Reduction of intracanal bacteria using GT rotary instrumentation, 5.25% Na0Cl, EDTA, and Ca(OH)2

This study was conducted to determine the bacterial reduction using Profile GT (R) files and a strict irrigation protocol utilizing 5.25% NaOCI and EDTA. The additive antibacterial effect of Ca(OH)(2) was also evaluated. In addition, the study compared the bacterial reduction with the GT protocol versus larger instrumentation. Thirty-one subjects with apical periodontitis were recruited. Bacterial samples were taken upon access (S1), after instrumentation and a strict irrigation protocol (S2), and following > 1 wk of Ca(OH)(2) (SC). A log(10) transformation of colony forming units was done since sample bacterial counts are not normally distributed. At S1, 93.55% of canals sampled bacteria. At S2, 52.72% of the cases sampled bacteria. At SC, 14% of the cases cultured bacteria. The McNemar test showed a significant reduction (p < 0.0009) in bacteria between S1 and S2. This was also true between S2 and SC (p < 0.0019). It was concluded the GT protocol significantly reduced the number of bacteria in the canal but failed to render the canal bacteria free in more than half of the cases Ca(OH)(2) application significantly further reduced bacteria. Lastly, large apical instrumentation removed more bacteria than small apical instrumentation.