ORTHODONTICS

What is ortho?
It is branch of dentistry concerned with growth of face, development of dentition,
prevention & correction of occlusal anomalies.

Prevalence of malocclusion:
60% crowding →20% CII/1→10%CII/2→3% CIII

Why do orthodontics?
1. Correction of malocclusion for aesthetic purposes.
2. Better functioning occlusion
3. ↓ risk of trauma (as in incompetent lips)
4. Prevent compromised periodontal support labially (as in crowding of lower incisors).
5. Better self-esteem &psychological self being.

Who should do orthodontics?

✓ All dentists should be concerned with growth, development & early detection of
anomalies.
✓ Most orthodontic ttt in Europe & UK now is carried out by trained specialist
orthodontic practitioners.
✓ The consultant is a source of advice & referral point for more complex problems.

When should we do orthodontics?

Most ortho. ttt is not started until the early permanent dentition. Why?
1. When canines & PM are erupted.
2. At this age, the response to ortho forces is more rapid.
3. Appliances are better tolerated.
4. Growth can be utilized to help effect on sagittal & vertical changes.

Drawbacks of orthodontic ttt (relatively)?

1. Loss of periodontal support.
2. Decalcification.
3. About 1-2 mm of root resorption is associated with fixed ortho. (Short blunt roots).
4. Soft tissue abrasions & oral ulceration.
5. Pulpal damage especially with overactivation & previous trauma.
6. Cost & time.
 Etiology of malocclusion
➢ Skeletal problems:
1. Genetic (anomalies, syndromes, endocrinal)
2. Environmental
3. Soft issue & functional alterations.
4. Birth trauma
5. Rheumatoid arthritis
➢ Crowding, due to:
1. Early loss of deciduous teeth by trauma or caries.
2. Softer &less abrasive diet →↓soft tissue pressure+ ↓jaw function over
developing dentition.
3. Para functional habits (mouth breathing, digit sucking, chin trapping…)

Classification of malocclusion
I. Skeletal classification
II. Classification for diagnosis
• Angle`s classification (1st molar relationship)
• British standards institute classification (incisor relationship)
• Canine relationship
III. IOTN (classification according to ttt needs)

I. Skeletal classification
1) Skeletal Class I: normal relationship between maxillary &
mandibular skeletal base.
Mandible is 2-4 mm behind max.
2) Skeletal Class II: protruded maxillary skeletal base &/or
retruded mandibular skeletal base.
Mand is >4mm behind max.
3) Skeletal Class III: retruded maxillary skeletal base &/or
protruded mandibular skeletal base.
Mand is < 2 mm behind max.
 II. Classification for diagnosis

Angle`s classification
(Molar relationship)
1) Class I (neutrocclusion):
The MB cusp of the upper 1st perm. Molar occludes
in a buccal groove of the lower 1st perm molar.
2) Class II (post normal occlusion or distocclusion):
The MB cusp of the upper 1st perm. Molar occludes
anterior to the buccal groove of the lower 1st perm
molar.
3) Class III (prenormal or mesiocclusion):
The MB cusp of the upper 1st perm. Molar occludes
posterior to the
buccal groove of the lower 1st perm molar.

British standards institute classification

(Incisor relationship)
1) Class I: the lower incisor edges occlude with or lie immediately
below the cingulum plateau of the upper central incisor.
2) Class II: the lower incisor edges lie posterior to the cingulum plateau
of the upper incisor.
✓ Division 1 →proclined upper central incisors = increased
overjet = incompetent lips.
✓ Division 2 → retroclined upper central incisors = the overjet
is usually minimal = competent lips
3) Class III: the lower incisor edges lie anterior to the cingulum plateau
of upper incisors. The overjet is reduced or reversed.

Canine relationship
1) Class I: the mesial slope of the upper canine cusp lies in a normal relation to the distal slope of the
lower canine cusp.
2) Class II: the mesial slope of the upper canine lies in an anterior relation to the distal slope of the
lower canine cusp.
3) Class III: the mesial slope of the upper canine cusp lies in a posterior relation to the distal slope of
the lower canine cusp.
 III. Classification according to ttt needs
The Index of Orthodontic Treatment Needs
IOTN
- The IOTN was developed to standardize an individual patient’s needs for orthodontic ttt.
- It consists of 2 components:
✓ The dental health component, it has 5 categories of ttt need, ranging from little ned to very
great need. Pt`s grade is determined by the single worst feature of their malocclusion.
MOCDO ruler is helpful to determine Missing teeth, Overjet, Crossbite, Displacement,
Overbite.

✓ The aesthetic component, it is based on a series of 10 photographs of the labial aspects of

different class I or class II malocclusions which are ranking according to their attractiveness.

A. Dental health component (DHC):

Examine each pt. using MOCDO scale for 5 specific conditions and if one is found, a Definite Need for
Treatment is recorded.
M = missing teeth
O = overjet
C = cross bites
D = displacement of contact points
O = overbite

Grade 1 ( No need ) : extremely minor malocclusions including displacements < 1 mm.

Grade 2 Grade 3 Grade 4 Grade 5
Little need Moderate Great Very great
a →overjet 3.5 -6 mm& competent 3.5 -6 mm& 6-9mm >9 mm
lips incompetent lips
b→ reverse overjet <1 mm <3.5mm >3.5mm with no speech
or masticatory
difficulties.
c→ crossbite < 1mm <2mm >2mm

d→displacement of <2mm <4mm > 4mm

teeth
e→ openbite ant. or post. >2mm ant. or post. <4mm > 4mm
f→ overbite ↑↑ Ob 3.5 mm or more Complete Ob Complete Ob with
without gingival contact. without gingival gingival or palatal
trauma. trauma.
g→ prenormal or
postnormal occlusion
with no other anomalies.
 Grade 4 Grade 5
Great Very great

h → hypodontia less extensive hypodontia extensive hypodontia with restorative implications.

m→ reverse overjet <3.5mm >3.5mm

with masticatory
&speech difficulties.
l→ lingual crossbite with no functional occlusion.
posteriorly Contacts in 1 or both segments.
t→ partially erupted, tipped or
impacted tooth.
x→ supplemental teeth.
i→ impeded eruption of teeth ( with exception of 3rd
molar) due to:
1. Crowding
2. Displacement
3. Supernumerary
4. Retained decide.
p→ cleft lip & palate.
s→ submerged decidous tooth

B. Aesthetic component

Ask the pt. to close on their back teeth, retract lips, then grade the dental attractiveness of the anterior
teeth.
Score 1 or 2 → no need for ttt
Score 3 or 4 → slight need for ttt
Score 5, 6, 7 → moderate need for ttt (border line)
Score 8, 9, 10 → definite need for ttt.

An average score can be taken from the two components, but dental health alone is more widely used.
 Cephalometric
- It is the interpretation of lateral skull radiograph.
- They are taken in cephalostat to standardize position & magnification.
- It is not essential for
1. ortho. ttt especially with skeletal discrepancy.
2. where the incisor position is to be changed significantly in anteroposterior
plane.
- It includes points, planes & angles.

Points:
1. S (Sella): midpoint of sella turcica.
2. N (nasion): most anterior point of fronto-nasal suture.
3. Or (orbitale): most inferior anterior point on margin of orbit.
4. Po (porion): uppermost outermost point on bony external auditory meatus.
5. ANS: anterior nasal spine
6. PNS: posterior nasal spine
7. Go (gonion): most posterior inferior point on angle o mandible.
8. Me (menton): lowermost point on the mandibular symphysis.
9. Pog (pogonion): the most anterior point on mandibular symphysis
10.Gn (gnathion): the midpoint between Me & Pog.
11.A point: position of the deepest concavity on anterior profile of maxilla.
12.B point: position of the deepest concavity on anterior profile of mandibular
symphysis.

Planes:
1. SN plane: S-N points
2. Frankfort plane: Po-Or points, represents base of skull.
3. Maxillary plane: PNS –ANS
4. Mandibular plane: Go-Me.
5. Functional occlusal plane (FOP): along functional cusp tips of molars & PM.

Angles (cephalometric analysis):

• Skeletal pattern (Anteroposterior relationship)
• Incisor angulation (Dental relationship)
• Facial proportions (Vertical relationship)

Skeletal pattern (Anteroposterior relationship)

1. SNA = 81° (+-3)
2. SNB = 79° (+-3)
3. ANB = 3 (+-2)
✓ ANB = 2-4 ° → Class I skeletal relationship.
✓ ANB <2 ° → Class III skeletal relationship
✓ ANB > 4 ° → Class II skeletal relationship
ANB angle varies with the relative prominence of nasion & lower face.
If SNA significantly ↑ or ↓, this could be due to position of nasion, in which case an additional
analysis should be used, e.g., Wits analysis.

Wits analysis
- Used to assess anteroposterior relationship skeletal pattern.
- Drop a perpendicular line from A point to FOP = AO
- Drop a perpendicular line from B point to FOP = BO
- Measure the distance from AO to BO
- In class I:
✓ Males: BO = AO + 1mm (+-1.9 mm)
✓ Females: BO = AO (+- 1.7)

Incisor angulation (Dental relationship)

1. Upper central incisor & maxillary plane (1/Max) = 109° (+-6)
2. Lower central incisor & mandibular plane (1/Mand) = 93° (+-6)
3. Inter incisal angle (II Δ) = 133° (+-10)

Facial proportions (Vertical relationship)

1. Maxillary mandibular plane angle (MMPA)
✓ Normal = 27° (+- 4)
✓ Increased LFH > 31°
✓ Decreased LFH < 23°
2. Frankfort mandibular plane angle (FMPA)
✓ Normal = 28° (+-4)
✓ Increased LFH > 32°
✓ Decreased LFH < 24°

Space analysis
- Space required for ttt is measure on the casts.
- Space is required to correct the following:
• Crowding
• Incisor anteroposterior change (usually obtaining a normal overjet of 2 mm)
• Levelling of occlusal curves
• Arch contraction (expansion will create space) as in v shaped arches.
• Correction of upper incisor angulation (mesiodistal tip)
• Correction of upper incisor inclination (torque)

- Space required can be created by:

1. Extractions 6. A combination of any methods
2. Distal movement of molars
3. Enamel stripping
4. Expansion
5. Proclination of incisors
 1. Extractions:
Incisors • Lower incisor → rarely, may be in c. III.
• Upper central → never
• Upper lateral → may be the choice if (abnormally formed, absent in other side, palatally excluded &
canines with centrals are in good contact)
Canines Cornerstone of the arch, can be extracted only if:
Ectopic (displaced) & 1st PM with laterals are in good contact.
1st premolars • These are often the teeth of choice to be extracted when the space requirement is moderate to
severe.
• extraction of a first premolar in either arch usually gives the best chance of spontaneous alignment.
2nd premolars • Mild to moderate space requirement (3–8 mm space required)
• Space closure by forward movement of the molars, rather than retraction of the labial segments is
indicated
• Severe displacement, hypoplasia, caries of the second premolar
• Absent in one quadrant
1st molars If poorly prognosed 1st molar with consideration of timing.
2nd molars • To facilitate distal movement of upper buccal segments
• Relief of mild lower premolar crowding
• Provision of additional space for the third permanent molars, thus avoiding the likelihood of their
impaction
3rd molars If there is a pathology (but not to prevent lower labial segment crowding)

2. Distalization of upper molars:

- Space created by distalization is much less than space created by extractions.
- Distal movement of the lower first molar is very difficult and in reality, the best that can be achieved is up
righting of this tooth.

Can be achieved by:

1. Head gear (extraoral traction)
2. TADs (temporary anchorage devices)

3. Interproximal stripping
- 0.25 mm of each proximal surface of enamel of anterior teeth.
- 0.25x2 x4 anterior teeth = 2 mm space in anterior teeth
- 3-6 mm of space creation of buccal segment.
- After stripping, fluoridation of the tooth to prevent caries.
- Stripping is done using abrasive strip with acid & pumice to provide a smoother surface.

4. Expansion
- Space can be created by expanding the upper arch laterally.
- approximately 0.5 mm is created for every 1 mm of posterior arch expansion.
- Expansion should ideally only be undertaken when there is a crossbite.
- Expansion without a crossbite may increase the risk of instability and the risk of perforation of the buccal
plate.

5. Proclination of incisors
- Space can be created by proclining incisors, but this will be dictated by the aims of the treatment.
- Each 1 mm of incisor advancement creates approximately 2 mm of space within the dental arch.

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 Space maintenance

The best space maintenance is a tooth – particularly as this will preserve alveolar bone.
Types of space maintainers:
Unilateral fixed SM:
1- band & loop / crown & loop
2- distal shoe
Bilateral fixed SM:
1- lower lingual arch
2- transpalatal arch
3- Nance appliance
Anterior SM:
1- Aesthetic anterior SM may be removable or fixed.

Function of SM:
1- Maintain space.
2- Prevent unwanted movement of neighbouring teeth to the extraction site.
3- Provide masticatory, speech & aesthetic function.
4- Prevent overeruption of opposing.

Planned extraction of deciduous teeth

1- Serial extraction
- Sequence → CD4
- Extract c at 8.5-9.5 y, extract D 1 year later, extract 4 as 3 is erupting.
- Indicated for → class 1 malocclusion with moderate crowding & all perm teeth in good
position.
- to allow crowded incisor segments to align spontaneously during the mixed dentition by
shifting labial segment crowding to the buccal segments where it could be dealt with by first
premolar extractions.
- Not used any more due to psychological trauma by multiple extractions.

2- Extraction of deciduous canines

Indicated
• In a crowded upper arch, the erupting lateral incisors may be forced palatally.
• In a crowded lower labial segment one incisor may be pushed through the labial plate of
bone resulting a compromised labial periodontal attachment.
• Extraction of the lower deciduous canines in a Class III malocclusion can be advantageous.
• To provide space for appliance therapy in the upper arch, for example correction of an
instanding lateral incisor, or to facilitate eruption of an incisor prevented from erupting.
• To improve the position of a displaced permanent canine

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 Removable appliances
Mode of action:
Removable appliances are concerned with the following movements.
• Tipping movements –
• Movements of blocks of teeth – because removable appliances are connected by a baseplate, they are
more efficient at moving blocks of teeth than fixed appliances.
• Influencing the eruption of opposing teeth – this can be achieved either by use of:
(1) a flat anterior bite-plane, which frees the occlusion of the lower incisors allowing their eruption.
This is useful in overbite reduction.
(2) buccal capping, which frees the contact between the buccal segment teeth. This may also be of
value when intrusion of the buccal segment.

Advantages of Rem. Ortho. appliances Disadv. Of Rem. Ortho. appliances

1- Can be removed for tooth-brushing. 1- Appliance can be left out.
2- Palatal coverage increases anchorage. 2- Only tilting movements possible
3- Easy to adjust. 3- Good technician required.
4- Less risk of iatrogenic damage (e.g., root 4- Affect speech.
resorption) than with fixed appliances 5- Intermaxillary traction not practicable
5- Acrylic can be thickened to form flat anterior 6- Lower removable appliances are difficult to
bite-plane or buccal capping. tolerate.
6- Useful as passive retainer or space maintainer 7- Inefficient for multiple individual tooth
7- Can be used to transmit forces to blocks of movements
teeth

Steps in designing removable ortho appliance:

• Active component(s) • Retentive component • Anchorage • Baseplate

Active components:
1- Springs
2- Screws
3- Elastics
4- Active labial bow
Palatal movement Buccal / lingual movement
(For proclined teeth) (For retroclined teeth)
Incisors Active labial bow 0.7 mm Double cantilever spring 0.6-0.7mm
Z spring 0.5 mm
Canine Canine retractor 0.7 mm Palatal finger spring 0.5 mm
Long labial bow 0.7 mm
Upper 4 ,5 ,6 Buccal retractor 0.5mm If single tooth: T spring 0.5mm
Long labial bow 0.7 mm If > 1 tooth: screw appliance
Distalization of Palatal finger spring 0.6 mm
upper 6
- Z spring can be used for proclination of 1-2 anterior teeth.
- T spring can be used for proclination of 1-2 premolars.
- Finger spring is used for distalization of one tooth.

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Retentive components:
1- Adam`s clasp
2- Retentive Labial bows
3- Others (southend clasp, plint clasp, bell ended clasps)

Adam`s clasp
- The most popular retentive clasp.
- This crib was designed to engage the undercuts present on a fully erupted first permanent molar at the
junctions of the mesial and distal surfaces with the buccal aspect of the tooth.
- be used for retention on premolars, canines, central incisors, and deciduous molars.
- Modifications to Adam`s clasp (Extra-oral traction tubes, labial bows, buccal spring, hooks, coils &
double clasps).

Base plate
- The other individual components of a removable appliance are connected by means of an acrylic
baseplate, which can be a passive or active component of the appliance.
- It may be made of self-cure acrylic resin or heat cure acrylic resin.
Modifications:
1- Anterior bite plane: used for
a) Correction of overbite by allowing eruption of lower buccal segment.
b) Elimination of occlusal interferences by allowing tooth movement to occur.
2- Buccal capping: used for
occlusal interferences need to be eliminated to allow tooth movement to be accomplished and
reduction of the overbite is undesirable (anterior crossbite in single tooth)

Patient instructions:
the pt. should be instructed for full time wear, how to insert & remove, oral hygiene maintenance & remove
it during eating hard & sticky food.

Monitoring progress:
1- Evidence of wear & tear.
2- No lisping (ask the pt. to count 65-70 with & without the appliance)
3- Marks around the gingival margins & palate
4- No frequent breakage

Common problems during ttt by removable appliance:

1- Slow rate of tooth movement (normally it is 1mm /mon for children & little less for adults)
2- Frequent breakage.
3- Anchorage loss
4- Palatal inflammation
- Due to mixed fungal & bacterial infection.
- Entrapment of the gingivae between the acrylic and the tooth/ teeth being moved.

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 Functional appliances
Definition: Functional appliances utilize, eliminate, or guide the forces of muscle function, tooth eruption
and growth to correct a malocclusion.

- There are many different types of functional appliances, but most work by the principle of posturing
the mandible forwards in growing patients.
- They are most effective at changing the anteroposterior occlusion between the upper and lower
arches, usually in patients with a mild to moderate Class II skeletal discrepancy.
- They are not effective for correction of teeth irregularities & arch alignment, so they are followed
with a phase of fixed appliance treatment.
- It has been suggested that treatment should, if possible, coincide with the pubertal growth spurt
(Predicted by maturation changes seen on the cervical vertebrae visible on lateral skull radiographs)
- Functional appliance ttt starts in early or late mixed dentition.
- They are either tissue borne, or tooth borne, removable or fixed.

Types of malocclusions treated with functional appliance:

1- Ttt of class II div. 1 malocclusion
2- Ttt of class II div 2 malocclusion
3- Ttt of class III (but it is better& more simply treated with orthodontic camouflage with fixed
orthodontic appliances)

Types of functional appliances:

1- Twin block appliance
2- Herbst appliance
3- Medium opening activator (MOA)
4- Bionator
5- Frankle appliance
Description Advantages Disadvantages
Twin block - is the most popular - Well tolerated by the - the residual posterior lateral
appliance functional appliance in pt. open bites at the end of the
the UK. - The appliance can be functional phase.
- Two parts upper & lower worn full time, so - Bulky appliance
fitting together using rapid correction is - Not suitable for all cases.
posterior bite blocks with expected.
interlocking bite planes. - Reactivation is
The blocks are 5 mm feasible if more
height. mandibular
advancement is
required.
- Successful in reducing
O.J in class II.
Herbst -the only fixed functional - less bulky than twin - increased breakage tendency.
appliance orthodontic appliance. block - Higher cost.
-the most popular - patients find it easier to - pt. cannot do lateral movement.
functional appliance in eat and talk with it in
US. place.
- There is a section - Successful in reducing
attached to the upper O.J in class II.
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 buccal segment teeth and
a section attached to the
lower buccal segment
teeth. These sections are
joined by a rigid arm that
postures the mandible
forwards

Description Advantages
Medium -is a one-piece functional appliance, with - one piece appliance, so more tolerated.
opening minimal acrylic to improve patient comfort
activator - The lower acrylic extends lingual to the - No molar capping, allow reduction of deep
(MOA) lower labial segment only, and the upper and bite.
lower parts are joined by two rigid acrylic
posts, leaving a breathing hole anteriorly.
Bionator - It was originally designed to modify -A buccal extension of the labial bow holds the
tongue behaviour cheeks out of contact with the buccal segment
teeth, allowing some arch expansion.
-lack of acrylic in the palate makes it easy to wear
Frankle - is the only completely tissue-borne -It has buccal shields to hold the cheeks away from
appliance. the teeth and stretch the periosteum
- There are different versions designed to
treat different types of malocclusions. Disadv:
- it postures the mandible forwards 1- Difficult to wear.
2- Difficult to repair.
3- Expensive
4- Not frequently used.

Effects of functional appliances (mode of action):

Skeletal changes 25 %:
1- Promotes postural mandibular growth by 1-2 mm/ mon., if no changes after 3 mon, switch to fixed
ortho ttt.
2- Promotes forward position of glenoid fossa.
3- ↑ lower anterior facial height LAFH

Dentoalveolar changes 75%:

1- Tipping of upper anteriors palatally (retroclination)
2- Tipping of lower anteriors labially (proclination)
3- Distal movement & intrusion for upper molars.
4- Mesial movement & extrusion of lower molars.

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 Anchorage planning
Definition: Anchorage is defined as the resistance to unwanted tooth movement.
Aim of anchorage:
- maximize desired tooth movement and minimize unwanted tooth movement.
Classification of anchorage:
• Intraoral anchorage
1. Increasing number of teeth incorporated in anchorage.
2. Transpalatal & lingual arches.
3. Intermaxillary anchorage (elastic traction)
4. Removable & functional appliances.
5. TADs (temporary anchorage devices), 3 types: miniplates, miniscrews, osseointegration.

• Extraoral anchorage (head gear)

Types of head gear:
- Extraoral traction: applies a distal force to the posterior teeth to achieve tooth movement usually in
a distal direction. Traction is also used to attempt to restrict the growth of the maxilla forwards and
downwards.
- Extraoral anchorage: holds the posterior teeth in position, preventing unwanted mesial movement of
the anchorage unit.

There are three directions of pull that can be achieved with headgear:
1- High or occipital-pull headgear which helps to control the vertical as well as anteroposterior
anchorage and is typically used in cases with increased vertical proportions.
2- Straight or combi-pull headgear which controls the anteroposterior and is typically used in cases with
average vertical proportions.
3- Low or cervical-pull headgear which aid in the control of anteroposterior anchorage but is also used
to increase the vertical dimension by having an extrusive effect on the molars in cases of reduced
vertical proportions.

Components of headgear:
1- Facebow
2- Headcap or strap

Headgear safety:
Injuries associated with headgear have been reported in the past. Most notably these include serious ocular
injuries which reportedly resulted in blindness. This is because of the ends of the face-bow coming out of
the mouth and causing direct trauma to the eyes.
The British Orthodontic Society recommends that at least two safety features are incorporated into the
headgear:
1- snap-away safety release mechanism.
2- rigid neck strap (as Masel strap which is the simplest)
3- locking face-bow
4- safety facebow
Reverse headgear = Face mask
it has 2 main uses (mainly for class III malocclusion):
1- Tooth movement: moving the posterior maxillary teeth mesially.
2- Skeletal changes: advancement of the maxilla can be achieved in patients, where a facemask is fitted
and worn a minimum of 14 hours per day.

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 Retention
- One of the commonest risks of orthodontic treatment is relapse. Orthodontists use orthodontic
retention to try and minimize this relapse.
- Relapse = return after correction = change from the final tooth position at the end of treatment

Etiology of relapse:
• Gingival and periodontal factors (Until the periodontium adapts to the new position, there is a
tendency for the stretched periodontal fibers to pull the tooth back to its original position. Different
parts of the periodontal ligament complex remodel at different rates (from 3-8 mons)
• Occlusal factors (better interdigitation = better retention)
• Soft tissues factors (place the teeth in neutral zone between tongue & cheek)
• Growth factors (late growth changes as lower incisor crowding)
The orthodontist can control periodontal factors & occlusal factors but cannot control soft tissue & growth
changes. that is why there is unpredictable risk for relapse throughout life.
(70% of pt. may need retreatment due to relapse) so written informed consent is a must.

Types of retainers:
Removable retainers Fixed (bonded) retainers
Advantages: 1- Oral hygiene maintenance 1- patients do not need to remember to wear
2- part time wear them.
3- responsibility of the pt. not orthodontist. 2- they are useful when the result is very
unstable
Instructions for removable ret: Cases of fixed ret.:
1- Vacuum-formed retainers only need 1- closure of spaced dentition (including median
to be worn at night, every night. diastema)
2- never to drink with the vacuum- 2- severely rotated teeth
formed retainer in situ, particularly 3- movement of the lower labial segment, either
cariogenic drinks. excessive proclination or retroclination, or a
3- Maintain good oral hygiene. significant change in the intercanine width
4- A spare retainer is provided if one is 4- where an overjet has been reduced, but the
lost. lips are still incompetent.
5- Clean the vacuum retainer by 5- combined periodontal and orthodontic cases,
toothbrush & water but not where reduced periodontal support makes
toothpaste. relapse more likely.
6- Remove during meals.
7- Keep retainer safe in a protective
box.
Most 1- Hawley retainer they are usually attached to the palatal aspect of the
common 2- Vacuum formed. upper or lower labial segment, using normal acid-etch
types: 3- The positioner composite bonding.

Adjunctive techniques used to reduce relapse:

• Precision = circumferential supracrestal fiberotomy to reduce rotational relapse.
• Interdental stripping = reproximation for flattening of interproximal contact to increase stability.

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 Fixed appliances
Advantages of fixed ortho. Appliances Disadvantages of fixed ortho. App.
• Correction of mild to moderate skeletal discrepancies: as fixed • They are not as effective at moving blocks of
appliances can be used to achieve bodily movement. teeth as are removable or functional appliances.
• Intrusion/extrusion of teeth: vertical movement of individual • maintain a high level of oral hygiene, dietary
teeth, or tooth segments, requires some form of attachment advice, F mouth paste & mouth rinse.
onto the tooth surface on which the force can act. • avoid hard or sticky foods and restrict the
• Correction of rotations. consumption of sugar containing foodstuff s
• Overbite reduction by intrusion of incisors. between meals.
• Multiple tooth movements required in one arch. • co-operate fully with wearing headgear or elastic
• Active closure of extraction spaces, or spaces due to traction, if required.
hypodontia: fixed appliances can be used to achieve bodily space • attend regularly to have the appliance adjusted.
closure and ensure a good contact point between the teeth.

Components of fixed appliances:

1- Bands
2- Bonds (brackets) metallic or ceramic
3- Orthodontic adhesives (GIC, composite, compomer, self-etching primer)
4- Orthodontic auxiliaries (elastic bands, wire ligature springs, palatal & lingual arches)
5- Arch wire

Aesthetic orthodontic appliances:

1- Aesthetic orthodontic brackets and wires
2- Clear orthodontic aligners: the Invisalign ® concept
3- Lingual orthodontics

Disadvantages of ceramic brackets:

• Attachment to bonding adhesive (chemical bond too strong, mechanical interlock difficult)
• Frictional resistance is high – limiting sliding mechanics
• Brittle
• Can cause tooth wear if opposing tooth in contact
• Problems with debonding

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 Orthognathic surgery
Which cases are indicated for surgery?
• Severe Class II skeletal malocclusions
• Severe Class III skeletal malocclusions
• Severe vertical disproportions leading to anterior open bite or a severely increased overbite
• Skeletal asymmetries

Common surgical procedures:

Maxillary techniques Mandibular techniques

Lefort I Sagittal split osteotomy
Lefort II Vertical subsigmoid osteotomy
Lefort III Body osteotomy
Surgical Assisted Rapid Palatal Expansion (SARPE) Genioplasty

Bimaxillary surgery
- Many patients require surgery to both jaws to correct the underlying skeletal discrepancy.

Distraction osteogenesis
- This is a technique that involves osteotomy cuts followed by a slow mechanical separation of the bone fragments
with an expandable device.
- It has been found to be useful in the treatment of patients with severe jaw deficiencies, particularly those
associated with craniofacial syndromes.
- Extraoral or intraoral fixation devices are needed for a period of time.

- MKA| 17