4. • Class II malocclusion is one of the most common orthodontic problems and it occurs in about one-third of
population.
• Class II malocclusion can result from many contributing factors, both dental and skeletal. Although
maxillary protrusion and mandibular retrusion are both found to be possible causative factors.
• For class II patients in whom the mandible is retrognathic, the ideal treatment is to alter the amount or
direction of growth of mandible. Functional appliances include removable and fixed devices that are
designed to alter the position of the mandible, both sagittally and vertically and to induce supplementary
lengthening of the mandible by stimulating increased growth at the condylar cartilage.
Kaur S, Soni S, PrasharA, Bansal N, Brar JS, Kaur M. Functional appliances. Indian J Dent Sci 2017;9:276-81.
INTRODUCTION
5. • Definition :A Myofunctional appliance is defined as a loose fitting or passive appliance
which harnesses the natural forces of the orofacial musculature that are transmitted to
the teeth & alveolar bone in a predetermined direction through the medium of the appliance.
• Proffitt – A “ Functional appliance is one that changes the posture of the mandible, and causes the
patient to hold it open and/or forward for Class II correction or back or open for Class III correction,
the pressures created by the stretch of the muscles & soft-tissues are transmitted to the dental &
skeletal structures, moving teeth & modifying growth.”
• Moyers – “ Loose removable appliances designed to alter the neuromuscular environment of the
orofacial region to improve occlusal development &/or craniofacial skeletal growth.”
Bishara SE, Ziaja RR. Functional appliances: a review. Am J Orthod Dentofac Orthop . 1989;95(3):250-8.
6. • GRABER’S CLASSIFICATION:
GraberTM.The use of muscle forces by simple orthodontic appliances.Am J Orthod. 1979;76(1):1-20.
Group I
• Transmit muscle force directly to the teeth.
• Ex: Inclined planes and oral shields or screens.
Group II
• Reposition the mandible downward and forward activating the attached and
associated musculature.
• Ex. Original activator & modifications. Such appliances are usually one-
piece(Monobloc)
Group III
• Relies on Mandibular positional changes – by operating through the vestibule,
outside dental arches
• Ex. Frankel Function Regulator combining the Oral-screen like shields and
activator like guidance and muscle stimulation.
7. Proffit and Fields classification:
1.passive tooth-borne appliances:
• The largest category, passive tooth-borne appliances, includes monobloc, activator, bionator,
Bimler, and Twin-block.
• They do not have intrinsic force generating capacity(Screws).
2. Active tooth-borne appliances
• Include expansion screws/springs to move teeth
• Ex: Activator & modifications bearing active components.
3.Tissue-borne appliances
• Located in vestibule and free of contact with bone/teeth
• Ex. Function Regulator, oral screen.
Wahl N. Orthodontics in 3 millennia. Chapter 9: functional appliances to midcentury.Am J Orthod Dentofacial Orthop.
2006;129:829-33.
8. I. MYODYNAMIC:
• In the myodynamic approach a small amount of forward posturing (mandible postured forward 5-
to 6-mm and opened 2- to 3-mm beyond the rest position) stretches the muscle fibers and
stimulates their continued contraction, which in turn brings the mandible back into the rest
position.
• Ex. Elastic open Activator, Bimler appliance
II. MYOTONIC:
• In the myotonic approach the mandible is postured forward or opened vertically by a much
greater amount. The muscles and soft tissues are stretched to a greater degree than with
myodynamic appliances (mouth opening 8- to 10-mm or more beyond the rest position) so that
the inherent elasticity of the tissues will create traction on the mandible.
• Ex. Harvold woodside Activator
Hägg U,Wong RW. Strategies forTreatment of Adolescent Patients with Class II Malocclusions. In Esthetics and
Biomechanics in orthodontics. WB Saunders. 2015.pp. 197-204.
9. According to the force produced:
Jasper JJ, McNamara Jr JA.The correction of interarch malocclusions using a fixed force module. Am J Orthod Dentofac
Orthop. 1995;108(6):641-50.
Appliances producing pushing force:
The use of these appliances typically results
in a change in the postural level of muscle
activity and will, in most instances, result in a
change in mandibular posture.
a) Temporarily fixed functional appliances
Twin block.
b) Permanently fixed functional appliances.
Herbst appliance
Jasper jumper
Appliances producing pull force
Ex. Class II elastics and
Severable Adjustable Intermaxillary Force
(SAIF) spring developed by Armstrong in
1957.
10. A. REMOVABLE FUNCTIONALAPPLIANCES :
• Activator, Frankel, Bionator,
B. FIXED FUNCTIONAL APPLIANCES:
• Class II correction appliances are divided into two categories depending on their mode of action
and type of anchorage; which include
(1) Intermaxillary noncompliance appliances and
(2) Intramaxillary noncompliance appliances.
• Papadopoulos, further classified intermaxillary noncompliance appliances into four categories;
depending upon features of force system used to advance the mandible; which include:
• (A) Rigid Intermaxillary Appliances (RIMA) (C) Hybrid appliances (combination)
• (B) Flexible Intermaxillay Appliances (FIMA) (D) Appliances acting as substitute for elastics.
Singh DP, Kaur R. Fixed functional Appliances in Orthodontics-A review. J Oral Health Craniofac Sci. 2018; 3: 001-010.
12. Hybrid Appliances (Combination of RIMA and FIMA) are
as follows:
• Eureka Spring™
• Forsus™Fatigue-Resistant Device
• Twin Force Bite Corrector (TFBC)
Appliances Acting as Substitutes for Elastics includes:
• Calibrated Force Module
• Alpern Class II Closers
13. BIOLOGICAL COMPONENTS INVOLVED IN THE MODE OF ACTION OF
FUNCTIONAL APPLIANCES
a. Condyle
b. Articular disc
&
Retrodiscal pad
c. Glenoid fossa
TMJ
a. Condyle
b. Articular disc
&
Retrodiscal pad
c. Glenoid fossa
Masticatory Muscles
Mainly
Lateral pterygoid
muscle
14. Condyle:
• Condylar process is ovoid seated atop a narrow mandibular neck. It is 15 to 20 mm side to
side and 8 to 10 mm from front to back.
• Condyle comes under secondary cartilage variety.
Primary Vs Secondary Cartilage:
• According to Stutzmann (1976)
• Primary Cartilage – exists in the axial skeleton, skull base and limbs; the dividing cells , the
differentiated chondroblasts are surrounded by a cartilaginous matrix that isolates them from
local factors able to restrain or stimulate cartilaginous growth.
• Secondary Cartilage – exist in the condylar and coronoid processes and sometimes in sutures;
the dividing cells, prechondroblasts, are not surrounded by a cartilaginous matrix and thus are
not isolated from local growth modifications
15. The zone of growth includes
a. skeletoblasts &
b. prechondroblasts, cells that
divide but do not synthesize a
cartilaginous matrix as seen in
primary cartilage.
SO LOCALLY EXTRINSIC
FACTORS MAY MODIFY THE
GROWTH RATE OF CONDYLAR
CARTILAGE.
16. lateral pterygoid muscle & retrodiscal pad:
Lateral pterygoid muscle: Retrodiscal pad:
Protrusion of the lower jaw
Depression the lower jaw
Unilateral movement of the lower jaw
The disk is attached posteriorly to a region of
loose connective tissue that is highly
vascularised and innervated known as
retrodiscal tissue.
17. Increased contractile activity of Lateral pterygoid muscle
Increased of the repetitive activity of retrodiscal pad
Condylar growth & remodeling
GLENOID FOSSA:
When the condyles are brought into a
new forward and downward position by
the functional appliances glenoid fossa
remodels and adapts to the new
condylar position.
18. • Basic steps involved in the mode of operation of functional appliances functional appliance :
Functional appliance
Increased contractile activity of the LPM
Intensification of the repetitive activity of the retrodiscal pad (bilaminar zone)
Increase in growth-stimulating factors (growth hormone)
- Change in condylar trabecular orientation
- Additional growth of condylar cartilage
-Additional subperiosteal ossification of the posterior border of the mandible
Supplementary lenghthening of the mandible
19. Principles of functional appliances
PRINCIPLES
FORCE APPLICATION
Compressive stress & strain
transmitted directly or indirectly
to structures involved.. resulting
in a primary alteration in form
with a secondary adaptation in
function.
FORCE ELIMINATION
Abnormal & restrictive
environmental influences
eliminated and therefore aids in
normal development
Primary effect – rehabilitation of
function
Secondary effect – adaptation of
form according to function.
20. Myotactic reflex
• It is also called as Liddell-Sherrington reflex, muscular reflex, and stretch reflex.
• It is the tonic contraction of the muscles in response to a stretching force, due to stimulation of
muscle proprioceptors.
• The stretch reflex requires sensory neurons that supply muscle spindles and motor neurons
that supply the extrafusal fibres of the muscle.
Mechanism of stretch reflex:
• Muscle spindles are located within the muscle itself and it is made up of 2 to 15 thin intrafusal
fibers.
• The slender ends of the intrafusal fibers are striated and contractile while the central or nuclear
bag is noncontractile.
21. • These sensory nerve fibers synapse with the
motor neuron known as alpha efferents that
supplies the extrafusal muscle fibers
responsible for the contraction of the
stretched muscle.
• Activation of the gamma efferents will
cause polar contraction of the intrafusal
fibers and therefore puts the noncontractile
nuclear bag under tension.
• This causes a mechanical distortion which is
similar to passive stretch of the muscle.
• Through these gamma efferents, the higher
centers of the brain via reticular formation
influence the stretch or myotatic reflex.
22. Clasp knife reflex
• Clasp knife reflex is also called as autogenic inhibition or inverse myotatic reflex.
Mechanism:
• The excessive or rapid stretch of the muscle brings in to play some inference that annuls the
stretch reflex and allows the muscle to be lengthened with little or no tonic resistance.
• Thus, the stimulus necessary to elicit the clasp knife reflex is excessive stretch and when
elicited, it inhibits muscular contraction, thus causing the muscle to relax.
• The receptors for the clasp knife reflex are the Golgi tendon organs located in the tendon of the
muscle.
23. • It is a di-synaptic reflex arc because an
interneuron is interposed between the sensory
neuron and the motor neuron.
• The motor neurons supplying the stretched
muscles are bombarded by impulses delivered
over two competing pathways, one facilitating
and other, inhibiting muscle contraction. The
output of the motor neuron poll depends upon
the balance between the two antagonists
inputs.
• The functional significance of the clasp knife
reflex is to protect the overload by preventing
damaging contraction against strong
stretching forces.
24. MONOBLOC
• The first practitioner to use functional jaw orthopedics to treat a malocclusion was Pierre Robin
(1902). His appliance influenced muscular activity by changing the spatial relationship of the
jaws.
• Robin designed his monobloc specifically for children with the glossoptosis syndrome
(ectomorphic constitution, adenoid facies, mouth breathing, high palate, and other problems). It
has since been named the Pierre Robin syndrome.
• It extended all along the lingual surfaces of the mandibular teeth, but it had sharp lingual imprints
of the crown surfaces of both maxillary and mandibular teeth. It incorporated an expansion screw
in the palate to expand the dental arches.
Wahl N. Orthodontics in 3 millennia. Chapter 9: functional appliances to midcentury.Am J Orthod Dentofacial Orthop.
2006;129:829-33.
26. History
• Kingsley introduced "Jumping of the bite": in 1879 to correct sagittal relationship between Upper
and lower jaws.
• Hotz modified the kingsley's plate into a vorbissplate (used it for deep bite and retrognathism).
• Alfred P. Rogers
• “ Father of myofunctional therapy”
• First to implicate the facial muscles for the growth, development and form of the
stomatognathic system.
• Pierre Robin - 1902 – “The Monobloc”
• From Kingsley's concept, VIGGO ANDRESEN 1908 developed a loose fitting appliance on his
daughter as a retainer during summer vacations which gave remarkable results.
• He called it BIOMECHANICAL RETAINER.
Wahl N. Orthodontics in 3 millennia. Chapter 9: functional appliances to midcentury.Am J Orthod Dentofacial Orthop.
2006;129:829-33.
27. • The original Andresen activator was a tooth-borne, loosely fitting passive appliance
consisting of a block of plastic covering the palate and the teeth of both arches,
designed to advance the mandible several millimeters for Class II correction and open
the bite 3 to 4 mm.
• The original design had facets incorporated into the body of the appliance to direct
erupting posterior teeth mesially or distally, so, despite the simple design, dental
relationships in all 3 planes of space could be changed.
28. • Andresen moved to Oslo University, Norway where he met KARL HAUPL (a periodontist
and histologist) who became convinced that appliance induced growth changes in a
physiological manner. Then the name Norwegian appliance.
• Later as the appliance acts by activating the muscles it was then called finally as ‘
ACTIVATOR.’
• It activates the masticatory, facial, lip, and tongue musculature.
Carels C,Van der Linden FP. Concepts on functional appliances' mode of action. Am J Orthod Dentofac Orthop.
1987;92(2):162-8.
29. Andersen Haupl concept-Mode of action
• The construction bite does not open the mandible beyond the rest position (less than 4mm).
• Presence of a loose fitting appliance Increases frequency of reflex contractions in the
muscles of mastication+ increased swallowing frequent biting into the appliance
Mandible moves and engages the appliance
Thus activator rely mainly on the muscle activity during biting & swallowing & thus works by using
KINETIC ENERGY.
Myotactic reflex actively and Isometric muscle contraction
Stimulate the LPM & retrodiscal pad thus
bring about bone remodelling and condylar
adaptation.
These muscle contraction forces are
transmitted by the appliance and moves the
teeth
30. • The muscular forces generated by the forward mandibular positioning were transferred to the
maxillary and mandibular teeth through the acrylic body and the labial bow, which contacted the
maxillary incisors.
• In theory these forces were transmitted through the teeth onto the periosteum and bone, where
they produced a restraining effect on the forward growth of the maxilla, while stimulating
mandibular growth and causing maxillary-mandibular dentoalveolar adaptations.
Bishara SE, Ziaja RR. Functional appliances: a review. Am J Orthod Dentofac Orthop. 1989;95(3):250-8.
31. Guidance of Eruption:
• Using the Andresen appliance, tooth eruption is guided by facets cut into the lingual acrylic.
In the upper arch the acrylic contacts the posterior
teeth on their mesiopalatal aspects, with flutes sloping
distally so that the teeth erupt distally.
The lower posterior teeth contact acrylic on their
distolingual aspect, with flutes sloping mesially to
encourage their mesial eruption.
32. Retrusion of Incisors:
• Acrylic is trimmed at the palatal surface
of the incisors.
• The labial bow is activated.
Incisors can be protruded by loading their lingual surface
and screening lip strain by passive labial bow.
1) Entire lingual surface loaded
2) Incisal third of lingual surface is loaded.
Protrusion of Incisors
33. Intrusion Extrusion
• The lingual acrylic can also be trimmed to encourage buccal
expansion.
• More effective expansion can be achieved using Jack screws.
34. Criticism about andresen & haupl concept
• Ahlgren claimed that only daytime use of the activator stimulates the protractors and that during
the night its stimulation effect disappears. Activator is mainly a night time wear appliance.
• The appliance would thus become effective during daytime with the contraction of the protracting
masticatory muscles.
• During sleep the frequency of biting & Swallowing decreases and also the freeway space is almost
double what it is when the patient is awake.
• This reduces the myotactic reflex activity & muscle contraction.
35. HEREN, HARVOLD & WOODSIDE CONCEPT
• Do not accept the theory that myotactic reflex activity with isometric contractions induce skeletal
adaptation.
• Mandible drops open when the patient is asleep-conventional activator becomes ineffective:
1.either the appliance falls out or is not able to advance the mandible
2.amount of actual muscle contraction possible when the patient is asleep is questionable.
• Concept: When the mandible is opened beyond 4mm it acts by stretching of soft tissue - THE
VISCO ELASTIC EFFECT.
• Stimulus is EXCESS STRETCH when elicited leads to muscle relaxation.
• CLASP - KNIFE REFLEX .
36. • Viscoelastic properties of muscles and the stretching of the soft tissues-decisive for Woodside
activator action.
• Bite is opened approximately 10-15mm beyond the postural rest position
• It induces stretching of soft tissues & the viscoelastic pull of the soft tissues are responsible for
the appliance action.
• The power to produce alveolar remodeling is obtained from inherent elasticity of muscle,
tendinous tissues & skin. Thus the appliance works by POTENTIAL ENERGY rather than
kinetic energy.
37. • Herren's activator (1953)
• Herren's shage activator – LSU activator
• The bow activator of Schwarz
• Reduced activator of Cybernator of Schmuth
• Eschler's modification
• The Karwetsky appliance
• The propulsor
• The cutout (or) palate free activator
• Elastic open activator of Klammt
• Stockfish's Kinetor
38. Studies
Williams S, Melsen B. Condylar development and mandibular rotation and displacement during activator treatment: an
implant study. Am J Orthod. 1982;81(4):322-6.
39. • An analysis of the effects of activator treatment on the spatial development of the
mandible over 11 months was performed via the metal implant method for a group of
nineteen patients.
• This study indicates that the induction of a condylar growth pattern in an
upward/posterior direction will result in a center of mandibular rotation that is
favorable for sagittal changes.
• The present study revealed that the type of activator used was not able to completely
control the development in height of the maxilla.
40. • It would, therefore, seem reasonable to increase the vertical control, either through an
increase in height of the construction bite as suggested by Woodside’” or by
combining the activator with a high-pull headgear as recommended by Teuscher.‘
• As a conclusion of the present study, it could be stated that a posterior/upward growth
direction of the condyle combined with an anterior rotation of the mandible is the
optimal development which can improve a sagittal discrepancy in treatment of basal
Class II cases.
41. Vargervik K, Harvold EP. Response to activator treatment in Class II malocclusions.Am J Orthod. 1985 ;88(3):242-51.
42. • A clinical study was designed to disclose the effects of activator treatment in the correction of
Class II malocclusions.
• The study extended over a 7-year period and originally included 120 children-56 girls and 64 boys.
The only selection criteria were a Class 11 malocclusion in the mixed dentition stage.
• Treatment was completed in 83 of the subjects; 51 of these were treated with activators only. The
remaining 31 required fixed appliance treatment subsequent to the activator treatment.
• The mean age at start of treatment was 10 years. The mean activator treatment time was 35 months
for the boys and 31 months for the girls.
43. • Conclusion: Treatment of Class II malocclusions in growing patients by means of an activator
resulted in (1) correction of Class II molar relationship, (2) correction of overjet, (3) leveling of
mandibular occlusal plane, (4) uprighting of maxillary incisors, (5) reduced advancement of
the maxilla, (6) increased advancement of all mandibular structures, (7) increased face profile
angle, and (8) increased lower face height.
• The treatment responses that resulted in the changes in dental arch relationship included
reduced forward growth of the maxilla and anterior relocation of the glenoid fossae.
44. Stavridi R, Ahlgren J. Muscle response to the oral-screen activator. An EMG study of the masseter, buccinator, and mentalis
muscles.Eur J Orthod. 1992;14(5):339-49.
45. • Study examined electromyographically the response of the masseter, buccinator and
mentalis muscles to the oral-screen activator (OSAC), which is a conventional activator
constructed with buccal shields and lip pads.
• The material consisted of 10 children, with Angle Class II,
division 1 malocclusion and narrow dental arches (mean age 10.7
years).
• The group had a mean overjet of 8.5 mm, and a mean ANB angle
of 6 degrees. The construction bite of the OSAC was taken with
the anterior teeth in edge-to-edge position.
46. • The recording procedure included the following positions: (a) postural position of the mandible
with lips relaxed and lips closed; (b) clenching; (c) swallowing saliva; and (d) spatula exercise.
• EMG recordings were made after 1, 2, and 3 months of appliance treatment.
• Conclusion: Masseter activity is stimulated and mentalis hyperactivity is reduced during
swallowing. Masseter activity is unaffected during clenching.
• Lip pads do not reduce mentalis hyperactivity during lip seal. On the contrary, it increases
significantly.
• Buccal shields do not affect the buccinator EMG.
47. Ball JV, Hunt NP.The effect of Andresen, Harvold, and Begg treatment on overbite and molar eruption. Eur J Orthod.
1991;13(1):53-8.
48. • A retrospective cephalometric study was carried out to compare the vertical dental changes
between patients treated with the Andresen (30), Harvold (19), or Begg (30) appliances, and
an untreated control group (24).
• Conclusion: All three appliances successfully reduced the overbite although the reduction
tended to be more stable with the functional appliances.
• Overbite was reduced by a combination of factors which varied according to the appliance
used, but included lower incisor intrusion or restraint, molar eruption, vertical growth of the
face and lower incisor proclination in the functional groups.
49. Remmer KR, Mamandras AH, Hunter WS,Way DC. Cephalometric changes associated with treatment using the activator,
the Fränkel appliance, and the fixed appliance.Am J Orthod. 1985 Nov 1;88(5):363-72.
50. • Among the three groups, the activator sample showed the most anterior movement of the
mandible (2.3 mm); the fixed group showed the least (0.6 mm).
• The fixed appliance group showed more posterior rotation of the mandible than the
activator group.
• However, relative to cranial base, the movement of the mandibular symphysis was not
statistically different in the three groups. There were little differences among the
treatment groups with regard to changes in the soft-tissue profile.
• In clinical terms, there was a remarkable similarity in the changes that occurred in the
three treatment groups.
51. Baltromejus S, Ruf S, Pancherz H. Effective temporomandibular joint growth and chin position changes: Activator
versus Herbst treatment. A cephalometric roentgenographic study. Eur J Orthod. 2002;24(6):627-37.
52. • Activator treatment-40 patients, herbst treatment-98,..class 2 div 1 ,…
• Cephalometric measurements were performed.
• Conclusion: TMJ-changes were vertical and anterior in the activator group, predominantly
posterior in herbst group.
• Chin: Treatment effects for the herbst group exceeded activator group both caudally and
anteriorly.
• Activator-anterior rotation,.. Herbst –Posterior rotation.
• Herbst appliance renders more favourable sagittally oriented treatment effects in much shorter
period of time compared to activator.
10.3 age 12.6 age
53. Varlık SK, Gültan A,Tümer N. Comparison of the effects ofTwin Block and activator treatment on the soft tissue
profile.Eur J Orthod. 2008 ;30(2):128-34.
54. • Growing Class II division 1 patients revealed significant profile changes after TB and
activator treatment.
• The most pronounced effects of both appliances were forward movement of mandibular
soft and hard tissue landmarks. The effects of activator and TB treatment on the soft
tissue profile were similar.
• Longitudinal studies are required to evaluate the stability of the observed soft tissue
changes.
55. Ulusoy Ç, Darendeliler N. Effects of Class II activator and Class II activator high-pull headgear combination on the mandible:
a 3-dimensional finite element stress analysis study.Am J Orthod Dentofac Orthop. 2008;133(4):490-e9.
56. • In this study, the stress distribution in the whole mandible was determined.
1. The mandibular body was subjected to higher stresses than the condylar region.
2. The maximum stress values were obtained in the muscle attachment regions.
3. The medial side and the top of the coronoid process were the most stressed regions.
• The Class II activator and the Class II activator high-pull HG combination have different
effects on the total maxillofacial complex, but, in this study, these appliances’ effects on
the mandible were evaluated. Both appliances can cause morphologic changes in the
mandible by activating the masticatory muscles to change the growth direction of the
mandible.
57. Idris G, Hajeer MY, Al-Jundi A. Soft-and hard-tissue changes following treatment of Class II division 1 malocclusion with
Activator versusTrainer: a randomized controlled trial. Eur J Orthod. 2019;41(1):21-8.
58. • 12 months of Class II division 1 treatment in growing patients with a
conventional functional appliance (a modified Activator) versus a
myofunctional Trainer system (T4K®).
• Activator group (10.6 ± 1.3 years); the T4K® group
(10.3 ± 1.4 years). Skeletal, dentoalveolar, and soft tissues changes
were assessed using standardized lateral cephalograms collected
before and after 12 months of treatment.
Conclusion: Significant decrease in the skeletal angle ANB with
Activator compared to Trainer. a significant greater increase in the
facial convexity angle with Activator and a significant reduction in the
overjet.
Activator was more effective than the T4K® in treating Class II
division 1 growing patients.
60. BIONATOR
• Balters developed the original appliance in the early 1950s.
• It is the prototype of a less bulky appliance.
• Its lower portion is narrow; upper part has only lateral extensions, with a crosspalatal stabilizing
bar. The palate is free for proprioceptive contact with tongue and the buccinator wire loops hold
away the potentially deforming muscular action.
• According to Balters, the equilibrium between the tongue and circumoral muscles is
responsible for the shape of the dental arches and for the intercuspation, and the functional space
for the tongue are essential to the normal development of the orofacial systems.
61. MODE OF ACTION
• The principle of treatment with the bionator is not to activate the muscles but to modulate
muscle activity thereby enhancing normal development of the inherent growth pattern and
eliminating abnormal and potentially deforming environmental factors.
• The bite cannot be opened and must be positioned in an edge to edge relationship.
• Balters reasoned that a high construction bite could impair tongue function and the patient
can actually acquire a tongue thrust habit as the mandible dropped open and the tongue
instinctively moved forward to maintain an open airway.
62. THE APPLIANCE DOES THE FOLLOWING ACTIONS:
• Due to sagittal repositioning of mandible, the appliance increases the oral functional space. This
appliance induces myotactic reflex activity with isotonic muscle contraction.
• The appliance exerts a constant influence on the tongue by means of palatal arch which promotes
anterior positioning of tongue. The appliance prevents the external unfavourable muscle forces by
means of vestibular arch and its buccal extension.
• Intrusion and extrusion of teeth can be achieved by loading or unloading the teeth with acrylic.
• Bionator therapy resulted in forward movement of point B, and increased SNB angle.
• Bionator appliance corrects molar relationship and overjet of class II patients mostly by dentoalveolar
changes.
63. • The Bionator is an effective appliance for treating functional or mild skeletal Class II
malocclusions in the mixed and transitional dentitions.
• Patient compliance is excellent for both day time and night time wear.
64. • Jing (1997) used bionator headgear combination in growing patients with class 2 div 1
malocclusion and concluded that SNA and ANB angle was reduced; SNB angle was
significantly increased.
• BHC appliance not only restrained the horizontal maxillary development but also effectively
promotes the forward mandibular growth, which obviously improved the mandibular
retrognathism.
• The long-term stability and recurrence of BHC appliance therapy in the treatment of
malocclusion needs to be further studied.
Jing M, Hong Z.The correction of class II, division 1 malocclusion with bionator headgear combination appliance. Journal of
Tongji Medical University. 1997 Dec 1;17(4):254-6.
65. Jena AK, Duggal R, Parkash H. Skeletal and dentoalveolar effects ofTwin-block and bionator appliances in the treatment of
Class II malocclusion: a comparative study.Am J Orthod Dentofac Orthop. 2006;130(5):594-602.
66. • pitchfork analysis is used in the study to measure physical movement of the maxillary and mandibular
molars and incisors relative to their dental bases, as well as the displacement of the maxilla and
mandible relative to the cranial base.
• Conclusion: Neither appliance was efficient in restricting forward growth of the maxilla.
• Both appliances increased mandibular growth, but the Twin-block induced more mandibular growth
than the bionator. Both appliances helped dramatically in molar correction, and the Twin-block
corrected the molar relationship more efficiently than the bionator, The Twin-block and bionator
appliances caused significant forward movement of the mandibular incisors.
• Both appliances were effective for overjet reduction in Class II Division 1 malocclusion patients, but the
Twin-block appliance was better than the bionator.
67. • Neves (2014) compared bionator and jasper jumper followed by fixed appliance concluded the
following:
• A restrictive effect on the maxilla; Retrusion and extrusion of the maxillary incisors;
• Labial tipping and protrusion of the mandibular incisors in both groups and intrusion with the Jasper
Jumper appliance;
• Maxillary molar distalization with the Jasper Jumper; Extrusion and mesialization of the mandibular
molars;
• Both appliances provided significant improvement of maxillomandibular relationship, overjet,
overbite and molar relationship. Treatment with the Jasper Jumper was shorter than with the Bionator.
Neves LS, Janson G, Cançado RH, de Lima KJ, FernandesTM, Henriques JF.Treatment effects of the Jasper Jumper and the
Bionator associated with fixed appliances. Progress in orthodontics. 2014 Dec 1;15(1):54.
69. Frankel’s functional regulator
Mode of action: vestibular arena of operation
• Rolf Fränkel (1908-2001) must be recognized as the inventor of an appliance that corrects malocclusions
with little or no contact with the dentition.
• The functional regulator (FR) is designed to be an exercise device.
• According to Frankel, the dentition is influenced by peri-oral muscle function.
• Abnormal peri-oral muscle function creates a barrier for the optimal growth of the dento- alveolar
complex.
• He believes that the correction of a Class II malocclusion is achieved by permanently advancing the
position of the mandible through muscular exercise.
Bishara SE, Ziaja RR. Functional appliances: a review. Am J Orthod Dentofac Orthop . 1989;95(3):250-8.
71. Design and rationale:
• Since the FR is to a great extent a tissue-borne appliance, it facilitates active muscular training. It
attempts to strengthen the mandibular protractors by advancing the mandible in a slow, stepwise
fashion during a long period of time. Frankel advocates advancing the mandible 2 to 3 mm every 4
to 5 months.
• The muscles are allowed to adapt to each new mandibular position before further advancement is
performed.
• Frankel believes that the 2 to 3 mm incremental advancement will decrease the risk of muscular
fatigue and that each new forward position of the mandible results in renewed growth stimulation
of the condyle.
72. • Another feature of the FR is its ability to facilitate maxillary arch width expansion.
• The expansion is believed to be the result of two mechanisms: (1) the buccal and labial shields
relieve the muscle pressure on the teeth causing the crowns to tip buccally; (2) the buccal shields
are positioned to the maximum depth of the vestibule, thus producing an outward pull on the
periosteal tissue.
• This force is transmitted through the muscle fibers and connective tissue onto the alveolar bone
where it induces lateral movement of the alveolus.
• This movement is supposed to counteract the lingual root movement so that a bodily buccal tooth
movement is produced. It is suggested that for this expansion to be stable, treatment should be
initiated in the mixed dentition.
73. Sagittal correction via tooth bone maxillary anchorage
• The appliance is anchored on the maxillary dentition both in the molar and canine region. And
there is no tooth contact in the lower arch.
• The mandible is positioned anteriorly by means of a lingual contact more of a proprioceptive
trigger for postural maintenance than a pressure bearing area.
• Differential eruption guidance: The maxillary teeth are withheld whereas the mandibular teeth
are free to erupt upwards and forwards. This not only corrects vertical dimension but also helps in
the sagittal correction of Cl-II malocclusion.
• Minimal maxillary basal effect: Relatively little retrusive sagittal effect is seen on the maxilla in
contrast to the significant forward change of the mandible. It is possible to activate the maxillary
labial wire to close spaces.
74. Buccal shield lip pads and periosteal pull:
• There will be outward periosteal pull by maximal extension of the shield and pads into
the depth of the buccal and labial vestibule to the point at which the depth of the sulcus is
under tension.
• This cause an outward growth of membranous bone, plus relief of any restrictive changes
in the posterior segments and bone formation at the apical base.
75. Classification of FR:
• FR1 Types a , b and c
Frankel-Ia is used for class I malocclusion where there is minor to moderate
crowding and also in cl-I deep bite cases.
Frankel-Ib is used for class II, division 1 malocclusion where overjet does not
exceed 5mm. Frankel-Ib is quite similar to 1a, the difference being the use of a
lingual acrylic pad instead of lingual wire loops to contact the lingual mucosa
of the lower incisor segment.
Frankel 1 b
Frankel-Ic differ from Frankel-Ib in that
the buccal shields are split horizontally and
vertically into two parts permitting the
movement of the free position in a forward
direction by pulling the anterior section
forward.
76. Frankel-III: Here the lip pads are situated in the maxillary,
instead of mandibular vestibular labial sulcus. Labial bow rests
against the mandibular teeth and not on the maxillary incisors.
There is a protrusive bow similar to that of Frankel-II behind the
upper incisors to stimulate the forward movement of these teeth.
FR 2: Frankel-II is modified by adding a stainless steel
protrusion bow behind the maxillary incisors, which serves
to maintain the pre-functional appliance alignment that was
achieved and stabilize the appliance by helping to lock it on
the maxillary arch.
77. • Frankel-IV: Primarily used in correction of open bite. In open bite cases, Frankel-IV redirect the
mandibular growth from a downward and backward growth rotation to a upper and forward
rotation.
• With lip seal exercises, lip contact takes over, reducing tongue protrusion and causing tongue to
move back into its normally raised position.
78.
79. • Owen (1981) study on FR appliance- there are four potential changes made by the Frankel
appliance: (1) increased mandibular growth, (2) maxillary retraction, (3) dentoalveolar
changes, and (4) lateral expansion.
• Kerr (1981) used FR on cleft palate patients and concluded primary expansion of collapsed
maxillary segments to correct the crossbite or improve the maxillary width is not possible with
FR.
• A significant amount of accommodation to the appliance occurs within 1 week after insertion,
but maximum improvement in speech intelligibility occurs with full-time wear of the appliance
for as many hours per day as possible.
Owen AH. Morphologic changes in the sagittal dimension using the Fränkel appliance.Am J Orthod. 1981;80(6):573-603.
Kerr MP,Welch Jr CD, Moore RN,Tekieli ME, Ruscello DM. Functional regulator therapy for cleft palate patients. Am J
Orthod. 1981;80(5):508-24.
80. McNamara Jr JA, Howe RP, DischingerTG. A comparison of the Herbst and Fränkel appliances in the treatment of Class II
malocclusion.Am J Orthod Dentofac Orthop. 1990;98(2):134-44.
81. • Records of patients who had been treated with the functional regulator (FR-2) of Frankel were
compared with records of patients treated with the acrylic splint Herbst appliance and also with
records of uritreated children with Class II malocclusion.
• Cephalometric study of treatment effects was carried out in 45 patients who had been treated with
the acrylic-splint Herbst appliance,.41 treated with the Frankel (FR-2) appliance, and 21 untreated
persons-- all individuals who had Class II malocclusion at the beginning of treatment. All subjects
were between 10-13 years at the time of the first cephalometric observation.
• Conclusion: Both the Herbst appliance and the Frankel appliance have measurable treatment effects
in dental and skeletal elements of the face. Both produced increases in mandibular length and
varying increases in lower anterior facial height. Greater dentoalveolar effects were observed
with the Herbst appliance than with the Frankel appliance.
82. • Baik(2004) FR III appliance, were selected and compared with a matched untreated Class III
sample. Cephalograms were taken before and after active treatment. The treatment effects
found were mainly from backward and downward rotation of the mandible and linguoversion
of the mandibular incisors.
• Janson(2007)
Baik HS, Jee SH, Lee KJ, OhTK.Treatment effects of Fränkel functional regulator III in children with Class III malocclusions. Am J Orthod
Dentofac Orthop. 2004 Mar 1;125(3):294-301.
Janson G, Nakamura A, de Freitas MR, Henriques JF, Pinzan A. Apical root resorption comparison between Fränkel and eruption guidance
appliances. Am J Orthod Dentofac Orthop.2007 ;131(6):729-35.
FR and eruption guidance appliances show root resorption but it was more
with EGA.
The prevalence of resorption for each incisor group, in decreasing order,
was maxillary central, maxillary lateral, mandibular central, and
mandibular lateral.
83. • Angelieri (2014) The correction of class II malocclusion by the FR-2 appliance occurred mainly by the
improvement of the maxillomandibular relationship due to the increase in mandibular length, with the
stability of these changes observed over 7 years post-treatment.
• The dentoalveolar changes demonstrated lesser stability over time, with the exception of the greater
mesial movement of the mandibular molars in the FR-2 patients than controls.
Angelieri F, Franchi L, Cevidanes LH, Scanavini MA, McNamara Jr JA. Long-term treatment effects of the FR-2 appliance: a prospective
evalution 7 years post-treatment. European journal of orthodontics. 2014 Apr 1;36(2):192-9.
85. • Occlusal inclined plane is the fundamental functional mechanism of the natural
dentition. Cuspal inclined plane play an important role in determining the
relation of the teeth as they erupt into occlusion.
• In case of class I relation the distal slope of the lower posterior teeth slide with
the mesial slope of the upper posterior teeth creating a mesial component of
force which is favourable for the normal mandibular development.
• In case of distoocclusion, the mesial slope of the lower posterior teeth slide
with the distal slope of the upper posterior teeth creating a distal component of
force that is unfavourable to normal forward mandibular development.
Clark WJ.The twin block techniqueA functional orthopedic appliance system.Am J Orthod. 1988;93(1):1-8.
86. MODE OF ACTION OF TWIN BLOCK
• Twin block modify the occlusal inclined plane and use the forces of
occlusion to correct the malocclusion.
• The unfavourable cuspal contacts of the distal occlusion are replaced by
favourable proprioceptive contact on the inclined plane of Twin block to
correct the malocclusion and to free the mandible from its locked distal
functional position.
• Due to the inclined plane effect a mesial component of force is created that is
favourable for the normal mandibular development.
87. • Upper and lower bite-blocks interlock at a 45°angle and are designed for full-time wear to take
advantage of all functional forces applied to the dentition including the forces of mastication.
• A much steeper incline, at least of 70° is more efficient. Since most of the day is spent with the mandible
at its rest position, tooth contact generally occurs only during swallowing, speech, and mastication. With
the blocks at 70° the mandible is maintained in a forward posture when at the rest position.
• This is because the hinge axis of opening is approximately 70° to the occlusal plane as demonstrated by
Posselt on mandibular movement.
• This allows 24-hour forward posturing when the masticatory system is at rest as well as in function.
Clark WJ.The twin block techniqueA functional orthopedic appliance system.Am J Orthod. 1988;93(1):1-8.
Trenouth MJ. A functional appliance system for the correction of Class II relationships. BJO. 1989;16(3):169-76.
88. Projet Bite Gauge: The Projet Bite GaugeTM is designed to record a
protrusive bite for construction of Twin Blocks .
• The blue bite gauge registers 2 mm vertical clearance between the
incisal edges of the upper and lower incisors, which is suitable for bite
registration in most class II division 1 malocclusions with increased
overbite.
• (a) select the appropriate groove for the upper incisors depending on
the size of the overjet and the ease with which the patient can posture
forward; (b) the lower incisors bite into a single groove to register a
protrusive bite; (c) bite registration for an overjet of up to 10 mm. The
blue Projet bite gauge gives 2 mm interincisal opening and there is 5–6
mm vertical space between the premolars.
Clark W. Design and management ofTwin Blocks: reflections after 30 years of clinical use. Journal of orthodontics. 2010
Sep;37(3):209-16.
89. • In the treatment of class II division I malocclusion with an anterior open bite an alternative Projet
Bite Gauge (usually white in colour) is selected that registers a 4 mm interincisal clearance.
• This results in approximately 5 mm clearance between the cusps of the first premolars or deciduous
molars.
• The objective is to open the bite beyond the freeway space, so as to intrude the posterior teeth, without
making the blocks too thick.
90. ACTION OF TWIN BLOCK
IN CL-II DIV. 1 DEEP BITE: The bite is opened by sequential
trimming of upper bite block occluso distally that allows the
lower posterior teeth to erupt.
IN OPEN BITE: The posterior bite blocks
remain unreduced and intact through out
treatment. This results in intrusive effect on
the posterior teeth, where as the anterior teeth
remain free to erupt.
Clark W. Design and management ofTwin Blocks: reflections after 30 years of clinical use. Journal of orthodontics. 2010
Sep;37(3):209-16.
91. • CL-II DIVISION 2: In addition to the sequential trimming of upper bite block the twin block is modified
by the addition of two sagittal screw set. The activation of the screw expand the arch by advancing the
upper incisor and at the same time, drive the upper buccal segment distally and buccally along the line of
the arch.
• Addition of one anterior screw with torquing spurs to both upper central incisors.
• A double cantilever spring behind the upper labial segment, followed by bonding of the upper labial
segment with pre-adjusted Edgewise fixed appliances.
Dyer FM, McKeown HF, Sandler PJ. The modified twin block appliance in the treatment of Class II division 2 malocclusions.
Journal of Orthodontics. 2001 Dec;28(4):271-80.
92. • IN CL-III MALOCCLUSION: Treatment of class-III malocclusion is achieved by reversing the
occlusal inclined plane to apply a forward component of force to the upper arch and a downward and
distal force to the mandible in the lower molar region.
93. • STAGE 1 -ACTIVE PHASE :The initial activation is checked when twin blocks are fitted to confirm that
the patient can comfortably maintain the altered postural position.
• Twin blocks are removed for eating for the first 3 days until the initial discomfort from appliance wear has
been resolved.
• The upper midline screw is turned a one-quarter turn every week to 10 days until the arch width is adequate
to accommodate the arch in its corrected position.
• Clinical response in active phase: Within a few days of fitting the appliances, the position of muscle
balance is altered so that it becomes painful for the patient to retract the mandible. This has been
described as the “pterygoid response” (McNamara) or the formation of a “tension zone” distal to the
condyle (Harvold).
• It is rare for such a response to be observed with functional appliances that are not worn full-time.
94. • Full correction of sagittal arch relationships can be achieved in as little as 2 to 6 months, giving a normal
incisor relationship with the buccal segments out of occlusion due to the presence of the bite-blocks. It is a
consistent feature in functional techniques that sagittal correction of arch relationships is achieved before
compensatory vertical development in the buccal segments is complete.
• STAGE 2-SUPPORT PHASE :The aim of the second stage of treatment is to retain the corrected incisor
relationship until the buccal segment occlusion is fully established, using an upper Hawley-type removable
appliance with an inclined guide plane to retain the sagittal relationship.
• The upper and lower buccal teeth are usually in occlusion within 4 to 6 months and the support phase is
continued for a further 3 to 6 months to allow functional reorientation of the trabecular system before the
position is retained.
95. • Lund (1998) Skeletal changes as a result of Twin Block therapy:
1. A mean forward growth/repositioning of the mandible of 2.4 mm, measured at Ar-Pog, was demonstrated
after Twin Block therapy.
2. The most noticeable skeletal change was an increase in the angle SNB, No significant maxillary restraint
could be demonstrated, There was an increase in lower anterior facial height.
Dental changes as a result of Twin Block therapy:
• The mean overjet reduction of 7.5 mm involved a net 10.8° retroclination of the upper incisors and 7.9°
proclination of the lower incisors.
• Buccal segment correction occurred by distal movement of the upper molars and lower molar eruption in an
anterior and superior direction.
Lund DI, Sandler PJ. The effects of Twin Blocks: a prospective controlled study. Am J Orthod Dentofacial Orthop.
1998;113(1):104-10.
96. • Elfeky (2015) evaluated the three-dimensional effects of a twin block (TB) appliance on the pharyngeal
airway parameters in a sample of Class II patients with mandibular retrusion in comparison with a control
group, by using cone-beam computed tomography (CBCT).
y Elfeky H, Fayed MM.Three-dimensional effects of twin block therapy on pharyngeal airway parameters in Class II
malocclusion patients. Journal of the World Federation of Orthodontists. 2015 Sep 1;4(3):114-9.
Conclusion: There was a significant increase in
nasopharyngeal, and oropharyngeal airway volumes
in the twinblock group.
97. • Kamal(2019) The odontoid process tangent (OPT) was drawn through the most posteroinferior point
on the second cervical vertebra (C2). The anterior and inferior angles created with sella-nasion (SN),
palatal plane (PP), and mandibular plane (SN-GoGn) were measured to determine any change in the
upper cervical posture. The cervical vertebral tangent (CVT) was drawn through the most
posteroinferior point on the fourth cervical vertebra (C4).
Kamal AT, Fida M. Evaluation of cervical spine posture after functional therapy with twin-block appliances:A retrospective
cohort study.Am J Orthod Dentofac Orthop. 2019;155(5):656-61.
Concluded that TB improves the sagittal relationships between the maxilla
and mandible, TB causes the craniocervical posture to be more upright.
Subjects with Class II malocclusion due to mandibular retrognathism with a
reduced vertical dimension have a greater forward inclination of the
craniocervical posture.
98. LIP BUMPER: Lip bumper is mainly indicated in case of lower lip
habit that flattens and crowds the lower anteriors.
MODE OF ACTION:
The lip bumper keeps the lower lip away from the lower anterior teeth
and there by eliminating the action of hyperactive mentalis and the
tongue will then stimulate the lower anteriors to move labially, which
increases the arch length and eliminate crowding.
99. CATALAN’S APPLIANCE
This appliance is used for the correction of single tooth in cross bite or a segment of upper arch in cross
bite.
MODE OF ACTION: The inclined plane transmits muscle forces directly to the teeth that are in cross bite
and cause labial tipping of the teeth.
100. HERBST APPLIANCE
• HERBST appliance designed by EMIL HERBST in 1905 and reintroduced by PANCHERZ
in 1979 who in the beginning primarily used it as a scientific tool in clinical research. Since
1979 the Herbst appliance has gained increasing interest and has grown to be one of the most
popular functional appliances for the therapy of Class II malocclusions.
101. • The appliance can be compared with an artificial joint working between the maxilla and
mandible.
• A bilateral telescope mechanism keeps the mandible in an anterior forced position during all
mandibular functions such as speech, chewing, biting and swallowing.
• In the earlier designs, the telescoping parts were curved conforming to the Curve of Spee. The
later designs were, however straight as they are today.
Each telescope device consists of a tube, a plunger, two pivots,
and two screws.
The tube was positioned in the maxillary first molar region and
the plunger in the mandibular first premolar or canine region.
102. • The screws prevent the telescoping parts from slipping off the pivots.
• The length of the tube determines the amount of bite jumping. Usually the mandible is retained in
an incisal end-to-end relationship.
• The length of the plunger is kept at a maximum in order to prevent it from slipping out of the tube when
the mouth is opened wide.
• If the plunger is too long, however, it may protrude far behind the tube and injure the buccal mucosa
distal to the maxillary permanent first molar.
• The mechanism permits vertical opening movements and, when properly constructed, also lateral
movements of the mandible.
103.
104. Modification in appliance design
• In Class II cases with a narrow maxillary dental arch, expansion can be performed in connection
with Herbst treatment by soldering a Quad-helix lingual arch wire or a rapid-palatal-expansion
device to the premolar and molar bands.
• If the first mandibular premolars have not yet erupted, the permanent canines can be used ;as
anchorage teeth. It must be pointed out, however, that the buccal mucosa at the comer of the
mouth is prone to ulceration when the mandibular canine is used as an abutment tooth for the
plunger.
• In the deciduous or early mixed dentition the bonded type of Herbst appliance”, may be used.
105. Considerations in appliance fabrication:
• The upper pivots should be placed distally on the molar bands and the lower pivots mesially on the
premolar bands .
• A large interpivot distance on each jaw side will prevent the plunger from slipping out of the tube when
the mouth is opened wide. If the plunger should disengage from the tube on mouth opening, it may get
stuck in the tube opening on subsequent mouth closure and damage the appliance (especially the bands).
The pivot openings on the tube and plunger should be widened
.This will provide an increased lateral movement capacity of
the mandible. Furthermore, the load on the anchorage teeth
(and bands) during mandibular lateral excursions will be
reduced.
106. • TREATMENT EFFECTS ON THE DENTOFACIAL COMPLEX :Twenty-two consecutive Class II,
Division 1 malocclusion cases treated with the Herbst appliance for an average time period of 6 months.
• Occlusal changes: Before treatment all patients had a bilateral Class II molar relationship, a large overjet
(mean, 8.2 mm), and a large overbite (mean, 5.5 mm). Six months of treatment with the Herbst
appliance resulted in (Class I (or overcorrected Class I) molar relationships, normal overjet (mean, 3.0
mm) and normal overbite (mean, 2.5 mm) in all twenty-two subjects.
• Sagittal cephalometric changes: The mandibular incisors proclined an ,average of 6.6 degree during 6
months of Herbst treatment. The position f the maxillary incisors was unaffected by treatment. The
Herbst appliance had a restraining effect on maxillary growth and a stimulating effect on mandibular
growth. Apparent mandibular length increased about three times more in the Herbst group than in the
control group.
Pancherz H.The Herbst appliance—its biologic effects and clinical use. Am J Orthod. 1985;87(1):1-20.
107. • Vertical cephalometric changes: In the twenty-two patients vertical overbite was reduced an average
of 3 .O mm (55%) during 6 months of treatment with the Herbst appliance.
• The mandibular incisors and maxillary molars were intruded during treatment, while eruption of the
maxillary and mandibular second premolars and mandibular molars was enhanced.
• Masticatory system: Class II malocclusion cases exhibit a diverging EMG pattern from the temporal and
masseter muscles when compared to normal occlusion cases. Treatment with the Herbst appliance normalizes
the EMG pattern from the two muscles.
• The Herbst appliance causes minor functional disturbances in the masticatory system. These disturbances are of a
temporary nature, appearing mainly at the beginning of the treatment period. –
• The patients experience chewing difficulties during the first 7 to 10 days of treatment, although chewing
ability is reduced during a much longer period.
Pancherz H.The Herbst appliance—its biologic effects and clinical use. Am J Orthod. 1985;87(1):1-20.
108. Pancherz H.The mechanism of Class II correction in Herbst appliance treatment: a cephalometric investigation. Am J Orthod .
1982;82(2):104-13.
109.
110. • As a rule, Class II cases cannot be treated to a perfect end result with the Herbst appliance
exclusively. Many cases will require a subsequent dental alignment treatment phase with a
multibracket appliance. Thus, treatment of a Class II, Division 1 malocclusion will usually occur in
two steps: STEP 1. ORTHOPEDIC PHASE. STEP 2. ORTHODONTIC PHASE.
• A Class II, Division 2 malocclusion may require a three-step treatment approach :
• STEP 1. ORTHODONTIC PHASE. Alignment of the anterior maxillary teeth by means of a
multibracket orthodontic appliance.
• STEP 2. ORTHOPEDIC PHASE.
• STEP 3. ORTHODONTIC PHASE.
111. • Ideal patient for treatment with the Herbst appliance has the following characteristics:
• Skeletal morphology: Retrognathic mandible, Small mandibular plane angle indicating an anterior
growth direction of the mandible, Normal or reduced lower facial height.
• Dental morphology: Class II dental arch relationships with increased overjet and normal or increased
overbite. The maxillary and mandibular teeth well aligned and the two dental arches fitting each other
in normal sagittal position. Minor crowding in the maxillary anterior segment.
• Maturation -Treatment during pubertal growth.
• As treatment with the Herbst appliance is performed during a relatively short period, the hard and soft
tissues (teeth, bone, and musculature) will need some time for adaptation to the new mandibular position
after the appliance is removed. Routine posttreatment retention with a removable functional appliance is
therefore recommended.
112. • Wieslander (1993) a group of children age 8 years 8 months were initially treated for 5 months with a
headgear-Herbst appliance followed by a 3- to 5-year period of activator retention. The patients were
studied out of retention at the mean age of 17 years 4 months and compared with an untreated control
group.
• CONCLUSIONS: Negative findings are as follows: 1. A prolonged retention ranging over several years
of activator wear was necessary to minimize relapse after Herbst treatment. 2.An average nonsignificant
1.5 mm net mandibular advance was all that was left out of retention of the 3.9 mm gained during
treatment.
• The significant average 2.0 mm increase in the condylion-gnathion distance observed after 5 months of
Herbst treatment was reduced to 1.2 mm after retention and was not statistically significant.
Wieslander L. Long-term effect of treatment with the headgear-Herbst appliance in the early mixed dentition. Stability or
relapse?. Am J Orthod Dentofac Orthop. 1993;104(4):319-29.
113. • Positive findings are as follows: 1. A rapid improvement of the anteroposterior jaw discrepancy
because of 24-hour wear of the appliance for 5 months. 2. A significant maxillary effect during active
treatment and retention resulting in a 2.3 mm posterior gain after retention, which compensates for the
mandibular relapse tendency. It resulted in an average statistically and clinically significant 2.9 ~
reduction of the ANB angle and a 3.8 mm skeletal improvement of the sagittal jaw relationship out of
retention.
• Findings indicate that maxillary sutural remodeling might be more receptive long-term to orthopedic
treatment than the mandibular condylar growth process.
Wieslander L. Long-term effect of treatment with the headgear-Herbst appliance in the early mixed dentition. Stability or
relapse?. Am J Orthod Dentofac Orthop. 1993;104(4):319-29.
114. • Ruf (2004) -46 adult Class II Division 1 subjects treated with a combined orthodontic-orthognathic
surgery approach (mandibular sagittal split osteotomy without genioplasty) and 23 adult Class II Division
1 subjects treated with the Herbst appliance.
• The mean pretreatment ages were 26 years for the surgery subjects and 21.9 years - Herbst patients.
• Conclusion: In the surgery group, the improvement in sagittal occlusion was achieved by skeletal more
than dental changes. Skeletal and soft tissue facial profile convexity was reduced significantly in both
groups, but the amount of profile convexity reduction was larger in the surgery group.
• Thus, Herbst treatment can be considered an alternative to orthognathic surgery in borderline adult skeletal
Class II malocclusions, especially when a great facial improvement is not the main treatment goal.
Ruf S, Pancherz H. Orthognathic surgery and dentofacial orthopedics in adult Class II Division 1 treatment: mandibular
sagittal split osteotomy versus Herbst appliance.Am J Orthod Dentofac Orthop. 2004;126(2):140-52.
115. • Iwasaki (2014) Herbst appliance enlarges the oropharyngeal and laryngopharyngeal airways. These
results may provide a useful assessment of obstructive sleep apnea treatment during growth.
• Siara-olds (2010) 1) Temporary restriction of maxillary growth was found in the MARA group (T2–
T1). (2) SNB increased more with the Twin Block and Herbst groups when compared with the
Bionator and MARA groups. (3) The Twin Block group expressed better control of the vertical
dimension. (4) The overbite, overjet, and Wits appraisal decreased significantly with all of the
appliances.
• No significant dentoskeletal differences were observed long-term, among the various treatment groups
and matched controls.
IwasakiT,TakemotoY, Inada E, Sato H, Saitoh I, Kakuno E, Kanomi R,YamasakiY.Three-dimensional cone-beam
computed tomography analysis of enlargement of the pharyngeal airway by the Herbst appliance.Am J Orthod Dentofac
Orthop. 2014;146(6):776-85.
Siara-Olds NJ, Pangrazio-KulbershV, Berger J, Bayirli B. Long-term dentoskeletal changes with the Bionator, Herbst,Twin
Block, and MARA functional appliances.The Angle Orthodontist. 2010 Jan;80(1):18-29.
116. Conclusion
• The past 20 years have seen an increasing awareness of the potential of functional
appliances as valuable tools in the armamentaria of orthodontists.
• An increasing recognition of the interrelationship of form and function, the realization that
neuromuscular involvement is vital in treatment, the recognition of the importance of the
airway in therapeutic considerations and a growing understanding of head posture and the
accomplishments of dentofacial pattern changes are all factors producing rapid growth in
use of functional appliances.
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122.
123. • he Bimler Appliance Just as Andresen’s discovery of the activator was an accidental
outgrowth of his retainer, so was Hans Peter Bimler’s (1916-2003) (Fig 4)
elastischerGebissformer (elastic bite former) fortuitous development. As a surgeon treating
jaw injuries during WorldWar II, Bimler had devised a maxillary splint for a patient who had
lost his left gonial angle.The splint provided a guide into which the patient could insert the
remainder of his mandible. Hans Bimler got his inspiration for Gebissformer asWorld War II
army surgeon. 9/2/2013Functional appliances- I33
Hinweis der Redaktion
In contrast to intermaxillary elastics that are removed and replaced by the patient, SAIF springs provide a fixed pulling force. This mechanism has not been used widely because of difficulties encountered in appliance management, including breakage, hygiene, and comfort problems.
Originates from the great wing of the sphenoid bone.,inserts on the temporomandibular joint (TMJ),………………….. Originates from the outer surface of the lateral pterygoid plate.,inserts on the condyloid process of the mandible,………..
The stimulus for stretch reflex is the stretch of the muscle. Muscle spindles act as stretch receptors.
Impulses arising from the muscle spindle are conducted by the group IA sensory nerve fibers.
In the mandible, the stretch reflex acts to maintain the postural rest position of the mandible in relation to the maxilla.
The impulses are conducted by group 1B sensory nerve fibers, the impulses act on the motor neuron of alpha efferent supplying the stretched muscle. The receptors for the clasp knife reflex are the Golgi tendon organs located in the tendon of the muscle.
This prevents the muscles from being overactivated or overstretched, which could lead to muscle fatigue that is undesirable because it will result in contact of the lingual shield with the lingual surface of the anterior alveolus causing mandibular incisor flaring.
eruption guidance appliances ……………. are constructed of an elastomeric material with intercuspation for the maxillary and mandibular teeth in normal occlusion. These prefabricated appliances advance the mandible to correct Class II sagittal discrepancies
The anterior and inferior angles created with the aforementioned planes and the angle between OPT and CVT were used to determine any change in the middle cervical posture…………………The results showed a significant difference between the PF1 and PF2 SNB, ANB, and OPT/CVT angles, indicating an improvement in sagittal relationships and an increase in cervical curvature.
