The apical border plaque in chronic adult periodontitis. An ultrastructural study. II. Adhesion, matrix, and carbohydrate metabolism.

THE AIM OF THIS STUDY was to characterize the plaque matrix and relevant aspects of metabolism of the apical border plaque in relation to teeth affected by chronic adult periodontitis. The material comprised 56 teeth from 24 patients. Ruthenium red, alcian blue, lanthanum nitrate, and safranin 0 were used to label matrix polyanionic macromolecules and periodic acid-thiosemicarbazide-silver proteinate for intracellular polysaccharide (IPS). The matrix components were amorphous, fibrillar, or globular. Many intact bacteria exhibited extracellular polysaccharides or glycocalyces associated with their cell wall and cytoplasmic IPS granules. The latter varied in size and distribution and were evident even in the most apically-advanced intact microorganisms. The results indicate that the matrix and IPS features of the apical border plaque in chronic periodontitis in certain respects resemble those of subcontact area plaque on children's teeth, associated with chronic gingivitis and approximal caries. They also suggest the establishment of acidic regions in the microniches of the periodontal pocket.