Growth rotations /certified fixed orthodontic courses by Indian dental academy
INDIAN DENTAL ACADEMY
Leader in continuing dental education
The term growth rotation was introduced in 1955 by
Bjork. He used it to describe a particular phenomenon,
occurring during the growth of head.
At the time when x-ray cephalometry was introduced
GROWTH CHANGES in the form of face and head.
These conventional x-ray measurement /tracings
showed comparatively small changes with age in the facial
form and intermaxillary relationship.
A series of questions arose
Is that intermaxillary relation static throughout the
period of growth?
(ii) If the facial form remain static with age then is the
treatment of malocclusion independent of age, sex or
The answer was NO
It was at this time when longitudinal studies with
cephalometry were conducted and the concept of
INDIVIDUAL DIFFERENCES in the development of
facial form and intermaxillary relations were recognized.
And it was Bjork who used metallic implants as
markers in the jaws from which he located,
1. Sites of growth and resorption in the individual jaws
and examined individual variation in direction &
intensity of growth.
2. The mechanisms underlying changes in the
intermaxillary relationship during growth.
Until Bjork's studies, the extent to which both the
maxilla and mandible rotate during growth was not
Bjork identified stable points
in the mandible and placed
implants on those points.
The core of the
mandible is the bone that
surround the inferior alveolar
The rest of the
mandible consists of several
He identified that the mandibular canal is not remodeled
to the same extent as the outer surface of the jaw and the
trabaculae related to canal (Core of the mandible) are
therefore relatively stationary.
Also the lower border of the developing molar tooth germ
(before the roots begins to form) appears to be fairly stable
point and serve as natural reference structure in the growth
analysis of the mandible .
In 1951, Bjork conducted a mixed longitudinal study by
the use of these implants in about 100 children of each sex
covering the age period from 4 to 24 years.
By super imposing consecutive tracings, he concluded that
1. Marked resorption in the gonial region.
2. Apposition in the posterior and lower border of the
The pattern of mandibular growth rotation is generally
UPWARD & FORWARD curving growth whose degree of
rotation is being masked by resorption on the lower aspect of
the gonial angle and apposition below the symphysis.
Thus these two factors the upward +forward growth
rotations of 15 degrees to 2-4 degrees.
With the conventional examination of the cephalametric
radiograph (base of the mandible), TMJ was considered as the
center of rotation of the mandible.
Bjork with the implant method recognized various types of
rotation with varying centres of rotation.
BROADLY CLASSIFIED INTO
Inciscal edge of
Normal AFH Marked
(i). Lowering at middle
cranial fossa, lowering
the condylar fossa
(ii). Vertical growth at
the mandibular condyle
At the level of
In anamolous occlusion
of anterior e.g.
Occlusal imbalance due
to loss of teeth /
Less frequent than forward rotations
1. Raising of bite by
2. Flattening of cranial
Growth in the saggital Basal open bite
direction at the
Type II in both types of rotation is due to different condylar
Vertical direction of condylar
Saggital direction of condylar
Lowering of mandible
Mandible grows in the direction of
This lowering of mandible in turn
takes place as forward rotation
due to the muscular and
Due to attachments of muscles
and ligaments the mandible is
TYPE - I
TYPE - II
TYPE - I
TYPE - III
TYPE - II
In Type II Backward rotation COR at the distal occluding
Symphysis is swung backward
Chin is drawn below the face
Soft tissue do not follow the bony chin
Characteristic double chin is formed
Inclination of teeth: (Bjork & Skieller) (lower)
The inclination of teeth, is also greatly influenced by
rotation of the lower jaw.
Incisors: Irrespective of jaw rotation the lower incisors are
functionally related to the upper incisors & follow the upper
Dentoalvealar proclination of lower anteriors
Mesial path of eruption leading to crowding (packing)
Dentoalvealar retroclination of lower anteriors
Lower posterior teeth
(than normal) lower posteriors in
relation to the upper posteriors.
Increase in interpremolar and intermolar angles
and the vice versa for backward rotations.
Bjork also named 7 structural signs of extreme growth
rotations. He also stated these signs will help in a clinical
aspect to detect extreme types of mandibular rotation,
occurring during growth.
1. Inclination of the condylar head.
2. Curvature of the mandibular canal.
3. Shape of the lower border of the mandible
4. Inclination of the symphysis.
5. Inter Incisal Angle.
6. Inter premolar, Inter molar Angle.
7. Anterior lower Facial height.
All these signs will not be found in an individual
These signs are not clearly developed before puberty
Schudy’s concept of Mandibular notion
The rotation of the mandible result from inharmony
between vertical growth and anteroposterior or horizontal
growth of the mandible.
He dealt with growth increments which cause positional
changes of the chin.
To those increments which cause the chin to move
vertically he applied the term -VERTICAL GROWTH
To the one increment (condyle) which causes the chin to
move forward he applied - HORIZONTAL GROWTH
He named the condyle as horizontal element and listed
out three vertical elements
1. growth at nasion & corpus of the maxilla.
2. growth of the maxillary posterior alveolar process
3. growth at the mandibular posterior alveolar process
causing the molar teeth to move occlusally.
If the condylar growth is greater than the vertical growth
in the molar area, the mandible rotates COUNTER
CLOCKWISE resulting in horizontal change of the chin and
less increase in facial height Extreme of this condition cause
CLOSED BITES . causes increase in facial angle and
flattening of MANDIBULAR PLANE.
Conversely if vertical growth in the molar region is
greater than that at the condyles, the mandible rotates
CLOCKWISE resulting in more Anterior facial height.
Extremes of this condition cause OPEN BITES : with
steepening of mandibular plane.
The horizontal condylar growth is pitted against the
combined vertical elements of growth . The final vector of
growth of the chin is a resultant of the struggle between
horizontal growth and vertical growth.
When the growth at the condyle equals the growth of the
vertical elements, the net result is usually downward and
In clockwise rotation the point of rotation being the
In counter clockwise rotation the point of rotation is the
most distal mandibular molar in occlusal contact.
He called the ratio between horizontal and vertical growth
increments as POSTERIOR GROWTH ANALYSIS. It is
this ratio depicting the relationship of vertical & horizontal
increments one to another that controls the forward
growth and rotation of the mandible.
ENLOW’S CONCEPT OF MANDIBULAR ROTATION:
1. Displacement type
2. Remodeling type
Rotational positioning of the entire mandible.
Caused by changes in the placement of the functional
contacts with both the cranial floor and the maxilla.
The dimensions & angular positions of the cranial floor
and maxilla directly affect the consequent rotational
position of the mandible.
If cranial base angle is open downward and backward
DISPLACEMENT rotation of the mandible and converse
occurs if the angle is closed.
If Nasomaxillary and dental complex is vertically long
downward and backward DISPLACEMENT rotation of
the mandible, and www.indiandentalacademy.com
converse occurs if nasomaxillary
complex is vertically short.
There are two reasons why a mandible undergoes the
remodeling type of rotation.
1. To produce a more upright ramous alignment relative to
This accommodates the continued vertical growth of
ethmomaxillary region and the eruption of permanent
2. To provide ramus-corpus angular adjustments to
accommodate the effect of the whole mandible
e.g., : of the displacement rotation causes more upward &
forward alignment of the mandible as a whole then the
remodeling rotation, partially or completely offsets this by
opening the ramus-corpus angle.
On contrast a downward and backward wholemandible displacement can be offset by closing the ramuscorpus angle by remodeling rotation.
It is necessarily a function of the ramus, rather than the
corpus to provide the basic remodeling changes leading to a
more open/more closed ramus-corpus angle.
The same combinations of resorption and deposition in
the various parts of the ramus that bring about relocation of
the ramus in posterior direction also serve to remodel and
adjust the RAMUS CORPUS ANGLE.
As growith proceeds, the utilization of these ramus
growth changes to alter ramus corpus alignment decreases
and finally ceases.
Another remodelling mechanism takes over.
• Condyle previously growing in a more vertical
direction now begins to grow anteriorly as well.
• This anterior condylar growth is complemented by
bone deposition superiorly on the anterior border of the
• Resorption continues inferiorly on the anterior border
to provide space for molars.
• A converse combination of remodelling takes place on
the posterior border.
BJORK AND SKIELLER subsequently focused attention
on different patterns that emerged when different
registrations for superimposition were used.
These various patterns can be expressed in a rotational
The rotation of mandibular corpus
I. Total rotation:
(implant line) relative to the anterior cranial base.
Solow an Houston
II. Matrix rotation: Rotation of soft-tissue matrix of the
mandible (Tangential mandibular line) relative to the
Center - condyles
II. Solow an Houston
III. Intramatrix rotation: The difference between the total
rotation and the matrix rotation. The change in inclination
of an implant or reference line in the corpus relative to the
tangential mandibular line.
It is an expression of the remodeling at the lower border
of the mandible.
center – corpus.
III. Solow an Houston
MATRIX AND INTRAMATRIX ROTATIONS
PROFFIT : Total Rotation
= Internal rotation
: Matrix Rotation
SOLOW : Apparent Rotation
For an average individual with normal vertical facial
proportions there is about -15 of Internal Rotation (Total, True)
from 4 years – Adults life and 11-12° of external rotation.
(- sign = forward rotation).
X= 150 -(11-12)0
X= 30 - 40
15° – External, Intramatrix,
3° – 4° - Total, Matrix,
The different interpretations of the intra matrix rotation were
given by :
1.Lavergne and Gasson - He defined rotations as
a.Morphogenetic - Concerning the shape of the mandible
similar to intramatrix rotation.
b. Positional – Dealing with the position of the mandible.
They used a line joining condylon and pogonion to
super impose cephalogram and determine the angle between
the 2 implant lines.
They concluded that Anterior rotation of the mandible
is associated with a vertical or even anterior condylar growth
direction and a marked closure of the gonial angle and these
minimize the effects of condylar growth.
They postulated that intramatrix rotation is essentially
a compensating mechanism which is capable of reducing or
enlarging the mandibular length by opening or closing the
2. Dibbets - He gave a third interpretation which is based on
two hypothetical divergent patterns of growth.
a. A circular growth pattern resulting in only intra matrix
rotation and no enlargement of the mandible.
A linear growth pattern characterized by absence of
intramatrix rotation but with mandibular enlargement.
He showed that the external configuration of the
mandible need not change its form or position within the
head to allow intramatrix rotation and any resorption or
deposition only serves to maintain the original contours.
He also stated that every millimeter of condylar
growth along the pogonion condylon diagonal would enlarge
the mandible by 1mm.
This is compensated by remodelling at the lower
border. This mechanism is termed as the counterbalancing
rotation. Thus counterbalancing rotation is a mechanism that
(i) Neutralizes effect of www.indiandentalacademy.comcondylar cartilage.
growth of the
Rotation of Maxilla :
Core of the maxilla
above the alveolar process.
alveolar process, bones
surrounding air passages.
Internal rotation: The cove of the maxilla undergoes a
small and variable degree of rotation forward or backward.
At the same time resorption of bone on the nasal side and
apposition of bone on the palatal side in the anterior and
posterior part of palate occurs.
Eruption of molars and incisors occurs.
The above two factors account for the external rotation.
For most patients the external rotation is opposite in
direction and equal in magnitude to Internal rotation.
The two rotations thus cancel each other and the net change
in jaw orientation (palatal plane) is zero.
Variation from this average pattern is common and result in
moderate variation in Jaw orientation.
ROTATION OF MAXILLA
PREDICTION OF MANDIBULAR GROWTH ROTATION
If an attempt is made to assess the growth trend at an
early stage, this information can be used in designing the
treatment of evaluating the problems that may arise before
growth is complete.
In spite of several attempts in recent years, there is still
doubt as to the extent to which growth of the face as a whole
can be predicted from a single profile radiograph.
In an attempt to analyse the possibility of predicting
growth of single facial dimension, Bjork and palling correlated
linear and angular measurements at pubertal age with residual
growth of these dimensions up to adulthood.
correlations were however found to be low.
Hixon suggested that the best estimate of an adult facial
dimension for a given child is to use the dimension presented
by the child and add to that the remaining average growth for
the group. This method was adopted by several authors.
However, this estimate would fit an average but not an
extreme growth pattern, where prediction from a clinical point
is more important.
Lavergne tried to individualize the prediction by a
subdivision according to the morphogenetic types.
Ricketts arcial method of long range growth prediction
uses geometric procedures to gain information about the
growth pattern of the mandible.
A computerized system for short range facial growth
prediction and treatment simulation, based on longitudinal
observations of individual growth rate and direction has been
developed by Bjork-Jorgensen.
A growth analysis consists of essentially 3 items
assessment of the development in shape of the face.
2. assessment of whether the intensity of the facial growth is
high or low.
evaluation of the individual rate of maturation.
In the assessment of shape there are three methods.
I. Longitudinal method – Consists of following the course of
development in annual cephalometric films.
It is for the subjects displaying the most pronounced
changes in facial forms that the diagnosis of growth pattern
1. Pattern of growth is not constant and may be changed later.
2. Permits observation of changes in the saggital jaw relation
with growth and those occurring in the vertical jaw relation
Changes in the vertical positions of the jaw in the form
of rotation appear to be smaller when assessed with
conventional longitudinal X-ray films by using the base of
the mandible as the reference than when assessed with the
help of implants.
Analysis of vertical development of the face may done
using natural reference structures in the mandible by
superimposing two radiographs taken at different ages and
orienting reference to these structures, one may estimate
the growth pattern of the mandible by reading the angle
between the Nasion sells lines for the two ages.
II. METRIC METHOD
Aims at a prediction of facial development on the basis
of facial morphology, determined metrically from a single Xray film. However, prediction of development from size and
shape at childhood is not very accurate. The growth in length
of the mandible during adolescence could not be judged from
its size before puberty and also the changes in shape of the
face during adolescence, expressed in terms of angular
measurements also weekly correlated with the shape of the
face at 12 years which is the age at which treatment is
II. STRUCTURAL METHOD
Is based on information concerning the remodelling
process of the mandible during growth, gained from the
The principle is to recognize specific
structural features that develop as a result of remodelling in a
particular type of mandibular rotation. A prediction of the
subsequent course is then made on the assumption that the
trend will continue.
Gonial Angle and mandibular rotation
The size of Gonion angle influence the number of degree
of counter clockwise rotation of mandible.
The smaller the gonion angle, the greater the rotation is
produced for each mm of forward movement of pogonion
Facial divergence and mandibular rotation
The degree of facial divergence (SN – MP) has a
significant bearing on mandibular rotation.
Larger SN-MP angle, the more the mandible tends to
become steeper and the chin moves more backward.
The smaller the angle, the greater the tendency of the
mandible to become www.indiandentalacademy.com to grow forward.
flat and the chin
REVIEW OF LITERATURE
1. Schudy study :
Growth was studied on 62 patients.
29 – 11 – 14 years
33 – 8 – 11 years
50 – 11 – 14 years
Aim of the study – To determine the cause of mandibular
Measuring vertical growth in the first molar teeth and
relating this growth to that at the mandibular condyles.
Results : Untreated
Effective condyle growth
73% of vertical growth in the Untreated group
(4.6mm) was in the maxilla and 27% in the mandible.
Treated 68% maxilla, 32% mandible.
Thus he concluded that MAXILLA is responsible for
about 70% of total vertical growth and has an important
effect on the ‘tilt’ of the mandible.
2. Alf Tor Karlsen -1997 Angle orthodontist.
Aim : - Association between vertical craniofacial growth and
mandibular growth rotation.
Study group –
(i) Low MP-SN angle
(ii) High MP-SN angle
- Longitudinal study from 6 – 15 years of age
Results : • Increased posterior
Positively correlated with
lower facial height
FORWARD MATRIX ROTATION
Increase in ramus height
Irrespective of MPA / age
2. Increase in LAFH
Weakly correlated with
mandibular rotation. (?)
Strongly and positively
correlated with increased in
Over development of LAFH in high angle cases
occurred because the steep mandibular plane directed corpus
growth more downward.
3. 1995 A.O
The same author did a longitudinal study with boys
having low and high MP-SN angles.
Aim :- Compare the two groups with regard to dimensional
changes and mandibular growth rotation.
Result : - Significant correlations were almost exclusively
noted between dimensional change and total rotation and
dimensional change and matrix rotation.
4. 1984 – Nov- Bjork and Skieller A.J.O.
Aim – To estimate the possibility of predicting the direction
and amount of growth rotation of the mandible on the basis
of morphologic criteria observed on a single profile
radiograph at pubertal age.
Forty four morphologic variables were employed and
four among them gave the best prognostic estimate (86%) of
mandibular growth rotation in the sample.
a. Proportion between posterior and AFH (Index – I)
b. Lower Gonial angle (GOL)
c. Lower border inclination (NSL – ML1)
2. Inter molar angle (MOLs – MOLi)
3. Shape of lower border (ML1 – ML2)
4. Inclination of symphysis (CTL – NSL).
5. AJO Dec – 1998
In response to Bjork & Skieller’s article (1984 AJO)
Laurel R. Leslie Published a article assessing the reliability of
their method of predicting growth rotation using the four
They concluded that only 9% of the variability in
mandibular growth rotation could be accounted for using the
four variables in combination in contrast to 83% given by
Thus he stated that the method does not permit clinically
useful predictions of future mandibular growth rotation.
1. Downward alignment
of the whole mandible at the
condylar pivot has a mandibular retrusive effect.
Only Corpus mandibular protrusive effect.
Upward alignment of the whole mandible
Mandibular protrusive effect
Only corpus Mandibular retrusive.
2. The more extreme the rotation of the mandible during
growth, the greater the clinical problems that is presents.
Extreme rotation greatly influence the path of eruption of
the teeth, magnitude of tooth eruption, anteroposterior
position of incisor teeth.
Path of eruption of max teeth
Downward and somewhat forward
In normal growth, maxilla usually rotates a few degrees
It may be normal but usually the maxilla rotates slightly
Forward Rotation of maxilla Tends to tip the incisors
forward and increase
Backward Rotation of maxilla Directs the anterior teeth
relatively up righting
them and decreasing
During adolescence about half the total maxillary teeth
movement is due to rotation of maxilla (Teeth moved along
with the jaw - Translocation).
Path of eruption of mandibular
Upward and forward
Lingual positioning of
relative to mandible.
Forward rotation of growth
Lingual positioning of mandibular incisors
Molars migrate further mesially during growth than the
Decrease in the arch length
The forward rotation progressively uprights the
incisors, causing a tendency toward crowding.
Incase of pronounced forward rotation, there is a major
risk of deep bite developing.
In the case of backward rotation, opening of the bite is
difficult to prevent during treatment so in the case of
extreme forward rotation a stabilizing appliance like bite
plane is introduced before puberty and continued until
According to Bjork, it is advisable to delay orthodontic
extractions until beginning of pubertal growth spurt.
2. Facial patterns :
SHORT FACE PATTERN
Excessive forward rotation of mandible during growth.
Short Anterior LFH
Horizontal palatal Deep bite and
Excessive forward rotation may be due to
Increase in internal mandibular rotation
(ii) Decrease in external rotation
LONG FACE PATTERN (INCREASED LAFH)
Backward rotation of mandible
Anterior open Increase
Mandibular backward rotation result primarily from
Lack of normal internal rotation
Or even backward internal rotation
The internal rotation is primarily matrix rotation (Corcondyle) and not intramatrix rotation.
Backward rotation of mandible also occur in patients
with abnormalities or pathologic changes in TMJ
3. According to schudy : Clockwise rotation of mandible (effect
Would not help reduce ANB angle
Not aid in correction of class – II molar relation.
Would tend to help connect the vertical overbite of
incisors and maintain it.
Counter clockwise rotation
Tends to increase the vertical overbite (deep bite) and
renders vertical overbite correction and retention more
According to schudy the condylar growth versus vertical
growth determines the mandibular rotation.
Orthodontic treatment does not stimulate growth at the
condyles. It is only the vertical increments that we may
possibly alter with orthodontic treatment.
Inhibition of growth of vertical increments will have
the same effect as stimulating growth at the condyle.
So if vertical growth is deficient we try to stimulate it.
(Cervical pull head gear, class II elastics). If vertical
growth is excessive we try to inhibit it (Inhibit downward
growth of maxillary molar – high pull head gear).
4. It is also important to identify the relationship between jaw
base rotations and occlusal findings (e.g., Inclination of
upper anteriors and lower anteriors and over bite) and
accordingly plan the treatment, especially if the patient is
in growth phase.
6. Combinations of maxillary and mandibular rotation and
its clinical implications (Lavergne and Gasson 1982). The
combinations are very important for occlusal relationship.
Convergent rotation of jaws during growth.
A deep bite which is very difficult to correct even by
Divergent rotation skeletal open bite often results.
Severe cases require orthognathic surgery.
Rotation in the same direction :
The occlusal relationship is maintained normally in
most situations (e.g., deep bite avoided in cranially
directed rotation of both jaws).
COMBINATIONS OF ROTATIONS OF JAW BASES
7. Upward and forward tipping of anterior maxilla is often
observed in confirmed mouth breathers.
8. Mandibular rotation is caused by both growth dependent
and functional influences only functional influences can
be altered therapeutically while growth can only be
guided so the rotation of mandible can be only
moderately influenced therapeutically.
Generally the inclination of maxillary base is stable
and no growth dependent influences seen, thus the
inclination can be influenced by both fixed orthopedic and
functional therapeutic techniques.
Though different authors give different mechanisms
and terminologies for Growth rotations, the jaw should
rotate either forward or backward.
It is upto the
orthodontists to identify the rotation early and its clinical
presentation and apply it in treatment, so that treatment
can be started at the earliest.
1. Contemporary Orthodontics
2. Handbook of Facial Growth
3. Orthodontic Diagnosis
4. Dento facial orthopeadics with functional appliances Petrovic
5. Prediction of Mandibular growth rotation - Bjork (1969 June
6. The rotation of the mandible resulting from growth : Its
implications in Orthodontic treatment - F.F. Schudy (1965
7. The puzzle of growth rotation June 1995)
J.M.H. Dibbets (AJO
8. Mandibular rotation and enlargement – J.M.H. Dibbets (AJO
9. Bjork (1972) AJO
Leader in continuing dental education