Radiographic examination of apical extrusion of root canal irrigants during cavitation induced by Er,Cr:YSGG laser irradiation: An in vivo study

Objectives: The purpose of the present study was to test the hypothesis that apical extrusion of the irrigant occurs during laser-driven irrigation in vivo. Materials and methods: Three hundred human root canals, in 181 patients, were divided into two groups: the no lesion group (n = 140) and the lesion group (n = 160). All the root canals were enlarged using a crown down technique up to size 30-80 K-files, depending on the original condition of the root canal. For the final irrigation, the teeth were irrigated with a mixture of radiopaque contrast medium and NaOCl in solution. The solution was activated for 60 s in teeth with one canal or two canals and for 120 s in teeth with three or four canals. Results: Radiopaque contrast medium was absent from the periapical tissues of all samples. Conclusions: No contrast medium was observed radiographically in the periapical tissues. The hypothesis that apical extrusion of root canal irrigants occur during laser cavitation was rejected Clinical relevance: It appears that the power of the laser used at 1 W for 1-2 min can drive the irrigation solution to the tip of the canal without harming the apical tissues.