Growth prediction3/certified fixed orthodontic courses by Indian dental academy

GROWTH PREDICTION
• Introduction
• Definition
• Uses
• Methods
• Limitation
INDIAN DENTAL ACADEMY
Leader in continuing dental education
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GROWTH PREDICTION
• Introduction
• Scammon‟s curve
• Cephalocaudal gradient
• Data from various studies
Bolton brush study
Iowa growth study

GROWTH PREDICTION
Definition
• Assumption of ability to estimate
practically future growth.
• Asserting on the basis of theory, data or
experience but in advance of proof.

GROWTH PREDICTION
Why it is necessary ?
• Helps in diagnosis
• Development of satisfactory treatment
plan

Growth prediction
Methods of predicting facial growth change
 According Bjork
 Computerized prediction methods
 Logarithmic spiral
 Arcial growth of the mandible
 Visual treatment objective
• Jacobson and Sadowsky
• Ricketts
• Holdways

GROWTH PREDICTION
According Bjork
• Longitudinal approach
• Metric approach
• Structural approach

Growth prediction
• Longitudinal approach
- Tweed on growing pt.
- 2 lateral ceph. 12-18 months apart
- 3 categories Type A
Type B
Type C

Growth prediction
type A – middle & lower face growth in
unison + equal change in vertical &
horizontal dime.
Type B – middle face > lower face
Type C – lower face < middle face

Growth prediction
Tweed – growth pattern remain constant.
- Moore et al
- No use in predicting changes.
• Limitation
Accurate in Retrospective.
• Conclusion –
Not accurate method.

Growth prediction
• Metric approach
- consist of measuring different structure on a single
radiograph & then relating these measurement to
future growth changes .
Correlation coefficient =r
- Association b/w 2 variable
- Direction either positive or negative of the
relationship
- It is used in prediction by -
Squaring the value of „r‟ = coefficient of determination
( amount of variation of 2nd variable )

Growth prediction
• Bjork ,Harvold ,Lande, Solow ,others
- Correlation Coefficient not more 0.4 or 0.5
- 16% to 25% variation
Conclusion
this methods is least clinically siginificant

Growth prediction
• Structural approach
- To predict mandible
growth direction
- Superimposition on
metallic implant
- 7 areas
1. Inclination of condyle
2. Curvature of the
mandibular canal
3. Inclination of symphysis

Growth prediction
4. Shape lower border of
the mandible
5. The interincisal angle
6. The interpremolar or
molar angle
7. The anterior lower facial
height
Conclusion
This is also least clinically
siginificant

Growth prediction
• Skeiller ,Bjork, and Linde – Hansen
(Tried to quantify it)
• 4 variable
1. MP inclination - Anterior cranial base (MP:SN)
or Ratio of posterior & anterior facial height
2. The intermolar angle
3. Shape of lower border of the mandible
(GO - ME to lower border of the mandible)
4. Symphysis inclination (sym. Anterior surface –SN)

Growth prediction
• Measurement of these variables were
included
R squar = 0.8612 = 86% variation in direction of
mandibular growth
• But 86% was high value

Growth prediction
 According Bjork
 Computerized prediction methods
 Logarithmic spiral
 Arcial growth of the mandible
 Visual treatment object

Growth prediction
• Computerized prediction methods
• Tool of analysis not a method
• Advantage
1. Facilitates testing
2. Complex formulas to growth prediction

Growth prediction
• Ricketts 1970 – potential of computerization
- Cephalogram (diagnosis ,T/P)
• Greenberg & Johnston
- Computer forecasts not better than the
assumption of average growth
- No difference bet. this & method based on
simple addition of the average changes.

Growth prediction
According Bjork
Computerized prediction methods
Logarithmic spiral
Arcial growth of the mandible
Visual treatment object

Growth prediction
• Logarithmic spiral
Golden triangles
Why
 how the position of 3 foramina on the
unitary , logarithmic spiral in anterior open
bite and deep bite pt. (Melvin. Moss )

Logarithmic spiral

Evolution of logarithmic spiral
• Sectioning of a line
• Smaller section is proportional to large section
• Larger portion is called „golden section‟
• Larger section is Phi /

• Small section is 1
• Larger = 1.618 times
the smaller
• The smaller is 0.618
the length of the
larger

• Phi relationship
- Plants, animals, human body , face
• Golden progression – series of these
proportions
- Symbols -
2
,
3
,
4

• Golden triangle
• Base of a triangle 1.0
• Sides of equilateral
triangle 1.618
• Forms a 72 – 72 -36
degree

• Bisection of one base
angle cross the opposite
side
• Divide that side into a
golden section
• Form new golden
triangle

• Bisection of golden triangle can be made in a series

• Curve used to connect
the points on a series of
the triangles
• Form Logarithmic spiral.

Logarithmic spiral
• So human mandible
grows as a logarithmic
spiral on the arc.

Logarithmic spiral
Melvin Moss
• Aim - determine the position of 3 foramina on the
unitary , logarithmic spiral in anterior open bite and
deep bite pt.
• These conditions can be anticipated at young age
even before orthodontic diagnosis
• Foramen
1. Foramen ovale
2. Mandibular foramen inferior alveolar nerve
3. Mental foramen

Logarithmic spiral
• Introduction
Studied the position of the inferior
alveolar nerve
• Conclusion
These foramina , at all ages fit precisely
upon a single mathematically defined
logarithmic spiral

Logarithmic spiral
Foramen “moved” down
along this same
logarithmic spiral in
geometric fashion
The gradient of motion
directly increasing with the
distance of the foramina
from cranial base.

Logarithmic spiral
• Method and materials
2 group of pt.
Columbia university University of utah
16 pt - 3 m & 4 f 4 groups
(Ant Open bite) 10 pt Normal swallowers
- 4 m & 5 f 10 pt Tongue thrust
(Deep bite) 5 pt Angle II div 1
5 pt Ant open bite

Logarithmic spiral
• Tracing of cranial base & mandibular outline
from films
• Superimposed the logarithmic spiral
• Position of 3 foramen marked on it.

Logarithmic spiral
• Result
 Singular position of
foramen ovale in
anterior open bite.
 Foramen ovale located
farther down the
spiral.
Help in diagnosis
 No sexual dimorphism

Logarithmic spiral
 Mandibular & mental
foramen also further
down the logarithmic
spiral in AOB
 Not as diagnostically
unique
 Distance between
these not decreased.

Logarithmic spiral
 Foramen oval cluster
relatively „high‟ up on
the spiral in deep bite.

Logarithmic spiral
Discussion
Mandibular shape - inferior alveolar nerve
- 2 factors foramina position on the spiral
distance between them.
• Fetal & circumnatal periods
- All foramina placed near the origin of spiral and
nearer to each other
- Flatter curvature
- Mandible gonial angle relatively obtuse or flat.

Logarithmic spiral
With growth , all foramina moved down along
the spiral and distance
• Ramus becomes more erect relatively to
corpus
• Gonial angle becomes acute

Logarithmic spiral
• Anterior open bite
 Foramen ovale down
along the spiral
Distance mand. &mental
foramen not decrease
Course of inferior alveolar
nerve flatter
 Ramus & corpus more
obutse www.indiandentalacademy.com

Logarithmic spiral
• Deep bite
„Higher‟ up on the spiral
 3 neural foramina
distance not decreased
 Inferior alveolar nerve
curvilinear course
 Ramus & corpus more
acute

Logarithmic spiral
• Anterior cranial base – Richardson
Sella - NA
Deep bite
Anterior
open bite

Logarithmic spiral
Anterior open bite Deep bite
• Gonial angle
Ar –Go-Me Obtuse Acute
• Mandibular size
Ramus Shorter No significant
Corpus Normal length linear difference
• Anterior cranial base
(S-Na) No difference

Logarithmic spiral
Anterior open bite Deep bite
• Periosteal functional matrix
(Massater) No difference in attachment site
• Capsular functional matrix
Oral functioning space
Abnormal Normal

Growth prediction
According Bjork
Visual treatment objective

Principal of Arcial growth of the
mandible
Robert M. Ricketts
• Purpose – explain a method for finding the arcial
growth of the mandible and to enumerate some uses of
the principal
• Based on computer study
• Predict long range growth forecast

Arcial growth of the mandible
• Principal – mandible grows by superior-
anterior apposition at the ramus on a
curve or arc which is a segment formed
from a circle.
• Radius – Pm to point Eva.

• Growth of the mandible
1. Roentgenographic cephalometric
2. Bjork
3. Enlow
Bjork
- variation in the mandibular bending.
- Resorption of lower angular border
- 3rd molar crypt – stable longitudinal reference
Enlow
3D growth pattern Remodeling area
Reversal areas of stabilitywww.indiandentalacademy.com

Prediction of mandibular growth
• Primary methods
- Long axis of condyle & neck
- Lower border of mandible
• „Central core‟ cephalomertrically
• Search for „reference point‟
• External mandible (mandibular plane,ramus plane,
condyle – symphysis )

• Xi point – center of
ramus
Occlusal plane
Entrance of neurotrophic
bundles

• Bisect the height of ramus from the
sigmoid notch

• Dc point
• Condyle axis
• Corpus axis
• Change in angle - change
in mandibular form
• Second method –
Magnitude & angular
relation.
• More successful as a
method of forecasting

• Suprapogonion / Pm
Reference point
Ricketts – stress center
Enlow – site of reversal
line
Bjork - cosistent

• The objective of research was still towards
finding a method to critically predict future
form and size of the mandible over the
long range.

computer study
• 5 yrs growth study of mandible & lower
dental arch
• In lateral & frontal head films -362
measurement

Material
• 40 pt – lateral & frontal cephalometric film
• One group – 8 yrs another group -13 yrs
• No orth. t/t
• 20M & 20F
• 20 – class I with normal occlusion
• 20 - class II malocclusion

Findings
• Mandible bend ½
degree per year.
• Bending in an orderly
manner.
• Growth arc was
operative.

• First arc – Pm ,Xi ,Dc
• Straightening of the
mandible
• To determine the true arc of growth of the
mandible

• Second arc - tip of
coronoid , R1 , Pm
• Segment of circle small in
radius.
• Excessive bending of
mandible

• True arc – Condylar &
Coronoid process ,
Ramus center & it‟s ant.
Border
• Radius increase or
changing with the size of
the mandible
• Changing arc or ultimate
spiral would result.
• Growth could not be
represented as simple
segment of circle www.indiandentalacademy.com

Stress lines
• 850 yrs. Old mandible –
William B. Downs
• Disintegration of
interprismatic subs.
• Stress lines in the outer
& inner plates

• Examination of
stress lines / lateral
surface
Convergence at
protuberance menti
Upward ,backward &
outward from EO
Gnarled area at the
coronoid base.

• Stress line /medial side
Mylohyoid ridge
YM /Y-shaped bony
prominence
- Center of quadrant of
ramus
- Inner & outer cortical tables
showed confluence
TP/ Triangular plane –
Nutritive foramina

• 2 new point - Eva &TR
• Eva- forking of stress lines
in ramus
• TR /true radius – center
of circle from Pog through
Eva
• Mu point

• Mandible size increased,
increment added to the
arc at the sigmoid notch.
• Predicted mandible was
almost absolutely correct
in size and form when
compared with the final
composite

• Mandible growth occurs
on a arc
• This method proved
extremely accurate in
50 treated cases
which were predicted
and compared for
periods of as long as
14 yrs later.

• Amount of growth to
forecast on the arc
- 2.5 yearly increase
14.5 F & 19M
• Symphysis lower
border – 1mm each 8
yrs / M

• Coronoid & condylar
process – different
• Coronoid – 0.8mm/yr
• Condylar - variable
1. Short & weak – 0.0mm
2. Long condyles –
0.4mm/yr
3. Average – 0.2mm /yr

• Gonion angle growth
50% of the total
increase in mandibular
growth
• Females - no further
addition
• Males – above +0.2mm

• External oblique ridge
0.4mm/yr.
• RR point – stable bone
Ramal width

• Impaction of third molar and Arcial
growth prognosis –25 adult skull
normal occlusion
1. Lower third molar 50 % ahead the EOR
50% favorable prognosis
2. Mesial to the EOR – 100 % favorable prognosis
3. Distal to the EOR – poorer
45 % of the nonextracted cases required third molar
extraction.

• Bisect the height of ramus from the
sigmoid notch down to the lower border in
a perpendicular plane from FH ,then
bisected the width of the mandible called
XI point

• 2 new point - Eva &TR
• Eva- forking of stress lines in
ramus
• A center of upward & forward
quadrant of ramus
• By bisecting R2 & R3 point
• TR /true radius – center of
circle from Pog through Eva
• Mu point

• Class III
The amount of mandibular
growth in the forecast is
one sixth more in the
classIII

• May be occur in
closed bite faces

Growth prediction
According Bjork
Visualized treatment objective

Visualized treatment objective
• Definition
• Uses
• Ricketts
• Holdways

• Definition
It is a visual plan to forecast the normal
growth of the pt and the anticipated
influences of treatment , to establish the
individual objectives we want to achieve for
that pt

• Uses
1. Predict growth over an estimated T/t time
2. Analyzes the soft tissue facial profile
3. Determines favourable incisor repositioning
based on an „ideal‟ projected soft tissue
profile
4. Determines total arch length discrepancy

5. Aids in determining b/w extraction &
nonextraction treatment
6. Surgical orthodontic correction

• Ricketts
• Holdways

ALEX JACOBSON &
P.LIONEL SADOWSKY
• All cephalometric headfilms to be taken in the lips
closed position even if they are strained to close
• Construct a VTO by considering average growth for
an estimated 2 yr period of active t/t & the objective
we want to achieve with our mechanics

Cephalometric tracing for VTO
• Anterior & posterior cranial base
• Pterygomaxillary fissure
• Orbit
• Anterior outlines of frontal bone
• Nasal bone & Nasion
• ANS &PNS ,hard palate
• Upper central incisor & it‟s alveolar process
• Mandible
• External auditory meatus
• Soft tissue profiles
• Upper & lower molarwww.indiandentalacademy.com

Cephalometric tracing for VTO
• BAN (Basion-nasion line)
• Line Na - POINT A
• F H PLANE
• Occlusal plane
• Downs mandibular plane
• Facial axis
• Holdway‟s line
• Facial plane

Visual treatment objective
Step of VTO
• Step 1 obj. – To draw frontonasal area , BAN & NA
line.
• Step 2 obj. – Growth in frontonasal area over 2 yr.
- Frontonasal area 1.5 mm growth
- 1/4mm per year ( Dr. Holdway‟s studies )

• Step 3 object – Mandible growth in vertical direc.
- Ant. Portion of mandible
- Soft tissue chin
- Down‟s mandibular plane
• Superimpose on the facial axis
• The distance b/w VTO & ceph Ban line should be 3
times the amount of growth expressed previously in
FN area

Step 4 obj. – Mandible growth in horizontal
direction.
- Draw the Post border of mandible
• Forward growth at chin point = Nasion
• Total vertical facial height as well as forward
location of chin established

Step 5 obj. – To locate maxilla & lower half of nose
• Superimpose on NA line & move up
• There is 40% of total vertical growth above BaN
line & 60% below mandible
• Nose growth 1mm/year.
Step 6 obj. – To locate and draw the occlusal plane
• Superimpose on NA plane
• Vertical growth is 50% above maxilla & 50% below
mandible www.indiandentalacademy.com

Step 7 obj. – To determine soft tissue lip contour
using the new H-line
• The distance b/w upper lip contour & H-line is
3 - 7mm (Dr. Holdway‟s studies )

Step 8 obj. – To relocate the maxillary central incisor
• Upper lip thickness = Basic upper lip thickness
( within 1 mm )
• Lip strain is difference b/w above measurement
• Maxillary incisor rebound - 0.5mm in class I
- 1.5 mm in class II
In this case
Lip strain = 4 mm
Lip movement = 4 mm
Maxillary incisor rebound = 1.5 mm
Total 9.5 mm

Step 9 obj. – To reposition lower incisor
- Calculate resultant arch length change
• Arch length change - measure the distance b/w
old and new incisor position (2mm)
• Double the above distance
• Arch length change is in this case is 4 mm

Step 10 obj. –To reposition mandibular first molar
• Total arch length discrepancy = arch length loss
+arch length discrepancy / model discrepancy
8 mm = 4 mm + 4mm
• Extraction of 2nd PM on both side - 15 mm space
Step 11 obj. – To reposition the maxillary first

• Holdways
• Ricketts

A Soft - tissue cephalometric analysis
Reed A. Holdway
• Based on soft - tissue measurement
Variations
• Sella nasion line is used express forward growth
at nasion
• Growth on facial axis is 3mm/yr except during
growth spurts

• Head films should be taken with the pt‟s
lip touching position

Original tracing – 9 reference line
• SN plane
• FH plane
• Occlusal plane
• Nasion to Pog line (hard & soft tissue)
• H- line
• Nasion to point A line / facial plane
• Facial axis
• Down‟s Mandibular plane

Steps of VTO tracing
Step 1 – Draw Frontonasal area
Sella – nasion line
Nasion- point A line

Step 2 - Express horizontal growth in the FN
area for the estimated T/t
• Growth at nasion is 0.66 to 0.75 mm/yr
• Prediction of growth at nasion is an overall
prediction for all midfacial structure

Step 3 – Mandible growth in vertical dire.
• Growth on facial axis is 3 mm/yr except in growth
spurt period
Step 4 – Mandible growth in horizontal dire.
• At this point total vertical height has been forecast

Step 5 – To locate maxilla, the new point A &
lower half of nose
• Vertical growth above the SN line & below the
mandible is in ratio of 40 :60
• The vertical growth of the nose over 2 yr period
keeps pace with the growth from the maxilla
vertically to the anterior cranial base

Step 6 - locate and draw the occlusal
plane
• Vertical growth is 50% above maxilla & 50%
below mandible
• The occlusal plane is located 3 mm below the lip
embrasure

Step 7 – To determine soft tissue lip contour
using the new H-line
• The distance b/w upper lip contour & H-line is
3 - 7mm
• Short & thin lip – 3 mm
• Long & thick lip – 5 mm

Step 8 – To relocate the maxillary central
incisor
• Upper lip thickness = Basic upper lip thickness
( within 1 mm )
• Lip strain is difference b/w above measurement
• Maxillary incisor rebound - 0.5mm in class I
- 1.5 mm in class II

Step 9 – To reposition lower incisor
- Calculate resultant arch length change
• Arch length change - distance b/w old and new
incisor position
• Double the above distance
• Arch length change is in this case is 8 mm

Step 10 – To reposition mandibular first molar
• Total arch length discrepancy = arch length change
+arch length discrepancy / model discrepancy
10 mm = 8mm + 2mm
• Extraction of 2nd PM on both side - 15 mm space
Step 11 – To reposition the maxillary first

RICKETTS
Original tracing
• Nasion
• ANS
• Point A
• PM
• POG
• CC
• Basion
• DC
• XI

Construction of VTO
• Cranial base prediction
• Mandibular growth prediction
• Maxillary growth prediction
• Occlusal plane prediction
• The location of the dentition
• The soft tissue of the face

VTO – Cranial base prediction
• Mark at CC point
• Trace BaN Plane
• Nasion -1mm /yr
• Basion – 1 mm/yr

VTO –Mandibular growth prediction
• Condylar axis growth
• Corpus axis growth
• Symphysis growth

VTO – Mandibular growth prediction – Rotation
• Mandible rotates open or closed from the effects of
mechanics used & the facial pattern present
• Mechanics
5 mm convexity reduction Facial axis open 1 degree
4 mm overbite correction
• Facial pattern

VTO – Mandibular growth prediction – Rotation
• Superimpose at Basion
• Rotate VTO tracing up to open the bite at nasion or
down to open the bite
• This rotation depends on treatment effect
• Trace condylar axis, coronoid & condylar process

VTO – Mandibular growth prediction
Condylar axis , Corpus axis growth
• Condylar axis moves 1mm /yr down from DC point
• PM moves forward 2mm /yr in normal growth
VTO – Mandibular growth prediction -Symphysis
growth
• Coincide old & new PM
• Copy the symphysis , mandibular plane
• Construct facial plane & facial axiswww.indiandentalacademy.com

VTO – Maxillary growth prediction
• Superimpose at nasion along the facial plane
• Divide the original & new menton into 3 part by
using 2 mark
• Superimpose mark 1 on original menton , copy the
maxilla

VTO – Maxillary growth prediction
Point A change related to BA – NA
• Position of Point A change with growth & different mechanics
Mechanics Maximum range
1. HG - 8 mm
2.Class II elastics - 3 mm
3.Torque - 1 to 2 mm
4.Class III elastics + 2-3mm
5.Facial mask + 2- 4mm
• Point A and APO plane

VTO – Occlusal plane prediction
• Superimpose mark 2 on original menton along facial
plane
• Copy the occlusal plane
VTO - Dentition - Lower central incisor
• Superimpose on the corpus axis at PM
• Place a point 1mm above to occ. Plane &
1mm ahead to APO line

VTO - Dentition - Lower first molar
• Arch length change is 4mm
• Leeway space is 4mm
VTO - Dentition - Upper first molar
Upper central incisor
VTO – Soft tissue area

Growth prediction
• Overall changes in size and relationship of
human face from childhood to adulthood
are difficult to accurately predict due to
influence of the combined and complex
effects of genetic and environment factor.

Growth prediction
• Facial and dental changes in Adolescent and their clinical
implication
Samir –E Bishara ,AO 2000,Vol.60,No.6
• Difference between functional matrices in anterior open
bite and in deep bite
Melvin L. Moss, AJO 1970, Vol. 42,No.3
• A principal of Arcial growth of the mandible
Robert M . Ricketts AJO 1972,Vol .42 ,No.4
• Provocations & perception in craniofacial orthopedics
Robert M . Ricketts
• Issues related to the prediction of craniofacial growth
James Todd , AJO 1981,Vol .79 ,No. 2
• A soft tissue cephalometric analysis and it‟s use in
orthodontic treatment planning
Holdway , AJO 1984 ,Vol. 84 ,No. 4www.indiandentalacademy.com

Growth prediction
• A Visulized treatment objective
Alen Jacobson , P Lionel Sadowsky
• Prediction of the mandibular growth rotation
Bjork , AJO 1969 , Vol. 39
• Bioprogessive Therapy – VTO
Ruel W Bench , James J. Higler , JCO 1977, November
• Contemporary orthodontics - William R. Proffit
• Orthodontic current principles & techniques
T.M Graber , Robert Vanarsdall
• Orthodontic principles & practice
T.M Graber
• Ricketts interview ,JCO 1975 ,may, jun ,july

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Growth prediction3/certified fixed orthodontic courses by Indian dental academy

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Growth prediction3/certified fixed orthodontic courses by Indian dental academy