Treatment of class 2

1. Dr.Kailash Rathi
Dept of Orthodontics and Dentofacial
Orthopedics
S.B. Patil intitute for Dental Sciences
and Research

2. CLASS II MALOCCLUSION-
• The mesiobuccal cusp of maxillary 1st permanent
molar occludes in the interdental space mesial to the
mesiobuccal cusp of the Mandibular ist permanent
molar and distal to the buccal cusp of the mandibular
2nd premolar
• INCIDENCE-20-25%
• TYPES-CLASS 2 DIVISION 1
CLASS 2 DIVISION 2

3. CLASS II DIV I MALOCCLUSION
ETIOLOGY-
PRENATAL-hereditary
-teratogenesis
-irradiation
-intra-uterine fetal posture
NATAL-improper forceps application during delivery
can result in trauma to the condylar region leading to
underdevelopment of the mandible
POSTNATAL-trauma
-long term irradiation therapy of the
cranio-facial region
-infectious conditions eg.rheumatoid arthritis
-habits eg.thumb sucking
-local factors leading to undergrowth of mandible
eg.malnutrition,vitamin deficiencies,
hormonal disturbances

4. FEATURES-
-class 2 molar relation
-proclined maxillary anteriors
-increased overjet
-excessive curve of spee
-short hypotonic upper lip with lip trap
-abnormal buccinator activity
-constricted upper arch
-convex profile
-(sometimes….proclined lower anteriors in the
form of a compensation to reduce the overjet)
TYPES-Skeletal
Dentoalveolar
Functional

5. BEFORE STARTING THE TREATMENT-
Assessment of Growth Pattern and Growth Trends is
very important
TREATMENT OBJECTIVES-
-reduction of overjet
-reduction of overbite
-correction of crowding & local irregularities
-correction of molar relationship
-correction of posterior crossbites if any
-normalizing the musculature

6. TREATMENT IN DECIDUOUS DENTITION -
-Elimination of deleterious habits like thumb sucking
-Use of lip bumper,oral screen and lip and tongue
excersises
-Use of distal shoe space maintainer in case of premature
loss of deciduous molar
Lip bumper Oral screen

7. -Anterior bite plane for deep bites
-Growth modification procedures are not started due to-
-chances of relapse
-long period of retention required till growth is
complete (patient incompliance)
-successful results using pubertal growth spurts can
be obtained

8. TREATMENT OF MIXED DENTITION
-Diagnosis of the problem-whether skeletal,dental or functional
and functional analysis-Cephalometric analysis are ESSENTIAL
GROWTH MODIFICATION has 2 principles
(1)should start before adolescent growth spurt
period preferably 1-2yrs before as a safety measure
(2)it should be continued atleast at reduced levels until
growth is essentially complete to prevent relapse
-.PRE-ORTHOPEDIC PHASE-
If maxillary arch is excessively narrow-slow expansion or R.P.E.required

9. -WITH USE OF FUNCTIONAL APPLIANCES -
•MECHANICS-
(1)Acceleration of mandibular growth
(2)Restraint of maxillary growth(`Headgear effect`)
(3)Backward tipping of maxillary incisors & forward tipping of the
mandibular incisors & the entire mandibular dentition
(Class II elastics effect)
(4)Differential eruption of teeth
A)CORRECTION OF MANDIBULAR DEFECIENCY-
Class II elastics effect

10. An ideal patient for a functional appliance-
(1)Skeletal mandibular retrusion
(2)Normally positioned or retrusive but not protrusive lower incisors
(3)Normal or slightly excessive maxillary development
(4)Upright or slightly protusive maxillary anterior teeth
(5)Normal or slightly short face height
FUNCTIONAL APPLIANCES are either teeth borne or tissue borne-
•Removable like Activator, Bionator, FRII, Twin Block,etc.
Activator
FR II Bionator

11. Pre treatment
photographs
Post treatment
Activator

12. •Fixed Functional Appliances like Herbst Appliances,Jasper Jumper
Conn`s Mandibular Advancer etc.
•Functional Appliances with Magnets like Magnetic advancement
Device ( MAD2),Functional Orthopedic Magnaetic Activator(FOMA2)
Herbst Applince Jasper Jumper

13. before
after
Herbst appliance

14. before
Jasper jumper
before
after

15. B)TREATMENT OF MAXILLARY SKELETAL
PROTRUSION
-WITH USE OF EXTRA ORAL TRACTION-
An ideal patient for treatment with Extra-Oral traction-
(1)Skeletal maxillary protrusion
(2)Some protrusion of maxillary teeth
(3)Reasonably good mandibular dental & skeletal morphology
(4)Potential for continued spontaneous mandibular growth
Cephalometric superimposition
showing growth modification
produced by extra oral force to
the maxilla

16. Camouflage by extraction of premolars
before
after

17. • Cervical Head gear -in patients with decreased vertical dimension
•Combination Head Gear (Head Cap with a Cervial neck strap)

18. To produce maximum skeletal changes with minimum tooth movement -
FORCE PRESCRIPTION used-
(1) Heavy Force-500-1000gm (half that per side)
(2) Force Duration-12-14hrs/day
(3) Force direction slightly above the occlusal plane (through centre of
resistance of molar teeth)
(4) Duration of treatment -12 to 18 months depending on growth and
patient cooperation

19. MAXILLARY DENTOALVEOLAR PROBLEMS-
(1) Anteroposterior position of the 4 incisors-
Can be TREATED using-Removable appliances like springs,screws etc.
Fixed appliances like the utility arches
(2)Protrusion of the entire maxillary dental arch
EITHER Retract the upper anteriors following removal of 2premolars
Move the maxillary dentition `en masse` using distalisation
mechanics
..DISTALISATION OF MAXILLARY MOLARS
-Removable Appliances like Finger springs
Expansion Screws
Split Saddle acrylic space regainer
Slingshot regainer

20. -Fixed Appliances like Headgear
Open coilsprings-stainless steel or NiTi
Pendulum appliance
Sliding jigs like Lokar`s appliance
Wilson`s Distalising Bimetric Arch
Pre & post distalisation using coil springs(unilateral)

21. MANDIBULAR DENTOALVEOLAR PROBLEMS
as per patients need.. Use of -Lip Bumper
-Oral Screen
-expansion plates and fixed appliances
-Functional appliance + Headgear
eg.TEUSCHER`S APPLIANCE
(Activator +Head gear)

22. pre post
pre post
Distalisation
using coil
springs
(bilateral)
Distalisation
using
pendulum
appliance

23. TREATMENT IN PERMANENT DENTITION-
CAMOUFLAGE- extraction of teeth and moving the rest
of the teeth in the space created
(1)Extraction of upper 1st premolars which will permit-
reducing premaxillry protusion
elimination of excessive overjet
establishment of normal perioral musculature
(2)Extraction of both Maxillary and Mandibular 1st Premolars in
cases of significant arch length discrepancie in both the arches

24. ORTHOGNATHIC SURGERY in severe skeletal malrelation
-on maxilla-Retraction by removal of a premolars, segmentation and
movement of the anterior segment into the space created
-Le Fort I Osteotomy
-on mandible-Bilateral Sagittal Split Osteotomy(BSSC)
Line of treatment-
-LE FORT I OSTEOTOMY
-BILATERAL SAITTAL SPLIT OSTEOTOMY
-Before the
treatment

25. before
after
after

26. CLASS II DIV II MALOCCLUSION
FEATURES-
(1)Molars in disto-occlusion
(2)Retroclined central incisors and rarely other incisors
(3)Deep overbite
(4)Broad square face
(5)Backward path of closure
(6)Deep mentolabial sulcus

27. TREATMENT OBJECTIVES-
-Relief of gingival trauma
-Correction of incisor relationship
-Relief of crowding and local irregularities
-Correction of buccal segment relationship
TREATMENT IN DECIDUOUS AND MIXED
DENTITION -
-Principles remain the same -convert Class II DivII into Class II DivI
-PRE-ORTHOPEDIC treatment phase- for Retroclined maxillary
incisors using springs and screws
-for deep bite- Anterior bite platform,Functional Appliances

28. -Begg`s Appliance-Anchor bends, `V` bends, Bypass arch wires
-Edgewise Appliance-Utility Arches,Reverse Curve of Spee
arch wires
TREATMENT IN PERMANENT DENTITION-
-Same Principles
-Bite opening is done with Fixed Appliances like -
BEGG`S APPLIANCE EDGEWISE APPLIANCE

30. MYOFUNCTIONAL
APPLIANCES
DR. VIVEK P. SONI
PROF AND HEAD
DEPT. OF ORTHODONTICS
MYOFUNCTIONAL APPLIANCES

31. MYOFUNCTIONAL
APPLIANCES
 THEY ARE DEFINED AS LOOSE FITTING/ PASSIVE
APPLIANCES WHICH HARNESS THE NATURAL
FORCES OF THE OROFACIAL MUSCULATURE
THAT ARE TRANSMITTED TO THE TEETH AND
ALVEOLAR BONE IN A PRE-DETERMINED
DIRECTION THROUGH THE MEDIUM OF THE
APPLIANCE.
 “FUNCTIONAL APPLIANCES REFER TO A VARIETY
OF APPLIANCES DESIGNED TO ALTER THE
ARRANGEMENT OF VARIOUS MUSCLE GROUPS
THAT INFLUENCE THE FUNCTION AND POSITION
OF THE MANDIBLE IN ORDER TO TRANSMIT
FORCES TO THE DENTITION AND THE BASAL
BONE” – BISHARA S.E. (1989)

32. Activator Bionator Frankel’s functional regulator
Herbst Appliance
Jasper Jumper

33. CLASSIFICATION
1. ACCORDING TO PROFITT
• TOOTH BORNE-
ACTIVE PASSIVE
Eg. Elastic open activator, Eg. Activator, Bionator etc.
Bimler’s appliance etc.
TISSUE BORNE-
ACTIVE PASSIVE
Eg. Frankel’s functional regulator Eg. Oral screen, Lip bumper etc.

34. CLASSIFICATION
2.
 REMOVABLE (Activator, Bionator..)
 FIXED (Herbst, Jasper Jumper..)
 SEMIFIXED (Denholtz Appliance)
3.
 MYOTONIC (Activator, Bionator…)
 MYODYNAMIC (Elastic open activator, Bimler’s…)

35. CLASSIFICATION
4. ACCORDING TO T.M. GRABER
GROUP A- TOOTH SUPPORTED (Catlan’s app.)
GROUP B- TOOTH-TISSUE SUPPORTED (Activator)
GROUP C- VESTIBULAR POSITIONED (Frankel’s)
5. ACCORDING TO PETER VIG
CLASSICAL (ACTIVATOR, BIONATOR..)
HYBRID (DOUBLE SCREEN, FR HYBRID..)

36. MODE OF ACTION
 FUNCTIONAL MATRIX THEORY
(MELVIN MOSS)
 LATERAL PTERYGOID HYPOTHESIS
(MCNAMARA)
 SERVOSYSTEM THEORY
(PETROVIC)

37. OBJECTIVES
• In the natural dentition a functional equilibrium exists
under neurological control in response to the tactile stimuli
as teeth come in occlusion. A favorable equilibrium of
muscle forces between the tongue, lips and cheeks is
essential for normal function.
• The purpose of functional therapy is to change abberant
functional environment of the dentition and promote
normal function
• Functional therapy aims to unlock the malocclusion and
stimulate growth by applying favorable forces that enhance
skeletal development

38. THE ACTIVATOR

39. ACTIVATOR
Kingsley introduced the concept of “Jumping the
bite” for patients with mandibular retrusion. In 1879 devised a
vulcanite palatal plate to be used in patients having retruded
mandible. This vulcanite plate consisted of an anterior incline that
guided the mandible to a forward position when the patient closed
on it.
Hotz devised a `Vorbissplatte` which was a modified
form of Kinsley's plate. This was used to treat retrognathism
associated with lingually inclined lower incisors.
Pierre Robin devised an appliance called ‘Monobloc’
made up of single block of vulcanite. He used it to position the
mandible forward in patients with glossoptosis and severe mandible
forward it reduced the risk of airways obstruction.

40. HISTORY
Viggo Anderson in 1908 in Denmark developed a
loose fitting appliances which he first used on his daughter. He
made a modified Hawley type of retainer on the maxillary arch to
which he added a lower lingual horse shoe-shaped flange which
helped in positioning the mandible forward. He made this
appliance for his daughter who was going on a 3 month vacation.
On her return 3 months later he found a marked sagittal
correction and improvement of the facial profile. Andresen called
it the “ biomechanical working retainer”. Later Andresen moved
over to Norway and teamed up with Karl Haupl, a periodontist,
and brought about lot of changes in his device they called it
“Functional Jaw Orthopedics”.
As Andresen and Haupl were in Norway while
developing the appliance it was also called the “Norwegian
Appliance”. They later called it the “Activator” due to its ability
to activate muscle forces

41. INDICATIONS
- IT IS PRINCIPALLY A GROWTH MODULATION APPLIANCE TO BE
USED IN GROWING CHILDREN.WITH A FAVORABLE GROWTH
PATTERN.
-THE MAXILLARY AND MANDIBULAR TEETH SHOULD BE FAIRLY
WELL ALIGNED ON THE BASAL BONE.
-THE LOWER INCISORS SHOULD BE UPRIGHT ON THE BASAL
BONE.
IT CAN BE USED IN THE FOLLOWING CASES-
* Class II, Division 1 malocclusion
* Class II Division 2 malocclusion
* Class III Malocclusion
* Class I Open bite malocclusion.
* Class I deep bite malocclusion
* As a preliminary treatment before major fixed appliances therapy to
improve skeletal jaw relations.
* For Post-Treatment retention
* Children with lack of Vertical development tin lower facial height.

42. CONTRAINDICATIONS
The appliance is not used in correction of class I
problems of crowded teeth caused by disharmony between
tooth size and jaw size
The appliance is contraindicated in children with
excess lower facial height and extreme vertical mandibular
growth.
The appliance is not used in children whose lower
incisors are severely procumbent.
The appliance cannot be used in children with nasal
stenosis caused by structural problems within the nose or
chronic untreated allergy.
The appliance has limited application in non-growing
individuals .

43. MODE OF ACTION
• ACCORDING TO ANDRESEN AND HAUPL, THE ACTIVATOR
INDUCES A MUSCULOSKELETAL ADAPTATION BY
INTRODUCING A NEW PATTERN OF MANDIBULAR CLOSURE.
• MOST CHANGES ARE INSTIGATED BY HOLDING THE
MANDIBLE FORWARD (HYPERPROPULSION), STRETCHING THE
ELEVATOR MUSCLES OF MASTICATION, WHICH IN TURN
CONTRACT, THEREBY SETTING UP A MYOTACTIC REFLEX
• THIS REFLEX GENERATES A KINETIC ENERGY WHICH HAS A
RESTRAINING EFFECT ON THE MAXILLARY SKELETAL &
DENTO ALVEOLAR GROWTH.
• THIS IN TURN PRODUCES A RECIPROCAL INFLUENCE ON THE
MANDIBLE STIMULATING FORWARD MANDIBULAR
DEVELOPMENT.
• THERE IS ALSO A FAVORABLE CONDYLAR ADAPTATION BY
UPWARD AND BACKWARD GROWTH OF THE CONDYLE.

44. Construction bite
The construction bite is an intermaxillary wax record used to relate the mandible
to the maxilla in the three dimensions of space. They are used to reposition the
mandible in order to improve the skeletal inter-jaw relationship. The bite registration
involves repositioning the mandible in a forward direction as well as opening the bite
vertically. In most cases the mandible is advanced by 4-5 mm and the bite opened to
the extent 2-3 beyond the freeway space . The general consideration for construction
bite includes.
In case the overjet is too large , the forward positioning is done step wise
in 2-3 phases.
In case of forward positioning of the mandible by 7-8 mm, the vertical
openings should be slight to opening should be slight to moderate i.e 2-4 mm.
If the forward positioning is not more than 3-5 mm, then the vertical
opening can be 4-6 mm.

45. Low construction:-
Low construction bite with marked mandibular forward positioning:This kind of
construction bite is characterized by marked forward positioning of the
mandible but minimal vertical openings . A rule of thumb the anterior
advancement should not exceeded more than 3 mm posterior to the most
protrusive position. Vertically the openings in minimal and is within the limits
of the inter-occlussal clearance. This kind of activator constructed with
marked sagittal advancement but minimal vertical openings is called an `H
activator`. The h activator is indicated in a patient with class II . Division 1
Malocclusion having a horizontal growth pattern.

46. High construction bite with slight
mandibular forward positioning
The mandibles positioned anteriorly by 3-5 mm
only and the bite is opened vertically by 4-6mm or a maximum of 4mm beyond
the resting position . This kind of activator constructed with minimal sagittal
advancement but marked vertical opening is called a ‘V activator ~ The V
type of activator is indicated ib a class II< division 1 malocclusion having a
vertical growth pattern.

47. Construction bite without mandibular forward position:-
Sometimes a construction bite without forward positioning of
the mandible is made in cases such as deep bite ands opened bite.
Construction bite with opening posterior positioning of
the mandible:
In Class III malocclusion , the bite is taken after retruding the mandible to a
more posterior position. In addition , the bite is opened sufficiently to clear the
bite. In general a vertical opening of 5mm and a posterior positioning of about
2mm is required.

48. FABRICATION OF ACTIVATOR:-
Impressions:-
Impressions of the upper and lower arches are made to
construct 2 pairs of models:-
1. Studying models
2. Working models.

49. Bite registration:-
• The amount of sagittal and vertical advancement of the mandible is planned.
• A horse – shoe shaped wax block is prepared for insertion between the upper
and lower teeth. It should be 2-3 mm thicker than the planned vertical openings.
• The patients is made to sit in an upright relaxed and non-strained position
• The mandible is guided to the desired sagittal position. The operator should
merely guide the mandible using the thumb and forefinger. He should not use
pressure or force.
• The patients is asked to participate placements of mandible at the desired
sagittal position a few times before registration of the bite.
• The horse shoe shaped wax block is placed over the occlussal surface of the
lower cast and is gently pressed so as to form the indentations of the lower cast
and is gently pressed so as to form the indentions of the lower buccal teeth.
• The wax block is placed on the lower jaw and the patient is asked to bite at the
desired sagittal position
• It is then remove and placed on the models and checked.
• It found all right , it is chilled and once again tried on cast. the excess wax is
trimmed off.
• The hardened wax block is again tried in the patient's mouth.

50. Articulation of the model:
The wax bite registration is placed on the occlussal surface between
the upper and lower models. The models are then articulated in a reverses
direction so that the anterior teeth face the hinges . this kind of
articulation ensures sufficient access to the palatal surface of the upper
and lingual surface of lower models during the fabrications of the
appliance.
Preparation of the wire elements :-
The usual design requires an labial bow. The labial bow is made with 0.8 or 0.9
mm wire and consists of a horizontal section 2 vertical loops. The ends of the
vertical enter the acrylic body between the canine and deciduous first molar (or
first premolar).
The labial bow can be archived or passive.

51. Fabrication of the Arcylic portion :-
The appliance consists of 3 parts
Maxillary part
Mandibular part
Inter Occlussal part
The appliance can be fabricated by using either heat cure resin or cold
cure resin. In case of heat cure resin the models are first waxed and
then they are flasked .

52. Management of the Appliance :-
The patient should be sufficiently convinced about the
benefits he is going to derive.
The patients is also taught how to use place and remove the
appliance by himself.
Usually the patients is asked to wear the appliances for 2-3
hours a day during the day time for the first week.
During the second week the patient is asked to wear 3
hours during the day.
A trimming plan should be devolved based on the
individual needs of the patient . Some orthodontics prefer
the appliance to be worn for a week without any grinding
so that the patients can get used to it.

53. Trimming of the Activator :-
After fabrication of the activator it is usually found to fit
tightly as acrylic is interposed between the upper and lower occlussal
surfaces. Planned trimming of the appliance in tooth contact area is
carried out to bring an out dent alveolar changes so as to guide the teeth
in to good relation in all the 3 planes of space.
Selective trimming of acrylic is done in the direction of
tooth movement . the acrylic that transmit the desired force.
Approximate trimming can be done on the plaster casts However ,
final trimming should be done at the chair side.

54. TRIMMING of ACTIVATOR
Trimming of Activator for vertical control
Selective trimming of the activator can be done
to intrude or extrude the teeth.
Intrusion of teeth :- Intrusion of the incisors are
achieved by loading the incisal edge of these
teeth with acrylic. In case labial bows are
used , they should be placed below the area
of greatest convexity i.e. incisal to aid in the
intrusion fig (9.a)
In case intrusion of posteriors is needed then
only the cusp tips are loaded with acrylic.
The fosse and fissures are free of acrylic.
This applies a vertical intrusive force on the
molars

55. Extrusion of teeth :-
In case of extraction of the
incisors, the lingual surface is loaded
above the area greatest convexity in
the maxilla and below the area of
greatest convexity in the mandible .
The extrusive movements can be
enhanced by placing a labial
bow above the area of greatest
convexities in the gingival 1/3 of the labial
surface.
In case of molars ,
extrusion is brought about by loading
the lingual surface above the area of
greatest convexity in mandible.

56. TRIMMING OF THE
ACTIVATOR FOR
SAGITAL CONTROL
Selective trimming of the activator can be
done to protrude or ret rude the
anterior teeth and also to improve
the molar relation of the buccal
teeth.
Protrusion of incisors : in case the
incisors should be protruded,
lingual surface of the teeth is
loaded with acrylic and a passive
labial bow is given that is kept
away from teeth to prevent perioral
soft tissues contacting the teeth.
This acrylic loading of the lingual surface
can be of two types.

57. Entire lingual surface is loaded .
Since the area of contact is more
the force for proclination is also
low.
Only the incisal portion of the
lingual surface is loaded. As
acrylic contact is small greater
degree of force is generated to
tip the incisors labially.

58. Retrusion of incisors :
The acrylic is trimmed away from the lingual
surface and an active labial bow is used to
bring about Retrusion of the incisors.

59. Movement of posterior teeth in sagittal plane:
The teeth in the buccal segment can be moved mesially and distally to help in
treating Class II And Class III malocclusion .
In Class II malocclusion , the maxillary molars are allowed to move distally
while the mandibular molars are allowed to move mesially by loading the
maxillary mesiolinguial surface and mandibular distolingual surface. Fig

60. MOVEMNTS OF TEETH IN TRANSIVE PLANE
It is possible to trim the activator stimulate expansion of the buccal segment .
This is done by allowing the contact of the acrylic on the lingual surfaces of the
teeth to be moved transversely. But better expansion is possible by placing a
jack screw in the activator.

61. MODIFICATION OF
ACTIVATOR;-
Over the years a number of modification of the
classical activator have been describe.
The bow activator of A.M.schwarz:
The bow activator is a horizontal split activator having
a maxillary portion and a mandibular portion
connected together by an elastic bow . This kind of
modification allows step wise sagittal
advancements of the mandible by adjustments of
the bow . In addition this design allows certain
amount of transverse of the mandible .
The independents maxillary and the mandibular
portions can have a screw incorporated to allow
arch expansions.

62. Pretreatment picture & picture of appliances in the mouth

63. Post treatment picture

64. Wunderer`s modification :
This is an activator modification that is
mostly used in treatment of class III
malocclusion.
This type of activator is characterized by
maxillary and mandibular portions
connected by an anterior screw .
By opening the screw the maxillary portion is
moved anteriorly with a reciprocal
backward thrust on the mandibular portion
connected by an anterior screw .
By opening the screw the maxillary portion is
moved anteriorly with a recricipol backward
thrust on the mandibular portion.

65. THE REDUCED ACTIVATOR OR
CYBERNATOR OF SCHMUTH:_
This modification of the activator is proposed by Professor G.P.F Schmuth.
This Appliance resembles a bionator with the acrylic portion of the activator
reduced from the maxillary anterior area leaving a small flange of acrylic on the
palatal slopes . The Two halves may bee connected by an omega shaped palatal
slopes. THE two halves may be connected by an omega shaped palatal wire
similar to bionator.

66. The propulsor:-
This is an activator modification conceived by Muhlemann and refined by
Hotz. This appliance can be be said to be a hybrid appliance can that
combines the features of both the monoloc and the oral screen. The
propulsor is devoid of any wire components and consists of acrylic that
covers the maxillary buccal portion like an oral screen . This acrylic
portion extend in to the inner occlussal area and also as a lingual flange
that helps position the mandible forward.

67. CUTOUT OR PALATE FREE ACTIVATOR:-
This is a modification proposed by Metzelder to combine
the advantage of bionator and the Andresen's activator .The
Mandibular and the Anderson Activator .
The mandibular portion of the appliance resembles an
activator while the maxillary portion has acrylic covering
only the palatal aspect of the buccal teeth and a small part of
the adjoining gingival .
The palate thus remains free of acrylic thereby making the
appliances more convenient for longer hours. Due to the
greater amount of wearing time , success should be greater
with the palate free activator .
According to Dr. Klawas Metzelder the appliance is excellent in
mandibular positioning in T M J dysfunction cases

68. The Karwetzky modification :-
This consists of maxillary and mandibular plates joined by a `U`
bow in the region of the first permanent molar . The maxillary and
mandibular plates not only cover the lingual tissues and lingual aspect
of the teeth , it is also extends over the occlussal aspect of all teeth.

69. This type of activator allowsstepwise advancement of
the mandible by adjustment of the U loops.
The U loops has a largerandshorter arm . Based on
their placementpattern we can have three types of
Karwetzkyactivators.

70. Type I
This is used in the treatment of Class II Division 1. In this
modification , the larger lower leg is placed posterior . Thus When the
two arms of the U Bow are squeezed the lower plate moves sagitally
forwards.

71. Type II
This is used for the treatment of Class III malocclusion. In
this appliance the larger lower leg is placed anteriorly. Thus when the U
bow is squeezed the mandibular plate moves distally

72. Type III
They are used in bringing about asymmetric advancements of the
mandible . The U bow is attached anteriorly on one side and posterior on
the other side to allow asymmetric sagittal movements of the mandible

73. This activator allows mobility of the mandible and therefore makes the activator
more comfortable to wear . The appliances allows gradual and sequential
forward positioning of the lower jaw.
Herren`s modification of the Activator:-
Herren modified the activator in two ways:-
By over – compensating the ventral position of the mandible in the construction
wax bite.
By seating the appliances firmly against the maxillary dental arch by means of
clasps( arrow head, triangular or Jackson)

74. The construction bite is taken is a strong mandibular
protrusion. Herren recommends maximum forward
positioning of the mandible reaching sometimes the
feasible maximum.
This advanced position of the mandible causes retractor
muscles to try to bring mandible position . this causes a
backwardly directed force on the upper teeth and a mesial
directed force on the lower teeth.
Accordingly to Herren , with every 1mm increases of forward
position of the mandible, the sagittal force on the jaws will
increases by )) gm. A vertical openings of 2-4 mm is
recommended.

75. Triangular or Jackson clasps are used to firmly seat
the appliance to the maxillary dentition Expansion
screws can be used for expansion. Mobility of the
mandible is restricted by extending the lingual
flange of the activator as far as possible towards the
floor of the mouth.

76. THANK YOU