Growth modification and head gears
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Transcript of Growth modification and head gears
Dr. Rashid Mahmood
Discrepancies
Skeletal
Dental
Soft-tissues
Three dimensions
↔Transverse
→Sagittal
↕Vertical
Transverse Discrepancies
Vertical Discrepancies
Sagittal Discrepancies
Sagittal Discrepancies
Sagittal Discrepancies
In Orthodontics
Definition: Removable or fixed orthodontic appliances which use
forces generated by the stretching of muscles, fascia and
/ or Peridontium to alter skeletal and dental
relationships.
stretching of muscles, fascia and
/ or Peridontium
Form follows function
Form follows function
“If compensatory, adaptive lip and tongue function could exacerbate excessive over-jet in class II-type malocclusions and if abnormal
swallowing and prolonged finger-sucking habits could create anterior
open-bite and narrow maxillary arches, could not the same muscles be used to correct these and other problem????”
Background Functional appliances are conceptually based on
Moss’ functional matrix theory
Functional matrix theory proposes that functional matrices, tissues like muscles and glands influence skeletal units such as jaw bones and ultimately control their growth
The appliances used to improve functional relationship of dento-facial structures by eliminating unfavorable developmental factors and
improving the neuromuscular environment enveloping the developing occlusion
Function
Muscular Action
Effect on dento-alveolar development
What they do…..? Alter the neuromuscular environment of oro-facial region to improve
occlusal development and/or craniofacial skeletal growth
Utilize muscle forces to effect bony and dental changes
Disarticulate the teeth
Encourage new mandibular position
Require a tight lip seal during swallowing
Selectively alter the eruptive path of teeth
When???
When??? Functional appliance treatment should be started before
the pubertal growth spurt
This is the time when the mandible may exhibit increased growth which may be influenced
Duration---------------------------10-12 hours a day
These appliances should be worn at night-time as this is when growth takes place
INDICATIONS
1. Growing ages (Mixed dentition and/or early permanent dentition)2. Skeletal Considerations (Sagital correction of class II &III)
Skeletal Class II with Short mandiblea) Class II division 1b) Class II division 2 (Convert div 2 to div 1)
1. Vertical Considerations
a) Normal to low angle cases2. Dental Considerations
a) Local irregularity & rotation of incisors especially upper incisorsb) Crowding or dental compensation (Pre-functional Orthodontics
require3. Open bite/ deep bite correction
4. Cross bite correction
5. To correct mal-forming dysfunction
CONTRAINDICATIONS1. Children with neuromuscular disorders
a. Poliomyelitis
b. Cerebral palsy
2. Compliance
3. Hyperdivegent faces
4. Unfavorable growth
5. Protruded lower incisors
6. Severe crowding
7. Age
Treatment Principles Force Application: Compressive stress and strain act
on the structures involved resulting in primary alteration in form and secondary adaptation in function e.g all removable appliances
Force Elimination: Abnormal and destructive environmental influences are eliminated to allow optimum development
like lip bumpers and frankel buccal sheilds
Mode of Action
Functional Appliances influence facial skeleton through condylar and sutural areas.
Goal is to
Use the functional stimulus of oro-facial muscles , channeling this stimulus to the jaws, condyles and teeth to bring the change.
Purely functional and intermittent forces
Limitations Adult Age(Ineffective in adults)
High Angle Cases(Increases vertical height of patient)
Compliance
Precise detailing of tooth position not possible
Crowding (Cases with ALD are difficult to manage)
Precise correction of Incisor inclination not possible
Increased lower incisor inclination (They tend to increase lower incisor
inclination & thus proper Sagital correction may not be possible if not properly
managed)
Functional appliances if used properly & at right time then
they help in improving the profile and eliminating the need
for Orthognathic Surgery
TYPES
Active
Passive
Active appliances reposition the mandible so that the condyle is forced out of the glenoid fossa and this in turn is thought to stimulate the posterior/superior growth of the condyle.
Passive appliances act by repositioning the musculature associated with the mandible so that the jaw bone itself responds by growing to the new equilibrium position
FUNCTIONAL
APPLIANCES
SIMPLE
FUNCTIONAL
APPLIANCES
REMOVABLE
FUNCTIONAL
APPLIANCES
FIXED
FUNCTIONAL
APPLIANCES
SIMPLE FUNCTIONAL APPLIANCES
Force elimination appliances e.gOral shields,Tongue cribs ,Habit breakers, Lip bumpers
JAW ORTHOPEDICS APPLIANCES
REMOVABLE FUNCTIONAL APPLIANCES FIXED FUNCTIONAL APPLIANCES
TYPES
Tooth Borne
Tissue Borne
Lip bumper Can be used for both mand and
maxilla Uses the muscular force from
upper or lower lip to provide distal force specially to molars
In lower arch headgear is less acceptable so lip bumper is useful
Remove soft tissues forces from labial aspect
Result increased lower incisor inclination by influence of tongueThis can be reduced by placing it as low as possible in labial sulcusso that upper part of lip is in contact with teeth
Simple functional appliances
Simple functional appliances
Oral screens Forerunner of functional
regulator
Consists of vestibular shieldswhich holds the lip away from allteeth except upper incisors b/cpressure from lips is transferredto U I and acts to move thempalatally
Can be used in mixed dentitionand aids patient with digitsucking
Jaw Orthopedic Functional
Appliances
Removable Functional Appliances
TOOTH BORN MONOBLOCK ACTIVATORS BIONATORS TWIN BLOCKS MAGNETIC APPLIANCE
TISSUE BORN FRANKEL FUNCTIONAL APPLIANCE
Fixed Functional Appliances
Flexible Fixed Functional Appliances (FFFA) Rigid Fixed Functional Appliances (RFFA) Hybrid Appliance Fixed version of RFA (fixed twin block , dynamix appliance) Elastics
TYPES MYOTONIC
Depend upon displacement of mandible in AP and vertical plane. e.g Activators
MYODYNAMIC
Not only translate the mandible AP & vertically but also attempt to utilize and translate muscular movements e.gBimler appliance
Passive functional appliances Frankel
Active functional appliances Removable active functional appliances
Bionator
Active functional appliances Removable active functional appliances
activator
Active functional appliances Removable active functional appliances
Twin-block appliance
Active functional appliances Fixed active functional appliances
Herbst
Andresen Activator Mono-block
As upper and lower plates appear joined together
Activator
Norwegian appliance
Viggo Andersen
Modified Andresen–Häupl-type activator
Class II cases Div I
For better control of lower incisor inclination,
the lower incisors are covered with acrylic,
which is relieved on the lingual surface
Correct overjet, overbite and molar relationship
during active growth
Labial bow to prevent incisors proclination
Maximum extension of lower lingual flanges in order to redistribute the force on mucoperiostium of mandible
Coffin spring instead of palatal plate
Canine loops ----- screening loops of bionator and buccal shields of FR.
Difficulty in speech
Needs removal during eating
Arch expansion cannot be carried out simultaneously
Limitations
Labial view of the Andresen appliance. The picture shows labial Bow in 0.8mm S.S wire with tubing and lower incisal capping.
Andresen
Models removed
Andresen
Lingual or palatal view
Andresen
Buccal Views
Andresen
FRANKEL APPLIANCE
FRANKEL CORRECTOR
FUNCTIONAL REGULATOR
Dr. Rolf Frankel
FRANKEL APPLIANCE
FRANKEL CORRECTOR
FUNCTIONAL REGULATOR
Dr. Rolf Frankel
Passive functional appliance
Essentially tissue borne
Appliance of choice in class II due to mandibular retrusion.
Used in early mix dentition.
Has direct effect on neuromuscular system.
Causes anterior advancement of mandible and increase in LAFH.
Expands dental arches.
FUNCTIONAL REGULATOR
Oral vestibule is used as operational basis for the treatment of dentoalveolar discrepancies.
It combines the principles of Anderson’s appliance and oral screen.
Mode of action depends upon the relieving and lifting the pressure on teeth from lips and cheeks, so that the jaws can be allowed to grow and the teeth can be guided to move into new more favorable position.
Frankel Appliance
The wire assembly anchors the appliance on the maxillary arch at the mesial embrasure of the of first molar.
Frankel ApplianceRolf Frankel
A cross palatal stabilizing wire on the maxillary arch.
FUNCTIONAL REGULATOR
FR I
a. Class I
b. Class II div 1 <5mm
c. Class II div 1 >7mm
FR II Class II div 2
FR III Class III
FR IV Open bite & mild bimax
FUNCTIONAL REGULATOR
FR I
a. Class I
It is mainly used to treat cases of Class Imalocclusion with minor to moderate crowdingor arrested development of dental bases.
It can also be used in class I malocclusion withdeep bite.
FR I Appliance
Labial view
The components include:Upper
• Palatal wire 6 / 6 in 0.9mm S.S wire.• Canine wires 3 / 3 in 0.9mm S.S
wire.• Labial Bow 2 / 2 in 0.9mm S.S wire.
Lower • Lip Pads and Joining wires in 0.9mm
S.S wire.• Hanger wires 5 / 5 in 0.9mm S.S
wire.• Lingual Pusher Springs 3 / 3 in
0.7mm S.S wire.
FR I Appliance
Buccal view of the Frankel appliance.
FR I Appliance
Frankel appliance - lingual / palatal view.
FR I Appliance
Frankel appliance with upper model removed.
FR I Appliance
Frankel appliance with lower model removed.
FUNCTIONAL REGULATOR
FR I
b. Class II div 1 where over-jet is <5mm
c. Class II div 1 where the over-jet is >7mm
FUNCTIONAL REGULATOR
FR II Class II div 2
Prior to the functional therapy the incisor need to be aligned
FR II Appliance
Buccal Shields
Labial Pads
Labial Bow
Canine Clasps
Occlusal Rests
Palatal Arch
1. Flexible Appliance
2. The lingual and labial segments in lower portion encourage holding the mandible in a postured
position to alter the lip behavior.
3. By retraining the facial muscles & muscles of mastication to occupy new position.
4. The maxilla & mandible will be influenced to grow into corrected position.
5. Stretching of periosteum, osteoblastic activity & thus the bone formation.
FUNCTIONAL REGULATOR
FR III Class III
Mild Class III cases
The correction of class III Malocclusion is by dento-alveolar means, not because of skeletal growth modification
Registration of Bite Varies with the type used.
Move mandible forward by 4 – 6 mm.
Or edge to edge contact of incisors
2.5 to 3.5 occlusal clearance.
Correction of sagittal discrepancy in 2 or 3 stages.
3 dimensional effect of FR
Bionator 1.Light Appliance 2.Better Compliance 3.Full Time Wear
Timing for Bionator Therapy
Effective and stable when it is initiated immediately before the pubertal growth spurt. Optimal timing to start treatment with the Bionator is when a concavity is evident at the lower borders of both the second and the third cervical vertebrae (CVMS II).
In the long term, the amount of significant supplementary elongation of the mandible in subjects treated with the Bionator during the pubertal growth spurt is 5.1 mm more than that in untreated subjects with class-II malocclusion. Significant increments in mandibular ramus height and for a significantly more backward direction of condylar growth.
• Used in mix dentition.
• Major indication is in extremely deep bite.
• Used to bring mandible in forward position and to increase LAFH by eruption of posterior teeth…California Bionator.
• Can be used to close bite and maintaining bite.
• Protusion springs may be used in class II div2
Bionator
Lingual horseshoe of acrylic
Palatal spring
(Reverse coffin
spring)
Facets in the acrylic
which accepts maxillary
& mandibular teeth &
hold them in postured
position
Labial Bow
Twin BlockIndications
Class II div 1 Distal molar and canine relationship of at least half premolar
width Overjet more than or equal to 5mm Protrusion of maxillary incisors Class II skelatal type ANB≥ 4 Occlusal development ..late mixed dentition or early
permanenet dentition Normal & low angle cases
Effects of twin block Skeletal effects: mandibular length increses,during 1 yr, restrains
maxilla Dentoalveolar change: upper incisors tip back Lower incisors move forward Overjet reduction.,.(correction achieved by skelatal and dentoalveolar
reduction Correction of buccal segment achieved by combination of distal movement
of upper molars &forward movement lower molars ANB reduction Increased vertical dimensions..(inc lower facial height)mandibular plane
angle increases Reduction of facial convexity
Contraindications TMJ problems
Sk assymetries
Syndromic pts
Twin Block
Adams Clasp
Labial Bow
Inclined Plane
Modified
Adams Clasp
Bite blockBite block
Inclined Plane
In Function
Expansion Screw
ClarK 1988
“where there is a will there is a way”
Chapter 13
Jaw Orthopedic Functional
Appliances
Removable Functional Appliances
TOOTH BORN MONOBLOCK ACTIVATORS BIONATORS TWIN BLOCKS MAGNETIC APPLIANCE
TISSUE BORN FRANKEL FUNCTIONAL APPLIANCE
Fixed Functional Appliances
Flexible Fixed Functional Appliances (FFFA) Rigid Fixed Functional Appliances (RFFA) Hybrid Appliance Fixed version of RFA (fixed twin block , dynamix appliance) Elastics
• Fixed functional.
• should be used in permanent dentition.
• Easily tolerated by the patient.
• Should be changed after some time .
Fixed Functional AppliancesAdvantages Continuous stimulus for mandibular growth (24 hr use) They are smaller in size permitting better adaptation to functions such as a
mastication, swallowing, speech and breathing. Non-compliance Class II devices, which are able to treat Class II malocclusions
successfully, while reducing the need for patient co-operation and overall treatment time. Allows greater control by the orthodontist.
Disadvantages Application of force is transmitted directly to the teeth through a support system, the main disadvantage that may be encountered is dental movement that takes
place during treatment
APPLIANCE DISCRIPTION Can be compared to the artificial
joint between maxilla & mandible.
A bilateral telescopic mechanism keeps the mandible in continuous anterior position.
Appliance consists of a tube to which plunger fits. Tube is fixed to the distal end of maxillary molars & rod into the lower first premolars.
Herbst Appliance The Herbst appliance consists of two tubes, two plungers, axles and screws Type I is characterized by a fixing system to the crowns or bands through the use
of screws. It is necessary to weld the axles to the bands or crowns and then fix the tubes and
plungers with the screws Type II has a fixing system that fits directly onto the archwires through the use of
screws Disadvantage is the fracture of archwires
Type III is for anchorage
Type IV has a fixation system with a ball attachment, which allows greater flexibility and freedom of mandibular movement.
Disadvantage in relation to other similar appliances is that it needs brakes to stabilize the joint. The brakes are small and sometime difficult to fit. When a fracture occurs or a brake is lost, the appliance comes loose
FFF-ApplianceJasper Jumper
Jasper Jumper Herbst Appliance
Indicationsof FFFA Class I (An anchorage reinforcement)
Class II division 1 and 2
Class III malocclusions
Molar distalization
Midline discrepancy
Flexible Fixed Functional AppliancesInter-maxillary torsion coils, or fixed springs.
Advantages
Elasticity Flexibility Allow great freedom of movement of the mandible Lateral movements can be carried out with ease
Disadvantages
Fractures can occur both in the appliance itself (mainly in areas that have more acute angles) and in the support system (mainly in the lower arch)
If on one hand flexibility is an advantage, on the other hand it does tend to produce fatigue in the springs Tendency of the patient to chew on the appliance, possibly contributing to breakage or damage. It is not possible for the patient to completely open his mouth, depending on the way the system is fixed
onto the lower arch, good opening can be achieved. Expansive & replacement of broken parts adds cost Inventory Unhygienic but covering of springs make them hygienic
Mechanism of Action FFFAs allow the patient to close in centric relation
When the patient closes in centric relation, the contour of the bow should be significantly increased
By slightly overactivating the appliance in centric relation, the patient will automatically position the mandible forward. This is a natural response to decrease the force module and alleviate discomfort.
Clinical Relevance
In brachyfacial cases, due to their strong musculature, it is necessary to use more force (greater activation) than in dolicofacial cases.
If the patient has large cusps with good intercuspation, it will be necessary to exert greater activation on the spring.
Greater force for orthopedic effects while lesser for dento-alveolar movements
To maximize the dentoalveolar movements in the upper arch and minimize any loss of anchorage in the lower, the upper archwire is not tied back.
It can be used to obtain maximum anchorage, holding upper molars back as the upper incisors are retracted.
Unwanted Effects Due to the intrusive force on the upper molars, a posterior open bite is common
as well as posterior expansion due to the deflected force module.
Tendency for the lower molar to rotate mesiobuccally, causing a mild posterior
crossbite especially when the second molars have not been banded
Proclination of lower incisors..
Not recommended in mixed dentition, especially late mixed dentition to avoid
unwanted dental movements.
Jasper Jumper Intrusion and distalization of the upper molars, with occasional opening of the
posterior bite similar to that seen with a Herbst ppliance.
Some indication of condylar growth.
Anterior migration of the mandibular teeth through alveolar bone.
Intrusion of the lower incisors.
Advantage
comfortable because of its covering.
Disadvantages
The large inventory that must be kept,
the coating material may degrade
Fractures
Contd. Canines can be retracted against
mandibular dentition.
As the force modules cause asymmetric forces, it can be used to treat dental asymmetries.
Causes mandibular advancement and increase in LAFH.
Can be used in post surgical stabilization of class II patients.
Indications.
Dental Class II malocclusion.
Skeletal Class II with maxillary excess as opposed to mandibular deficiency.
Deep bite with retroclined mandibular incisors.
Midline Correction
Contra-indications.
Cases predisposed to root resorption.
Dental and skeletal open bites.
Vertical growth with high mandibular plane angle and excess lower facial height.
Minimum buccal vestibular space.
Rigid Fixed Functional Appliances RFFAs do not easily fracture but neither do they have elasticity or flexibility.
After fitting and activation they do not allow the patient to close in centric relation. This means that the mandible is in a forward position 24 hours a day creating greater stimulus for mandibular growth than with FFFAs.
Skeletal effects produced with this type of appliance are greater than with FFFAs
Mechanism of Action
Telescopic mechanism which encourages forward repositioning of the lower jaw as the patient closes into occlusion
Indications.
Dental Class II malocclusion due to retrognathic mandible Skeletal Class II mandibular deficiency.
Deep bite with retroclined mandibular incisors. They can be used as an anterior repositioning splinting patient with TMJ disorders.
Residual growth can be utilized in post adolescent patients. Can be used in mouth breathers.
Contra-indications.
Cases predisposed to root resorption.
Dental and skeletal open bites.
Vertical growth with high maxillomandibular plane angle and excess lower facial height.
TYPES OF APPLIANCE Bonded herbst (High Angle Cases)
Banded herbs
Flip locked herbst
Crowned herbst
The Flip-Lock Herbst Appliance
Reduced number of moving parts that can lead to breakage or failure.
Easy to use
Comfortable
Instead of a screw attachment, it has a ball-joint connector so it needs no retaining springs.
Less chairside time activation
Bonded Herbst Appliance
High Angle Cases
It is a wire reinfofced acrylic splint.
The pivots are fixed to the wire framework at distobuucal aspect of the upper first molar mesial aspect of lower first premolar.
Tube is fitted to the pivot in the upper molars & shaft is fixed to mandibular premolar region
BANDED HERBST Upper & lower first premolar & first molars
are banded.the tubes are fixed to pivots soldered to distobuccal aspect upper first molars.
The shaft or rods are fixed to pivots soldered to lower first premolar band.
CROWNED HERBST
Hybrid Functional Appliances
Hybrid appliances are specifically and individually tailored to exploit
the natural processes of growth and development.
These appliances blend several components designed to address
specific problems
Asymmetric mandibular deficiency or facial asymmetry in children
Condylar fracture
Fixed Version Of RFA
• Dynamax Appliance
• Fixed Twin Block
• Magnetic Appliances
• Elastics
Fixed version of RFA
Clip-on Fixed Functional Appliance Advantages of the Appliance
Patient co-operation is not required.
It works for 24 hours a day.
A full fixed appliance can be placed at the same time as the Class II correction is being carried out.
Treatment time is short because of full time wear.
There is no transitional phase between functional phase and the fixed phase so treatment time reduced.
Overlap of the functional and fixed phase further reduces treatment time.
It is less bulky than other functional appliances.
Fixed version of RFAJO March 2001
Clip-on Fixed FA
Inclined Planes
Occlusal blocks with lingual tube attachments
Occlusal blocks with palatal
tube attachments.
Disadvantages of the Appliance
Breakage of the Appliance
Construction of the Appliance.
Oral Hygiene Problems
Airways Clearance
Clip-on Fixed Functional Appliance
The results showed that this appliance was effective in correcting Class II malocclusion; the noncompliance rate was only 6%
Extra-oral force
Dento-facial orthopedics
Head Gears Orthopedic appliance that control growth of facial
structures
Various designs.
Used with growing patients.
USES OF HEAD GEAR CORRECTION OF SKELETAL CLASS II AND REDIRECTION OF GROWTH
;(excess growth of maxilla/deficient growth of mandible)Head gear restrain the forward and downward growth of maxilla by holding back the growth of upper jaw, allowing the lower jaw to catch up and thus the correction of class II.
MOLAR DISTILIZATION.head gear may be used to distalize maxillary molar to correct the class II molar relation ship or to gain space for relief of crowding.
AS AN ANCHORAGEIn some situations ,to maintain the bite, the orthodontist will not
want the back teeth to come forward. The headgear serves to hold them back to maintain anchorage.
USES OF HEAD GEAR REINFORCEMENT OF ANCHORAGE.
head gear can be used to reinforce anchorage in high anchorage cases.
MOLAR ROTATION.can also be brought about with the inner bow of headgear.
CORRECTION OF SKELETAL CLASS III.(deficient growth of maxilla/excess growth of mandible).; by protraction or reverse pull head gear that causes the anterior displacement of maxilla.
CORRECTION OF SKELETAL CLASS II AND REDIRECTION OF GROWTH ;(excess growth of maxilla/deficient growth of mandible)
CORRECTION OF SKELETAL CLASS II AND REDIRECTION OF GROWTH ;(excess growth of maxilla/deficient growth of mandible)
CORRECTION OF SKELETAL CLASS III
TYPES OF HEAD GEAR
High pull
Cervical pull
Combination pull
Reverse pull
Asymmetric Head Gear
TYPES OF HEAD GEAR
TYPES OF HEADGEAR
High pull Combination pull
Cervical Pull Reverse pull
Asymmetricheadgear
COMPONENTS PARTS OF HAEDGEAR
. Face bows;( Inner and outer bow)
. Release modules
. Straps or cushions
. Other items.
FACE BOW STYLES. KLOEHN
Regular
Cushion Loop
J-HOOK
ASHER
BITE PLATE
FACEBOW STYLES
Kloehn style
Bite plate
Asher facebow
Cushion loop
J -hook
BIOMECHANICS OF HEAD GEAR CENTER OF RESISTANCE OF MAXILLA AND MOLAR TOOTH.
BIOMECHANICS OF HEADGEAR The relation ship of line of action of force to the
center of resistance of maxilla or first molar determines whether translation (bodily )or rotation (tipping) takes place.
When a force does not pass through the center of resistance of the maxilla/molar, A moment is produced.
The direction of line of force can be changed by adjusting the length and position of outer bow.
High Pull Head Gear Bodily movement of molar
(no tipping) when line of force is passing through the center of resistance of molar.
Both backward and upward movement of molar.
When line of force is above CR --- mesial tip of crown and distal tip of root.
When line of force is below CR --- mesial tip of root and distal tip of crown.
Bodily movement of molar (no tipping) when line of force is passing through the center of resistance of molar, as determined by the outer bow length and position
Both backward and downward movements of molar.
When line of force is above CR ---mesial tip of crown and distal tip of root.
When line of force is below CR ---mesial tip of root and distal tip of crown.
The outer bow is always longer than that used in High pull.
Low Pull/Cervical Head Gear
BIOMECHANICS OF HEAD GEAR Similar considerations
apply to maxilla. Unless the line of force is through the center of resistance, rotation of maxilla occurs.
Control of line of force is easier when face bow inserted into the splint covering all teeth.
With all teeth splinted; it is possible to consider the maxilla as a unit and to relate the line of force to the center of resistance of maxilla.
RULE TO CHECK WHETHER THE LINE OF FORCE IS THROUGH THE CENTER OF RESISTANCE IN HIGH PULL AND CERVICAL PULL
HEADGEAR
In order to determine the proper position of outer bow. Use index finger to apply pressure in direction of head gear selected.
A)In case of high pull headgear we move index finger below the outer bow, pushing up and back. As the finger is moved on the outer bow applying force. The bow will move up between the lips.
B)In case of cervical pull headgear we move index finger above the outer bow, pushing down and back. As the finger is moved on the outer bow applying force. The bow will move down between the lips.
BIOMECHANICS OF HEADGEAR When the bow moves up, the roots of
maxillary first molar will move distally.
. When the bow moves down, the rootsof maxillary first molar will movemesially and crown distally.
. When the bow does not move. Theforce is through the center ofresistance of the maxillary first molarand molar will move bodily and notrotate.
BIOMECHANICS OF HEAD GEAR EFFECT OF THE LENGTH OF OUTER BOW.
The longer outer bow bend up and shorter bow bend down could produce the same line of force through the center of resistance of molar.
High Pull Head Gear Derives anchorage from parietal region. It
produces intrusion and distalization of teeth.
INDICATIONS. Open bite cases. High mandibular plane angle. Long face cases with an increase in lower
anterior facial height.
High pull headgear can be used as.
HIGH PULL HEADGEAR TO MOLARS. HIGH PULL HEADGEAR TO MAXILLARY
SPLINT HIGH PULL HEADGEAR TO FUNCTIONAL
APPLIANCE.
CERVICAL HEAD GEAR
The anchor unit in this head gear is nape of neck. It causes extrusion and distalization of molars along with distal movement of maxilla.
Indications:
short face,class II
Anchorage conservation.
early treatment of classII
Combination pull Headgear
Derives anchorage from at least two regions ; the neck and occiput. It causes distal and slight superior force on maxilla and dentition.
Protraction head gear. The rationale for protraction headgear is to apply heavy force
on the mid face in order to advance the maxilla anteriorly.
In this type inner bow is bent to achieve distal insertion ,outer bow is modified to make hook in premolar region for elastic attachment.
The center of resistance of mid face is difficult to locate but most studies shows it 5-10mm below the orbit.
Protraction head gear. A line of force closer to
center of resistance of mid face will deliver a translatory force and line of force closer to occlusal plane has rotational force.
Petit Face Mask For the protraction of
maxilla and maxillary dentoalveolar segments.
developing Class III pattern.
Cleft lip and palate patients.
Extra-oral elastics (heavy)
Asymmetric head gear. Asymmetic force is
achieved with a head gear by using an asymmetric outer bow,can be useful in regaining bilateral but asymmetric lost space.
Time, Duration and Force of Headgear Therapy. FORCE. 500 TO 700gm(orthopedic )150-
200gm(orthodontic force).
DURATION 12 -14hrs /Day, emphasis on wearing it from early morning.
Treatment Duration. 12 TO 18 Months.
TREATMENT EFFECTSSKELETAL EFFECTS Frontomaxillary,zygomaticotemporal,zygomaticomaxil
lary n pterygopalatine r most imp growth sites for development of maxilla.
head gears act by compressing the sutures thus restricting the normal downward n fowad growth of maxilla.
DENTAL EFFECTS Distalization of molars. Extrusion and intrusion of molars
SIDE EFFECTS OF HEAD GEAR
Compensatory erruption of max And mand molars but can be controlled by fixed lingual arch.
Distal tipping of max molars.
Increased facial height.
SIDE EFFECTS OF HEAD GEAR