Several other disease processes involve both inflammation and bone uncoupling. For example, similar to periodontal disease, osteoporosis is also characterized by uncoupling due to deficient bone formation following bone resorption. list of molecules that could mediate the effects of inflammation on uncoupling is provided in Table 2. Although this review focuses on bone, it is recognized that, for periodontal regeneration to occur, the formation of new cementum and periodontal ligament must also take place (Foster et al., 2007).
Lenneberg (1967) sees the critical period starting at the age of 2 and ending around puberty, a period, which coincides with the brain lateralisation process, which is the specialisation of the dominant hemisphere of the brain language functions. Lenneberg (1967) cited a wide evidence of changes in the brain taking place during this period.
The embryo is most susceptible to teratogenic agents. during periods of rapid differentiation. The stage of development of the embryo determines suscep-. tibility to teratogens. The most critical period in the development of an embryo or in the growth of a. particular organ is during the time of most rapid cell division. The critical period for each organ is. pictured below (Fig. 23-2). For instance, the critical period for brain growth and development is. from three to 16 weeks.