Core Rebuilding Using Quartz/Carbon Fiber Posts: in Vitro Study

The possibility of using quartz fiber endodontic posts instead of carbon fiber post also in the rebuildings of molar teeth is still under investigation.Objectives:the aim of this in vitro study is to evaluate the resistance to 90° applied forces of composite cores rebuilt by using 1 or 3 carbon fiber posts and 1 or 3 quartz fiber posts.Methods:20 model teeth (Frasaco AG-3ZPUK-46),divided into 4 groups of 5 elements were sectioned at the same level and rebuilt with composite under identical forms(Composipost Core Form, RTD)using fiber-reinforced posts as following:Group A:1 carbon fiber post (Endocomposipost, RTD).Group B:1 quartz fiber post(Endolightpost,RTD).Group C:3 carbon fiber posts.Group D:3 quartz fiber posts.Shear Bond Strength Test(SBST)with Instron machine was performed with forces perpendicular to long axis ofteeth.Results:the average resistence was:Group A:10.03 MPa.Group B:18.43 MPa.Group C:20.80 MPa. Group D:32.10 MPa. Conclusion:1)a higher resistance to SBST of composite cores built onto quartz fiber posts is evident;2)using 3 instead of 1 carbon fiber post the resi-stance is doubled;3)using 3 instead of 1 quartz fiber post the resistance increases of 75%.The above results suggest that the use of 3 quartz fiber posts in composite rebuildings of molar teeth leads to the highest resistance to 90°-applied loads,and seems to be the right choice in complex post-endodontic restorations.