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Comparative bactericidal exposures for selected oral bacteria using carbon dioxide laser radiation.
D N Dederich1, M A Pickard, A S Vaughn
1Division of Biomaterials, Faculty of Dentistry, University of Alberta, Edmonton, Canada.
Lasers in Surgery and Medicine
|January 1, 1990
Summary
This study found that lower carbon dioxide (CO2) laser energy densities, under 200 J/cm2, can effectively kill over 99.5% of bacteria. This is significantly less energy than previously thought necessary for sterilization.
Area of Science:
- Dentistry
- Microbiology
- Biophysics
Background:
- High CO2 laser energies have been previously demonstrated for root canal sterilization.
- The precise energy thresholds for bacterial inactivation by CO2 lasers at varying exposures are not fully understood.
Purpose of the Study:
- To investigate the bacterial response to decreasing exposures of CO2 laser energy.
- To determine the minimum energy density required for significant bacterial inactivation.
Main Methods:
- Bacterial strains were cultured and irradiated on glass microscope coverslips.
- Bacterial viability was assessed after exposure to varying CO2 laser energy densities.
- Comparisons were made between equivalent energy exposures using differing laser parameters.
Main Results:
- No significant difference in energy was required to kill closely related bacterial species.
- An energy density below 200 J/cm2 was sufficient to eliminate >99.5% of bacteria.
- This effective energy density is substantially lower than previously reported sterilization levels.
Conclusions:
- CO2 laser sterilization of bacteria can be achieved at lower energy densities than previously established.
- The findings suggest potential for more conservative CO2 laser applications in procedures like root canal sterilization.