The histology of rat molar tooth fissure plaque

Abstract

Plaque from the central fissure of the lower first molar tooth fed Stephan 580 sucrose or glucose diet for 15 days consisted of a dense mass of microorganisms, predominantly Gram-positive cocci and short rods, together with impacted food. Plaque microorganisms contained intracellular polysaccharide, and sucrose plaque contained appreciable extracellular polysaccharide whereas glucose plaque contained little extracellular polysaccharide. Scanning electron microscopy revealed the absence of filamentous bacteria in the plaque. The development of plaque and caries was followed up to 5 days after feeding cariogenic diets. Fissure lesions were evident in most animals after 3 days, and dietary sucrose tended to promote the earlier initiation of more lesions than glucose. Plaque from weanling rats contained impacted wood and stock pellet residue. An increasing bacterial population was noted after feeding cariogenic rations, although lignified material remained evident after 5 days.