Microleakage-Untersuchung von Wurzelkanalfüllungen nach unterschiedlichen Abschlussspülungen: drei klassische Wurzelkanalsealer im Vergleich

Objectives The chemical cleaning and disinfection of the root canal system is performed by endo-dontic irrigations. A complete drying of the root canals and its numerous ramifications technically not achievable so that residues of the rinsing solutions remain within the endodontic system. The large number of upcoming new root canal sealers in combina-tion with the currently used irrigation solutions raises the question to what extent the residual moisture from the branched root canal system influences the setting properties of the sealers, thus affecting the seal of the root filling. The aim of the study was to find out which sealer and irrigation combination revealed the most positive effect on the apical seal of the root filling. Materials and Methods 150 human extracted teeth with straight canals according to Schneider class I were divided in three experimental groups and subdivided into five groups of 10 teeth and one control group. After preparation of access cavities, the samples were instrumented by ProFile .04/#45. Sodium hypochlorite (5%) and citric acid (40%) were used as irrigants. After recontamination of the root canal with the subgroup defining lavages, EDTA (15%), sodium ascorbate (10%), CHX (2%) or water and schematic excess distance, the respective sealer was mixed according to manufacturer's recommendation and placed with a lentulo spiral into the root canals and the obturation performed by a single cone technique. One group was used as control and canals were completely dried. The sealer was allowed to set for 7 days in a wet chamber (37°C/100% humidity). After the teeth were sealed with two layers of nail polish the root tips were removed until the gutta-percha filling appeared apically. Then, a dye penetration test was performed using 5% methylene blue solution. Serial cutting of the specimen allowed the assessment of dye penetration under a light microscope (30x magnification). Results The study shows that the different irrigations affected the sealing efficiency of the in-vestigated sealers differently. The highest leakage occurred with Tubli-Seal. Especially the final rinse with ascorbate and CHX did not show sufficient sealing efficiency. Be-tween AH Plus and Apexit there were no significant differences detected. The sealer Apexit revealed the lowest leakage values with all irrigation solutions. The highest leakage occurred in the presence of CHX contamination. All three sealers showed ra-ther poor results here, but only Tubli-Seal in combination with sodium ascorbate demonstrated even worse results and thus, the worst of all combinations in the present study. EDTA revealed the least impact on the sealing efficiency of all sealers investi-gated. Conclusion A substantial drying of the canal system is still highly important, as both the classic and more recent sealer can be very sensitive to moisture. The contamination with a liquid may not generally have a negative impact on the sealing efficiency, but more the nature of the liquid. In particular, regarding the use of different root canal irrigations it is important to know how far the used irrigations affect the sealing properties of the seal-er. Not every sealer revealed similar sealing efficiency with the different root canal irri-gants.