ORTHODONTIC CORRECTION OF OCCLUSAL PLANE CANTING IS PRESENTED

1. Faculty of Dentistry
Mansoura Egypt
Dr Maher Fouda
Professor of orthodontics
Orthodontic correction of
occlusal-plane canting
Part 2

3. Cant of the Occlusal Plane
Slight deviations in incisal plane
symmetry have been shown to be less
esthetic.4
This plane should be parallel to the upper
lip and eyes The cant of the
occlusal plane usually can be corrected
by the use of continuous symmetric
archwires (not segmented), the
application of symmetric forces (such as
a cervical
facebow), and the efforts of the patient to
squeeze the teeth together to distribute
symmetric occlusal forces.

4. (a) Pretreatment frontal view of an unesthetic
smile resulting from a
canted occlusal plane, midline deviation,
supernumerary maxillary left canine,
and high lip line. (b) Pretreatment frontal intraoral
view. (c) Posttreatment
frontal view of the now esthetic smile. The
excessive gingival display is a result of
the short upper lip. (d) Posttreatment frontal
intraoral view.

6. A 22-year-old Korean man’s chief complaints were
facial asymmetry and mandibular prognathism . He had
traditional facial asymmetry, with a
skeletal Class III pattern, including anterior crossbite,
midface deficiency, and significant mandibular prognathism.
This patient had mild midfacial deficiency and
proclined maxillary anterior teeth.

7. His mandible was shifted to the right according
to the cant of the maxillary occlusal plane due to the
unilateral extrusion of the maxillary left premolars and
molars. The mandibular occlusal plane also was
canted slightly by unilateral extrusion of the left
mandibular molars

8. This extrusion accentuated
his asymmetry. The mandibular right incisors
and first premolar showed some extrusion attendant
to an anterior crossbite. The patient also had a
posterior crossbite caused by an absolute transverse
discrepancy. The maxillary midline was 1 mm to the
right of the midsagittal plane, and the mandibular
midline was off by 3 mm in the same direction.

9. The
anterior teeth of both arches had typical Class III
dental compensations. No tooth size-arch length
discrepancy was present in either arch. Both left and
right first molars showed a Class III dental relationship.
The patient appeared to have a relatively large
tongue; there was no family history of Class III
mandibular prognathism and facial asymmetry.

10. The original treatment plan included maxillary and
mandibular surgical intervention after presurgical orthodontic
treatment to extract the maxillary first premolars.
Maxillary surgery was refused because of the cost
and postoperative considerations. A compromise nonextraction
treatment plan was accepted with bilateral
sagittal split ramus osteotomy (BSSRO) and reduction
genioplasty. Surgical treatment was planned after the
maxillary occlusal plane cant had been corrected.

11. TREATMENT OBJECTIVES
The treatment objectives for this patient were to (1)
intrude the extruded teeth, (2) correct the canted maxillary
occlusal plane, (3) correct the midline shift, (4)
correct the posterior crossbite by expanding the narrow
maxillary arch, (5) correct facial asymmetry and mandibular
prognathism, and (6) improve facial appearance.

13. TREATMENT ALTERNATIVES
Generally, LeFort I osteotomy combined with mandibular
BSSRO is used for patients with canted occlusal
planes and facial asymmetry. Two maxillary first or
second premolars can be extracted to upright proclined
maxillary incisors and allow sufficient mandibular setback
before preorthodontic treatment..

14. Alternatively,
unilateral maxillary impaction of the extruded molar
area by segmental osteotomy can be used instead of
LeFort I osteotomy, but there are no common treatment
options for facial asymmetry that do not include surgery

15. TREATMENT PLAN
After review of treatment options, the patient accepted
the following treatment plan.
1. Extract all 4 third molars.
2. Bond both arches from second molar to second
molar.
3. Expand the maxillary dentition.
4. Decompensate with long Class III elastics.

16. 5. To correct extruded teeth, implant miniscrews in
the maxillary left molar area, the mandibular left
molar area, and the right mandibular canine area.
6. Perform surgery, including BSSRO, with asymmetric
setback and reduction genioplasty.
7. Finish the occlusion after surgery.

17. TREATMENT PROGRESS
After extraction of the third molars, treatment
began by bonding both arches with 0.022 0.028-in
standard edgewise brackets. Initial leveling was accomplished
in 3 months with 0.016-in and 0.018-in round
nickel-titanium wires followed by 0.018 x 0.025-in
stainless steel archwires. A transpalatal arch was used
to assist in expanding the maxillary intermolar width.

18. Stainless steel wires (0.020 0.025 in) were
used with quarter-inch, 5-oz Class II elastics to decompensate
the maxillary and mandibular incisors .

19. Initially, four 8-mm miniscrews, with a
diameter of 1.2 mm, were
implanted in the left side of the maxilla and the
mandible between the second premolars and the first
molars, and between the first and second molars . The
miniscrews were implanted at chairside
under local anesthesia.

20. All miniscrews were implanted
with a pilot hole drilled with a 1-mm round bur
without incision of gingival tissue. Placement of the 4
miniscrews took approximately 15 minutes. Three
months after the first surgery, 2 more 8-mm miniscrews
were implanted between the maxillary left first and
second premolars (Fig 6, bottom row) and the mandibular
right canine and first premolar.

21. The miniscrew
between the mandibular right canine and first premolar
fractured during implantation, and a second miniscrew
of the same size was implanted just above the first site.

22. Elastics were used to intrude the teeth and
changed every 2 to 3 weeks. The intrusion of the left
molars took approximately 6 months; however, the
intrusion of the mandibular right canine required only 3
months. The intrusion achieved during treatment provided
sufficient space for the asymmetric mandibular
setback. The mandibular BSSRO and genioplasty were
performed .

23. Postoperative orthodontic treatment
took 5 months to finalize the patient’s occlusion.
The miniscrews were removed by the orthodontist
before the orthodontic treatment was completed. The
fractured miniscrew in the mandibular left canine
region was not removed then because of the difficulty
of removal. Ultimately, the failed implant was removed
by an oral surgeon after orthodontic finishing.

24. Retention
included fixed canine-to-canine lingual retainers in
both arches. Additionally, a maxillary circumferential
Hawley retainer was delivered for nighttime wear.
Gum-chewing also was recommended to assist in
preventing relapse of the intruded molars.

25. A, Postreatment cephalogram; B, superimposed tracings.

26. Posteroanterior cephalogram comparison: A, initial; B, before surgery, significant correction
of canted maxillary occlusal plane; C, final.

27. Maxillary advancement
with retroclination of maxillary anterior teeth
would have improved the midfacial profile and allowed
sufficient mandibular setback. The accepted alternative
of camouflage treatment without maxillary surgery
resulted in insufficient mandibular setback, so genioplasty
was added.

28. The patient showed clinically significant
improvement of facial asymmetry, even though he
had had only single-jaw surgery. We believe that a
better result would have been achieved with a 2-jaw
approach after the extraction of both maxillary first
premolars. Unfortunately, as for this patient, many
presumably ideal treatment plans must be modified.

29. Changing a canted occlusal plane requires either intrusion
of extruded molars or extrusion of intruded molars.
Extrusion of teeth can cause clockwise rotation
of the mandible, producing a longer face.
Correction of canted maxillary occlusal plane
with miniscrews.

30. Extrusion of teeth can cause clockwise rotation
of the mandible, producing a longer face. Intrusion
of molars is more stable and reduces facial height.
Because this patient would benefit from a reduction
in facial height, intrusion of molars was preferred.
Previous studies showed excellent intrusion of molars
by using skeletal anchorage with miniplates. For
our patient, miniscrews were chosen for skeletal anchorage.
The placement and removal of miniscrews
require less surgery and are easier than placement of
miniplates.

31. Because of the difficulty of placing miniscrews
between adjacent tooth roots, some doctors prefer
miniplates to miniscrews. Miniplates are used in the
zygomatic buttress area and midpalatal suture area
rather than the interdental area However, periapical
x-ray films taken by a parallel technique can be
useful to evaluate the space between roots
(a) Panoramic and (b) intra-oral pre-treatment
radiographs of the dentition as used to visualise the
interproximal area between the left maxillary second
premolar and first molar teeth. (c) The intra-oral radiograph is
repeated to confirm the position of a mini-implant in this site.

32. In dental
arches, the curve of Spee and mild root curvature of the
mandibular molars create larger interdental spaces between
the mandibular molars when compared with the
maxillary molars.

33. Few complications occur when
miniscrews are used in the mandibular molar area.
Because of molar root configuration, the spaces between
cervical areas of the teeth and the middle of roots
are wide. Kyung et al recommended 30° to 40°
angulations in the maxillary teeth and 10° to 20°
angulations in the mandibular molars. The angulation
of miniscrews in the mandibular molar region is not of
great importance, because there are wide interdental
spaces and considerable cortical and cancellous bone in
the buccal shelf area.

34. As a result, 80° to 90° horizontal
angulations to the long axes of the maxillary molars are
recommended when maxillary buccal bone is not sufficient.
In the maxilla, there are relatively narrow
spaces followed by large convex root curvature and
distally tipped molar angulation. Large-diameter miniscrews
(over 1.8 mm) showed better stability than
smaller (1.2 mm) ones..

35. However, the authors recommend small, 1.2-mm diameter
miniscrews for the narrow maxillary molar area.
One concern related to smaller implants is that, although
there is sufficient room between roots, surgical
failure is possible. Further studies on this surgical
technique are needed to lessen the surgical risk.
a) A pre-treatment panoramic, and (b) preinsertion
and (c) post-insertion intra-oral radiographs. The
insertion site between the left maxillary second premolar and
first molar roots is highlighted in red in images (a) and (b).
Root divergence has been performed to widen the
interproximal space before radiograph (b) was taken.

36. Diagrams of the premolar and first molar teeth
where (a) the second premolar bracket has been bonded
with mesial tip to cause (b) mesial tipping of this root during
the fixed appliance alignment phase and hence an increase
in this interproximal space.

37. NJDSR. Volume 3, Number 1, 2015

38. Many patients have canted occlusal planes caused
by unilaterally extruded maxillary molars or
asymmetric mandibular vertical development.
Until recently, there was no reliable nonsurgical
method to correct this condition.

39. Various methods of molar intrusion have been
introduced, including posterior bite blocks,
highpull headgear, posterior bite blocks with high-
pull headgear, and active vertical correctors with
magnets. Unfortunately, there are limitations to
these methods in adult patients, and the
appliances are highly
dependent on patient cooperation.

40. Recently, miniscrews and miniplates have been
introduced to aid orthodontic mechanics, and
they have been reported to provide skeletal
anchorage to permit molar intrusion.

41. DIAGNOSIS:
A 16-year-old female reported with chief
complaint of forwardly placed upper front teeth
Extra oral examination reveals convex profile, high clinical
Frankfurt mandibular angle, incompetent lips, increased
nasolabial angle..

42. Intraoral examination reveals class I molar
relation on right side and class II on left side.
Class I canine relation on right side and class II
on left side. Mild crowding is present with upper
and lower anteriors

43. There is highly placed canine on left side.
The lower midline was shifted towards left
side by 2mm. The maxillary occlusal plane is
canted on right side due to extrusion of
anteriors, premolars and molars on same side.

44. Cephalometrically patient presents with
skeletal class II pattern, vertical growth
pattern, proclined upper and lower anteriors
and protruded upper and lower lips.

45. TREATMENT OBJECTIVES:
The treatment objectives for this patient were to:
1. Correct the upper and lower crowding.
2. Correct the increased overjet.
3. Correct the molar and canine relation on left side.
4. Correct the canted maxillary occlusal plane.
5. Correct the lower midline shift.

46. TREATMENT PLAN:
The treatment plan included extraction of
upper I premolars, lower I premolar on right
side and II premolar on left side. Cant
correction using miniscrews by intruding
upper right quadrant.

47. TREATMENT PROGRESS:
After extraction of upper I premolars, lower I premolar on
right side and II premolar on left side, treatment began by
bonding both arches with MBT 0.022 X 0.028 prescription.
Initial leveling and aligning was accomplished in 4 months with
0.014 -in and 0.018-in round nickel titanium wires followed by
0.017 X 0.025-in rectangular nickel titanium wires and then
followed by 0.019 X 0.025 stainless steel working wire.
Intraoral right side showing implants with elastics for intrusion

48. Anchorage control was done by
transpalatal arch. Initially, two 8 mm
miniscrews with a diameter of 1.2mm
were implanted on the upper right
quadrant between upper right lateral
incisor and canine and upper right
second premolar and first molar
Intraoral right side showing implants with elastics for intrusion

49. The miniscrews were implanted at chair side under local anaesthesia. Elastics
were used to intrude the teeth and changed every 2 to 3 weeks.
The intrusion of the upper right quadrant took approximately 6 months. After
the
required amount of intrusion achieved the elastics were removed and
ligature wire was tied from miniscrews to arch wire to maintain the
intrusion achieved.
corrected maxillary cant

50. A 3.5-mm posterior open bite was achieved on the right
side by intrusion. The remaining space was closed by
active tiebacks and overjet was corrected. The
miniscrews were removed before the finishing stage
Extraoral front showing pre(A) and post(B) correction

51. Changing a canted occlusal plane requires either
intrusion of extruded molars or extrusion of intruded
molars. Extrusion of teeth can cause clockwise
rotation of the mandible, producing a longer
face. Intrusion of molars is more stable and
reduces facial height. Because this patient
would benefit from a reduction in facial
height intrusion of molars was preferred.

52. Prior to the placement of miniscrews periapical
x ray films are taken to evaluate the space
between the roots. In the maxilla there are
relatively narrow spaces followed by large
convex root curvature and distally tipped molar
angulation .Kyung et al recommended 30 to 40
degree angulations in the maxillary teeth.

53. Traditional oral implants require a waiting
period of at least 4 months before occlusal
loading. Miniscrews, however are different
because they have been used for
temporary anchorage and force applied are
much lower. Complete osseous integration
therefore is not necessary.

54. Orthodontic forces of 250 grams or less have
been successfully applied to miniscrews after
soft tissue healing. One theory that supports
early loading is that mechanical retention
between the screw and the bone is sufficient
to withstand normal orthodontic force levels.

55. Intrusive mechanics: Conventional mechanics
essentially consist of characterstics of extrusive
mechanics. Conversely the TAD is generally located
apically compared with the brackets and in this
location the mechanics are advantageous in achieving
intrusion.

56. When considering the effects of molar intrusion to decide
whether a molar should be intruded the intermaxillary
occlusal relationship should be considered along with
condition of bone and attached
gingival should be evaluated. Stability of molar
intrusion can be achieved by overcorrection.

57. To avoid root resorption, intrusive force levels should
be kept near optimal. Burstone suggested applying
20 grams of intrusion force for an incisor. Melsen
and Fiorelli used about 50 grams buccolingually in
an adult. About 200 grams force was used to intrude
molars in this study.

58. There are no long-term studies about the stability of
intrusion with miniscrews in the orthodontic literature.
It has been suggested, however, that normal occlusal
forces might help prevent relapse of the intruded teeth.
Proffit stated the equilibrium theory: occlusal forces
can assist in maintaining the correction.

59. Intrusive forces applied apically to the buccal tooth surface
result in rotational movement, leading to molar flaring.
Therefore, intrusive forces should be applied to both the
buccal and lingual surfaces. This allowed the use of a
transpalatal arch to control the buccal flaring of the
maxillary molars instead of adding intrusive forces on the
lingual surface along with buccal root torque This
mechanical system worked well and eliminated the need for
a miniscrew in the midpalatal suture area.

61. An 11.2-year-old female patient consulted for a facial
asymmetry that had progressed during the last year.
The physical exam revealed deviation of the chin
toward the left side. An occlusal plane cant was
observed as a result of increased vertical growth of
the right side .
A, Patient with gross asymmetry noticed during growth. C, Lower incisor inclination trying to compensate for the
facial asymmetry showing no midline deviation in relation to the maxilla
at the incisal edge.

62. B, Posteroanterior cephalogram showing the significant maxillary and mandibular
asymmetry.

63. Deviation of the
lower dental midline was not notable since the
lower incisors had compensated with their axial
inclination for the present mandibular asymmetry.

64. A comparative scintigraphy of the
mandibular condyles revealed the presence of 60.3%
of the contrast media on the right condyle and
39.7% on the left condyle; this confirmed the
diagnosis of active hyperplasia of the right condyle.
D, Bone scan reflecting abnormal uptake of the radioactive
marker on the right condyle.

65. Based on this diagnosis, a high intracapsular
condylectomy of the right condyle was performed
and an infrazygomatic mini-plate was placed on
the right side. In addition, mini-screws were placed
in the palate to serve as skeletal anchorage in
conjunction with the mini-plate in order to level the
occlusal plane without tipping by intruding the teeth
on the right side.
A, Force from right buccal mini-plate to intrude the buccal segment and
correct the occlusal cant. B, Intentional lateral open bite
created by the intrusion of the right maxillary buccal segment.

66. The posterior
open bite obtained in the right side after the
intrusion and the deviation of the lower midline
toward the right side after the condylectomy.
A, Force from right buccal mini-plate to intrude the buccal segment and correct
the occlusal cant. B, Intentional lateral open bite
created by the intrusion of the right maxillary buccal segment.

67. Orthodontic treatment with extraction of the
first lower premolars was then performed. The
patient had extractions of the maxillary first
premolars during a prior orthodontic treatment. The
infrazygomatic mini-plate was used as anchorage to
extrude the mandibular right buccal segment, close
the posterior open bite, and level the lower occlusal plane.
A and B, Force delivered by an intermaxillary elastic to erupt the lower right buccal
segment to match the intruded maxillary right
buccal segment. C, No intrusive or extrusive mechanics were attempted on the left side.

68. Even though the facial
asymmetry improved after the condylectomy and
the leveling of the occlusal plane, a deviation of the
chin toward the left side and a difference in volume
in the area of the mandibular corpus and ramus was
still noticed. Larger facial tissue volume on the right
side was evident when compared to the left side.
A, Facial asymmetry was
improved, although a
significant deficiency in tissue
mass was observed on the left
side compared to the right.
B, Maxillary cant was
corrected but the
asymmetrical animation of the
lower lip and general left to
right asymmetry was more
obvious on smile.

69. A medical computed tomography (CT) was ordered to
quantify the degree of asymmetry and define the
amount of volume that was missing .
Medical computed tomography was used to evaluate the (A) soft tissue and (B) hard tissue
asymmetry. Using a mirroring technique,
a custom-made implant was designed to fill the missing hard and soft tissue volume on the left
lower face.

70. A mirror image of both sides was virtually analyzed
and a polymethylmethacrylate (PMMA) implant was
designed , inserted, and fixed with two
2-mm x 13-mm titanium screws
(lomas, PSM Medical Solutions, Tuttlingen,
Germany) on the left side to restitute the missing
tissue volume.
(B) hard tissue
asymmetry. Using a
mirroring technique,
a custom-made
implant was
designed to fill the
missing hard and
soft tissue volume on
the left lower face.
A, Insertion of
the custom-
made implant
secured with
two screws
laterally to the
left ramus.

71. There was an improvement in overall
symmetry. The facial contour definition was refined
and made symmetrical with secondary effects on
the smile. An important aspect to highlight is that
the left animation of the lower lip commissure,
which was significantly asymmetrical, was improved
with the tissue volume augmentation via the facial
implant and the lateral displacement of the chin
achieved with the genioplasty.
Improvement in overall asymmetry evaluated (A) at rest and (B) on smile. Note the more symmetrical soft tissue
volume and animation

72. Dental Press J Orthod. 2014 Mar-Apr;19(2):126-41

73. Occlusal plane inclination is a daunting challenge
faced by orthodontic treatment. It is mainly caused by
dental issues such as loss and/or ankylosis of antagonist
teeth, deleterious oral habits, inappropriate orthodontic
bonding leading to asymmetric dental alignment,
skeletal disharmony or a combination of factors.
Intraoral frontal view depicting asymmetric open bite
due to long persistent unilateral digit sucking habit.
infraoccluded and ankylosed
maxillary upper left canine.

74. However, to compensate such changes, the maxillary
occlusal plane is also impaired so as to establish a
balance between the mandibular changes.

75. Treatment of those pathologies depends on the
cause and degree of severity of the change. In cases of
significant facial alterations, dental correction may be
achieved by mini-implants or miniplates; however, no
improvements in facial esthetics will be observed. Thus,
an approach combining orthognathic surgery and
orthodontic
treatment is recommended. Nevertheless, in
borderline cases in which patient’s chief complaint is
not facial, orthodontic approach alone is employed with
considerable forseability.

76. Mini-implants became popular and allowed those issues
to be addressed in a more predictable manner, yielding
excellent results.30 Nevertheless, other biomechanical
procedures that do not require skeletal anchorage can be
employed to treat occlusal plane inclination. The rational
use of biomechanics by means of SAT and asymmetric
cantilevers proves to be a feasible option.

77. As shown
in Figure 24A, the patient, whose chief complaint was
having an asymmetric smile, presents occlusal plane
inclination.
Due to the absence of facial complaints, she was
advised to undergo dental treatment, only, which would
be performed with asymmetric cantilevers.

78. Clinical illustration showing the use of two asymmetric cantilevers. A, B, C) Initial case; D, E,
F) Intrusion on the right side and extrusion on the left
side for correction of the occlusion plane; G, H, I) After mechanics was applied.

79. Initially, alignment and leveling were carried out in
association with anchorage preparation of the reactive
member by means of a palatal bar.
The 0.019 x 0.025-in wire was achieved and the arch
was segmented into three pieces (from #16 to #14, from
#13 to #21 and from #22 to #25). Initial alignment and
leveling did not include tooth #27 which was coupled
with #16 by a palatal bar.

80. The segment going from #13 to #21 underwent a
clockwise movement, with the point of force application
between #13 and #12, where greater intrusion was observed.
A 70-gf force was applied by a cantilever made of
0.017 x 0.025-in β-Ti wire (Fig 24B).

81. The segment going from #22 to #25 underwent an
anti-clockwise movement, with the point of force application
between #22 and #23. Extrusive force was applied by
a cantilever made of 0.017 x 0.025-in steel wire. In order
to achieve flexibility and decrease the LF ratio, a helix was
placed in the wire with a force of (Figs 24D, 24E, 24F).

82. The side effects produced by the mechanics were balanced
by the palatal bar reinforced with the use of a steel
stabilization 0.019 x 0.025-in archwire placed from #16
to 14 on the right side. Treatment lasted for three months,
followed by rebonding of brackets and new procedures of
alignment and leveling (Figs 24G, 24H, 24I).

83. Orthodontics – Basic Aspects and Clinical Considerations

84. The next patient is a 31-year-old female who was once
referred to a maxillofacial surgeon
with a chief complaint of gummy smile. The surgeon had
performed a maxillary impaction
and an advancement genioplasty on the patient without
presurgical orthodontic treatment.
The patient eventually was not satisfied with the results
and was therefore, referred to the
orthodontist. Her chief complaints were gummy smile and
the present spacing.

85. The pretreatment facial photographs exhibit facial
asymmetry along with a cant of maxillary
occlusal plane. Clinical examination revealed a
deviated midline (2mm). Spacing could be
noticed at different areas both in maxillary and
mandibular dentition. The four first
premolars had already been extracted in earlier
years to help alleviate crowding, but no
further orthodontic treatment was carried out on
the patient to consolidate the arches.

86. Cephalometric analysis revealed a retrusive
mandible (ANB angle 7°) and an increased
IMPA angle (94°). The SNA angle was within the
normal limits (82‫;)؛‬ however, SNB angle
was decreased (75‫..)؛‬

87. In other words, patient had a skeletal class II
profile accompanied with
mandibular dental compensation . The patient
was not willing to
undergo another orthognathic surgery to correct
the existing problems and since the four
first premolars had already been extracted,
extracting yet another tooth was out of question

88. pretreatment facial and intraoral photographs, the four first
premolars had already been extracted; notice the canted maxillary
occlusal plane and
excessive gingival display.

89. pretreatment cephalogram, cephalometric tracing and panoramic
radiographs.

90. The treatment goals were to address the patient’s chief
complaints, i.e correct the canted
occlusal palne and close the spaces. Two mini-implants of
1.4 in diameter and 6.0 mm in
length were placed between the roots of maxillary lateral
incisors and canines. Initially a
continuous 0.016 NiTi arch wire was placed as the initial
arch wire. With the progress in the
size of the arch wire, after 2 months, a 0.016×0.022-in
stainless steel segmented arch wire
was placed extending from left to right maxillary lateral
incisors.

91. In order to decrease the
gummy smile, the patient was asked to wear 3
16 - in latex elastics from the anterior segment
to the mini-implants. Since, the equal use of both mini-
implants would not correct the
canted occlusal plane, the patient was asked to wear the
latex elastic to the left mini-implant
two days in a row and to the right mini-implant once
every three days .

92. Consecutive use of latex elastics in the anterior
region has the disadvantage of irritating the
labial frenum, thus, decreasing the patient
cooperation. After 1 month, in lieu of latex
elastics, elastomeric chains were used.

93. After intrusion of the upper anterior teeth and
correction of its cant, continuous 0.016 SS arch wire
was inserted in the upper and lower
arches. Midline correction and space closure was
carried out in both arches at this stage.
Meanwhile, the upper anterior teeth were tied to the
miniscrews to prevent their relapse
after intrusion.

94. progress facial and intraoral
photographs, mini-implants are
placed
between the roots of lateral incisor
and canine to address gummy smile
and canted occlusal
plane.

95. After 13 months, the treatment was completed. The
patient was very well satisfied with the
changes in her appearance. The gummy smile and
canted occlusal plane had resolved
significantly. Fixed retainers extending from second
premolar to second premolar were
bonded in the maxilla and mandible . Post treatment
cephalometric
tracing revealed 6 mm intrusion of maxillary incisors
without a significant difference in the
inclination of upper incisors (upper incisors to SN
angle, pretreatment : 106‫,؛‬ post treatment:105)

96. post treatment facial and intraoral photographs, notice the
correction of the canted occlusal plane and gummy smile.

97. post treatment cephalogram,
superimposition of pretreatment (red)
and post treatment (black)
cephalometric tracings and panoramic
radiograph.

99. If a patient has an anterior open bite and the diagnosis is
favourable for treating the condition dentally ,extrusion can
often be accomplished conventionally .
Conventional extrusion arch
mechanics to close an open bite
and/or correct a cant of the
anterior occlusal plane
A , The force system delivered
by an extrusion arch.
B ,Frontal view showing a
patient with a cant of the
anterior occlusal plane and
an extrusion arch tied only
on the patient’s left to
deliver asymmetric force to
correct the cant .
C, frontal view of the patient
after the cant has been
corrected .

100. Unless precausions are taken ,a lateral open bite
may occur over time as the molar tips forward ,if a
continuous wire or posterior segment is in place .

101. In this patient the left anterior teeth are extruded to
close the open bite and level the occlusal plane by
applying the extrusive force off –center.
In such situation ,TADs can be used to stabilize
against undesired tooth movement .

102. Vertical Occlusal Evaluation
The presence of a canted occlusal plane could be the result
of a unilateral increase in the vertical length of the
condyle and ramus. Similarly, the maxilla or temporal
bone supporting the glenoid fossa could be at different
levels on each side of the head. Such asymmetries are
often detected by clinically evaluating the patient. The
cant in the occlusal plane can be readily observed by
asking the patient to bite on a tongue blade to determine
how it relates to the interpupillary plane
Patient biting on a tongue
blade to assess the severity
of the cant of the maxillary
and mandibular occlusal
planes in relation to
the interpupillary line.

104. If intrusion does not
progress symmetrically and
bilaterally ,skewing of the
arch form or canting of the
occlusal plane from the
frontal view may occur
(a)Increased application of
intrusive force on one side
(double arrow )leads
easily to asymmetric
intrusion

105. Canting of the occlusal plane can expand to the frontal
plane as one side is more intruded than the other .
(a)Frontal intraoral view.(b)Frontal facial view .

106. Control of the inclination of the occlusal plane in intrusive
mechanics .
For posterior intrusion to be successful from the second order
view point ,the inclination of the occlusal plane is to use two
forces from two implants that are set apart ,the production of
moments is related to the amount of applied forces and the
distances(dashed red line ) between the forces
(B)To control the second molar ,intrusive force should be
applied posteriorly ,near the second molar area.
If the placement of implants between molars is not feasible
,©a bonded extension arm.

107. Control of the inclination of the occlusal plane in intrusive
mechanics .
If the placement of implants between molars is not feasible
,a© bonded extension arm or (d)a second –order bend can be
used .
(e)Two forces are essential to produce moments ,even with a
single implant .
A step bend or (F) an L –LOOP can also be used to increase
biomechanical efficiency .

108. Even though most of the researches and data that are available
points to the fact that a degree of facial asymmetry is present in all
individuals, there is a difficulty level in identifying this asymmetry.
This is usually because the soft tissues may compensate for the
underlying skeletal imbalances. in addition, there are reports that the
individuals may mask facial asymmetry by their posture9. For
example, tilting of the head may give the perception of no occlusal
cant in an individual with occlusal cant. Therefore ,it should always
be a priority to assess the craniofacial and dental asymmetry as a
part of clinical evaluation of the patients

109. • Recently the number of orthodontic patients who desire to
correct facial asymmetry and lip canting (LC)has
increased.1When setting the surgical treatment objectives for
orthognathic surgery, the prediction of soft tissue change is
difficult and inaccurate, especially in the frontal plane. Mild to
moderate LC can remain even after correction of skeletal
asymmetry by two-jaw surgery

111. The frontal occlusal plane is represented by
Frontal Occlusal Plane
a line running from the tip of the right canine
to the tip of the left canine. A transverse cant
can be caused by differential eruption of the
maxillary anterior teeth or a skeletal
asymmetry of themandible.
Patient with canted occlusal frontal planeand
unilateral posterior gingival smile.

112. This relationship of the maxilla to the smile cannot be
seen on intraoral images or study casts, and smile
photographs can also be misleading. Therefore, clinical
examination and digital video documentation are essen-
tial in making a differential diagnosis between smile
asymmetry, a canted occlusal plane, and facial
asymmetry. Having the patient bite on a tongue blade or
a mouth mirror in the premolar area during the clinical
examination is a good way to recognize an asymmetrical
cant of the maxillary frontal occlusal plane

113. Transverse deviations of the upper and lower incisal midpoints
should be measured and recorded. The roll of the maxilla can
be clinically determined by measuring, with a Boley gauge, the
vertical distances from each medial canthus to the ipsilateral
maxillary teeth . Right-left differences that are consistent
through the arch indicate canting (abnormal roll) of the upper
jaw. These measurements should be interpreted with caution
as they can be affected by local dental irregularities, vertical
eye dystopia, and yaw mal rotation of the upper jaw

115. Transverse cant of the maxilla can
be caused by differential eruption and placement
of the anterior teeth and by skeletal asymmetry of
the skull base and/or mandible resulting in a
compensatory cant to the maxilla. Intraoral images
or even mounted dental casts do not reflect the relationship
of the maxilla to the smile adequately.
Only frontal smile visualization permits the orthodontist
to visualize any tooth-related asymmetry
transversely.
Patient illustrating a maxillary
cant with the use of a tongue
spatula.

116. Smile asymmetry may also be caused by soft
tissue considerations such as an asymmetric smile
curtain. In the asymmetric smile curtain, there is
a differential elevation of the upper lip during
smile, which gives the illusion of transverse cant
to the maxilla.

117. This smile characteristic emphasizes
the importance of direct clinical examination in
treatment planning for the smile, because this soft
tissue animation is not visible in a frontal radiograph
or reflected in study models. It is not well
documented in static photographic images and is
documented best in digital video clips.
Contemporary orthodontists evaluate smiles in 3
dimensions: transverse, vertical, and sagittal. A fourth
dimension, time, should also be considered.

118. The smile arc is the relationship of the curvature
of the incisal edges of the maxillary incisors,
canines, premolars, and molars to the curvature of
the lower lip in the posed social smile .
(A–C) The ideal smile arc has the maxillary incisal edge
curvature parallel to the curvature of the lower lip
upon smile; the term ‘‘consonant’’ is used to describe this
parallel relationship. A nonconsonant or flat smile arc is
characterized by a maxillary incisal curvature flatter than the
curvature of the lower lip, and the reverse smile arc
follows a curve opposite to the lower lip.

119. Correction of canting
Because of mini-implants ,dental canting can
be corrected nonsurgically .
Dental or occlusal plane canting may be accompanied by
skeletal canting or soft tissue canting
Therefore , diagnosis , treatment planning and
determination of the horizontal reference line are
the critical factors in the correction of canting .
Canting , including eye – level canting , is the most
difficult situation to treat because the horizontal
reference line is difficult to determine; eye-level
canting is nearly impossible to correct.

120. .However ,centric relation mounting of casts can only allow visualization
of the dental problem on the basis of the position of the facebow .
To evaluate canting , it is necessary to examine not only the hard
tissue three – dimensionally while the patient is at rest and smiling .
Centric relation on mounted casts is also useful for
visualizing problems, as long as through clinical
examination of the face has been performed beforehand
.

121. Dental canting is generally accompanied by discrepancies
in the vertical and anteroposterior positions of the
molars .
If there are discrepancies in the molars , there are also
discrepancies in the canines .
For correction of canting , the anteroposterior position and
axes of the canines and molars should be corrected altogether
.

123. Canting is not a vertical problem only .
To correct frontal canting , the vertical positions of
the molars and the cusp tips ( second order
angulation ) of individual teeth should be corrected
.

124. Movement of the whole dentition can resolve the problem
.The maxillary right posterior teeth are comparatively
extruded .

125. Sectional mechanics are used to increase the rate of
tooth movement .

126. Clinical situation after canting correction by
unilateral intrusion .

128. For intrusion of the upper right buccal segment , microimplants were placed between the
maxillary right canine and first premolar and between the second premolar and first molar
Powe rchain was applied from the microimplants to the main archwire .

129. The maxillary occlusal cant was corrected after two months of
treatment .

130. Palatal root torque control is key for molar intrusion.
(a)It is possible to control torque by providing the moment
with the twisted wire and the bracket slot.
However , it is a statically indeterminate system , making
accurate control difficult and efficiency low .
It is also possible to control torque by applying a combination
of torque and constriction force .
(b)However, the use of crossarch splinting would be more
efficient .
(c and d )Use of buccal and lingual intrusive forces together is
the most effective protocol .

132. A 26-YEAR OLD WOMANPRESENTED WITH
ASYMMETRIC GINGIVAL EXPOSURE .
The smile photograph showed canting of the maxillary
occlusal plane.
The right anterior teeth were relatively extruded and there
was a difference in the height of the right and left canines.
Hence there was greater gingival exposure on the right side and
the upper dental midline was deviated to the left side .

133. Treatment objectives and plan
The patient refused surgical intervention ,and
treatment was planned around miniscrew implant
anchorage to intrude the right anterior segment.

135. Treatment
Both arches were bonded with .o22x.o28 preadjusted
fixed appliance and leveling and aligning started .
The archwires were progressively increased up to
.019x.025 stainless steel .
An OSAS miniscrew implant ( diameter 1.6 mm ,length 6.0 mm) was
placed in the inter radicular bone between the upper first and second
premolars on the right side .
An elastic thread was tied around the upper right anterior hook and
posteriorly to the second premolar and then to the miniscrew to apply
intrusive force .

136. The vertical distance between the
miniscrew and the archwire decreased
as the teeth were intruded .

137. The asymmetric gingival exposure improved with unilateral
intrusion of the upper right anterior segment via miniscrew
implant anchorage .
The increased elevation of the upper lip on the right
side remained after treatment .
Gingivectomy in the upper right lateral incisor and canine area would
have enhanced the esthetic outcome .