THE EPITHELIAL ATTACHMENT AND THE DENTAL JUNCTIONAL EPITHELIUM - ULTRASTRUCTURAL FEATURES IN PORCINE MOLARS

The region of epithelial apposition with a tooth surface is the site o f an unusual stratified integument, the junctional epithelium, which c ombines tight attachment to the tooth, cell turnover, tissue permeabil ity, and epithelial versatility into the first line of defense against periodontal destruction by oral pathogens. To better understand the s tructure and;function of the junctional epithelium we have reviewed it s developmental and cell biology, and undertaken a multidisciplinary a nalysis of its composition in the pig, an omnivore whose dietary and d ental development and occlusion patterns are similar to the human cond ition, and which, because of its size, is more readily amenable to exp erimental manipulation. The porcine junctional epithelium was also com pared with this well-described epithelium in the rat. Morphological an alyses by light microscopy and scanning and transmission electron micr oscopy showed the porcine junctional epithelium and epithelial attachm ent were similar to that in the rat except that apically, extracellula r matrix lamellae associated with the internal basal lamina were more complex, and more coronally there was extensive layering of a dental c uticle-like material. Biochemical analysis of the porcine junctional e pithelium by dissociative extraction and SDS-PAGE revealed the presenc e of some proteins not present in gingival epithelium. Together, these studies show that the porcine junctional epithelium has predictable m orphological and biochemical features which establish the pig as an ad vantageous model to study the basic and clinical biology of this uniqu e epithelium. (C) 1994 Wiley-Liss, Inc.