Abstract
The aim of this study was to compare in vitro the bond strength (BS) between fiberglass posts and flared root canals reinforced with different materials. The roots of 48 premolars were endodontically treated. After one week, the root canals were prepared to simulate an oversized root canal, except for the positive control group (PCG), which was cemented with a prefabricated fiber post (PFP) compatible with the root canal size, simulating an ideal adaptation. The other samples (n=8/group) were used to test alternative restorative techniques for filling root canals: negative control group (NCG [PFP with a smaller diameter than of the root canal]), composite resin group - CRG, bulkfill group - BFG, self-adhesive cement group - SAG, and glass ionomer group - GIG. The posts were cemented and after 1 week, each root was sectioned transversely into six 1-mm thick discs and the push-out test was done to evaluate the BS. Data were analyzed by two-way repeated measures ANOVA and Tukey's tests (α=0.05). The highest BS value was observed for PCG. The NCG and the GIG groups showed the lowest BS values. Root reinforcement with conventional and bulk-fill composite resins showed the highest BS values; however, the bulk-fill resin was the only treatment able to maintain high BS values in all regions of the root canal. The self-adhesive cement showed intermediate results between CRG and GIG. Root reinforcement with bulk-fill composite resin is an effective option for flared root canals before cementation of a prefabricated fiber post.
Highlights
Posts and cores of cast metal alloy can adapt intimately to the remaining root structure but study findings have shown that the produced wedging effect under the action of occlusal forces, associated with the high modulus of elasticity of metal post[1] can lead to catastrophic fractures of the roots.[2]
Bond strength values of fiberglass post to f lared root canals reinforced with different materials core of high diameters, endodontic over-instrumentation, incomplete physiological root formation, internal resorption, traumatic dental injuries or even root canals with an oval shape.[4]
The polymerization shrinkage that results from thick layers of resin cement can induce structural discontinuities at the dentin/ cement and cement/post interfaces such as bubbles, gaps, and fissures, which in turn, are responsible for a reduced retention of posts to root canals.[5]
Summary
Posts and cores of cast metal alloy can adapt intimately to the remaining root structure but study findings have shown that the produced wedging effect under the action of occlusal forces, associated with the high modulus of elasticity of metal post[1] can lead to catastrophic fractures of the roots.[2] fiberglass posts have substantially replaced metallic posts for intraradicular retainers, as they have a modulus of elasticity similar to dentin,[1] reducing the number of root failures.[3]. Because fiberglass posts are pre-fabricated, they do not always adapt well to the root canal. The polymerization shrinkage that results from thick layers of resin cement can induce structural discontinuities at the dentin/ cement and cement/post interfaces such as bubbles, gaps, and fissures, which in turn, are responsible for a reduced retention of posts to root canals.[5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
