2. INTRODUCTION
The bone anchors are used to increase orthodontic
anchorage in the anterior or posterior region of the
upper and/or lower jaw. A 2 or 3 holes titanium mini
plate is fixed by monocortical mini screws. The SAS is
comprised of bone plates and fixation screws. The plates
and screws are made of commercially pure titanium that
is biocompatible and suitable for
osseointegration. The anchor plate
consists of the three components, the
head, the arm, and the body.
3. The head component is exposed intraorally and
positioned outside of the dentition so that it does not
interfere with tooth movement. The head component has
three continuous hooks for attachment of orthodontic
forces. There are two different types of head components
based on the direction of the hooks.
4. . The arm component is transmucosal and is available in
three different lengths—short (10.5 mm), medium (13.5
mm), and long (16.5 mm) to accommodate individual
morphological differences
5. ORTHODONTIC INDICATIONS
1 Distal movement of the anterior segment in premolar
extraction cases.
2. Distal movement of the posterior and anterior
segment in non-extraction cases.
3. Mesial movement of posterior teeth.
4. Intrusion of a single tooth or a group of teeth.
5. Uprighting of mesialised lower second and third
molars.
6. Loss of dental anchorage because of periodontal
diseases.
7. Orthopaedic intermaxillary tractions.
10. The zygomatic buttress and the canine region of the
mandible are the anatomical sites recommended for the
majority of the orthodontic applications.
11. SURGICAL METHOD FOR IMPLANT PLACEMENT
Incision is the most important part of the surgical
procedure. The correct location of the incision is
decided by digital palpation. By using the index finger,
the zygomatic buttress is palpated, and the incision is
made along the buttress in a vertical or horizontal
direction. In vertical direction, the lower border of the
incision is at the intersection of the attached and the
mobile gingiva, and the total length is no longer than 1
cm.
12. STEP-BY-STEP PROCEDURE
In the maxilla an L-shaped incision is made with
anterior convexity. The vertical part of the incision (1) is
made ± 1 cm mesial from and parallel to the infra-
zygomatic crest and up to 2 mm below the muco-
gingival boarder. The incision is extended distally (2)
with a horizontal incision 2 mm below and parallel to
the muco-gingival boarder.
13.
14. The mini plate is slightly bended to obtain good contact
to the cortical bone. The bending should be limited to
the region between the holes in the mini plate. The
connection between the mini plate and the neck should
be slightly bended in the opposite direction to ensure
good contact between the lower part of the neck and the
alveolar bone.
15.
16. The first screw is not completely fixed in order to
allow some rotation of the mini plate. The lower
hole is drilled and the mini screw is inserted,
followed by the upper one and all are fixed for a
strong stable retention.
17.
18.
19. After rinsing with saline solution, closure is obtained
with elf resorbing sutures. The mucoperioteal flap is
positioned by the first suture just anterior from the neck
of the bone anchor. Additional sutures are placed until
good closure is obtained. The fixation unit should be
oriented parallel to the alveolar bone.
20. In the mandible a horizontal full thickness incision is
made into the gingival sulcus along the marginal bone
starting in front of the second premolar extending
mesially and including the distal papilla of the canine.
Just before the lowest point of the gingival margin in
front of the canine the incision is continued vertically
and slightly forward.
21. The bone anchor is positioned parallel to and between
the roots of the canine and the first premolar. The neck
should penetrate the soft tissues exactly at the level of
the vertical incision and 2 mm above the muco-gingival
boarder throughout attached gingiva. The first hole is
drilled in the inter-radicular space between the canine
and first premolar at the level of the roots apices.
The first screw is inserted but not completely fixed to
allow some rotation of the mini plate. The second screw
is inserted in the mandibular body and both are fixed for
a strong stable retention.
22. After rinsing with saline solution, closure is obtained in
one or two planes with self resorbing sutures. Sutures are
placed through both papilla and along the vertical
incision.
23.
24. RECOMMENDATIONS FOR THE ORTHODONTIST
• To reduce the risk for infections the placement of the
bone anchor should never be combined with extractions
of teeth.
• Removal of the remaining stitches and oral hygiene
instruction with toothbrush 10 days after surgery.
• Continuous orthodontic lading is recommended 2
weeks after surgery. Therefore both arches should be
orthodonticaly leveled before the placement of the bone
anchor. The first month light forces are used.
25. • The orientation of the fixation unit can be slightly
changed by finger pressure. Local anaesthesia is not
needed.
• The bone anchor should be removed when there is no
more need for skeletal anchorage.
26. COMPLICATIONS
- Development of Inflammation
Inflammation may develop in any phase of treatment. In
such a case, if the implant is not mobile, force
application must be stopped and antibiotic treatment
started, supported with bactericidal mouthwash. The
healing period is about 15 days. Force application can be
restarted when healing is complete, provided the
implant is not mobile, which is unlikely.
27. - Soft Tissue Impingement on Palate
If the palatal bars are not constructed far enough from
the palate, they may impinge on the palatal mucosa
during later stages of the dentoalveolar impaction.
Bactericidal mouthwash may be used if the impaction is
completed and the appliance is to be removed. If
considerable impaction remains to be performed, the
appliance should be replaced.
28. PATIENT INSTRUCTIONS
• Ice application immediately after surgery to reduce
swelling of the soft tissues.
• Antiseptic mouth rinsing and gently brushing the
region of the bone anchor in the first week after surgery.
• Appointment with the orthodontist 10 days after
surgery to remove the remaining sutures and for
hygiene instruction.
• Appointment 2 weeks after surgery to start
orthodontic loading.
• The patient should not touch the bone anchor with his
tongue. These intermittent forces may be responsible for
the loosening of the bone anchor some weeks after
surgery.
30. An 11-year old Chinese boy in late mixed dentition,
Extraoral examination revealed that the maxilla was
retrognathic and the mandible was slightly prognathic.
Intraoral examination revealed an anterior and posterior
crossbite with a reverse overjet of 4 mm.
31. The molars were in class III relationship on both sides.
There was no crowding in both maxillary and
mandibular arches. Temporomandibular joint function
was normal.
Cephalometric analysis indicated a moderate skeletal
class III malocclusion due to both maxillary retrusion
and mandibular protrusion. The mandibular plane was
tilted 30° to S-N plane.
32.
33. Treatment plan
The patient and parents were concerned about
dentofacial appearance. Treatment option was to use a
facemask combined with fixed appliance to correct the
anterior and posterior crossbite and improve facial
esthetics.
The patient and parents were informed
that the treatment plan did not
eliminate the possibility of
orthognathic surgery later. The
unfavorable growth of the jaws
during or after treatment might
necessitate a surgical treatment
plan. The use of miniplate implant
as anchorage for maxillary protraction
was suggested and the patient and parents agreed.
34. Treatment progress
Miniplate implant placement
Titanium miniplates were implanted by an experienced
oral surgeon. After mouth rinsing for 3 minutes with
0.2% chlorhexidine gluconate, under local anesthesia, a
mucoperiosteal incision was made at the labial vestibule
between the upper lateral incisors and canines on both
sides.
Miniplates were placed on the lateral nasal wall of maxilla.
35. The mucoperiosteal flap was then elevated, and the
surface of the cortical bone at the apical region of lateral
incisors and canines was exposed. An appropriate length
of I-shaped miniplate (plate thickness 1 mm, 3 holes)
was selected and fixed in position with self-tapping
screws (diameter 2 mm, length 7 mm), with the head
exposed to the oral cavity from the incised wound.
36. Care was taken to adjust the angle between the head and
the body of the plates so that the head portion would not
apply pressure on the attached gingiva. The incisions
were finally closed and sutured with absorbable thread
around the miniplate. This patient showed mild facial
swelling for a week after the operation. It was necessary
to take antibiotics and brush carefully
37. Maxillary protraction appliance design
A month was allowed for healing before application of
force to the miniplates. After the month, the clinical
evaluation for the patient included an assessment of
plate mobility and infection. If nothing was abnormal,
maxillary protraction was started. First, thread a
segment of brass wire through the hole in the head of
miniplate. Second, a ganoid composite resin ball
(diameter 2−3 mm) was
made at top of brass wire.
The ball was used for
Protraction hook.
38. A protraction force of 450 g per side at first, 500−600 g
per side after one month with an anteroinferior force
vector 30° to the occlusal plane, was applied from the
composite ball in anchor miniplates to the facemask by
using elastic modules. The patient was instructed to
wear facemask at least 10 hours a day and prolong the
wearing time as much as possible.
39. Traction was continued for 6 months until enough
forward movement of the maxilla had been achieved to
improve the midface esthetics. After maxillary
protraction, the miniplate implant was removed
under local anesthesia, then fixed appliance was
bonded.
40. Treatment result
The application of protraction force from a facemask to a
miniplate resulted in a significant improvement in facial
esthetics and the maxillo-mandibular jaw relation.
SNA was changed from 79.89° to 82.53°, SNB
angle from 84.16° to 81.67°, ANB angle from −4.27° to
0.86°, Wits from −10.18 mm to −2.66 mm, A-NP distance
increased by 5.48 mm, mandibular
plane angle increased by 2°, while
the change of U1/SN was not
significant.
43. An 8-year-old girl with a chief concern of “my bite is not
right.”
Clinically, she had a concave facial profile, and acute
nasolabial angle, and a protrusive mandible.
44.
45. Intraorally, she had an anterior crossbite and a low
anterior tongue posture. The maxillary right first
deciduous molar and left second deciduous molar had
exfoliated prematurely, and midarch crowding was
noted on the dental casts and panoramic radiograph.
The cephalometric radiograph and tracing showed
a skeletal Class III malocclusion with maxillary
deficiency, mandibular prognathism (ANB, –2.2), and
a normal mandibular plane angle (FMA, 23).
46. The maxillary incisors were proclined (U1 to FH, 109),
and the mandibular incisors were retroclined (IMPA, 86),
compensating for the skeletal malocclusion. There was
no family history of mandibular prognathism.
47. TREATMENT PROGRESS
Phase 1 treatment was started at age 8 years 4
months with a maxillary removable appliance to regain
space lost from the early loss of the deciduous molars.
After 6 months of observation, a surgical miniplate was
placed. Local infiltration anesthesia was administered to
the maxillary left and right buccal vestibular areas after
surgical disinfection.
48. A vestibular incision around the canine area was
performed. After an atraumatic subperiosteal dissection
to the infrazygomatic crest, a curvilinear miniplate was
adapted, bent to the zygomatic buttress’s bony surface,
and fixated with 3 self-tapping miniscrews per side.
49. At least 3 to 4 screws should be placed to resist the
maxillary protraction force of about 300 to 400 cN per
side. Screw placement should be in a posteriorsuperior
direction to prevent damage to the premolar tooth
follicles. The end of the miniplate entered the oral cavity
between the canine and first premolar area in the
keratinized attached gingiva to prevent gingival
irritation. The oral portion of the miniplate was modified
into a hook for elastic
traction.
50. Maxillary protraction was started 2 weeks after
placement of the miniplates, with a force of 300cN per
side applied 12 to 14 hours per day. Within 10 months
of treatment, a three quarters premolar width Class II
molar relationship was established. Thereafter, the
patient’s wearing of protraction headgear was limited
to nighttime only as a retainer for 10 months. The plates
were removed after the facemask
treatment.
51. A mucoperiosteal incision and a subperiosteal dissection
were performed to expose the miniplate. The
monocortical screws were removed first, and the
miniplate was then detached because often new bone is
deposited next to the plate. The surgical site was then
closed and sutured.
Progress records taken at age 10 years 7 months showed
favorable growth between the maxilla and the mandible,
and the malocclusion could be camouflaged by
orthodontic treatment.
52. The patient was treated with fixed appliances for 18
months to establish a good molar relationship and
correct the midline discrepancy. A maxillary
circumferential retainer and a mandibular lingual fixed
retainer were placed after appliance removal. The
patient was instructed to wear the retainer at night for 10
to 12 hours.
53. TREATMENT RESULTS
14 months after protraction headgear treatment. The
malocclusion was overcorrected to a Class II molar
relationship to compensate for future excessive
mandibular growth.
54.
55.
56. Superimposition of pretreatment and posttreatment
cephalometric tracings showed 8.1 mm of forward
movement of A-point (A-point to NtFH) and 3.3 of
counterclockwise tipping of the palatal plane .
The ANB angle changed from –2.2 to 1 6.7.
57. The SNO, or angle between the anterior cranial base and
orbitale, changed from 63 to 70. Labial tipping of the
maxillary incisors and lingual tipping of the mandibular
incisors, which are typically observed after tooth-borne
protraction, were not seen with the miniplates.
58. after phase 2 fixed appliance treatment at age 12 years 6
months. The ANB angle was reduced from 6.7 to 3.9,
indicating normalization of the jaw relationship after
overcorrection in the phase 1 treatment. Class I canine
and molar relationships were obtained, and overjet and
overbite were returned to normal after phase 2
treatment.
Intraoral photographs near the end of phase 2 fixed appliance
treatment.
59. - patient at age 14 years 9 months, 27 months after the
removal of the orthodontic appliances. During the
retention period, the maxilla and the mandible showed
relatively harmonious growth, maintaining an ANB
difference of 3. The angle of convexity was reduced from
7.4 to 5.4.
60.
61.
62. Superimposition of the posttreatment and postretention
cephalometric tracings showed continuous dental
compensation to the skeletal discrepancy was observed
with proclination of the maxillary incisors and slight
retroclination of the mandibular incisors.
63.
64. Orthopedic Traction of the Maxilla With
Miniplates: A New Perspective for
Treatment of Midface Deficiency
J Oral Maxillofac Surg 67:2123-2129, 2009
65. Summary of Cases and Diagnosis
Three girls (aged 10 to 11 years) presenting with a
severe skeletal Class III relationship with a maxillary
deficiency and concave soft tissue profile were treated
according to the same treatment plan. Two of them had
an anterior crossbite without anterior shift of the
mandible (cases 2 and 3). One had an edge-to-edge
incisor occlusion in centric relation, with a forward
posture into maximum intercuspation (case 1).
66.
67. Pretreatment cephalometric evaluation of the 3 cases
showed a skeletal Class III relationship with hypoplasia
of the maxilla combined with a normal or increased
mandibular size and normal or slightly decreased
vertical dimensions. The patients’ upper incisors were
proclined or retroclined, and the lower incisors were
normal or proclined.
68.
69. Treatment Plan
The 3 patients were treated exclusively by intermaxillary
traction between miniplates placed in the
maxilla and in the mandible, in combination with a
bite plane to jump the crossbite.
70. Treatment Progress
Four orthodontic miniplates were inserted into the
infrazygomatic crests and between the canine and lateral
incisor or between the canine and first premolar in the
mandible, on both the right and left sides. Surgery was
performed with patients under general anesthesia (cases
1 and 2) or local anesthesia (case 3). The miniplates were
fixed to the bone with 2 or 3 titanium screws (2.3 mm in
diameter and 5 mm in length) after predrilling with a
1.6-mm-diameter bur, as previously described.
71. Three weeks after surgery, maxillomandibular elastics
were attached between the upper and lower miniplates
on each side, applying a force of 100 g per side. The
patients were asked to replace the elastics once a day
and to wear them 24 hours per day. After 1 month (case
1) or 2 months (cases 2 and 3), a removable bite plane
was placed to eliminate the occlusal interference in the
incisor region. At this time, the elastic force was
increased to 200 g per side.
72. After 7 months (cases 1 and 2) or 12 months (case 3) of
orthopedic traction, the bite plane was removed. The
traction was maintained full time for a total period of 12
months (cases 1 and 2) or 16 months (case 3). No local
infections were observed around any of the miniplates.
They remained stable throughout treatment. During the
follow-up period after the active treatment, the patients
wore the elastics at night for retention.
73. Results
The anterior crossbite was corrected in each patient.
Their soft tissue profiles considerably improved, with
anterior displacement of the whole midface (infraorbital
ridge, nose, and upper lip), reducing the paranasal
concavity. Almost no anterior displacement of the lower
lip and chin was observed at the end of the traction,
leading to an improvement of the relationship between
the upper and lower lip. The tip of the nose moved
slightly upward.
74.
75.
76.
77.
78.
79. Lateral cephalograms were taken at the beginning
of treatment, at the end of orthopedic treatment, and
at follow-up 11 to 38 months later.
Cephalometric evaluation between the beginning
of treatment and end of treatment showed a marked
increase of ANB, Wits, and facial convexity (G=-Sn-
Pg=) values in all 3 cases . No rotation of the
mandible was observed in cases 1 and 3, whereas a
slight clockwise rotation was seen in case 2; there
was a slight counterclockwise rotation of the maxilla
in all patients. No major changes occurred in the
upper incisor inclination, whereas the lower incisors
were proclined. During the follow-up period (from
end of treatment to 11 to 38 months later), the Class
III correction was maintained.
83. The patient was an 11-year-old boy who was referred
for treatment of maxillary deficiency. He had no medical
problems, and there were no signs of
temporomandibular joint dysfunction. The patient had a
skeletal Class III malocclusion and maxillary deficiency.
His parents had no Class III characteristics.
84.
85. The facial photographs showed a Class III appearance
with a concave profile because of maxillary deficiency.
The pretreatment intraoral photographs and dental casts
showed Class III relationship of the central incisors and
anterior crossbite. The patient had a Class III molar
relationship on the right and Class I on the left side.
Cephalometric analysis confirmed the Class III skeletal
pattern.
Treatment Objectives
The treatment objectives for this patient were to
(1) correct the deficient maxillary arch, ideally by
forward
positioning of the maxilla;
(2) obtain an ideal overjet and overbite;
(3) correct the anterior crossbites.
86. Treatment Alternatives
Extraoral appliances, such as protraction facemask, Class
III functional appliance, any modified maxillary
protraction devices, and orthognathic surgery, were
considered as alternative treatments for the correction of
this Class III malocclusion. However, the patient refused
the use of extraoral appliances and major surgery.
Therefore, in this case, it was decided to use miniplates
to protract the maxilla by application of Class III elastics.
87. Treatment Progress
Plates for Orthodontic Anchorage were placed under
local anaesthesia in the canine areas of the mandible by a
maxillofacial surgeon. The ideal position for miniplates
insertion was evaluated by using a panoramic
radiograph in order to avoid damage to the roots of the
adjacent teeth and mental foramen.
88. A tightly fitting and well-retained upper removable
appliance was fabricated with two Adams clasps on the
upper first permanent molars. Each of the Adams clasps
had a loop which was used for retaining the elastics. A
labial bow was also used on the anterior teeth for
retention. A maxillary posterior bite plate was used to
disclude the upper and lower jaws.
89. Orthodontic latex elastics (3/16 heavy size—Unitek
Elastics) were connected from the hooks of the
miniplates to the Adams clasps of the removable
appliance to generate approximately 500 g of anterior
retraction. The patient was instructed to wear the
appliance full-time except for eating, contact sports, and
tooth brushing; he was also told to change the elastics
every day. In order to retain these elastics, the Adams
clasps on the molars were bent to form loops.
90. Treatment Results
After 10 months of active treatment a positive overjet
and Class I buccal segments were achieved and the
anterior crossbite was corrected. The posttreatment
cephalometric radiograph tracing showed a favourable
increase of 5.1◦ and 4.4◦ in the SNA and ANB angles,
respectively.
91. The pre- and posttreatment cephalometric
superimposition on the anterior cranial base is shown in
this Figure.
95. Bong-Kuen Cha and Peter W. Nga(2010)
Investigators have shown that maxillary protraction
with palatal expansion therapy is an effective method
for treatment of Class III patients.
Although intervention in the primary or early mixed
dentition may provide a better orthopedic response,
treatment started in the late mixed or early permanent
dentition can elicit reasonable orthopedic response when
the circummaxillary sutures are still patent.
96. One of the limitations in maxillary protraction with a
conventional tooth-borne type appliance is the loss of dental
anchorage, especially in the dynamic period of the mixed or
late permanent dentition.
Many investigators have attempted to design an absolute
anchorage system for maxillary protraction. A priori
ankylosed teeth, intentionally ankylosed maxillary
deciduous canines, or osseointegrated titanium implants
can be used as an absolute anchorage for protraction
treatment.
97. However, the use of ankylosed teeth limits the orthopedic
treatment to only the early mixed dentition period.
Skeletal anchorage by the use of miniscrews or
miniplates are gaining popularity as a source of absolute
anchorage in contemporary orthodontics.
Kuen Cha.B and Nagan.P quantified and compared the
effects of maxillary protraction using surgical miniplates
as anchorage to maxillary protraction in conjunction with
an expansion appliance (rapid maxillary expansion
[RME]).
98. Methods
Two treatment modalities for the correction of Class III
malocclusions in growing patients were compared by
treating 2 groups of patients. One group of 25 patients (16
girls and 9 boys) was treated with a facemask combined
with a bonded RME and a second group of 25 patients
(15 girls and 10 boys) treated with a facemask employing
a surgical miniplate as anchorage.
99. Schematic illustration shows a curvilineartype miniplate
fixed with 3 self-tapping miniscrews on the zygomatic
buttress area. The end of the miniplate was exposed between
the canine and first premolar area, located over the
keratinized attached gingiva to prevent gingival irritation.
Protraction force is approximately 300-400 gm per side and
the line of force is 30° to the occlusal plane.
100. The placement of miniplates was carried out under local
anesthesia.
The anchor plates were placed at the zygomatic buttress
area to avoid damage to the underlying developing tooth
buds of the permanent teeth
Protraction force is most often applied after 3 or 4
weeks of healing.
The facemask was inserted after maxillary expansion or
placement of the miniplate the total force applied was
400 g/side.
101. Patients in both treatment groups were instructed to
wear the appliance for at least 14-16 hours a day.
Posttreatment cephalometric radiographs were taken
when a normal dental relationship was obtained with
an overjet of 2-3 mm.
The average treatment time in miniplate group was 9.2 2.4
months and the RME group 8.5 2.4 months.
102. Pretreatment records of 11-
year, 4-month-old male
patient (THC) with Skeletal
Class III malocclusion and
anterior crossbite, crowding.
The concave profile is
shown in the lateral
photograph.
104. Facial and intraoral
photographs of patient T.H.C.
after 10.5 months of
protraction treatment. After
protraction with miniplate,
Class III malocclusion
has been corrected.
105. Pretreatment records
of a 10-year, 8-month-
old female patient
(J.E.C.) with skeletal
Class III malocclusion
and anterior crossbite.
Loss of space for
upper right second
premolar attributable
to mesial movement
of right first molar.
Showing concave
profile in lateral
photograph.
106. Facial and intraoral photographs of J.E.C. during the maxillary
protraction with miniplates. Pendulum appliance was used
simultaneously to gain space for the right second premolar.
107. Results
No significant differences were found between the 2
groups in dentofacial morphology except for the lower
incisal inclination (IMPA was 80.68° for the miniplate
group and 85.69° for the RME group, P 0.05).
Skeletal Changes
The anterior and posterior cranial base lengths were
found to increase significantly in both treatment groups.
However, no significant differences were found between
the 2 groups.
108. The measurement SNA was found to increase
significantly by 3.29° in the miniplate group and 2.22° in
the RME group. The changes were significantly greater
in the miniplate group.
Similarly, the measurement A to perpendicular to FH was
found to increase by 3.42 mm in the miniplate group and
2.13 mm in the RME group . The changes were also
significantly greater in the miniplate group .
109. With treatment, the mandible was found to rotate
downward and backward in both treatment groups.
The mandibular plane angle (FMA) was found to
increase significantly in both the miniplate group
(1.01°) and the RME group (1.74°).
A greater increase in the forward position of the maxilla
was found in the miniplate group compared with the RME
group. Such a difference can be explained by direct
transmission of the orthopedic force to the maxillary
sutures in the miniplate group.
110. The placement of miniplates in the zygomatic buttress
area is closer to the center of resistance of the maxilla
which is usually located half way between the infraorbital
rim and the mesial buccal cusp of the maxillary molars.
In contrast, orthopedic force in the RME group is directed
along the occlusal plane rather than at the center of
resistance of the maxilla. Consequently, bone remodeling
occurs not only at the circummaxillary sutures but also
within the periodontal tissues.
Palatal expansion has been shown to disarticulate the
maxilla and initiate cellular response in the suture,
allowing a more positive reaction to protraction forces.
111. The maxillary first molars were found to move backward
0.46 mm compared with a forward movement of 3.26 mm
in the RME group.
Vertically, significant extrusion of the maxillary first
molars were found in both treatment groups.
The maxillary incisors were found to move forward by
0.11 mm in the miniplate group compared with 1.83 mm
in the RME group.
Dentoalveolar changes
113. Heymann et al (2010)said that the Protraction face-mask
therapy or reverse-pull headgear (RPHG) is perhaps the
most common approach for early treatment of young Class
III patients with maxillary deficiency
This approach is limited in that the forces are applied to
the teeth, resulting in uncertain skeletal and often
unwanted dentoalveolar effects.
114. For satisfactory clinical improvement, excellent
compliance with an extraoral appliance is required and
treatment regimns recommended wearing the appliance
for 12 to 16 hours per day for 9 to 12 months.
most investigations have described some limited
orthopedic effect on the maxilla (2–3 mm of advancement
on average), clockwise rotation of the mandible, and
dentoalveolar changes consistent with treatment of Class
III malocclusion (proclination of maxillary incisors and
retroclination of mandibular incisors).
115. Long-term follow-ups of maxillary protraction indicate
a 25% to 33% chance of relapse to negative overjet after
all mandibular growth is complete.
Since dentoalveolar changes tend to be the most prone
to relapse, it seems advantageous to minimize the
dentoalveolar effects while maximizing the orthopedic
correction.
Heymann et al used. An alternative treatment of early
Class III with intermaxillary elastics from a temporary
anchorage device that might permit equivalent
favorable skeletal changes without the unwanted
dentoalveolar effects.
116. MATERIAL AND METHODS
Criteria for participation in the study were 9–14 years of
age at the start of treatment, skeletal Class III due
primarily to maxillary deficiency (determined by clinical
examination including profile evaluation), Class III dental
occlusion determined by the permanent first molars or
overjet ≤0 mm, and sufficient dental development, to
avoid injury to unerupted mandibular permanent canines
during surgical placement of the miniplates.
117. Six consecutive patients (3 boys, 3 girls; ages, 10–13
years 3 months) with Class III occlusion and
maxillary deficiency were treated by using
intermaxillary elastics to titanium miniplates
All 6 patients were at prepubertal cervical vertebral
maturation stages.
In the surgical procedure, 4 miniplates were placed in
each patient—1 in each infrazygomatic buttress of the
maxilla and 1 in the anterior mandible between and
inferior to the left and right permanent lateral incisor
and canine.
118. The modified titanium
miniplates incorporated an
intraoral attachment with a
locking fixation screw to allow
customizable traction hooks
In all sites, the miniplates were placed with the
attachment arm exiting through attached tissue at or near
the mucogingival junction.
119. The miniplates were loaded 3 weeks after surgery. One
elastic was placed on each side to give vectors of force
downward and forward for the maxilla and backward and
upward (counterclockwise) for the mandible. The patients
were instructed to wear elastics 24 hours per day.
The elastics were chosen to provide an
initial force of approximately 150 g to
each side, increased to 200 g after 1
month of traction and to 250 g after 2
months. The forces were measured
with the patient in maximum
intercuspation by using a Correx force
gauge
120. The miniplates were loaded 3 weeks after surgery. One
elastic was placed on each side to give vectors of force
downward and forward for the maxilla and backward and
upward (counterclockwise) for the mandible. The patients
were instructed to wear elastics 24 hours per day.
The elastics were chosen to provide an
initial force of approximately 150 g to
each side, increased to 200 g after 1
month of traction and to 250 g after 2
months. The forces were measured
with the patient in maximum
intercuspation by using a Correx force
gauge
121. All patients in this study showed a negative change on
the anterior surfaces of the condyles and a positive
change on the posterior surfaces, suggesting that there
was at least some posterior repositioning of the
mandible.
All 6 patients had a positive change at the surface region
that encompassed the upper lip as the underlying hard
tissues of the maxilla changed.
In 5 of 6 patients, the entire nasal complex appeared to
rotate anteriorly and superiorly, suggesting that the forces
from the TADs were dispersed widely through the
nasomaxillary complex.
122. It has been well documented that facemask treatment
results in an increase in maxillary incisor angulation and a
decrease in mandibular incisor angulation.
Dentoalveolar effects observed in this study tended to be
in the opposite directions, possibly as a result of
alteration of soft-tissue equilibrium forces.
The use of CBCT for this study allowed the treatment
changes to be visualized and described in greater
detail than with 2-dimensional (2D) imaging alone.
124. Bong-Kuen Cha and Peter W. Nga(2010)
Investigators have shown that maxillary protraction
with palatal expansion therapy is an effective method
for treatment of Class III patients.
Although intervention in the primary or early mixed
dentition may provide a better orthopedic response,
treatment started in the late mixed or early permanent
dentition can elicit reasonable orthopedic response when
the circummaxillary sutures are still patent.
125. One of the limitations in maxillary protraction with a
conventional tooth-borne type appliance is the loss of dental
anchorage, especially in the dynamic period of the mixed or
late permanent dentition.
Many investigators have attempted to design an absolute
anchorage system for maxillary protraction. A priori
ankylosed teeth, intentionally ankylosed maxillary
deciduous canines, or osseointegrated titanium implants
can be used as an absolute anchorage for protraction
treatment.
126. However, the use of ankylosed teeth limits the orthopedic
treatment to only the early mixed dentition period.
Skeletal anchorage by the use of miniscrews or
miniplates are gaining popularity as a source of absolute
anchorage in contemporary orthodontics.
Kuen Cha.B and Nagan.P quantified and compared the
effects of maxillary protraction using surgical miniplates
as anchorage to maxillary protraction in conjunction with
an expansion appliance (rapid maxillary expansion
[RME]).
127. Methods
Two treatment modalities for the correction of Class III
malocclusions in growing patients were compared by
treating 2 groups of patients. One group of 25 patients (16
girls and 9 boys) was treated with a facemask combined
with a bonded RME and a second group of 25 patients
(15 girls and 10 boys) treated with a facemask employing
a surgical miniplate as anchorage.
128. Schematic illustration shows a curvilineartype miniplate
fixed with 3 self-tapping miniscrews on the zygomatic
buttress area. The end of the miniplate was exposed between
the canine and first premolar area, located over the
keratinized attached gingiva to prevent gingival irritation.
Protraction force is approximately 300-400 gm per side and
the line of force is 30° to the occlusal plane.
129. The placement of miniplates was carried out under local
anesthesia.
The anchor plates were placed at the zygomatic buttress
area to avoid damage to the underlying developing tooth
buds of the permanent teeth
Protraction force is most often applied after 3 or 4
weeks of healing.
The facemask was inserted after maxillary expansion or
placement of the miniplate the total force applied was
400 g/side.
130. Patients in both treatment groups were instructed to
wear the appliance for at least 14-16 hours a day.
Posttreatment cephalometric radiographs were taken
when a normal dental relationship was obtained with
an overjet of 2-3 mm.
The average treatment time in miniplate group was 9.2 2.4
months and the RME group 8.5 2.4 months.
131. Pretreatment records of 11-
year, 4-month-old male
patient (THC) with Skeletal
Class III malocclusion and
anterior crossbite, crowding.
The concave profile is
shown in the lateral
photograph.
133. Facial and intraoral
photographs of patient T.H.C.
after 10.5 months of
protraction treatment. After
protraction with miniplate,
Class III malocclusion
has been corrected.
134. Pretreatment records
of a 10-year, 8-month-
old female patient
(J.E.C.) with skeletal
Class III malocclusion
and anterior crossbite.
Loss of space for
upper right second
premolar attributable
to mesial movement
of right first molar.
Showing concave
profile in lateral
photograph.
135. Facial and intraoral photographs of J.E.C. during the maxillary
protraction with miniplates. Pendulum appliance was used
simultaneously to gain space for the right second premolar.
136. Results
No significant differences were found between the 2
groups in dentofacial morphology except for the lower
incisal inclination (IMPA was 80.68° for the miniplate
group and 85.69° for the RME group, P 0.05).
Skeletal Changes
The anterior and posterior cranial base lengths were
found to increase significantly in both treatment groups.
However, no significant differences were found between
the 2 groups.
137. The measurement SNA was found to increase
significantly by 3.29° in the miniplate group and 2.22° in
the RME group. The changes were significantly greater
in the miniplate group.
Similarly, the measurement A to perpendicular to FH was
found to increase by 3.42 mm in the miniplate group and
2.13 mm in the RME group . The changes were also
significantly greater in the miniplate group .
138. With treatment, the mandible was found to rotate
downward and backward in both treatment groups.
The mandibular plane angle (FMA) was found to
increase significantly in both the miniplate group
(1.01°) and the RME group (1.74°).
A greater increase in the forward position of the maxilla
was found in the miniplate group compared with the RME
group. Such a difference can be explained by direct
transmission of the orthopedic force to the maxillary
sutures in the miniplate group.
139. The placement of miniplates in the zygomatic buttress
area is closer to the center of resistance of the maxilla
which is usually located half way between the infraorbital
rim and the mesial buccal cusp of the maxillary molars.
In contrast, orthopedic force in the RME group is directed
along the occlusal plane rather than at the center of
resistance of the maxilla. Consequently, bone remodeling
occurs not only at the circummaxillary sutures but also
within the periodontal tissues.
Palatal expansion has been shown to disarticulate the
maxilla and initiate cellular response in the suture,
allowing a more positive reaction to protraction forces.
140. The maxillary first molars were found to move backward
0.46 mm compared with a forward movement of 3.26 mm
in the RME group.
Vertically, significant extrusion of the maxillary first
molars were found in both treatment groups.
The maxillary incisors were found to move forward by
0.11 mm in the miniplate group compared with 1.83 mm
in the RME group.
Dentoalveolar changes
141.
142. Keinprasit et al (2010) treated a case of severe
maxillary hypoplasia in a 21 years old male Thai
patient with a complete unilateral cleft of primary
and secondary palates by internal distraction
osteogenesis for maxillary advancement.
143. Case history:
The patient was a 21 years old Thai male with a
repaired right complete unilateral cleft lip and palate
with severe Class III malocclusion and very severe
midfacial hypoplasia.
The cleft lip was repaired at the early infant period, and
the cleft palate at four years of age. Secondary alveolar
bone grafting was completed when he was 19. There
was velopharyngeal insufficiency that produced
hypernasal speech.
144. Extraoral examination showed a symmetrical
dolicofacial type with a concave profile and flat
paranasal areas due to underdeveloped maxilla. The
mandibular plane was steep.
145. Intraorally, there was a pegged-shape lateral incisor
in the lateral segment next to the cleft area.
The occlusion was Class III with total crossbite and 6
mms negative overjet.
There was an incomplete anterior bite with 0% vertical
overlapping.
The lower dental midline was deviated 1 mm to the left.
146. Both maxillary first premolars and left maxillary first
molars were missing with residual spaces.
There was 3 mms crowding in the anterior region.
Mandibular first molars were missing with the second
molars drifted into the spaces.
147. Cephalometric analysis showed a
skeletal Class III relationship
(ANB-6.5°) due to retrognathic
maxilla (SNA 82.5°, A-Nperp -6
mms) and prognathic mandible
(SNB 89°, Pog-Nperp +3 mms).
Open vertical skeletal relationship
(PP-MP 29.5°) was presented due to
anterior inclination of palatal plane
(SN-PP 1.5°) and opening rotation
of mandibular plane (SN-MP 31°),
causing decreased facial index
(73%).
148. Treatment:
The treatment plan was orthodontic treatment combined
with maxillary distraction osteogenesis to correct skeletal
discrepancy and improve facial appearance.
Predistraction orthodontic treatment to level and align
the dentition and close all edentulous spaces was
planned.
The objective of maxillary distraction is to advance and
anteriorinferiorly reposition of the maxilla, so that
mandibular set back would not be necessary to reduce
its prognathism.
149. After the distraction, treatment would be completed by
finishing orthodontics.
The treatment was begun in early 2004 for arch leveling,
aligning, space closures and inter-arch coordination.
Predistraction orthodontic preparation was completed in
2007
150.
151. The surgical approach for distraction was similar to a Le
Fort I osteotomy.
Circumvestibular incision and complete osteotomy
were performed and the maxilla was then down-
fractured.
The distraction vector was oblique to the occlusal plane
to move the maxilla anteriorly and inferiorly. The devices
were activated to test their function and the mobility of
the released bone segment and then returned to the
starting positions.
The surgical wound was closed with the two activation
ports exited through the mucosa into the buccal
vestibules.
153. Both Synthes® screws were activated by oral surgeons
at a rate of 0.25 mm twice a day for 2 weeks and then
0.5 mm once a day for another week until 8 mms
maxillary advancement with 1 mm positive overjet were
obtained.
After 4 months of complete bone consolidation, the
distractors were removed and postdistraction orthodontic
treatment was started. Intermaxillary Class III elastics
were applied to produce 3 mms incisor overjet for
overcorrection and prevention of anterior crossbite
relapse. Satisfactory occlusion was achieved. There was
no longer any posterior crossbite.
157. Baek et al (2010) reported a case report of a patient was a
12 year 1 month old girl with CP only. She presented with
concave facial profile, anterior crossbite (29 mm overjet), and
anterior open bite (22 mm overbite). Cephalometric analysis
showed skeletal Class III malocclusion with maxillary
hypoplasia.
158. (ANB, -5.4; A to N perp, -3.4 mm), steep mandibular plane
angle (FMA, 32.7u), and a skeletal age after the pubertal
growth spurt according to the cervical vertebrae maturation
index (CVMI, stage 4). Her condition was one of the
contraindications for conventional facemask therapy.
159. FM/MP therapy was started 4 weeks after placement
of the miniplates according to the protocol.
During protraction, the fixed appliances were placed
to align the dentition.
160. After 16 months of FM/MP therapy, there was significant
forward movement of the point A (A to N perp, 5.6 mm). The
ANB angle was changed from - 5.4° to 2.9°, and a Class II
canine and molar relationship, normal overbite, and overjet
were obtained. A slight counterclockwise rotation of the
occlusal plane angle (-1.8) was interpreted to mean that there
was almost no side effect such as extrusion of the upper
molars.
161. Although the FMA was increased 4.3, the anterior open
bite was corrected by downward and forward movement
of the maxilla. Slight labial tipping of the upper incisors
(U1 to SN, 2.0°) occurred after correction of anterior
crossbite and open bite
163. Kircelli et al (2006) presented a case report of
a 11-year-old girl was referred with a complaint of‘‘small
and separated teeth’’ and ‘‘lower jaw projection.’’ Medical
history of the patient was noncontributory other than her
parents were cousins. Furthermore, her elder brother
presented with similar complaints of maxillary hypoplasia
and hypodontia. Clinical and radiological examination
revealed severe hypodontia and microdontia. Twenty-one
of her permanent teeth were missing, whereas number 11,
21, 36, 46 existed in the dental arch and germs of the
number 15, 37, and 47 could be detected on the panoramic
radiograph.
164.
165. Furthermore, microdontia existed both in her
primary and permanent dentition. The maxillary
arch was deficient sagittally and transversally, so
that there was an eight mm negative overjet and
a bilateral buccal crossbite relationship with the
lower jaw.
166. A depression of the midfacial structures included the
maxillary and infraorbital regions with a relative
prominence of the mandible, inadequate projection of
the nasal tip and an old face appearance with an
unesthetic smile constituted general features of the
patient . She also had nasal respiratory problems
causing mouth opening during sleep.
167.
168. Three treatment options were considered for maxillary
advancement. The first option was to delay treatment
until growth has ceased and to correct the jaw
relationship by orthognathic surgery. The second option
was to apply rigid external distraction together with
complete Le Fort I osteotomy. The third option was to
try to take advantage of the sutural growth potential by
applying extraoral force with a face mask via rigid
skeletal anchors placed to the maxillary bone.
Treatment options
169. A titanium miniplate designed by Erverdi16 (MPI,
Tasarımmed, Istanbul, Turkey) was used as a rigid
skeletal anchor to attach the elastic orthopedic forces to
the maxilla. Multipurpose miniplates were to be placed
on both sides of the apertura piriformis and on the lateral
nasal wall of maxilla. Rapid maxillary expansion was also
planned to correct the transversal maxillary deficiency
and to disturb the circummaxillary sutures.
170. Because the maxillary dentition was insufficient, it was
decided to place intraosseous titanium screws (two 3 eight
mm IMF screws, Leibinger, Germany) on the palatal
bone, near the alveolar crests, to provide anchorage for the
expansion appliance. After routine surgical preparations,
patient received general anesthesia. Bilateral mucosal
incisions were made on labial sulcus between lateral incisor
and first cuspid region.
171. Then, mucosal flaps were carried inferiorly, the muscles
and periosteum were incised and reflected
superomedially, exposing the apertura piriformis and the
lateral nasal wall of maxilla on both sides. Once an
adequate space was achieved for miniplate placement, the
nasal mucoperiosteum was elevated. Multipurpose
miniplates were meticulously contoured to the bilateral
lateral nasal wall, and straight extensions were bent to
hook shape providing retention for face mask elastics and
projected into the oral cavity through three mm
mucoperiosteal incisions made inferiorly on the attached
gingiva.).
172. Subsequently, for final stabilization of the bone plates
three, 2.0 mm screws (five mm length) were placed with a
1.3 mm diameter drill under copious irrigation
Simultaneously, four intraosseous bone screws were
placed in the anterior and posterior palatal region, close to
the alveolar crests, bilaterally .After soft tissue healing,
orthopedic forces were applied.
IMF screws placed in anterior and
posterior palatal region.
173. Impressions and stone casts were obtained with th IMF
screws in place. The screws were blocked out with wax on the
stone model, and an acrylic plate was prepared with an
expansion screw in the midline. Appliance adaptation was
checked intraorally and then connected to the IMF screw
heads using cold curing methyl methacrylate–free acrylic
resin (Ufi Gel hard, Voco GmbH, Cuxhaven, Germany). One of
the parents was asked to activate the screw a quarter turn
once a day.
Construction of the intraosseous screw– supported
expansion appliance
Intraosseous screw–supported
maxillary expansion appliance.
174. An elastic force of approximately 150 g was applied
bilaterally to the miniplate extensions after the adaptation
of face mask (Leone spa, Firenze, Italy). After being sure of
the stability, the force was increased gradually to 350 g.
The direction of the force was adjusted approximately 308
to the occlusal plane, and the patient was asked to wear
the face mask full time except during meals.
175. The application of the orthopedic forces via elastics directly
to the anterior part of the maxillary bone by using miniplate
anchorage resulted in a remarkable improvement in the
middle face. Together with the maxillary bone advancement,
significant enhancement in the soft tissue profile revealed
improved facial esthetics. The maxilla was expanded from the
median palatal suture, and seven mm of expansion was
achieved across the buccal segments. Coordination of the
dental arches both in the sagittal and transversal planes
created improved physiological functions.
178. Early Class III Treatment with a Hybrid
Hyrax-Mentoplate Combination
JCO/JANUARY 2011
179.
180. Clinical Procedure
After administration of topical anesthesia, two mini-implants
with interchangeable abutments (2mm × 9mm, Benefit
system) are inserted with a contra-angle screwdriver next to
the midpalatal suture, near the second and third palatal rugae.
181. Benefit system. A. Mini-implant. B. Laboratory
analog. C. Impression cap. D. Wire abutment with
wire in place. E. Bracket abutment. F. Standard
abutment. G. Slot abutment. H. Screwdriver for
abutment fixation
182. An implant diameter of 2mm is recommended for
better stability.A dental probe is used to measure soft-
tissue thicknesses from anterior to posterior and to
identify a region with thin mucosa, which will ensure
primary stability and avoid long lever arms. Pre-
drilling is not needed in young patients because of the
low mineralization of the bone.
183. At the same appointment, bands are fitted to the upper first
molars. After transfer caps are placed over the miniscrews, a
silicone impression is taken.*** If the space between the
mini-implants is narrow, the transfer caps can be cut to fit
side-by-side. The angular relationship of the transfer caps is
maintained by connecting them with a light-cured adhesive
in the mouth. After the impression is taken, the laboratory
analogs are placed over the transfer caps.
184. Two standard Benefit system abutments are then screwed over
the laboratory analogs. A standard Hyrax‡ palatal split screw
is connected by laser-welding it anteriorly to the two
abutments and posteriorly to the molar bands. The appliance
can still be fitted over the implants even if they are not
absolutely parallel.
185. The Hybrid Hyrax is inserted one week later by pressing it
gently over the mini-implants and alternately screwing the two
abutments onto the mini-implants. To facilitate the installation,
we recommend use of a light-cured cement for the molar
bands. The expansion screw should be activated immediately
after insertion of the Hybrid Hyrax; turning the screw 180°
twice a day results in a daily expansion of .8mm.
186. The oral surgeon places the titanium Mentoplate in the
mandible under local anesthesia. After preparation of a
mucoperiosteal flap, the two extensions are shortened and
adapted. The extensions should penetrate the soft tissue in the
attached mucosa
187. After the Mentoplate is fixed with four screws, the flap is
flipped back and sutured.
They have treated seven young Class III patients (three males,
four females; average age 10.6) with this Hybrid Hyrax-
Mentoplate combination. All patients began wearing Class III
elastics§ (3.5oz, 3/16 ") immediately after maxillary expansion.
The following are representative cases.
188. Case 1
A 9-year-old female presented with a severe skeletal (Wits:
−8.3mm) and moderate dentoalveolar Class III malocclusion.
A Hybrid Hyrax and Mentoplate were placed.
189.
190.
191. After one week of rapid maxillary expansion, Class III elastics
were applied. The soft tissues appeared healthy throughout
treatment.
192. After nine months of treatment, the patient’s occlusion and
profile showed impressive improvement (Wits: −2.8mm).
193.
194. A 12-year-old male presented with a severe skeletal Class III
malocclusion (Wits: −5.9mm) and negative overjet
195. A Hybrid Hyrax was activated one week after insertion of the
Mentoplate and Benefit mini-implants. Resin bite-opening
blocks were bonded to the lower molars to facilitate correction
of the anterior crossbite. No soft-tissue impingement by the
Mentoplate was observed.
196.
197.
198. After six months, the patient demonstrated substantial occlusal
and skeletal improvement (Wits: −2.7mm). The profile was
also markedly improved 14 months later, at the end of
orthodontic treatment.
199. Case 2. Reverse overbite corrected after six months of
treatment. B. Profile after 20 months of orthodontic
treatment.
200. Discussion
Among the seven young patients, none of the 14 Benefit
mini-implants placed in the anterior palate has failed, and no
complications have been observed. We prefer the anterior
palate for insertion of the Hybrid Hyrax because of its
superior bone quality and relatively low rates of miniscrew
failure.7 The attached mucosa offers better stability than other
areas, and there is no risk of tooth damage. Usually the
screws are removed without anesthesia.
The Hybrid Hyrax can also be used for rapid palatal expansion
in patients with inadequate anterior dental anchorage
(missing deciduous teeth or premolars with underdeveloped
roots). The heavy forces associated with other methods may
cause root damage or curvature if the premolars have just
erupted.
201. None of the seven Mentoplates has failed in our patients,
although we observed mild irritation in cases where the plate
extensions passed over the mobile mucosa. Based on these
results, it appears that the Mentoplate could be useful not only
in orthopedic treatment, but in orthodontic correction as well.
Considering that mini-implant failure rates in the alveolar
process are relatively high, the mental region appears to be a
better site for mandibular skeletal anchorage it is the “anterior
palate” of the lower jaw.
202. The Hybrid Hyrax-Mentoplate approach for early Class III
treatment offers several advantages over other methods:
• Forces are applied directly (by the Mentoplate) or transferred
indirectly (Hybrid Hyrax) to skeletal structures.
• The appliances are nearly invisible; no extraoral devices are
required.
• Rapid expansion opens the midpalatal sutures for better
maxillary protraction.
• Anchorage is stable and reliable.
• Insertion is possible before complete eruption of the lower
canines.
203. • The placement procedure is less invasive than when multiple
miniplates are used.
• The upper and lower arches remain fully accessible for
orthodontic tooth movements.
This combination of the Hybrid Hyrax and the Mentoplate
seems to offer a promising approach for early treatment of
patients with Class III malocclusion.
204.
205. Nonsurgical correction of a Class III
malocclusion in an adult by miniscrew-
assisted mandibular dentition distalization
American Journal of Orthodontics and Dentofacial Orthopedics
June 2013 Vol 143 Issue 6
206. In this case report, they introduce a nonsurgical
treatment of an adult with a Class III malocclusion with
miniscrew-assisted mandibular teeth distalization.
At the beginning of the therapy, the multiloop edgewise
archwire technique resulted in an unsatisfying
smile because of the excessive proclination of the
maxillary incisors. Then they used a miniscrews in the
mandible as anchorage for the distal en-masse
movement of the mandibular dentition and obtained an
excellent treatment outcome ultimately.
207. DIAGNOSIS AND ETIOLOGY
The patient was a 20-year-old Mongolian woman
who had a Class III facial type and slight crowding with
a complete Class III relationship. Her chief complaint
was an anterior crossbite. Her medical history showed
no contraindication for orthodontic therapy, and no
one in her direct family had skeletal Class III features.
208.
209.
210. The photographs taken before treatment showed
symmetric facial structures. The patient had a concave
facial profile, a protrusive lower lip, and an acute
nasolabial angle.
211. Her maxillary anterior teeth were retrognathic, with
inadequate display when smiling.
The mandibular dental midline was deviated 2.0 mm to
the right, although the maxillary dental midline was
coincident with the facial midline. There were no signs
or symptoms of temporomandibular joint dysfunction.
212. A cephalogram and a panoramic radiograph were taken
before treatment. The cephalometric analysis and its
tracing showed that the SNB angle 81.7 and ANB angle,
2.6. The panoramic radiograph showed no other
abnormal signs, except that the 2 germs of the
mandibular third molars were tipped mesially.
213.
214. TREATMENT OBJECTIVES
The treatment objectives were to (1) obtain a
harmonious facial profile by decreasing the protrusion
of the mandible; (2) improve the occlusion, including
correction of the anterior crossbite, establishment of
ideal overjet and overbite, and achievement of Class I
molar relationships; and (3) place the dental midlines
in the middle of the patient's face.
215. TREATMENT ALTERNATIVES
The first alternative was combined surgical and
orthodontic treatment. The anterior crossbite would be
corrected with a mandibular setback, and the concave
profile would be improved as well. However, they
decided that her skeletal problem was not sufficiently
excessive to require orthognathic surgery.
The second alternative was orthodontic treatment
with extraction of 4 premolars. Through the retraction
of the mandibular anterior teeth and the mesial
movement of the maxillary molars, the anterior crossbite
and Class III molar relationships would be corrected,
and the concave facial profile would be camouflaged.
216. Nevertheless, her mandibular incisors were not suitable
for much distal movement because of the thin trabecular
bone in the mandibular anterior area that could damage
the periodontal tissues by gingival recession,
fenestration or dehiscence.
The third alternative was to extract the mandibular
third molars and use the multiloop edgewise archwire
technique to obtain distal en-masse movement of the
mandibular arch with short Class III elastics. Thereby,
the anterior crossbite would be corrected, the molar
relationships would be changed into Class I, and her
concave facial profile would be camouflaged as well.
217. After they discussed the 3 alternatives with the patient,
she chose the third option and promised to cooperate in
extracting the third molars and wearing the Class III
elastics.
218. TREATMENT PROGRESS
Orthodontic treatment began on November, 2007.
The mandibular third molars were extracted before
bonding. Preadjusted 0.022-in brackets were bonded to
all teeth. Alignment and leveling with sequential nickel-
titanium archwires were achieved in 12 months, ending
with 0.018 X 0.025-in stainless steel wires. After that,
0.018 X 0.025-in stainless steel multiloop edgewise
archwires with progressive tip-back bends were placed
in both arches.
219.
220. The patient was instructed to wear the short Class III
elastics (3/16 in, 6 oz; 3M Unitek, Monrovia, Calif) for
24 hours per day.
221. The anterior crossbite was corrected substantially
4 months later. However, the maxillary incisors were
proclined remarkably. Class I molar relationships were
not completely established, although the overall
occlusion was improved significantly. Thus, in the 17th
month, they took a set of photos and a cephalogram,
and made a cephalometric analysis to re-estimate her
treatment.
222. The superimposition of the cephalograms showed that
the correction of the anterior crossbite was mostly
because of the proclined maxillary incisors without
obvious distal movement of the mandibular incisors.
Also, the excessively proclined maxillary anterior teeth
made her facial profile worse,
especially when smiling.
223. To reinforce the distal en-masse movement of the
mandibular dentition, they modified the treatment plan.
They replaced the orthodontic appliance with 0.022-in
Damon III self-ligating brackets and used miniscrews
instead of the multiloop edgewise archwire technique.
When rebonding, the maxillary incisor brackets were
rotated 180, assisting in labial root torque at the
rectangular wire stage.
224. The miniscrews were implanted vertically in the external
oblique ridge areas of the bilateral mandibular ramus
between the mandibular first and second molars, where
the greatest thickness of buccolingual bone was found.
225. After 3 months of re-leveling, they started to draw the
mandibular dentition distally using nickel-titanium
coil springs with 300-g forces on each side. The spring
was connected from the miniscrew to the hook
between the mandibular canine and the first premolar.
At the same time, 0.019 X 0.025 beta-titanium alloy
wire was used to control the root position of the
maxillary incisors.
226. Six months later, the anterior overbite and overjet were
improved remarkably, and the labial inclination of
maxillary teeth was also much better.
227. The total treatment duration was 32 months. The multiloop
edgewise archwire technique was used for 4 months, and it
took 12 months for the distal en-masse movement of the
mandibular dentition with miniscrews. The miniscrews were
stable all the time and removed under topical anesthesia.
228.
229. TREATMENT RESULTS
A harmonious facial balance, a charming smile, and
a well-aligned dentition were obtained. The anterior
crossbite was corrected, and Class I molar relationships
were achieved. The post-treatment cephalometric
analysis and the superimposition show that the ANB
angle increased from - 2.6to -1.5, and the SNB angle
decreased from 81.7to 79.1.
According to the superimposition, the mandibular
anterior teeth were retracted about 4 mm without
negative lingual inclinations.
230. The movement of the mandibular first molar could be
considered almost bodily translation because its crown
was moved 4.0 mm distally, and its roots were moved
3.0 mm distally. The maxillary incisors were moved
labially under control with good inclination (U1-SN,
77.7). The SN-GoGn angle increased from 36.1to 38.9,
and S-Go/N-Me decreased from 61.3% to 59.4%,
indicating that the mandible had rotated clockwise
slightly. The patient was satisfied with the treatment
results, and the outcome was stable after 1 year of
retention.
231.
232. Because the direction of the retraction force applied to the
miniscrews is above the center of mandibular arch resistance, the
mandibular arch can be rotated counterclockwise when distalized,
leading to a flattened occlual plane. On the other hand, molar
distalization is beneficial for decreasing a negative overbite. With
the combination of these 2 factors, the anterior crossbite can be
corrected, and ideal overbite and overjet can be established. The
dotted line represents the retraction force; the red point represents
the center of mandibular arch resistance.
233. Distalization of the mandibular dentition with
mini-implants to correct a Class III malocclusion
with a midline deviation
(Am J Orthod Dentofacial Orthop 2010;137:135-46)
234. When distalizing the mandibular dentition with a
mandibular C-implant, the most important consideration
is its position. The placement site should be as close as
possible to the mesial surface of the mandibular first
molar because this will help achieve optimal distalization
of the mandibular dentition. The initial tooth movement in
distalization is posterior movement of the second molar
by using a sliding jig that is connected to the main
archwire, followed by moving
the other teeth posteriorly.
235.
236. While the second molar is distalizing, the first molar also
moves distally as a result of drifting. When molar
distalization is complete, the premolars will also begin to
move with the sliding jig. While the premolars are
distalizing, spaces might develop between the anterior
teeth. To retract the anterior teeth with en-masse
retraction, closing loops are placed between the lateral
incisors and canines, and connected to the C-implants
by elastics.
237. Because intermaxillary elastics are not applied to the
maxillary dentition, mesial movement of the maxillary arch
and extrusion of the maxillary molars are avoided, and the
incisors are not flared. This case report describes the
distalization of the mandibular dentition to treat a dental
Class III malocclusion with a deviated midline by using
C-implants.
238. DIAGNOSIS
The patient was a woman, aged 23 years 5 months, whose chief
concern was protruding mandibular teeth. Her medical history was
noncontributory, and occasional clicking of her temporomandibular
joints (TMJ) was noted in her dental history.
The pretreatment facial photographs show an acceptable facial
profile, despite mild midface deficiency and slight mandibular
prognathism.
239. The clinical Examination showed a Class III molar and
canine relationship that was more significant on the
right side. Other findings included an anterior edgeto-
edge relationship, a midline discrepancy, mild
mandibular anterior crowding, and mesial angulation of
the mandibular posterior teeth. The lower midline was
not coincident with the facial midline and was shifted
to the left by 2.5 mm.
240. The maxillary third molars and the mandibular right third
molar were missing. There was only slight contact
between the maxillary right second molar and the
opposing tooth because of the Class III molar
relationship.
241. The cephalometric analysis showed a skeletal Class III
relationship with a high mandibular plane angle and a
slightly retrognathic maxilla. The anterior facial height
was slightly long relative to the posterior facial height.
The incisor position and interincisal relationship were
within normal limits except for the retroclined maxillary
incisor. The patient was diagnosed with a skeletal Class
I malocclusion with mild maxillary deficiency and a
dental Class III relationship.
242. TREATMENT OBJECTIVES
A mandibular premolar extraction plan would be
a relatively simple and stable way to resolve the anterior
crossbite. Complex treatment mechanics and many
tooth movements would not be needed. However, the
patient did not want extractions (except for the third
molars) or changes to her facial appearance; she
wanted only to correct the incisor relationship. Although
the maxillary incisors were slightly upright, the patient
requested that they not be allowed to move forward.
Therefore, we rejected the premolar-extraction treatment
option.
243. Based on the initial records and the patient’s desires,
the treatment objectives were to distalize all mandibular
teeth, improve the interincisal relationship to have
normal overjet and overbite, shift the mandibular midline
to coincide with the facial and maxillary midlines, and
achieve Class I canine and molar intercuspal
relationships. A conventional fixed appliance was
prescribed.
244. TREATMENT ALTERNATIVES
Maxillary advancement surgery was not a viable treatment
option because the skeletal deficiency was not significant, and
the patient was pleased with her facial appearance.
Maximum anchorage and interarch elastics were discussed for
en-masse movement of the mandibular dentition. She
refused the interarch elastics because of their visibility. Her
occasional clicking was also a matter of concern because it
might lead to TMJ dysfunction symptoms during orthodontic
treatment. Therefore, mandibular distalization with a C-
implant in the posterior dentition and intra-arch elastics was
the treatment of choice. After distal movement of the
mandibular dentition, a full fixed appliance would be used in
the maxillary dentition for finishing.
245. TREATMENT PROGRESS
Two C-implants, 1.8 mm in diameter and 8.5 mm long,
were placed in the interdental spaces between the
mandibular second premolars and first molars. Bone
quality in the mandible was good, and the implants were
loaded immediately. A 0.016-in NiTi initial archwire was
used for leveling and distalization of the mandibular
posterior dentition. Intra-arch elastics (1/4-in, 3.5 oz)
were applied from the 0.7-mm-diameter stainless steel
sliding jig to the neck of the C-implant for distalization of
the mandibular second molar and anterior decrowding.
246.
247.
248. The maxillary dentition was not bonded initially because
the dental and facial midlines were coincident,
and no forward movement of the anterior teeth was
desired.
While the mandibular dentition was distalizing,
drifting occurred. Therefore, a power chain was applied
to correct the midline
249.
250. This applied an intrusive movement to the mandibular
incisors because the NiTi archwire was not stiff, and
elastics were applied from the incisors to the apically
placed C-implant. To correct the anterior open-bite
tendency from the force direction of the elastics, the
mandibular archwire was changed to a 0.016 3 0.022-in
NiTi archwire and then a 0.016 3 0.022-in stainless steel
archwire with closing loops.
251.
252. As the mandibular molars moved distally, the maxillary
molars were extruded. To correct the extrusion, the
maxillary dentition was bonded for intrusion and leveling
of the maxillary molars. A Class I molar relationship of
the mandibular left dentition was achieved by using a
sliding jig.
254. The mandibular right dentition was distalized 6 mm but
still required further movement.
The sliding jig was continuously applied to the
mandibular first molar. The mandibular premolars
continued to move separately
255.
256. The closing loop of the 0.016 3 0.022-in stainless steel
archwire was used as a hook for mandibular en-masse
retraction.
Distalization of the mandibular dentition and midline
correction took 18 months. The fixed appliances were
removed, and retention was provided by maxillary and
mandibular fixed retainers.
257.
258.
259. TREATMENT RESULTS
The active treatment period was 18 months. The
patient’s facial profile was mostly unchanged.
A Class I canine and molar relationship and normal
tooth alignment with better midline coincidence,
and normal overjet and overbite were achieved
260. The maxillary incisors moved forwardbslightly. The
mandibular incisors were retracted considerably and
extruded. The upper and lower lips moved very little. The
interincisal angle increased as the mandibular incisors
uprighted and the ANB angle remained unchanged. The
posterior facial height anterior facial height ratio and the
FMA were only slightly changed in spite of the significant
mandibular molar distalization as seen in the
superimposition.
The patient was pleased with the treatment results.
An ideal incisor relationship and Class I canine and
molar relationship were obtained.
263. Skeletal Class III malocclusion
correction using miniscrew implants
Journal of the World Federation of
Orthodontists 2 (2013) e151ee158
264. Diagnosis and etiology
A Hispanic woman aged 21 years, 10 months with a chief
complaint of an anterior crossbite presented for orthodontic
Treatment. Facial analysis showed no gross asymmetries. A
mesoprosopic and ovoid facewas observed. A straight to
concave facial profilewas recorded in the lateral view.
265.
266. Lateral cephalometric radiographic, panoramic
radiographic, and cast models were used for the skeletal
and dental diagnosis. Hypodivergent skeletal Class III
pattern was observed, with an anterior mandibular
functional shift of 0.5 mm. Analysis of the cervical
vertebral maturation showed no growth remaining.
267. There was an anterior crossbite of her upper incisors,
with a negative over jet of 0.5 mm in centric relationship
(e1 mm in centric occlusion). Molars were in bilateral
Class III occlusion. Posterior lingual crossbite of the
upper left bicuspid and both upper second molars was
observed.
268. Upper and lower incisors were excessively proclined,
with mild maxillary spacing and mild mandibular
crowding. The lower third molars were present, but no
upper third molars were visible in the radiographs. Her
upper centrals and laterals were abnormally shaped,
with some incisal wear on the centrals.
269. Treatment objectives
The treatment objectives were to: 1) improve facial
profile by establishing normal over jet; 2) achieve Class I
molar and canine relationship; 3) resolve the crowding in
the mandibular arch; 4) close space in the maxillary
arch; and 5) improve the transverse relationship
between the upper and lower dental arches.
270. Treatment progress
Treatment was started with placement of a banded lingual arch
on the mandibular second molars to maintain lower intermolar
width during crossbite correction. Self-ligating brackets with .022-
in slots and MBT prescription were bonded on all teeth but the
lower second molars. A sequence of three pairs of archwires was
used in the upper and lower dentition. A .014-in nickel-titanium
(Ni-Ti) archwire was used for initial alignment, followed by
0.019 0.025-in Ni-Ti archwires and 0.019 0.025-in stainless
steel archwires.
271. After placement of the lower stainless steel archwire, the
third molars were extracted. Then two 6-mm MSIs were
placed buccally between the mandibular second premolars
and the mandibular first molars. The MSIs were placed close
to the first molar mesial root, to allow for as much
distalization as possible. Indirect anchorage was initially used
to distalize the lower first and second molars into the
extraction site of the third molar.
272.
273. This was done by tying a stainless steel ligature from the MSIs
to the lower premolars and placing open Ni-Ti coil springs
mesial and distal to the first molars. Although no distal force
was applied to the lower incisors from the MSIs at this time,
mild over jet was achieved with the use of Class III elastics for
2 months, elimination of 0.5-mm anterior shift, and changing
the upper arch form from square to ovoid.
274. After obtaining a half-step Class II molar relationship, power
arms were placed between the lower canines and the lower first
premolars. Direct anchorage was used by placing a closed Ni-Ti
coil spring from the MSIs to the power arms to distalize the lower
incisors, thus preventing additional flaring of the upper incisors.
The power arms allowed better bodily movement due to the
line of action being closer to the center of resistance of the
anterior teeth.
275.
276. Detailing and finishing (bends and individual torque)
were performed to achieve better intercuspation after
Class I molar and canine relationships were observed.
After 2 years and 4 months of treatment, the fixed
appliances and MSIs were removed and retention was
provided by a maxillary wraparound retainer and
mandibular fixed retainer bonded to the canines.
277. Results
The patient’s chief complaint was addressed with correction of the
anterior crossbite, and she was pleased with the overall treatment
results. The lateral photograph and cephalometric radiograph showed
improvement of the profile due to slight upper lip advancement. There
were no significant skeletal changes with treatment.
278. Skeletal Class III pattern showed slight improvements.
The maxilla showed no anteroposterior changes. The mandible
showed slight reduction of the protrusion at B point (decrease in
sella, nasion, point B angle). The reduction of dentoalveolar
mandibular protrusion improves the maxillomandibular
relationship due to a greater point A, nasion, point B angle and
smaller Wits appraisal. The vertical dimension showed minimal
changes.
279. Ideal incisor relationship was obtained, and a proper cuspid and
molar Class I relationship was achieved. The upper and lower
teeth showed changes in an anteroposterior position.
The upper incisors were advanced and proclined more than
anticipated. Class III elastics, 17torque brackets on the upper
centrals, and a change to a more ovoid arch form likely
contributed to the upper incisor flaring.
280. The lower incisors were retracted, with some retroclination
and slight extrusion. Mandibular incisors were initially
retracted more than 3 mm, resulting in excess over jet. Class
II elastics were needed (2 months) to correct the resultant
over jet.
Upper molars were mesialized approximately 1.5 mm, and
maxillary space was closed. There was no significant change
in the vertical dimension of the upper teeth. The lower
molars were distalized approximately 3 mm (4 months of Ni-
Ti coil spring use), with slight distal inclination, helping to
correct the mild crowding as well the anteroposterior
relationship.
281. Wraparound retainers for the maxillary teeth and fixed
retainers to the lower anterior teeth were delivered. The
patient was referred to her general dentist for continued care
and reshaping of the upper incisors. Final records showed
acceptable results.
282.
283. C-Orthodontic Microimplant for Distalization of Mandibular
Dentition in Class III Correction
Angle Orthodontist, Vol 75, No 1, 2005
284. A 16-year-old-male presented with the chief complaint
of missing lower anterior teeth, lower anterior protrusion,
and eagerness for an attractive smile. He had a history of
missing lower central incisors because of a traffic accident
at 7 years of age. No space maintainer was used during
growth. The extraoral examination revealed the facial
characteristics of a mild Class III lower anterior protrusion
patient with a deep labiomental sulcus and a prominent and
everted lower lip with an increased interlabial gap.
285.
286. The intraoral examination revealed a severe asymmetrical
dental Class III malocclusion with an anterior shallow overbite
and a negative overjet. There was no occlusal centric
relationship discrepancy on closure. Skeletal and dental
characteristics showed a slightly prognathic mandible,
protruded upper incisors, and procumbent lower incisors.
287. The temporomandibular joint function was normal. The
maxillary midline was coincident with the facial midline.
However, the mandibular midline did not coincide with the
facial midline due to the lost space in the missing lower
anterior dentition.
288. The radiographic examination revealed that the patient
had a concave profile with an ANB angle of 21.58, a slightly
prognathic mandible (SNB angle 838, SN-Pg angle 848,
and Wits appraisal 29 mm), a high mandibular plane (FMA
298), and protrusive upper incisors (interincisal angle 1168,
maxillary incisor to NA angle 338, maxillary incisor to NA
distance 10 mm) (Figure 4). The pretreatment panoramic
radiograph illustrated excellent periodontal support and the
presence of impacted third molars.
289.
290. Treatment plan
The patient requested only conventional orthodontic
treatment and did not want his upper front teeth to be
protruded any further. Based on the results of the
cephalometric and study model analyses, the treatment
objectives were to establish a Class I molar and canine
relationship, create an ideal overjet and overbite, improve the
occlusal interdigitation, regain space to allow an esthetic
dental restoration of the lower anterior edentulous area, and
improve the facial balance.
291. However, en masse retraction of the full lower dentition by
conventional orthodontic treatment could cause the reactive
extrusion of the upper anchor teeth and upper anterior
protrusion with a change in the upper midline. Therefore, the
treatment strategy was to place a Cimplant in the upper molar
area and to apply Class III mechanics between lower dentition
and upper C-implant using Class III elastics to correct the
Class III molar and canine
relationship.
292. Treatment progress
Two C-implants were implanted in the interdental spaces
between the upper second premolars and first molars. After
incision of the mucosal area, drilling was carried out at
1500 rpm of drill speed and 15 Ncm of drill pressure with
profuse irrigation with isotonic saline solution. The 1.5-mm
diameter guide drill was selected when drilling to depth in
cortical bone. The screw part was placed clockwise into the
prepared site using internal and external sterile saline cooling.
293.
294. After an 8-week healing period, the head part of C-implant
was assembled into the screw part by lightly tapping with
a small mallet 1 to 2 times. Immediate loading is possible,
mainly in areas where dense bone is located and where
primary stability can be achieved.
295.
296. Treatment was initiated with the leveling and distalization
of the lower posterior dentition. Because of the patient’s
dental and skeletal problems, no bonds were placed on the
maxillary anterior and right posterior teeth. However, brackets
were placed on the upper left posterior teeth, followed by the
placement of a segmented 0.022 3 0.028 inch preadjusted arch
wire appliance for intrusion of the upper left second molar.
298. The lower third molars were all removed. The patient was
instructed to wear Class III elastics as long as possible to
move the lower dentition distally.
The missing lower anterior space was almost completely
regained after 12 months of active tooth movement. The fixed
appliances were removed, and a tooth positioner was used for
1 month for finishing. The retention was provided by an upper
fixed retainer and removable lower Hawley retainer.
299. Treatment results and discussion
After treatment, a Class I molar and canine relationship
with midlines coincident, correct tooth position, and proper
alignment were present. Ideal overjet, overbite, and facial
balance were also achieved, and the incisors were not
procumbent.
300.
301. The lower dentition was notably distalized 5 mm on the left
and 2 mm on the right side. Cephalometric analysis showed a
slight downward and backward mandibular movement as well
as an asymmetric distalization of the lower dentition.
302. The FMA changed slightly from 29 to 30 degree. The backup
with the C-implant hook can be assumed not to change the
position of the upper molars, which minimized any increased
steepness of the mandibular plane. However, the intrusive
force on the upper left second molar using a sectional archwire
is believed to have caused a slight extrusion of the upper
molars.
303. We should have used the C-implant as an anchorage appliance
for intrusion of the upper left second molar simultaneously
with lower distal movement. The occlusal plane was not
changed significantly after treatment because of extrusion of
both the upper and lower posterior teeth during distal
movement (SN to OP angle 118 to 138). The upper incisors
were slightly protruded (FH-U1 angle 1258–1278, maxillary
incisor to NA distance 10–11 mm, maxillary incisor to NA
angle 338–378). The lower incisors were uprighted and
retracted. In this case, lower lateral incisors were used as the
landmarks for deciding the lower incisor position because of
the missing lower central incisors (IMPA 918–838, FMIA
608–678, mandibular incisor to NB distance 7 mm to 5 mm,
mandibular incisor to NB angle 308–238).
304. The lips were competent in repose (upper lip to E-plane 0 mm
to 0.5 mm, lower lip to E-plane 3 mm to 0.5 mm). The
interincisal angle was improved to a normal range (1168–
1218). The ANB changed a little during treatment (SNA 828–
82.58, SNB 838–838, Wits appraisal 29 mm to 25 mm). The
posterior/anterior facial height ratio was slightly increased
after treatment (91/142 mm, 64.2% to 93/144 mm, 64.6%).
The entire lower dentition was distalized successfully by
using the C-implant as a hook for elastics. The treatment
result was quite acceptable, and the patient was pleased
with the final treatment results despite the space for the
anterior restoration being slightly deficient.
