Bond Strength of Fiber Post Treated by Cojet System

Objectives: The purpose of this study was to evaluate the effect of surface treatment by the Cojet system (3M-ESPE) on the retention of glass fiber posts. Methods: 30 Snowpost, 30 Snowlight (Carbotech), 30 Aestheti-Plus, 30 Light-post (RTD), 30 FRC Postec (Ivoclar-Vivadent) were used and randomly divided into 3 groups according to the surface treatments : G1: no surface treatment ; G2: dual-cure bonding agent, Prime&BondNT + Self Cure Activator (Dentsply); G3: Cojet system consisted of air abrasion with an intra oral sandblasting device using 30 µ silicate-coated particles, followed by silane coating with ESPE-SIL(3M ESPE). Shear bond strength measurements were realized with a specially designed experimental apparatus for push-out testing. The posts were centered in a dedicated teflon mold and embedded in a light-cure composite Lumiglass (RTD). 6 mm high and 8 mm wide cylindrical specimens were obtained. The push-out strength was calculated using the formula: σ=F/πTD (F:Force, T:Thickness of the specimen and D: Diameter of the post). Results: Shear bond strength: mean (SD) in Mpa: Snowpost:G1=18.6(2.3), G2=24.2(1.7), G3=33(2.5); FRCPostec:G1=18.8(2.1),G2=28.5(2.8), G3=42.6(2.6);Snowlight:G1=16.2(1.9), G2=20(1.7), G3=29.6(1.7);Aestheti-Plus:G1=22.5(2.7), G2=30.1(2.5), G3=41.3(2.4);Light-Post: G1=18.5(2.6), G2=23.5(2.6), G3=31.3(1.6) Data were compared using ANOVA supplemented with Fisher's PLSD at a significance level of p=0.05. Bond strengths of G3 were significantly higher compared to G2 and G1 independently of the posts. Conclusion: In addition to providing microretentive roughening, silicatized Cojet Sand allows a ceramic-type coating of the surface of the material. Silanization with ESPE SIL provides a chemical bond between the silicate layer and the methacrylate groups of dual cure-bonding agent. This study showed that Cojet treatment could offer better retention whatever the glass fiber post used.