The Influence Of The Root Canal Internal Surface Treatment To Bond Strength Of Fiber Post To Root Canal

Because of their excellent physical and chemical properties, fiber posts have been a growing number of applications. How to improve the bond strength of fiber post has become a hot research. In order to obtain a better bonding strength, we do some appropriate treatment on tooth hard tissue. The preparation of root canal wall dentin surface is one of important factors to influence the bond strength of fiber posts. In this study, we hope to find a method of treatment on the dentin of root canal wall to improve the bonding strength of fiber posts. It can provide a theoretical basis for Clinical applications.The purpose of this study was to evaluate the effect of surface treatment on the retention of glass fiber posts luted with resin cement Solution of chlorhexidine is widely used in root canal irrigation and degermation, and it's also a broad-spectrum anti-bacterial agent. It can be absorbed by dentinal tubules, and then kills the bacteria directly. It has a better role in killing of both aerobic and anaerobic bacteria. As an irrigation agent, 2%Chlorhexidine is more effective agent against anaerobic bacteria than 5.25% sodium hypochlorite in infected root canals, but it is less toxic and corrosive. 2%Chlorhexidine can also get rid of the restriction of the application of rubber dam. The value of the popularization and application of 2%Chlorhexidine is obviously in the condition of rubber dam has not been universal in our country. Up to now, there were little reports of Chlorhexidine solution apply in preparation of root canal.In this experiment, we collected 20 new extracted non-caries single root canal anterior, Post spaces were prepared in Extracted teeth and then the root canals were subjected to one of the following post-space treatments: (i)water irrigation(control); (ii) irrigation with 3% hydrogen peroxide followed by 5.25%sodium hypochlorite(NaOCl); (iii) irrigation with 2%chlorhexidine solution followed by 5.25%sodium hypochlorite(NaOCl); (iv) irrigation with 2%chlorhexidine solution followed by 17%EDTA solution; (v) irrigation with 3% hydrogen peroxide followed by 17%EDTA solution; (vi) irrigation with 5.25%sodium hypochlorite (NaOCl) followed by 17%EDTA solution; (vii) etching with 35% phosphoric acid-gel for 30s; (viii) 17%EDTA-gel for 1min.The dentin surface s were examined under scanning electron microscopy (SEM) after different post-space treatments. According to the result of scanning electron microscopy examination, we selected six experimental groups of them for next step and observation. Fiber posts were then luted in the treated roots using resin cement with and the thin-slice push-out test was performed. Scanning electron microscopy showed that not all the post-space treatments tested were effective in removal of the smear layer of debris, or sealer / gutta-percharemnants, on the root canal. Group (iv) (v) (vi) (vii) and (viii) were effective. The apical push-out strength was affected by post-space treatment. Both 35%phosphoric acid-gel etching and irrigation with 2%chlorhexidine solution followed by 17%EDTA solution improved the apical push-out strength of the fiber post, with self-etching system. The depth of post space has no influence of apical push-out strength.The result of Chi-square test shows that, there is conspicuous difference. Specimen of the experimental group between the fracture mode was significant difference (p <0.05).The damage of posts did not observed in this experiment.Resin rags of dentin bonding interface were observed in group (iv)and group(vii) by FE-SEM.In order to improve the bonding strength of fiber posts,we did some different treatments of post-space surface in this study,it provids a theoretical basis for clinical applications.