2. CONTENTS
Introduction
Growth of mandible
Growth rotations
A) BJORK STUDY
B) BJORK & SKEILLER
C) F.F. SCHUDY
D) DIBBET’S CONCEPT
E) PROFFIT’S CONCEPT
Maxillary growth rotations
Jaw relation and tooth eruption
Mutual relationship of rotating jaw bases
Comparison of short and long faces
Conclusion
References
3. Introduction
The phrase growth rotation was introduced in 1995
by Prof. ARNE BJORK
He is considered as the father of implant
radiography.
Cephalometric implant radiography has
revolutionized the growth studies in the field of
orthodontics.
3
4. Growth and inclination of jaw bases is unique and no two individuals
are alike.
Jaw rotations can be easily manipulated by means of functional and
orthopedic devices
Certain extreme rotations are very difficult to treat and need surgical
intervention
4
6. Corpus of the mandible is a direct
structural counterpart to the
maxillary corpus.
Ramus is related to the pharyngeal
space and middle cranial fossa.
Ramus bridges the middle cranial
fossa and the corpus in proper
relation with the cranial floor
articulation on one side and
maxillary corpus on other side
6
7. 7
Mandible gets progressively relocated
posteriorly superiorly by combination of
resorption and deposition.
The ramus width increases to
accommodate the increase in middle
cranial fossa and the pharynx
These changes lead to change in
orientation of the mandible leading to
ROTATION OF THE MANDIBLE.
Essentials of Facial Growth – Donald H Enlow
8. BJORK STUDY (1969)
Started his study in 1951
Sample size of 100 children between the
age group of 4 – 24 yrs.
Bjork studied mandibular inclinations by
placing implants at various sites of
mandible
The sites of growth and resorption in
individual jaws , variation in direction and
intensity were examined
8
Prediction of mandibular growth rotation, Bjork. A (Am. J. Orthodontics
June 1969)
10. According to the type of rotation and the centre of rotation the
growth of the mandible can be divided into
◦ Forward rotation
◦ Type I
◦ Type II
◦ Type III
◦ Backward rotation
◦ Type I
◦ Type II
10
Prediction of mandibular growth rotation, Bjork.A. Am. J. Orthodontics
June 1969
MANDIBULAR INCLINATIONS
BASED ON CENTRE OF ROTATION
11. Forward rotation type I
Centre of rotation is in the joint
Deep bite is seen
Decreased lower anterior facial
height
Etiology : Powerful muscular
pressure , Occlusal imbalance due
to teeth loss
11
12. Forward rotation type II
Centre of rotation is at the incisal edges
of the lower incisors.
Increased posterior facial height
Posterior facial height can increase due to
:
Lowering of the middle cranial fossa
lowering condylar fossa
Increased ramal height
12
13. Forward rotation type III
In cases of increased overjet the centre
of rotation is displaced to the premolars
There is decreased anterior lower facial
height
Increased posterior facial height
Skeletal deep bite is seen
Mandibular symphysis swings forward
– prominent chin
13
14. Backward rotation type I
Centre of rotation at the joint.
Seen where the bite is raised by
orthodontic treatment increasing the
lower anterior facial height.
Raised middle cranial fossa
raising mandible increasing anterior
facial height
14
15. Backward rotation type II
Centre of rotation is at the most
distally occluding molar.
Growth at the condyles is in the
sagittal direction.
Mandible increases in length and is
carried forward more due to its
muscles and ligament attachments.
15
16. Symphysis is swung backward, chin goes
below the face.
Skeletal open bite is seen.
Incompetent lips
Lower incisors retrocline and meet the upper
incisors.
Molars and premolars of mandible are
inclined forward.
16
17. Structural Signs
Bjork gave seven structural signs to find the direction of mandibular growth.
1. Condylar inclination
2. Mandibular canal curvature
3. Lower border of mandible shape (Antigonial notch)
4. Symphysis inclination
5. Interincisal inclination
6. Interpremolar or Intermolar angle
7. Anterior lower face height
17
18. CONDYLAR INCLINATION
Forward or backward inclination the
condylar head is characteristic sign.
In forward growing mandible condyle is
upright compared to a backward
growing mandible in which it is inclined
backward.
Difficult to identify on the lateral
cephalogram.
18
19. MANDIBULAR CANAL
In vertical growing mandible the curvature of the canal is more than
that of the mandibular contour.
Where as in case of horizontal growers the canal may be flat or may
even be curved in opposite direction.
19
Mandibular canal inclination
horizontal vertical
20. SHAPE OF THE LOWER
BORDER OF MANDIBLE
In vertical growers there is an
increased deposition below the
symphysis , resorption at the
angle producing a characteristic
concavity.
In horizontal growers the anterior
rounding is absent so the
concavity of the lower border is
absent.
20
21. INCLINATION OF THE SYMPHYSIS
In vertical growers chin swings forward to become prominent.
In horizontal growers symphysis is swung backward causing a
receding chin.
21
22. INTERINCISAL ANGLE
Interincisal angle is almost
constant showing that the lower
incisors is related functionally to
the upper incisors
In vertical growers angle in less
In horizontal growers there is an
increased interincisal angle
INTERMOLAR ANGLE
In case of forward rotation the
molars get more upright increasing
the intermolar and interpremolar
angle
In case of backward rotation the
molars become mesially tipped
hence decreasing the intermolar
and interpremolar angle
22
23. LOWER FACE HEIGHT
Is increased in case of vertical growth pattern while is less
in case of a horizontal growth pattern
23
LOWER ANTERIOR FACIAL HEIGHT
24. BJORK AND SKIELLER
Bjork and Skeiller together carried out extensive implant studies
and introduce various terminologies to understand the rotational
pattern of mandible.
Divided the mandibular rotations into three components
◦ Total rotation
◦ Matrix rotation
◦ Intramatrix rotation
24
Prediction of mandibular growth rotation evaluated from a longitudinal implant sample –
Skieller, Bjork and Linde-Hansen ( AJO V. 86 N.5 1984)
26. Total Rotation
Is the rotation of the mandibular corpus
Is measured as change in inclination of a reference line or a
implant line in the mandibular corpus relative to the anterior
cranial base.
If line anteriorly rotate towards the face then is known as
forward rotating .
26
Prediction of mandibular growth rotation evaluated from a longitudinal implant
sample – Skieller, Bjork and Linde-Hansen ( AJO V. 86 N.5 1984)
27. Matrix rotation
Is rotation of soft tissue matrix of the
mandible relative to the cranial base.
Is shown by a tangential mandibular line.
It can rotate forward and backward in the
same patient with condyles as the centre
of rotation and is described by the term
pendulum movement.
27
Prediction of mandibular growth rotation evaluated from a longitudinal implant sample –
Skieller, Bjork and Linde-Hansen ( AJO V. 86 N.5 1984)
28. Intramatrix rotation
Is the rotation of the mandibular corpus within its soft tissue
matrix
The difference between the total rotation and the matrix rotation
It is an expression of remodelling of the lower border of the
mandible.
It is found out by the change in inclination of an implant line or
reference line in the mandibular corpus to the tangential
mandibular line.
28
Prediction of mandibular growth rotation evaluated from a longitudinal implant sample –
Skieller, Bjork and Linde-Hansen ( AJO V. 86 N.5 1984)
30. DIBBETS CONCEPT (1985)
Dibbets re-examined the concept of intramatrix rotation as defined
by Bjork and Skeiller in 1983.
Gave a third interpretation which is based on two hypothetical
divergent patterns of growth :
a) One pattern postulates condylar growth as a segment of a circle
with its centre at the chin. The whole mandible would then rotate
around itself within its periosteal contours, resulting in
“intramatrix rotation” without enlargment of the mandible
30
Dibbets JMH. Puzzle of growth rotation, AJO-DO 1985
32. •He showed that external configuration of the mandible need not
change its form or position within the head to allow intra matrix
rotation
• The mandibular periosteal contours may be like a frame bordering
a painting. The painting may be rotated within the frame, but the
external outline, configuration, and dimension do not change
32
33. b) A linear growth curve of the condyle, without any
“intramatrix rotation” and maximum enlargement of the
mandible
Most of the children will be observed to fall in between
these two postulated extreme patterns
33
34. COUNTERBALANCING ROTATION
Comparing the extremes, it may be deduced that “intramatrix
rotation” is capable of offsetting growth and of neutralizing growth
to a substantial degree
The process involves a selective remodeling of the mandible.
This selective remodeling at the lower border is termed as the
“counterbalancing rotation”
This counterbalancing mechanism neutralizes effect of growth of
the condylar cartilage. 34
38. CONTENT
Growth rotations
A) F.F. SCHUDY
B) PROFFIT’S CONCEPT
Maxillary growth rotations
Jaw relation and tooth eruption
Mutual relationship of rotating jaw bases
Comparison of short and long faces
Conclusion
References
38
41. F.F. SCHUDY (1965)
CLOCKWISE ROTATION: ( as viewed from
the patient right side)
Jaw bones or mandible grows downwards and
backwards result of excessive vertical growth
The point of rotation is at the condyles.
Vertical growth in the molar region is greater
than at the condyles.
Mandible rotates clockwise resulting in more
anterior facial height and less horizontal change
of chin.
Extreme cases cause open bites. 41
42. There are four vertical growth
elements which increase the facial
height:-
I. Anterior growth of nasion.
II. Corpus of maxilla getting palatal
plane down.
III. Eruption of maxillary molars.
IV. Eruption of mandibular molars.
42
43. • When growth at A exceeds sum of
I,II,III,&IV. the mandibular plane becomes
flatter & Pog moves forward more than
nasion.
• When growth of the sum of I,II,III,&IV
exceeds A, Pog will move backward with
relation to nasion & mandibular plane will
become steeper.
*When growth at A equals the sum of
I,II,III, & IV, the mandibular plane moves
down in a parallel manner.
43
44. COUNTERCLOCKWISE
ROTATION
Bone grows upward and forward result
in
More anterior growth than posterior
growth.
Forward movement of pogonion &
increase in facial angle
Flattening of mandibular plane.
Decreased gonial angle.
Short face
44
45. Clinical Implication
If Vertical Growth deficient , simulation of vertical growth can be
done and if vertical growth excessive we try to inhibit it
The mandible should not considered as a single entity but rather as
4 entity
1. growth of condyle and ramus 2. of the corpus 3. Posterior
alveolar process 4. Anterior alveolar process
He cocluded that mandibular growth is the principal determining
factor of facial morphology
45
46. PROFFIT’S DESCRIPTION OF
ROTATION
Proffit coined different terminologies to explain growth rotation of
mandible
Total rotation
Internal rotation
External rotation
Total rotation : rotation of mandibular plane relative to cranial base
Total rotation = Internal Rotation - External rotation
46
Contemporary orthodontics – W.R. Proffit 5TH edition.
47. There are two contributions to
internal rotation
A) Matrix rotation (hinge rotation)
rotation around the condyle
B) Intra matrix rotation
rotation centered within the body of
the mandible
47
48. 15% of Internal
rotation
External Rotation(
Rotation due to surface
changes)
Internal
Rotation(rotation
occurs in the core of
jaw)
Rotation depending upon location of growth
48
Matrix
Rotation
(25%)
Intramatrix
Rotation
(75%)
Remaining parts of
mandible like alveolar
process ,muscular
process, condylar
process
Total Rotation 3-4%
11-12 % External
Rotation
50. CLINICAL IMPLICATION
1) Short face type
They are characterized by short anterior lower face height with
excessive forward rotation of the mandible due to increase in the
normal internal rotation and decrease in external compensation
This results in:
• Nearly horizontal palatal plane
• Low mandiular plane angle
• Large gonial angle
• Deep bite
• Crowded incisors
50
Contemporary orthodontics – W.R. Proffit 5TH edition.
51. 2) Long face type
• Characterized by increased anterior and total face height and
results from a lack of the normal forward internal
rotation or even a backward internal rotation. The internal
rotation in turn is primarily centered at the condyle
This results in:
• Palatal plane rotates down
posteriorly.
• Mandible shows an opposite backward
rotation.
• Increase in mandibular plane angle
• Associated with open bite
51
Contemporary orthodontics – W.R. Proffit 5TH edition.
52. GROWTH ROTATION OF MAXILLA
Maxilla undergoes extensive remodelling and displacements when
subjected to various functional demands.
Growth vector of maxillary growth is in anterior and inferior direction.
Due to varying growth activities of middle cranial fossa, the sutural
attachments of midface and surface remodelling, the maxilla tends to
get rotated by displacement
52
53. Growth of maxilla occurs by two
ways
Passive displacement - in primary
dentition period
Active growth is by surface
remodeling
53
55. Primary Displacement - The
whole nasomaxillary complex is
displaced with conjunction in it’s
own growth
Secondary Displacement –
Results from growth of other
bones and their soft tissue matrix
55
56. Drifts of teeth
As the maxilla and mandible enlarges ,
dentition drifts Horizontally and vertically
The whole tooth and its socket move
56
57. Nasal palatal remodelling
The balance between greater and lesser
amounts of remodelling in the posterior &
anterior parts of the maxilla is the response
to clockwise /counterclockwise rotatory
displacement of middle cranial fossa .
Compensatory remodelling rotation of the
nasomaxillary complex sustains its proper
position
Remodelling also occurs as bones assume
new positions with expansion of the soft
tissue matrix
57
58. In 1997 Bjork and Skeiller studied growth
rotation with help of implant
58
Inferior to nasal spine
Zygomatic process of
maxilla (lateral implant)
At the border between the
hard palate and the alveolar
process medial to first molar
3 sites of implant
placement as follows
59. Bjork and Skeiller introduced various terminologies to describe
growth rotation of maxilla:
INTERNAL ROTATION -Implants placed on maxillary alveolar
process show that the core of the maxilla undergoes a small and
variable degree of rotation - forward or backward .
EXTERNAL ROTATION -Varying degree of resorption on nasal
side and deposition on palatal side, also varying amount of eruption
of incisors and molars .
59
Contemporary orthodontics – W.R. Proffit 5TH edition.
60. Forward growth rotation
Due to excessive internal rotation or
lack of normal compensatory external
rotation or a combination of both.
Maxilla is inclined upward and
forward, anterior end is tipped up this
is also called as ante inclination
/Pseudo Protrusion as coined by
Schwarz
60
61. BACKWARD GROWTH ROTATION
61
Downward and backward tipping of the
anterior end of the palatal plane and the
maxillary base.
Jaw bases are translated posteriorly and
the upper incisors appear to tip
lingually (retroclination)
62. CLINICAL IMPLICATION
According to Linder-Aronson, Lowe and Woodside (1986) various
environmental factors influences such as neuromuscular dysfunction,
occlusal forces, gravity and nasorespiratory malfunction can modify
maxilla inclination
Mouth breathers Upward and forward tipping of the anterior part
of maxilla.
Vertical growing faces Downward and backward tipping of
anterior part of maxilla.
The inclination of maxilla can be influenced by both fixed orthopedic
and functional therapeutic techniques.
62
Dento facial orthopedics with functional appliances
Thomas M Graber Thomas Rakosi Alexandre G. Petrovic
2nd edition
63. Growth of the mandible away from the maxilla creates a space into
which teeth erupt.
Rotational pattern of jaw growth influences the magnitude of tooth
eruption
PATH OF ERUPTION OF MAXILLARY TEETH: Downward and
forward
Forward rotation of maxilla tip incisors forward
Backward rotation of maxilla relatively upright the incisors
63
Contemporary orthodontics – W.R. Proffit 5TH edition.
JAW ROTATION AND TOOTH
ERUPTION
64. PATH OF ERUPTION OF
MANDIBULAR TEETH:
Upward and forward
Normal internal rotation of the mandible
carries the jaw upward in front
This rotation alters eruption path of
incisors tending to direct them more
posteriorly.
As the internal jaw relation tends to
upright the incisors, molars migrate
further mesially and thus arch length
decreases
64
65. MUTUAL RELATIONSHIP OF
ROTATING JAW BASES
Maxillary and mandibular rotations were demonstrated to have a
major role in mutual adjustment of both the jaws.
Four types of mutual rotation of jaw bases were proposed by
Lavergne and Gasson (1982)
65
Lavergne and Gasson. Analysis and classification of the rotational growth pattern
without the use of implants. BJO 1982;9.
69. Mandibular Rotation and Remodeling
Changes during Early Childhood
Sample included 43 males and 43 females having class I and
Class II molar relationship
Lateral cephalograms at three developmental stages
late primary (T1: 5.7y), early mixed (T2: 8.4y), and full
permanent dentition (T3: 15.4y).
Cranial base and mandibular superimpositions were performed
with the use of natural reference structures
CONCLUSION:
Although significant amounts of true mandibular rotation and
angular remodeling occur during childhood and adolescence, true
rotation is greatest during the transition from late primary to early
mixed dentition.
69
WANG, BUSCHANG, BEHRENTS
Angle Orthodontist, Vol 79, No 2, 2009
71. Mandibular Growth Rotation
Effects on Post-retention Stability
of Mandibular Incisor Alignment
71
Piotr Fudalej; Jon Artun Angle Orthodontist, Vol 77, No 2, 2007
Angle Orthod. 2013;83:29–35
To test the hypotheses that pronounced forward and backward mandibular
growth rotation may be risk factors for postretention relapse of mandibular
incisor alignment, and that morphologic parameters at adolescence may be
predictive of the remaining type of mandibular growth.
Cephalograms and study models were made before (T1) and after (T2)
active treatment and at a minimum of 10 years postretention (T3) of three
groups of orthodontic patients with acceptable occlusion at the time of
appliance removal.
The groups were short facial height ,normal facial height ,long facial height
72. Conclusion
•High-angled and low-angled facial patterns at the time of appliance
removal are not associated with increased risk of postretention
relapse of mandibular incisor malalignment in adolescent
orthodontic patients, and are poor predictors of type of postretention
growth.
72
73. How does tooth eruption relate to vertical mandibular
growth displacement?
Liu and Buschang Am J Orthod DentofacialOrthop 2011;139:745-51
Rates of vertical mandibular displacement and eruption
accelerated between 10 and 12 years of age, peaked at
approximately 12 years of age, and decelerated between 12 and
15 years of age.
CONCLUSION
Rates of mandibular dental eruption were closely associated
with vertical mandibular growth displacement in French-
Canadian girls.
Low associations between mandibular incisor eruption and
mandibular growth suggest only limited compensatory potential.
73
75. Method by Todd, Ram S Nanda, Frans
Currier, Surendar K Nanda
The purpose of this study was to determine whether symphysis
morphology could be used as a predictor of direction of mandibular
growth rotation.
They used lateral X-rays of 115 adults for this study.
Men possess a stronger relationship between symphyseal morphology
and the direction of mandibular growth when compared to women.
Symphysis ratio was strongly related to the direction of mandibular
growth in men.
75
76. Women also showed the same
relationship as the men between
symphysis height, depth, ratio, and
angle to the direction of the
mandibular growth.
Symphysis showed continuous
change up to adulthood in both male
and female, with the female subjects
having smaller and earlier changes
occurring than compared to male.
76
78. CONCLUSION
The ability of an orthodontist to predict future mandibular growth
would greatly aid in the diagnosis and treatment planning.
Better therapeutic decisions could be made regarding timing and
length of the treatment, appliance selection, extraction pattern and
possible need for surgery.
And with it’s knowledge, therapy could be truly tailored to the
individual with the possibility of obtaining optimal results in shorter
period of time.
78
79. References:
Contemporary orthodontics – W.R. Proffit. 5th edition
Dento facial orthopedics with functional appliances -Thomas M Graber,
Thomas Rakosi, Alexandre G. Petrovic - 2nd edition
Essentials of facial growth – D.H. Enlow. 3rd edition
Prediction of mandibular growth rotation – A. Bjork, AJO, June 1969,
pg. 585-599.
79
80. References:
Prediction of mandibular growth rotation evaluated from a longitudinal
implant sample. Skieller, Bjork, Linde-Hansen, AJO-DO 1984; 371-85
F F Schudy. The rotation of the mandible resulting from growth: its
implications in orthodontic treatment - Angle Orthod 1965.
The puzzle of growth rotation – J.M.H. Dibbets, AJO, June 1985, pg.
473-480.
80
81. 81
References:
Wang, Buschang, Behrents. Mandibular Rotation and Remodeling
Changes during Early Childhood. Angle Orthodontist, Vol 79, No 2,
2009
Piotr Fudalej; Jon Artun. Mandibular Growth Rotation Effects on Post-
retention Stability of Mandibular Incisor Alignment. Angle Orthod.
2013;83:29–35
Liu and Buschang. How does tooth eruption relate to vertical
mandibular growth displacement? Am J Orthod Dentofacial Orthop
2011;139:745-51
Pollard et al. Relapse of orthodontically corrected deep bites in
accordance with growth pattern. Am J Orthod Dentofacial Orthop
2012;141:477-83
Schudy states that mandible should not be considered as a single entity, but rather as four entities
Growth of the condyle and ramus
Growth of the corpus
Growth of the posterior alveolar process
Growth of the anterior alveloar process
Schwarz coined these terms as anteinclination and pseudoprotrusion.
