Effects Of Radicular Dentin Treatments And Luting Materials On The Bond Of Quartz Fiber Posts In Vitro

PartΙEffects of Radicular Dentin Treatments and Luting Materials on the Bond Strength of Quartz Fiber Posts:Push-out TestObjective : To investigate the effects of radicular dentin treatments of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the regional root canal bond strengths of quartz fiber posts using 2 luting materials in vitro.Methods: 36 intact extracted maxillary central incisors were sectioned perpendicular to the long axis at a point of 2.00mm-occlusal to the buccal cement-enamel junction (CEJ) and then endodontically treated. All specimens were randomly divided into 6 groups (n=6). Following standardized post space preparations and acid etch, quartz fiber posts ( D.T.LIGHT-POST ) were placed using three radicular dentin treatments (0.9% NaCl for 60s, 10% NaOCl for 60s, 17% EDTA for 60s followed by 5.25% NaOCl for 60s)and two luting materials (ONE-STEP? / DuoLink, ONE-STEP? / LuxaCore) respectively(factorial design).8 Slices with a thickness of 1.00±0.05 mm were prepared from the coronal third of each root. The push-out test was performed on different sections of each roo(tS2,S4, S6)at a crosshead speed of 0.5 mm/min. The data were recorded and analyzed (a= 0.05).Results: A significant difference was found among the groups.10% NaOCl treatment groups showed higher push-out strengths than that of the control (p<0.0001). 17% EDTA followed by 5.25% NaOCl treatment groups showed higher push-out strengths than that of the control (p<0.0001). DuoLink groups resulted in higher strength than that of LuxaCore groups (p<0.0001). Bond strengths decreased significantly from coronal to apical root canal regions. Conclusion: Within the limitations of this study, micro push-out bond strengths of quartz fiber post can be affected by radicular dentin treatment and luting materials. 10% NaOCl treatment and resin cement combinations resulted in higher bond strength values.PartΙΙEffects of Radicular Dentin Treatment and Luting Materials on the Bond of Quartz Fiber Posts : SEM StudyObjective: To investigate the effects of radicular dentin treatments of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the regional root canal bonding interface of quartz fiber posts using 2 luting materials by SEM analysis.Methods: 36 intact extracted maxillary central incisors were sectioned perpendicular to the long axis at a point of 2.00mm-occlusal to the buccal cement-enamel junction (CEJ) and then endodontically treated. Following standardized post space preparations and acid etch , All specimens were randomly divided into 6 groups (n=6), quartz fiber posts ( D.T.LIGHT-POST ) were placed using three radicular dentin treatments (0.9% NaCl for 60s, 10% NaOCl for 60s, 17% EDTA for 60s followed by 5.25% NaOCl for 60s) and two luting materials (ONE-STEP? / DuoLink, ONE-STEP? / LuxaCore) respectively(factorial design). 8 Slices with a thickness of 1.00±0.05 mm were prepared from the coronal third of each root. Cervical,middle,apical sections (S1,S5,S7) of each root are used for SEM study and for spectroscopy of dispersion energy (EDS) microanalysis. And another 3 intact maxillary central incisors were selected to be prepared according to the procedure above-mentioned (sectioned,endodontically treated,post space prepared,acid etched, treated by the three radicular dentin treatments respectively), and then were sectioned longitudinally to be observed. Results: No typical hybrid layer was found while the effects of radicular dentin treatments on penetration of resin tags into the dentinal tubules were clearly observed at the resin-dentin interfaces.Conclusion: Radicular dentin treatments provided good resin infiltration, producing a three-dimensional interlocking micronetwork of resin tags in the dentin tubules with multiple lateral branches that penetrate the intertubular dentin, which positively influenced the adhesion between dentin and the two Luting Materials.