this is basic growth and development chapter for undergraduate orthodontics

1. GROWTH & DEVELOPMENT

4. This facetious formulation by Krogman illustrates the complex nature of the biologic process we are to discuss in this chapter

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

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. 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. 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. 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. 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. KEY POINTS Development = Growth + differentiation + translocation.

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. 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. KEY POINTS 9. "Normal" refers to the expected or typical but is misused as a goal of treatment or when confused with the ideal.

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. 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. The stabilization of the adult stage brought about by the growth & development is called Maturation

19. FACTORS AFFECTING PHYSICAL GROWTH

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

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

67. II.Experimental approaches – Bimetric tests E.g. Skeletal maturation & ossification

73. II.Experimental approaches –4.Implants Bjork 1969 Areas where implants were used