This document provides an overview of twin block therapy. It discusses the history, philosophy, design, construction, and stages of treatment using twin blocks. Twin blocks are functional appliances composed of separate upper and lower bite blocks. They are worn 24 hours a day to achieve rapid correction of malocclusions through forces transmitted to inclined planes covering the posterior teeth. Treatment typically involves an initial active phase followed by a support phase to stabilize results.

1. TWIN BLOCK
MOHAMED RAMEEZ
1

2. CONTENTS
 Introduction
 History
 Philosophy behind twin block therapy
 Angulation of inclined planes
 Diagnosis and treatment planning
 Indications and contraindications
 Bite registration
 Appliance design and construction
 Stages of treatment
2

3.  Treatment of class II div I malocclusion deep overbite
 Treatment in mixed dentition
 Combination therapy
 Twin block traction technique
 Treatment of anterior open bite and vertical growth patterns
 Treatment of class II division 2 malocclusion
 Treatment of class III malocclusion
3

4.  Treatment of facial asymmetry
 Magnetic twin blocks
 Adult treatment
 TMJ pain and dysfunction syndrome
 Flat earth concept of facial growth
 Growth response to twin block treatment
4

5. INTRODUCTION
 comprises of separate upper
and lower units which are not
joined together.
 simple bite blocks designed to
be worn 24 hours a day
 achieve rapid functional
correction of malocclusions by
transmitting favourable occlusal
forces to occlusal inclined
planes that cover all posterior
teeth.
5

6. HISTORY
 William J Clark was a Scottish
orthodontist
 Introduced twin block in the
year 1977
 First twin block was given to a
patient when aged 8 years 4
months
 Overjet reduced from 9mm to
4mm in 9 months
6

7. PHILOSOPHY BEHIND TWIN BLOCK
THERAPY
 Considerable forces are applied
through the muscles of
mastication to the teeth and
the underlying bony structures
to influence both the internal
and external structure of the
basal bone.
7

8.  It is this natural mechanism of
bone remodelling by occlusal
force vectors that forms the
basis of functional correction
by the Twin Block technique
Schwarz A.M (1932) tissue changes incidential to
orthodontics,Australian .J.orthod
8

9. ANGULATION OF INCLINED PLANES
 Earliest twin blocks were
constructed with inclined
planes articulated at 90 degrees
 Later altered to 45 degrees
 Finally changed to 70 degrees
which is widely used now
9

10. DIAGNOSIS AND TREATMENT PLANNING
 Clinical Guidelines
 Photographs
 Study models
 Radiographs
10

11. DIFFERENTIAL DIAGNOSIS
extraction or non extraction therapy
 Angle believed in accommodating all 32 teeth
 Tweed (1966) gained acceptance for premolar extraction
therapy
 Begg(1965)was a strong advocate of routine extraction of
premolars,and indeed in some cases advised the extraction
of all first molars in addition to first premolars
 Begg PR (1965) Begg orthodontic therapy and technique. WB Saunders company,
philadelphia
11

12.  Ricketts et al(1979) supported non extraction line of
treatment
 Ricketts recommends positioning the tip of lower incisor at
+1 to +3mm relative to the A-Pog line for the best aesthetic
result.
Ricketts, R M. et al (1979) bio progressive therapy..Am J orthod
12

13. Arch length discrepancy
 Richter scale is helpful in treatment planning to classify the
degree of difficulty of malocclusion as mild moderate or
severe in arch length discrepancy.
 Mild crowding is in range 1-3mm
 Moderate crowding is classified as 4-5mm
 Severe crowding is 6mm or more
13

14. INDICATIONS
 Treatment of uncrowded permanent
dentition with class II div 1
 Designed to correct class II skeletal
relationship, to correct molar relationship
& to correct overjet
 Patient should be in growing age for
favourable skeletal change
 Treatment of class II div 1 in mixed
dentition period
 Treatment of class II div 1 with anterior
open bite
 Treatment of class II div 1 with deep
overbite
 Treatment of class II div 2 malocclusion
 Treatment of class III malocclusion
14

15. CONTRAINDICATIONS
 Factors that are unfavourable for correction by twin blocks
include cases with vertical growth and crowding that may
require extractions
 Examination of profile : If profile doesn’t improve when
mandible is advanced that is a clear contraindication for
functional mandibular advancement
15

16. BITE REGISTRATION
 Upto 10 mm overjet : edge to edge
incisor relationship
 Overjet greater than 10mm: initial
advancement of 7mm or 8mm followed
by reactivation of the appliance after
occlusion had corrected to initial bite
registration
16

17. George bite gauge
 It has a millimetre gauge to measure
protrusive path of mandible
 Total protrusive movement is calculated by
first measuring the overjet in centric
occlusion and then in position of maximum
protrusion
 Bite forks comes in two sizes :2mm & 5mm
17

18. 18

19. Vertical activation
 An important principle is that the blocks should be thick enough to open
the bite slightly beyond freeway space
 On average bite blocks are not less than 5mm thick in the first premolar or
first deciduous molar region
 In treatment of anterior open bite it is necessary to register bite with a
greater interincisal clearance
19

20. SINGLE or PROGRESSIVE ACTIVATION
20
 Petrovic et al (1981): stepwise activation is better procedure
to promote orthopaedic lengthening of mandible
 Falke & Frankel (1989): reduced initial activation to 3mm
 De Vincenzo &winn (1989):differing results and reuire further
investigations

21.  Later on occlusal bite blocks where used to investigate the relative
effects of progressive activation compared to a single large
activation
 Concluded that there is no difference in either orthodontic
orthopaedic variables between progressive 3mm advancement and
a single advancement averaging 5-6mm
 Continuous advancement by 1mm activations show a diminished
but still significant response
Petrovic et al (1981)the final length of mandible? Is it genetically determined:craniofacial
biology,university of michigan
21

22. Control of vertical dimension
 Mechanism of control of vertical dimension differs in fixed and
functional therapy
 Fixed mechanics: teeth remain in occlusion during course of treatment
and the effect is limited to intrusion or extrusion of individual teeth to
increase or decrease overbite and level of occlusal plane
 Functional appliances: influence development in antero posterior and
vertical dimensions simultaneously, control of vertical dimension is
achieved by covering teeth in opposing arches & controlling the
intermaxillary space
22

23. Opening the bite
 In deep overbite cases check if profile improves when
mandible is postured downwards and forwards
 This confirms that bite should be opened by encouraging
eruption of posterior teeth to increase vertical dimension of
occlusion
23

24.  Occlusal tables or blocks placed between teeth encourage
ramus to grow vertically thus increase posterior facial height.
 At the same time occlusion is freed between posterior teeth
to encourage selective eruption of posterior teeth to
increase vertical dimension of occlusion in posterior region
24

25. Closing the bite
 Reduced overbite or anterior open bite is often related to
vertical facial growth pattern
 An acrylic block is designed to maintain the contact on
posterior teeth throughout treatment.
 This result in relative intrusion of posterior teeth while the
anterior teeth are free to erupt thereby
reducing anterior open bite
25

26. APPLIANCE DESIGN AND CONSTRUCTION
 Earliest twin blocks where designed with
 Occlusal bite blocks
 Midline screws to expand upper arch
 Clasps on upper molar and premolar
 Clasps on lower premolars
 Inter dental clasps on lower incisors
 Springs to move individual teeth and improve the
arch form as required
26

27. Standard twin blocks
 Labial bow
 Delta clasps
 Ball end clasps
 baseplate
27

28. Labial bow
 It tends to over correct incisor
angulation
 Used to upright severely
proclined incisors
 Earlier activation will act as a
brake to limit functional
correction by mandibular
advancement
28

29. Delta clasp
 Improves retention
 Reduce metal fatigue
 Minimal need for adjustment
29

30. Ball end clasp
 routinely placed mesial to lower canines
and in the upper premolar or deciduous
molar regions for interdental retention
from adjacent teeth
 Easy to fabricate
 Single gingival interference
 Less gingival irritation
 Indicated for additional retention
30

31. Base plate
31
 Appliance can be made of heat cure acrylic or cold cure acrylic
 Cold cure acrylic: convenient and speed are advantages but
compromises strength and accuracy
 Heat cure acrylic: additional strength and accuracy

32. Occlusal inclined plane- lower
 The inclined plane on lower bite block is angled from mesial
surface of second premolar or deciduous molar at 70
degrees to occlusal plane
 Buccolingually it covers occlusal surface of lower premolars
or deciduous molars to occlude with inclined plane on upper
twin block
 Bite blocks are thinner buccolingually in lower canine region
32

33. Occlusal inclined planes- upper
 Angled from mesial surface of upper second premolar to
mesial surface of upper first molar
 The flat occlusal portion then passes distally over the
remaining upper posterior teeth in a wedge shape, reducing
thickness as it extends distally
33

34. Position of inclined plane
 Angle stressed the importance of the first permanent molars
and described the development of key ridge in the first
molar region in response to functional forces applied to the
molars.
 Clark tested the response by moving the inclined planes
mesial to the first premolar region . this reduced both the
efficiency of the appliance and the response to mandibular
advancement.
34

35. STAGES OF TREATMENT
 Twin block treatment is described in two stages
35
Active phase Support phase

36. Stage 1: Active phase
 During the active phase, twin blocks are worn full time.
 The objective is to correct to the arch relationship in the
sagittal, vertical and transverse dimensions.
36

37. 37

38. Sequence of trimming of blocks
 In treatment of deep overbite,
bite blocks are trimmed
selectively to encourage
eruption of lower posterior
teeth to increase vertical
dimension and level the
occlusal plane
38

39. 39

40.  In anterior open bite and vertical growth patterns, posterior
bite block remains un reduced and intact throughout
treatment
 It results in intrusive effect of posterior teeth while anteriors
are free to erupt,which helps to increase the overbite and
bring the anterior teeth into occlusion
40

41.  At the end of the active phase, there should be a three point
contact in the incisor and molar region and the sagittal
relationship should be in a slightly overcorrected position.
 Aim is to achieve correction to class 1 occlusion with overjet
and overbite fully corrected
41

42. Stage 2: Support phase
 The objective of the support phase is to
retain the corrected incisor relationship until
the buccal segment occlusion is fully
established.
 The appliance of choice is an upper
removable appliance with anterior inclined
plane
42

43.  Lower twin block appliance is left out at this stage
and removal of posterior bite blocks allows
posterior teeth to erupt
 The upper and lower buccal teeth usually settle
into occlusion within 4 to 6 months.
 Full time wear is continued for another 3 to 6
months to allow time for internal bony
remodelling to support the corrected occlusion.
43

44. Retention
 Treatment is followed by retention with upper anterior
inclined plane appliance.
 Appliance wear is reduced to night time only when occlusion
is fully established.
 Good buccal segment occlusion is important to maintain the
correction of arch to arch relationships
44

45. Timetable of treatment
Average treatment time
 Active phase: avg. time 6-9 months to achieve full reduction of
overjet to a normal incisor relationship and to correct the distal
occlusion
 Support phase: 3-6 months for molar to erupt into occlusion
and for premolars to erupt after trimming of blocks.
 Retention: 9 months, reducing appliance wear when the
position is stabilised.
An avg. estimate of treatment time is 18 months, including
retention
45

46. Treatment of class II div I malocclusion
deep overbite
BITE REGISTRATION
 2mm vertical clearance between incisal
edges of upper and lower incisors
 Protrusive bite registered to reduce
overjet and distal occlusion on avg. by 5-
10mm on initial activation depending on
the freedom of movement in protrusive
function.
46

47. Appliance design
TWIN BLOCKS TO OPEN THE BITE
 Inclined planes must be clear of the
lower molars so that they can erupt
without obstruction
 Instructions should be given for
proper insertion and removal of
appliance
47

48. Full time appliance wear:
temporary fixation of twin blocks
 Unique advantage of twin block
 Guarantees full time wear of appliance at the start of
treatment
 The teeth should be fissure sealed and applied topical
fluoride as a preventive measure prior to fixation
48

49. Two alternative methods of fixation of twin blocks
 The appliance may be fixed to the teeth by spreading zinc
phosphate or zinc oxide on tooth bearing areas and seating
the appliance in place adhering to the teeth.
 Twin blocks may also be bonded directly on to teeth by
applying composite around clasps. this is useful in mixed
dentition when ball end clasps may be bonded directly to
deciduous molars to improve fixation
49

50. Soft tissue response
 As a result of altered muscle balance, significant changes in
facial appearance are seen within 2 or 3 weeks of starting
treatment with twin blocks
 As appliance is worn full time, even during eating, rapid soft
tissue adaptation occurs to assist the primary functions of
mastication and swallowing that necessitate an effective anterior
oral seal
50

51. Reactivation of twin blocks
 Reactivation of the twin block can be done as a simple chair side procedure by
the addition of cold cure acrylic to extend the anterior incline of the upper twin
block mesially as the clinician inserts the appliance to record a new protrusive
bite before the acrylic is fully set.
 No acrylic should be added to the distal incline of the lower twin block. Specially
in deep bite cases as extending the occlusal acrylic of the lower block distally will
prevent eruption of lower 1st molar.
51

52. 52
Indication for progressive reactivation of twin
blocks
 If overjet is greater than 10 mm
 In vertical growth pattern
 In adult treatment
 In treatment of TMJ dysfunction
 In any case where full correction of arch
relationships is not achieved after the initial
activation, an additional activation is necessary.

53. Treatment in mixed dentition
 The principles of treatment are
unchanged in mixed dentition,
although the response to
treatment may prove to be
slower depending on patients
rate of growth
Mcnamara JA Burden,W L(1993) orthodontic and
orthopaedic treatment in mixed dentition
53

54. Appliance design
 Similar design to permanent dentition
 Delta clasps are used on lower first or second deciduous molars
 Alternatively C clasp may be used for retention on deciduous molars
 Bonding composite on buccal surface of these teeth to get additional
undercut.
 Grinding retention grooves
 Using synthetic crown contours
54

55. Occluso-guide appliance
 It’s a pre formed mini positioner appliance
 It is designed to fit upper and lower teeth and
to act as a functional retainer by engaging the
teeth in edge to edge relationship in a slightly
open position with an inter incisal distance of
3mm
 Comes in different sizes
 Worn 1-2 hours per day and patient is
instructed to actively bite into the appliance
55

56. Combination therapy
 Combination therapy describes the combined use of
functional and fixed techniques in the management of
malocclusion
 Optimum timing of treatment is either in late mixed
dentition or early permanent dentition.
 In some cases twin blocks may be adapted for simultaneous
use with fixed appliances
56

57.  Twin block technique corrects skeletal discrepancies first,
both in the anteroposterior and vertical dimension followed
by alignment of the teeth
 The first phase phase ( skeletal correction ) may occur in
mixed dentition and the second phase( dental correction )
may follow when almost all permanent teeth has erupted.
57

58. Twin block traction technique
 When the response to functional correction is poor, the addition of
orthopaedic traction force may be considered.
 This method was limited to treatment of severe malocclusion, where
growth is unfavourable for conventional fixed or functional therapy
58

59. Indications
 In treatment of severe maxillary protrusion
 To control a vertical growth pattern by the addition of vertical
traction to intrude the upper posterior teeth
 In adult treatment where mandible growth cannot assist the
correction of severe malocclusion
59

60. The concorde facebow
 Cousins & Clark in 1965
 Concorde facebow apply intermaxillary and
extra oral traction to restrict maxillary
growth and to encourage mandibular
growth in combination with functional
mandibular protrusion
 Intermaxillary traction added to ensure
effectiveness of appliance
60

61. Treatment of anterior open bite and
vertical growth patterns
 Aetiology of the problem should be
diagnosed
 Prognosis for correction of anterior
open bite depends on the degree of
skeletal and soft tissue imbalance
 Direction of facial growth also
affects prognosis
61

62. Intra oral traction to close anterior openbite
 Intra oral elastics can be used to accelerate bite
closure as an efficient alternative to high pull extra
oral traction
 Introduced by Dr. Christine Mills in Vancouver
 The vertical elastics between upper and lower
appliances reinforces the intrusive effect of the bite
blocks
62

63. TREATMENT OF CLASS II DIV 2
 Retroclined upper incisors are
responsible for holding the mandible
in distal position in angles class II div
2 malocclusion
 Correction is done by advancing
mandible forward and downward
and encouraging lower molars to
erupt
 Upper incisors are advanced
63

64.  Construction bite is registered with
incisors in edge to edge occlusion
 Vertical development is the primary
factor in correction of class II div 2
malocclusion with minimum
advancement of mandible
64

65. Twin block sagittal appliance
 Witzig and spahl in 1987 used it for
anteroposterior development of arch
form
 Design of upper twin block is modified
by addition of two sagittal screws set
in palate for anteroposterior
development
 It can be used in lower arch too to
increase arch length
65

66. Combined transverse and sagittal development
 Three way screw
66
 Triple screw sagittal appliance

67. Topics to be covered in next session
 Treatment of class III malocclusion
 Management of crowding
 Treatment of facial asymmetry
 Magnetic twin blocks
 Adult treatment
 TMJ pain and dysfunction syndrome
 Flat earth concept of facial growth
 Growth response to twin block treatment
67

68. Thankyou
68

69. TWIN BLOCK
SECOND SESSION
69

70. TOPICS COVERED IN PREVIOUS SESSION
 Introduction
 History
 Philosophy behind twin block therapy
 Angulation of inclined planes
 Diagnosis and treatment planning
 Indications and contraindications
 Bite registration
 Appliance design and construction
 Stages of treatment
70

71. TOPICS COVERED IN PREVIOUS SESSION
 Treatment of class II div I malocclusion deep overbite
 Treatment in mixed dentition
 Combination therapy
 Twin block traction technique
 Treatment of anterior open bite and vertical growth patterns
 Treatment of class II division 2 malocclusion
71

72. TOPICS COVERED IN THIS SESSION
 Treatment of class III malocclusion
 Management of crowding
 Treatment of facial asymmetry
 Magnetic twin blocks
 Adult treatment
 TMJ pain and dysfunction syndrome
 Flat earth concept of facial growth
 Growth response to twin block treatment
72

73. Treatment of class III malocclusion:
Reverse twin blocks
 The position of bite blocks are
reversed compared to twin blocks for
class II treatment
 Designed to encourage maxillary
development by action of reverse
occlusal inclined planes cut at 70
degrees
73

74.  Occlusal forces exerted on
mandible is directed downwards
and backwards by the reverse
inclined planes.
74

75. Case selection
 Early treatment is often indicated
 Simplest clinical guideline is ability to achieve edge to edge upper
and lower incisors
 Prognosis is reduced when degree of skeletal discrepancy is more
 An initial RME is indicated in severe cases in younger patients
Mc Namara 1993
75

76. Bite registration
 Construction bite recorded with 2mm inter incisal clearance
with fully retruded position
 In brachyfacial class III additional vertical activation applied
to further open the bite by giving 4mm inter incisal clearance
76

77. Lip pads
 To enhance the forward movement of
upper labial segment
 It supports upper lip clear of the incisors
77

78. Reverse pull facial mask
 Adds additional component of
orthopaedic force to advance
maxilla by elastic traction
 In addition three-way
expansion is incorporated.
 Elastic force is increased
gradually
Delaire et al 1972, Petit 1982
78

79. 79

80. Management of crowding
 Interceptive treatment for arch development initiated as
early as possible
 Compatibility is checked by sliding lower model forward
80

81.  In permanent dentition fixed appliance treatment may
precede twin block treatment to correct an irregular arch
form
 In less crowded cases fixed appliances may be intergrated
with twinblocks
81

82. Treatment of facial asymmetry
 Sagital twin blocks give better
control for correction of dental
or facial asymmetry
82

83. Magnetic twin blocks
 Magnets in twin block
accelerate correction of arch
relationship
 Magnets often used are
samarium cobalt and
neodynium boron
83

84.  Attracting magnets : pulls the appliances together and
encourages the patient to occlude actively and consistently
in a forward position
 Accelerated correction of distal occlusion
 Can be used in correction of facial asymmetry
84

85.  Repelling magnets : The repelling magnetic force is
intended to apply additional stimulus to forward posture as
the patient closes into occlusion
 Used in twin blocks with less magnetic activation built into
occlusal inclined planes
85

86.  magnetic twin blocks cannot be reactivated by addition of
acrylic to the inclined planes as this deactivates the magnets.
 Screws may be needed on the bite blocks for progressive
activation of magnetic twin blocks.
86

87. Adult treatment
 Twin blocks can be used in treatment of adults if the skeletal
discrepancy is not severe.
 In severe skeletal discrepancies, twin blocks are
contraindicated and orthognathic surgery is the treatment of
choice in adult patients.
87

88. TMJ pain and dysfunction syndrome
 No dental condition is more distressing for a patient than
chronic tmj pain
 An excellent functional occlusion is the cornerstone of
treatment for temporomandibular dysfunction.
Ramfjord & ash (1983), Krough-Poulsen & Olsson (1968), Beyron (1954), Graf (1975)
88

89. Relief of pain- fundamentals of treatment
 Balanced occlusal support to relieve muscle spasm in initial stage of
treatment
 Removal of cuspal interferences causing mandibular displacement
on closure
 Good vertical support for the joints to function freely without
compression of articular disc
 Freedom of movement with cuspal guidance and incisal guidance
when mandible moves from centric occlusion
 Tripoding of occlusal contacts in final balanced occlusion
89

90. The reciprocal click
 A clicking joint is indicative of displacement of the articular disc off
the head of the condyle .
 the timing of click on opening is significant in the prognosis for
resolution:
 1. early opening click up to 22 mm opening are usually easy to
resolve
 2. mid opening click 22-35mm of opening are moderate to
resolve
 3. late opening clicks over 35mm of opening are difficult to
resolve.
90

91. Temporomandibular joint therapy
 The goals of therapy are:
 Relieve the pain caused by distal displacement of the condyle
 Retrain the muscles to a healthy pattern
 Recapture the disc when possible by advancing the displaced
condyle
 Move the teeth that are causing occlusal imbalance and
mandibular misguidance
 Increase the vertical dimension to reduce deep overbite
91

92. Twin blocks in temporomandibular joint
therapy
 Twin blocks achieve the following objectives
 1. Pain is relieved within 4 days of fitting twin blocks.
 2. Facial balance is improved and muscle spasm relieved.
 3. The disk is recaptured by posturing the mandible downward
and forward to advance the condyles.
 4. Rather than acting as a passive splint, twin blocks can move
teeth that are causing occlusal imbalance.
 5. The upper block may be trimmed selectively over the lower
first molar only, using molar bands with vertical elastics to
accelerate eruption.
92

93. Flat earth concept of facial growth
 Understanding the concept of volumetric growth of the face
is as important as realising that earth is round and not flat
 Limitations of cephalometric analysis are mainly due to the
conversion of a 3D structure to a 2D image
93

94.  For example; given the three
dimensional shape of mandible and its
semi elliptical morphology,
measurement from condyle to condyle
is the meaningful representation of
mandibular periphery than the midline
projection of mandibular length from
Condylion to pogonion
94

95.  Measurement of peripheral length of mandible on dry skull
using flexible ruler indicates that peripheral length on each
side is 20% greater than the projected cephalometric linear
distance from pogonion to Condylion.
95

96.  The mathematical formula
for the expansion of an
object relating to percentage
change is expressed as:
96
 Any linear values multiplied by
three to convert to volumetric
values
 1% of increase in radius of sphere
increases the volume by 3%
 Head is more closely related to a
sphere or an ellipsoid than the
projected two dimensional
cephalometric image

97.  A cephalometric radiograph is used to interpolate the three
dimensional changes in specific areas of craniofacial complex
 A slice of sphere is an appropriate model to illustrate this
mathematical principle
 The volume of slice of sphere= angle/360o x 4/3#r3
 The same principle can be applied to interpret volumetric
changes in the middle third and lower third of the face
97

98. Response to twin block treatment
 Harvold demonstrated in animal experiments that when the
mandible is advanced, a "tension zone" is created above and
behind the condyle. This is an area of intense cellular activity
quickly invaded by proliferating connective tissue and blood
capillaries
 From animal studies, it may be deduced that retraction of
the condyle results in compression of connective tissue and
blood vessels and the resulting ischaemia is the principal
cause of pain.
 This change in muscle activity is described by McNamara as
the "pterygoid response"
98

99. Conclusion
In the pursuit of ideals in Orthodontics, facial balance and
harmony are of equal importance to ideal and perfect
occlusion.
Twin blocks are extremely patient and operator friendly
functional appliances.
They have the gift of versatility of design, which allows their use
in a variety of clinical situations to effectively correct different
types of malocclusions.
99

100. References
 Twin block functional therapy-William j clark
 Tan et al,A preliminary report of a new design of cast metal fixed twin-block
appliance, Journal of Onhodottíics, Vol. 34. 2007, 213-219
 Woodside DG (1977) The activator. In: Graber TM, Neumann B, editors.
Removable Orthodontic Appliances. Philadelphia: Saunders; pp. 269-336.
 McNamara JA. Neuromuscular and skeletal adaptations to altered function in
orofacial region. AJO 1973)
 Dixon et al,Mandibular incisal edge demineralization and caries associated with
Twin Block appliance design, Journal of Orilwitonfics, Vol. 32. 2005, 3 10
100

101. ACKNOWLEDGEMENT
 DR. RAJKUMAR. S.ALLE
 DR. SHWETHA.G.S
 DR. SHASHI KUMAR.H.C
 DR. SUMA.T
 DR. LOKESH.N.K
 DR. KIRAN.H
 DR. SIDHARTH ARYA
 DR. DHARMESH.H.S
 DR.BHARATI
 DR.FAISAL ARSHAD
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102. Thankyou
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