Deep overbite / for orthodontists by Almuzian

UNIVERSITY OF GLASGOW
Orthodontic management of deep overbite
Personal note
MOHAMMED ALMUZIAN
1/1/2013
.

Mohammed Almuzian, University of Glasgow, 2013 Page 2
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...........................................................................17
In details...............................................................................................................19
Removable Appliances..........................................................................................19
Indications............................................................................................................19
Extraoral traction..................................................................................................20
Dahl appliances ....................................................................................................20
Begg Technique and Tip edge Technique,..............................................................21
Lingual appliance..................................................................................................21
Fixed appliance setting..........................................................................................21
Fixed appliance with continuous Arch Mechanics ..................................................22
Auxiliary appliances .............................................................................................24
Functional Appliances...........................................................................................24
Sectional archwires and auxiliary archwires ...........................................................25

Advantages of segemental archwires......................................................................28
Disadvantages of segmental mechanics..................................................................29
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 contactbetween 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
Nielsenet 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 softtissue 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 controlan 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 borderof
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
poorrisks 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 borderof 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 bySolow. 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 compensatoryor 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
qualifier
2f 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
Aetiologydeep overbite,
Naini 2006, dental update
 SkeletalFactors.
 Soft Tissues
 Dental factors.
 Growth Factors
 Iatrogenic Factor
I. SkeletalFactors.
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 absenceof 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 becomeworse unless the incisors have an occlusal stop.
III. Soft Tissues
a. High lowerlip 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 Massetermuscle,

 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 incisoroverbite 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 supporthas occurred.
3. Proclinationof 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. Distaltipping of posterior teeth (up righting of posterior teeth)
5. Surgery to change AP and vertical problems.
Considerationfactors 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 acceptsome 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. Faialprofile: 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 foroverbite 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 buccalsegments 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

Extraoraltraction
 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 spaceanteriorly.
 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 successfulin 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 byanchor 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 localisedintrusion bends
3. Archwires with step-downT 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 chairNiTi 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 lowerincisors
during levelling of the curve if Spee are therefore:
1. a lower incisor prescription with lingual crown torque

2. lingual crowntorque in the rectangular wire
3. intra-arch traction This requires spacein 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
correctorhas a high pull HG effect)
3. Class II inter-maxillary elastics
 These are an effective means of extruding lower molars.
Modeof action
 Extrusion of lower posterior teeth
 They will extrude upper incisors, but the upper arch wires can be
fabricated to opposethis 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 postteeth 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
Sectionalarchwires 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 classiceversion of this
approach.
 This approachis most useful in patient who has some growth.
Modeof action:
 Proclination of ULS
 Overeruption of the molars, pitted against intrusion of the LLS.
Technique:
 Premolarteeth are by passedand only a loose tie is made to the
canine.
 An 0.016” SS archwire 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 costof 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. Isaacsonetal
(1993)describedit 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 basearch 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 occuralmost 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. SegmentedBurstone 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 buccalsegments 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 TMAwithout 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, notinto 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-downbends
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 controlthe 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 weaknessesofthe bypass arch systems limit the amount of true
intrusion that can be obtained:
I. Extrusion of the first molar can occurthrough 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 segementalarchwires
1. A long range of action, becauseof the long inter-bracket span
2. More easily estimated biomechanicaleffects
3. Frictionless

Disadvantagesofsegmental mechanics
1. Complexity of fabrication
2. Poorercontrol of overall arch form
3. Less ‘fail-safe’effect if the case is unsupervised for a period
4. Oral hygiene difficulties and patient discomfortif the wires impinge
on the mucosa.
5. Proclinationand wagonwheeleffect
Indications for segementalarchwires
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 positionedcanines 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.
Investigations comparing reverse curves of Spee AW (modified Tweed
technique) to sectionalarches foroverbite reduction (Rickettutility
arch)
Dake & Sinclair, 1989
1. Both the Ricketts and Tweed-type arch levelling techniques were
successfulin 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 posttreatment 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.
Surgicaltreatment of the DeepOverbite
 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 rootre-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
 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 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.
 Investigations comparing reverse curves of Spee AW (modified Tweed
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 / for orthodontists by Almuzian

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