DENTASTIC BOND STRENGTH TO DENTIN

Purpose: To evaluate the shear bond strength to the dentin of permanen t teeth and failure site of Dentastic hydrophilic dentin bonding agent . Materials and Methods: Forty permanent noncarious molar teeth stored in distilled water were obtained. The teeth were cleaned with pumice and a rubber cup. The mesio-buccal surface of the teeth was ground fla t with hand pressure with a series of SiC paper ending with the 600 gr it to provide a uniform surface on dentin to which the resin composite could be applied. After preparing the tooth surface, the teeth were s tored in distilled water for 48 hours. They were then divided at rando m into four groups of 10 specimens each: Group 1: Dentastic, five coat s of primer; Group 2: Dentastic, three coats of primer; Group 3: Denta stic, five coats of primer, light-cured adhesive before resin bonding; Group 4: Dentastic, three coats of primer, light-cured adhesive befor e resin bonding. All specimens were thermocycled (500x) and sheared in a testing machine. After shear testing, the debonded sites of all sam ples were examined with a stereomicroscope and a scanning electron mic roscope. Results: The results in MPa were: Group 1: 22.63 +/- 6.24; Gr oup 2: 23.35 +/- 5.14; Group 3: 23.58 +/- 5.66; Group 4: 27.26 +/- 8.2 2. ANOVA and Student-Newman-Keuls showed no statistically significant difference between the groups. In all groups, all specimens failed at the dentin (dentin cohesive failure = dentin fracture) or at the resin (resin cohesive failure = resin fracture). This means that the bond s trength of the product is stronger than the cohesive strengths of the dentin and the resin.