Bacterial invasion of dentinal tubules from the external root surface with and without an intact cemental layer- a confocal laser scanning microscopic study

Abstract

Aim To evaluate the invasion of two bacterial species Streptococcus sanguinis S s and Aggregatibacter actinomycetemcomitans A a in radicular dentinal tubules with and without an intact cemental layer using confocal laser scanning microscopy Methodology intact freshly extracted human teeth were prepared and divided into groups Group S s a S s without cementum b S s with intact cementum and Group A a a A a without cementum b with intact cementum The cemental layer on each root was removed from one side and kept intact on the other side The specimens were incubated in the bacterial suspension for days at C The specimens were sectioned mounted stained with a fluorescent dye and viewed under the Confocal Scanning Electron Microscope at X magnification The penetration of bacteria and presence of live bacteria in dentinal tubules in all the groups was analyzed Results In both the groups there was a significantly higher penetration of bacteria through the exposed dentin as compared to sections with intact cementum However there was a significantly higher penetration of Streptococcus sanguinis as compared to Aggregatibacter actinomycetemcomitans Conclusion An intact cemental layer protects the dentin from invasion of bacterial species These bacteria can lead to reinfection of treated periodontal pockets pulpal inflammation or persistence of periapical infections Therefore management of endodontic periodontic lesions and periodontal therapies should aim at preserving or regenerating a healthy cemental layer