In vitro irradiation of infected root canals with a diode laser: results of microbiologic, infrared spectrometric, and stain penetration examinations

Quintessence Int. 1997 Mar;28(3):205-9.


This study aimed to examine the suitability of the diode laser with a wavelength of 810 nm for reducing bacteria in root canals. Forty-four extracted, endodontically prepared teeth were inoculated with Escherichia coli and Streptococcus faecalis. No bacterial growth was observed when the teeth were irradiated at an output power of 4 W and a pulse rate of 10 milliseconds, with breaks of 10 milliseconds between the irradiations. Exposure time was five times 5 seconds. Infrared spectroscopic examinations revealed that irradiation at 4 W under even circling movements resulted in a maximum rise in temperature of 6 degrees C on the root surface. Stain penetration tests and scanning electron microscopic examinations revealed complete closure of the dentinal tubules on the irradiated root canal walls.

MeSH terms

  • Dental Pulp Cavity / microbiology
  • Dental Pulp Cavity / radiation effects*
  • Dentin / microbiology
  • Dentin / radiation effects
  • Disinfection / instrumentation
  • Disinfection / methods*
  • Dose-Response Relationship, Radiation
  • Enterococcus faecalis / radiation effects
  • Escherichia coli / radiation effects
  • Humans
  • In Vitro Techniques
  • Laser Therapy*
  • Microscopy, Electron, Scanning
  • Root Canal Preparation / instrumentation
  • Spectrophotometry, Infrared
  • Staining and Labeling