Performance of luting-agents on bond strength on coronal and root-dentin

Objectives: The aim of this study was to evaluate the performance of different luting-agents on the bond strength of laboratory resin of coronal (Microtensile test- MTBS) and root (Micropush-out test - MPT) human dentin.

Methods: Thirty human third-molars were grounded to expose occlusal dentin with 600-grit abrasive-paper. Teeth were randomly divided into three groups (n=10). Restorations were manufactured with laboratory resin (Sinfony, 3M-ESPE) and fixed with: Cc1- dual-cure resin cement RelyX ARC; Cc2- resin modified glass ionomer cement (RelyX Luting); Cc3- self-adhesive dual-cure resin cement (RelyX U100). After 24 hours specimens were cut in slices and trimmed to create hourglass-shape with of 1.0 mm2 cross sectional area (4 per teeth). The samples were submitted to MTBS. For root dentin, thirty extracted non-carious single-root human teeth were selected, the crows were removed and the root canals were treated. Samples were divided into three groups (n=10). Cylindrical restorations simulating a root post were manufactured with laboratory resin (Sinfony), and fixed with: Rc1- RelyX ARC; Rc2- RelyX Luting; and Rc3- RelyX U 100. Teeth were cut perpendicular to their long axis to obtain a series of 1.0 mm thick disks (6 per teeth). The samples were submitted a MPT. MTBS and MPT data were analyzed with 1-way ANOVA and Tukey Test (p<0.05). Results: Premature failures for MTBS were: Cc1:18; Cc2:31; Cc3:23, and for MPT test were - Rc1:1; Rc2:0; Rc3:0. Any sample of Cc2 was tested, means and standard deviation (MPa) were: MTBS: Cc1:17.7±5.0^a; Cc3: 9.7±4.0^b; Cc2: 0.0; and for MPT test were - Rc3:10.9±1.5^a; Rc1:5.7±1.4^b; Rc2:3.5±0.8^c(Different letters represent significant difference means in each dentin region).

Conclusion: The performance of luting agents was determined for indication. For coronal dentin the RelyX ARC produced the best results and into the root canal the RelyX U100 resulted in the best results.