Einfluss verschiedener Spülflüssigkeiten auf den Haftverbund von AH 26 zum Wurzelkanaldentin

SUMMARY Introduction In dentistry endodontic treatment plays an important role. Teeth with large destructions or a devitalized pulp may be preserved. The main goal consists in eliminating microorganisms and necrotic tissue and enlargement of the root canal in order to receive an adequate seal or an additional post preparation and core build-up. Sometimes posts are used to stabilize the tooth and to fix later restorations. The root canal system is a very complex system and may reveal accessorial canals which are responsible for reinfections due to microorganisms or remnants of tissue. The knowledge of the effect of the different endodontic irrigations on root canal dentine is of enormous importance to ensure a clean and sterilized dentine wall and to detect which effect they have on the bond strength of the sealer. Furthermore it is dicussed which role the smear layer generated on the basis of endodontically treatment plays and whether it should be leaved in its place or be removed. Aim of this study was to evaluate the influence of different irrigation solutions on the bond strength of AH 26 and the root canal dentine. Material and Methods For this study 60 humane teeth with one root and a straight canal profile were selected. Each tooth was previously not endodontically treated and did not show large destructions. After decoronation the prepared teeth were mechanically instrumented with BioRaCe (FKG Dentaire) to enlarge the root canal up to ISO 60 and 8 mm. Then the specimens were randomly divided into five groups (n=12). group I: EDTA 17 % group II: chlorhexidine gluconate 2 % group III: sodium hypochlorite 3 % group IV: citric acid 40 % group V: distilled water (controll group) Each group was irrigated with 5 ml of the specific solution for 3 minutes. After drying the root canal with paper points AH 26 was applied with the help of a lentulo and standardized spreaders of size ISO 60 were inserted up to the working length of 8 mm. The fitting was inspected and the teeth were stored for two weeks at 37 °C. Afterwards the specimens were subjected to a pullout-test (Ebert et al., 2011) using Zwick universal testing machine 1120 (Zwick-Roell) to find out the maximal bond strength of the sealer to the root canal dentine. To interpretate the results SPSS 21 (IBM) including Kruskal-Wallis and Mann-Whitney test were utilized. Fracture modes (adhesive, cohesive or mixed) were determined using microphotographs of the extruded spreaders of two aspects. Results Rinsing the root canal with dístilled water resulted in the highest bond strength values (5,77 MPa) of the sealer in the present study. In contrast to that citric acid showed a median of 0,82 MPa compared with all other groups, revealing the significantly lowest bond strength values. When irrigating the root canal with NaOCl bond strength of AH 26 was significantly lower than using distilled water. By analysing the fractures modes of the spreaders there were almost observed mixed qualities. Conclusion On examination the bond strength after rinsing the root canal with different endodontic irrigation solutions there are various results. Citric acid showed the lowest bond strength potentially caused by increased demineralisation that is inadequate for obtaining ideal bond strength of AH 26 demineralize the root dentine too hard due to its strong acidic potential.