Growth & Development1 Theory Class for dental undergraduates

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this is basic growth and development chapter for undergraduate orthodontics

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Growth & Development1 Theory Class for dental undergraduates

  1. 1. GROWTH & DEVELOPMENT
  2. 2. THE PRACTICE OF ORTHODONTICS HAS TWO BASIC REQUIREMENTS <ul><li>Intimate knowledge of the anatomy and growth of the head </li></ul><ul><li>Master the techniques for regulating tooth position </li></ul>
  3. 3. <ul><li>As orthodontists we should have the concepts of when, where, why and how the facial growth occurs. The role the genetic and environmental factors in influencing facial growth </li></ul><ul><li>it is necessary to have a thorough understanding of both the pattern of normal growth and the mechanisms that underlie it and deviations from normal pattern. it is important to distinguish normal variation from the effects of abnormal or pathologic processes </li></ul><ul><li>How the face changes from its embryologic form through childhood, adolescence and adulthood. </li></ul><ul><li>Understanding of how and where the growth occurs, direction of growth , how much growth potential is remaining and when the growth will express itself., </li></ul><ul><li>How the above factors can be modified by the operator for the benefit of the patient and to achieve the optimal results in the potential of each individual person. </li></ul>
  4. 4. This facetious formulation by Krogman illustrates the complex nature of the biologic process we are to discuss in this chapter
  5. 5. Growth was conceived by an anatomist. born to a biologist, delivered by a physician,left on a chemist’s doorstep,and adopted by a physiologist . At an early age she eloped with a statistician, divorced him. for a psychologist, and is now being wooed, alternately and concurrently,by an endocrinologist a pediatrician , a physical anthropologist, an educationalist, a biochemist, a physicist, mathematician, an orthodontist, a eugenicist & the Children's Bureau
  6. 6. <ul><ul><ul><li>Definitions related to Growth </li></ul></ul></ul>J.S. Huxley “ The self multiplication of living substance.” Krogman “ Increase in size, change in proportion and progressive complexity.” Todd “ An increase in size.” Meridith - “ Entire series of sequential anatomic and physiologic changes taking place from the beginning of prenatal life to senility. Moyers “ Quantitative aspect of biologic development per unit of time.” Moss Change in any morphological parameter which is measurable profit Growth refers to an increase in size/number
  7. 7. Generally growth is irreversible. It is partially true as in the in the case of increase in the length of the body. Growth may be reversible as seen in the case of increase in weight of the body . Though growth is generally associated with an increase in size and unidirectional , yet some conditions involving regression are also considered to take place during growth. For example, the atrophy of the thymus gland
  8. 8. Though growth is generally associated with an increase in size, yet some conditions involving regression are also considered to take place during growth. E.g. The atrophy of the thymus gland.
  9. 9. DEVELOPMENT – G ROWTH IS OFTEN USED AS A SYNONYMOUS FOR DEVELOPMENT. BIOLOGICALLY DEVELOPMENT IS A PROCESS OF CONTINUOUS CHANGES OCCURRING IN A PREDETERMINED DIRECTION. Thus it encompasses the normal sequential events between fertilization and death. Todd “ Development,” according to Todd, “is progress towards maturity”. Profit Development is in complexity Moyers According to Moyers, development refers to all the naturally occurring unidirectional changes in the life of an individual from its existence as a single cell to its elaboration as a multifunctional unit terminating in death.
  10. 10. Development Development refers to all the naturally occurring unidirectional changes in the life of an individual from its existence as a single cell to its elaboration as a multifunctional unit terminating in death.
  11. 11. Differentiation Differentiation is the change from a generalized cell or tissue to one that is more specialized. Thus differentiation is a change in quality or kind. According to Todd' growth and development relies on the other and under the influence of morphogenetic pattern; the threefold process works its miracles; self-multiplication, differentiation, organization -each according to its own kind! A fourth dimension is time.
  12. 12. KEY POINTS Development = Growth + differentiation + translocation.
  13. 13. KEY POINTS Development is characterized by changes in complexity, a shift to fixation of function, and more independence, all of which is under genetic control, yet modified by the environment
  14. 14. The changes associated with aging i.e.,degeneration and senility are considered by some as a part of maturation, while others consider It as part of development.
  15. 15. KEY POINTS 9. &quot;Normal&quot; refers to the expected or typical but is misused as a goal of treatment or when confused with the ideal.
  16. 16. KEY POINTS 10. Growth is evaluated in chincal practice to assess the status of the patient, recognize any pathologic deviations, and plan treatment.
  17. 17. Differentiation Differentiation is the change from a generalized cell or tissue to one that is more specialized. Thus differentiation is a change in quality or kind.
  18. 18. The stabilization of the adult stage brought about by the growth & development is called Maturation
  19. 19. FACTORS AFFECTING PHYSICAL GROWTH
  20. 20. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Heredity. </li></ul><ul><li>Nutrition. </li></ul><ul><li>Illness. </li></ul><ul><li>Race </li></ul><ul><li>Socio- economic factors </li></ul>
  21. 21. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Family size and birth order </li></ul><ul><li>Secular trends </li></ul><ul><li>Climatic and seasonal effects </li></ul><ul><li>Psychological disturbances </li></ul><ul><li>Exercise </li></ul>
  22. 22. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Heredity. </li></ul>The size of parts,Rate of growth and the Onset of growth. The genes hence play a major role in the overall growth of a person. Studies were done on twins
  23. 23. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Nutrition. </li></ul>Malnutrition may affect all aspects of growth including size of parts, body proportions, quality and texture of tissues, and onset of growth events.
  24. 24. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Nutrition. </li></ul><ul><ul><ul><li>The effects of malnutrition are reversible to a certain extent as children have fine recuperative powers. </li></ul></ul></ul>
  25. 25. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Nutrition. </li></ul><ul><ul><ul><li>Catch-up growth </li></ul></ul></ul><ul><li>If the adverse effects are not too severe, the growth process accelerates when proper nutrition is provided. </li></ul>
  26. 26. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Illness. </li></ul><ul><ul><ul><li>The usual minor childhood illness </li></ul></ul></ul><ul><ul><ul><li>ordinarily cannot be shown to have </li></ul></ul></ul><ul><ul><ul><li>much effect on physical growth. </li></ul></ul></ul><ul><ul><ul><li>Prolonged and debilitating illness </li></ul></ul></ul><ul><ul><ul><li>however can have a marked effect on </li></ul></ul></ul><ul><ul><ul><li>all aspects of growth. </li></ul></ul></ul>
  27. 27. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Race </li></ul><ul><ul><ul><li>Differences in growth among different races can be attributed to other Nutritional and environmental factors, </li></ul></ul></ul>
  28. 28. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Socio- economic factors </li></ul><ul><ul><ul><li>Children brought up in affluent and </li></ul></ul></ul><ul><ul><ul><li>favorable socio-economic conditions </li></ul></ul></ul><ul><ul><ul><li>show earlier onset of growth events. </li></ul></ul></ul><ul><ul><ul><li>They also grow to a larger size than </li></ul></ul></ul><ul><ul><ul><li>children living in unfavorable socio- </li></ul></ul></ul><ul><ul><ul><li>economic environment. </li></ul></ul></ul>
  29. 29. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Family size and birth order </li></ul><ul><ul><ul><li>First born babies tend to weigh less at birth and have smaller stature but higher I. Q. </li></ul></ul></ul><ul><ul><ul><li>The smaller the family size, the better would be the nutrition and other favorable conditions. </li></ul></ul></ul>
  30. 30. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Secular trends </li></ul><ul><ul><ul><li>Changes in size and maturation in a </li></ul></ul></ul><ul><ul><ul><ul><li>large population can be shown to occur </li></ul></ul></ul></ul><ul><ul><ul><li>with time. </li></ul></ul></ul><ul><ul><ul><li>e.g :15 old boys are approximately 5 inches taller than the same age group 50 years back. </li></ul></ul></ul>
  31. 31. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Secular trends </li></ul><ul><ul><ul><ul><li>It could possibly be due to changes in socio-economic conditions and food habits. </li></ul></ul></ul></ul>
  32. 32. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Climatic and seasonal effects </li></ul><ul><ul><ul><li>Seasonal variation have been shown to </li></ul></ul></ul><ul><ul><ul><li>affect adipose tissue content and the weight of new born babies. </li></ul></ul></ul><ul><ul><ul><li>Climatic changes seem to have little direct effect on rate of growth. </li></ul></ul></ul>
  33. 33. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Psychological disturbances </li></ul><ul><ul><ul><li>Children experiencing stressful conditions display an inhibition of growth hormone secretion . </li></ul></ul></ul><ul><ul><ul><li>Psychological disturbances of prolonged </li></ul></ul></ul><ul><ul><ul><li>duration can hence markedly retard </li></ul></ul></ul><ul><ul><ul><li>growth. </li></ul></ul></ul>
  34. 34. FACTORS AFFECTING PHYSICAL GROWTH <ul><li>Exercise </li></ul><ul><ul><ul><li>Exercises are essential for a healthy body, Strenuous and regular exercises have not been associated with more favorable growth. </li></ul></ul></ul><ul><ul><ul><li>Certain aspects of growth such as development of some motor skills and increase in muscle mass is found to be influenced by exercise. </li></ul></ul></ul>
  35. 35. <ul><li>BASIC TENETS OF GROWTH </li></ul><ul><li>PATTERN </li></ul><ul><li>VARIABILITY </li></ul><ul><li>TIMING </li></ul>
  36. 36. CONCEPTS OF GROWTH <ul><ul><ul><li>Concept of normality </li></ul></ul></ul><ul><ul><ul><li>Normal refers to that which is usually </li></ul></ul></ul><ul><ul><ul><li>expected, is ordinarily seen or is typical. </li></ul></ul></ul>
  37. 37. CONCEPTS OF GROWTH <ul><ul><ul><li>Concept of normality </li></ul></ul></ul><ul><ul><ul><li>The concept of normality must not be </li></ul></ul></ul><ul><ul><ul><li>equated with that of the ideal. While </li></ul></ul></ul><ul><ul><ul><li>ideal denotes the central tendency for </li></ul></ul></ul><ul><ul><ul><li>the group. </li></ul></ul></ul>
  38. 38. CONCEPTS OF GROWTH <ul><ul><ul><li>Concept of normality </li></ul></ul></ul><ul><ul><ul><li>Normal refers to a range Another aspect of cranio facial growth is that normality changes with age. </li></ul></ul></ul>
  39. 39. CONCEPTS OF GROWTH <ul><ul><ul><li>Rhythm of growth </li></ul></ul></ul><ul><ul><ul><li>Hooton </li></ul></ul></ul><ul><ul><ul><li>Human growth is not a steady & uniform </li></ul></ul></ul><ul><ul><ul><li>process wherein all parts of die body enlarge </li></ul></ul></ul><ul><ul><ul><li>at the same rate & the increments of one year </li></ul></ul></ul><ul><li>arc equal to that of the proceeding </li></ul><ul><li>or succeeding year.&quot; </li></ul>
  40. 40. CONCEPTS OF GROWTH <ul><ul><ul><li>Rhythm of growth </li></ul></ul></ul><ul><ul><ul><li>This growth rhythm is </li></ul></ul></ul><ul><ul><ul><li>most clearly seen in </li></ul></ul></ul><ul><ul><ul><li>stature or body height. </li></ul></ul></ul>
  41. 41. CONCEPTS OF GROWTH <ul><ul><ul><li>Rhythm of growth </li></ul></ul></ul><ul><ul><ul><li>The first &quot;wave&quot; of growth is seen </li></ul></ul></ul><ul><ul><ul><li>in both sexes from birth to the fifth or </li></ul></ul></ul><ul><ul><ul><li>sixth year </li></ul></ul></ul>
  42. 42. CONCEPTS OF GROWTH <ul><ul><ul><li>Rhythm of growth </li></ul></ul></ul><ul><ul><ul><li>It is most intense and rapid </li></ul></ul></ul><ul><ul><ul><li>during the first 2 years. </li></ul></ul></ul><ul><ul><ul><li>There follows a slower increase </li></ul></ul></ul><ul><ul><ul><li>terminating in </li></ul></ul></ul><ul><ul><ul><li>Boys -10 th to 12 th year </li></ul></ul></ul><ul><ul><ul><li>Girls -no later than 10 th year. </li></ul></ul></ul>
  43. 43. CONCEPTS OF GROWTH <ul><ul><ul><li>Rhythm of growth </li></ul></ul></ul><ul><ul><ul><li>Both sexes </li></ul></ul></ul><ul><ul><ul><li>another period of accelerated growth </li></ul></ul></ul><ul><ul><ul><li>corresponding to adolescence </li></ul></ul></ul><ul><ul><ul><li>Girls 14 th and 16 th year </li></ul></ul></ul><ul><ul><ul><li>Boys 16 th or 18 th year. </li></ul></ul></ul>
  44. 44. CONCEPTS OF GROWTH <ul><ul><ul><li>Growth Spurt </li></ul></ul></ul><ul><ul><ul><li>Sudden increase in growth </li></ul></ul></ul><ul><ul><ul><li>is termed </li></ul></ul></ul><ul><ul><ul><ul><li>&quot;growth spurt&quot;. </li></ul></ul></ul></ul>
  45. 45. CONCEPTS OF GROWTH <ul><ul><ul><li>Growth Spurt </li></ul></ul></ul><ul><ul><ul><ul><li>&quot;Growth Spurt&quot;. </li></ul></ul></ul></ul><ul><ul><ul><li>Periods when </li></ul></ul></ul><ul><ul><ul><li>a sudden acceleration </li></ul></ul></ul><ul><ul><ul><li>of growth occurs. </li></ul></ul></ul>
  46. 46. CONCEPTS OF GROWTH <ul><ul><ul><li>Growth Spurt </li></ul></ul></ul><ul><ul><ul><li>physiological alteration in </li></ul></ul></ul><ul><ul><ul><li>hormonal secretion </li></ul></ul></ul><ul><ul><ul><li>cause for Growth Spurts </li></ul></ul></ul>
  47. 47. CONCEPTS OF GROWTH <ul><ul><ul><li>Growth Spurt </li></ul></ul></ul><ul><ul><ul><li>TIMINGS OF GROWTH SPURTS. </li></ul></ul></ul><ul><ul><ul><li>Just before birth </li></ul></ul></ul><ul><ul><ul><li>One year after birth </li></ul></ul></ul><ul><ul><ul><li>Mixed dentition growth spurt </li></ul></ul></ul><ul><ul><ul><li>Boys : 8-11 years </li></ul></ul></ul><ul><ul><ul><li>Girls : 7-9 years </li></ul></ul></ul><ul><ul><ul><li>Pre-Pubertal growth spurt </li></ul></ul></ul><ul><ul><ul><li>Boys : 14 - 16 years </li></ul></ul></ul><ul><ul><ul><li>Girls : 11-13 years </li></ul></ul></ul>
  48. 48. CONCEPTS OF GROWTH <ul><ul><ul><li>Growth Spurt </li></ul></ul></ul><ul><ul><ul><li>Growth modification </li></ul></ul></ul><ul><ul><ul><li>by means of </li></ul></ul></ul><ul><ul><ul><li>Functional and </li></ul></ul></ul><ul><ul><ul><li>orthodontic appliances </li></ul></ul></ul><ul><ul><ul><li>Elicit better response </li></ul></ul></ul><ul><ul><ul><li>during growth spurts. </li></ul></ul></ul>
  49. 49. CONCEPTS OF GROWTH <ul><ul><ul><li>Differential growth </li></ul></ul></ul><ul><ul><ul><li>Different organs grow </li></ul></ul></ul><ul><ul><ul><li>at different rates </li></ul></ul></ul><ul><ul><ul><li>to a different amount </li></ul></ul></ul><ul><ul><ul><li>& </li></ul></ul></ul><ul><ul><ul><li>at different times. </li></ul></ul></ul>
  50. 50. CONCEPTS OF GROWTH <ul><ul><ul><li>Differential growth </li></ul></ul></ul><ul><ul><ul><li>Scammon's curve of growth </li></ul></ul></ul><ul><ul><ul><li>2. Cephalo-caudal gradient of growth </li></ul></ul></ul>
  51. 51. 1. General or Somatic curve height, weight, skeleton, muscles 2. Genital slow in the pre-pubertal period rapid at adolescence 3. Neural curve brain, skull, eyes, ears development earlier than any other tissues or organs no adolescent spurt 4. Lymphoid curve tonsils, adenoids, appendix, intestines, and spleen pre-adolescent maximum, followed by regression to adult value
  52. 52. <ul><li>Lymphoid curve Lymphoid tissue proliferates rapidly in late childhood and reaches almost 200% of adult size </li></ul><ul><ul><ul><li>An adaptation to protect children from infection </li></ul></ul></ul><ul><ul><ul><li>By 18 years LYMPHOID tissue undergoes involution to reach adult size. </li></ul></ul></ul>
  53. 53. <ul><li>Neural curve </li></ul><ul><li>Neural tissue grows very rapidly and reaches adult size by 6-7 years. </li></ul><ul><li>Very little growth of neural tissue occurs after 6-7 years. </li></ul>
  54. 54. <ul><li>General or Somatic curve </li></ul><ul><li>Consists of the muscles, bones and other organs. </li></ul><ul><li>These tissues exhibit an &quot;S&quot; shaped curve with rapid growth up to 2-3 years </li></ul>
  55. 55. followed by a slow phase of growth between 3-10 years. After the 10 th year, a rapid phase of growth occurs terminating by the 18 - 20th year
  56. 56. <ul><li>Genital slow in the pre-pubertal period rapid at adolescence </li></ul>
  57. 57. CONCEPTS OF GROWTH <ul><ul><ul><li>2. Cephalo-caudal gradient of growth </li></ul></ul></ul><ul><ul><ul><li>An axis of </li></ul></ul></ul><ul><ul><ul><li>increased growth </li></ul></ul></ul><ul><ul><ul><li>extending from </li></ul></ul></ul><ul><ul><ul><li>head towards </li></ul></ul></ul><ul><ul><ul><li>the feet </li></ul></ul></ul>
  58. 59. CONCEPTS OF GROWTH <ul><ul><ul><li>2. Cephalo-caudal gradient of growth </li></ul></ul></ul><ul><ul><ul><li>A comparison of the </li></ul></ul></ul><ul><ul><ul><li>body proportion </li></ul></ul></ul><ul><ul><ul><li>Between pre-natal and </li></ul></ul></ul><ul><ul><ul><li>post-natal life </li></ul></ul></ul><ul><ul><ul><li>reveals Post-natal growth </li></ul></ul></ul><ul><ul><ul><li>of regions of the </li></ul></ul></ul><ul><ul><ul><li>body that are away from </li></ul></ul></ul><ul><ul><ul><li>the HYPOPHYSIS is more . </li></ul></ul></ul>
  59. 60. CONCEPTS OF GROWTH <ul><ul><ul><li>Cephalo-caudal gradient of growth </li></ul></ul></ul><ul><ul><ul><li>3 rd month of intra-uterine life :The head takes up 50% of the total body length. </li></ul></ul></ul><ul><ul><ul><li>At birth :the trunk and the limbs have grown more than the head, thereby reducing the head to about 30% of body length. </li></ul></ul></ul><ul><ul><ul><li>The growth continues with a progressive reduction in the relative size of the head to about 12% in the adult </li></ul></ul></ul>
  60. 62. METHODS OF GATHERING GROWTH DATA <ul><li>Longitudinal Studies </li></ul><ul><li>Cross sectional studies </li></ul><ul><li>Semi - longitudinal studies </li></ul>
  61. 63. METHODS OF STUDYING GROWTH <ul><ul><ul><li>I .Measurement approaches </li></ul></ul></ul><ul><ul><ul><li>II.Experimental approaches </li></ul></ul></ul>Proffit
  62. 64. METHODS OF STUDYING GROWTH <ul><ul><ul><li>I .Measurement approaches </li></ul></ul></ul><ul><ul><ul><li>Living individuals </li></ul></ul></ul>Proffit
  63. 65. METHODS OF STUDYING GROWTH <ul><ul><ul><li>I .Measurement approaches </li></ul></ul></ul>Proffit
  64. 66. METHODS OF STUDYING GROWTH <ul><ul><ul><li>E.g . Height, Weight , Skeletal maturation & ossification </li></ul></ul></ul><ul><ul><ul><li>Compared with standards </li></ul></ul></ul>Proffit II.Experimental approaches -Bimetric tests
  65. 67. II.Experimental approaches – Bimetric tests E.g. Skeletal maturation & ossification
  66. 68. II.Experimental approaches –2.vital staining Belchier 1936 <ul><ul><ul><li>accidentally noted that bones of animals who had eaten madder plants were stained red. </li></ul></ul></ul>
  67. 69. II.Experimental approaches –2.vital staining Belchier 1936 <ul><ul><ul><li>dye in the madder plant, ALIZARIN was identified and used for bone research. </li></ul></ul></ul>
  68. 70. II.Experimental approaches –2.vital staining <ul><ul><ul><li>site of growth, </li></ul></ul></ul><ul><ul><ul><li>the direction, </li></ul></ul></ul><ul><ul><ul><li>duration and amount of growth </li></ul></ul></ul>
  69. 71. II.Experimental approaches –2.vital staining <ul><ul><ul><li>Other dyes used </li></ul></ul></ul><ul><ul><ul><li>Acid Alizarin Blue </li></ul></ul></ul><ul><ul><ul><li>Trypon blue </li></ul></ul></ul><ul><ul><ul><li>Lead acetate </li></ul></ul></ul><ul><ul><ul><li>Tetracycline </li></ul></ul></ul>
  70. 72. II.Experimental approaches –3.Radioisotopes <ul><ul><ul><li>Technetium 33 </li></ul></ul></ul><ul><ul><ul><li>Calcium 45 </li></ul></ul></ul><ul><ul><ul><li>Potassium 32 </li></ul></ul></ul>
  71. 73. II.Experimental approaches –4.Implants Bjork 1969 Areas where implants were used

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