Orthodontic correction of occlusal plane canting part 1

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

Occlusal-plane canting is a challenging problem for
orthodontists because it cannot be solved easily without
surgical intervention. Normally, a LeFort I osteotomy and
concomitant mandibular surgery is used to correct the
problem, even in patients with mild facial asymmetry but
with noticeable occlusal-plane canting.
Patients illustrating a maxillary cant with
the use of a tongue spatula.

The cant of the occlusal plane in the frontal plane can be the result of skeletal
asymmetry of the jaw bones or the asymmetric vertical position of anterior
or posterior teeth. Before the advent of skeletal anchorage in orthodontics,
the correction of occlusal-plane canting had only limited indications, whether
the origin was skeletal or dental. Therefore, surgery was considered the only
method for correcting this problem. However, skeletal anchorage has made
possible true intrusion of molars, which was difficult with conventional
orthodontic means. Moreover, it is now possible to correct occlusal-plane
canting by controlling the vertical position of the molars

A , The pupillary and ear planes can usually be used as horizontal references. A perpendicular plane
through nasion can be helpful in assessing the left-to-right facial asymmetry. The asymmetry is
usually the least at the cranial base area and the greatest at the mandible and chin area, as seen in
this 45-year-old woman with a right mandibular condylar osteochondroma. B , Evaluate the smile.
This may emphasize the asymmetry. PP , Pupillary plane; EP , ear plane; Com , commissure plane; OP
, occlusal plane; IB , inferior border of mandible; FM , facial midline plane; CM , chin midline. C , The
profile view is helpful to determine AP and vertical facial balance. CFH , Clinical Frankfort horizontal
plane; SNP , subnasale perpendicular plane. D , A tongue blade placed transversely across the
occlusion demonstrates the vertical asymmetry and cant in the occlusal plane. E , The occlusion is
evaluated for vertical, transverse and AP asymmetry including midlines, cross-bites, occlusal cant,
open bites, yaw, and so on. UIM , Upper incisor midline; LIM , lower incisor midline
Diagnosis of occlusal canting in facial asymmetry

It was reported that all people have some craniofacial asymmetry, even in
esthetically normal or pleasing faces. In addition, an occlusal cant in most
normal patients might be too small to detect. Patients often recognize their
occlusal canting as being unpleasant esthetically when there is a discrepancy
in parallelism between the lip line and the occlusal plane
(a) Significant asymmetry of the lower face, with the mandible and chin point to the patients left, and transverse cant of the
rima oris (opening of the mouth) (left and right commissures at different vertical levels) and the inferior chin plane. (b)
Transverse cant of the maxillary
occlusal plane evident, canted down on the patient’s right. (c) Inferior view highlights asymmetry of the chin and lower lip in
relation to the upper lip. (d) Dental mirror handle held against the maxillary dentition demonstrates a transverse cant in
relation to
the interpupillary plane.

Measurement of occlusal cant in the maxilla. A, The magnitude
of occlusal cant by measuring the degree of canting relative to
the true horizontal. The reference lines for determining the cant
are as follows: a true horizontal represented by a tangent to the
normal
supraorbital rims (1) and a vertical line drawn through the crista
galli and upper third of the nasal septum (2). The degree of cant
is determined
with respect to the true horizontal. On this AP cephalogram, the
degree of canting of the occlusal plane was 6 degrees. B, The
magnitude
of occlusal cant can be measured by evaluating the medial
canthus-canine distance. In the patient above, the medial
canthus to right canine
distance was 62 mm; the distance to the left canine was 56 mm,
for a total vertical discrepancy of 6 mm.
Padwa et al reported that 4° is the threshold for
recognizing an occlusal cant. However, they measured
occlusal-plane canting from a horizontal line connecting
the supraorbital rim.

In some patients with vertical asymmetry of the right and left posterior teeth
without anterior occlusal-plane canting, the occlusal canting becomes obvious
after orthodontic leveling. Facial asymmetry that is too minimal for
orthognathic surgery but accompanies recognizable occlusal canting can be
corrected by skeletal anchorage-reinforced orthodontic treatment. However,
few biomechanical systems use skeletal anchorage to correct occlusal canting.

Fushima et al. (1989) examined
the vertical height of right and left posterior
teeth in cases with mandibular asymmetry by
the use of P-A cephalograms, and revealed that
the vertical height of posterior teeth on the
suppressed side of the mandible was lower than
contralateral teeth. These findings suggest that
occlusal deviations are related to facial growth.

In orthodontic diagnosis, the occlusal plane
represented by a line drawn from the midpoint
of the upper and lower central incisor edges to
the occlusal surface of the upper and lower first
molars on the lateral cephalogram should be
carefully evaluated. The cant of the occlusal
plane must relate to the sagittal inclination of
the condylar path and the guidance of lingual
concavity of the upper incisor (Dawson, 1989).

Sagittal condylar inclination is
defined as the angle between the protrusive path of
the condyle and usually the Frankfort horizontal, or
any other horizontal reference plane, such as in the
current study’s Camper’s plane.
Camper’s Plane •“A plane established by the inferior
border of the right or left ala of the nose and the
superior border of tragus of both ears” •

Transverse canting of the maxillary occlusal plane should be assessed
visually in frontal view with the aid of (a) photographic retractor sand
/or (b)orthodontic cheek retractors,and(c) with placement of a
wooden tongue spatula(or dental mirror handle)on the occlusal plane .

(a) Frontal view photograph showing assessment of cant of
occlusal plane in relation to interpupillary plane. (b) Frontal
view photograph showing true facial midline for documenting
facial asymmetry with deviation of mandible toward left side.
(c) Frontal view photograph illustrating cant of lower border of
mandible. (d) Submental view photograph documenting
mandibular asymmetry. (e) Superior (Bird’s eye) view
photograph.

UNILATERAL INTRUSION (VERTICAL
ASYMMETRY CORRECTION)
Clinical objective
• Asymmetrical intrusion of the maxillary or mandibular
teeth to level the occlusal plane and smile line.
Skeletal anchorage can be used in
patients with occlusal canting to reduce
the need for orthognathic surgery.

Treatment options
• Unilateral mini-implant intrusion, except where
contra-indicated in patients with a Class III skeletal
pattern or reduced lower anterior face height.
• Conventional anchorage involving asymmetric headgear.
• Hybrid functional (orthopaedic) appliance, but with a
reliance on asymmetric extrusive changes.
• Asymmetrical orthognathic surgical movements.
ACTIVATOR HEADGEAR

Relevant clinical details
• Unilateral or even bilateral asymmetric intrusion is
ideal for those patients with a predominantly vertical
asymmetry accompanied by an average or increased
maxillo-mandibular angle and Class II features. Full
bilateral treatment involves intrusion of teeth in
diagonally opposing quadrants (e.g. upper right and
lower left quadrants).
Class II malocclusion with accentuated occlusal
plane
inclination corrected with miniplate: a case report
Dental Press J Orthod. 2016 May-June;21(3):94-103

Relevant clinical details
• The incisor relationship (overjet, overbite).
• The maxillary and mandibular occlusal planes and
whether an occlusal cant is present.
• The upper incisors’ vertical display (on both passive
and smiling exposure) and the smile arc.

Biomechanical principles
• Simultaneous buccal and palatal mini-implant
anchorage in the maxillary arch ensures true vertical
movements within a quadrant, and avoids transverse
side-effects or the need for a modified TPA (which
allows differential molar movements). Since lingual
insertion sites have a low success rate then
mandibular intrusion utilises buccal mini-implants
only and requires transverse control using a full fixed
appliance.

• The mini-implants should be vertically positioned in
relatively apical sites, such that the buccal one is
Biomechanical principles
close to, or at the, muco-gingival junction. This
provides an adequate distance for effective traction,
especially as the adjacent teeth intrude towards the
implant head.
• Unilateral intrusion forces should be applied with a
rigid (0.019 × 0.025) steel archwire in place.

Simultaneous buccal and palatal mini-implant
anchorage in the maxillary arch ensures true
vertical movements within a quadrant, and avoids
transverse side-effects.

Clinical tips and technicalities
• Consider removal of erupted third molars
(prior to
orthodontics) in the quadrant(s) where molar
intrusion is required.
• Bond the second molars, where erupted, in
the
quadrant requiring intrusion.
• In vertical correction cases, monitor the
occlusal
plane by measuring the overbite involving the
incisors and canine teeth, and their vertical
display
relative to the lip level. Also, monitor lateral
openbites and hence the need for extrusion of
the
opposing teeth or additional intrusion in the
diagonally opposite quadrant.

Mid-treatment problems and solutions
• Vertical side-effects such as a rollercoaster buckling
of the arch and lateral openbite:
Ensure that the second molars are bonded when
fully erupted.
Avoid the application of traction with a flexible
archwire in situ.
Vertical settling elastics may be used to close a
lateral openbite by extrusion of the opposing arch.
The elastics may be connected either to the
mini-implant anchored teeth or directly to the
mini-implant head. The latter avoids any risk of
extrusive relapse of the intruded teeth.

The roller coaster effect is observed when a wire of low
strength such as NiTi is used for canine retraction
NiTi deos not have the strength to remain rigid when a retracting force such as an elastic chain is
stretched from the molar to the canine.
The molar and premolar crowns tend to tip mesially and extrude distally.
The flexible Niti then bends gingivally and as a result tends to tip the canine crown distally .
The orientation of the canine bracket when the crowns tips distally tends to extrude the
incisors and deepen the bite
In short ,the canine occlusal plane goes for a toss and when we follow the occlusal plane from
the right molar to the left molar it resembles a roller coaster and hence the name is used

Clinical steps for unilateral intrusion
Pre-insertion
1. Determine the insertion sites, e.g. a buccal one between
the maxillary premolars and a palatal one
between the molars, prior to bond-up. The insertion of both
buccal and palatal mini-implants in the same
interproximal space should be avoided. Instead, the palatal
mini-implant should be in a more distal site
than the buccal one, since more molar interproximal space
is available on the palatal aspect.
2. This pre-planning enables active divergence of adjacent
premolar roots to be undertaken, to allow for
both ease of buccal mini-implant insertion and subsequent
vertical tooth movements. For example,
diverge the premolar roots by adding mesial and distal tip
to the first and second premolar brackets,
respectively. Remember that these tip alterations can
readily be corrected at the treatment finishing
stage.

Insertion timing
Determine this relative to the fixed appliance bond-up, by deciding
how much arch alignment is appropriate before mini-implant
insertion. Crucially, if there is insufficient interproximal space at the
planned insertion site then consider a preliminary phase of fixed
appliance treatment in order to diverge the roots and hence facilitate
mini-implant insertion . This is achieved by bonding the bracket(s)
with a modified tip, especially adding mesial tip to the normal second
premolar bracket orientation . Indeed, I routinely perform this step
prior to the majority of buccal insertions since it is a simple process
which can make mini-implant treatment much easier. The bracket
position is then corrected during the fixed appliance finishing stage
(after explantation). Furthermore, it may be biomechanically
beneficial to align the full arch such that it is ready to accommodate a
rigid (e.g. 0.019 × 0.025 stainless steel) archwire and powerarm by the
time of mini-implant insertion. This helps with sliding mechanics and
the reduction of unfavourable vertical side-effects.

(a) A pre-treatment panoramic, and (b) pre-insertion 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
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

Pre-insertion
3. Align and level the whole arch or initially only the segment(s) due for
intrusion. This depends on whether
there is a vertical discrepancy between the anterior and posterior teeth,
where a large step favours
segmental mechanics; whilst the risk of occlusal interferences from
displaced anterior teeth necessitates
full arch alignment.
4. Expand the maxillary arch where necessary to facilitate arch coordination
(following subsequent
mandibular autorotation).

Pre-insertion
5. Include bonded tubes on the second molars, if fully erupted, early in
treatment. If the second molars are
not fully erupted then do not bond them during initial alignment. Remember
to avoid molar bands in order
to facilitate effective gingival hygiene at the posterior limit of the dental
arch where a reduction in crown
height may occur and toothbrush access is most limited.
6. Once a 0.019 × 0.025 NiTi archwire has been inserted then book two
clinical appointments if a stent is to
be fabricated (which is especially valuable for palatal site guidance).

Pre-insertion
7. At the preparatory appointment take an alginate impression
for a guidance stent if desired. Palatal stents
do not require an accurate buccal alveolar impression, but
remember not to wax out the brackets adjacent
to a buccal insertion site.
8. Take periapical radiographs or a sectional CBCT to evaluate
the positions of the roots adjacent to the
insertion sites, either at the preparatory stage (when stent
usage is planned) or at the start of the
insertion appointment.
E) implantation planning on
maxilla,
(A) 3D-image reconstruction of the dentition, (B)
virtual implant planning in Simplant software,
The surgical stents fabricated
by the SurgiGuide System.

Mini-implant selection
9. Maxilla: use 1.5 mm diameter, 9 mm length mini-implants (for
Infinitas), with short and long necks on the
buccal and palatal alveolar sides, respectively. However, if the palatal
tissues are particularly thick or the
patient is still undergoing considerable somatic growth, then a 2 mm
diameter version may be indicated to
give maximum primary stability without relying on full depth intra-bony
insertion.
10. Mandible: body length selection depends on the anticipated cortical
depth and density such that a long
length (9 mm) version is preferable for adolescent patients, where the
cortical bone is immature. An
Infinitas 1.5 mm diameter, 6 mm length, short neck version may be used
in an adult.

Insertion
11. Superficial anaesthesia of the insertion sites, e.g. blanch the
overlying mucosal area with a local
anaesthetic injection, especially in the palatal site, although topical
anaesthetic alone may be sufficient in
the buccal site.
12. Fit the stent (where applicable).
13. Use a mucosal punch for palatal insertions. Temporarily remove
any stent, after the surface has been
marked with it in situ, so that the mucotome can be applied
perpendicular to the surface, providing a
clean cut of the tissue. If necessary, then remove the mucosal tissue
with a mosquito forceps and/or
Mitchell’s trimmer.

14. In adults, use a cortical bone punch to perforate the relatively
dense thick palatal and mandibular cortex.
15. Insert buccal and palatal maxillary, and buccal mandibular mini-
implants, according to the treatment plan.
Remember to use a speed-reducing (e.g. 128:1 ratio) contra-angle
handpiece at less than 100 rpm for
palatal sites.
16. The buccal insertion sites should be at or close to the muco-
gingival junction and the vertical angle of
insertion should be perpendicular to the bone. These details enable
reliable attachment of the traction and
a maximum range of intrusion movement.
cortical bone punch
speed-reducing (e.g. 128:1
ratio) contra-angle

17. Take an intra-oral radiograph if close root proximity is
clinically suspected (due to pain sensation on
percussion of an adjacent tooth).
18. Complete insertion to the point that the mini-implant
neck is partially submerged but the head is fully
accessible.

Post-insertion
19. Insert a 0.019 × 0.025 steel archwire.
20. Bond attachments (buttons or cleats) to the palatal
surfaces of the crowns adjacent to any palatal
mini-implants.
21. Apply approximately 50 g (elastomeric chain) traction
for the first four to six weeks. This utilises the
palatal attachments and the simplest configuration is a
‘V’ one, where the traction component’s ends are
attached to the teeth and its mid-section engages the
mini-implant head.

On the buccal side, the traction
may be applied directly to the adjacent brackets or around the
archwire. Following the initial healing
period, stronger (150–200 g) elastomeric or closing coil
auxiliary traction should be used.

22. Monitor treatment progress by
recording the following features at the
start of intrusion and at subsequent
appointments: overjet, AOB/overbite,
canine relationship, the upper incisor
display (at rest and on full
smiling), occlusal cant and presence of
any molar openbite.
23. Monitor the periodontal condition
(probing depth) of the terminal molars.

24. Consider over-correction of the
intrusion changes to allow for possible
relapse and/or keep the miniimplants
in situ until it is clear that further
anchorage is not required.
25. Consider an initially intensive
retention regimen, e.g. three months
full-time wear of plastic retainers with
whole arch occlusal coverage. These
should prevent early molar extrusion
after debond.

UNILATERAL INTRUSION EXAMPLE
• A 28 year old female presenting with a Class II division 2 malocclusion on a skeletal I base with
an average
MMPA . She had predominantly vertical dentofacial asymmetry with the maxillary plane
canted downwards on the left side and more gingival display on this side on full smiling (although
she
camouflaged this by habitually smiling by only a limited extent). All first premolars plus a lower
incisor were
absent, and unsuccessful surgical recontouring of the maxillary gingival margin had previously
been
performed.
( a–c) Pre-treatment views where the patient’s habitual smile camouflages her vertical maxillary cant and gingival
level asymmetry. The Class II division 2 malocclusion is shown with absence of upper first premolars and a lower
incisor

UNILATERAL INTRUSION EXAMPLE
The maxillary arch was levelled and aligned to
accommodate a 0.019 × 0.025 steel archwire.
d–h) Left-sided intrusion commences with a 0.019 × 0.025 steel archwire in situ. Elastomeric traction
is applied to the brackets
and palatal cleats from mini-implants sited buccal and mesial to the maxillary left first molar, and
palatal and distal to this first
molar

A 1.5 diameter, 9 mm length mini-implant was then
inserted on both sides of the left maxillary alveolus:
mesio-buccal and disto-palatal to the first molar (Figs
10.3f–h). Elastomeric traction was applied buccally to
the upper left premolar bracket and molar tube, and
palatally to buttons on the palatal surfaces of the
molars.

Both the malocclusion and smile aesthetics were improved
by five months of intrusion prior to bonding the
lower fixed appliance . Notably there was more vertical
clearance for the left molars, although
it appeared that these may have undergone some
compensatory eruption.
(i–k) the maxillary cant is levelling and the lower arch is being aligned, with relatively gingival
bracket positions in the
lower left quadrant to assist with vertical compensation and overbite reduction.

After a further four months the maxillary and
mandibular planes and smile line were level .
Intrusion was continued for some over-correction
and any consequent left lateral openbite would be
corrected by lower left molar elastic extrusion
(given the originally deep overbite).

CENTRELINE CORRECTION EXAMPLE
This 27 year old female presented with a Class II division 2
malocclusion on a mild skeletal II base.
She had transverse skeletal asymmetry with the chin point
displaced to the left side (without a
functional displacement) and a subtle degree of vertical
asymmetry (occlusal cant slightly higher on the left
side).

The upper incisor–lip relationship was aesthetically satisfactory. The upper right
canine and the first
premolars from the other three quadrants were absent. The upper and lower
dental centrelines were
displaced to the right and left sides, respectively, and the buccal segments
exhibited similar asymmetry,
including a ¾ unit Class II relationship of the left canines.
(a–d) Pre-treatment
views showing this
Class II malocclusion
with absence of the
upper right canine and
first
premolars in the other
three quadrants,
asymmetric buccal
segment relationships
and centreline
discrepancies

CENTRELINE CORRECTION EXAMPLE
Both arches were initially levelled and aligned. The left Class
II canine relationship, deep overbite and lower
centreline problems were additionally corrected by the use of
pushcoil to re-open the lower left first
premolar space.
(e–g) The lower
left premolar space has re-opened during alignment and lower centreline correction. Upper posterior and lower anterior miniimplants
are being used for upper centreline correction and lower molar protraction, respectively. Indirect anchorage is used to
provide a horizontal vector of traction from a 0.019 × 0.025 steel auxiliary wire (connected vertically between the archwire and
mini-implant head).

This was followed by asymmetrical traction, predominantly
Class III elastics on the right side, although a
small residual centreline discrepancy was accepted due to
tooth size discrepancies .
Debond views

Use of rhythmic wire system with
miniscrews to
correct occlusal-plane canting
Yoon-Goo Kang, Jong-Hyun Nam, and Young-
Guk Park
Seoul, Korea
American Journal of Orthodontics and Dentofacial
Orthopedics Kang, Nam, and Park 541
Volume 137, Number 4

A biomechanical system was developed called
“rhythmic wire,” which consists of 2 miniscrews (on the
maxillary and mandibular teeth), intrusion wire,
extrusion wire, transpalatal arch, and lingual arch. This
report presents the use of this method in 2 patients for
correcting the occlusal cant to avoid or minimize
orthognathic surgery

Rhythmic wire
Rhythmic wire was initially developed to control the vertical position of the
posterior teeth and consists of intrusion rhythmic wire and corresponding
extrusion rhythmic wire. In addition, a transpalatal arch or a lingual arch can be
applied if there is a need to control the third-order torque of posterior teeth
that face an intrusion or extrusion force. Rhythmic wire can also be a good
option for patients with palatally or lingually tipped posterior teeth because
buccal tipping of the teeth can occur without a transpalatal or lingual arch.
Intrusion rhythmic wire: upper, schematic diagram of the
intrusion rhythmic wire; lower, after placemen

The intrusion wire is formed with 0.019 × 0.025-in beta-titanium alloy
straight wire of appropriate length (usually the length between the
first premolar and the second molar) with hooks on each end for
engagement to the main archwire

If a decrease in the intrusion force is required, the size of wire can be reduced,
or helices can be included. There is no consensus on the optimal force for the
intrusion of teeth, but there appears to be some accord between researchers
that posterior teeth require more force than anterior teeth. Kalra et al used 90
g of force per posterior tooth, Park et al suggested 150 to 200 g, Umemori et al
recommended 500 g, and Melsen and Fiorelli used 50 g buccolingually per
posterior tooth. The intrusion wire is placed on the vestibular side of the
miniscrew, which is generally placed between the second premolar and the
first molar, and each end is activated to engage the main archwire .

The point where the hooks of the intrusion rhythmic wire engage
depend on the clinical need; this means that the clinician can choose the
site to apply the force and change the site by adjusting the intrusion wire
without replacing the miniscrew. The miniscrew should have an undercut
in its head design to place the intrusion wire, and an elastomeric ring can
be used to secure the intrusion wire to the miniscrew.

The extrusion rhythmic wire, which is placed on the opposite dentition, is
made from stainless steel wire (or cobalt-chromium wire with heat
treatment) in a clover-like form . An indentation is prepared on the top half
circle (vestibular side) to accept the miniscrew head, and each root (occlusal
side) has a hook for attachment to the main archwire.
configuration and activation
Extrusion rhythmic wire: upper, schematic diagram of the
extrusion rhythmic wire; lower, after placement
Clover
Plants

Activation is achieved by manipulation of the horizontal loops. A
smaller force than for intrusion is sufficient for extrusion of the teeth.
However, to prevent deformation of the wire, its size should be
greater than 0.016 in, and stainless steel wire is recommended.
Helices or loops can be added to reduce the force .

Modifications of the rhythmic wire: left, a helix was included in the
intrusion wire to reduce the force; right, loops were added to the
extrusion wire to reduce the force
The intrusion and extrusion rhythmic wires should be used
simultaneously to maintain the integrity of the occlusal contacts. In
addition, the position of the hooks is determined by the clinical situation

The extrusion or intrusion of molars from the buccal side can cause buccal or
lingual crown tipping, which is generally undesirable. To minimize this tipping, a
transpalatal or lingual arch can be applied with a rectangular lingual sheath to
the active (extrusion or intrusion) side, and a round sheath can be applied to
the other side, as described by Rebellato. Also, full alignment, leveling, and
space consolidation are recommended before applying a rhythmic wire, and
the main archwire should be rectangular stainless steel for more predictable
and easy control of the posterior quadrant

Patient 1
A 20-year-old woman was referred from a local dental clinic complaining of masticatory
problems on the left side. The intraoral features showed moderate crowding of her maxillary
dentition, an anterior edge-to-edge bite, and a posterior crossbite on the left side . The
occlusal relationship was Class II molar and Class I canine on her right side, and Class III molar
and canine on her left side . Her maxillary right posterior teeth were positioned vertically low
compared with the left side . After reviewing her condition, she was diagnosed with skeletal
Class III facial asymmetry and a canted posterior occlusal plane.

Her skeletal problems were mild, and she did not require facial changes. She refused
surgery and also declined treatment accompanying the extraction of her premolars. The
treatment plan was established to distalize the maxillary right posterior and mandibular
left posterior teeth with miniscrews to resolve the crowding and correct the occlusal
relationships with rhythmic wire
upper row, pretreatment study model. Note the difference in the vertical heights of the molars between the left
and right sides; middle and lower rows, application of the rhythmic wire system

After distalization of the molars, aligning and leveling were performed. The leveling procedure
unmasked the posterior occlusal canting and showed an apparent difference in the gingivae
between the left and right sides while smiling . It was decided to intrude the maxillary right
posterior teeth because of the excessive gingival display on the right side. Miniscrews were placed
between the maxillary right second premolar and molar, and between the mandibular right
second premolar and molar. An intrusion rhythmic wire was placed on the maxillary right
posterior teeth, and an extrusion wire was placed on the mandibular right posterior teeth. In
addition, a transpalatal arch and a lingual arch with a rectangular lingual sheath were applied on
the right side, and a round sheath was used on the left to control the inclination of the teeth

The occlusal cant was corrected by the intrusion of the maxillary right posterior teeth. Finishing and
detailing of the occlusion was then performed, and the intruded maxillary right posterior teeth
were maintained with wire ligation to the miniscrew. After removing the appliances, a canine-to-
canine lingual bonded retainer was placed in the maxilla, and a wraparound retainer was used for
the mandible. Superimposition of pretreatment and posttreatment lateral cephalogms showed
reductions of the difference in vertical height of the right and left molars .
Pretreatment and posttreatment cephalograms and superimposed tracings of patient 1: black line, pretreatment; red line, posttreatment. The
difference in vertical height of the molars was reduced mainly by intrusion without remarkable changes in the mandibular position

Distalization of the molars and leveling took 15 months, correction of the
occlusal cant with rhythmic wires took 9 months, and finishing took 4 months.
Overall, the total active treatment period was 28 months

PATIENT 2
A22-year-old womanvisited the orthodontic department
of Kyunghee University complaining of crowding
of her maxillary teeth and protrusion of her lips. The intraoral
examination showed maxillary and mandibular
anterior crowding, and the facial examination showed
a canted occlusal plane with asymmetric elevation of the
right and left corners of the mouth during smiling that
exaggerated the occlusal canting (Figs 7 and 8).

upper row, pretreatment study model; middle and lower
rows, application of the
rhythmic wire system.
The
treatment plan was to extract the first premolars to resolve
the crowding and lip protrusion and to apply rhythmic
wire to correct the occlusal canting.

After the conventional aligning and leveling, and closure
of the extraction site with retraction of the anterior
teeth, rhythmic wire was applied to the right side of her
dentition. The application side was determined by the
amount of gingiva showing.Her occlusal canting was corrected
after 4 months of rhythmic wire application.

As with patient 1, a canine-to-canine lingual bonded retainer
was placed on themandibular dentition, and awraparound
retainer was used for the maxillary dentition. The total
treatment duration was 18 months, which included 12
months for aligning, leveling, and anterior retraction; 4
months for correcting the canting; and 2months for detailing.
Smile photos of patient 2. From left, pretreatment, midtreatment, and after rhythmic wire
application. Occlusal canting before treatment was corrected.

Superimposition of pretreatment and posttreatment
lateral cephalograms showed reduction of the difference
in vertical height of right and left molars .

RESEARCH AND REVIEWS: JOURNAL OF DENTAL SCIENCES
Miniscrews: Clinical Application of
Orthodontic.
Abu-Hussein Muhamad, and Watted Nezar.
RRJDS | Volume 2 | Issue 3 | July - September, 2014

Miniscrew-assisted multidisciplinary
orthodontic treatment with surgical
mandibular advancement and
genioplasty in a brachyfacial Class II
patient with mandibular asymmetry
Vanessa Paredes-Gallardo,
Veronica Garcıa-Sanz, and
Carlos Bellot-Arcıs
Valencia, Spain
November 2017 Vol 152 Issue 5
American Journal of Orthodontics and
Dentofacial Orthopedics
After periodontal treatment, miniscrews
were placed to correct the occlusal plane canting and the excessive curve of Spee with orthodontic treatment.
The surgical treatment plan consisted of a bilateral asymmetric sagittal split osteotomy for mandibular
advancement and genioplasty.

Clinical applications of the
Mini-Screw-Anchorage-System (M.A.S.)
in the maxillary alveolar bone
Aldo Carano, Stefano Velo,
Cristina Incorvati, Paola Poggio*
PROGRESS in
ORTHODONTICS
2004; 5(2): 212-230

The correction of a canted occlusal plane is easily obtained with the mini-screws as skeletal
anchorage. The miniscrew is used as anchorage to intrude the extruded canines and the
laterals on the side of the cant. In this case the screw was centered between the roots of the
maxillary canine and first premolar (a). After correction of the occlusal plane and of the dental
midline (b).
The correction of a canted occlusal
plane is often considered
an impossible objective with traditional
orthodontic mechanics.
With the mini-screws as skeletal
anchorage this objective can be
achieved more predictably.

mini-screws are placed in between
the upper laterals and the
canines or in between the upper
canines and the bicuspids for the
maxillary arch and in between
the laterals and the canines for
the mandibular arch.

The miniscrew
is used as anchorage to
intrude the extruded canines and
the laterals on the side of the
cant, and to center the dental
midline. During the
intrusive movements, it is very important
to center the mini-screws
in between the roots of the teeth
that need to be intruded in order
to avoid the interferences between
the teeth and the screw.

Iatrogenic Sequela of Orthodontic Treatment
Katja Kritzler, DDS, postgraduate student 1
Ulrich Kritzler, DDS, Dr. med. dent., FZA für Kieferorthop‫ن‬die 1
1 Private practice of orthodontics, Münsterstr. 25, D-48231 Warendorf,
Germany
Working Paper · December 2015
DOI: 10.13140/RG.2.1.2709.7688/2
Side effect of indiscriminate levelling of the upper arch: development
of a canted plane of occlusion.

The class II elastics that are often used to correct a
class II malocclusion, so-called class II mechanics, could
cause the downward and backward rotation of the OP
due to mandibular molar extrusion and maxillary incisor
extrusion , consequently, increased the angle of the
OP with SN plane. Zimmer et al. also observed
several significant changes in the occlusal plane inclination
due to oppositely guided intermaxillary elastics,
the induced shift with class II elastics was clockwise,
while class III elastics was counterclockwise.
Progress in Orthodontics 2014, 15:41
Changes of occlusal plane inclination after
orthodontic treatment in different dentoskeletal
frames
Jin-le Li Chung How Kau and Min Wang

According to Burstone and Choy unwanted side effects will occur when
a continuous NiTi arch is used in a unilateral or bilateral high canine case.
They pointed out that the canine will be extruded but the posterior adjacent
teeth will be intruded and tip mesially and the anterior adjacent teeth will
be intruded and tip distally. They concluded that the intrusive force on the
premolar will finally produce a large counterclockwise rotation on the
ipsilateral molar which will tip the posterior teeth mesially.
A) Straight wire mechanics used for
canine extrusion. B) Note the side effects on the
lateral incisor and first premolar, which made the
conditions of the case worse.

Traction of tooth with self-ligating brackets. A) With NiTi archwire attached to all
teeth. Deleterious effects on adjacent teeth (intrusion and buccal inclination,
especially in the lateral incisor); B) procedure carried out to minimize deleterious
effects on adjacent teeth supported by an rigid arch (the intrusive effects on
adjacent teeth exist, but do not result in effect on the teeth due to the use of the
rigid arch).

After consistent alignment of the brackets and teeth is accomplished, a
straight 0.019 x 0.025-inch stainless steel rectangular wire should be fitted
into all brackets except the canine bracket. The heavy ground arch will be
bypassing the high canine which is aligned by a second „piggy-back“
continuous NiTi arch from the molar auxilliary tube to the contralateral
molar auxiliary tube.

The NiTi archwire should be tied initially only to the
canine and to the ground arch at the midline. Its force can be increased by
tying further distally on the anterior segment. Although anchorage should
be good with a stiff bypass arch , the extrusion force on the canine should
be kept low using a NiTi arch with small diameter like 0.010 in or 0.012 in

The NiTi wire goes through a
auxilliary slot in the bracket
It works by trying to get back to its original stretched out state,
thereby pulling on the impacted tooth. To get the pull effect
though, the ends of the elastic wire have to be able to run freely.

A sectional piggyback NiTi wire is engaged in
the maxillary left canine
Double L LOOP to align highly placed maxillary canine
(a) Auxiliary T-loop (0.0175 × 0.025

Canine bypass archwire. (a) Before
canine root movement. (b) After treatment.
Undesirable effects are eliminated
on the adjacent teeth.
The Biomechanical Foundation of Clinical Orthodontics
Author(s)/Editor(s): Burstone, Charles J.; Choy, Kwangchu
Canine bypass archwire

.
A cantilever canine root spring during partial lingual treatment. (a)
Before canine root movement. (b) After root movement. (c)
Occlusal view. The canine is tied back using elastics on the lingual
side to prevent mesial movement. The force system of the root spring
produced a desirable moment, and the extrusive force helped to erupt
the canine that was in infra-occlusion (red arrows in a).
The Biomechanical Foundation of Clinical Orthodontics
Author(s)/Editor(s): Burstone, Charles J.; Choy, Kwangchu
Cantilever for canine extrusion

Cantilevers (0.017-inch x 0.025-inch CNA) were
placed bilaterally from the auxiliary tube of the
molar bracket to bring the highly placed canines
into the arch ..
Further alignment
of the canines was done using a 0.016-inch nickeltitanium
(Ni-Ti) wire piggybacked over a stiffer
0.017-inch x 0.025-inch CNA base archwire
The Biomechanical Foundation of Clinical OrthodonticsAuthor(s)/Editor(s): Burstone, Charles J.; Choy, Kwangchu

Cantilever for canine extrusion.
by means of SAT, the desired
movement is achieved when force is directly applied
to the mal-positioned/impacted tooth, while reactive
force is dissipated or controlled in the posterior anchorage
unit as a result of an increase in the number
of teeth joined to the segment and/or the use of an anchorage
appliance.
Segmented arch or continuous arch technique?
A rational approach
Dental Press J Orthod. 2014 Mar-Apr;19(2):126-41

A) System of forces produced by a cantilever (statically determined
system).This system also reveals a tendency towards palatalization of
#13 with force going in the vestibular direction of CRes. B) Palatal bar used
to control any undesired effects on the anchorage unit.
- System of forces produced by a rectangular loop (statically undetermined
system). The activated rectangular loop (light blue) must be adjusted
so as to determine the final position of the tooth. When inserted into the slot
(dark blue), its deactivation will move the tooth in the previously established
position.
A cantilever can be described
as a segment of a stainless steel 0.017 x 0.025-in wire
or a β-Ti wire inserted inside a bracket or tube in the
reactive member, tied to the opposite end by means of
contact point in the active member (impacted or malpositioned
canine).

Therefore, the wire is not inserted
into the bracket slot where movement is desired. Should
the force produced by an activated cantilever (ranging
from 40 to 60 gf) be directed along the CRes of the
tooth, it will produce a translatory movement. Should it
bypass the CRes of the tooth (in most cases, it is applied
to the crown), it will result in a rotational tendency of
force due to the moment of force established

Conversely, given that the wire has been inserted
inside the bracket slot or tube, a force of equal intensity
and opposite direction is observed in the reactive member.
Similarly, a torque is produced inside the appliance
when the moment arm of the activated cantilever is
tied to the tooth to be moved. Such torque produces
movement that, in association with force, must be restricted
or reduced to nothing by reinforcing the anchorage
of the reactive member (for instance, by using a
palatal bar), so as to avoid side effects on the mechanics.

Class II malocclusion with accentuated occlusal plane
inclination corrected with miniplate: a case report
Marcel Marchiori Farret, Milton M. Benitez Farret
Dental Press J Orthod. 2016 May-June;21(3):94-103
The introduction of skeletal anchorage has increased
the number of treatment options for those cases with occlusal plane
inclination.
Mini-implants or miniplates may aid intrusion of a
group of teeth, either in the maxillary or mandibular
arches, without adverse effects while greatly reducing
total treatment time.

CASE REPORT
Diagnosis and etiology
A 29-year-old woman sought orthodontic treatment,
complaining about an unesthetic smile due to occlusal
plane inclination and midline deviation. This was caused
by absence of maxillary left lateral incisor and mandibular
left second premolar, with ankylosis of deciduous molar
in this region. Facial analysis revealed good symmetry and
vertical balance of the facial thirds, a convex profile, and
accentuated occlusion plane inclination in a smiling photograph.

Intraoral analysis revealed Angle Class II,
Division 1 malocclusion, with absence of maxillary left lateral
incisor, a peg-shaped maxillary right lateral incisor and
the presence of mandibular left deciduous ankylosed second
molar, which caused asymmetry on this side in both
maxillary and mandibular arches (Figs 2 and 3).

Maxillary
midline was deviated 2 mm to the left while mandibular
midline was deviated 2 mm to the right. Panoramic and
periapical radiographs confirmed the absence of maxillary
lateral incisor and mandibular second premolar and also
revealed mandibular teeth greatly inclined towards the ankylosed
deciduous molar. Initial lateral cephalogram and
cephalometric tracing revealed skeletal Class II malocclusion,
with upright maxillary incisors and well-positioned
mandibular incisors .

Treatment objectives
The objectives of treatment were as follows:
1. Correct occlusal plane inclination.
2. Obtain molar Class I relationship on the left side
and Class II on the right side.
3. Establish canine Class I relationship on both sides.
4. Correct midlines.
5. Extract deciduous molar and replace the tooth
with implant-prosthetic rehabilitation.
6. Open space in order to implant a prosthetic rehabilitation
of the maxillary left lateral incisor.

Orthognathic surgery was considered for occlusal
plane correction, but the patient refused this option.
Therefore, two other alternatives were considered
to correct Class II malocclusion and tooth absences.
The first option was to extract the maxillary right lateral
incisor, replace lateral incisors with canines, and
then replace canines with first premolars. This option
was rejected in a meeting with the dentist responsible
for the final rehabilitation.

The dentist believed that
the esthetic result would be better with implant-prosthetic
rehabilitation of the maxillary lateral incisor, as
maxillary canines had large crowns and were too different
in color, so as to be used as lateral incisors. The
second option was to extract maxillary right first premolar
and insert a mini-implant or miniplate on the
left side to move the maxillary right dentition posteriorly.

This option was rejected by the patient due to
longer treatment time required in comparison to that
for first premolar extraction to distalize all teeth. Thus,
in agreement with the patient and the other dentist, it
was decided to correct the occlusal plane by means of a
miniplate on the maxillary left side, extract the maxillary
right first premolar and open space for rehabilitation
of the maxillary left lateral incisor.

Treatment progress
Treatment began with the bonding of 0.022 × 0.028-in
standard Edgewise brackets on both arches, followed by
alignment and leveling with 0.012 and 0.014-in Nickel-
Titanium archwires and from 0.014-in to 0.020-in stainless
steel archwires. Thereafter, maxillary right first premolar
and mandibular left second deciduous molar were
extracted and maxillary anterior teeth were moved to the
right, tooth by tooth, with elastomeric chains, in order to
correct maxillary midline and open space, thus allowing
the insertion of an implant in the space left by the maxillary
left lateral incisor.

On the maxillary left side, after
correction of premolars rotation, a 2-mm space was created
and both premolar and canine were distalized with
elastomeric chains to increase the space for implantation
of the maxillary left lateral incisor prosthesis and to partially
correct Class II. On the mandibular arch, an implant
was inserted into the space of the missing premolar
to aid mandibular midline correction.

That implant
was positioned above the proper position, considering
that after occlusal plane correction with maxillary intrusion
and mandibular extrusion on this side, the implant
would be in adequate vertical position. Likewise,
the implant was positioned closer to the mandibular left
first molar and away from the left first premolar, thereby
allowing distalization of mandibular left molars and
distalization of mandibular anterior teeth, thus correcting
the midline.

After that, a miniplate in the shape of
an Y was inserted in left zygomatic buttress and used to
intrude all maxillary left teeth, with elastics connected to
0.019 × 0.025-in wire segments inserted into a tube and
connected to a miniplate, generating a force of 200 g/f
each .

Furthermore, the miniplate was used to distalize
all teeth on the left side, with elastomeric chains
connected to a hook welded between the lateral incisor
and canine, so as to correct Class II relationship. After
correction on the maxillary arch, the mandibular arch
was extruded with intermaxillary 1/8-in elastics connected
directly to the miniplate and on the mandibular
teeth and archwire (Fig 6).
(C and D) elastic mechanics employed to extruded mandibular left teeth,

E to G) after mandibular extrusion, (H to J) after miniplate
removal and during the finishing procedures.

In order to allow mandibular
teeth extrusion, the mandibular arch was made bypassing
the bracket of provisory crown over the implant.
At that time, the space for maxillary left lateral incisor
was already well defined and the implant was inserted.
Maxillary right lateral incisor was provisionally restored
with composite resin before appliance debonding, so as
to precisely define the spaces on the anterior region. After
34 months of treatment, the appliance was removed.
(C and D) elastic mechanics employed to extruded mandibular left teeth,

Treatment results
At the end of treatment, we noticed an improvement
in smile esthetics due to correction of occlusal plane
inclination and because the midlines were coincident
with the facial midline .
The profile remarkably
improved as a result of counterclockwise rotation of the
mandible, which reduced convexity, thus increasing the
prominence of lips and chin .

Intraoral and dental
casts analyses revealed that Class I molar relationship
on the left side, Class II molar relationship on the right
side and Class I canine relationship on both sides were
all obtained, with good intercuspation.

Panoramic radiograph showed good parallelism among
roots, in addition to root resorption on maxillary left
central incisor, which will be monitored after treatment.
Post-treatment lateral cephalogram, cephalometric
tracing and superimposition examinations confirmed
accentuated mandibular counterclockwise rotation

Furthermore, maxillary left molars were
intruded while mandibular molars were uprighted and
extruded. Maxillary and mandibular incisors were proclined
after treatment. The patient will be monitored
every six months in order to have root resorption and
treatment stability controlled.

Orthodontic correction of occlusal plane canting part 1

Orthodontic correction of occlusal plane canting part 1

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Orthodontic correction of occlusal plane canting part 1

Similar to Orthodontic correction of occlusal plane canting part 1 (20)

More from MaherFouda1

More from MaherFouda1 (20)

Recently uploaded

Recently uploaded (20)

Orthodontic correction of occlusal plane canting part 1