Efeito imediato do tratamento prévio com clorexidina na adesão de pinos de fibra com cimento resinoso autoadesivo

Abstract

The effect of chlorhexidine (CHX) on root dentin applied by different methods and its influence on the adhesion of fiberglass posts (GFP) cemented with self-adhesive resin cement was evaluated. A total of sixty uniradicular permanent teeth were used, which had their crowns removed and their roots treated endodontically. After one week, the standard preparation of the post space was made for the cementation of the GFP. At this time, the roots were randomly divided into five groups, according to the combination of the following factors: dentin treatment prior to cementation of GFP (irrigation solution + irrigation method) - NaOCl 2,5% with conventional needle irrigation (NaOCl-AG - control), CHX 2% with conventional needle irrigation (CHX-AG), CHX 2% with active ultrasonic irrigation (CHX-ULT), CHX 2% with active irrigation by Easy Clean (CHX-EC), and CHX 2% with active irrigation by XP-Endo Finisher (CHXXP). For each group two roots were selected and prepared for ultra-structural morphological evaluation of the smear layer (SL) by scanning electron microscopy (SEM). After the cementation procedures, seven roots per group were randomly evaluated in bond strength (BS) by push-out test and three for nanoleakage (NL). For the SL pattern, it can be observed that the CHX-AG group did not promote SL removal (score 3). The NaOCl-AG group and the groups in which CHX was actively applied (CHX-ULT, CHX-EC and CHX-XP) partially removed SL similarly (score 2). For BS, the two-way ANOVA test showed that the double interaction (dentin treatment vs root region) was significant (p <0.001). All groups presented significantly higher BS values in the coronal third compared to the middle and apical thirds (p <0.05), except for CHXAG. In the middle third, CHX-ULT and CHX-EC obtained BS results significantly higher than CHX-AG; however, they were statistically similar to NaOCl-AG and CHX-XP. For NL, the two-way ANOVA test showed that the double interaction (dentin treatment vs root region) was not significant (p = 0.193); only the main factors root region (p <0.001) and dentine treatment (p <0.001) were statistically significant. Regarding the root region, lower NL values were observed in the coronary third, and the highest values in the apical third. Regarding dentin treatments, the highest NL value was observed in the control group (NaOCl-AG), followed by CHX-AG. The lowest NL value was observed for CHX-ULT, which was statistically similar to CHX-XP. It can be concluded that the active application of chlorhexidine kept the BS results similar to the control group in all root regions, and it was possible to decrease the NI values when compared to the passive application of chlorhexidine and the control group.