Growth studies 2

GROWTH STUDIES AND
METHODS OF STUDYING
GROWTH.
www.indiandentalacademy.com

• Types of growth data
• Methods of gathering growth data
• Longitudinal growth studies
• Methods of studying bone growth

Types of growth data.
 Opinion
 Observations.
 Ratings and rankings.
 Quantitative measurements.
direct data.
indirect data.
derived data.

• Opinion
It is a clever guess based on experience.
they are the crudest form of scientific
knowledge.
• Observations:
They are useful for studying all or none
phenomenon.they are used in a limited way
when more quantitative data is available.

• Ratings and rankings:
certain data is difficult to quantify and thus
may be compared to conventional rating
scale .ratings make use of comparisons with
such scales.rankings array data in ordered
sequence according to value.

• Quantitative measurements:
Includes expressing an idea or fact as a
meaningful quantity or numbers.
• Direct data: derived from measurements taken
on living persons or cadaver with a measuring
device.
• Indirect data:derived from measurements taken
from images or reproductions of the actual
person.
• Derived data:obtained by comparing at least
two other measurements.www.indiandentalacademy.com

Methods of gathering growth
data.
• Longitudinal studies .
• Cross sectional studies.
• Overlapping or semi longitudinal studies.

Longitudinal studies.
• These are measurements made of the same
person or group at regular intervals through
time.
• Advantages:temporary temporal problems are
smoothed with time,
Variability in development within a group is put
in proper perspective,serial comparison makes
study of specific developmental pattern of
individual possible.
• Disadvantages:time consuming, expensive,
sample loss or attrition,averaging.

Cross sectional studies.
• These are measurements made of different
samples or different individuals and studied at
different periods.
• Advantages: quicker,less expensive,statistical
treatment of data is easier.studies can be
readily repeated.method can be used in
archeological data.
• Disadvantages:it must be assumed that groups
being measured and compared are
similar.cross sectional group averages tend to
obscure individual variations.

Semi longitudinal studies.
• Longitudinal and cross sectional studies can
be combined to to seek the advantages of
both.in this way one might compress 15
years of study into 3 years of gathering
growth data.

LONGITUDINAL GROWTH
STUDIES.

Bolton Brush growth study.
• The brush enquiry was initiated in 1926 by Prof T
Wingate Todd with a aim of studying skeletal
development .
• The Bolton study was initiated concurrently by Dr
Holly Broadbent Sr in 1929,which focused on
normal development of facial skeleton and
dentition.
• Sample size:5000 normal healthy children.
• Records:series of x-rays,casts,dental and medical
examination and psychological tests.

Bolton Brush growth study.
• The two collections merged officially in 1970.
• In 1975 the Bolton standards of dentofacial
developmental growth were published by Dr
Holly Broadbent jr.
• These standards are a series of averages that
represent optimum facial and developmental
growth and form a baseline for understanding and
assessing craniofacial growth.

Burlington growth study
• The aim of the study was to learn more about
malocclusion,evaluate preventive and interceptive
orthodontic treatment, and obtain a set of growth
records as a database for future studies.
• Sample size:1632 subjects followed
longitudinally.
• Records :series of x-rays, casts,photographs,height
and weight records and medical examination.
• The original concept for the study was presented
by Robert Moyers& the records were gathered
under Frank Popovich.

Burlington growth study
• More than 247 investigations &322 studies are
based on this growth study
• Longitudinal studies by Thompson & Popovich to
derive cephalometric norms of a representative
sample was based on 210 children followed for 15
years at the Burlington growth center.
• age sex and growth type specific craniofacial
templates were derived and static and dynamic
analysis were proposed on the basis of this study.

The Michigan growth study
• Sample size: 99 males & 92 female subjects
with an age range from 5-18 years .
• Sample was of European origin.
• Records:series of x-rays,study casts, height
& weight records ,and medical records.
• The earliest records were gathered by
Byron O Hughes who was succeeded by
Robert Moyers

The Michigan growth study
• Longitudinal studies done by Riolo et al
was based on a sample from the Michigan
growth center.
• Study done by Barry Grayson et al using
existing cephalostat based data to derive
analysis of 3-D form was based on the
Michigan growth study data base.

The Denver child growth study.
• Sample size :as many as 100 subjects of each sex
at each age.the length of individual record sets
varied from 2 to 20 years.the subjects were of
European origin.
• Records: lateral and PA view and plaster casts of
dentition.
• No summary of record sets exists and records do
not appear available for general use.
• based on a sample from this study Ram Nanda et al
evaluated age changes in the morphology and
position of the nose.www.indiandentalacademy.com

The Iowa child welfare study.
• Sample size:it is a diminishing longitudinal
study which began with 20 males and 15
female 4 year old subjects. Followed till 17
years of age. Non -orthodontically treated
patients of entirely European origin were
used.
• Records:lateral and PA views and dental
casts.
• The study as done under Samir Bishara.

The Iowa child welfare study
• Based on this study the changes in facial
dimensions & relationships as well as in
standing height were evaluated.
• The dentofacial relationships of 3 normal
facial types (long, average, short) from 5-
25 yrs of age was described & compared.

The Forsyth twin study.
• Sample size:consisted of records for 3
samples of twins for whom complete records
are available from 6-10 years,10-16
years,and 6-16 years.
• Records;series of x-rays,casts,height and
weight records.
• The study was done under the direction of
C.F.A Moorrees.
AIM:the study observed the dental ,somatic and facial
development of 414 pairs of twins.

The Meharry growth study
• Sample size:diminishing longitudinal records
of 160 American black subjects followed from
6-14 years.
• Records:series of x-ray films,casts, photos,
medical records taken every 6 months till
age14 and annually thereafter.
AIM:was to study the craniofacial growth
and form in the African Americans using
serial radiographic cephalometrics.

The Montreal growth study.
• Sample size:6-15years with at least 50 subjects for each
sex at each age and
• 10-19 years with at least 30 males and 20 females at
each age.(all of European origin)
• Records:lateral,PA view,OPG, hand wrist films,casts
and height and weight records.
AIM:To make available a reference data necessary to
perform growth assessments/predictions

The Krogman Philadelphia
growth study
• Sample size:consisted of mixed sub sample of 600
healthy white children, a serial sample of 150
black children followed from 12-18 years,410 sets
of twins;orthodontically treated patients and some
records of cleft palate subjects.
• Records:lateral, PA view and hand wrist x-rays.
• The records were originally gathered by Wilton M
Krogman and then on by Sol Katz and has been a
subject for a number of publications on physical
anthropology.

The Fels growth study.
• Sample size:as almost exclusively European with
approximately 2% black subjects.the sample size
was more than 400 subjects and some of them had
history of orthodontic treatment.
• Records:Lateral jaw films,hand wrist x-rays.
• The subjects were first recorded at 3 months with
follow up records every 6 months for 5 years.After
6 years the records were obtained on an annual
basis.

The Fels growth study.
• Lewis et al evaluated pubertal growth spurts in
cranial base and mandible and studied its variation
in individuals based on a sample from the Fels
study.

IMPLANT STUDIES.
• Sample size:36 children of early mixed dentition
stage who presented themselves for orthodontic
consultation.
• Records:Lateral,frontal and 45o
x-ray films.
• The main attribute of the sample was that metallic
implants Bjork type were placed on all subjects
at the onset of observations.
• The subjects were of European origin.
THE MATHEWS IMPLANT COLLECTION.

IMPLANT STUDIES.
• Sample size:consisted of 270 subjects who had
conventional orthodontic treatment at the Oregon
dental school during 1967-1971.
• Records:lateral head films and study casts.
• The subjects had maxillary and mandibular implants of
Bjork type placed before treatment.
• Based on this study Baumrind et al quantified the
differences in the perceived pattern of maxillary
remodeling that are observed when different methods
are used to superimpose maxillary images in
roentgenographic cephalometrics.
THE HIXON OREGON IMPLANT STUDY.

CLEFT PALATE STUDIES.
• LANCASTER PA:includes 850 record sets obtained
annually from birth to 15 years.
• HOSPITAL FOR SICK CHILDREN(Toronto):over
4000 subjects ranging in age from 5-20 years
• .CENTER FOR CRANIOFACIAL
ANOMALIES(Chicago);annual records of 1000
subjects.
• Records include series of x-ray films, casts, medical
and orthodontic treatment records.
• All subjects had surgical repair and minor to extensive
orthodontic treatment.

Teleradiology.
• Concept was introduced in 1982 at
international conference of PACS.
• Universal method of storing and
transporting digital images that can be read
between locations.
• Currently American college of radiology
have developed DICOM to allow the
transmisssion of images over the internet.

Methods of studying bone
growth
c e p h a lo m e tr y .
a n th r o p o m e tr y .
c r a n io m e tr y .
m e a s u r e m e n t a p p r o a c h e s .
a u to r a d io g r a p h y .
n u c le a r v o lu m e m o r p h o m e tr y .
r a d io is o to p e s .
p o la r is e d lig h t.
flu o r e s c e n t la b e ls .
m ic r o r a d io g r a p h y .
m in e r a lis e d s e c tio n s .
a t m ic r o s c o p ic le v e l.
fin ite e le m e n t m o d e lin g .
im p la n t m a r k e r s
a t m a c r o s c o p ic le v e l.
n a tu r a l m a r k e r s .
c o m p a r a tiv e a n a to m y .
v ita l s ta in in g .
a t b o th le v e ls .
e x p e r im e n ta l a p p r o a c h e s .

CRANIOMETRY.
Involves measurements of skull
found among human skeletal
remains.it was originally used to
study the Neanderthal and
Cro-magnon skull. It can give
information of extinct population
and pattern of growth .
Advantages: Precise measurements can be made.
Disadvantages:All growth data must be cross sectional.

• ANTHROPOMETRY:includes measurements
using soft tissue points overlying bony landmarks
in living individuals.it can also be done on dried
skulls but variation in soft tissue thickness would
produce different results.
• Possible to follow the growth of an individual
directly by making the same measurements
repeatedly at different times thus producing
longitudinal data.

• CEPHALOMETRIC RADIOGRAPHY: It allows
direct measurement of bony skeletal dimensions
and also allows the same individual to be followed
over time.
• Disadvantages:Depends upon precise orientation of
head before taking radiographs,requires precise control
of magnification,since it is a 2D representation of 3D
structure all measurements are not possible.www.indiandentalacademy.com

Mineralized sections.
• Fully mineralized sections are superior to
demineralized specimens as there is less processing
distortions and both organic and inorganic matrix can
be studied simultaneously.
• Cellular details and resolutions can be enhanced by
reducing the thickness of the sections.
• Specific stains can be used to enhance both cellular and
extra cellular details.
• Thin sections can however quench more rapidly

Microradiography.
• This gives high resolution of images of bone
sections and show differential density between
primary and secondary bone.
• Strength of the bone is directly related to the
degree of mineralisation.thus secondary bone has
more strength than primary bone.
• Secondary mineralisation process takes about 8
months to form and hence the minimum retention
period after active orthodontic correction should
be 6-8 months.

Fluorescent labels.
• Administered in vivo calcium binding labels are
anabolic time markers of bone formation.
• Mechanism of bone growth is determined by
analysis of label incidence and interlabel
distance.Sequential use of different colored labels
can be used to assess bone growth,healing and
functional adaptation.
• Tetracycline,calcein green,xylenol orange,alizarin
complexone,demeclocycline and oxytetracycline
are some commonly used labels.

Radioisotopes.
• Radioisotopes of certain elements or compounds
are often used as in vivo markers for studying
bone growth.
• Such labeled material is injected and after some
time located within the growing bone by means
of autoradiographic techniques.
• Commonly used markers are :
1. Technetium 99
2. Calcium 45
3. Potassium 32

Autoradiography.
• In this method radioactive precursors for structural
and metabolic materials are detected within tissue by
by coating histological sections with a nuclear track
emulsion.localization of radioactive disintegration
reveals the location of the precursors.
• Specific radioactive labels for protein carbohydrates
or nucleic acids are injected at known interval prior
to tissue sampling.

Autoradiography.
• Quantitative and qualitative assessment of the label uptake
is a physiologic index of cell activity.
• Commonly used autoradiographic labels are:
• A. 3
H thymidine.
• B. 3
H proline.
• C. Bromodeoxyuridine.

Polarized light.
• The lamellar fringe pattern of the bone revealed
with polarized light indicates the orientation of
collagen fibers within the bone matrix.
• Most lamellar bone consists of collagen fibers
oriented at right angles.
• However 2 other configurations can also be
noted:longitudinally aligned(L osteons).

Polarized light.
• And mixed fiber pattern.(both L and A osteons).
• Loading condition at the time of bone formation
dictate the orientation of collagen fibers . Thus
bone formation can adapt to different loading
conditions by changing the internal lamellar
organization of bone tissue.

Nuclear volume morphometry.
• It is a cytomorphometric procedure which
measures the nuclear size for assessing the stages
of differentiation of osteoblastic precursor cells.
• Pre osteoblasts have significantly larger nuclei
than their committed osteoprogenitor precursors
or their osteoblast progeny.
• The method is used in determining the relative
differentiation of PDL and other bone living cells.

Vital staining
• First reported by Belchier in 1796 and also by
John Hunter.they attributed their finding to
alizarin dye.
• One injection of alizarin forms a thin colored line
on all active surfaces of bone growth during the
period in which the dye is in the
bloodstream,hence subsequent depositions are not
colored.

Vital staining.
• The method reveals manner in which bone is laid
down,the sites of bone growth,the direction and
amount of growth,and the timing and relative
duration of growth at different sites.
• Alizarin, tetracycline and procion are dyes which
are used extensively in vital staining in bone
research.

Comparative anatomy.
• Basic principles common to growth in all species
are first recognized and defined by studies in
comparative anatomy.
• Comparisons with such species can lend
significant contributions to our knowledge about
human facial growth.
• Information about phylogeny of the anatomic
components comprising the head has been derived
from comparative studies of fossils and present
day species.

Natural markers.
• The persistence of certain developmental features
has led to their use as natural markers by means of
serial radiography.
• Eg: trabaculae,nutrient canals and lines of arrested
growth can be used for reference to study
deposition, resorption and remodeling.
• Certain natural markers are used as cephalometric
landmarks.

Implant markers.
• Bjork devised a method of implanting tiny bits of
tantalum or biologically inert alloys into growing
bone which served as radiographic reference
markers for serial cephalometric study.
• The method allows precise orientation of serial
cephalograms and information on the amount and
sites of bone growth.

Finite element modeling (FEM).
 It is a analytical method for calculating stresses
and strain within mechanically loaded structures
by breaking the structure down into group of
small elements of known mechanical behavior so
that the response of the entire structure to loading
is estimated.
 The method requires accurate and precise
measurements of known landmarks in the system.
 It utility in analysis of growth and development
has not been tested except to compare its findings
with conventional methods.

REFERENCES:
• Proffit:contemporary orthodontics.
• Moyers:handbook of orthodontics.
• An inventory of United states and Canadian
growth record sets.S.Hunter , Baumrind S
AJO 1993.
• Craniofacial imaging in orthodontics :S
Kapila et al AO 1999:69
• Essays in honour of Robert moyers
CFGS.monograph 24.

References
• Bone biodynamics in
orthodontics:CFGS.27
• Atlas of craniofacial growth in Americans
of African descent CFGS.26
• Growth changes in the nasal profile from 7-
8 yrs AJO 1988:94 Meng H ,R Nanda
• Longitudinal changes in 3 normal facial
types .S Bishara,AJO1985:88
• S Bishara,J R Peterson, changes in the
facial dimensions & relationships between
the ages 5-25yrs.AJO 1984:85

References
• Lewis A B, Roche AF pubertal spurts in
cranial base & mandible AJO 1985:55
• Popovich.Thompson. Craniofacial
templates for orthodontic case analysis.
• Baumrind S,Korn EL,quantitation of
maxillary remodeling. AJO 1987:91
• Atlas of craniofacial growth CFGS
monograph 2.
• Moyers,Van Der Linden standards of
human occlusal development CFGS:5
• B Grayson 3D cephalogram
theory,technique and clinical application.

Growth studies 2

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