Influence of different irrigation techniques on sealer penetration into dentinal tubules: a confocal laser scanning microscope analysis

BACKGROUND: The instrumentation of roots canals pro- duces smear layer, which consists of organic and inorganic material and may also contain bacteria and they by-products. This layer covers the root canal walls, could obliterate den- tinal tubules and consequently can inhibit the penetration of irrigants and endodontic sealers. To obtain a good seal is necessary to use an endodontic sealer in association with a core filling material in order to fill any voids, morphological irregularities, apical deltas and dentinal tubules and to create an obturation as much as possible impervious. The aim of the study was to compare the effect of conventional endodontic needle irrigation and different irrigation systems on sealer penetration into dentinal tubules. METHODS: 40 single round root canals were selected and divided into four groups (n=10) before root canal preparation according to the final irrigation protocol: group 1 (conventional endodontic needle irrigation), group 2 (EndoActivator) group 3 (Irrisafe) group 4 (EndoVac). The root canal were shaped using Path File and ProTaper Universal rotary system in a crown-down sequence to size #40 at the WL. Obturation of the teeth was done with Thermafil Obturators size 40 with TopSeal sealer labeled with 0,1% wt Rhodamin B dye. Transverse sec- tion at 2-, 5- and 7-mm from the apex were analyzed by means of confocal laser scanning microscopy. Percentage of pen- etration around the root canal and the mean penetration into dentinal tubules at eight standardized points were calculated. RESULTS: No significant differences in percentage of pen- etration around the root canal and mean penetration depth into dentinal tubules were observed among groups when same levels were compared. Within each group both variables are significantly higher at the coronal and middle level with respect to the apical one. CONCLUSIONS: The use of the techniques employed in the present study did not significantly improve the sealer pen- etration into dentinal tubules compared with conventional endodontic needle irrigation.