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Extraoral Orthodontic Appliances
Mohammed Almuzian
JANUARY 1, 2013
1
Contents• Definition
• Types of extra-oral appliances
• History
• Uses (indications of HG)
• Anchorage reinforcement
• Interceptive uses
• Dental movement
• Growth modification or orthopedic appliances
• Studies about the effects of HG
• Types of Headgear
• Headgear with facebow
• J hook facebow
• Asymmetric Headgear
• Headgear to URA/Functional appliance combination
• Nudger appliance HG
• B. En mass removable appliance
• C. HG and Dynamax
• D. Headgear to upper part of the Twin block
• E. The Intrusive Myofunctional Appliances
• Controversies of the use of TPA with HG
• Complications of Headgear appliances
• Four Types of Headgear Injuries in Europe
• Safety Advises and mechanism in the use of Headgear and Facebow
• Safety release headgears
• Safety facebows
• Miscellaneous safety products
• In case of HG/URA combination
, Mohammed Al-Muzian, University of Glasgow, 2013
2
• Written and verbal instruction & advice
• Force affecting factors
• Direction
• Position of the force in relation to center of resistance
• Magnitude
• Duration
• Decline in our personal use of headgear
• Protraction Headgear
• Definition
• History
• Indications
• Timing
• Effects
• Evidence based short term effectiveness of PH
• Evidence based long term effectiveness of PH
• Protraction face mask system
• Chin Cups
• Types
• Best patient for Chin cup therapy
• The effects of chincup therapy
• Reverse chin cup therapy
• Summary of the evidence
• References
, Mohammed Al-Muzian, University of Glasgow, 2013
3
Extraoral orthodontic appliances
Definition
It provides a means of applying anterior, posterior or vertical directed forces to
the dentition and skeletal complex from an extra-oral source. (Turner 1991)
Types of extra-oral appliances
1. Headgear with facebow or J hook.
2. Reverse facial mask
3. Chin cap or reverse chin cap
History
HG introduced in the late 1890's by Kingsley then by
Angle in 1910.
By 1920, it was disused as it was believed that intra-oral
elastics would suffice (Angle).
Re-used again in the 1940's after lateral cephalometric
radiographs showed the adverse effects of intra-oral
elastic traction.
Uses (indications of HG)
1. Anchorage reinforcement
Reinforcement of anchorage to prevent forward movement or to counteract
extrusion of anchor molars.
, Mohammed Al-Muzian, University of Glasgow, 2013
4
Feldmann, 2009, RCT to measure the anchorage loss with Onplant (1), TAD (2),
EOT (3) & TPA (4). They found that after levelling/aligning phase: the
anchorage was stable in the group 1,2 & 3 while group 4 showed 1.0 mm.
while after space closure phase, the anchorage was stable in the group 1 & 2 but
group 3 & 4 showed 1.6 and 1.0 mm of mesial drift of molars respectively.
Feldmann, 2012, measured the patients’ perceptions in term of pain, discomfort,
and jaw dysfunction with Onplant (1), TAD (2), EOT (3) & TPA (4). The results
confirm that there were very few significant differences between patients’
perceptions of skeletal and conventional anchorage systems during orthodontic
treatment
TADs or HG? Junqing in 2008 showed again a better result by TADs in
comparison with HG.
2. Interceptive uses
A. To provide space for spontaneous eruption of ectopic canine as interceptive
treatment with a success rate of 80% compared to 50% in control group.
(Leonardi, 2004).
B. Uprighting impacted U6s against UEs.
C. To maintain the space after premature loss of primaries.
D. To regain a lost space due to mesial migration of molars (premolar crowding
cases).
3. Dental movement
I. Distalization movement
To correct less than 1/2 unit Class II molar relationship aiming to correct mild
increased in the OJ in non-extraction cases or to provide space to relief mild
crowding
, Mohammed Al-Muzian, University of Glasgow, 2013
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To provide extra space in sever space deficiency in which extraction fail to
provide sufficient space.
HG with J hook to individually retract U3 or rarely, retract L3 (problem with
patient toleration)
Differential (asymmetric) movement for treatment of ML problems
II. Transverse teeth movement (minor maxillary dental expansion)
III. Vertical teeth movement (intrusion or extrusion of UBS or ULS) or anterior
teeth when it is combined with auxillary wires like tandem (Hans)
IV. Teeth de-rotation.
4. Growth modification or orthopedic appliances
Appliances that restrains anterior and/or vertical growth of the maxilla
The best age is 12-13 years since early treatment offer no advantages over
late single phase treatment (Tulloch, 2004, Dolce 2007). Ghafari 1998 suggest
the use of HG before loss of Es in order to use the Leeway space.
It acts by influencing the pterygopalatine, fronto-maxillary, zygomatic
maxillary sutures.
Studies about the effects of HG
1. Dental effect 1. Enmass retraction with HG plus extraction of the
upper second molars claimed to achieve 6mm molar
distalisation (Orton, 1996).
2. Atherton et al. (2002) came to the conclusion that the
most distal movement of the molars that could be
achieved was in the range of 2 - 2.5mm.
3. Firouz 1992 showed that the amount of intrusion
achievable by HG is 0.5mm
, Mohammed Al-Muzian, University of Glasgow, 2013
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4. Melsen and Dalstra (2003) in their retrospective
study found that the total displacement of the molars
in patients wearing cervical headgear for an 8-month
period did not differ from that of an untreated group
when re-evaluated 7 years later
5. Bondemark (2004) in a randomised controlled trial
compared HG and the distal jet and found that the
distal jet was more effective than the HG in creating
distal movement of maxillary first molars but
anchorage loss was greater with the distal jet.
2. Skeletal changes 1. Mills 1978 in a review, stated a maxillary growth
suppression effect of 1-2 mms is possible in humans
with Kloehn bows
2. Wieslander, 1993,1mm of maxillary growth restraint
achieved over a 10 year period that persists post-
treatment
3. Tulloch et al 1997 (class II D1 OJ 7mm, HG, Bionato
or CG for 15 months) concluded that the bionator
produced some mandibular change, whereas, with the
headgear, there was some maxillary restraint. In the
TG (HG or Bionator) the improvement in the ANB in
70-80% while no improvement in 20%. In the CG no
improvement 50%, improvement 30% and worsening
20%.
4. Then Tulloch 1998 followed the patient and found
that skeletal improvement are lost after 1 year.
5. Keeling et al 1998 (HG/Biteplane, Bionator, CG, OJ
, Mohammed Al-Muzian, University of Glasgow, 2013
7
7mm for 2 years or until class I achieved) suggested
that a headgear biteplane combination resulted in no
restraint of the maxilla but forward positioning of the
mandible.
6. Ghafari et al 1998 suggested that headgear produces
some maxillary restraint and the Fränkel, mandibular
growth increase.
3. compliance HG failure rate 5% for female and 25% for male
(Ghafari 1998)
Types of Headgear
A. Headgear with facebow
Original Kloehn bow
Kloehn loop style facebow.
Asher Facebow
Bite Plate Facebow
B. J hook facebow (not used anymore in UK for safely reasons)
C. Asymmetric Headgear
Power-arm face-bow
Soldered-offset face-bow
Swivel-offset face-bow
Spring-attachment face-bow
D. Headgear to URA/Functional appliance combinations
Nudger appliance HG
En mass removable appliance
HG and Dynamax
Headgear to upper part of the Twin block
, Mohammed Al-Muzian, University of Glasgow, 2013
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The Intrusive Myofunctional Appliances
1. The Van Beek appliance
2. Tauscher appliance
3. The Buccal Intrusion Splint (BIS)
4. The Maxillary Intrusion Splint (MIS)
5. The Maxillary Intrusion Splint and Lower Traction Plate (CONCORDE)
In details
1. Headgear with facebow
A. Original Kloehn bow
It invented by Kloehn 1947 after World War II.
Inner bow diameter 1.13mm
Outer bow diameter 1.45mm
B. Kloehn loop style facebow.
The loop aids in providing an attachment to
elastics.
C. Asher Facebow
Used by Dr. Ron Roth
Intrudes anterior teeth
Pushes on Archwire
D. Bite Plate Facebow
Intrudes anterior teeth, Pushes on anterior teeth,
two main styles: loop style or regular style
, Mohammed Al-Muzian, University of Glasgow, 2013
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2. J hook facebow (not used anymore in UK for safety reasons)
Uses
Distalize the canine . If force heavy enough - then it can
move 5/5 and 6/6 distally also.
Intrusion of anterior teeth but less efficient than TADs
(Degushi, 2008)
It also restrains maxillary development.
"J" hook headgear can also be used asymmetrically to
resolve a centre line problem by judicious use of the
hooks to contralateral upper and lower canines e.g. UL3 &
LR3.
Mechanics
I. J hook traction engaged in stops soldered or crimped onto the archwire between
the lateral incisor and the canine or attached to an attachment on the tooth
directly.
II. Hickman (1974) - devised a headgear which will accept 2 or even 3 "J" hooks
each side.
Problems
I. Accidental injuries
II. Root resorption. Linge and Linge 1983
III. The headgear's expansion effect on the arch wire. For this reason, it is important
to contract the arch wire from the canines distally in order to resist this effect
(Berman, 1976).
IV. "J" Hook straight pull headgear to the lower arch in Class III cases cause the
mandible to rotate in clockwise direction.
V. There is significant binding and friction, not only where teeth slide along the
archwire but also within the headgear mechanism itself because the headgear
, Mohammed Al-Muzian, University of Glasgow, 2013
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wires that attach to the teeth tend to bind against their protective sleeves.This
makes it difficult to control the amount of force, and more net force on one side
than the other may lead to an asymmetric response. In fact, it is usual if space
does not close faster on one side than the other.
VI. Degushi 2008 compared TAD with J hook for intrusion and found the
result is 3.1 and 1.3mm respectively.
3. Asymmetric Headgear
Results in more movement on the side with the longer outer bow according to
Castagliano's Theorum
Problem: it lead to that same tooth becoming susceptible to lingual crossbite
, Mohammed Al-Muzian, University of Glasgow, 2013
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Types of asymmetrical HG
1. POWER-ARM FACE-BOW
2. SOLDERED-OFFSET FACE-BOW
3. SWIVEL-OFFSET FACE-BOW
4. SPRING-ATTACHMENT FACE-
BOW
4. Headgear to URA/Functional appliance combinations
A. Nudger appliance HG
Uses:
1. Used for true unilateral space loss with
subsequent loss of space.
, Mohammed Al-Muzian, University of Glasgow, 2013
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2. Class II subdivision
3. Correction of ML deviation
4. It can be used bilaterally to gain space to correct OJ or relief crwoding
Design:
1. Band molar teeth
2. Fit URA with palatal cantilever spring 0.7mm SS on the molar requiring distal
movement.
3. Retention from Adam clasp on premolars, Southern end clasp on incisors but on
molars try to use Plint clasp because of the presence of the molar bands.
4. Alternative ways of differential movement of 6/6: asymmetrical extraction of the
7s with normal Kloehn Bow and/or URA screw appliance
Mechanism of action:
1. An upper removable appliance (URA) with palatal finger springs acts to tip the
crown of the molar distally.
2. High-pull headgear at night, directed above the center of rotation of the
molar, acts to distalise the root and hold the movement achieved during the
day time by the URA, (Cetlin & Ten Hoeve, 1983).
B. En mass removable appliance
1. It involves upper removable appliance to which a headgear (200-300gm per side
for 14 hours) is attached through a Facebow or it the HG can be attached to
molar tubes and over it there is a URA.
2. Extraction of the upper second molars may be required and this claimed to
achieve 6mm molar distalisation (Orton, 1996).
, Mohammed Al-Muzian, University of Glasgow, 2013
13
C. HG and Dynamax
D. Headgear to upper part of the Twin block
1. Park 2001used TB with HG and torqueing spring and
compared it to conventional TB and found that better
control of ULS inclination.
2. It is also indicated in high angle class II malocclusion
E. The Intrusive Myofunctional Appliances
1. The Van Beek appliance
Described by Pfeiffer (1972) to reduce the duration of
treatment significantly.
This prompted Van Beek to design a simplified short
outer arm facebow embedded in the acrylic part of the
Harvold activator (Myotonic functional appliance) or HG
tubes within the acrylic to accept the facebow for the high-pull headgear.
There is full palatal coverage and fully extended lingual flanges
300 gms of force/12 hours a day
2. Tauscher appliance
It is similar to Van Beek but with HG attached to
posterior segment of activator and with torqueing
spring
3. The Buccal Intrusion Splint (BIS)
This appliance consists of an acrylic palatal baseplate which is clear of the upper
anterior teeth and with occlusal capping on the teeth in occlusion.
There are double Adams cribs present on the upper first permanent molars and
first premolars and molar tubes embedded in the occlusal capping acrylic to
accept a Kloehn facebow near the area of maxillary rotation (premolar area).
, Mohammed Al-Muzian, University of Glasgow, 2013
14
There is a midline screw present in the palatal acrylic.
This appliance is used to treat skeletal anterior open bites by intrusion of the
upper buccal segment teeth.
4. The Maxillary Intrusion Splint (MIS)
• This appliance consists of an acrylic baseplate which extends over the occlusal
surfaces of all teeth and onto the labial surfaces of the upper anterior teeth.
• There are Adams cribs present on the upper first permanent molars and first
premolars, along with a Southern clasp on the upper central incisors.
• There are headgear tubes present within the molar capping
• This appliance is designed to be used for patients with a Class II division 1
malocclusion and a "gummy smile" with an overjet of 6 to 8mm. .
5. The Maxillary Intrusion Splint and Lower Traction Plate (CONCORDE)
• This is a two part appliance which consists of a maxillary intrusion splint as
described above along with a lower appliance.
• The lower appliance consists of an acrylic baseplate with no occlusal or incisor
capping. There are double Adams cribs present on the lower first permanent
molars and second premolars, and a semi-fitted labial bow on the lower incisors.
• There is a lingual hook on the lingual aspect of the acrylic baseplate to enable
elastics to be attached to the midpoint of the facebow.
• The selection criteria are the same as for the maxillary intrusion splint but these
combined appliances work more effectively at reducing overjet between 9 to
18mm than the maxillary intrusion splint alone.
• This appliance combination can also be used for the treatment of a severe Class
II division 1 malocclusion with a "gummy smile" and an average face height.
, Mohammed Al-Muzian, University of Glasgow, 2013
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Controversies of the use of TPA with HG
For minimal overbites and small anterior open bites, successful results can be
achieved by careful control of the buccal segments in the vertical dimension.
The point of application of the force however tends to result in more intrusion of
the buccal cusps than the palatal cusps.
The use of a transpalatal bar on the first molars can prevent dropping of the
palatal cusps of the first molars.
The transpalatal bar design used was fitted 1-2 mm off the palate.
In a study by Wise et al (1994) which compared 20 non-extraction patients in
which a transpalatal bar was used for at least 5 months with similar patients in
whom it was not used, no significant differences were found between the two
groups.
Complications of Headgear appliances
Teeth related
AP Distal tipping of the molars& Distal tipping of the canine in
case of J hook
Transversely Increased buccal crown torque (reduced by rigid TPA, Scissor
bite effect of J hook, Crossbite effect of Kloehn bow and
asymmetrical HG(this can be counteracted with either a
removable upper appliance with screw expander or by
widening (expanding) the inner bow).
Vertically Increase anterior facial height and gingival show due to
mandibular clockwise rotation as a result of molar extrusion
and the patient will show CL2 profile (O'Reilly et al.1993).
Rotation of the molars and canines
Patient related
Patient Cooperation Not all patients are honest in actual compliance. Using time
charts can increase co-operation (Cureton et al. 1992, 1993).
Biological variability Growth may be unfavorable
Pain Heavy force and necrosis
, Mohammed Al-Muzian, University of Glasgow, 2013
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Root resorption a possibly with J hook headgear and this should be monitored
radiographically, e.g. long cone Periapical
Nickel allergy Contact dermatitis-type IV delayed hypersensitivity immune
response (Rahilly and Price, 2003).
Intra-oral injuries Oral soft tissue injuries
Extra-oral injuries Facial and skin trauma
Rarely eye injuries (0.12% chance as per the AAO survey in
1982) can occur whilst wearing headgear with a serious
consequences involving the entrance of the oral bacteria in
the eye with subsequent impaired vision, loss of eye (Holland
1985), sympathetic opthalmitis, (Samuels and Jones, 1994;
Booth-Mason and Birnie, 1988), cavernous sinus thrombosis,
Chaushu, 1997.
Four Types of Headgear Injuries in Europe
Samuels 1993 (23 countries studied)
1. Incorrect handling during fitting or removal (8%)
2. Unintentional nighttime disengagement (71%)
3. Accidental disengagement while playing (17%)
4. Bully pulls headgear (4%)
Safety Advises and mechanism in the use of Headgear and Facebow
From Postlethwaite (1989) and Samuels 1993
1. Safety release headgears
Snap away mechanics: (easy release mechanics) Means that they are design to
break-away when excessive force applied to HG. This was developed by
Postlethwaite in 1989. It aims to prevent the catapult injuries.
NOLA system: same as anti-coil device but the device attached to the face bow
not the HG.
, Mohammed Al-Muzian, University of Glasgow, 2013
17
Ideal physical properties for the HG safety mechanism according to the study of
Stafford on 1998:
1. Minimal extension: it means the amount of extension of the facebow from its
attachment with the molar bands before it break-away (stop releasing force). So
if accidental force applied in a direction to dislodge the facebow, this system
(anti-recoil device) will start working. It should be from 10mm-25mm
2. Low force: it means the amount of force applied to the facebow before it stops
release the force or break-away (Anti-recoil device)
3. High Consistency: which means the release point should be constant in all types
of HG after prolonged repeated use.
2. Safety facebows
a. Locking mechanism (NiTom): helps to avoid accidental remove of the facebow
which act by special locking device behind the distal end of the inner bow thus
preventing accidental dislodgment of the facebow. This is developed by Samuel
in 2000.
b. Re-curved reverse entry inner bow: it designed by Lancer Pacific but it is
difficult to use by the patient.
c. Locating elastic: Like class I elastic attach the inner bow to the teeth to stabilize
the facebow.
3. Miscellaneous safety products
A. Safe end (blunt end)
B. MASEL safety strap (rigid neck strap)
It is easy and cheap.
Works by adding an additional rigid safety strap to the HG to minimize facebow
movement and dislodgment.
, Mohammed Al-Muzian, University of Glasgow, 2013
18
4. In case of HG/URA combination
a. Clip-over appliance. It means that the facebow should attached securely to
molar band while the URA clip over the bands
b. Integral face bow (soldering the inner bow to the URA)
c. Locking mechanism (same as point B)
5. Written and verbal instruction & advice
1. The way of inserting and removing the HG which include:
Place the facebow first
Ensure that the safety mechanisms are active during use.
Then place the headgear
Remove external headgear attachment before the inner bow. Never remove or fit
the headgear in one piece
2. Do not wear headgear while playing sports.
3. If the headgear comes detached during sleep, stop wearing the headgear
immediately and contact your orthodontist the next day.
4. If any eye injury associated with the headgear occurs; it must be treated as a
Medical emergency.
5. Bring your headgear to each appointment and report any problems to your
orthodontist.
Force affecting factors
Bowden 1978
1. Direction
Theory of Directional Forces (DF) - Merrifield and Cross (1970), DF angle =
"directional force angle" = angle made by the headgear line of force and the
functional occlusal plane.
, Mohammed Al-Muzian, University of Glasgow, 2013
19
If DF > 60º. (vertical pull) - a force is produced which is 0 distal movement and
3/3rds intrusion upon 6/6.
If DF 20-50º. (high pull) - a force is produced which is 1/3rd distal movement
and 2/3rds intrusion upon 6/6.
If DF = 0-10º. (straight pull) - a force is produced which is 3/3rd distal
movement and 0 intrusion upon 6/6.
If DF = -10 to -20º (low pull) - this gives the force which is 1/3rd extrusive and
2/3rds distal upon 6/6.
2. Position of the force in relation to center of resistance
Two variables could determine the position of force in relation to center of
resistance includes:
A. Length of outer bow
B. The direction of pull
C. Clinical situation of thU7s (Unerupted 7's move distally in response to the
moving first molar. Fully erupted second molar causes more distal crown
tipping)
See these different scenarios:
a. Outer Arm short
If above center of resistance i.e. high pull - causes intrusion and distal tipping of
the root.
If below centre of resistance i.e. low pull - causes
extrusion and distal tipping of the crown.
Outer bow at the trifurcation point of 6/6 (center of
resistance. The result is pure translation. (this was
supported by paper from Bowden (1978) and Yoshida et al (1995)., Mohammed Al-Muzian, University of Glasgow, 2013
20
b. Outer arm long
If above centre of resistance i.e. high pull - causes intrusion and distal tipping of
the crown.
If below centre of resistance i.e. low pull - causes extrusion and distal tipping of
the root.
Outer bow at the trifurcation point of 6/6 (center of resistance. The result is pure
translation. (this was supported by paper from Bowden (1978) and Yoshida et al
(1995).
3. Magnitude
A. Different level of force for different requirements (and different clinicians!)
Weislander (1972) achieved 2mm of distillation of A point over 3 years with
only 300g of force
Armstrong (1971), Graber (1977) all used forces in excess of 400g, and
sometimes 2 or 3 times that amount to achieve rapid orthopaedic translations
Firouz (1992) showed that the rate of anterior displacement of A point was
significantly decreased by applying 500g of counter force.
Watson (1978) demonstrated that the ANS could move distally by as much as
4mm in 1 year by applying 1000g bilaterally.
A. Conclusion:
Force levels of 250-300g per side is adequate for anchorage
Force levels of 400-500g per side is adequate for teeth movement.
Force levels of 800-1000g per side is adequate for skeletal effects
4. Duration
Anchorage: 10 hours per day.
Distal movement:12-14 hours per day
Orthopaedic: 12-14 hours per day.
, Mohammed Al-Muzian, University of Glasgow, 2013
21
Cureton et al. (1993) recommend the use of headgear charts routinely. Recently
the monitoring device like the Affirm headgear traction module has been used
(electronic timer) (Clark et al 2003)
Decline in our personal use of headgear
1. More class 2 elastics being employed
2. More lower incisor proclination accepted
3. Functional appliances which have better compliance
4. Fixed functional
5. Self-ligating brackets seem to reduce anchorage demands (not proven) and favor
earlier use of lighter class 2 traction
6. TADs have revolutionized intra-oral anchorage possibilities
Protraction Headgear
Definition
Means of applying anterior directed forces to teeth and/or skeletal structures
from an extra-oral source
History
The technique of maxillary protraction is based on work by Nanda (1978), with
rhesus monkeys in which he showed that a force of approximately 500g could
produce anterior displacement of the maxilla
It is appropriate to refer to this type of treatment as facemask therapy.
Indications
A. Treatment of maxillary retrusion. An ideal case would be;
, Mohammed Al-Muzian, University of Glasgow, 2013
22
1. Patient’s factors
Good co-operation
No familial prognathism
2. Growth
Young growing patient
3. Soft tissue
Acceptable facial aesthetics
4. Skeletal
Mild skeletal discrepancy (ANB < -20 )
Normal MMPA
No asymmetries (Symmetrical condylar growth)
5. Dental
-2mm reverse OJ or edge to edge relationship
Retroclined ULS
Proclined LLS
6. Displacement
Functional shift
B. Reinforcement of anterior anchorage and dental protraction allowing closure of
space from behind in patients suffering from hypodontia
C. Stabilization following maxillary osteotomy/distraction osteogenisis
D. Rotate arch segments in cleft palate patients
E. Remove hyper-anterior contact in TMJ internal derangement cases,
, Mohammed Al-Muzian, University of Glasgow, 2013
23
Timing
1. Dental age: McNamara (1987) suggested that the optimal time for treatment is
in the early mixed dentition, coincident with the eruption of the upper permanent
incisors.
2. Skeletal age: Baccetti et al (1998) showed that the early treatment group CVM2
showed effective forward displacement of the maxillary structures whereas the
late treatment group CVM3 showed no change compared with controls
3. Chronological age: Other investigators have suggested that for optimal
orthopaedic effects, treatment should be initiated before the patient is 9 years old
(Proffit, 2000).
4. Kim et al., 1999, meta-analysis of effectiveness of protraction HG concluded it
was less effective on patients >10yrs
Effects
1. Correction of a centric occlusion-centric relation discrepancy. This correction
happens relatively rapidly in patients with an edge to edge relationship and
associated displacement
2. Maxillary skeletal protraction
3. Proclination and forward movement of the maxillary dentition
4. Lingual tipping of the lower incisors
5. Redirection of mandibular growth in a downward and backward direction,
resulting in an increase in lower anterior facial height
Evidence based short term effectiveness of PH
Mandall, 2010 (similar to study of Ngan 1998)
Early Class III orthopaedic treatment with protraction face mask in
patients less than 10 years of age is skeletally and dentally effective in the short
term 15 months. (After 15 months of treatment, children undergoing early
, Mohammed Al-Muzian, University of Glasgow, 2013
24
facemask therapy had 1.3 degrees more forward movement of SNA, almost
2degrees less forward movement of SNB and an overall ANB improvement of
around 2.6 degrees when compared to the control group. In addition, the overjet
improved by more than 4 mm and the relative PAR score by more than 40% in
the facemask compared to the control group. Thus, early class III protraction
facemask treatment in patients under 10 years of age would seem to be
skeletally and dentally effective in the short-term)
70% of patients had successful treatment, defined as achieving a positive
overjet.
Early treatment does not seem to confer a clinically significant
psychosocial benefit.
No negative effect on the TMJ
Evidence based long term effectiveness of PH
Mandal 2012: Early Class III orthopaedic treatment with protraction face
mask in patients less than 10 years of age is skeletally and dentally effective
after 3 years of treatment.
Masucci 2011: RME/FM therapy led to successful outcomes in about
73% of the patients. Significantly improved sagittal dentoskeletal relationships.
These favorable changes were mainly due to significant improvements in the
sagittal position of the mandible, but the maxillary changes reverted completely
in the long term. This treatment not induces a tendency of bite opening or
increased vertical relationship.
A Cochrane review by Watkinson in 2013. This review looked at the use
of four different types of orthodontic treatment for correcting prominent lower
front teeth in children.-Facemask-Chin cup-Mandibular -Tandem traction bow
appliance. This review found some evidence that the use of a facemask
, Mohammed Al-Muzian, University of Glasgow, 2013
25
appliance can help to correct prominent lower front teeth on a short-term basis.
There was no evidence available to show whether or not these short-term
changes will still be maintained until the child is fully grown. There was not
enough evidence to support any other types of treatment for prominent lower
front teeth.
Protraction face mask system
A. Types Extraoral part
1. Protraction Headgear (Hickham)
2. Facial Mask (Delaire)
3. Suborbital Protraction Appliance (Grummons)
Advantages: frame more rigid, no force on TMJ, no LLS
retroclination, easy to adjust and wear during sleep
Disadvantages: not esthetic due to midfacial support
4. 4. Nola protraction appliance
5. Petit style face mask
The Petit style with a single central vertical bar is also well
tolerated and recent price changes have made it economically
much more attractive.
, Mohammed Al-Muzian, University of Glasgow, 2013
26
B. Intraoral part:
1. In order to maximize the amount of skeletal change in young children, a
removable full coverage acrylic splint is used with a protraction headgear
(Proffit 1986).
2. McNamara (1987) has described the use of a Biocryl and wire splint that is
bonded in the mouth. The splint material should be at least 3 mm thick with a
0.045" stainless steel wire framework. The two halves of the splint are joined by
an expansion screw. Traction hooks to receive the elastics from the headgear are
placed in the first premolar region.
3. Some recommend using an intraoral bone plate to support the PHG force.
Systematic review to compare the dentally anchored face mask with skeletally
anchored one by Major (2012) in Canada, he found Approximately 3 mm of
horizontal A-point movement is predictably attainable with the skeletal one in
comparison to dental one..
C. Rapid maxillary expansion
Advantages (Haas 1973).
1. Sutural loosening
2. Correct transverse discrepancy that commonly associated with class III
malocclusion
3. Displace the maxillary complex anteriorly. This is due to butterfly effect of
expansion at the Midpalatal suture and because of the anterior sloping of the
facial sutures
Evidences
, Mohammed Al-Muzian, University of Glasgow, 2013
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1. Many clinicians use protraction with a facemask following or simultaneously
with palatal expansion, because some evidence suggests that the expansion
makes antero-posterior skeletal change more likely. Kim et al (1999)
2. There is other evidence that the expansion is optional and should be dictated by
the maxillary arch width related to the lower arch width, Vaughan 2005.
D. Techniques
1. First step is to fabricate and bond/cement the rapid maxillary expansion
appliance
2. Appliance is activated once per day until the desired increase in maxillary width
has been obtained.
3. If patients do not need an increase in maxillary width, the appliance is still
activated for 7-10 days to disrupt the maxillary sutural system and promote
maxillary protraction (Haas, 1965)
4. After the patient activated the maxillary appliance for 7-10 days protraction
headgear is fitted.
E. Force level:
1. Moving maxillary anterior teeth forward: 400g per side, 12-14h/day
2. Maxillary protraction : 800g per side, 14h/day
3. Overcorrect to compensate for mandibular growth
4. Active treatment should be limited to 9-12 months because of the risk of
decalcification of the dentition
F. Force direction:
1. To avoid bite opening, place protraction elastics near maxillary bicuspids,
2. Force vector should be 15-30 degree below the horizontal
3. To avoid irritation to the lip, use crossed elastic,
4. Pay special attention to airway and tongue posture
5. Ishii et al (1987) describe the effects of providing the protraction force from the
first molars or the premolar region. Protraction from the first molars results in , Mohammed Al-Muzian, University of Glasgow, 2013
28
more anterior movement and a forward and upward rotation of the maxilla;
protraction from the premolars results in less forward movement but less
tendency to upward and forward rotation.
G. Transitional period
After treatment objectives have been achieved, the patient can be retained with a
number of appliances:
The facemask,
Acrylic maxillary retainer,
FR-3 appliance
Chin cup (seldom used).
H. Post protraction treatment consideration
1. As mandibular growth exceeds maxillary growth during adolescence, early
Class III correction may be lost during the teenage period. The patients and
parents should again be warned of the possibility of orthognathic treatment if
growth is unfavorable
2. Upper labial root torque during fixed appliance stage: Most class 3 patients
demonstrate considerable proclination of the upper labial segment at the end of
treatment. Catania et al (1990) recommend in his case report to use inverted U
incisor bracket to counteract the effect of proclination.
Chin Cups
The idea of this appliance is that because the condyle is a growth site, the
growth impeded by extra-oral force (Graber, 1977).
Despite success in animal experiments, most human studies have found
little difference in mandibular dimensions between treated and untreated
subjects (Sugawara et al, 1990).
, Mohammed Al-Muzian, University of Glasgow, 2013
29
Chincup appliances greatly improve the skeletal profile in the short term
such changes are however rarely maintained during the pubertal growth spurt
Force 500g per side 12-14 h/day for 4-5 years.!!!! Once the anterior
crossbite was corrected, the patient was instructed to wear the chin cup at least
10 hours per day until slight Class II canine and molar relationships were
established.
The best age is before canine and premolar erupt (CS2-CS3 maturity) this
is the first growth spurt of mandible, the second one when 7 and 8 erupt CS4-
CS6 (Bacceti, 2005).
Types: occipital pull, used for patients with mandibular prognathism or
vertical pull, used for patients with increased anterior face height
Best patient for Chin cup therapy
Ko et al (2004)
1. Mild Skeletal III, ability to achieve edge to edge incisors
2. Short vertical facial height (.Chincup cause clockwise rotation of the
mandible.
3. Proclined or upright LLS (Chincup cause lingual tipping of the lower incisors
(Thilander 1963)
4. Absence of severe facial and dental asymmetry
The effects of chincup therapy
(Thilander 1963)
Retardation of mandibular growth. Effective at reducing mandibular
prognathism before puberty but this is then lost with continual growth,
Sugawara et al., 1990
Remodelling of the condyle and glenoid fossa , Mohammed Al-Muzian, University of Glasgow, 2013
30
Backward rotation of the mandible
Closure of the gonial angle
Result in lingual tipping of LLS,
Reverse chin cup therapy
1. Developed in Germany in 2012 by Rahman 2012 show
similar result when the reverse chin cup therapy compared to
face mask therapy in RCT involving 42 samples at age of 8- 9
years.
2. Reverse chin cup therapy is able to produce forward
movement of the maxilla in the growing child associated
with lingual tipping of the lower incisors and labial tipping of
the uppers.
3. The point of application of protraction elastics from the
upper removable appliances was similar for both groups. All patients received
the same protraction force of 500 g per side with a 30 degree downwards pull.
4. The proposed advantages of the new reverse chin cup design were that it was
smaller and less bulky than other protraction appliances, therefore encouraging
children to wear it.
Summary of the evidence
Dental effect,
1. Enmass retraction with HG plus extraction of the upper second molars
claimed to achieve 6mm molar distalisation (Orton, 1996).
2. Atherton et al. (2002) came to the conclusion that the most distal movement
of the molars that could be achieved was in the range of 2 - 2.5mm.
3. Firouz 1992 showed that the amount of intrusion achievable by HG is
0.5mm
, Mohammed Al-Muzian, University of Glasgow, 2013
31
4. Melsen and Dalstra (2003) in their retrospective study found that the total
displacement of the molars in patients wearing cervical headgear for an 8-
month period did not differ from that of an untreated group when re-
evaluated 7 years later
5. Bondemark (2004) in a randomised controlled trial compared HG and the
distal jet and found that the distal jet was more effective than the HG in
creating distal movement of maxillary first molars but anchorage loss was
greater with the distal jet.
Skeletal changes
1. Mills 1978 in a review, stated a maxillary growth suppression effect of 1-2
mms is possible in humans with Kloehn bows
2. Wieslander, 1993,1mm of maxillary growth restraint achieved over a 10
year period that persists post-treatment
3. Tulloch et al 1997 (class II D1 OJ 7mm, HG, Bionato or CG for 15 months)
concluded that the bionator produced some mandibular change, whereas,
with the headgear, there was some maxillary restraint. In the TG (HG or
Bionator) the improvement in the ANB in 70-80% while no improvement in
20%. In the CG no improvement 50%, improvement 30% and worsening
20%.
4. Then Tulloch 1998 followed the patient and found that skeletal improvement
are lost after 1 year.
5. Keeling et al 1998 (HG/Biteplane, Bionator, CG, OJ 7mm for 2 years or
until class I achieved) suggested that a headgear biteplane combination
resulted in no restraint of the maxilla but forward positioning of the
mandible.
6. Ghafari et al 1998 suggested that headgear produces some maxillary
restraint and the Fränkel, mandibular growth increase.compliance
HG failure rate 5% for female and 25% for male (Ghafari 1998)
, Mohammed Al-Muzian, University of Glasgow, 2013
32
Intrusion of anterior teeth but less efficient than TADs (Degushi, 2008)
Hickman (1974) - devised a headgear which will accept 2 or even 3 "J"
hooks each side.
Root resorption. Linge and Linge 1983
Results in more movement on the side with the longer outer bow according
to Castagliano's Theorum
High-pull headgear at night, directed above the center of rotation of the
molar, acts to distalise the root and hold the movement achieved during
the day time by the URA, (Cetlin & Ten Hoeve, 1983).
Extraction of the upper second molars may be required bow and this claimed
to achieve 6mm molar distalisation (Orton, 1996).
Headgear to upper part of the Twin block , Park 2001used TB with HG and
torqueing spring and compared it to conventional TB and found that better
control of ULS inclination was with the first gp.
In a study by Wise et al (1994) which compared 20 non-extraction patients
in which a transpalatal bar was used for at least 5 months with similar
patients in whom it was not used, no significant differences were found
between the two groups.
Not all patients are honest in actual compliance. Using time charts can
increase co-operation (Cureton et al. 1992, 1993).
Contact dermatitis-type IV delayed hypersensitivity immune response
(Rahilly and Price, 2003).
Four Types of Headgear Injuries in Europe, Samuels 1993 (23 countries
studied)
Ideal physical properties for the HG safety mechanism according to the
study of Stafford on 1998
Force affecting factors, Bowden 1978
Cureton et al. (1993) recommend the use of headgear charts routinely.
Recently the monitoring device like the Affirm headgear traction module has
, Mohammed Al-Muzian, University of Glasgow, 2013
33
been used (electronic timer)
Timing
1. Dental age: McNamara (1987) suggested that the optimal time for treatment
is in the early late mixed dentition, coincident with the eruption of the upper
permanent incisors.
2. Skeletal age: Baccetti et al (1998) showed that the early treatment group
CVM2 showed effective forward displacement of the maxillary structures
whereas the late treatment group CVM3 showed no change compared with
controls
3. Chronological age: Other investigators have suggested that for optimal
orthopaedic effects, treatment should be initiated before the patient is 9 years
old ( Proffit, 2000).
4. Kim et al., 1999, meta-analysis of effectiveness of protraction HG concluded
it was less effective on patients >10yrs
Evidence based short term effectiveness of PH, Mandall, 2010 (similar to
study of Ngan 1998)
Evidence based long term effectiveness of PH, Mandal 2012: Masucci 2011:
a removable full coverage acrylic splint is used with a protraction headgear
(Proffit 1986).
McNamara (1987) has described the use of a Biocryl and wire splint that is
bonded in the mouth.
Major (2012) in Canada, he found Approximately 3 mm of horizontal A-
point movement is predictably attainable with the skeletal one in comparison
to dental one
Rapid maxillary expansion Advantages (Haas 1973).
Many clinicians use protraction with a facemask following or
simultaneously with palatal expansion, because some evidence suggests that
the expansion makes antero-posterior skeletal change more likely. Kim et al
, Mohammed Al-Muzian, University of Glasgow, 2013
34
(1999)
There is other evidence that the expansion is optional and should be dictated
by the maxillary arch width related to the lower arch width, Vaughan 2005.
Ishii et al (1987) describe the effects of providing the protraction force from
the first molars or the premolar region. Protraction from the first molars
results in more anterior movement and a forward and upward rotation of the
maxilla; protraction from the premolars results in less forward movement
but less tendency to upward and forward rotation.
The idea of this appliance is that because the condyle is a growth site, the
growth impeded by extra-oral force (Graber, 1977).
Despite success in animal experiments, most human studies have found little
difference in mandibular dimensions between treated and untreated subjects
(Sugawara et al, 1990).
The effects of chincup therapy , (Thilander 1963)
Reverse chin cup therapy, Developed in Germany in 2012 by Rahman 2012
show similar result when the reverse chin cup therapy compared to face
mask therapy in RCT involving 42 samples at age of 8-9 year.
References
1. VLE, National orthodontic Programm
2. Excellence in Orthodontics
3. Postgraduate notes in orthodontics, 5th edition
4. Van Beek H. – Combination Headgear-Activator – JCO, March 1984.
5. Van Beek H. – Overjet Correction by a Combined Headgear and Activator –
EJO,4(1982) 279-290.
6. Orton H.S. – Functional Appliances in Orthodontic Treatment – An atlas of
clinical prescrption and laboratory construction – Quintessence Books, 1990.
, Mohammed Al-Muzian, University of Glasgow, 2013
35
7. Skeletal effects of early treatment of Class III malocclusions with maxillary
expansion and face-mask therapy Baccetti T et al (1998) AJODO 113: 333 –
343
8. The early management of Class III malocclusions using protraction headgear
Marcey-Dare LV (2000) Dental Update 27(10): 508-13
9. Biomechanical and clinical considerations of a modified protraction headgear
Nanda R (1980) AJO 78: 125 – 139
10.The management of Class III and Class III tendency malocclusions using
headgear to the mandibular dentition Orton HS (1983) BJO 10: 2 – 12
11.A philosophy of combined orthopedic-orthodontic treatment PfeifferJP &
Grobety D (1982) AJO 81: 185 – 201
12.Protraction of the cleft maxilla Ranta R (1988) EJO 10: 215 – 222
13.Bioprogressive therapy Ricketts et al (1979) Section 1 Part 5:Orthopaedics in
Bioprogressive therapy and Section 7 Part 7: Factors in headgear design and
application
14.Chin cup therapy for mandibular prognathism Graber LW (1977) AJO 72: 23 –
41.
15.The management of Class III and Class III tendency malocclusions using
headgear to the mandibular dentition Orton HS (1983) BJO 10: 2 – 12.
16.Effects of chin cup force on the timing and amount of mandibular growth
associated with Class III malocclusion Mitani et al (1986) AJO 90: 454 – 463.
17.Stability of changes associated with chin cup therapy Deguchi et al (1996)
Angle O 66: 139 – 145.
18.A Randomised linical Trial, Tulloch JFC, Phillips C, Koch and Proffit WR.
AJODO 1997; 111: 391-400
19.BOS advices,
http://www.bos.org.uk/OneStopCMS/Core/CrawlerResourceServer.aspx
, Mohammed Al-Muzian, University of Glasgow, 2013
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20.Contemporary orthodontics, Fourth Edition, 2007
, Mohammed Al-Muzian, University of Glasgow, 2013