Decontamination efficacy of photon initiated photoacustic streaming (PIPS) of irrigants using low energy laser settings: an in vitro study

Introduction: To asses the antibacterial effectiveness of photon initiated photoacustic streaming (PIPS) of irrigants using an Er:YAG laser in infected root canals. Materials & Methods: One hundred-forty-eight single- rooted extracted teeth were prepared to a size #25.06 taper. After sterilization, all teeth except ten (negative control group) were inoculated with Enterococcus fàecalis. Infected teeth were then randomly divided into 4 test groups (n-32 for each) and 1 positive control group (n-10): pulsed erbium:yAG laser at non-ablative settings for 30 seconds with sterile bi-distilled water or 50% sodium hypochlorite (NaOCl) irrigation (Group A and B respectively); only sterile bi-distilled water or only 5% NaOCI irrigation for 30 seconds (Group C and D respectively); no treated infected teeth (positive control group). Colony-forming units (CFUs) were counted from bacteriologic samples taken before (S1) and after treatment (S2). Results: Group B showed the highest bacteria CFUs reduction that was significantly greater than that of group A and C (P0.05). None of the four groups predictably generated negative sampies, but NaOCI with PIPS activation was superior to the other three groups in this aspect. Conclusions: Er:Yag laser and PIPS technique along with the irrigants resulted highly effective in decontaminating the infected root canals and produced more negative samples than the other groups.