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: 10 intact freshly extracted human teeth were prepared and divided into 2 groups, Group 1: S.s (1a: S.s without cementum, 1b: S.s with intact cementum) and Group 2:A.a (2a:A.a without cementum, 2b: 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 15days at 37˚C. The specimens were sectioned, mounted, stained with a fluorescent dye and viewed under the Confocal Scanning Electron Microscope at 40X 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. Keywords: bacterial invasion, confocal scanning electron microscope, cementum, radicular dentin
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: 10 intact freshly extracted human teeth were prepared and divided into 2 groups, Group 1: S.s (1a: S.s without cementum, 1b: S.s with intact cementum) and Group 2:A.a (2a:A.a without cementum, 2b: 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 15days at 37˚C. The specimens were sectioned, mounted, stained with a fluorescent dye and viewed under the Confocal Scanning Electron Microscope at 40X 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. Keywords: bacterial invasion, confocal scanning electron microscope, cementum, radicular dentin