Evaluation of bacterial kill in human roots infected with Enterococcus faecalis biofilm following 980 nm laser activation of chlorhexidine

Effectiveness of root canal disinfection greatly determines the success of endodontic treatment. The purpose of this study was to evaluate the bacterial killing efficacy of chlorhexidine (CHX) activated with a Gemni 980 nm diode laser. Bacterial kill at the apical one third of the endodontically prepared roots were assessed using the 3D fluorescent microscope (SZX16) after staining the tooth with BacLight SYTO 9 (Live/Dead). The percentage of bacterial kill was calculated by measuring the total amount of green pixels (live bacteria) and red pixels (dead bacteria) using the Image color summarizer image color statistics and clustering program (Circos—Circular Genome Visualization/Martin Krzywinski). The 3D fluorescent ex‐vivo tooth model allowed real time measurement of the percentage of bacterial kill at specified time points by capturing the bacterial kill on the external surface of the root, hence indicating the amount of penetration of the irrigation solution through the radicular dentine. Compared to CHX alone, both Endoactivator and diode laser treatment groups showed significantly better bacterial kill following a 72‐hour study period ( P  > .05). However, of clinical importance is the larger number of bacteria killed with laser assisted irrigation immediately following treatment when compared to the use of CHX alone.