Methods of study bone growth /certified fixed orthodontic courses by Indian dental academy


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  • Methods of study bone growth /certified fixed orthodontic courses by Indian dental academy

    1. 1. Methods of studying bone growth INDIAN DENTAL ACADEMY Leader in continuing dental education
    2. 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++
    3. 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
    4. 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
    5. 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
    6. 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 :
    7. 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
    8. 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
    9. 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
    10. 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-
    11. 11. Methods of presenting data Simple tables Graphs (special curves) Charts Bar charts Histograms Pie charts Pictograms Diagrams (pictures)
    12. 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
    13. 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
    14. 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
    15. 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
    16. 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)
    17. 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
    18. 18. Broadbent-Bolton cephalometer
    19. 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
    20. 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
    21. 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
    22. 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
    23. 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
    24. 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
    25. 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
    26. 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
    27. 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
    28. 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
    29. 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
    30. 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
    31. 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
    32. 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
    33. 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
    34. 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
    35. 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
    36. 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
    37. 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
    38. 38. Thank you For more details please visit