The purpose of this study was to evaluate the effects of CO2 laser irradiation on penetration of constricted canals.
Root canals of human extracted teeth were opened by the usual method, and penetration of constricted canals to the apical foramen was performed with #15k-files.
Fifteen canals, including eight incisors and seven premolars that could not be penetrated, were selected as the constricted specimens (n=15).
These specimens were irradiated by a CO2 laser (E16, 9W, 0.5sec).
After the irradiation, penetration to the apical foramen with #15 k-files was attempted.
After the laser irradiation, the rate of penetration to the apical foramen was evaluated.
The root surface temperature was also measured by an infrared thermometer before, during, and after the irradiation.
Ten canals (67%) could be penetrated to the apical foramen.
The root surface temperature increased during the irradiation.
The CO2 laser irradiation could penetrate to the apical foramen; the mean rate of the penetration distance was 0.78±0.39mm (n=15).
This study suggested that CO2 laser irradiation can penetrate a constricted root canal to the apical foramen.
