REGIONAL VARIATION IN ROOT DENTINAL TUBULE INFECTION BY STREPTOCOCCUS-GORDONII

The purpose of this study was to investigate the pattern of bacterial invasion of dentinal tubules at different regions in human roots. Spec imens were obtained from single-rooted teeth that had their root canal s prepared in a standard manner, Roots were then sectioned longitudina lly through the canals and the resulting specimens chemically treated to remove the smear layers, Specimens were immersed in a suspension of Streptococcus gordonii for 3 weeks and then prepared for histological analysis, Sections from the cervical, midroot, and apical areas were examined, The pattern of bacterial infection of the cervical and midro ot areas was similar, characterized as a heavy infection with bacteria penetrating as deep as 200 mu m. Invasion of the apical dentin was si gnificantly different, with a mild infection and maximum penetration o f 60 mu m.