Evaluation of push-out bond strength of different adhesive system applications

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F ibre-reinforced polymer posts have been employed to restore endodontically treated teeth that have suffered considerable loss of coronal structure since 1990s.[1,2] They offer a number of advantages over custom-fabricated cast alloy posts and core or prefabricated alloy posts.Fibre posts more closely match the modulus of elasticity of sound root dentin, thus distributing occlusal stresses more evenly in the root dentin and providing higher fracture resistance to weakened roots.[3,4] Other attractive features of fibre posts include resistance to corrosion, aesthetic appeal, and nonhypersensitivity. [5] Selecting an appropriate adhesive and luting procedure for bonding posts to root dentine is challenging.Various luting agents and corresponding adhesive systems have been proposed for bonding fiber posts to root canal dentin.These materials can be divided into self-etching adhesives and etch & rinse systems.[6] Results on the effectiveness of self-etching adhesive systems when compared with etch & rinses are contradictory.[7,8] Some studies show similarities between these systems [8,9] whilst others suggest a superiority of the etch & rinse materials.[7,10] In a confocal laser scanning microscopy study, the application Objective: To compare interfacial strength and failure modes of glass-fibre endodontic posts luted with three different adhesive luting agents.Methods: A total of 30 extracted human maxillary incisors were randomly divided in three groups and restored using glass-fibre posts and the following luting agents: an experimental self-etching primer/ resin-cement MSM-107 (EXP), ExciTE® F DSC adhesive/Variolink II (VII), Gradia Core self-etching bond/ Gradia Core cement (GC).Five sections of 1.00±0.05mm thickness were prepared from each specimen, and the post in each section was subjected to a push-out test.Failure modes of root slices after push-out testing were examined with stereomicroscope.The level of significance was set at alpha=0.05.Results: EXP achieved the highest bond strength.The mean value recorded for GC was significantly lower than EXP (p<0.05) and did not differ from VII (p>0.05).There was also no significant difference between EXP and VII (p>0.05).Bond failure was mainly mixed failure for VII and GC.Adhesive failures between the cement and the post, cohesive failures within the post and the dentin were mostly observed in EXP. Conclusion:The new experimental resin cement, MSM-107 showed promising results in term of bonding ability and might be used efficiently to restore endodontically treated teeth.