Different Technique in Core Rebuilding onto Quartz Posts:Experimentel Study

The more effective technique in composite core rebuilding about quartz fiber endodontic post is still uncertain.Objectives: The aim of present in vitro study is to evaluate if layering onto the coronal part of quartz fiber posts the composite cement which flows back from root canal increases the core-to-post adhesion.Methods:2 composite cements, self-curing (C&B,Bisco)and dual curing (Duo Link, Bisco) were used in luting into a prefabricated model quartz fiber posts (Endolightpost, RTD). Cements were layered on the posts surface,and 2 different composites (Light Core,Bisco,and Aeliteflo,Bisco)were used to build a core onto the posts;4 groups of 5 elements were obtained. Cores were built by using identical plastic forms (Composipost Core Form,RTD). Slices of 2.2 mm thickness were obtained and subjected to pull-out test with Instron machine. Results: Group 1(C&B + Light Core)=33.0 MPa. Group 2(C&B + Aeliteflo) =31.8 MPa. Group 3(Duo Link + Light Core) = 40.0 MPa. Group 4(Duo Link + Aeliteflo)=38.2 MPa. Conclusion:a)layering composite cement flowed back from root canal onto the coronal part of quartz fiber posts leads to better results in core-to-post adhesion,which was calculated in a previous in vitro study 21.31 MPa by using the same composite (LC) directly and step-by-step onto the post;2) dual composite cement layered onto the post shows better performances than self-curing cement;3)only negligible difference in post-to-core adhesion exists between flowable and non-flowable composite used with a plastic form in core rebuilding.