anterior crossbite and rotate the
mandible in clockwise direction. Thus, mild mandibular
protrusive posture was improved by the Class III
mechanics.
Treatment progressOrthodontic treatment was carried out by using
the pre-adjusted 0.022-inch slot self-ligation system,
and lower anterior resin bite blocks were also added in
the initial stage to disocclude the bite and facilitate the
correction of anterior crossbite (Figure 6). It took about
seven months to accomplish the leveling and alignment
and correct the anterior crossbite. Reposition of some
brackets to calibrate the position and root angulation after
mid-term panoramic film taking. Continuing the crossbite
correction and closing the residual mandibular spaces
were accomplished in another nine months. After a total
treatment duration of 32 months, the upper wraparound
retainer and the lower fixed retainer were used for
retention (Table 2).
Diagnosis● Skeletal Class III jaw relation
● Orthodivergent facial pattern
● Angle’s Class III malocclusion
● Anterior crossbite and deep bite
● Congenital missing of #35, 45
Treatment objective● To correct the anterior crossbite and deep bite, achieve
normal overbite and overjet by upper anterior teeth
proclination and lower anterior teeth retraction.
● To improve the facial profile and lip posture.
● To close the mandibular dental space.
Treatment planNo further tooth extraction was planned for this
patient. Full-mouth fixed edgewise appliances were
bonded for leveling and alignment in the upper and lower
dentition. The mandibular space was closed by lower
anterior retraction and intrusion. Class III elastic was
Figure 6. Full mouth bonded with fixed appliance with light wire leveling and bite block in the lower anterior teeth.
58 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
second premolars. Canine relation was finished in Class
I relationship by lower anterior retraction and Class III
elastics. The superimposition of cephalometric tracings
revealed that the upper incisors were proclined, and the
upper lip also became more prominent after treatment.
In addition, the upper first molar was mesialized; lower
incisors were retracted and intruded while lower first
Treatment resultsThe facial profile maintained in mild concave at
midface (Figure 7). Normal overbite and overjet, Class
I canine relationships as well as coincident facial and
dental midlines were achieved (Figure 8). The molar
relation was finished in bilateral Class III due to the dental
space closure of congenital missing mandibular bilateral
Yang C, Tseng YC
Table 2. Summary of treatment progress.
Upper Lower
103 / 11 ~ 104 / 06
• Bonding • Leveling and alignment • Crossbite correction - short Class III elastics
• Bonding • Leveling and alignment • Crossbite correction - short Class III elastics
104 / 06 ~ 105 / 03 • Keeping crossbite correction • Spaces closure
105 / 03 ~ 105 / 10 • Releveling • Releveling and Keeping flattening curve of Spee
105 / 10 ~ 106 / 07 • Finishing and detailing • Finishing and detailing
106 / 07 • Debonding - wraparound retainer
• Debonding - 34-44 fixed retainer
Figure 7. The facial and intraoral photographs, after treatment.
59Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Anterior Cross Bite with Deep OB
to mandibular plane angle (SN-MP) also increased from
36° to 38°. The distance between upper incisor to NA line
increased from 4 mm to 7.5 mm, and the angle between
upper incisor to SN plane increased from 92° to 104.5°.
The lip posture was improved by increase the distance of
upper lip to E-line from -3.5 mm to -0.5 mm (Table 1).
molar was mesialized and extruded; and the mandible
showed clockwise rotation (Figure 9, 10). The root
parallelism and root resorption were acceptable and within
the normal range (Figure 11). The cephalometric analysis
comparing the initial and final conditions indicted that
the ANB angle increased from -1° to 1.5°, the SN line
Figure 8. The study models, after treatment.
Figure 9. Superimposition of cephalometric tracings. Black line, before treatment; red line, after treatment.
60 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Yang C, Tseng YC
Figure 11. A , lateral cephalometric film; B , panoramic radiograph, after treatment.
Figure 10. Regional superimposition of cephalometric tracings. A , maxilla; B , mandible; black line, before treatment; red line, after treatment.
A B
A
B
61Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Anterior Cross Bite with Deep OB
fixed appliances with Class III elastics and bondable resin
bites for disocclusion was effective to correct the anterior
crossbite. The anterior resin bites also help to intrude the
supra-eruptive lower anterior teeth. The upper teeth show
was insufficient before treatment. By flaring of upper
anterior incisors, the crowding in upper dentition was
relived and the pleasing smile curve was also achieved.
The patient’s upper lip rests on the gingiva margin of
upper incisors when smile. The tooth show exceeds the
proposed minimum of 0 to 2 mm of upper lip coverage
of the anterior teeth for posed smile in Asian female
standard.11
In treating anterior crossbite with camouflage
orthodontic treatment, lingual tipping of lower anterior
teeth may result in wash-board appearance and periodontal
damage. The cephalometric analysis indicated the change
of lower incisor inclination was few ( L1-MP: 78° to 77°).
The reasons for the few change in the lower incisors may
be attributed to: (1) light force and short distance of Class
III elastics (3/16” 2 oz) were applied when small-sized
initial working NiTi wires (0.013 / 0.014 inch) were used
to avoid unwanted side effect of over-retraction in lower
anterior teeth; (2) gradually increase the size of working
wires with appropriate amount of buccal crown torque in
lower anterior teeth when closing lower dental space; (3)
the combination of pre-torque NiTi wire (.017 x .025 NiTi
with 20 degree lingual root torque) for torque control of
lower anterior teeth.
The mandibular second premolars are the most
frequent congenitally missing teeth followed by
mandibular and maxillary lateral incisors.12
The etiology
of tooth agenesis is considered to involve the disturbance
of dental development by genetic factors, environmental
factors, or combination of both. Many researchers have
reported that tooth size is often smaller in patients with
tooth agenesis than in patients without tooth agenesis.13-18
Two treatment approaches are available to solve the
missing tooth space: (1) close the spacings and allow the
permanent first molar drift mesially and then complete
DISCUSSION
For correction for skeletal Class III malocclusion,
there are three main treatment options: growth
modification, orthodontic camouflage therapy, and
surgical-orthodontics. Growth modification by dentofacial
orthopedic appliances is an effective method to resolve
skeletal Class III jaw discrepancies in children.2-5
Proffit
indicated the criteria of case selection to enhance the
outcome of orthodontic camouflage therapy, including: (1)
average or short facial pattern; (2) mild anteroposterior
jaw discrepancy; (3) crowding less than 4-6 mm; (4)
normal soft tissue features (nose, lips, chin); (5) no
transverse skeletal problem. Tseng et al. used the receiver
operating characteristic analysis of cephalometric
var iab les to d i s t inguish the ske le ta l Class I I I
malocclusions who requiring orthognathic surgery. There
should meat 4 of these 6 measurements that indicated for
surgical treatment: (1) overjet, ≦ –4.73 mm; (2) Wits
appraisal, ≦ –11.18 mm; (3) L1-MP angle, ≦ 80.8°;
(4) Mx/Mn ratio, ≦ 65.9%; (5) overbite, ≦ –0.18 mm;
and (6) gonial angle, ≧120.8°.6 For this patient, only
2 of these 6 measurements (L1-MP angle=79°; gonial
angle=122°) met the surgical indication. Besides, this
patient had average facial pattern, mild anteroposterior
jaw discrepancy with upper dentition crowding, no
transverse skeletal problem; patient’s incisors could be
shifted to edge to edge position with relative normal
soft tissue features in this position; so, this patient was
arranged for camouflage orthodontic treatment.
For correction of the anterior crossbite, disoccluding
the bite for unrestricted pathway in the initial tooth
movement is essential. Various treatment methods have
been proposed to correct anterior dental crossbite, such
as tongue blades, reversed stainless steel crowns, fixed
acrylic planes, bonded resin-composite slopes and
removable acrylic appliances with finger springs.7-10
The
aforementioned appliances might be huge, uncomfortable,
and only applicable in young patients. For adult patients,
62 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
between skeletal or dental Class III malocclusion. The
factors in identifying the patient as dental or skeletal Class
III malocclusion and the factors in achieving good results
of camouflage treatment were reviewed. The patient with
dental Class III malocclusion can be well treated with
proper evaluation and camouflage treatment.
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As for this patient, the dental
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mandible position should be re-evaluated and confirmed
for stability.
CONCLUSION
Class III malocclusion may be a difficult task in
orthodontic treatment, since we need to differentiate
Yang C, Tseng YC
63Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 110.30036/TJO.201903_31(1).0006
Anterior Cross Bite with Deep OB
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