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Methods of studying bone
growth
www.indiandentalacademy.com
Bone growth ?
Bone = bone cells(osteoblasts ,osteocytes ,osteoclasts)
+matrix (collagen + calcium hydroxyapatite 65-70%)
Woven bone
Lamellar bone (compact bone)
Composite bone (cancellous bone)
Bundle bone
Vitamin-D 9-11mg/dl Calcitonin
PTH Serum Ca++
www.indiandentalacademy.com
Study
Acquisition of knowledge by investigation.
Collection
of data
Analysis of
this data
Presentation
of data
Explanation
Passion & controversy may have a place in discussion &
interpretation but certainly not in study of rigorously
collected biomedical &clinical data A. G. Petrovic
www.indiandentalacademy.com
Source of data
Census
Registration of vital events
Hospital records & other health records
Survey of population
Health interview survey (opinion)
Health examination survey
Health record survey
mailed question survey
www.indiandentalacademy.com
Types of data
Opinion :it is a clever guess .
Observation :Done to see presence or
absence of certain phenomena
Rating & ranking.
Measurements :Most scientific approch
direct data
indirect data
derived data
www.indiandentalacademy.com
Methods of collecting data
Cross sectional method :based on single
examination of a cross-section of population at
one point in time .
Longitudinal method :observations period
are repeated in the same population over a
prolonged of time by means of follow up
examination.
Semi-longitudinal method :
www.indiandentalacademy.com
Cross-sectional method
ADVANTAGES
easy & quick
less expensive
no attrition of sample
various factors acting
at that time can be
analyzed
can be repeated
DISADVANTAGES
variability with in
the sample
larger size of
sample
factors acting at
various time period
cannot be analyzed
www.indiandentalacademy.com
Longitudinal method
ADVANTAGES
more specific
factors acting at
different time can be
analyzed
less no of subjects
individual variations
DISADVANTAGES
more expensive
difficulty in maintaining
lab & data
more time
attrition of samples
cannot be repeated
Eg Bolton Brush study ,Michigan study ,Iova child welfare study
www.indiandentalacademy.com
Semi-longitudinal method
ADVANTAGES
Tries to combine advantages of both
longitudinal & cross-sectional method.
Data of 15 yrs of study obtained in 3 yrs
DISADVANTAGES
Not as authentic as longitudinal study
www.indiandentalacademy.com
Approach for analysis of
obtained data.
MEASUREMENT
APPROACH
Here animals & humans
are measured without
inducing any change in
them.
Dead/alive
Longitudinal/cross-
sectional
EXPERIMENTAL
APPROACH
Here growth is
manipulated and
observations are
made.
More detailed study.
Mainly animal study.
Longitudinal/cross-
sectionalwww.indiandentalacademy.com
Methods of presenting data
Simple tables
Graphs (special curves)
Charts
Bar charts
Histograms
Pie charts
Pictograms
Diagrams (pictures)
www.indiandentalacademy.com
Explanation concerning craniofacial
growth in current literature
Deductive:logically explained consequence of certain
premises.
Deductivoprobabilistic: tries to relate various items
explained by the deductive explanation with
certain assumptions.Forms basis of D/D
&prognosis.
Functional: Based on single assumption.Generally
Noncolinear relations are seen here .
Phylogenetic:Growth trends explained based on
evolutionary trends.
www.indiandentalacademy.com
Methods of studying bone
growth.
Mineralized sections
Polarized light birefringence
Fluorescent labels
Micro radiography
Auto radiography
nuclear volume morphometry
Cell kinetics
Micro electrodes
 Finite element modeling
Vital staining
Metallic implants
MEASUREMENT
Craniometry
 Comparative
anatomy
Anthropometry
Radiology/Imaging
EXPERIMENTAL
www.indiandentalacademy.com
Craniometry
Measurement of skull of human skeleton.
Broca (1875) defined landmarks &
instruments used for measurements.
Congress of German anthropological
society held at Frankfurt in 1882.
Comparative anatomy
www.indiandentalacademy.com
Anthropometry
Measurement of skeletal dimensions on
living individuals
Physical anthropology :Study of mans
biologic behavior in time and space
Special instruments are used
ADV :Longitudinal study
No harm to subjects
DISADV :Soft tissue error
Operator error
www.indiandentalacademy.com
Radiology /Imaging
Conventional radiographs
Nature and production of x-rays
How does it detect bone growth ?
Films :composition
 size: 22*35 24*40 32*41 57*76 mm 8*10”
:Image formation ,developing & fixing
Intensifying screens (calcium tungstate & rare earth)
Grids (parallel ,focused &Potter Bucky grids.80-100lines/Inch)
www.indiandentalacademy.com
Techniques of
conventional radiography
Intra oral
IOPA
paralleling technique
 Bisecting angle
 Bite wing
occlusal projection
Extra oral
Posterio-anterior
Walters occipitofrontal
Riverse-Towne
sub mento vertex
Lateral oblique mand
Lateral skull
Pt position
Cephalostat
Cephalometry
www.indiandentalacademy.com
Broadbent-Bolton cephalometer
www.indiandentalacademy.com
Cephalometry
ADVANTAGES
Combines advantages of anthropometry
and craniometry that is direct bony
measurement & study of same individual
DISADVANTAGES
2-dimensional
Head position critical
Direction of growth not clear
Panoramic www.indiandentalacademy.com
Specialized radiographic
technique
Digital imaging (CCD -voltage-bits 0-255)
Direct digital radiography (R V G )
Indirect digital radiography
Digital subtraction radiography
Digitized image interpretation
Computed tomography
Magnetic resonance
Radionuclide imaging
Ultrasound
Electronic thermographywww.indiandentalacademy.com
3-D Imaging
3-D analysis would be the ideal way of
analyzing soft/hard tissue profile
Source of data
Multiple video imaging
Sonic digitizing
Laser scanning
Disadv: Pt movement during digitizing
 Primitive soft ware not very accurate
Norms & data not extensivewww.indiandentalacademy.com
Specific experimental
method
Mineralized sections
Polarized light
Fluorescent labels
Micro radiography
Auto radiography
nuclear volume morphometry
Cell kinetics
Micro electrodes
Finite element modeling
Vital staining
Metallic implants
www.indiandentalacademy.com
Histopathological technique
Preparation of tissues for microscopy
Soft tissue embedded in paraffin
Fixation
processing
colloidal embedding - hard tissues(decalcified)
Acid treatment
chelation
Hydrolysis
Ground sections- hard tissues(undecalcified)
Frozen sections for immediate examinationwww.indiandentalacademy.com
Mineralized sections
Critical analysis of tissues as there is less
distortion during processing
Both inorganic mineral & organic matrix can
be studied
100um -tissue level details
25um-Enhanced cellular details
Bone labels quench rapidly
Tissue density inadequate for microradiography
www.indiandentalacademy.com
Polarized light birefringence
Fringe pattern indicate collagen
orientation within bone
Loading conditions during bone formation
dictates orientation of collagen
Longitudinal alignment -Tension
Transverse alignment -compression
www.indiandentalacademy.com
Fluorescent labels
In vivo administration of Cl binders act as
time markers of bone formation
Six fluorescent bone labels are used
Tetracycline -bright yellow
Calcein - green
Xylenol- orange
Alizarin- complexone red
Demeclocyclin- gold
Oxytetracycline- greenish yellowwww.indiandentalacademy.com
Microradiography
Higher resolution images of polished 100um
mineralized sections obtained
1 week primary mineralization
8 months secondary mineralization
Experimental animals analyzed by both
microradiography & using fluoroscentlabels
midfacial sutures PDL
Alveolar process Mandibular condyle
temporal fossawww.indiandentalacademy.com
Autoradiography
Specific radioactive labels for proteins
carbohydrates ,& nucleic acids are injected at
known intervals before sampling
Detected by coating histologic sections with
nuclear track emulsion
 3H thymidine labels DNA synthesis
 3H Proline for bone matrix
www.indiandentalacademy.com
Nuclear volume
morphometry
Cytomorphometric procedure for accessing the
size of osteoblastic precursor cells
Mechanism of osteogenesis in orthodontically
activated PDL
Preosteoblasts have larger nucleus than
committed osteoprogenitor cells and their
precursors
www.indiandentalacademy.com
Cell kinetics
By noting the -increase in nuclear volume
or labeling S-phase cells in vivo using
Bromodeoxyuridine (BDU) cell movement
& differentiation is noted
Generally done in PDL
under normal conditions
under metabolic stimuli
mechanical stimuli
www.indiandentalacademy.com
Microelectrodes
Tungsten or glass electrodes are inserted
atraumatically into PDL in live animals via
gingival sulcus
changes in electric potential are noted
Widened areas have a negative charge
Compressed areas have positive charge
This coincides with the age old principle,
that bone forms near cathode & resorbs
at anode www.indiandentalacademy.com
Finite element modeling
Finite element modeling is a branch of
mechanical engineering where in the stress &
strain of mechanically loaded structures are
analyzed.
Initial stress for periodontium are derived by
assuming linear elastic properties
For complex tissues like periodontium with
viscoelastic properties both solid & fluid
mechanics must be consideredwww.indiandentalacademy.com
Vital staining
Reported initially by Belchier (1796) &
John Hunter where in they attributed
staining to alizarin
This method reveals the site ,manner,
amount , direction ,timing & duration of
bone growth
Tetracycline stains in humans
www.indiandentalacademy.com
Metallic implants
Method of study used extensively by Prof
Bjork & coworkers R D C Copenhagen
They gave new dimension to study of
dentofacial growth.
Remodeling changes in the contours of
jaws was better understood
Rotational pattern of jaw growth
www.indiandentalacademy.com
Conclusion
Tooth movement has been
possible because bone
behaves dynamically
Better understanding of
physiology of bone PDL
interface is necessary
All these methods have
given us the tool for
further study it is up to us
to use it www.indiandentalacademy.com
References
Enlow;Hand book of facial growth, W B Saunders
Company,1982
Orbans:Oral histology &embryology,Delhi, C B S
publishers,1990
Rakosi ,Jones & Graber:Colour atlas of orthodontic
diagnosis,New York,Thieme medical publishers,1993
Farkas L G:Anthropometry of head &face, New York,
Raven press,1994
Jacobson :Radiographic cephalometry,quintessence
books,1995 www.indiandentalacademy.com
Goaz & White:Oral radiology, St Louis,C V Mosby,
1994
K Park : Preventive &social medicine, Jabalpur , M/S
Banarsidas Bhanot,1997
Profitt W R:Contemporary orthodontics,St Louis,C V
Mosby,1997
Graber,Rakosi,Petrovic:Dentofacial orthopedics with
functional appliances, 1997
Graber Vanarsdall:Orthodontics current principles
&technique, St Louis,C V Mosby,2000.
References ctd
Xwww.indiandentalacademy.com

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Sem methods of study bone growth

  • 1. Methods of studying bone growth www.indiandentalacademy.com
  • 2. Bone growth ? Bone = bone cells(osteoblasts ,osteocytes ,osteoclasts) +matrix (collagen + calcium hydroxyapatite 65-70%) Woven bone Lamellar bone (compact bone) Composite bone (cancellous bone) Bundle bone Vitamin-D 9-11mg/dl Calcitonin PTH Serum Ca++ www.indiandentalacademy.com
  • 3. Study Acquisition of knowledge by investigation. Collection of data Analysis of this data Presentation of data Explanation Passion & controversy may have a place in discussion & interpretation but certainly not in study of rigorously collected biomedical &clinical data A. G. Petrovic www.indiandentalacademy.com
  • 4. Source of data Census Registration of vital events Hospital records & other health records Survey of population Health interview survey (opinion) Health examination survey Health record survey mailed question survey www.indiandentalacademy.com
  • 5. Types of data Opinion :it is a clever guess . Observation :Done to see presence or absence of certain phenomena Rating & ranking. Measurements :Most scientific approch direct data indirect data derived data www.indiandentalacademy.com
  • 6. Methods of collecting data Cross sectional method :based on single examination of a cross-section of population at one point in time . Longitudinal method :observations period are repeated in the same population over a prolonged of time by means of follow up examination. Semi-longitudinal method : www.indiandentalacademy.com
  • 7. Cross-sectional method ADVANTAGES easy & quick less expensive no attrition of sample various factors acting at that time can be analyzed can be repeated DISADVANTAGES variability with in the sample larger size of sample factors acting at various time period cannot be analyzed www.indiandentalacademy.com
  • 8. Longitudinal method ADVANTAGES more specific factors acting at different time can be analyzed less no of subjects individual variations DISADVANTAGES more expensive difficulty in maintaining lab & data more time attrition of samples cannot be repeated Eg Bolton Brush study ,Michigan study ,Iova child welfare study www.indiandentalacademy.com
  • 9. Semi-longitudinal method ADVANTAGES Tries to combine advantages of both longitudinal & cross-sectional method. Data of 15 yrs of study obtained in 3 yrs DISADVANTAGES Not as authentic as longitudinal study www.indiandentalacademy.com
  • 10. Approach for analysis of obtained data. MEASUREMENT APPROACH Here animals & humans are measured without inducing any change in them. Dead/alive Longitudinal/cross- sectional EXPERIMENTAL APPROACH Here growth is manipulated and observations are made. More detailed study. Mainly animal study. Longitudinal/cross- sectionalwww.indiandentalacademy.com
  • 11. Methods of presenting data Simple tables Graphs (special curves) Charts Bar charts Histograms Pie charts Pictograms Diagrams (pictures) www.indiandentalacademy.com
  • 12. Explanation concerning craniofacial growth in current literature Deductive:logically explained consequence of certain premises. Deductivoprobabilistic: tries to relate various items explained by the deductive explanation with certain assumptions.Forms basis of D/D &prognosis. Functional: Based on single assumption.Generally Noncolinear relations are seen here . Phylogenetic:Growth trends explained based on evolutionary trends. www.indiandentalacademy.com
  • 13. Methods of studying bone growth. Mineralized sections Polarized light birefringence Fluorescent labels Micro radiography Auto radiography nuclear volume morphometry Cell kinetics Micro electrodes  Finite element modeling Vital staining Metallic implants MEASUREMENT Craniometry  Comparative anatomy Anthropometry Radiology/Imaging EXPERIMENTAL www.indiandentalacademy.com
  • 14. Craniometry Measurement of skull of human skeleton. Broca (1875) defined landmarks & instruments used for measurements. Congress of German anthropological society held at Frankfurt in 1882. Comparative anatomy www.indiandentalacademy.com
  • 15. Anthropometry Measurement of skeletal dimensions on living individuals Physical anthropology :Study of mans biologic behavior in time and space Special instruments are used ADV :Longitudinal study No harm to subjects DISADV :Soft tissue error Operator error www.indiandentalacademy.com
  • 16. Radiology /Imaging Conventional radiographs Nature and production of x-rays How does it detect bone growth ? Films :composition  size: 22*35 24*40 32*41 57*76 mm 8*10” :Image formation ,developing & fixing Intensifying screens (calcium tungstate & rare earth) Grids (parallel ,focused &Potter Bucky grids.80-100lines/Inch) www.indiandentalacademy.com
  • 17. Techniques of conventional radiography Intra oral IOPA paralleling technique  Bisecting angle  Bite wing occlusal projection Extra oral Posterio-anterior Walters occipitofrontal Riverse-Towne sub mento vertex Lateral oblique mand Lateral skull Pt position Cephalostat Cephalometry www.indiandentalacademy.com
  • 19. Cephalometry ADVANTAGES Combines advantages of anthropometry and craniometry that is direct bony measurement & study of same individual DISADVANTAGES 2-dimensional Head position critical Direction of growth not clear Panoramic www.indiandentalacademy.com
  • 20. Specialized radiographic technique Digital imaging (CCD -voltage-bits 0-255) Direct digital radiography (R V G ) Indirect digital radiography Digital subtraction radiography Digitized image interpretation Computed tomography Magnetic resonance Radionuclide imaging Ultrasound Electronic thermographywww.indiandentalacademy.com
  • 21. 3-D Imaging 3-D analysis would be the ideal way of analyzing soft/hard tissue profile Source of data Multiple video imaging Sonic digitizing Laser scanning Disadv: Pt movement during digitizing  Primitive soft ware not very accurate Norms & data not extensivewww.indiandentalacademy.com
  • 22. Specific experimental method Mineralized sections Polarized light Fluorescent labels Micro radiography Auto radiography nuclear volume morphometry Cell kinetics Micro electrodes Finite element modeling Vital staining Metallic implants www.indiandentalacademy.com
  • 23. Histopathological technique Preparation of tissues for microscopy Soft tissue embedded in paraffin Fixation processing colloidal embedding - hard tissues(decalcified) Acid treatment chelation Hydrolysis Ground sections- hard tissues(undecalcified) Frozen sections for immediate examinationwww.indiandentalacademy.com
  • 24. Mineralized sections Critical analysis of tissues as there is less distortion during processing Both inorganic mineral & organic matrix can be studied 100um -tissue level details 25um-Enhanced cellular details Bone labels quench rapidly Tissue density inadequate for microradiography www.indiandentalacademy.com
  • 25. Polarized light birefringence Fringe pattern indicate collagen orientation within bone Loading conditions during bone formation dictates orientation of collagen Longitudinal alignment -Tension Transverse alignment -compression www.indiandentalacademy.com
  • 26. Fluorescent labels In vivo administration of Cl binders act as time markers of bone formation Six fluorescent bone labels are used Tetracycline -bright yellow Calcein - green Xylenol- orange Alizarin- complexone red Demeclocyclin- gold Oxytetracycline- greenish yellowwww.indiandentalacademy.com
  • 27. Microradiography Higher resolution images of polished 100um mineralized sections obtained 1 week primary mineralization 8 months secondary mineralization Experimental animals analyzed by both microradiography & using fluoroscentlabels midfacial sutures PDL Alveolar process Mandibular condyle temporal fossawww.indiandentalacademy.com
  • 28. Autoradiography Specific radioactive labels for proteins carbohydrates ,& nucleic acids are injected at known intervals before sampling Detected by coating histologic sections with nuclear track emulsion  3H thymidine labels DNA synthesis  3H Proline for bone matrix www.indiandentalacademy.com
  • 29. Nuclear volume morphometry Cytomorphometric procedure for accessing the size of osteoblastic precursor cells Mechanism of osteogenesis in orthodontically activated PDL Preosteoblasts have larger nucleus than committed osteoprogenitor cells and their precursors www.indiandentalacademy.com
  • 30. Cell kinetics By noting the -increase in nuclear volume or labeling S-phase cells in vivo using Bromodeoxyuridine (BDU) cell movement & differentiation is noted Generally done in PDL under normal conditions under metabolic stimuli mechanical stimuli www.indiandentalacademy.com
  • 31. Microelectrodes Tungsten or glass electrodes are inserted atraumatically into PDL in live animals via gingival sulcus changes in electric potential are noted Widened areas have a negative charge Compressed areas have positive charge This coincides with the age old principle, that bone forms near cathode & resorbs at anode www.indiandentalacademy.com
  • 32. Finite element modeling Finite element modeling is a branch of mechanical engineering where in the stress & strain of mechanically loaded structures are analyzed. Initial stress for periodontium are derived by assuming linear elastic properties For complex tissues like periodontium with viscoelastic properties both solid & fluid mechanics must be consideredwww.indiandentalacademy.com
  • 33. Vital staining Reported initially by Belchier (1796) & John Hunter where in they attributed staining to alizarin This method reveals the site ,manner, amount , direction ,timing & duration of bone growth Tetracycline stains in humans www.indiandentalacademy.com
  • 34. Metallic implants Method of study used extensively by Prof Bjork & coworkers R D C Copenhagen They gave new dimension to study of dentofacial growth. Remodeling changes in the contours of jaws was better understood Rotational pattern of jaw growth www.indiandentalacademy.com
  • 35. Conclusion Tooth movement has been possible because bone behaves dynamically Better understanding of physiology of bone PDL interface is necessary All these methods have given us the tool for further study it is up to us to use it www.indiandentalacademy.com
  • 36. References Enlow;Hand book of facial growth, W B Saunders Company,1982 Orbans:Oral histology &embryology,Delhi, C B S publishers,1990 Rakosi ,Jones & Graber:Colour atlas of orthodontic diagnosis,New York,Thieme medical publishers,1993 Farkas L G:Anthropometry of head &face, New York, Raven press,1994 Jacobson :Radiographic cephalometry,quintessence books,1995 www.indiandentalacademy.com
  • 37. Goaz & White:Oral radiology, St Louis,C V Mosby, 1994 K Park : Preventive &social medicine, Jabalpur , M/S Banarsidas Bhanot,1997 Profitt W R:Contemporary orthodontics,St Louis,C V Mosby,1997 Graber,Rakosi,Petrovic:Dentofacial orthopedics with functional appliances, 1997 Graber Vanarsdall:Orthodontics current principles &technique, St Louis,C V Mosby,2000. References ctd Xwww.indiandentalacademy.com