Bond strength to intraradicular dentin - Effect of bonding strategy

Purpose: To verify if the use of an activator with a self-etching bonding system can influence the intraradicular bonding strength and compare this bonding with a total-etch one-bottle dual-cure bonding system. Methods: Twenty-eight recently extracted premolars were endodontically treated and randomly assigned to 4 groups (n=7). Fiber glass posts (Reforpost Mix n.3 - Angelus) were luted with a resin cement (Enforce, Dentsply) associated with the following: G1: a total-etch one-bottle dual-cure bonding system (Prime&Bond NT + Self Cure Activator, Dentsply); G2: a self-etch bonding system (Xeno IV, Dentsply); G3: a self-etch dual-cure bonding system (Xeno IV + Self Cure Activator, Dentsply), and G4: a self-etch dual-cure bonding system (Xeno IV + Experimental catalyst, Dentsply). After twenty-four hour storage, roots were cut in three levels (cervical, middle, apical). Push-out tests were carried out in each root section and the bond strengths in MPa were obtained. Data were analyzed by Kruskal-Wallis test (level of significance of 9.91%). Results: The bond strength averages in MPa of the groups were: G1= 4.6±3.9; G2=5.0±3.0; G3=3.1±3.2; G4=5.7±4.3. There is no statistically difference among the groups tested. The cervical third averages (7.6±3.7MPa) were significantly greater than middle (3.1±2.8 MPa) and apical (3.2±2.9) third averages. Conclusions: The use of a catalyst showed no advantage in the intraradicular bonding with dual-cure resin cements using self-etching adhesive systems. The cervical root region presented higher bond strength than middle and apical.