Ultrastructural location of Streptococcus mutans and Streptococcus sanguis antigens in carious human dentine.

The ultrastructural localization of bacterial antigens of Streptococcus sanguis and of the various serotypes a,b,c,d,e,f and g of Streptococcus mutans was studied in human carious dentine using the indirect peroxidase-antiperoxidase method with appropriate controls. No positive staining was seen in adjacent normal dentine. In the inner dentine underlying the cytoplasm of fibroblasts and Schwann cells of unmyelinated nerve fibrils. In sclerosed tubules, or on the plasmalemma of the odontoblast process or on both structures. Only in the odontoblast, facing the carious cone, were dense stainings noted in vacuoles of various sizes located in the Golgi apparatus in juxta-nuclear position and in their odontoblast processes. In pulpal regions, underlying the carious cone, dense vacuoles were also observed in the cytoplasm of fibroblasts and Schwann cells of unmyelinated nerve fibrils. In sclerosed tubules, electron dense deposits were noted in the lumen and the walls of the calcified tubules. In the outer carious dentine, invaded by micro-organisms, positive antigenic stainings were observed in the cell wall and capsular material of a great number of micro-organisms as well as in the interbacterial matrix.