deep overbite by almuzian

UNIVERSITY OF GLASGOW

Orthodontic management of deep overbite

Personal note

MOHAMMED ALMUZIAN

1/1/2013

.

Table of Contents

Definition.......................................................................................................................4

Prevalence.....................................................................................................................4

Classification.................................................................................................................4

True rotation, matrix rotation & apparent total rotation as described by Bjork 1969...7

Features of low angle or short face syndrome...............................................................8

Aetiology deep overbite,.............................................................................................11

Indication for treatment of deep OB............................................................................14

Principles of deep incisor overbite reduction..............................................................14

Consideration factors for the method of treating DOB...............................................15

Mechanics for overbite reduction................................................................................16

In details......................................................................................................................19

Removable Appliances................................................................................................19

Indications...................................................................................................................19

Extraoral traction.........................................................................................................19

Dahl appliances...........................................................................................................20

Begg Technique and Tip edge Technique,..................................................................20

Lingual appliance........................................................................................................21

Fixed appliance setting................................................................................................21

Fixed appliance with continuous Arch Mechanics......................................................21

Auxiliary appliances....................................................................................................24

Functional Appliances.................................................................................................24

Sectional archwires and auxiliary archwires...............................................................25

Mohammed Almuzian, University of Glasgow, 2013

Advantages of segemental archwires..........................................................................28

Disadvantages of segmental mechanics......................................................................28

Indications for segemental archwires..........................................................................29

Investigations comparing reverse curves of Spee AW (modified Tweed technique) to

Burstone mechanics for overbite reduction.................................................................29

Investigations comparing reverse curves of Spee AW (modified Tweed technique) to

sectional arches for overbite reduction (Rickett utility arch)......................................30

Absolute Anchorage....................................................................................................30

Surgical treatment of the Deep Overbite.....................................................................30

Stability of OB correction...........................................................................................31

Summary of the evidences..........................................................................................31


Deep overbite

Definition

Overbite can be described as the vertical overlap of the upper and lower

incisors measured parallel to occlusal plane with the posterior teeth on

occlusion when viewed anteriorly. (BSI 1983).

OB measured perpendicular to occlusal plane in mm or ratio.

Prevalence

Deep bite prevalence is 8% in US

Blacks are 10 times more likely to have an AOB

Deep overbites are 6 times more frequent in whites.

Classification

1. Skeletal

2. Dental

3. Averaged value when the upper incisors teeth overlap one third to a half

of the lower incisors.

4. Increased

5. Reduced,

6. Complete when there is contact between the lower incisors and either

the upper incisors or the soft tissues,

7. Incomplete which at its extremities no vertical overbite exists and

indeed an anterior open bite can exist.


Type of growth of the mandible

Nielsen et al 1991

1.Normally

A. The direction of condylar growth is vertical, with some anterior

component,

B. Always there is a balance between APH and PFH growth to achieve

normal FH. If this is lost then either long or short face might develop

C. AFH depend on the

1. eruption of the maxillary and mandibular posterior teeth

2. growth at the posterior dentoalveolar area

3. The amount of sutural lowering of the maxilla.

4. Surface remodelling at the anterior region of the mandible

D. PFH depend on the

1. Downward growth of posterior cranial fossa

2. Lowering of the temporomandibular fossae

3. Condylar growth.

4. Surface remodelling at the posterior region of the mandible

2.In anterior or forward rotation

If the incisor occlusion is stable, the overbite remains unchanged during

the growth period & the fulcruming point is located at the front teeth.

If the incisor occlusion is unstable, the fulcruming point is located

further back along the occlusal plane. In this situation the bite normally

becomes increasingly deep over time as the result of greater posterior face

height increase in combination with lack of anterior tooth contact. This

deterioration of the occlusion is most pronounced during puberty when


growth intensity is at its greatest, but continues throughout the growth

period. Patients with a pronounced tendency to anterior growth rotation and a

deep bite should therefore be treated early and the occlusion supported

throughout the growth period. Retention, especially in the mandibular arch,

must also be maintained until mandibular growth is completed.

The erupting dentition in this type of mandibular growth

characteristically undergoes a considerable amount of mesial migration of

both the maxillary and mandibular teeth with some degree of proclination of

the mandibular incisors. Where the amount of mesial migration of the lower

posterior teeth does not equal the advancement of the incisors by proclination

(due to trapping behind upper incisors), secondary crowding of the front

teeth frequently develops.

3.In posterior rotation of the mandible

If dentoalveolar growth is greater than vertical condylar growth, the

resulting change in mandibular position is back ward or posterior rotation of

the mandible. The increase in AFH is greater than in PFH, the mandible

rotates posteriorly with the fulcrum at the condyle.

This posterior growth rotation may result in an anterior open bite,

depending on the extent of vertical dentoalveolar compensation.

The associated dental eruption pattern of the posterior teeth is generally

distal & vertical and in some instances the anterior teeth may even become

more retroclined with time. Late crowding is common finding in this pattern

of growth due to soft tissue maturation.

Because the centre for the growth rotation is located near the

mandibular condyles, treatment should be postponed until after puberty or at

least until the potential for backward or posterior rotation is reduced. The

reason for late treatment is that


A. The tendency to extrude the posterior teeth decreases when there is less

active growth.

B. In addition when treated orthodontically these patients are at increased risk

for further mechanically induced posterior rotation by acceleration of their

molar eruption and require careful control.

C. The increased risk of extrusion in these patients is associated with their

weaker masticatory musculature making vertical control an important

consideration.

True rotation, matrix rotation & apparent total rotation as described by Bjork

1969

The actual rotation or total rotation in humans is generally masked on

average by 50% surface modelling within the jaws.

In a recent study of non-human primates, it was found that this

modelling or intramatrix rotation in the Rhesus monkey masked the rotations

by about 75% in the maxilla and 90% in the mandible.

This surface modelling causes, in most instances, the lower border of

the mandible to appear almost unchanged in its inclination to the cranial base

and has led to misinterpretations of the actual growth changes and tooth

movements in humans.

An example of this is seen in Figure

below where the change in mandibular

lower border inclination over time, the so-

called matrix rotation, was -7.3° whereas

the actual, or true rotation, was as much

as -16.4° anteriorly


Features of low angle or short face syndrome

1. Skeletal features:

Short lower third of the face,

Class II skeletal relationship

Long maxilla

Short mandible

Broad square facial type.

2. Soft tissue features:

Increased exposure of maxillary anterior teeth and gingiva at rest and smiling

Competent lip

Acute LMA & NLA

High lower lip line

Hyperactive mentalis

Hypertrophied masseter.

Prominent chin

3. Cephalometric feature.(this is also predictors for skeletal deep bite)

i. Increased MMPA

ii. UAFH-LAFH ratio: Nahoum (1975) believed that patients with a dental

open bite and a UAFH-LAFH ratio of less than 0.65 are considered to be

poor risks for conventional orthodontic treatment alone.

iii. Bjork’s seven features of posterior growth rotation (Bjork, 1969)

The condyle is inclined forward;


The mandibular canal has a curvature greater than the mandibular contour;

The lower border of the mandible is rounded anteriorly and concave at the

angle, due to bony deposition along the anterior region and Symphysis as well

as resorption below the angle;

The symphysis is inclined forward within the face and the chin is prominent;

The interincisor angle increased

Interpremolar and intermolar angles are all increased;

The anterior lower face height is reduced with a tendency towards an increased

overbite.

iv. Jarabak ratio, Jarabak, 1972

PFH:AFH, 59 – 63% is normal; if more than 64 low angle case then the

case is deep OB; if less than 58 then the case is high angle case, reduced

OB

v. Reduced dentoalveolar height in molar region and increased dentoalveolar

height in incisor region due to strong muscle allowing molar eruption.

(Neilsen, 1991).

vi. The degree of dentoalveolar compensation or dysplatic

First described by Bjork 1969 and later discussed by Solow. These can be measured

through the following:

In the maxilla, the maxillary zone, measured as the angle between the palatal

plane (ANS-PNS) and the maxillary occlusal plane (mean 10°±3 ), describes

the extent of compensatory or dysplastic development.

In the mandible, the mandibular zone, measured between the mandibular plane

(GO-GN) and the mandibular occlusal plane (mean 20°±4°), similarly

describes possible compensation.


If one or both of these measurements are increased in a patient with an

increased vertical jaw relation, favorable dentoalveolar compensation is

indicated.

On the other hand, if these measurements are normal or reduced in the same

patient, either no compensation or dysplastic development has taken place.

This will help in determine the type of treatment. Eg. If the high angle case

has no compensation or has dysplastic development, then treatment can be

achieved through orthodontic treatment to initiate this compensation, but if the

compensation is already present then the case is surgical.

4. Intraoral features

Deep bite

Class 2 D2 tendency

Reduced overjet

Wide upper arch

Lower incisor trapping behind upper incisors

5. Growth feature

Usually anterior growth rotation

6. Path of closure

Usually normal or may be associated with posterior mandibular displacement

7. IOTN and OB

Overbite measured from any of the lateral or central incisors with the

largest vertical discrepancy is recorded.

It is also important to note if there is any gingival or palatal trauma as a

result of the deep overbite


Overbite and Open bite

Overbite Open bite

Grade and

qualifier

Grade and

qualifier2f Increased greater Than Or

equal to 3_5 mm

2e Anterior or posterior

open bite I mm • .2 mm

3f Deep overbite complete on

labial or palatal 'issues but no

Trauma

3e Anterior or posterior

open bite 2.1 mm — 4

mm

4f Increased and complete

overbite with labial or palatal

trauma

4e Extreme lateral open

bites greater than 4 mm

Aetiology deep overbite,

Naini 2006, dental update

Skeletal Factors.

Soft Tissues

Dental factors.

Growth Factors

Iatrogenic Factor

I. 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. (Mitchell

1996).

II. Growth Factors

In general the vertical growth continue to late age adulthood with the maxilla

normally rotate upward and forward and mandible upward and forward in

80%. In forward growth rotation and loss of incisor stop an increased

overbite will become worse unless the incisors have an occlusal stop.

III. Soft Tissues

a. High lower lip line, Nicole (1954) was the first to suggest that a

high lip line was a feature of Class II division 2 malocclusion and deep bite,

and this was confirmed by Ridley (1960). The higher the lower lip line, the

more retroclined the upper incisors and the deeper the overbite.

b. Hyperactive or “strap- like” lower lip

It mainly cause retroclination of the lower incisor with associated

LLS crowding and deep OB and increased OJ.

Hyperactive lip bashes the lower incisors and the giggling forces

leads to bone loss and periodontal breakdown with loss of attachment.

Methods of treatment tried with hyperactive lip:

1. Mentalis myotomy,

2. Lip bumpers to stretch muscle fibres,

3. If the lower incisors moved forward the using a permanent rigid retainer

is mandatory

c. Hyperactive Mentalis muscle causing retroclination of the upper

incisors and then increase in the OB

d. Hyperactive Masseter muscle,


Adults with reduced anterior face height have increased bite force

and also a different composition of muscle fibres in the masseter,

which implicates muscles as a primary cause of malocclusion. Hunt

1992 found that long face syndrome has predominantly collage fiber

type 1 which is weak and long acting while short face syndrome has

more type 2 collagen fibres which is heavier and short acting.

Benington 1999 showed large muscle fibres in deep bite and small size

muscle fibres in AOB

However (Proffit & Fields, 1983) believe that this muscle change is

a result from malocclusion.

IV. Dental factors.

1. The eruptive potential of the incisors with decreased inclination of

the incisors

2. Diminution of palatal surface (cingulum) of the upper incisor crowns

3. Abnormal Crown-root angulations

4. Increased Incisors height (Mills 1989)

5. Thin incisors

NB: there are some dental feature associated with deep OB but

cannot be considered as a causative factors including:

I. increased Inter-incisal angle, but this not always the case, because in

class 3 cases, the II angle is increased but the OB is reduced (Mills, 1989)

II. abnormal Incisor edge-centroid relationship (Houston, 1972)

V. Iatrogenic Factor

This is as 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.


Extraction of the primary canine will result in deep overbite. Stephan

1992.

Indication for treatment of deep OB

1. In primary nor mixed dentition: No treatments is indicated in

primary nor mixed dentition since most of the deep bite case resolved with

growth.

2. In permanent dentition , treatment is indicated in the following

scenarios:

Traumatic OB

Functional problems

Aesthetic problems (especially if it is associated with increased

incisor and gingival show)

If it interferes with OJ correction.

Principles of deep incisor overbite reduction

1. Levelling of the arch through molar and premolar eruption and

extrusion (relative intrusion). Keeping in mind that in growing

patient, the condyle will compensate the extrusion and maintain the

AP relationship, but in the adult the condyle not compensate for that,

however, the muscle activity adapt very well to the new position and

help in the stability (McDowell & Baker, 1991). In adults, the slight

hinging open of the mandible, associated with molar extrusion,

seems to be stable. This may be due to the tendency to slight

continued vertical growth found in adults by investigators such as

Behrents (1986).

2. Incisor and canine intrusion (true intrusion) it is indicated in the

following cases:


Adult patient

Excessive maxillary incisors showing at rest

Long lower facial height.

Over erupted incisors

If elongation of the teeth after loss of periodontal support has occurred.

3. Proclination of lower incisor. This effect has been analysed by

Eberhart et al (1990) who, for example, stated that 5 degrees of

incisor proclination would reduce the overbite by 1 mm on average.

4. Distal tipping of posterior teeth (up righting of posterior teeth)

5. Surgery to change AP and vertical problems.

Consideration factors for the method of treating DOB

Age

Patient compliance

OH

Patient concerns

Faial profile

Vertical height relationship

Amount of incisor show

Gingival thickness on the labial surface of incisors

Incisor inclination

Intra-arch

Incisor relationship.

In details


1. Age and growth remaining of the patient which may affect the degree of

incisor show (it is preferable to accept some incisor show in growing patient

since soft tissue maturation would mask some of the underlying problems) or

the use of ABP according to the growth status

2. Patient compliance and OH

3. Patient concerns

4. Vertical height relationship. eg in high angle case it is better to avoid

posterior teeth extrusion.

5. Faial profile: avoid proclination of incisors in full or convex profile.

6. Amount of incisor show. The incisors show depend on the following

factors:

Lip length

Crown height

Lip activity

Gingival height and level

Anterior maxillary height (VME)

7. Incisor inclination

8. Gingival thickness on the labial surface of incisors

9. Intra-arch relationship like OJ, MR, crowding (if the arch is crowded

or the OJ is reduced then reducing the OB by proclination of incisors is

preferable)

10. Incisor relationship. In class 2 division 1 the aim of reducing OB is by

intrusion of incisors, extrusion of molars. While in class 2 division 2 the aim

of reducing OB is by proclination of incisors as well as intrusion of incisors,

extrusion of molars.


Mechanics for overbite reduction

1. Extraoral traction A. HG

B. J hooks

C. HG-tandem

2. Removable

Appliances

A. ABP

B. Functional Appliances

3. Dahl appliances Removable chrome bite plane

Fixed bite plane (essentially

Maryland/Resin-bonded bridge retainer

wings otherwise called metal palatal

veneers)

Porcelain palatal veneers

Direct composite veneers

Definitive or temporary crowns.

4. Begg appliances

5. Tip edge appliances,

6. Lingual appliance

7. Fixed appliance A. Bracket setting Bracket

Positioning

Increase mesial

angulation of the

upper canines.

Partial ligation of

the distally

inclined canines

Banding second

permanent molar


No laceback

No cinch back

B. Fixed anterior bite

planes.

Composite

Metal

C. Intermaxillary

mechanics

Class 2 bite corrector

Class II inter-maxillary

elastics

Archwires:

A. Fixed appliance

with continuous

Arch Mechanics

Tweed mechanisim

Modified Tweed

mechanics

Using localised intrusion

bends

Archwires with step-

down T loops or step in

SS arch wires

Counterforce/ Rocking

chair NiTi arch wires.

(Modified Tweed

mechanics)

Anchor bend approach

Auxiliary levelling arch

B. Segmented

Burstone Arch

Wires mechanics

C. Rickett’s utility

arch

1.

8. Absolute Anchorage

9. Orthognathic Surgery


In details

Removable Appliances

Indications

1. Growing patient

Providing that the rate of molar eruption does not exceed the relative

rate of vertical condylar growth, there should be no backward mandibular

rotation. However he stability of posterior (extrusion may be questionable in

non-growing patient, but, the muscle activity adapt very well to the new

position and help in the stability (McDowell & Baker, 1991)

When the rate of vertical growth of the buccal segments is greater than

the vertical condylar growth however, a backward mandibular rotation will

occur. Also, in non-growing patient, the molars will tend to reintrude under

the forces of the occlusion once the appliance is withdrawn. This tendency

can be resisted to a degree if the treatment creates a stable incisor

relationship.

2. With a short lower facial height,

3. Excessive curve of Spee,

4. Moderate-minimal incisor display because increase in the interlabial

gap which may worsen the gingival show.

5. Other uses include protection of the lower incisor brackets from being

debonded

Extraoral traction

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.

Cervical pull HG to molars


Dahl appliances

Originally described by Dahl in 1970.

The Dahl appliance is a removable or cemented cobalt chrome

appliance which covers the palatal surfaces of the maxillary anterior teeth.

This allows contact of the mandibular anterior teeth with the appliance,

holding the posteriors out of occlusion.

This, in turn, promotes intrusion of the anterior teeth and eruption of the

posteriors, thus providing space anteriorly.

It has been shown in an implant-cephalometric study to result in

intrusion of the anterior teeth by an average of 1.05 mm, and eruption of the

remaining teeth, averaging 1.47 mm after 6–14 months, without causing

undue incisor proclination or TMD problems.

It reduces nocturnal bruxism;

Dhal appliance is not successful in adult as the free-way is increased in

this group of patient due to dental wear.

Current types of Dahl 'appliances' Briggs 1997

1. Removable chrome bite plane

2. Fixed bite plane (essentially Maryland/Resin-bonded bridge

retainer wings otherwise called metal palatal veneers)

3. Porcelain palatal veneers

4. Direct composite veneers

5. Definitive or temporary crowns.

Begg Technique and Tip edge Technique,

A 0.016 stainless steel high tensile strength wire is used. If the

alignment of the anterior teeth is required, then an auxiliary 0.014 NiTi can


be used. Circle hooks are placed mesial to the canines and an Anchor bend

(2-3mm) in front of the first molar to intrude the incisors. Class II elastics

(60gm, yellow) to extrude lower molars are used. Extrusion of the upper

incisors by the class II elastic would be opposed by anchor bend in the upper

arch wire while the lower posterior teeth will allow to erupt and LLS procline

and thus the overbite will be reduced.

Lingual appliance

With lingual appliances, vertical control, as in levelling the curve of Spee or

controlling the overbite, is clinically more efficient than in edgewise labial or

conventional lingual appliances because

With a ribbon-wise configuration the big dimension of the archwire

(0.025 inch superior-inferiorly) corrects the vertical plane

Also because the close proximity of the force application to the centre

of rotation and root

The anterior bite effect.

Fixed appliance setting

1. Increase mesial angulation of the upper canines.

2. Bracket Positioning

3. Partial ligation of the distally inclined canines

4. No laceback or cinch back

5. Banding second permanent molar. This means

Additional vertical posterior anchorage

Molar extrusion is more distal and therefore a more effective wedge in

the occlusion.


Fixed appliance with continuous Arch Mechanics

1. Fixed appliances with continuous arch wires for flattening of the

COS using rigid aw with or without reverse curve

This type of levelling can be accomplished with continuous arch wires,

simply by placing an exaggerated curve of Spee in the maxillary arch wire

and a reverse curve of Spee in the mandibular arch wire.

If using an 0.22” slot bracket, initial alignment is carried out using a

0.0175 twist flex or A 0.016” Niti.

This is then followed by a 0.016SS wire with a reversed or accentuated

curve, and then by an 0.018SS wire to complete the levelling (Proffit, 2000).

Rectangular AW can be used too: It creates torque to move the incisor

roots lingually and Al-Qabandi et al. (1999) carried out a prospective

randomised clinical study to compare the effects of rectangular and round

arch wires in levelling the curve of Spee. They found no significant

difference in proclination between these two groups.

2. Using localised intrusion bends

3. Archwires with step-down T loops or step in SS arch wires:

indicated when there is a step between the anterior and posterior occlusal

planes, in cases with moderate-to-minimal incisor display, and Class I

occlusions.

4. Counterforce/ Rocking chair NiTi arch wires. (Modified Tweed

mechanics)

Mode of action of Counterforce/ Rocking chair NiTi arch wires

1. It acts by intrusion of anterior teeth

2. Extrusion of posterior teeth

3. Proclination of anterior teeth


4. Study by Clifford et al (1999) indicating that with a reverse curve of

Spee in the lower archwire, the second molars in fact intrude rather than

extrude.

Advantages and indications of Counterforce/ Rocking chair NiTi arch wires

1. Earlier engagement of brackets with a rectangular wire is possible,

which may speed overbite reduction.

2. Used with small inter-bracket spans with long range of action

3. Simultaneously reducing overbites and closing spaces without adverse

tipping and “lingual collapse” into extraction sites

4. It can be used to treat AOB with Kim mechanics

Disadvantages of Counterforce/ Rocking chair NiTi arch wires

1. Molar rotation distobuccally

2. Molar rolling buccally

3. Molar intrusion with premolar expansion

4. Incisor proclination

5. Asymmetric bite opening sometimes occurs

6. Hypothetically, 15 degrees of (unwanted) labial crown torque would

result from leaving a curve of Spee of 5 mm at its greatest depth in a full-size

archwire (0.022 x 0.028") to go completely passive.

The means of preventing unwanted labial tipping of lower incisors

during levelling of the curve if Spee are therefore:

1. a lower incisor prescription with lingual crown torque

2. lingual crown torque in the rectangular wire

3. intra-arch traction This requires space in the lower arch usually

via extractions


4. class 3 elastic This requires cooperation and may cause unwanted

anchorage loss in the upper arch.

Auxiliary appliances

1. Fixed anterior bite planes, either composite bite buttons or metal eg:

bite turbo. But they can be used only if the OJ is not increase.

2. Class 2 bite corrector (some claim that it is not useful since bite

corrector has a high pull HG effect)

3. Class II inter-maxillary elastics

These are an effective means of extruding lower molars.

Mode of action

Extrusion of lower posterior teeth

They will extrude upper incisors, but the upper arch wires can be

fabricated to oppose this incisor extrusion using a gable or anchor bend.

However, even if accompanied by a millimetre of incisor extrusion, because

the molar is closer to the condylar hinge axis.

Proclination of LLS

4. Intermaxillary traction springs (Saif spring) are now commercially

available but still have a reputation for fragility

Class 2 elastic can be used in a triangular or check shape to allow

correction of OJ and extrusion of post teeth at the same time

Functional Appliances

The modes of action in reducing the OB are

1. 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

2. Through changing the direction of growth pattern


3. By some proclination of the lower labial segment may occur

Sectional archwires and auxiliary archwires

1. The “HG-tandem”

The “HG-tandem” mechanics in the maxillary arch consisted of a 2 x 4 lever

arch, cinched back and gabled 1 mm anterior to the molar band. It achieved

around 1.9 mm of true incisor intrusion (Hans 1994)

2. Anchor bend approach

The first stage of the Begg technique is a classice version of this

approach.

This approach is most useful in patient who has some growth.

Mode of action:

Proclination of ULS

Overeruption of the molars, pitted against intrusion of the LLS.

Technique:

Premolar teeth are by passed and only a loose tie is made to the

canine.

An 0.016” SS arch wire is used, with an ‘anchor bend’ anterior to the

first molar.

Light class II elastics are used to stabilise the lower molar against distal

tipping, at a cost of some extrusion of the lower molar. The lower incisors

are intruded while the class II elastics counterbalance the intrusion of the

upper incisors.

Mulligan (1980) advocated a similar approach using the edgewise

appliance. The premolars and canines are again bypassed. Isaacson et al

(1993) described it as a ‘2x4’ appliance (only two molars and four incisors

included in the appliance set-up).


3. Auxiliary levelling arch

it made from 17 × 25 mil TMA

This arch inserts into the auxiliary tube on the molar

and is tied anteriorly beneath the 0.018 ss base arch. In

essence, this augments the curve in the base arch and

results in efficient completion of the leveling by the same

mechanism as a single continuous wire. Although the auxiliary leveling arch

looks like an intrusion arch it differs in two important ways:

The presence of a continuous rather than segmented base arch and the

higher amount of force.

Leveling will occur almost totally by extrusion as long as a continuous

rather than segmented wire is in the bracket slots, while segmenting the arch

makes intrusion possible

4. 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.


Burstone recommends that the dimension of the wire be .018x.025ss

wire with a two and a half turn helix,

Alternatively, .019x.025 TMA without a helix.

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:

1. The arch wire may be tied back against the posterior segment –

however, this can put some strain on the posterior anchorage.

2. 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.

It is quite feasible to intrude asymmetrically, which requires

only adjusting the teeth that are placed in stabilizing and

intrusion segments and tying the auxiliary intrusion arch in

the area where intrusion is required. If intrusion is desired

only on one side, either a cantilevered auxiliary wire

extending from one molar or a molar-to-molar auxiliary

arch can be used. The key is tying the auxiliary arch at the point where

intrusion is desired

There is a modified Burston which used continure arch mechanics and

the auxillary intrusive wire used in the Burstone technique. This is

explained above as Auxiliary levelling arch.

5. Rickett’s (1979) utility arch


It is characterised by step-down bends

between the first molar and the lateral incisors,

It is constructed in .016” square elgiloy.

In most cases, the arch wire is placed into

the brackets with slight labial root torque to control the inclination of the

teeth as the incisors move labially while they intrude.

Success in the use of these bypass arches depends on the forces being

light.

Two weaknesses of the bypass arch systems limit the amount of true

intrusion that can be obtained:

I. 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.

II. the intrusive force against the incisors is applied anterior to the centre

of resistance – causes incisors to tip forwards as they intrude

Advantages of segemental archwires

1. A long range of action, because of the long inter-bracket span

2. More easily estimated biomechanical effects

3. Frictionless

Disadvantages of segmental mechanics

1. Complexity of fabrication

2. Poorer control of overall arch form

3. Less ‘fail-safe’ effect if the case is unsupervised for a period

4. Oral hygiene difficulties and patient discomfort if the wires impinge

on the mucosa.


5. Proclination and wagon wheel effect

Indications for segemental archwires

1. Adults

2. 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.

3. Highly positioned canines with overerupted incisors

4. Gummy smile

5. Orthodontic decompensation for AOB case treated by segemental

surgery.

Investigations comparing reverse curves of Spee AW (modified Tweed

technique) to Burstone mechanics for overbite reduction

Weiland 1996, found no significant difference bet Burstone mechanics

and modified Tweed mechanics as an end result of the DP correction. But the

Burstone mechanics cause more incisor intrusion while Tweed mechanics

cause minimal intrusion in lower and high amount of molar extrusion

Ng 2005 systematic review, The segmented arch technique in no

growing patients produced 1.5 mm maxillary incisor intrusion and 1.9 mm

mandibular incisor intrusion.



technique) to sectional arches for overbite reduction (Rickett utility

arch)

Dake & Sinclair, 1989

1. Both the Ricketts and Tweed-type arch levelling techniques were

successful in overbite correction with minimal increases in mandibular plane

angle and anterior facial height noted.

2. Mandibular incisors procline more in Ricketts group with a greater

amount of post treatment uprighting and overbite relapse than the Tweed

group.

3. Slightly more than 1 mm of mandibular incisor intrusion was noted in

the Ricketts group but no incisor intrusion was seen in the Schudy group.

Absolute Anchorage

1. Osseointegrated implants,

2. Onplants

3. Mini screws.

Degushi 2008 compared TAD with J hook for intrusion and found the

result is 3.1 and 1.3mm respectively.

Surgical treatment of the Deep Overbite

In case of an increased lower facial height the surgery may involve lower anterior

dentoalveolar setdown and BSSO advancement.

In case of an reduced lower facial height the surgery may involve 3 point landing

BSSO advancement.


Stability of OB correction depend on:

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 II angle

5. Normal lower incisor edge to centroid

6. Build up diminutive cingulum plateau

7. VH tend to continue in teenager so the use of URA with ant bite plane

as part time use is important.

8. Extraction and OB correction

Cochrane review by Millet 2007, There is no scientific evidence to

establish whether orthodontic treatment, carried out without the removal of

permanent teeth, in children with Class II division 2 malocclusion is better or

worse than orthodontic treatment involving extraction of permanent teeth or

no orthodontic treatment.

Simon and Joondeph (1973) have found that there is no correlation

between overbite stability and extraction or non-extraction treatment.

Summary of the evidences

Definition, (BSI 1983).

Prevalence Deep bite prevalence is 8% in US

Type of growth of the mandible, Nielsen et al 1991

True rotation, matrix rotation & apparent total rotation as described by Bjork

1969


Bjork’s seven features of posterior growth rotation (Bjork, 1969)

Jarabak ratio, Jarabak, 1972

Aetiology deep overbite, Naini 2006, dental update

High lower lip line, Nicole (1954)

Hyperactive Masseter muscle, Hunt 1992

Benington 1999 showed large muscle fibres in deep bite and small size

muscle fibres in AOB

However (Proffit & Fields, 1983) believe that this muscle change is a result

from malocclusion.

Increased Incisors height (Mills 1989)

Abnormal Incisor edge-centroid relationship (Houston, 1972)

Extraction of the primary canine will result in deep overbite. Stephan 1992.

Keeping in mind that in growing patient, the condyle will compensate the

extrusion and maintain the AP relationship, but in the adult the condyle not

compensate for that, however, the muscle activity adapt very well to the new

position and help in the stability (McDowell & Baker, 1991)

Proclination of lower incisor. This effect has been analysed by Eberhart et al

(1990) who, for example, stated that 5 degrees of incisor proclination would

reduce the overbite by 1 mm on average.

J hooks: (Linge and Linge 1983 show that J hook cause root re-sorption).

Degushi 2008 compared TAD with J hook for intrusion and found the result

is 3.1 and 1.3mm respectively.

Dahl appliances, originally described by Dahl in 1970.

Rectangular AW can be used too: It creates torque to move the incisor roots

lingually and Al-Qabandi et al. (1999) carried out a prospective randomised

clinical study to compare the effects of rectangular and round arch wires in

levelling the curve of Spee. They found no significant difference in

proclination between these two groups.

Study by Clifford et al (1999) indicating that with a reverse curve of Spee in


the lower archwire, the second molars in fact intrude rather than extrude.

Rickett’s (1979) utility arch


technique) to Burstone mechanics for overbite reduction, Weiland 1996,

found no significant difference bet Burstone mechanics and modified Tweed

mechanics as an end result of the DP correction. But the Bur-stone

mechanics cause more incisor intrusion while Tweed mechanics cause

minimal intrusion in lower and high amount of molar extrusion , Ng 2005

systematic review, The segmented arch technique in no growing patients

produced 1.5 mm maxillary incisor intrusion and 1.9 mm mandibular incisor

intrusion.


technique) to sectional arches for overbite reduction (Rickett utility arch) ,

Dake & Sinclair, 1989

Cochrane review by Millet 2007, There is no scientific evidence to establish

whether orthodontic treatment, carried out without the removal of permanent

teeth, in children with Class II di-vision 2 malocclusion is better or worse

than orthodontic treatment involving extraction of permanent teeth or no

orthodontic treatment.

Simon and Joondeph (1973) have found that there is no correlation between

overbite stability and extraction or non-extraction treatment.


deep overbite by almuzian

Health & Medicine

vertical overbite

aetiology deep overbite

treatment of deep ob

lower incisors

aob deep overbites

upper incisors teeth

sectional archwires

auxiliary archwires