The Effect Of Different Root Canal Internal Surface Treatment On Bond Strength Of Quartz Fiber Post

ObjectiveTo investigate the effect of different pretreatments to root canal dentin on micro push-out strength of quartz fiber post to dentin after Post space preparation. And to evaluate the bond strength of different regions of the root. So that appropriate pretreatments to root canal dentin can be used for clinical selection and providing a theoretical basis for improvement bond strength of resin cement to root canal dentin.Methodtwenty-four bicuspid teeth with single root were collected after extraction and saved in negative twenty degree Celsius physiological saline. One week after endodontical treatment, the post space preparation of all teeth were made, the teeth were assigned into four groups randomly with 8 teeth each. The teeth of four groups were irrigated with distilled water, EDTA gel, 1%NaClO and EDTA gel+l%NaClO for 60s respectively.2 teeth were obtained from each group and splitted into two pieces. Observed the middle sections' microscopic characteristic of the root canal dentin surface with SEM. Panavia F self-etching resin bonding cement was imported into other teeth's post space according to the instructions. After cementation, the roots were subjected to simulated aging conditions as thermal cycles. The roots were sectioned into slices with 1mm thickness and a micro push-out test was performed on three different sections of each root to measure bond strengths. Test piece following testing was placed under optical microscope to observe the breakage method.Results1. Both EDTA gel and 1%NaClO notably improved the micro push-out strength (P<0.05).But no significant difference in bond strength was determined between EDTA gel and 1%NaClO groups(P>0.05).2. no significant difference in bond strength was determined between EDTA gel+1%NaClO groups and the control group.(P>0.05)3. The coronal third of the root resulted in statistically greater bond strengths than the medium third, whose bond strength was significantly greater than the apical third(P<0.05)Conclusion1.EDTA gel and 1% NaCIO irrigation to post space before bonding could enhance the bonding strength between resin cement and dentin2.1%NaClO followed by EDTA gel irrigation to post space before bonding could not enhance the bonding strength between resin cement and dentin3.Bonding was more predictable at the coronal level of the root.