INFLUENCE OF TOOTH INSTRUMENTATION ROUGHNESS ON SUBGINGIVAL MICROBIALCOLONIZATION

THIS STUDY EVALUATED MICROBIAL COLONIZATION OF periodontal pockets sub jected to root instrumentation with a curet or a rotating diamond. Ten maxillary and 10 mandibular subgingival pockets were established in t he canines of 5 beagle dogs. The subgingival root surface areas were d ebrided by a sharp curet or a flame-shaped, fine-grained, rotating dia mond point. The dogs were fed a plaque-inducing diet for 70 days. Spec imens from both instrumentation groups were then harvested and prepare d for stereomicroscopic and scanning electron microscopic evaluation. Grading of the extent of subgingival colonization was performed in cod ed specimens directly on the fluorescent screen of the scanning electr on microscope in a grid-counting system. Error of the method was asses sed by duplicate counts. The subgingival root surface areas were divid ed into 3 zones: cervical, middle, and apical, and statistical differe nces between these zones as well as between the 2 instrumentation grou ps were calculated. The results revealed that curet-treated surfaces w ere smoother and promoted less subgingival colonization than diamond-t reated surfaces. The difference in amount of bacterial colonization be tween the 2 groups was statistically significant (P <0.05) in all zone s. Bacterial colonization decreased in apical direction in both instru mentation groups. For the diamond-treated specimens, this decrease was significant (P <0.05) between each of the 3 zones. In the curet-treat ed specimens, the decrease was significant only between the cervical a nd the apical zone (P <0.05). The present study has demonstrated that subgingival instrumentation roughness significantly influences the sub gingival microbial colonization.