Shear bond strength of endodontic sealers to dentin with and without smear layer and gutta percha (An in vitro study)


Background: The bond strength of root canal sealers to dentin and gutta-percha seems to be an important propertyfor maintaining the stability of root canal filling, which potentially influences both leakage and root strength. Theobjective of this, in vitro, study was to evaluate the shear bond strength of three different endodontic sealers (Gutta-Flow, AH Plus, Apexit Plus) to dentin, in the presence and absence of the smear layer and gutta percha.Material and Methods: After slicing off the occlusal 2mm of 60 extracted human maxillary premolar teeth, theexposed dentin served as the tested surfaces; the teeth were fixed with cold cure acrylic, and were divided into twogroups according to the smear layer presence, group A without smear layer, when dentin surfaces were irrigatedwith EDTA 17% followed by distilled water then subdivided into 3 subgroups according to the type of sealer used;group B when dentin surfaces were washed with distilled water only, then subdivided into 3 subgroups. Thirty samplesof gutta-percha were prepared and named as group C which was subdivided into 3 subgroups. Five mm longsection of polyethylene tubes were placed on the dentin or gutta percha surfaces and filled with freshly mixedsealer. After one week, all the samples were tested for shear bond strength by the Instron Universal Testing Machineat a cross head speed of 0.5 mm/min. The data was calculated in MPa and was statistically analyzedResult: There was a highly significant difference in the shear bond strength (P < 0.05) in comparison among the testedgroups, GuttaFlow showed non-significant difference in bond strength to dentin with and without smear layer, whileAH Plus and Apexit Plus showed a high significant difference.Conclusions: AHPlus showed the highest shear bond strength in all the tested samples, while GuttaFlow was the least.Additionally, AH Plus and Apexit Plus shear bond strengths were affected by the smear layer removal, whileGuttaFlow was not.