Management of low angle case in orthodontics

Management
of
low angle case
1
Dr Ravikanth Lakkakula

Contents
1. Introduction
2. Etiology
3. Clinical and Diagnostic Features
4. Management
A)Removable Appliances
B)Growth Modification Methods
C) Magnets
D)Fixed Appliances
E)Implants.
F)Bite Plate Effect (lingual appliance).
G)Invisalign virtual bite ramps.
H)Surgical Treatment
5. Stability and Retention
6. Conclusion
7. References
2

Introduction
Hypodivergent faces means short face or low angle case.
Skeletal Deep bite is one of the frequently seen malocclusions, occur
along with other associated malocclusions. It is said to be one of the
most perpetuating and damaging malocclusions . It may jeopardize the
periodontal support, occlusion itself or TMJ.
The excessive overbite is a complex orthodontic problem that may
involve a group of teeth or whole dentition, alveolar bone, of maxillary
and mandibular basal bones and / or soft tissue of the face . The
management of this problem demands a careful diagnostic analysis,
treatment plan and selection of appropriate treatment therapy.
3

Overbite is related to the growth of the jaws and the rate of eruption of
incisor teeth. It decreases from the primary dentition to the permanent
dentition by the upper and lower first permanent molars eruption .
Proprioceptive response conditions the patient against biting on this
natural bite opener, and thus the deciduous teeth anterior to the first
permanent molars erupt, thus reducing the overbite.
The short anterior vertical facial height type with a low mandibular
plane and the most extreme incisor overbites are those that would best
benefit from mandibular rotation, but their strong musculature function
resists the molar extrusion .
4

The skeletal deep bite is characterized by a horizontal growth pattern.
The anterior facial height is short, particularly the lower facial third ,
where as posterior facial height is long. Although the normal ratio
of upper to lower anterior facial height is 2:3 , it is reduced in the skeletal
overbite to a ratio of 2 : 2.5 to 2 : 2.8.
The inclination of the maxillary base is significant in the evaluation of the
treatment plan for this type of problem. An extreme horizontal growth
pattern can be at least partially compensated by an up and forward
inclination of the maxillary (ante inclination). On other hand , the
combination of horizontal pattern with a down and forward inclination
(retroclination) of maxillary base results in a more severe skeletal deep
overbite.
5

It is multi factorial. Skeletal type of overbite may be either due to
malrelationships of alveolar bones and/or underlying mandibular or
maxillary bones or to an overgrowth or undergrowth of one or more
alveolar segments.
Hereditary and may follow a genetic pattern or familial Condition
(autosomal dominant).
The class II division 2 pattern is known to have a strong familial
occurrence. Peck and Peck called it , heritable pattern of small teeth in well
developed jaws. According to their findings, the pattern of strong vertical
posterior development of mandible with upward and forward rotation and
Etiology
6

7
Skeletofacial hypodivergence anterioposteriorly, smaller mesiodistal
tooth diameters for the maxillary and mandibular incisors are characteristic
pattern of heritable skeletal and tooth size features in class II division 2
overbite malocclusion. These findings indicate the strong genetic influence
in the formation of angle class II division 2 deep bite discrepancy.
Ruf and Pancherz have reported a pair of monozygotic twins showing
malocclusion discordance with a class II division 1 malocclusion in
one(MSX 1) and division 2 another(MSX 2) . Based on this report , they
have hypothesized that hereditary is not the sole etiological factor of class
II division 2 malocclusion, as normally one would expect similar occlusion
in monozygotic twins.

8
Studies in twins with class II div 2 showed that monozygotic twins
displayed high concordance within malocclusion features, while
dizygotic twins showed 90% discordance in these features (Mossey,
1999).

A Detailed clinical examination of the dentition, occlusion, jaw
movements and soft tissue pattern of face is very important. For an
adolescent patient, a lateral Cephalograms must be taken to study the
skeletal, dental and soft tissue relationship and the growth pattern and
its status.
CLINICAL AND DIAGNOSTIC FEATURES
9

1. CLINICAL FEATURES
A) Extra Oral features
1. Patient has a short, square face and an edentulous appearance.
2. When the jaws are at rest, or when the patient is speaking or
Smiling, the maxillary incisors are hidden behind the upper lip.
3. The upper lip curves downward and the corners of mouth are
below the occlusal line.
4. When the mandible is in centric occlusion, distinct skin folds are
seen lateral to the oral commissure.
10

5. Upper third of face is within normal limits.
6. A study of the middle third of the face shows broad nasal alar bases and
large nostrils.
7. The posterior part of face appears wide because of prominent
mandibular angles.
8. The lips are thin and with an excess of lip height relative to face height.
This gives a curled appearance of the lips.
11

9.. The Naso -labial angle is essentially normal or obtuse.
10. With the mandible in a rest position and the upper lip relaxed, the
incisal edges of the maxillary anterior teeth are positioned above the
inferior margin of upper lip.
11. There is distinct chin button, which is made more apparent by a
deep mento labial fold and hyper active lowerlip.
12

12. Upper tooth to upper lip relationship is a vertical measurement
made in midline from the incisal edges of maxillary central incisor
to the most inferior portion of the upper lip. Usually this distance is
2-5 mm. If the upper teeth are buried under the upper lip, it indicates
skeletal deep bite.
13. Inter labial distance is the vertical distance between the most inferior
portion of the upper and lower lip when the lips are relaxed and the
teeth are in centric relation. In normal individual it is approximately
2mm. Decreased inter labial distance or redundancy of the lips
indicates skeletal deep bite.
13

B) Intraoral features
1. The maxillary arch is broad and the palatal vault is typically flat.
2. Majority of the problems in this category are created by premature
loss of permanent teeth causing a lingual collapse of maxillary or
mandibular anterior teeth. Similarly loss and / or mesial tipping of the
posterior teeth may also cause a deepening of the overbite, primarily
due to a decrease in the vertical height of the face.
3. In class II division 2 , maxillary central incisors are retroclined and
labial inclination of laterals, have short root , longer crown, axial
bending of incisors , reduced labiopalatal thickness, 12 ˚ more vertically
placed , decreased collum angle between crown and root and class II
molar and canine relationship.
4. Large inter occlusal space.
5. In the mandibular dentition it may manifest as a deep curve of spee or
reverse curve of spee in the maxillary dentition.
14

2. Cephalometric findings
1. Decreased Go–Gn angle.
2. Decreased occlusal plane angle.
3. Decreased Y – Axis.
4. Decreased FMAAngle.
5. Decreased Articular angle, Saddle angle & Gonial angle.
6. Increased Ramus height and Body length.
7.Decreased sum of posterior angles.
8.Decreased lower anterior facial height.
9.Increased jarabacks ratio.
10. Convergent upper and lower jaw bases.
11. Horizontal growth pattern or forward rotation
or anticlock wise rotation of the of the lower jaw
12. According to sassouni …..
15

I) POSITIONAL DEVIATIONS
1. The four planes of the face (Supraorbitale,(tangent to sella and parellel
with anterior cranial base) palatal, occlusal and mandibular plane) are
horizontal and nearly parallel to each other.
2. The midface is usually retrusive, creating a concave profile.
3. The posterior vertical chain of muscles (Masseter, Internal Pterygoid,
Temporal) are strong and attached anteriorly on the mandible and
stretches in nearly straight line vertically. The molars are directly under
the impact of masticatory forces on the posterior vertical chain of
muscles, results in greater depressive action is transmitted to the
dentition.
16

II) DIMENSIONAL DEVIATIONS
1. The Total posterior Facial height (Sella to Gonion) is nearly equal to
Anterior Facial Height .
2. The lower face height (ANS-Me) is equal or smaller than upper face
height (SOr - ANS).
3. A lack of ante gonial notch in the mandible leads to what is some times
called as a ‘rocking lower border of the mandible.
17

4. The facial breadth tends to equal to total face height, giving a square
face appearance in the frontal view.
5. The mandibular symphysis is short vertically and broad antero –
posteriorly.
6. The distance between supra mentale (point B) and pogonion is large,
creating a ‘chin button’.
7. Skull is usually round or brachycephalic and europrosopic face.
8. Nasion is deep-seated posterior to both frontal and nasal bones.
18

Forward Rotator Backward Rotator
1. Inclination
of
condylar head
Curves forward and back. Straight and slopes up
2.Curvature of
mandibular canal
Curved straight
Bjorks Seven Structural Guidelines 19

3.Shape of mandibular
lower border
Curved downward Notched
4.Inclination of
symphysis
(anterior aspect just below
B point)
Slopes backward Slopes forward
20

5.Interincisal
angle
Vertical or obtuse Acute
6.Interpremolar or
intermolar angle
Vertical or obtuse Acute
21

7.Anterior lower
facial height
Short Tall
22

Management of low angle case
23

Treatment modalities include
1)Intrusion of upper and lower anterior teeth.
2) Extrusion of posterior teeth.
3)combination of intrusion of anteriors and extrusion of posteriors.
4) Proclination of incisors.
5) Adult surgery.
24

Soft tissue considerations
a) Interlabial gap 2 to 3 mm is normal. If interlabial gap is excessive, molar
extrusion should be avoided.
b) Smile line In case of gummy smile , intrusion of maxillary incisors
should be done.
c)Lip length In cases of short upper lip, intrusion should be carried out.
25

Inter occlusal space The average inter occlusal space is 2-4mm in
premolar region.
Increase interocclusal space is an indication that
molars are not fully erupted. so treated by extrusion
of posterior teeth.
The presence of normal inter occlusal space is
indication of intrusion of anterior teeth rather than
extrusion of molars.
Reduction of normal inter occlusal space by
extrusion of molars can results in fatigue of
muscles of mastication which get stretched and
predisposed to relapse.
26

Dental considerations. Incisor intrusion is ideal to treat deep bite in
cases of supraeruption and gummy smile. It
maintains the vertical dimension. Upto 4 mm
of incisor intrusion can be achieved.
Skeletal considerations In case of decreased lower anterior face height ,
extrusion of molars is acceptable but it should be
attempted only in growing children. If the same is
attempted in adults, the stability of the result will be
questionable. In patients with increased face height,
intrusion of anteriors should be considered
27

Type of growth
pattern
Growing patient Non growing patient
Average grower Molar extrusion/incisor
intrusion
True incisor intrusion
Horizontal grower Molar extrusion Mandibular
advancement and Molar
extrusion
Vertical grower True incisor intrusion True incisor intrusion
28

Anterior bite plane
It is suggested by “callway and thompson”, who advocated stimulating
the eruption of the posterior teeth as a way of filling in the bite i.e ,
opening the bite anteriorly with a bite plate , then allowing the posterior
teeth to erupt into occlusion , through the reduction of excessive
freeway space.
A bite plate also used as an adjunct to fixed appliance treatment
especially in situation in which the patient otherwise would have heavy
contact on brackets bonded to the mandibular teeth.
29Removable appliances

With this appliance in the mouth during the mandibular closing
movement, the mandibular incisors come in contact with the acrylic
platform, which causes a disocclusion of the posterior teeth. The
disocclusion leaves the molars free to erupt.The disocclusion of
the bite accelerates the passive eruption of the posterior teeth,
which stops when one or more opposing teeth come in contact.
It is advisable not to disocclude the posterior teeth more than 2 mm.
If bite opening in the anterior region is not sufficient, the acrylic platform
can be augmented in small increments several times during the treatment.
30

In recent years either “ Bite Turbos ” bonded to the lingual surfaces of the
maxillary anterior teeth or buildups of bonding material on occlusal
surfaces of the molars or premolars bilaterally have been used to clear the
occlusion.
It should be remembered that increasing the vertical dimension during
class ΙΙ treatment , however , will tend to mask positive anterioposterior
changes in mandibular growth.
As a general rule each mm of increase in lower anterior facial height will
camouflage or mask a millimeter of increase in mandibular length by
autorotation the chin downward and backward.
31

The patient wears this appliance almost 24 hours a day. The use of bite
plates, at the time of attaining the desired overbite, should not be
Suddenly stopped, the bite plate itself should be used as a retainer and
its discontinuance should be gradual.
32

33
1) Myofunctional Appliance
Activator
Bionator
Twin block
Frankel II appliance
2) Extraoral Orthopaedic appliances
Cervical headgear
3) Fixed Functional Appliances
Herbst appliance
Jasper jumper
Forsus Fatigue resistance device
Twin force bite corrector
Growth Modulation Methods

34
TIMING OF TREATMENT
It is not logical to favour early treatment at age 8 – 10 years only for growth
reasons because there is plenty of mandibular growth still available at age
11- 13 years. Growth studies give only average values for the amount,
direction and timing of growth but there is wide variation among
individuals. It is recommended to start treatment in the late Mixed dentition
at dental age 11-12 years with entire correction being accomplished in one
treatment.
Class II molar relation tendency is easier to intercept prior to maxillary
second molar eruption. Early correction of skeletal deficiency , with an
orthopedic appliance , greatly reduce the time required for second stage
treatment.
Von Bremen and Pancherz investigated the efficiency of early versus late
Class II div I treatment in a group of 204 patients. They concluded that the
treatment of Class II div1 malocclusion is more efficient in permanent
dentition than it is in the mixed dentition.

35
Bondevik reported greater treatment success with increasing age of
the patient. The mean age in the group with satisfactory treatment result
was 11.95 years, while the mean age in the unsatisfactory group was 10. 87
years. This suggests that the treatment results were better with late treated
cases.
In 2004, Tulloch and co-workers published the outcomes from an important
10 year study on 137 patients in a prospective randomized controlled
trial. Their findings suggested that early and late treatment started before
adolescence in the mixed dentition might be no more clinically effective than
the treatment started during adolescence in the early permanent dentition.
They also noted that early treatment appeared to be less efficient because it
produced no reduction in the average time with fixed appliance.

36
In 2005, Hsich and coworkers investigated 512 consecutive patients and
found that it was inefficient to start treatment in the mixed dentition with
Early treatment objectives or to start treatment before the age of 10 years
in males and 10. 5 years in females.
The disadvantages of early treatment included prolonged treatment time,
increased patient/parent burn out and a worse incidence of compromised
treatment outcomes. In spite of these disadvantages, in few individuals an
early start of treatment can Be considered such as social or psychological
reason or risk of enamel damage.

Activator
Dentoalveolar deep overbite : When the deep overbite is due to
infra occlusion of the posterior teeth, the interocclusal clearance
is large and hence the construction bite is made high or moderate
depending on the size of the freeway space.
When the deep overbite is due to supraocclusion of the incisors,
the interocclusal distance is small, high construction bite should
not be used. Intrusion of the incisors is possible to only a limited
extent when an is being used.
37

In a skeletal deep overbite : The construction bite should be such that it is
5-6mm,more than the freeway space. Intrusion is achieved by loading the
incisal edges of these teeth. If they are ground properly they become the
only loaded or contacting surfaces, with no other than contact between
incisors and acrylic, even in alveolar area. If simultaneous use of active
labial bow is indicated , the contact between the bow wire and incisors is on
the incisal third.
Extrusion of molars can be facilitated by loading the lingual surfaces of
these teeth above the area of greatest convexity in the maxilla or below this
area in mandible.
38

Bionator
The Main objective is to establish a muscular equilibrium between the
forces of the tongue and outer neuromuscular envelope.
Balter’s terminology refers to stimulation of eruption as unloading or
promotion of growth and prevention of eruption as loading or inhibition of
growth.
Most bionators that are used in today are designed not only to posture the
mandible into more forward position but also to facilitate the eruption of
the posterior teeth in patients with decreased vertical dimension , so called
california bionator.
39

Trimming of acrylic tooth beds and elimination of the influence of tongue
and cheeks allow teeth to erupt until they reach the articular plane.
The difficulty in managing the classic bionator is the alternative loading
and unloading of certain areas. On one visit acrylic is added to load a
specific tooth. On the next visit it may be ground away in the same area.
Especially in the deepbite adequate space is necessary to allow for full
eruption of the teeth.
40

To allow extrusion of the posterior teeth , some acrylic is always left
interdentally at the level of occlusal plane, forming so called tooth bed.
The upper and lower molar regions should be trimmed first. Then lower
premolars are trimmed while the molars are loaded. Finally upper
premolars are stimulated while lower premolars and molars are loaded.
Care must be taken to ensure that lingual acrylic surfaces do not interfere
with eruption.
41

Control of incisors
The bionator is constructed typically so that the mandibular incisors
are covered with an acrylic incisal cap. The covering the lower
incisors presumbly prevents the vertical eruption of these teeth and
stabilizes the bionator in the mouth. The thickness of the acrylic cap
can be reduced for increased patient acceptance.
The maxillary incisors are restricted anterioposteriorly by the upper
labial and lingual wires. The incisal edges of the maxillary incisors
usually contact the top of the lower incisal cap , preventing vertical
eruption of incisors.
42

Frankel 2 regulator
Frankel 2 is indicated in the mixed dentition with short lower anterior
facial height ,deep overbite and abnormal activity, leading to bite opening
and facial esthetics.
Frankel appliance has buccal sheilds and lip pads that the prevent the
deforming muscle action in the dento alveolar region both during
deglutation and at rest.
Upper lingual wire originates from the buccal sheilds and runs between the
maxillary canine and the first premolar.
43

Lower lingual portion prevents the maxillary incisors from tipping
lingually after they were protruded by fixed or removable appliances.
Lingual wire is most important in cases with a deficient anterior lower
facial height particularly when forward rotational pattern.
The lingual shield lies lingually below the gingival margin of the
mandibular teeth and extends distally to the roots of the lower second
premolar. Its position is secured by two wires connecting it with the
buccal shields of either side.
Lingual shied is an important part of the exercise device which is used to
overcome the poor postural performance of the muscles suspending the
mandible.
44

The bite opening accomplished by when the upper and lower lingual
wires are bent against the cinguli of maxillary and mandibular incisors.
Thus an overeruption of the incisors can be prevented and the posterior
teeth are allowed to erupt spontaneously. Levelling the curve of spee is
mainly due to the buccal shields which prevent the adjacent soft tissues
of the cheek from lodging interocclusally.
45

It is act as a exercise device whenever the mandible tends to slide back to
its original position a pressure sentation on the lingual aspect the alveolar
process is provoked. This sensory input may activate the propioreceptors
in the gingiva and underlying periosteum and as a result of feedback ,
stimulate the protractors to eliminate this disturbing signal. however this
mode of action can be expected to be established if an anterior
displacement of the mandible carried out step by step.
46

Twin block
Aim is increase the vertical dimension and improve profile by increasing the
lower facial height by correcting the incisors to edge to edge relation while
adjusting the height of upper bite block in the molar region to encourage
molar eruption.
Deep bite reduced by overcorrecting to an edge to edge incisor relationship
with an interincisal clearance of 2mm in protrusive bite.
In recording the construction bite the clinician normally leaves 5mm of
clearance in first premolar region which is equivalent to 2mm of clearance
distally in the molar region.
Then trim the upper twin block Occulsodistally to encourage the eruption of
lower molars. The inclined plane is maintain intact through out treatment to
preserve the active mechanism for functional correction..the occlusion is
cleared over the lower molars by 1 to 2mm only.
47

At the end of the active phase incisors and molars are in correct occlusion
while open bite present in premolar region. The final adjustment is to trim
the lower block slightly to reduce the open bite in premolar region.
Eruption of lower molars occurs more quickly if separating elastics are
placed in inter dental contacts with adjacent teeth at the start of the
treatment or apply vertical elastics from upper appliance to hook on the
lower molars.
48

2.Extraoral Orthopaedic Appliance.
Cervical Headgear
The cervical (low- pull or kloehn) headgear is used most frequently in
patients with decreased lower anterior facial height.
The inner bow anchored to tubes that are placed on the buccal surfaces of
bands that are attached to the upper first molars.
49

The outer bow is connected to strap that extends to the cervical regions
and is anchored against the dorsal aspect of the neck. Usually the outer
bow of the face bow lies above the plane of occlusion(15 to 20 degrees),
so that force is directed through the center of resistance to prevent distal
tipping of the molars during treatment.
Numerous clinical studies showed that the forward movement of the
maxilla inhibited through the use of this type of appliances. It is also
increase the vertical dimension through extrusion of molars.
50

Herbst appliance
The herbst appliance can be compared with a an artificial joint between
the maxilla and mandible. The bilateral telescopic mechanism maintains
the protracted position of the mandible even during function.
It consist of a tube , plunger , two pivots and two locking screws that
prevents the telescopic elements from slipping past pivots.
The pivot for the tube usually is soldered to the maxillary first molar
band and the pivot for the plunger is attached to the mandibular first
premolar band.
51Fixed Functional Appliances

In class 2 malocclusions with deep bite may be reduced significantly
with herbst therapy , this results are mainly from eruption of lower
molars and intrusion of lower incisors.
One of the major advantage of the herbst appliance is the relative
speed at which treatment effects are achieved .
The disadvantage is rigidity of the bite jumping mechanism ,
although every attempt is made to allow freedom of movement by
having the orthodontist enlarge the attachment holes of the tube and
plunger to the axles(complex laboratory work ),the bite jumping
mechanism can restrict lateral movement of the mandible.
52

Jasper jumper
Jasper jumper modular system can be used with most types of fixed
appliances.
The system is composed of force module and anchor units.
The force module , analogue to the tube and plunger parts of the herbst bite
jumping mechanism, is flexible . The force module is constructed of a
stainless steel coil or spring that is attached to the both ends to stainless
steel Endcaps, in which holes have been drilled in the flanges to accomdate
the anchoring unit. This module is surrounded by an opaque polyurethane
covering for hygiene and comfort.
The module are available in seven lengths , ranging from 26mm to 38 mm
in 2mm increments. They are designed for use on either side of the dental
arch.
53

The force module is attached posteriorly to maxillary arch by a ball pin
that is placed through the face bow tube on the maxillary first molar band.
The ball pin is anchored in position by having the clinician place a return
bend in the ball pin at its mesial end.
Anteriorly the module is anchored to the mandibular arch wire. Bayonet
bends are placed distal to the mandibular canines and small lexan beads
are slipped over the arch wire to provide an anterior stop.
54

When the force module is straight , it remains passive. As the teeth
come into occlusion , the spring of the force module is curved axially as
the muscles of mastication elevate the mandible, producing forces from
one ounces to sixteen ounces. This kinetic energy then is captured when
the force module is curved , and the force is converted to potential
energy to be used for a variety of clinical effects.
55

Forsus fatigue resistance device
The Forsus Fatigue Resistant Device (FRD) is an alternative interarch
appliance for treating Class II malocclusion. A mandibular push rod
attaches directly to the lower arch wire distal to the canines, and a
telescoping spring attaches to the headgear tube with an L-pin or EZ
module. Forces are unloaded when the patient’s jaw opens, resulting in
intrusive rather than extrusive force vectors.
The Forsus FRD exerts a continuous force with more elasticity and
flexibility than the Herbst, permitting a greater range of mandibular
opening and lateral movements during speech, chewing, and
swallowing. Because muscular forces are distributed over a larger
periodontal area, there is less inhibition of the jaw elevator muscles by
the periodontal mechanoreceptors, allowing better stabilization of the
mandible.
56

Modified the .019" × .025" stainless steel mandibular arch wire by
incorporating a small, circular occlusal loop on each side, distal to the
canines. The mesial end of the mandibular push rod is placed over the
arch wire just distal to this occlusal loop and crimped slightly to secure
it . The point of force application is thus shifted from the canine
brackets to the rigid mandibular arch wire, distributing the forces over a
wider surface area.
In cases where the inter bracket span is too narrow to permit placement
of the mandibular push rod distal to the occlusal loop, the mesial end of
the push rod can be inserted directly into the loop and crimped in place.
57

Twin force bite corrector
The TFBC is a fixed, push-type intermaxillary functional appliance
with ball-and-socket joint fasteners that allow a wide range of motion
and lateral jaw movement .The two plunger/tube telescopic assemblies
on each side contain nickel titanium coil springs that deliver a constant
force. Measuring several appliances with a force gauge demonstrated
an average full-compression force of approximately 210g.
58

Titanium components provide a secure lock onto the arch wire, allowing
every placement and removal of this single-piece appliance to be done
chair side in just seconds Time and cost savings , No waiting for the
lab to fabricate the appliance No patient cooperation required .
Maximum results with minimal patient cooperation, Comfortable .
Increased lateral excursion not found with most distal zing appliances
Versatile, Suitable for both extraction and non-extraction cases .
The appliance is attached to the maxillary and mandibular arch wires by
hex nuts fastened mesial to the maxillary first molars and distal to the
mandibular canines. At full compression, the TFBC postures the patient's
mandible forward into an edge-to-edge occlusion.
59

Magnetic Activator Device (MAD), was introduced by Darendeliler and
Joho.
The design of the MAD II developed progressively using smaller
magnets(samarium-cobalt and neodymium-iron-boron) and reduced force
levels. The magnet shape and dimensions changed from a rectangular bar,
to a triangular prism and then to a cylindrical form.
Darendeliler and Joho commented that the skeletal versus dental response
depended on the intensity of the magnetic force. The use of attracting
magnetic forces, ranging from 150 to 600 grams per side, revealed that a
force of more than 500 grams appeared to produce unwanted or
exaggerated dental movements.
Magnets-MAD II Appliance
60

Forces below 200 grams were insufficient to obtain protrusion of the
mandible. A force of 300 grams per side was found to be appropriate in
patients age 7 to 12 for correcting Class II malocclusion by growth
modification with only minimal tooth movement.
The MAD can be worn full time, except during meals since phonation and
deglutination are not as limited. It has also been suggested by Darendeliler
that bonded magnetic appliances could be used as fixed functional
appliances.
The advantages of magnets over traditional force delivery systems are:
frictionless mechanics, predictable force levels and force direction when
the magnets are in attractive configuration, no force decay over time, and
less patient cooperation.
61

62
i) Segmental arch mechanics
Burstone intrusion arch
Three piece intrusion arch
Rickets utility arch
ii) Continuous arch mechanics
Anchorage bends
Bite opening curves
Connecticut Intrusion arch
iii) Loop Mechanics
K - sir arch
Asymmetric T- loop
iv) Extrusion of posterior teeth mechanisms
Tip back mechanism
Base arch mechanism
0.016 distal extension
parallel eruption of buccal segment
Fixed Mechanotherapy

63
Fixed orthodontic appliances can be used to intrude the incisors or
extrude the molars. They can also produce mild skeletal effects
(increases the lower anterior facial height). Appliances used for
deep bite correction are generically termed intrusion arches and
variations include base arches, utility arches, Connecticut arch and
Reverse curve of Spee wires etc..,.
Incisor overbite correction can be accomplished by two methods.
One method is by the extrusion of posterior teeth, which increases the
lower face height by mandibular rotation.
The second method is by the intrusion of the upper or lower incisor teeth,
with little or no mandibular rotation.

Treatment modalities in growing and non growing patients.
1. Growing patients.
Intrude anteriors.
Erupt posteriors.
Combination of posterior eruption and anterior intrusion.
2. Non growing patients (little or no growth expected)
Orthognathic surgery
Intrusion of anteriors (posterior extrusion invariably relapses)
Whatever the treatment modality the management of deep bite is by
intrusion of anteriors, extrusion of posteriors or combination of the both
64

Intrusion of anteriors
Intrusive mechanics is considered in the following situations .
Deep bite with large inter labial gap(In a relaxed mandibular position, an
individual has normal of 2 to 4 mm) , intrusion is the ideal choice.
Extrusion of posteriors may deteriorate the esthetics and further
increase the inter labial gap.
In a clinical situation, if incisor-stomion distance is large, ( the distance
between the incisal edge of the maxillary central incisor to the lower most
border of the upper lip is an average of 2 to 4 mm) which is often
associated with a high smile line or "gummy smile", the best method of
treating a deep Overbite may be by intrusion of the upper incisors.
65

In a Class II, division 1 type of malocclusion with large vertical facial
height, extrusion of posterior teeth may cause serious functional, esthetic,
And stability problems. Extrusion of molar furthers causes the downward
and backward rotation of the mandible worsening the condition. In those
Cases the intrusion of anteriors is the treatment option.
Intrusion mechanics are considered if there is inadequate or normal
freeway space. Encroachment of this space by extrusion of posterior teeth
is determinant and bound to relapse. It results in fatigue of the muscles of
Mastication which get stretched and predispose to relapse. It also strains
the TMJ.
66

Teeth Force value(grams)
Maxillary central incisor 12-15
Maxillary lateral incisor 8-10
Maxillary canine 25
Mandibular central incisor 8-10
Mandibular lateral incisor 8-10
Mandibular canine 25
Maxillary four incisors 35-50
Mandibular four incisors 30-40
FORCE VALUES FOR INTRUSION OF ANTERIOR TEETH
67

Absolute intrusion .
Relative intrusion - Achieved by preventing
eruption of incisors while growth provides
vertical space into which posteriors erupt.
Extrusion of posterior teeth causes the
mandible to rotate downward and back
in the absence of growth.
68

Levelling by Intrusion .
This requires a mechanical arrangement other than a continuous arch wire
attached to each tooth (Proffit, 2000). The key to successful intrusion is
light continuous force directed towards the apex. It is necessary to avoid
pitting intrusion of one tooth against extrusion of its neighbour, since in
that circumstance, extrusion will dominate. This can be accomplished in
two ways:
1) with continuous arch wires that bypass the premolar (and frequently the
canine teeth)
2) with segmented base arch wires (so that there is no connection along the
arch between the anterior and posterior segments) and an auxiliary
depressing arch.
69

Continuous Arch Mechanics Segmental Arch Mechanics
Reverse curve of spee in lower
Exaggerated Curve in Upper
Intrusion Arches
Extrusion of Premolars and molars Intrusion of Incisors only
Increase lower anterior facial Height
by rotating the mandible open.
Mandible may rotate closed or be
prevented from rotating open.
Flare Incisors Labially.
Intrusive force against the incisors is
applied anterior to the centre of
resistance causes incisors to tip
forwards as they intrude .
No Flaring of Incisors.
The point of force application may be
altered by tying it more distally. The
force is then closer to the labial
segment’s centre of resistance – this
prevents incisor proclination without
straining posterior anchorage
70

Extrusion of posterior teeth.
In deep bite with redundant upper and / or lower lips , or no
Inter labial gap, posterior extrusive mechanics may be desirable (if
other considerations permit).
If a patient with deep overbite exhibits normal incision - stomion
distance, the choice of correction of deep bite by an intrusion of
maxillary incisors is often contraindicated since it will give the
Patient an edentulous appearance. Extrusion of posteriors is the
treatment option .
In patients having excessive overbite with Class II, division 2 type
of skeletal malocclusion, an extrusion of the posterior teeth met be
the treatment of choice ( if other considerations permit). Extrusion
mechanics are considered if there is adequate inter occlusal space.
72

73
correction of deepbite by this method is often indicated in patients having
steep occlusal plane angle . The buccal segments are negatively rotated as
they are erupted, because the movement of force is coming from cantilever
type appliances. These are generally used in the lower jaw to level the deep
curve of spee by eruption of the posterior teeth.
Deep overbite correction by erupting the posterior teeth occurs fairly rapidly,
the eruption of posterior teeth so much faster than intrusion of teeth .The
choice of which eruptive mechanism to use depends upon the choice of
center of rotation. The posterior teeth usually be leveled about several center
of rotation , depends on the amount of required arch length.
The four types of extrusion mechanisms are
1.Tip back mechanism.
2.Base arch mechanism.
3. 0.016 inch distal extension.
4. Parallel eruption of buccal segment.

An increase in proclination of upper and lower anterior incisors can
effectively decrease the deep bite. Flaring incisors tends to decrease
overbite secondary to the rotational movement of the incisor crowns.
For mild to moderate corrections , this approach may be very effective.
It is best indicated in lingually tipped incisors , such as class 2 div 2
malocclusions or class 3 malocclusion then can withstand flaring of the
upper and lower incisors.
74
Proclination of incisors Dr Ravikanth Lakkakula

A Intrusive arch normally consists of an 0.018 x 0.025 inch ss by with a
two and half turn helix or alternatively .019 x .025 TMA without helix,
2 mm mesial to the auxiliary tube. Curvature is placed in the intrusive
arch, so that the incisal portion lies gingival to the central incisor.
When the arch is tied to the level of the incisors, an intrusive force(10-
15grams) is developed. In order that the arch does not increase its length
during the activation, a gentle curvature should be placed with the
amount of curvature increasing as one approaches the helix.
In this way the activated arch wire will appear relatively straight, and as
it works out during intrusion, arch length will decrease and no anterior
flaring is produced.
Burstone intrusion arch
75

Three piece intrusion arch
It is introduced by burstone , shroff,lindauer and leiss in 1995
It consist of following parts :
1)The posterior anchorage unit
2) anterior segment with posterior extention
3) intrusion cantilevers
4) elastic chain.
The anterior segment(019x025 ss) was bent gingivally distal to the laterals , then
bent horizontally , creating a step of approximately 3mm.the distal part is
extended posteriorly to distal end of the canine bracket, ending in the form of a
hook. The anterior part was fabricated heavy stainless steel wire to prevent side
effects created by bending of wire during force application.
The posterior segments are consolidated using 019 x 025 ss wire from canine to
second molar.
76

The anterior segment allowed further displacement of the intrusive forces,
which was desirable in case of flared incisors.
The intrusion cantilevers are fabricated from 017 x 025 inch TMA wire.
The wire was first bend gingivally mesial to the molar tube then helix
formed. On the mesial end a hook was formed for placement of intrusive
forces on anterior teeth. It is activated by placing a bend mesial to the
molar tube then cinch back. A E - chain was attached to produce
simultaneous intrusion and retraction.
E chain was extended from molar hook to posterior hook of the anterior
segment. A 150 grams force per canine used with e chain for separate
canine retraction. A 200 grams force used for incisors retraction after
canine retration.
77

Fabricated from blue elgiloy either .016" x .016 " or .016 " x .022 “ for
018 slot and .019 " x .019 “ for .022 slot . Generally rectangular wires are
preferred than round wires to control torque and to prevent unwanted
tipping of incisors. Other types of arch wires also used(TMA).
It consist of molar segment extends into a tube or may be bent gingivally ,
if the utility arch is to be tied back.
Posterior vertical segment is formed by making a 90 degrees bend.This
posterior step is 3-4mm in mandible.
Ricketts utility arch
78

Vestibular segment is formed by placing a right angle bend at inferior
portion of the posterior vertical segment.
Anterior vertical segments(90 degree bend) should be about 4-5mm in
length when the utility arch is used in the mandible. Its depths is differs
from patient to patient.
In contrast to the passive utility arch that fits flush against the auxillary of
the molar tube , there is atleast a 5mm space between the anterior border
of the auxiliary tube and posterior vertical segment of the utility arch.
79

Intrusive force are produced by using loop forming pliers to place an
occlusally directed gable bend in posterior aspect of the vestibular
segment.
After activation, the vestibular segments and anterior and posterior
vertical segments, which serve as long lever arm from the molars to the
incisors , deliver a light continuous force. The utility arch produce 60-100
grams of force on the mandibular incisors , a force level considered ideal
for mandibular incisor intrusion.
80

Anchor bends are given in the .016 inch Australian stainless steel arch
wire 2mm mesial to the molar tube , so that the anterior part of the arch
wire lies gingival to the bracket slot . Thus when these arch wires are
pulled occlusally and engaged into the brackets, a gingivally directed
intrusive force is exerted on the incisors which reduces the deep bite.
When intrusion of anterior teeth is the goal, light forces should be used.
Heavier forces are more likely to create a greater tendency for posterior
teeth to erupt as a result of the equal and opposite extrusive force at the
molar.The reactionary extrusive force on molars is prevented by natural
Interdigitating occlusion or in extreme cases by giving a posterior bite
plane of minimum thickness.
Anchorage bends 81

Intermaxillary elastics
Extrusion of molars might be fortified by means of elastics, which
attempt to overerupt the molars in both the upper and lower jaws. Use of
anchorage bend in the upper jaw as well as in the lower jaw in
combination with Class II elastics may cause overeruption of the lower
molars and may help to correct a dental deep bite.One of the draw backs
of the class II elastics is that it results in extrusion of the upper incisors,
in an attempt to over erupt lower molars.
82

Bite opening curves
one millimeter of upper or lower molar extrusion effectively reduces the
incisor overlap by 1.5 – 2.5mm and 3 mm increases in lower anterior
facial height.
A very common method is use of reverse curve of spee in lower and
exaggerated curve of spee wires in upper arch and progressively increase
in step bends in arch wires.
83

Reverse curve of spee correct the deep bite primarly by extrusion of
posterior teeth , along with intrusion and flaring of incisors. Both
extrusion and flaring may be unstable movements due to their effect on
the facial neuromuscular balance. Reverse curve of spee wires also alter
their the axial inclination of posterior teeth, which may also contribute to
relapse.
84

Placement of step up (Maxillary incisors) and step down (Mandibular
incisors) bends also commonly used to correct deepbite. This method
of correction combines extrusion of the adjacent cuspids and posterior
teeth and perhaps some intrusion of incisors described by burstone
and koenig.
The step bends creates two movements in same direction causing
changes in the axial inclination of teeth and cant of the occlusal
planes.
85

Step bends are indicated when there is a step between the anterior and
posterior occlusal planes, in cases with moderate to minimal incisors
display, and class ǀ malocclusions. The primary drawback of this approach
is the resultant indiscriminate posterior extrusion versus anterior intrusion
and the change in cant of the occlusal plane towards a deep bite.
86

The CTA is fabricated from a nickel titanium alloy to provide the
advantages of shape memory, springback, and light, continuous force
distribution. It incorporates the characteristics of the utility arch as well
as those of the conventional intrusion arch.
The CTA is preformed with the appropriate bends necessary for easy
insertion and use. Two wire sizes are available: .016" x .022" and .017" x
.025". The maxillary and mandibular versions have anterior dimensions
of 34mm and 28mm, respectively.
Connecticut intrusion arch
87

The CTA's basic mechanism for force delivery is a V-bend calibrated to
deliver approximately 40-60g of force. Upon insertion, the V-bend lies
just anterior to the molar brackets. When the arch is activated, a simple
force system results , consisting of a vertical force in the anterior region
and a moment in the posterior region.
88

Simultaneous intrusion and retraction of the six anterior by using
non-frictional loop mechanics, which was developed by Dr. Varun
Kalra, based on space closure mechanics advocated by Dr. C. J.
Burstone.
A continuous 0.19" x 0.25" TMA archwire with closed7mm x 2mm
U-loops at extraction sites . 90˚ V-bend is placed in the archwire at
the level of each U-loop by placing centered V – bends which create
two equal and opposite moments.
K- SIR arch wire
89

A V-bend located posterior to the center of inter bracket distance to
augments molar anchorage during intrusion of anterior teeth. And 20 ˚
Anti-rotation bends are placed to prevent molar rotations. 0.019" x
0.025" TMA provides sufficient strength to resist distortion, but
enough stiffness to generate required moments. At the same time TMA
has low forces, low load deflection rate and high range of activation.
90

A system made of .019” x .025” TMA (.022” brackets) and .017” x .025”
TMA (.018”brackets) has been proven effective in achieving simultaneous
intrusion and retraction of incisors. This asymmetric “T” loop archwire has
a loop that is placed distal to the upper lateral incisors. The loop can be
activated intraorally for the multiple adjustments like, intrusion and
retraction of incisors, or to increase torque during retraction.
A small rounded bird beak plier is used to bend the loop into a preformed
TMA archwire. Shape memory of the wire and the loop configuration
make this a multipurpose system which can be incorporated into a
continuous archwire. The vertical portion of the loop should be 5mm, the
anterior loop 2mm, and the posterior loop 5mm. The archwire has an
exaggerated reverse Curve of Spee and strong distal molar rotation. Bend
the loop inwards to prevent irritation to the cheek.
Asymmetric T - Loop
91

92
Indications
1. In growing patients with a forward growth rotation.
2. For deep curve of spee in lower arch.
3. For a deep overbite.
4. For slight arch length inadequacy(1-2mm per side).
5. For a steepened natural plane of occlusion.
The tip back mechanism consist of
1. 0.036 inch lingual arch.
2. 0.018 x 0.025 inch anterior segment , which can sometimes be left long,
distal to the cuspids.
3. Buccal stabilizing segments of 0.018 x 0.025 inch from(ideally) 7- 4.
4. 0.018 x 0.025 tip back spring.
Tip back mechanism

93
The anterior portion of hook that can be placed over the anterior segment
of wire. As it is activated (hooked over the anterior segment) , it produces
a negative moment and an eruptive forces to the buccal segment
(producing a C Rot at the distal aspect of the root of the second molar).
In which , as the buccal segment becomes upright, some arch length
gained anteriorly. Such a C Rot is found at the distal most aspect of the
lower second molar, as the buccal segment is uprighted , one notices space
appearing between the first premolar and canine .

94
The hook of the tip back mechanism , made so that it can slide freely in
an anterioposterior direction , can be placed strategically over the 0.018
x 0.025 inch anterior segment.
For example the anterior segment has normal inclination , the hook
should be placed between the canine and lateral incisor (the approximate
location of C Res of the anterior segment).
If the lower anterior segment is slightly flared with the canines
somewhat higher than the incisors , the depressive force should be
placed distal to the C Res of the anterior segment.

95
With the correct use of tip back mechanism , one will notice that
1. The C Rot is placed distally , somewhere around the distal root of the
second molar.
2. There is eruption and rotation of the buccal segments.
3. There is increased arch length distal to the canines(1 to 2 mm).
4. The second molar is often buried.
5. With the hook is placed distal to the C Res of the anterior segment , the
roots of the lower anterior segment often come forward , which is good ,
if one is flattening the plane of occlusion.
6. There is no flaring of the anterior teeth, because the hook is made to slide
freely along the anterior segment.
The 3500 to 4500 gm of force is required to erupt and rotate the buccal
segments optimally.

96
The base arch mechanism (sometimes also called an intrusive arch) can
also used for extruding teeth in deepbite correction.
The main difference between Tip back mechanism (distal most aspect of
the lower second molar) and base arch (located close to the mesial root
of lower first molar) is in the location of the center of rotation.
Base arch mechanism
Tip back mechanism
Base Arch mechanism

97
The base arch mechanism is made from 0.018 x 0.025 inch ss wire with
helicles, can also be fabricated from 0.017 x 0.025 inch TMA wire with
no helicles or instead , a washer can be crimped on or a short piece of
wire can be welded on for stop. when flaring of anterior teeth is not
indicated , a ligature wire can be passed through the helicles to tie the
base arch back.
The force system is nearly identical to that of the tip back spring, expect
the fact that there is no anterior hook free to slide anterioposteriorly ;
with the base arch tied back securely.

98
With the correct use of base arch mechanism , one will notice that
1. Eruption and a negative rotation of the buccal segment (flattening
of the plane of occlusion)
2. No increase in arch length.
3. That the roots of the buccal segment move forward.
4. That second molars appear to be buried (remember the negative moment)
The force values used are based on the same optimal moment desired to
erupt and rotate the buccal segment , i. e., 3500 to 4000 grams.

99
Sometimes , in order to level a deep curve of spee, both anterior and
posterior segments need to be erupted and rotated. This eruption can be
done with an appliance called 0.016 inch distal extension.
In order to use this appliance, there should be
1. Good growth increments remaining, since the appliance is eruptive.
2. A significant second- order discrepancy between the canines and the
incisors; Incisors should be higher than the canine.
3. Minimal arch length required (2-3mm per side).
4. A deep curve of spee.
5. Extraction of teeth, usually the first premolars.
0.016 distal extension

100
The appliance itself consist of
1. 0.018 x 0.025 inch base arch wire with helicles , but it may be made
without them , especially if the newer , more flexible wires such TMA
are used.
2. 0.016 inch distal extension – immediately mesial to the canine bracket a
vertical loop is placed and immediately distal to the canine bracket a
helix is placed. The distal extension can be adjusted to lie over the tie
wings of the second premolar bracket , or can be hooked over the
buccal segment wire. It can be opened the amount of the inadequacy
that might be present(upto 2-3mm per side).

101
In order that this arch length inadequacy can be resolved by the canines
being nuged back distally rather than by the incisors moving anteriorly ,
the base arch is tied back anteriorly at the midline and posteriorly
through helicles.
3. 0.036 inch lingual arch.
When the base arch is activated , the buccal segment will experience a
negative moment tending to move its roots mesially and crowns distally.
There is a corresponding depressive action of incisors. This depressive
force is also mesial to the C Res of the anterior segment , so it produces
distal root movement.

102
If one consider the effects of both appliances (base arch and 0.016 distal
extension) , one can see that both alpha (anterior) and beta (posterior)
moments are produced when each respective arm is activated.
If both are given equal and opposite preactivated bends (alpha = beta )
both anterior and posterior segments will erupt and rotate (mesial root
movement on the buccal segment and distal root movement on anterior
segment).
Higher alpha movement results in more eruption and rotation of the
anterior segment; higher beta movements results in more eruption and
rotation of the buccal segment.

103
Parallel eruption of the buccal segments is used in the upper jaw only.
Using a cervical headgear with its long outer bow bent high (about 60
degrees), a negative moment is provided by bringing the outer bow down to
the line of action of the headgear straps. Once engaged , the line of action of
the force times the perpendicular distance away from the C Res of the upper
jaw produces a positive movement. Both moments tend to cancel each other
out and is left with a purely extrusive force to the buccal segments.
Parallel eruption of the buccal segment

Bilateral implants for en-masse intrusion of anteriors:
The implants used are 1.3 mm in diameter and 8 mm in length. Bone
contacts at insertion influences the primary stability of the implants.
Increasing the diameter and length of the implant allows greater surface
area contact between the bone and implant. It’s important to have a
mechanical inter digitation between implants and cortical bone.
Placement Site:
For enmasse intrusion of the maxillary anterior teeth the most suitable site
for the placement of implant selected is the alveolar bone between lateral
incisor and canine bilaterally at the level of attached gingiva.
Implants
104

Clinical set up
1.The maxillary dental anterior segment should extend from distal of
canines on either side. A .021x .025 stainless steel arch is placed in all
the three segments. In the anterior segment, hooks are placed
between lateral incisor and canine bilaterally. This is followed by
placement of mini implants which are loaded immediately.
2. A calibrated Dontrix gauge is used to measure the amount of intrusive
force being applied. 45 gms of intrusive force is applied per side using a
pre-stretched elastic chain i.e. a total of 90 gms of intrusive force is
applied to the six anterior teeth.
3. A ligature wire lace back is tied extending from the maxillary molar
hook to the tag incorporated distal to canine in the anterior segment.
105

Mid-implant for intrusion of maxillary incisors
The implants used are 1.3 mm in diameter and 8 mm in length. A
stainless steel archwire with utility design engaging four incisors and
two molar, bypassing the canine and premolar is used made of
0.017x0.025 .Passive segmented posterior stabilizing unit (0.019x0.025)
A closed coil spring or a E-chain can be used to deliver force of around 60-
70 grams.
106

The bite-plate effect of lingual brackets is well known Lingual brackets
which are bonded on the palatal surface of the maxillary incisors act like
a bonded anterior bite plate. This is relevant for all types of Lingual
brackets, but more significantly for the 7 th Generation brackets (G7)
which have a built-in bite plate in the anterior brackets.
The bite plate represents a combination of different treatment strategies;
it forces the mandible to open in backward rotation and allow the
posterior teeth to extrude passively or actively, while simultaneously
intruding the anterior teeth that are in contact with the plate.
The bite-plate effect therefore has a significant clinical contribution for the
treatment of deep bite cases, anterior or posterior X-bite and Class III
tendency.
Bite plate effect (lingual technique) 107

On the other hand there are some clinical situation in which the bite plate
effect may have an adverse effect on the malocclusion,
1. Moderate class II cases with increased over jet, The bite-plate effect of
the lingual brackets forces the mandible to open in backward rotation and as
a result the over jet increases, Class II molar and canine relation may be
aggravated. This point should be considered in the treatment plane and
anchorage considerations.
2. Another risky situation is severe incisors proclination, when the lower
incisors contact solely on the anterior brackets, tending to worsen the
proclination .
3.More severely it is for periodontal patients when the bone level is
reduced
4. The opposite extreme incisors inclination, when upper incisors are
severely retroclined, is also risky when using anterior bite plate, since there
is a tendency for the upper incisors to further retrocline due to occlusal
forces applied palatal to the center of resistance.
These adverse effects could be avoided by using temporarily posterior
bite blocks.
108

It is made of plastic , designed by factory, are lingually placed 1-2 mm
thick horizontal rectangular attachments, horizontal gingival beveled
attachments or vertical rectangular attachments.
Align’s default is the horizontal beveled attachment. Virtual Bite Ramps
are never bonded to the teeth but act as a bite ramp when the patient has
the aligners in place. By discluding the posterior teeth they prevent
transient posterior intrusion. The amount of overjet will determine how
thick you make the virtual bite ramps and whether you use horizontal or
vertical orientation.
Invisalign virtual bite ramps
109

If the patient has a large over jet, their lower incisors will not contact
the Virtual Bite Ramps and you will not see the same bite opening effect.
Mandibular advancement, class II elastics and upper Incisor position can all
reduce over jet to allow contact with the virtual bite ramps. Vertically
oriented bite ramps will follow the lingual slope of the upper incisors and
will allow earlier contact with the bite ramps in those patients with large
over jets.
If we want to add this in the middle of the treatment by adding bite ramps
to an aligner with Orthoarch mini mold anterior bite ramp with the
Bite Plane Plier invented by Dr. Keith Hilliard.
110

In adult patient showing excessive deep overbite of 100 per cent or more,
with accompanying;
1. High smile line.
2. Decreased Vertical facial height.
3 . Alveolar problems, the length of treatment may be very long.
In this instance, the patient should be given a choice for a Orthognathic
correction of the problem. In these patients, the treatment plan to
correct the excessive overbite should be done in conjunction with an
Oromaxillofacial surgeon.
Surgical management
111

Maxillary surgery :
The maxilla can be moved up quite successfully with Lefort I. Surgically
repositioning of maxilla in superior direction can be done by complete
maxillary osteotomy. The correction of deep bites resulting from vertical
maxillary excess can be effectively corrected by this method.
112

Mandibular surgery :
Patients with a short face (skeletal deep bite) problem are characterized
by along Mandibular Ramus, square Gonial angle and short nose-chin
distance. They are treated most predictably and successfully by
mandibular Ramus surgery that allows the mandible to move downward
only at the chin, increasing the mandibular plane angle. They are
treated best by Saggital Split mandibular Ramus surgery to rotate the
mandible slightly forward and down and the Gonial angle open up.
The deep bites in the anterior mandibular alveolar region corrected by
Sub Apical Osteotomy.
113

114
Reduction of interincisal angle and establishment of guidance between the
maxillary and mandibular incisors is important for the stability to be
achieved in overbite correction. Muscular forces and growth , both have
play in successful treatment of the class II division 2 malocclusion. In adult
patients , vertical development of the buccal segments can not be expected
and the stability of the bite opening is questionable.
Hypodivergent facial types like class II division 2 with a deficiency in lower
anterior facial height usually present problems in maintenance of permanent
overbite correction. It has been reported that deep bite cases in which lower
facial height is increased during treatment , exhibited less relapse than in
cases in which little or no increase occurred during treatment. However, in
patients where overbite correction was accomplished during their respective
growth periods and those in whom vertical growth continued after retention
seemed to maintain this correction many years out of retention.
Stabilty and Retention

Low angle case is a common form of malocclusion, that maybe
addressed in many ways , including posterior extrusion , anterior
intrusion and incisor flaring. The specific approach to bite opening
should be selected based on each patients needs. Soft tissue, crown-
gingival relations , occlusal plane and skeletofacial concerns are among
the special considerations for treatment planning for low angle case
corrections. Selecting the method and mechanism of the bite opening
based on these considerations affords the opportunity to deliver goal
oriented treatment. Understanding the biomechanics of the appliances
chosen improves the clinicians ability to achieve the desired results.
Conclusion
115

Management of low angle case in orthodontics

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