J.J. Pindborg – författare

Inter-relationships of the Dental Tissues The tooth germ has three main components -the enamel organ, the dental papilla and the dental follicle (Fig. 1). The enamel organ is an epithelial structure derived from the ectoderm that lines much of the oral cavity. The dental papilla and the dental follicle are ectomesen­ chymal (mesectodermal), being partly derived from cells that mi­ grated from the neural crest early in embryogenesis. Both the gross morphology of the tooth germ and the differentiation of its cells de­ pend upon a complex pattern of inductive interactions between the epithelium and the ectomesenchyme. The sites in which the teeth will form appear to be determined before the commencement of epithelial downgrowth from the oral epithelium to form the odontogenic epithelium. This epithelial downgrowth (the dental lamina ), the development of the enamel or­ gans of the individual teeth, and the morphology of each enamel organ, are controlled by the ectomesenchyme. The enamel organ is responsible for the formation of enamel and comprises four layers: outer dental epithelium, stellate reticulum, stratum intermedium and inner dental epithelium (Figs. 1 and 2a).

There are two major differences in concept between this volume and others in the International Histological Classification of Tu­ mours series. The first of these is the inclusion of more clinical aspects than has usually been the case and the second is a con­ centration on a more limited range of conditions. There are sev­ eral reasons for adopting this approach. With regard to both cancer and pre cancer of the oral mucosa, we believe it is impor­ tant that general pathologists, in whose interests this volume has primarily been written, should be informed of the significance of the clinical features of the various lesions under discussion as they may on the whole be unfamiliar with them. Also, we con­ sider it necessary to draw attention to those conditions particu­ lar to the oral tissues that may give rise to appearances which are important in differential diagnosis but can be misleading to the pathologist who does not have detailed knowledge of these tissues. On the other hand, many of the benign and malignant tumours that affect the oral tissues have been dealt with in other volumes in the series and we believe that little or no advantage would be gained by repeating them here.

There are two major differences in concept between this volume and others in the International Histological Classification of Tu­ mours series. The first of these is the inclusion of more clinical aspects than has usually been the case and the second is a con­ centration on a more limited range of conditions. There are sev­ eral reasons for adopting this approach. With regard to both cancer and pre cancer of the oral mucosa, we believe it is impor­ tant that general pathologists, in whose interests this volume has primarily been written, should be informed of the significance of the clinical features of the various lesions under discussion as they may on the whole be unfamiliar with them. Also, we con­ sider it necessary to draw attention to those conditions particu­ lar to the oral tissues that may give rise to appearances which are important in differential diagnosis but can be misleading to the pathologist who does not have detailed knowledge of these tissues. On the other hand, many of the benign and malignant tumours that affect the oral tissues have been dealt with in other volumes in the series and we believe that little or no advantage would be gained by repeating them here.