Diagnosis and conservative treatment of skeletal

Diagnosis and conservative treatment of skeletal
Class III malocclusion with anterior crossbite and
asymmetric maxillary crowding
Linda L. Y. Tseng,a
Chris H. Chang,b
and W. Eugene Robertsc
Hsinchu, Taiwan, Indianapolis, Ind, and Loma Linda, Calif
A man, aged 28 years 9 months, came for an orthodontic consultation for a skeletal Class III malocclusion
(ANB angle, À3
) with a modest asymmetric Class II and Class III molar relationship, complicated by an anterior
crossbite, a deepbite, and 12 mm of asymmetric maxillary crowding. Despite the severity of the malocclusion
(Discrepancy Index, 37), the patient desired noninvasive camouflage treatment. The 3-Ring diagnosis showed
that treatment without extractions or orthognathic surgery was a viable approach. Arch length analysis indicated
that differential interproximal enamel reduction could resolve the crowding and midline discrepancy, but a
miniscrew in the infrazygomatic crest was needed to retract the right buccal segment. The patient accepted
the complex, staged treatment plan with the understanding that it would require about 3.5 years. Fixed appliance
treatment with passive self-ligating brackets, early light short elastics, bite turbos, interproximal enamel
reduction, and infrazygomatic crest retraction opened the vertical dimension of the occlusion, improved the
ANB angle by 2
, and achieved excellent alignment, as evidenced by a Cast Radiograph Evaluation score of
28 and a Pink and White dental esthetic score of 3. (Am J Orthod Dentofacial Orthop 2016;149:555-66)
A
n Angle classification for malocclusion focuses
on the occlusal relationship of the first molars,
so it can be misleading for many malocclusions.1
Likewise, anterior crossbites may be deceptive, particu-
larly when associated with a prognathic skeletal pattern
and a concave face. This unusual case appears to be a
modest problem based on the molar discrepancy, but it
is a severe malocclusion based on the American Board
of Orthodontics Discrepancy Index score of 37, as shown
in Supplementary Worksheet 1. Furthermore, the face,
anterior crossbite, and ANB angle of À3
are consistent
with a skeletal Class III malocclusion. Despite the severity
of the problem, the patient insisted on the most
conservative treatment possible, so a careful differential
diagnosis was critical to determine whether a relatively
noninvasive approach was indicated or even possible.
Anterior crossbites with a Class III skeletal pattern
have a layer of complexity that is not readily diagnosed
unless a systematic test is used such as Lin's 3-Ring
diagnosis method.2,3
A careful application of the
Discrepancy Index and the 3-Ring method demonstrated
that conservative treatment was feasible. However,
optimal sagittal alignment of the dentition required a
stainless steel miniscrew (OrthoBoneScrew; Newton's
A, Hsinchu, Taiwan) in the right infrazygomatic crest
to retract the right buccal segment.
DIAGNOSIS AND ETIOLOGY
A man, aged 28 years 9 months, came for an
orthodontic consultation with the following chief
concerns: thin upper lip, irregular dentition, and poor
smile esthetics (Fig 1). There was no contributing
medical or dental history. The clinical examination
showed a retrusive upper lip, a deep anterior crossbite
of all maxillary incisors, a posterior lingual crossbite of
the maxillary right second premolar, and irregular dental
attrition of the maxillary right central incisor. Overbite
was 7 mm, and overjet was À3 mm. There were
12 mm of asymmetric crowding in the maxillary arch,
and asymmetric Class II (right) and Class III (left) buccal
segments associated with a midline deviation of the
a
Lecturer, Beethoven Orthodontic Center, Hsinchu, Taiwan.
b
Director, Beethoven Orthodontic Center, Hsinchu, Taiwan.
c
Professor emeritus, School of Dentistry, Indiana University; adjunct professor,
School of Mechanical Engineering, Indiana University and Purdue University at
Indianapolis, Indianapolis, Ind; visiting professor, Department of Orthodontics,
School of Dentistry, Loma Linda University, Loma Linda, Calif.
All authors have completed and submitted the ICMJE Form for Disclosure of
Potential Conflicts of Interest, and none were reported.
Address correspondence to: W. Eugene Roberts, Indiana University, School of
Dentistry, 1121 W. Michigan St, Indianapolis, IN 46202; e-mail, werobert@iu.
edu.
Submitted, November 2014; revised and accepted, April 2015.
0889-5406/$36.00
Copyright Ó 2016 by the American Association of Orthodontists.
http://dx.doi.org/10.1016/j.ajodo.2015.04.042
555
CASE REPORT

maxilla that was 3 mm to the right (Fig 2). The radio-
graphic and cephalometric surveys before treatment
are shown (Fig 3). The cephalometric measurements
are summarized in Table I. A severely worn facet on
the maxillary right central incisor required coordinated
orthodontic alignment and restorative care (Fig 4).
TREATMENT OBJECTIVES
In the maxilla (all 3 planes), the objective was to
maintain the anteroposterior, vertical, and transverse
relationships.
In the mandible (all 3 planes), the objectives were
to maintain the anteroposterior and transverse relation-
ships and to rotate the vertical segment clockwise to
improve the ANB angle.
For the maxillary dentition, the objectives were to
(1) protract the incisors and retract the molars
anteroposteriorly, (2) slightly increase the vertical, and
(3) slightly increase the intermolar width.
For the mandibular dentition, the objectives were to
(1) retract anteroposteriorly; (2) intrude the incisors verti-
cally, and (3) maintain intermolar and intercanine widths.
For the facial esthetics, the objectives were to
(1) increase the upper lip protrusion and (2) increase
the vertical dimension of the occlusion to achieve an
orthognathic proﬁle.
TREATMENT ALTERNATIVES
After a careful evaluation of the patient's problems,
we proposed 3 tentative treatment plans. Treatment
Fig 1. Pretreatment facial and intraoral photographs.
556 Tseng, Chang, and Roberts
April 2016 Vol 149 Issue 4 American Journal of Orthodontics and Dentofacial Orthopedics

Fig 2. Pretreatment study models.
Fig 3. Pretreatment panoramic radiograph, lateral cephalometric radiograph, and cephalometric
tracing, showing a protruded lower lip and crowding of the maxillary arch.
Tseng, Chang, and Roberts 557
American Journal of Orthodontics and Dentofacial Orthopedics April 2016 Vol 149 Issue 4

plan A was extraction of the maxillary second premolars
and the mandibular first premolars. Treatment plan B
was insertion of 2 miniscrews in the buccal shelf of the
mandible to retract the entire arch. Treatment plan C
was nonextraction camouflage treatment using Class
III elastics to retract the mandibular labial segment
and protract the maxillary labial segment. The patient
chose the most conservative option: treatment plan C.
However, this relatively noninvasive approach required
extensive interproximal reduction of the anterior
maxillary arch and an orthodontic bone screw in the
infrazygomatic crest to retract the right buccal segment.
The patient was informed that this conservative
approach would require 3 to 4 years of treatment,
primarily because of the sequence of procedures
necessary to resolve 12 mm of asymmetric crowding in
the maxillary arch, without extracting any teeth. He
accepted this treatment limitation.
The final plan included the following: (1) no extrac-
tions or orthognathic surgery; (2) Damon Q brackets
(Ormco, Glendora, Calif): standard torque passive
self-ligating brackets bonded upside-down on the
maxillary canines, lateral incisors, and central
incisors to resist the flaring effect of Class III elastics;
(3) open-coil springs between the maxillary right first
molar and first premolar, and between the maxillary
right canine and central incisor for opening space to
relieve crowding; (4) bite turbos on the mandibular
canines initially and then on the mandibular central
incisors as the bite opened; (5) Class III early light short
elastics to assist with anterior crossbite correction and to
open the vertical dimension of the occlusion; (6) an
OrthoBoneScrew in the right infrazygomatic crest to
retract the right buccal segment; and (7) restoration of
the maxillary right central incisor with a porcelain veneer
or composite resin.
TREATMENT PROGRESS
The 0.022-in slot Damon Q standard torque
brackets were bonded on the mandibular arch. Bite tur-
bos were bonded on the lingual surfaces of mandibular
canines to open the bite and facilitate anterior crossbite
correction (Fig 5). One month later, the maxillary arch
was bonded with standard torque brackets, but those
on the 6 maxillary anterior teeth (canine to canine)
were bonded upside-down to deliver negative torque
(Table II). Initially, there was inadequate space to
bond the maxillary right second premolar and the
lateral incisor, so open-coil springs were placed on
the archwire, and those teeth were bonded with
upside-down, standard torque brackets as soon as
adequate space was available. The lengths of the
active nickel-titanium springs were extended approxi-
mately 2 mm to activate space opening. The maxillary
right central incisor was severely worn, with dentin
exposure. The amount of lost tooth structure was
estimated to be about 2 mm in the axial dimension,
so the bracket position for the maxillary left central
incisor was 6 mm from the incisor edge, and the corre-
sponding distance for the maxillary right central incisor
was only 4 mm (Fig 6). The goal was to achieve optimal
gingival alignment and then restore the maxillary right
central incisor tooth structure as needed. The initial
archwires were 0.014-in copper-nickel-titanium. Class
III early light short elastics (Quail, 3/16-in, 2 oz; Ormco)
were placed from the mandibular first premolars to the
maxillary first molars, and bite turbos were bonded on
the lingual surfaces of the mandibular central incisors
(Fig 7). The stepwise opening of the bite with bite tur-
bos was for patient comfort. The patient was instructed
to wear the 2-oz early light short elastics full time and
to replace them with new ones at least 4 times per day,
preferably after meals or snacks. By the fifth month of
Table I. Cephalometric measurements
Pretreatment Posttreatment Difference
Skeletal
SNA (
) 81 81 0
SNB (
) 84 82 2
ANB (
) À3 À1 2
SN-MP (
) 28 29 1
FMA (
) 23 24 1
Dental
U1 to NA (mm) 3 7 4
U1 to SN (
) 102 114.5 12.5
L1 to NB (mm) 3 3 0
L1 TO MP (
) 88 91.5 3.5
Facial
E-line to UL (mm) À5 À4 1
E-line to LL (mm) À0.5 À2 1.5
U1, Maxillary incisor; L1, mandibular incisor; UL, upper lip; LL,
lower lip.
Fig 4. A severely worn facet along the incisal surface of
the maxillary right central incisor had dentin exposure.

treatment, the anterior crossbite was corrected (Fig 8),
the bite turbos were removed, and the mandibular
archwire was changed to 0.014 3 0.025-in copper-
nickel-titanium. In the seventh month, the maxillary
archwire was changed to 0.014 3 0.025-in copper-
nickel-titanium. Drop-in hooks (Ormco) were fitted
into the vertical slots of the maxillary canine brackets
to secure the Class II elastics (Fox, 1/4-in, 3.5 oz;
Ormco), which accomplished anteroposterior correction
while promoting development of the smile arc. The
change from Class III to Class II elastics at 7 months
(Fig 7) was necessary because of the opening of the
bite and the 2
improvement in the ANB angle.
In the eighth month, the open-coil springs were
reactivated with a light-cured resin ball or a crimpable
stop (Fig 9, A and B). In the tenth month, the mandibular
anterior teeth were too lingually inclined, so the archwire
was changed to a 0.016 3 0.025-in nickel-titanium,
pretorqued with 20
of lingual root torque. In the 15th
month of active treatment, the maxillary archwire was
replaced by a 0.017 3 0.025-in beta-titanium alloy
(Ormco). By 18 months, there was still inadequate space
to align the maxillary right second premolar (Fig 9, C),
and additional coil spring activation was indicated. In
the 21st month, OrthoBoneScrews were inserted at the
right infrazygomatic crest, and an elastomeric chain
was attached to retract the maxillary right canine
(Fig 10). Three months later (at 24 months of treatment),
no significant space opening to align the maxillary right
second premolar had been achieved. In the 25th month
of the treatment, interproximal reduction was performed
on the 4 maxillary incisors and along the mesial aspect of
the maxillary right first molar (Fig 11). Then 5 teeth—
maxillary right canine to maxillary lateral incisor—were
tied together with a power tube. In the 27th month, space
Fig 5. Bite turbos on the lingual sides of the mandibular canines were used to disarticulate the occlu-
sion (open the bite). Bite turbos for the mandibular incisors were made with a BT Mold (Newton's A) for a
5-mm bite ramp bonder (maxillary). The mold (bonder) is filled with composite resin, positioned against
the lingual surface of the tooth, and then cured with light (mandibular).
Table II. DamonQ torque brackets are available in
high, standard, and low torque for both arches
Torque
Maxillary arch (
) Mandibular arch (
)
U1 U2 U3 L1 L2 L3
High 22 13 11 11 11 13
Standard 15 6 7 À3 À3 7
Low 2 À5 À9 À11 À11 0
Standard upside-down À15 À6 À7
For the maxillary arch (U1, U2, and U3), the bracket can be placed
upside-down to deliver superlow torque.
U, Maxillary; L, mandibular.
Fig 6. A, Two open-coil springs were inserted on the right
side to create space for the maxillary second premolar
and lateral incisor. B, Standard torque brackets were
bonded upside-down from canine to canine in the upper
arch in the maxillary anterior segment. Note that the
bracket position for the maxillary right central incisor
(arrow) is at the same level as the adjacent central incisor
relative to the gingival margin.

opened on the mesial side of the right second premolar.
In the 28th month, a button was bonded to the right
second premolar, and an elastomeric chain was used
for buccal traction to align it; in the 32nd month,
it was engaged on a 0.014-in nickel-titanium archwire
(Fig 12). At 38 months of treatment, it was finally
aligned. Two weeks before the completion of active
treatment, the maxillary archwire was sectioned distally
to the canines, and box elastics (Fox 1/4 in, 3.5 oz)
were used to improve the occlusal contacts. After
42 months (3.5 years as projected) of active treatment,
all appliances were removed, and 2 retainers were
delivered: a maxillary clear overlay and a maxillary
anterior 2-2 fixed.
TREATMENT RESULTS
In the maxilla (all 3 planes), the anteroposterior,
vertical, and transverse relationships were maintained.
In the mandible (all 3 planes), the anteroposterior and
transverse relationships were maintained, and clockwise
rotation increased the vertical dimensions of the
occlusion and the ANB angle.
In the maxillary dentition, the following results were
obtained: (1) anteroposteriorly, the incisors were flared
Fig 7. A, Attachment of Class III early light short elastics (arrow) between the maxillary right first molar
and the mandibular right first premolar (Quail, 3/16 in, 2 oz). B, Attachment of Class III early light short
elastics (arrow) between the maxillary left first molar and the mandibular left first premolar. Note that the
maxillary left central incisor bites on the bite turbo. C, Bite turbos (arrow) bonded at the lingual surfaces
of the mandibular anterior teeth prevent bracket interference while correcting the crossbite.
Fig 8. In the fifth month of treatment, the anterior cross-
bite was corrected, so the anterior bite turbos were
removed. At the same appointment, the mandibular arch-
wire was changed to a 0.014 3 0.025-in copper-nickel-
titanium wire.
Fig 9. A, The open-coil spring was reactivated by adding
a light-cured resin ball. B, The open-coil spring was reac-
tivated by installing a crimpable stop mesial to the maxil-
lary first molar. C, At 18 months of treatment, there was
still inadequate space to align the maxillary right second
premolar.
Fig 10. At 21 months, an OrthoBoneScrew (Newton's A)
was placed in the right infrazygomatic crest, and a power
chain was attached from the maxillary right canine to the
OrthoBoneScrew to retract the right buccal segment as
the space was opened for the maxillary right second pre-
molar. At 24 months, no space was gained to align the
maxillary right second premolar.

(102
to 114.5
); (2) the molars were retracted and
extruded vertically; and (3) the intermolar and interca-
nine widths were maintained.
In the mandibular dentition, the anteroposterior and
the intermolar and intercanine widths were maintained,
and vertically, the incisors were intruded and the molars
were extruded.
For the facial esthetics, a facial profile with normal
convexity was obtained.
Retention
A fixed retainer was bonded on all maxillary incisors.
A clear overlay retainer was delivered for the maxillary
arch, and the patient was instructed to wear it full
time for the first 6 months and only at night thereafter.
Instructions were provided for oral hygiene and mainte-
nance of the retainers.
Final evaluation of treatment
The facial profile was improved primarily by
increasing the relative prominence of the upper lip and
increasing the vertical dimension of occlusion (Fig 13).
Both arches were well aligned and optimally interdigi-
tated in a near-ideal Class I occlusion, with coincident
dental midlines (Fig 14). Comparing the pretreatment
and posttreatment cephalometric tracings shows that
the SN to mandibular plane angle increased by 1
because of the clockwise rotation of the mandible
(Fig 15). The axial inclination of the maxillary incisors
to SN increased from 102
to 114.5
(Table I). The
mandibular incisors were intruded, but all molars were
extruded (Fig 16). The Cast Radiograph Evaluation score
was 28 points, as shown in Supplementary Worksheet 2.
Most of the points deducted were for lack of occlusal
contacts (8 points). Dental esthetics were excellent as
documented by the Pink and White dental esthetic index
of 3, shown in Supplementary Worksheet 3. Although
the conservative plan required 3.5 years of active
treatment, the patient was pleased with the results.
DISCUSSION
Conservative treatment of a Class III skeletal
malocclusion is popular with patients but challenging
for orthodontists. There are 4 principal factors
contributing to successful conservative management:
accurate diagnosis, advanced fixed appliances, custom
auxiliaries, and interproximal enamel reduction.2,3
After determining the complexity of a malocclusion
with the Discrepancy Index, a realistic diagnosis and
treatment plan are facilitated by 2 stepwise differential
tests: the 3-Ring diagnosis system (Fig 17) and the
Extraction Decision Table (Table III).
A skeletal Class III malocclusion is often confused
with pseudo-Class III problems, which typically have a
functional shift or an anterior crossbite with Class I
buccal segments.4
Lin5
reported that the prevalence of
skeletal Class III malocclusion is about 1.65% in Taiwan,
Fig 12. A, After 30 months, a button was bonded on the
buccal surface of the maxillary right second premolar,
and an elastic chain was attached. It was activated by
attaching the opposite end to the infrazygomatic crest
miniscrew. B, At 36 months, a bracket was bonded on
the buccal surface of the maxillary right second premolar,
and it was engaged on a 0.014-in copper-nickel-titanium
archwire. C, At 38 months, the maxillary right second
premolar was aligned, and a 0.017 3 0.025-in beta
titanium alloy archwire was engaged.
Fig 11. A, At 25 months, space was opened between the maxillary central incisors with an abrasive
strip. B, A tapered diamond bur was used to reduce the mesial surfaces of the maxillary central incisors.
C, The mesial surface of the maxillary right first molar was reduced in a similar manner.

but pseudo-Class III problems (Class I with anterior
crossbite) are found in approximately 2.31% of children
9 to 15 years of age. The 3-Ring diagnosis method
(Fig 17) was developed to help predict the prognosis
for anterior crossbite correction.6
The clinical data
showed that 90% of anterior crossbite corrections were
stable if the following diagnostic criteria were met:
(1) an acceptable facial profile in centric relation;
(2) the canines and molars in or near a Class I
relationship; and (3) an evident functional shift.
Good candidates for conservative (camouflage)
treatment have an orthognathic profile (acceptable facial
balance) in centric relation, buccal segments that are
approximately Class I, and a functional shift.7
There
were other favorable indicators: a marginally low to
average mandibular plane angle and no open bite.
Orthodontic camouflage to treat a Class III malocclusion
may result in increased axial inclination of the maxillary
incisors and decreased axial inclination of the mandibular
incisors, particularly if there is an underlying Class III
skeletal discrepancy.8
If it is necessary to retract the
mandibular incisors, an axial inclination of at least 88
is
desirable.9
The Extraction Decision Table of Chang10
(Table III)
was used to assess the necessity for extractions. The 2
factors favoring extraction were the protrusive profile
and crowding greater than 7 mm in the maxillary arch.
However, maxillary extractions would have complicated
the correction of the anterior crossbite and might result
in a midface deficiency. Furthermore, the patient was
Fig 13. Posttreatment facial and intraoral photographs.

Fig 14. Posttreatment study models (casts).
Fig 15. Posttreatment panoramic radiograph, lateral cephalometric radiograph, and cephalometric
tracing, showing the improved proﬁle and the parallel alignment of all tooth roots.

strongly opposed to extractions, so the nonextraction
option was selected, with the understanding that
extensive interproximal reduction and infrazygomatic
crest anchorage were necessary.
Passive self-ligating brackets with light wires
facilitate the conservative correction of Class III
malocclusions.7
The bracket is a tube-like appliance
capable of delivering a continuous light force, similar
to the multiloop edgewise archwire effect.7,11,12
If a
patient meets the 3 criteria of the 3-Ring diagnosis,
straight wires and Class III elastics are usually sufficient
to correct the malocclusion.2
For our patient, Class III
early light short elastics were used initially with bite
turbos but were then replaced by Class II elastics as
soon as the bite opened and the anterior crossbite was
corrected. These are common mechanics for patients
with an anterior crossbite and Class I buccal segments.
If it is necessary to manage an asymmetry or retract
the entire mandibular arch, bilateral buccal shelf
OrthoBoneScrews are indicated.7,12,13
Proper torque control with passive self-ligating
brackets and light nickel-titanium wires can be chal-
lenging.14
For this patient, the dental axial inclinations
were managed with low-torque brackets (Table II), pre-
torqued archwires, and temporary skeletal anchorage
devices to retract the right buccal segment. Controlling
torque with the selection of brackets is particularly
effective with passive self-ligating brackets15,16
(Table II). Low torque was used on the maxillary incisors
to compensate for the side effects of the Class III elastics:
flaring of the maxillary incisors and excessive retraction
of the mandibular incisors.17
If low-torque brackets are
insufficient for controlling axial inclinations, bonding
standard-torque brackets upside-down is a viable
alternative.15-17
If a rectangular archwire fails to
generate adequate root torque, a 20
pretorqued
archwire such as 0.016 3 0.025 in or 0.019 3 0.025
in is recommended. Since this patient had standard-
torque brackets bonded on the mandibular teeth, a
0.016 3 0.025-in nickel-titanium archwire with 20
of
torque was inserted 10 months into treatment to correct
the axial inclinations in the anterior segment.17
This problem could have been prevented by using
higher-torque brackets in the mandibular anterior
segment initially (Table II).
Correction of a deepbite can be achieved by molar
extrusion, incisor intrusion, or both. This patient's
deepbite was corrected with anterior bite turbos, which
intruded the mandibular incisors and allowed the
posterior segments to extrude (Fig 16). The advantages
of anterior bite turbos at the beginning of treatment
were to serve as vertical stops for the deep overbite, to
Fig 16. Initial (black) and final (red) cephalometric tracings are superimposed on the anterior cranial
base (left), and on the stable skeletal structures of the maxilla (upper right), and the mandible (lower
right).

unlock the posterior interdigitation, and to allow the
malocclusion greater freedom for 3-dimensional tooth
movement.15-17
Bite turbos for Class III treatment have
additional advantages: (1) protect the enamel from
attrition, (2) prevent accidental bracket debonding,
(3) improve the effect of light wires for 3-dimensional
tooth movement such as correction of posterior
crossbites, (4) improve the response to early light short
elastics, and (5) help correct mandibular plane angle
problems.15
For deep anterior crossbites, a stepwise
opening of the bite with bite turbos is more comfortable
for the patient (Figs 5 and 7).
For our patient, the anterior crossbite and deepbite
were corrected simultaneously in about 5 months using
Class III elastics as the principal active mechanics.15-17
Starting with 2-oz early light short elastics during the
leveling phase enhanced treatment efficiency by helping
to level the arches and achieve correction in the sagittal
plane.14,15
The side effects of Class III elastics are labial
tipping of the maxillary incisors, extrusion of the
maxillary molars, and distal tipping of the mandibular
molars.15-17
Since these effects were considered
favorable for our patient, Class III elastics were used
rather than inserting bone screws into the buccal shelf
of the mandible.12
At 21 months, an OrthoBoneScrew was placed at the
right infrazygomatic crest to provide anchorage to retract
the canine, prevent incisor flaring, and retract the molars.
However, these mechanics failed to open adequate space
for alignment of the maxillary right second premolar
(Fig 10). So, interproximal reduction was performed
with an air rotor and abrasive finishing strips in the
anterior segment of the maxillary arch to reduce the
black triangles, gain space for alignment of the
maxillary right second premolar, improve tooth
proportions, and establish more ideal interproximal
contacts (Fig 11).18,19
The Pink and White esthetic score evaluates anterior
maxillary esthetics by analyzing clinical photographs.
Refer to the scoring form in Supplementary Worksheet
3. The form includes 2 esthetic assessments: Pink is a
gingival evaluation, and White is a score of dental
microesthetics. The column on the right lists 6 variables
that are scored from 0 to 2 for each assessment. The
actual Pink and White score is marked with red circles
for the 6 variables in the areas highlighted in blue.20
The deficiencies scored were blunted mesial and distal
gingiva papillae, creating small dark triangles between
the incisors; inadequate incisal curve (smile line); and
an apparent deviation from the ideal incisal root
angulation. Three points or fewer on the Pink and White
score is considered an excellent result, particularly for
patients with incisal abrasion.
The anterior cranial base superimposition (Fig 16)
shows that the mandible was rotated posteriorly
approximately 4 mm, but the Frankfort-mandibular
plane angle opened by only 1
because the posterior
mandible moved inferiorly. This unusual pattern of
mandibular rotation may indicate a morphologic
problem in the temporomandibular joints. In retrospect,
it might have been wise to use a cone-beam computed
tomography image prospectively to evaluate the joints.
Furthermore, a cone-beam image might be a wise
precaution for assessing all skeletal malocclusions that
require surgery or temporary anchorage devices.
Fig 17. The Class III diagnosis system developed by Lin6
has simplified the complicated diagnostic procedure for
assessing anterior crossbite.
Table III. The Extraction Decision Table of Chang,10
summarizing the aids for determining an extraction
or nonextraction treatment plan
Extraction Nonextraction
1. Profile Protrusive Straight
2. Mandibular angle High Low
3. Bite Open Deep
4. Anterior inclination Flaring Flat
5. Crowding .7 mm None
6. Decayed or missing teeth Present ?
7. Patient perception OK No

CONCLUSIONS
This difficult skeletal malocclusion (ANB angle, À3
;
Discrepancy Index, 37) was treated to an excellent result
(Cast Radiograph Evaluation, 28) without extractions or
orthognathic surgery. A differential diagnosis using 3
methods (Discrepancy Index, 3-Ring, and Extraction
Decision Table) showed that the patient's desire for
conservative treatment was feasible. A carefully
sequenced treatment plan achieved an excellent result
for this severe malocclusion, but it did require 3.5 years
of treatment. In retrospect, the treatment time might
have been decreased by introducing interproximal
reduction and infrazygomatic crest anchorage earlier
in the sequence, but the necessity for those more-
invasive measures was not clear until about 18 months
into treatment. Despite 12 mm of asymmetric crowding
in the maxillary arch, the problem was treated to an
optimal result without excessive arch expansion and
incisal flaring.21
ACKNOWLEDGMENTS
We thank Paul Head for proofreading this article.
SUPPLEMENTARY DATA
Supplementary data related to this article can be found
at http://dx.doi.org/10.1016/j.ajodo.2015.04.042.
REFERENCES
1. Angle EH. Classification of malocclusion. Dent Cosmos 1899;41:
248-64.
2. Lin JJ. The most effective and simplest ways for treating severe
Class III without extraction or surgery. Int J Orthod Implantol
2014;33:4-18.
3. Yeh HY, Lin JJ, Roberts WE. Conservative adult treatment for
severe Class III openbite malocclusion with bimaxillary crowding.
Int J Orthod Implantol 2014;34:12-25.
4. Kelly J, Harvey C. An assessment of the teeth of youths 12-17
years:Publication No. (HRA) 74-1644. Washington, DC: National
Center for Health Statistics, US Public Health Service; 1977.
5. Lin JJ. Prevalence of malocclusion in Taiwan children age 9-15.
Clin Dent 1984;4:227-34.
6. Lin JJ. Creative orthodontics blending the Damon System TADs
to manage difficult malocclusion. 2nd ed. Taipei, Taiwan: Yong
Chieh; 2010. p. 263-71.
7. Lin JJ, Liaw JL, Chang HN, Roberts WE. Class III correction ortho-
dontics. Taipei, Taiwan: Yong Chieh; 2013. Published electroni-
cally on Apple iBooks as Orthodontics vol. 3: Class III correction.
8. Costa Pinho TM, Ustrell Torrent JM, Correia Pinto JG. Orthodon-
tics camouflage in the case of a skeletal Class III malocclusion.
World J Orthod 2004;5:213-23.
9. McLaughlin RP, Bennett JC, Trevisi H. Systemized orthodon-
tics treatment mechanics. London, United Kingdom: Mosby;
2001.
10. Chang CH. Advanced Damon course no.1: extraction
decision-making (table). Beethoven Podcast Encyclopedia in
Orthodontics. Hsinshu, Taiwan: Newton's A; 2011.
11. Pollard AP. Capturing the essence of the Damon approach. Clin
Impression 2003;12:4-11.
12. Lin JJ. Treatment of severe Class III with buccal shelf mini-screws.
News Trends Orthod 2010;18:3-12.
13. Huang S. Non-extraction management of skeletal class III
malocclusion with facial asymmetry. News Trends Orthod 2010;
20:22-31.
14. Kozlowski J. Honing Damon system mechanics for the ultimate in
efficiency and excellence. Clin Impressions 2008;16:23-8.
15. Pitts T. Begin with the end in mind: bracket placement and early
elastics protocols for smile arc protection. Clin Impressions
2009;17:4-13.
16. Huang S, Pitts T. Secrets of excellent finishing. News Trends
Orthod 2009;14:6-23.
17. Chang CH. Basic Damon course no. 5: finish bending. Beethoven
Podcast Encyclopedia in Orthodontics. Hsinshu, Taiwan: Newton's
A; 2012.
18. Zachrisson BU, Nyoygaard L, Mobarak K. Dental health assessed
more than 10 years after interproximal enamel reduction of
mandibular anterior teeth. Am J Orthod Dentofacial Orthop
2007;131:162-9.
19. Hsu YL. Approaching efficient finishing with hard and soft tissue
contouring, part II: hard tissue contouring. News Trends Orthod
2008;11:17-9.
20. Su B. IBOI Pink and White esthetic score. Int J Orthod Implantol
2012;28:80-5.
21. Liaw JL. Molar retraction in all four quadrants to correct a Class III,
crowded malocclusion in a patient with a flat profile. Int J Orthod
Implantol 2012;27:20-31.

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