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Adequate nutritional status prior to and during pregnancy supports the development of oral health in infants and children Recommended infant feeding practices, introduction of foods, and healthful dietary choices promote optimum growth and development and decreased risk of early childhood caries Caries in children is associated with multiple dietary factors including frequent fermentable carbohydrate consumption Poor oral health in children with childhood disorders and diseases is associated with possible increased risk for malnutrition and growth impairment [ABSTRACT FROM AUTHOR]

Much is now known of the molecular signalling and genetic determinants for tooth development. Here, we discuss the current understanding of the cellular origin of teeth, the early patterning that determines where a tooth is positioned in the mouth, how the tooth initiates, and the number of the teeth that will form in mouse. The genes that are important for regulating the tooth shape are also discussed. [ABSTRACT FROM AUTHOR]

Introduction The dentition has long been, and still is, important to vertebrate biologists: to palaeontologists, because teeth often represent the sole fossil evidence available; to taxonomists, because of the estimated high taxonomic value of teeth; and to developmental biologists, because teeth provide an excellent experimental model to test developmental principles. Yet, relatively little attention has been paid in these various disciplines to intraspecific variation and the relative roles played by the genome and the environment to generate this variation. Can developmental processes leading to a species-specific, predictable outcome (i.e. a dental unit of specific size, shape, etc.) be modified in the course of an organism's ontogeny by changes in the external environment to produce a unit of different size, shape, etc., with respect to what is ‘normal’ for the species? In other words can the dentition exhibit environmentally induced phenotypic variation? The subject of phenotypic plasticity has gained much interest in vertebrate biology in the past 15 years. Phenotypic plasticity, as opposed to genetic polymorphism, covers all types of environmentally induced phenotypic variation (Stearns, 1989) and is defined as the ability of an individual to respond to changes in the environment in terms of its anatomy, physiological state and/or behaviour (Smits, 1996). In this chapter I am primarily concerned with plasticity related to changes in prey type and/or the way it is processed. What changes can we expect in tooth number, position, size and shape in relation to a changing function? Studies on dental variation have largely concentrated on mammals (cf. Miles and Grigson, 1990). [ABSTRACT FROM AUTHOR]

Introduction The past decade has seen remarkable advances in our understanding of the genetic control of embryonic development. We now know that developmental processes are initiated and controlled by interacting pathways of extracellular signalling molecules, receptors, intracellular signalling proteins and nuclear (transcription) factors. The different types of proteins (genes) that carry out these functions most often occur as members of families of related proteins characterised by possessing conserved amino acid motifs but which do not necessarily have similar functions in development. Thus for example, the transforming growth factor-beta (TGFβ) superfamily of secreted signalling proteins consists of a large family of proteins that share some homology with TGFβ, and in many cases share cell surface receptors (Kingsley, 1994). However, within this family different members have very different and specific functions in development. The bone morphogenetic protein Bmp-4, for example, probably has multiple functions as a signalling molecule in embryogenesis, including a role in lung morphogenesis, but targeted mutation of Bmp-4 (gene knock-out) shows a requirement for this protein for early mesoderm formation (Winnier et al., 1995; Bellusci et al., 1996). Bmp-7 on the other hand appears to have no direct role in mesoderm formation but is required for skeletal development (Luo et al., 1995). This illustrates a recurring theme in development where similar molecules have multiple functions, some of which overlap with other family members whereas others are unique. This almost certainly reflects the evolution of these gene families by gene duplication resulting in some shared and some unique functions. The First of these families of developmental genes to be discovered and the one which has produced the greatest interest is that of the homeobox genes. [ABSTRACT FROM AUTHOR]