Prepared by:
Ashraf Qussous
3rd year resident

Bjork 7 Structural Guideline

overbite depth indicator (ODI)
 Is the angle the A-B plane makes with the mandibular
plane combined with the angle of the palatal plane to
the Frankfort horizontal.
 PP-FH is positive it is added this value from AB-MP
and vice versa.
 A value of less than 68º is said to indicate an open bite
tendency

Features of anterior open bite
angle and/or long face syndrome
 Skeletal feature
 Tapered facial type.
 Long lower third of the face,
 Long maxilla
 Short mandible
 Short ramus
 Class II skeletal relationship
 Intraoral features
 Open bite
 Class 2 tendency
 Increased overjet
 Narrow upper arch
 Crowded LLS
 Growth feature
 Usually posterior growth rotation

Features of anterior open bite
angle and/or long face syndrome
 Cephalometric feature
 Enlarged adenoid seeing in the ceph.
 Increased dentoalveolar height in molar region and
reduced dentoalveolar height in incisor region due to weak
muscle allowing molar eruption. (Neilsen, 1991)
 Bjork’s seven features of posterior growth rotation.
 Jarabak ratio: 58 high angle case, reduced OB.
 UAFH-LAFH ratio: less than 65%.
 The overbite depth indicator (ODI) less than 68 degree.

Cephalometric feature
SN/MP angle 40º or greater
OP/MP angle 22º or greater
MxP/MnP angle 32º or greater
AOB negative overbite
PFH/AFH (Jarabak ratio) 58% or less
UFH/LFH 0.65 or less
Overbite depth indicator (ODI) 68

Features of anterior open bite
angle and/or long face syndrome
 Soft tissue features
 Long lower third of the face.
 Narrow nose.
 Narrow alar bases.
 Decreased naso-labial angle.
 Incompetent lip.
 Excessive exposure of maxillary anterior teeth and gingiva at rest
and smiling which is due to dentoalveolar compensation of the
anterior part of the maxilla to compensate for AOB.
 Retruded chin.

Features of anterior open bite
angle and/or long face syndrome
 Intraoral features
 Anterior Open bite.
 Class 2 tendency.
 Increased overjet.
 Narrow upper arch.
 Crowded LLS.
 Growth feature
 Usually posterior growth rotation.

Etiology
Skeletal factors
Genetic Environmental
Juvenile
rheumatoid
arthritis
Trauma to TMJ Hormonal
Soft Tissue
factor
Muscle of
mastication
Neurological
disturbances
Chronic nasal
obstruction
Adenoids
Habit
Digit Sucking
Habits.
Endogenous
(primary) thrust
Eg. Downs-
Syndrome

Treatment
 Stop the habit.
 Myofunctional Therapy.
 Myofunctional+EOA combination Therapy.
 Extraoral Traction.
 Fixed Appliances.
 Molar intrusion using skeletal anchorage.
 Repelling magnets.
 Orthognathic Surgery.

Treatment of digit-sucking habits,
BOS guidelines 2000
 The child must want to stop.
 A child who is undergoing severe psychological trauma
is unlikely to respond to habit breaking.
 The following methods for breaking the habit are
listed in the order in which they should be used:

Treatment of digit-sucking habits,
BOS guidelines 2000
A. Non-physical methods
I. Explanation.
II. Reward.
III. Habit reversal.
IV. Teach the child to carry out alternative activities when they have the urge to suck the
digit.
A. Physical methods
 Reminder therapy like finger bandage, finger paint or thermoplastic finger post
A. Intra-oral appliances
I. Have been shown to be effective within 10 months.
II. They must be fitted with the full understanding and co-operation of the child and
must not compromise compliance with any future orthodontic treatment.
III. Fixed appliance like palatal appliance with crib.
IV. Removable appliance.
V. Functional appliance can stop habit .

Habit Breakers Appliances
1. Vertical Crib
 Restrain the tongue from excessive anterior movement
or thumb sucking.
 A .040” support arch wire is soldered to bands on the
first molars.
 A vertical Cage is extended just behind the lower
anteriors.

Habit Breakers Appliances
2. Flat Crib
 For Thumb Sucking.
 Wires are placed across the palate parallel to the
occlusal plane to prevent the thumb from contacting
the rugae.
 This appliance is also less noticeable than a vertical
Habit appliance.

Habit Breakers Appliances
3. Rake
 For patients that seem to get around all the other
designs.
 Vertical rake is extended just behind the lower
anteriors.

Habit Breakers Appliances
4. Pearl
 Restrain the tongue from excessive anterior movement.
 A vertical cage is extended just behind the lower anteriors
to prevent the patient from tongue thrust.
 A pearl is added in the vault of the palate to retrain the
tongue.

Myotherapy
 It aims to alter resting tongue and lip posture.
a. Exercise.
b. Appliances.

MYOTHERAPY Exercises
1. Ask the patient to hold a piece of paper between the
lips.
2. The patient is instructed to practice correct swallowing
pattern by placing the tip of tongue on the palate,
close teeth, close lips and swallow with tongue in
that position. After the new swallowing pattern learned
on the conscious level, it is necessary to reinforce in
subconsciously. Flat, sugarless fruit drops are used to
reinforce subconsciously by asking the patient to hold
fruit drops against the palate.
3. Ask the patient to squeeze teeth together as hard as
possible for 15 secs, relax and repeat three times for total
of one minute. This exercise should be done five times a
day (Clenching exercises).

Myotherapy appliances
1. Spring-loaded bite block, the spring-loaded bite block has helical springs
that are placed both lingually and buccally between the first premolar region
and the last molar region. The ends of the springs are embedded occlusally
in the molar regions of the acrylic part of the device. The upper and lower
acrylic occlusal blocks are connected by palatal and lingual wires, which are
activated to a force of 450 g bilaterally. Patients are instructed to use the
appliance for an average of 16 h daily
2. Passive posterior bite-blocks, are functional appliances that are used to
open the bite 3–4 mm beyond the rest position. In growing patients, this
inhibits the increase in height of the buccal dentoalveolar processes, thus
preventing a downwards and backwards rotation of the mandible. It also
allows differential eruption to occur as the labial segments can erupt
unhindered, hence closing the AOB.
3. The functional regulator appliance (FR IV).
4. TwinBlock with modifications.

Frankel FR- IV
 It establishes the mandible forward rotation with
posterior edges of buccal shields as rotational centers.
 Anteriorly: the force of anterior vertical muscle chain
being strengthened by lip seal exercise raises the
mandible.

FR -IV

FR-IV
 OWEN s modification of a function regulator differs
from other Frankel appliances by:
a. Addition of posterior acrylic bite blocks to arrest
molar eruption.
b. Has headgear tubes that accept a facebow for an
occipital pull headgear, which provides the appliance
with positive control of the posterior maxilla.

Frankel IV

Frankel IV
 Cochrane review, by Oliveira, in 2007showed that
there is weak evidence that the interventions FR-4
with lip-seal training and palatal crib associated with
high-pull chin cup are able to correct anterior open
bite.

Twin blocks with modifications
1. Thick Twin block appliance: The ramps measure 5
mm to 8 mm in thickness in the premolar region.
Twin block with headgear to upper 1st molar.
2. Vertical elastics to upper and lower posterior
premolar regions.
3. Repelling rare earth magnets in the occlusal bite
blocks

 Twin-Block with posterior bite blocks :
 Bite anterioposteriorly is irelevent to the deep bite
correction
 Bite is be opened above the normal resting vertical
dimention.
 Blocks on molars prevent their eruption, and the
opening of the bite stretch the muscles.

Extraoral Traction
1. Vertical pull chin-cup
2. High-pull headgear applied to the maxillary molar
teeth worn for 14 hours per day has been used to
inhibit eruption of the posterior teeth and hence
limit vertical growth
 High pull headgear to a maxillary splint.
 High pull headgear to buccal splint.
 Headgear can be applied directly to the upper molar
bands of a fixed appliance

Fixed Appliances
1. Extraction of terminal molars
2. Bracket set up (more gingival at anterior teeth, reduced
canine tipping)
3. Wire bending to allow incisor extrusion
4. Tongue timer which act as a tongue thrust breaker
5. Vertical intermaxillary elastics to extrude the anterior
teeth. Should not be used if the etiology is primarily
skeletal.
6. Segmental arch mechanics to extrude the incisor similar
to Rickets mechanics.
7. Kim mechanics & Modified Kim mechanics.

Kim mechanics
 Increased curve of Spee in the maxillary arch and a
reverse curve of Spee in the mandibular arch
combined with anterior elastics.
 Size of anterior elastic is 3/16 heavy
 Force is 50g when closing
 150g when opening.

Molar intrusion using skeletal
anchorage
 LikeDental implants, mini-plates, mini-screws
,ankylosed teeth (Cousely 2008 use TPA with two
palatal TAD for posterior teeth intrusion, while Etilita
et al 2012 use TPA with two buccal TAD). Park et al
(2008).
 Intrusion of the molars is best suited to skeletal open
bite patients who show long face types with class 1 or
mild class 2 skeletal patterns whereas in class 3 open
bites, the class 3 malocclusion would get worse as the
anterior open bite closed

 Patients who do not show sufficient incisor exposure
should not be treated by molar intrusion, making the
more conventional method of incisor extrusion a more
suitable option for open bite correction
 This can be achieved by
 placing miniscrews on both the buccal and palatal,
 using a transpalatal bar or a splint
 An alternative design of splint

Mid Palatal Implant

Disadvantages of buccal implants
1. The inter-radicular space between the first molar
and the second molar is very small.
2. In open bite cases, as the posterior teeth being
intruded, the screw becomes closer to the alveolar
crest and the periodontal membrane.

Disadvantages of buccal implants
 In most of cases, the inter-radicular space between 6
and 7 is narrow.
 Then, it is inevitable to place a mini-implant between
5 and 6.
 The mechanical efficiency to intrude the posterior
teeth will be decreased & Possibility of Root trauma is
high.

Orthognathic Surgery
 Where there is an obvious step in the occlusal plane,
two piece maxilla.
 No step, one piece maxilla.
 Subapical osteotomy of the anterior (Kole technique) or
posterior segment (Schuchart technique) depend on the
etiology.
 Recently Bisase 2009 recommend anticlockwise
rotation of BSSO with rigid fixtion.

Stability of AOB
 In general: AOBs treatment is stable in approximately 80%
of treated cases with slightly better with surgical treatment
than non-surgical (5% differences).(Huang, 2002)
 Extraction: There is also evidence of greater stability of
open bite correction when orthodontic treatment is
undertaken with extractions (Janson et al., 2006)
 Extrusionorintrusion: In treatment resulting in molars
intrusion, the rate of relapse ranges from 17 to 30%: whilst
in treatments with incisor extrusion, relapse may be even
greater, reaching sometimes 40% of treated cases. (Suguwara 2011)

Causes of relapse
a. Continued unfavorable posterior mandibular growth
rotation
b. Unfavorable tongue position
c. Continued habit
d. Excessive extrusion of incisors
e. Relapse after surgery

Management of relapse
1. Overcorrection
2. Using High-Pull headgear attached to a URA
3. Retainer with passive bite blocks, which
supposedly place intrusive forces on the posterior
teeth, could be used & should be continued until
facial growth has almost ceased and this is often well
into late teens.
4. Some recommend lip and tongue muscle
exercises.

Skeletal class 2 with Long Face
 Can be treated successfully by the intrusion of the
posterior teeth as this would produce a closing
counterclockwise rotation of the mandible with a
shortening of the anterior facial height and a
correction of the open bite, in addition to the
reduction of OJ.
 In grower with High-Pull Headgear.
 In non-grower By TADs

Case report of class 2 high-angle in
12 year old patient

Classification of deep bite
Classification
Developmental deep
bite
Skeletal deep bite
(horizontal growth pattern)
Dento-alveolar deep
bite
Inter occlusal clearance
(functionally a pseudo
deep over bite)
supra occluded incisors
Acquired Deep Bite
Lateral Tongue Thrust ,
Infra Occluded
Posterior Teeth e.g.
class II div 2
Early loss of Deciduous
Teeth, Tipped
Contiguous Teeth
(Acquired Secondary
Deep Over Bite)
Wearing of Occlusal
Surface or Tooth
abrasion

Dento-aleveolar
Skeletal

Features of low angle or short face
syndrome
 Skeletal features:
a. Short lower third of the face.
b. Class II skeletal relationship.
c. Long maxilla.
d. Short mandible.
e. Broad square facial type.

Features of low angle or short face
syndrome
 Soft tissue features:
a. Increased exposure of maxillary anterior teeth and gingiva at
rest and smiling.
b. Competent lip.
c. Acute LMA & NLA.
d. High lower lip line.
e. Hyperactive mentalis.
f. Hypertrophied masseter.
g. Prominent chin.

Features of low angle or short face
syndrome
 Intraoral features:
a. Deep bite.
b. Class 2 Dev2 tendency.
c. Reduced overjet.
d. Wide upper arch.
e. Lower incisor trapping behind upper incisors.
 Growth feature:
 Usually anterior growth rotation.

Cephalometric feature
a. UAFH-LAFH ratio: less than 0.65 are considered to
be poor risks for conventional orthodontic treatment
alone.
b. Bjork’s seven features of posterior growth
rotation.
c. Jarabak ratio:
 PFH:AFH, 59 – 63% is normal; if > 64 low angle case
then the case is deep OB; if < 58 then the case is high
angle case, reduced OB.

Aetiology
deep
overbite
Skeletal
Factors
Soft Tissues
Dental
factors
Growth
Factors

Skeletal Factors
1. Antero-posterior problem:
Class II skeletal pattern with loss of occlusal contact
allowing the incisors to overeupt or the mandible to
rotate anteriorly.
2. Vertical problem:
A reduced lower face height in conjunction with a class II
jaw relationship often results in the absence of an
occlusal stop to the lower incisors, which then continue
to erupt leading to an increased overbite which
exaggerated by anterior growth rotation of the mandible.

Growth Factors
 In forward growth rotation and loss of incisor stop an
increased overbite will become worse unless the
incisors have an occlusal stop.

Soft Tissues
a. High lower lip line: The higher the lower lip line, the
more retroclined the upper incisors and the deeper the
overbite.
b. Hyperactive or “strap- like” lower lip.
c. Hyperactive Mentalis muscle: causing retroclination of
the upper incisors and then increase in the OB.
d. Hyperactive Masseter muscle.

Dental factors.
 Diminution of palatal surface (cingulum) of the
upper incisor crowns.
 Increased Incisors height.

Iatrogenic Factor
 In the case of treating Class II division 1 and instead
of finishing the case into Class I, it is finished into
Class II division 2 causing deep incisor overbite.

Management of Low Angle cases

Treatment modalities in growing
and non growing patients.
1. Growing patients:
a. Intrude anteriors.
b. Extrude posteriors.
c. Combination of posterior eruption and anterior
intrusion.
2. Non growing patients (little or no growth expected):
a. Orthognathic surgery.
b. Intrusion of anteriors (posterior extrusion invariably
relapses).

Soft Tissue consideration

Depending on Inter occlusal space

Dental and Skeletal consideration

Considering Growth pattern

Mechanics for overbite reduction

Mechanics for
overbite
reduction
Extraoral traction Dahl appliances
Removable
Appliances
Fixed appliance
Bracket setting
Intermaxillary
mechanics
Fixed anterior
bite planes.
Archwires:
Rocking chair
NiTi arch wires
Segmented
Burstone Arch
Wires mechanics
Rickett’s utility
arch
Absolute
Anchorage
Orthognathic
Surgery

Removable Appliances
Anterior Bite Plane
Indications:
a. Growing patient.
b. With a short lower facial height.
c. Excessive curve of Spee.
d. Other uses include protection of the lower incisor
brackets from being debonded.

Extraoral traction
1. J hooks: (Linge and Linge 1983 show that J hook
cause root resorption). Degushi 2008 compared TAD
with J hook for intrusion and found the result is 3.1
and 1.3mm respectively.
2. Cervical pull HG to molars

Functional Appliances
 The modes of action in reducing the OB are:
a. By allowing the posterior teeth to erupt either during the
active functional appliance through relieving of the
acrylic from the lower part of the TB or during transient
period through the use of steep and deep URA.
b. Through changing the direction of growth pattern
c. By some proclination of the lower labial segment may
occur

Fixed appliance setting
1. Increase mesial angulation of the upper canines.
2. Bracket Positioning
3. No laceback or cinch back
4. Banding second permanent molar. This means:
 Additional vertical posterior anchorage
 Molar therefore a more effective wedge in extrusion is
more distal and the occlusion.

Rocking chair NiTi archwire
 It acts by intrusion of anterior teeth.
 Extrusion of posterior teeth.
 Proclination of anterior teeth.
 It can be used to treat AOB with Kim mechanics.
 Earlier engagement of brackets with a rectangular wire is
possible, which may speed overbite reduction.
 long range of action

Disadvantages of Rocking chair NiTi
arch wires
 Molar rotation distobuccally.
 Molar rolling buccally.
 Premolar expansion.
 Incisor proclination.
 Asymmetric bite opening sometimes occurs.
 Contraindicated in extraction cases(difficulty of space
closure).

Segmented Burstone Arch Wires
mechanics
 AW which is a segmented base arch wire (so that there is no
connection along the arch between the anterior and posterior
segments) and an auxiliary depressing arch.
 The buccal segments are first aligned, and then stabilised using a
full dimension rectangular arch wire. The same for anterior segment
 In addition to this, a heavy lingual arch is used to connect the right
and left posterior segments.
 An auxiliary depressing arch is then placed in the auxiliary tube on
the first molar and is used to apply force against the anterior segment.
 It is recommended that no more than the four incisors should be
incorporated in the intrusive segment, since if the canines were also
included, this would shift the anchorage balance unacceptably towards
distal tipping of the buccal segment teeth.
 018x.025ss wire with a two and a half turn helix.
 .019x.025 TMA without a helix.

Segmented Burstone Arch Wires
mechanics
 The wire should lie just gingival to the incisor teeth when
passive, and applies a light force of 10-15g when activated.
 The Burstone intrusion arch is tied beneath the brackets, not
into the bracket slots, which are occupied by the anterior
segment wire.
 It still has the effect of wanting to tip the incisors forward as they
intrude, but two strategies may be employed to prevent this:
 The arch wire may be tied back against the posterior segment –
however, this can put some strain on the posterior anchorage.
 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.

Segmented Burstone Arch Wires
mechanics
 It still has the effect of wanting to tip the incisors forward
as they intrude, but two strategies may be employed to
prevent this:
a. The arch wire may be tied back against the posterior
segment – however, this can put some strain on the
posterior anchorage.
b. 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.

Rickett’s utility arch
 step-down bends
 labial root torque to control the inclination of the teeth as the
incisors move labially while they intrude.
 Indications for segemental archwires:
a. Adults.
b. Deep overbite with the incisors are upright and the canines
distally angulated and an intrusive force anterior to the
centre of resistance of the incisors in the early stages is quite
helpful.
c. Highly positioned canines with overerupted incisors.
d. Gummy smile.
e. Orthodontic decompensation for AOB case treated by
segemental surgery.

 Advantages of segemental archwires:
a. A long range of action, because of the long inter-
bracket span.
b. More easily estimated biomechanical effects.
c. Frictionless.

 Disadvantages of segmental mechanics:
a. Complexity of fabrication.
b. Less ‘fail-safe’ effect if the case is unsupervised for a period.
c. Oralhygiene difficulties and patient discomfort if the wires impinge on the
mucosa.
d. Poorercontrol of overall arch form; bypass arch systems limit the amount
of true intrusion that can be obtained:
 Extrusion of the first molar can occur through distal tipping of molars as it is
the only tooth available as posterior anchorage – high-pull headgear may need
to be used, especially in non-growing patients.
 the intrusive force against the incisors is applied anterior to the centre of
resistance – causes incisors to tip forwards as they intrude.
Rickett’s utility arch

Functional appliances
 For class 2 and reduced facial height.
 Treatment of choice when having growing class 2
patient with deep bite.
 Proclination of lower incisors reduces deep-bite.
 They might change the direction of grwoth to
downward-forward direction.

Class 2 elastics
 Helps in lower molar extrusion.
 Although can cause upper incisors to retract, the effect
is much less than lower molars extrusion, since they
are closer to the hing axes.
 Upper rect. Steel can reduce the effect of retroclination
of upper incisors.

Surgery
 3 point landing, followed by premolar extrusion.
 Segmental surgery eg: Kole procedure.

If a growing patient presented to you with:
 Low angle class 2?
 High angle class 2?
 Low angle class 3?
 High angle class 3?

Stability of OverBite
1. Avoiding change in the facial height in non-growing.
2. Long term retention if LLS proclined.
3. Amount of the OB at the start.
4. Normal InterIncisal angle.
5. Normal lower incisor edge to centroid.
6. Build up diminutive cingulum plateau.
7. Vertical height growth continue in teenager so the
use of URA with ant bite plane as part time use in
retention.