Bactericidal effect of KTP laser irradiation against Enterococcus faecalis compared with gaseous ozone: an ex vivo study

Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 May;107(5):e73-9. doi: 10.1016/j.tripleo.2009.01.048.


Objective: The objective of this study was to evaluate the antimicrobial activity of potassium-titanyl-phosphate (KTP) laser and gaseous ozone in experimentally infected root canals.

Study design: Eighty single-rooted teeth with straight canals were selected. After preparation and sterilization, the specimens were inoculated with 10 microL Enterococcus faecalis for 24 hours at 37 degrees C. The contaminated roots were divided into 2 experimental groups, 1 negative control group, and 1 positive control group of 20 teeth each: Group 1, KTP laser group; Group 2, gaseous ozone group; Group 3, sodium hypochlorite group (NaOCl) (negative control); and Group 4, saline group (positive control). Sterile paper points used to sample bacteria from the root canals were transferred to tubes containing 5 mL of brain heart infusion broth. Then 10-microL suspension was inoculated onto blood agar plates. The colonies of bacteria were counted and data were analyzed statistically using Kruskal-Wallis 1-way analysis of variance and Mann-Whitney U tests.

Results: There were statistically significant differences between all groups (P < .05). The saline group had the highest number of remaining microorganisms. Complete sterilization was achieved in the 2.5% NaOCl group. The KTP laser and gaseous ozone did not completely sterilize the root canals.

Conclusion: Both KTP laser and gaseous ozone have a significant antibacterial effect on infected root canals, with the gaseous ozone being more effective than the KTP laser. However, 2.5% NaOCl was superior in its antimicrobial abilities compared with KTP laser and gaseous ozone.

Publication types

  • Evaluation Study

MeSH terms

  • Anti-Infective Agents, Local / pharmacology
  • Colony Count, Microbial
  • Dental Pulp Cavity / microbiology*
  • Dentin / microbiology
  • Dentin Permeability
  • Enterococcus faecalis / drug effects*
  • Enterococcus faecalis / radiation effects*
  • Humans
  • Lasers, Solid-State*
  • Ozone*
  • Phosphates
  • Root Canal Irrigants / pharmacology*
  • Sodium Hypochlorite / pharmacology
  • Titanium


  • Anti-Infective Agents, Local
  • Phosphates
  • Root Canal Irrigants
  • potassium titanylphosphate
  • Ozone
  • Titanium
  • Sodium Hypochlorite