Bionator /certified fixed orthodontic courses by Indian dental academy
INDIAN DENTAL ACADEMY
Leader in continuing dental education
Functional jaw orthopaedics is the system of orthodontic treatment
which makes use of the forces which act in and about the human
dentition during the activities of the masticatory face
Functional appliances are considered primarily as a orthopedic tool to
influence the facial skeleton of the growing child in the condylar and
sutural area.They harness natural forces which is transmitted to the
teeth and the alveolar bone in a predetermined direction.
Function is inherent in all cells, tissues, and organs and influence
these media as a functional stimulus.
The goal of functional dental orthopedics is to use this functional
stimulus channeling it to the greatest extent, the tissues, jaws,
condyles and teeth allow.
The uniqueness of functional appliances lie in their mode of force
Principles of functional jaw
According to Roux and Wolff form was intimately related to function.
Changes in functional stress would produce changes in internal bone
architecture and external shape. .
According to haupl et al tissue forming stimuli originate from the activity
of the tongue,lips ,facial and masticatory muscles .These stimuli are
transmitted to the teeth ,paradental tissue, alveolar bone and
mandibular joint through a passive ,loose fitting appliance inserted
between the teeth,the result being that the transmitted stimuli induce
desired changes in the tissues affected.
Force in orthopedic procedures
Forces employed in orthodontic and orthopedic procedures are
Mechanical appliances use compressive forces and pressure strain
Functional appliances use tensile forces causing stress and strain
1.External forces (primary)
2.Internal forces (secondary)
External forces are
i.Occlusal forces on the dentition
ii.Muscle forces from the tongue, lips and cheeks.
Reaction of tissues to primary forces
Internal forces strain the contiguous tissue leading to deformation and
bracing of the alveolar process
Two treatment principles in the use of forces in functional jaw
Here abnormal and restrictive forces and environmental
influences are eliminated ,allowing optimal development
lip bumper and frankel buccal shield
In this compressive stress and strain act on the structures
involved resulting in secondary adaptation to function.eg all
active removable appliances
Various parameters of force application are
Duration of force in most functional appliances is interrupted
because they are usually worn for 12 to 14 hours a day. The
bionator is worn continuously except during mealtimes and sports.
Direction –It should be consistent in a particular direction
Magnitude-Magnitude of force in functional appliance is usually very
small. If the induced strain is to great ,patient will have difficulty
Forces acting on the erupting teeth
Bucco-lingual forces from the
musculature of the lips cheeks
Mesiodistal forces adjacent
to the teeth.
Forces generated by the muscles
1.Passive forces–due to the
muscle tonus which is continous
but very light
2.Active forces- due to muscle
activity which is always
Mode of action of various functional
appliances –the causal chain
1.Increased contractile activity of the lateral pterygoid muscle
2.Intensification of the repetitive activity of the retrodiscal pad
3.Increased in growth stimulating factors
.Enhancement of local mediators
.Reduction of local regulators
4..Change in condylar trabecular orientation
.Additional growth of condylar cartilage
.Additional subperiosteal ossification
5.Supplementary lengthening of the mandible
Evolution of the bionator
The bionator was introduced by Balter in germany in 1950
The bionator is a modification of the activatior
It is the skeleton of the activator because it has more of metal
Bionator differs from the activator in
1.It is less bulky than the activator.
2.It lacks the part covering the anterior section of the palate.
Therefore children are able to speak normally
3..Bionator can be worn at day and night except mealtimes.
Principles of bionator therapy
Theories upon which the bionator is based
1.Based on the works of Robin, Andresen,and Haupl
2.The early function and form concepts of Van der Klaaw and the
functional matrix theory of Moss
The Functional matrix theory
According to van der klauw
Functional matrix means the non osseous structures of the craniofacial
skeleton.They function in the form of a matrix by stimulating and
holding things together.
The soft tissue unit is the functional matrix
The skeletal unit is the functional cranial component
Principles of bionator therapy….
The functional matrix theory
There are two types of functional matrix
1.Periosteal functional matrix
Which comprises of the muscles, blood vessels, nerves and glands.
2.The capsular matrix
Which consists of the cerebral matrix and the facial matrix (eg. Neural,
optical and orbital masses)
According to van der klauw the presence or absence of soft tissue
structures produce a response in the bone affecting it’s soft tissue
Principles of bionator therapy….
The functional matrix theory
Also the functional matrix theory states that two factors are responsible
The intrinsic factor (genomic factor
The extrinsic factor (epigenetic factor)
The epigenetic factor which are the extraskeletal factors and processes
are the primary cause of adaptive and secondary changes.
Principles of bionator therapy …
To quote balter ,
The equilibirium between the tongue and the circumoral muscles
especially between the tongue and the lips in the hieght , breath and
width in a oral space of maximum size and optimal limits providing
functional space for the tongue is essential for natural health of the
dental arches and their relation to each other .Every disturbance will
deform the dentition and during growth that may be impeded too.
The tongue is the essential factor for the development of the
dentition .It is the center of reflex cavity in the oral cavity.
Balters treatment objectives
1.To accomplish lip closure and bring the back of the tongue into
contact with the soft palate.
2.To enlarge the oral space and to train its function
3.To bring the incisors into edge to edge relationship
4.To achieve an elongation of the mandible which will enlarge the oral
space and make improved tongue position possible
5.To achieve an improved relationship of the jaw , tongue and dentition
as well as the surrounding tissues.
Role of tongue in bionator therapy
The tongue is the most important factor in treatment using the bionator
A discoordination of the function could lead to abnormal growth and
The purpose of the bionator is to establish good functional coordination
and eliminate these deforming and growth restricting aberrations
According to Balter a class II malocclusion is due to a backward
positioning of the tongue ,disturbing the cervical region. Respiratory
function in the region of the larynx is impeded and there is faulty
deglutition associated with mouthbreathing.
Tongue exerts 3 to 4 times as much pressure on the dentition as does
the buccal and labial muscultare.This supports ballter’s hypothesis
that the tongue is the chief cause of malocclusion. Abnormal tongue
development can be secondary ,adaptive or compensatory because
of skeletal maldevelopment.
Position of the tongue vs
Posterior displacement of the tongue-Cl II Malocclusion
Low anterior displacement of the tongue-Cl III Malocclusion
Hyperactivity and forward posturing of the tongue –open bite
Diminished outward pressure during both postural rest and function
as opposed to the forces of the buccinator mechanism on the
outside - Narrowing of the arches with resultant crowding
particularly in the maxillary arch
Mechanism of action of Bionator
The bionator modulates the activity of the muscle
1.Enhances normal development of inherent growth pattern
2.Eliminating abnormal and potentially deforming environmental
Indications for bionator therapy
In actively growing children for the management of class II division 1
or class II division2
In class I malocclusion with deep bite
In class III
Treatment of ClassII division I malocclusion in the mixed dentition is
indicated only under the following conditions.
1.The dental arches are well aligned originally.
2.The mandible is in functional retrusion.
3.The skeletal discrepancy is not to severe.
4.A labial tipping of the upper incisors is evident.
Contraindications to bionator
The bionator is not indicated in the following conditions
1. The class II relationship is caused by maxillary prognathism.
2.A vertical growth pattern is present.
3.Labial tipping of the lower incisors is evident. Anterior posturing of the
mandible with simultaneous up righting of the lower incisors cannot
be performed with the bionator.
4. Children with neuromuscular diseases such as poliomyelitis and
cerebral palsy cannot be successfully treated with functional
appliances because functional appliance therapy depends on
Assessment to be made before
The following assessment are to be made before planning treatment
Whether malocclusion is skeletal or dental
Whether malocclusion is functionally true or functional retrusion
Forecasting of growth direction
Assessment of growth potential and growth increments
Differentiation of hereditary malocclusion and neuromuscular
The following are the chepalometric criteria
-The relationship of the maxilla to the cranial base is considered
-The position and size of the mandible
-The axial inclination and position of the incisors
-The growth pattern
Functional criteria for treatment
planning for class II malocclusion
The functional criteria include
-The assessment of relationship between rest position and
occlusion to differentiate between functional retrusion and forced
-The examination of relationship between overjet and function of the
-The posture and function of the tongue should be assessed
-assessment of mode of breathing
Types of Bionator
There are three basic types
1.Standard bionator for class II division malocclusion
3.Reversed or Class III bionator
Uses of a standard bionator
1.In the treatment of class II division I malocclusion in order to correct
the backward position of the tongue and its consequences.
2.For the treatment of narrow dental arches of class I malocclusion
3.Construction bite or acrylic portion
The vestibular wire or labial bow
It is made of 0.9mm stainless steel
wire .It emerges from the acrylic below
the contact point between the upper
canine and the premolar .it rises
vertically and then bent at right angle
to go distally along the middle of the
crowns of the upper premolar just
below the mesial contact of the first
molar the wire is fashioned in a round
bend towards the lower dental arch
from here it runs anteriorly at about the
same position with respect to the
buccal surface of the lower posterior
teeth as far as the lower canine
From there it at a sharp angle it extends obliquely upwards towards the
upper canine , bends to a level line at approximately the incisal third of
the incisors and extends to the canine of the opposite side .it ends in a
mirror image form of the opposite side and inserts in acrylic.The labial
surface of the bow should be away from the incisors by approximately
the thickness of writing paper
Function of labial bow in standard bionator
1.To guide the posture and function of the lips
2.The posterior portion of the labial bow
are designed as buccinator loops
They keep the soft tissue away of the cheeks
which is normally drawn into the interocclusal
space.the construction bite may be trimmed
facilitation eruption of the buccal segment.
They actually move the surface of the
orobuccal capsule laterally ,.this remval of
inhibitory influence favours expansion or
transverse developmwent of the maxillary
Function of labial bow in standard bionator…………
3.The position of the wire provides a negative pressure supporting lip
closure.In course of treatment the wire uprights the incisors and
provides for extra space when the arch is to widened
4.The labial bow similar in function to the acrylic shields of frankel
The palatal bar
It made of 1.2mm stainless wire .It
emerges from the upper margin of
the acrylic, approximately opposite
to the middle of the first premolar .it
follows the contour of the palate at
about 1mm from the mucosa .It
forms a wide arch that reaches the
distal surfaces of the first molars
and it forms a mirror image curve to
insert on the opposite side.
Function of palatal bar
1.Stimulates the distal aspect of the tongue
2.Simulteanously orients the tongue and mandible anteriorly to achieve
class I relationship
3.It stabilises the appliance
4.It is not intended for expansion of the arch
Standard bionator …..
It consists a of horse shoe shaped acrylic lingual plate extending distal
to the last erupted tooth on either side in the lower arch. For the
upper arch the appliance is open from the canine to the canine
region with aryclic in the posterior section that cover the molar and
premolars..The bite should not be opened and must be positioned in
an edge to edge position. If some space is present between the
upper and lower incisors the acrylic is extended to cap the lower
If the ovejet is to large the forward positioning is done step by step but
should not open the bite. Edge to edge relationship of all the teeth
or at least the lateral incisors provides maximal functional space for
the tongue. A construction bite must always be taken on the patient
and not on the cast.
Function of construction bite
1.It prevents the cheek and tongue from interposing in the interocclusal
2.Proper trimming will facilitate eruption of teeth.
Open bite appliance
Uses of open bite appliances
1.To close the aperture in the
anterior or in the lateral
2.Used in TMJ dysfunction cases
3.Construction bite or acrylic
Open bite appliance....
Function of labial wire
1.It is placed at the height of
correct lip closure to stimulate
the lip to achieve a competent
seal and relationship
2.Vertical strain on the lips tend to
encourage the extrusive
movements of the incisors
which facilitates closure of the
open bite after eliminating the
adverse tongue pressures.
Open bite appliance….
The palatal bar is constructed similar to a standard appliance.
Function of palatal bar is to move the tongue into a more caudal and
the construction bite is kept as low as possible with a slight opening
which allows for interposition of the posterior acrylic bite blocks thereby
preventing eruption of the posterior teeth
Class III bionator or reversed bionator
It is used in the treatment of
classIII malocclusion by
encouraging development of the
The labial bow runs in front of the
lower incisors. It prevents labial
tipping of the lower incisors.
Class III bionator or reversed bionator….
The palatal bar
The palatal bar is reverse in position to that of the standard bionator.
This stimulates the tongue to remain in a retracted position in its
proper functional space. It contacts the anterior portion of the palate
encouraging the forward growth of the area.
The construction bite is taken in the most retruded position. The
construction bite is similar to that of the standard bionator except
that it is extended in the behind the lingual surface of the upper
incisors which are stimulated to glide along the upper inclined
plane.The acrylic behind the lower teeth is trimmed by 1 mm to
prevent labial tipping of the lower incisors.
Trimming the bionator
The trimming of the occlusal surface of the bionator is essential to allow
certain teeth to erupt further while preventing fully erupted teeth from
further eruption through contact with the acrylic.
Balter refers to
Stimulation of eruption as unloading or promotion of growth and
Prevention of eruption as loading or inhibition of growth
Terminology in trimming the
1.Articular plane-this plane
extends from the cusps of
The upper molars,premolars,
and canines to the mesial
margin of the upper incisors.
It is parallel to the alatragal
Line.it is important for the
assessment of growth
Terminology used in trimming the
2.Loading area-The palatal or
lingual cusps of the
deciduous molars and
permanent first molars
are relieved in acrylic .
this enhances the
anchorage of the appliance.
Terminology used in trimming the
Some parts of the loading area
are trimmed away to the articular
plane. This acrylic surface is
called the tooth bed
Terminology used in trimming the
A reduced plastic extension
placed on the occlusal third of
interdental area is called a
ledge.this lies between the
premolars or decidous molars.
This acts as a guiding surface for
the eruption of teeth
Terminology used in trimming the
Between the tooth beds,
Interdentally acrylic finger like
projections called noses can be
fabricated. These extensions act
As guiding panes and sources of
Trimming the bionator….
Unloading of the upper and lower molars cause extrusion.
Trimming the bionator….
Loading of the upper and lower molars cause a expansion effect on
the upper teeth
Trimming the bionator….
loading of the upper molars and unloading of the lower molars
cause eruption of the upper molars.
Stabilization of the bionator
The appliance is stabilized
-In the mixed dentition by having the upper and lower deciduous molars
occlude on the acrylic.
In the permanent dentition this is accomplished by having the
maxillary premolars occlude in the acrylic
-The occlusal part of the acrylic bite block will be ground flat to allow for
transverse expansion of the dental arch.
-No acrylic covers the first molars which permits for further eruption
and leveling of the bite.
Stabilization of the bionator….
The following teeth can be used for stabilization depending on the
presence or absence of teeth.
IV,V upper and lower
V and space after 1V
6 and the alveolar process
Anchorage of the appliance
Stabilisation or anchorage is provided by
Insical margin of the lower incisors,by extending the acrylic over the
incisal margin as a cap.
In the loading area the cusps of the teeth fit into the respective grooves
Decidous molars and edentulous spaces serve as areas of anchorage.
Noses in the upper and lower interdental spaces.
Labial bow when it is correctly placed prevent posterior displacement of
Bionator and the TMJ
Tmj problems are associated with bruxism and clenching during the
REM period of sleep
Mechanism of action-Bionator relaxes muscle spasm particularly that
of the lateral pterygoid muscle.
Design of the appliance-Similar to a standard appliance except the
construction bite need not move the mandible forward
Purpose of the appliance-To prevent riding of the condyle over the
posterior edge of the disc and thereby prevent clicking .
Function of the bionator-to maintain the mandible in a forward position
and prevent deleterious parafunctional effects at night.
Bionator and the TMJ……
Construction biteIt is opened slightly and the lower incisors are capped.
No grinding is done
When the acrylic is worn it loads both the upper and lower buccal
segment guiding the mandible forward during the clencing or bruxing
Bionator therapy with local application of heat and muscle relaxants
provide immediate relief
Bionator and the TMJ…..
Adult Class II patients learn a accomodative forward positioning of the
mandible as the muscles adapt to the new position
The adaptation is due to a foreshortening of the protracting muscles of
Duration of wear -the appliance should be worn indefinitely as a splint
Causes of failures due to bionator
1.Lack of patient co-operation
3.Poor growth direction
4.Inadequate growth increments
5.Poor treatment timing
Clinical management of bionator
The appliance should be loose and should fall when the mouth is open.
The time interval between office visits is 3 to 5 weeks depending upon
the state of eruption of the tooth.
The labial bow should be checked to ensure that it touches the teeth
The buccinator loops should be away from the decidous first molars but
should not irritate the cheeks.
In accordance with the plan of anchorage an growth promotion,loading
and unloading of acrylic areas can be done depending o the teeth to
Any modifications are done in the following order
The lower premolars secondly
The upper premolars in the end.
These areas are alternately loaded or unloaded for anchorage
prognosis bionator therapy
Bionator therapy is successful in actively growing children
-with class II division1,and class II division2.
-Class I malocclusion with deep-bite
-Pseudo class III
-Maloccusion caused due to lip sucking,lip and tongue interposition,or
Favourable outcome is limited
In the presence of skeletal discrepancies such as skeletal open bite
mandibular prognathism and transverse basal arch disharmony.
In patient in whom facial growth has been completed.
Marked crowding that requires extraction for alignment.
It should be worn both during the day and night except during meals
and during sports.
The appliance should be worn while giving short speeches
The appliance is removed b shing it oih the tongue
Advantages and Disadvantages of
The main advantages is the reduced size.So it can be used day and
night.it exerts a constant influence on the tongue and musclature
because of the longer duration of wear the correction of malocclusion is
faster because the mandible only during mealtimes
Disadvantages of the bionator
Correct management of the appliance is necessary.
Stabilization of the appliance and selective grinding of etive gidnce is
limited effectiveness in skeletal distbnces.
Vlneble to distortion since thee is less lic in he alveol and incisl region
No llonce fo veicl goth comonent excet tht it llos fo giding etion of osteio
Modification of bionator
Modification of bionator-the
biomodulator of fleischer
The following are modifications
in bionator design
The Acrylic body of the
bionator is reduced in size
extending along the alveolar
process than the original
A maxillary buccolingual arch
wire and a separate labial wire
is used instead of the labial
wire with buccinator loops
The transpalatal arch opens in
the distal direction
Sagittal anchorage is
reinforced with spurs locted
mesial to the maxillary canine
or the maxillary first molar.
Modification of the bionatorThe bio-M-S appliance
This appliance is similar to a
biomodulator but in addition to
the other co incorporates a metal
occlusal bite plane into the
bionator to facilitate correction of
The upper margin of the acrylic
along the palatal margin of the
incisors tapers to a thin edge to
facilitate pronunciation of s sound
.The anterior part of the bionator
is slightly concave to leave
maximal space for the tongue.
It is made of 1.2mm wire.
Opens in the distal direction
Parallel to the occlusal plane near
the palatal aspect of the molars.
Maxillary labial bow
Made of 0.9mm wire
Contoured along the labial
surface of the incisors at the level
of the interdental papilla
Between the canine and the
premolar a loop is formed
approximately 10mm in diameter.
The retentive part is bent
The labial arch wire is kept about
1mm to 3mm away from tha labial
surface of the teeth.
Mandibular labial bow
It is made of 0.9mm wire
-In the area of the premolars it
has a u shaped loop 8mm in
-The wire enters the acrylic distal
to the canine close to the
-To avoid irritation to the lip a
wave like pattern is given to
the labial bow or the wire can
be covered wire soft elastic
In class III malocclusion the labial
wire is placed near the incisal
edge of the incisors to to avoid
interference with the occlusally
directed forces transmittedwww.indiandentalacademy.com
Stops at the mesial surface of the
maxillary molars serve as
auxiliaries for sagittal
anchorage.the wire is turned
gingivally into a small loop
approximately 3mm in
diameter.and placed on the
mesiobuccal aspect of the first
Used when the canines have not
It’s placed on the mesial surface
of the maxillary canine.
Metal bite plane
Made of 0.5mm stainless steel
sheet metal adapted to the shape
of the individual dental arches
Purpose of a metal guide plane
-as a guide for vertical
-Promotes vertical equilibration of
the occlusal surface of premolars
and molars by allowing teeth that
do not touch the bite plane to
erupt further while restricting the
eruption of teeth that touch the
- correction of deep bite.
It’s a small metal plate
fitted onto the labial
surface of the metal
occlusal bite plane to provide for
In the anterior region has a
retruding effect on the incisors.
In the buccal surface of molars
and premolars can be used in
the correction of cross bite.
The construction bite
It serves as a guide for vertical
development and correction of
In a class II division 2, a flat plane
permits differential control of
Lower premolars in
excessive curve of spee.
Advantages of a metal occlusal plane
It eliminates the tedious procedure of
trimming the acrylic as in
conventional functional appliances.
Effectiveness of early treatment with
haedgear/biteplane vs the
When factors such as sex, race, intial molar severity and compliance is
taken into account headgear treatment is superior to bionator treatment
although relapse after phase I therapy is greater with headgear than
with bionator. phase I therapy is considered to be successful if molar
correct from a full cusp classII to to a one fourth cusp class II
Frankel vs the bionatorAJO 2002
A significant increase in mandibular growth and degree of
protrusion with the increase greater in the bionator
Anterioposterior relationship between the maxilla and the mandible
increased significantly in both the bionator and frankel
Both appliances produce similar labial tipping and linear protrusion
the lower incisors,lingual inclination and retrusion of the upper incisors.
A significant increase in mandibular posterior dentoalveolar hieght
and not extrusion of the upper molars in both group
No significant on craniofacial growth and restriction of maxillary
Chepalometric markers to be considered in
the treatment of classII division I
malocclusion with bionator AJO 2001
Important indicators of good result are
1.Horizontal growth pattern
It should be close to the normal anterio- posterior relationship between
the maxilla and mandible.
2.Upright mandibular incisors
3.Retrusive lower lip-protrusion of the lower lip was the most important
factor in the determination of treatment results.
Anterioposterior skeletal and dental changes
after early class II treatment with bionator
and headgear AJO1998
The headgear/biteplane and bionator do not affect maxiilary growth
during treatment in 9-10 years.
Both appliances enhance mandibular anterior growth.
Mandibular response to orthodontic
treatment with the bionator applianceAJO 1990
The subjects with delayed growth may experience more mandibular
development than those with average growth during treatment under
the favourable growth environment created by the functional appliance.
Patient with small mandible may experience more benefit than patients
with normal mandible.
Changes in condylar position indicated a more distal post-treatment
condylar position in patient with a greater mandibular advancement
Compared to patient who had a small mandibular advancement.
Thus the anterior positioning of the condyle that takes place with
appliance therapy may be diminished with greater mandibular
The bionator is the most commonly used modification of the
activator.It is the appliance of choice for begginner in functional
appliance therapy as it has very little wire components.With proper
case selection ,diagnosis and treatment planning the bionator can
be used as an effective functional appliance during the period of
Leader in continuing dental education