GROWTH STUDIES AND METHODS OF STUDYING GROWTH.
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Types of growth data
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Methods of gathering growth data
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Longitudinal growth studies
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Methods of studying bone growth www.indiandentalacademy.com
Types of growth data. Opinion Observations. Ratings and rankings. Quantitative measurements. direct data. indirect data. derived data.
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Types of growth 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. www.indiandentalacademy.com
Types of growth data. • 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.
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Types of growth data. • 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.
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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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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.
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LONGITUDINAL GROWTH STUDIES.
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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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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 www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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 525 yrs of age was described & compared.
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The Forsyth twin study. AIM:the study observed the dental ,somatic and facial development of 414 pairs of twins.
• 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. www.indiandentalacademy.com
The Meharry growth study AIM:was to study the craniofacial growth and form in the African Americans using serial radiographic cephalometrics. • 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. www.indiandentalacademy.com
The Montreal growth study. AIM:To make available a reference data necessary to perform growth assessments/predictions • 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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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.
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IMPLANT STUDIES. THE MATHEWS IMPLANT COLLECTION. • 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. www.indiandentalacademy.com
IMPLANT STUDIES. THE HIXON OREGON IMPLANT STUDY. • 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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
Methods of studying bone growth m e a s u re m e n t a p p ro a c h e s .
e x p e r im e n t a l a p p r o a c h e s .
c r a n io m e t r y .
a t m ic r o s c o p ic le v e l.
a t m a c r o s c o p ic le v e l.
a t b o t h le v e ls .
a n th ro p o m e try .
m in e r a lis e d s e c t io n s .
im p la n t m a r k e r s
v it a l s t a in in g .
c e p h a lo m e t r y .
m ic r o r a d io g r a p h y .
f in it e e le m e n t m o d e lin g .
c o m p a r a t iv e a n a t o m y .
f lu o r e s c e n t la b e ls . p o la r is e d lig h t . r a d io is o t o p e s . n u c le a r v o lu m e m o r p h o m e t r y . a u t o r a d iowww.indiandentalacademy.com g ra p h y .
n a tu ra l m a rk e rs .
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. www.indiandentalacademy.com
• 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.
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• 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 www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. 2. 3.
Technetium 99 Calcium 45 Potassium 32 www.indiandentalacademy.com
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.
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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.
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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).
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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.
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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. www.indiandentalacademy.com
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.
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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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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.
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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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
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 78 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 www.indiandentalacademy.com
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. www.indiandentalacademy.com
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