Einfluss verschiedener medikamentöser Einlagen auf den Haftverbund von GuttaFlow 2 zum Wurzelkanaldentin

2 Summary 2.1 Aim Intracanal medication is used routinely in endodontic treatment, either because there is not enough time in the practice or because it is needed for further disinfection of the root canal. There are numerous different products and pharmaceutical forms on the market. However chlorhexidine digluconate, calciumhydroxide or a combination of both agents are the most popular intracanal dressings. These products could not only have a positive disinfecting effect on the root canal, but could also have a negative effect on the bonding strength between the sealer and root canal dentin. Within this study the effect of calciumhydroxide and chlorhexidine digluconate, as a paste or as a inpregnated gutta-percha point, on the bonding strengh between GuttaFlow 2 and the root canal dentine should be determined. 2.2 Methods Sixty single rooted teeth with a straight root canal were instrumented with BioRaCe instruments (FKG Dentaire) until ISO 60 and were trimmed to a root canal length of 8 mm (resulting in a root canal surface of 17,2 mm2). Consecutively the sambles were randomly split into six groups (n=10): (A) Chlorhexamed-Gel 1% (GlaxoSmithKline), (B) UltraCal XS (Ultradent Corp.), (C) Activ Point (Coltène Whaledent), (D) Calciumhydroxide Plus Point (Coltène Whaledent), (E) dry root canal/no medication, (F) moist root canal/no medication. The intrcanal dressings remained in the canals for two weeks. The removeal of the medication was fristly done by a lavage of 2,5 ml Aqua dest. following by a passiv ultrasonic activated irigation for 60 s each with 2,5 ml NaOCl 2,5% und 2,5 ml EDTA 16% (EndoActivator, Dentsply Tulsa) and lastly a lavage with 2,5 ml NaOCl 2,5 % and 2,5 ml Aqua dest. without beeing activated. Spreaders ISO 25 (Dentsply Maillefer) were shortend apically and adjusted to the final size of ISO 60, though not silicated. Therafter the root canals were filled with GuttaFlow 2 und the spreader. After two weeks storage the bond strengths were analysed via Pullout mode by Ebert et al. (2011) using a Zwick universal testing mashine (Zwick-Roell). 2.3 Results GuttaFlow 2 showed very low bond strengths independent of the influencing factor, not achieving any differences concerning the bonding strengths in the comparison of the examined dressings (group/mean): (A) 0,8 MPa, (B) 0,8 MPa, (C) 0,6 MPa, (D) 0,6 MPa, (E) 0,6 MPa, (F) 0,5 MPa. Moisture in the root canal led to the lowest bond strengths and the insertion of chlorhexidine digluconate as a gel to highest in this study. However the bond strengths were not significantly different after the insertion of the various dressings. (Kruskal-Wallis-Test; p=0,259). 2.4 Conclusions The insertion of intracanal medication as an impregnated point does not effect the bonding strength of GuttaFlow 2 to the root canal dentin. The application of a dressing as a paste tends to result in an increase of the bonding strength. When using GuttaFlow 2 as an obstruction material the root canal should be dried thoroughly.