RESIN BOND STRENGTH WITH DIFFERENT METHODS TO REMOVE EXCESS WATER FROM THE DENTIN

Purpose, To compare the resin bond strength using different methods to remove the excess water from the dentin while maintaining it moist. M aterials and Methods: 60 human molars were randomly divided into four treatment groups of 15 teeth each as follows: Group 1: A wet bonding t echnique was used as recommended by the manufacturer and was used as a control group. The exposed occlusal dentin surfaces were conditioned with 32% phosphoric acid (Uni-Etch) for 15 seconds and rinsed for 15 s econds. 40 mu L of distilled water was added to standardize the conten t of the water on dentin surface. The conditioned dentin surfaces were gently blow-dried for 3 seconds with oil-free compressed air; The tip of the syringe was placed at 2 cm from the dentin surface. One coat o f the One-Step primer/adhesive was applied to the dentin surface using a fully saturated brush tip, allowed to remain on the surface: undist urbed for 3 seconds, and then gently air-dried for 3 seconds from a di stance of 1 cm to remove excess solvent and water. A second coat of th e primer/adhesive was applied and gently air-dried from a distance of 1 cm. The primer/adhesive was light-cured for 10 seconds. Resin compos ite (Z100, shade A3) was then polymerized for 40 seconds.-Group 2: The dentin surface was blot-dried by applying tissue paper (Kimwipes EX-L ) adjacent to the exposed area; Group 3: The excess water on the denti n surface was removed using an applicator brush (Bend-a-Brush) for 5 s econds, Group 4: A small dry hydrophilic cotton pellet was gently appl ied over the dentin surface to remove the excess water. The sequential steps for these three groups were similar to those of Group 1. The de ntin surface remained visibly moist in all procedures. After light-cur ing, the specimens were thermocycled (5 degrees and 55 degrees C, 500 cycles, 30-second dwell time). The specimens were sheared-and the data were analyzed using ANOVA and Tukey's test methods. The site of failur e was analyzed using a stereomicroscope and a scanning electron micros cope. Results: ANOVA revealed-that there was a statistically significa nt difference between the groups (P<0.05). Tukey's test revealed that Group 1 was significantly lower than Groups 2, 3 and 4 with no differe nce between the last three groups (P<0.05). All samples showed resin c ohesive failures.