|1490 Bond Strength of Dentin as a Function of Priming Time|
W. EL-BADRAWY, L. KOZOVSKI, G. NATHAN, and R.C. ROPERTO, University of Toronto, Canada|
Purpose: Under the time constraints of private practice time recommendations by materials' manufacturers can be easily overlooked. The aim of this study was to investigate the effect of varying dentin priming time on its bond strength to composite resin using a self-etching bonding system. Methods: Crowns of sound, freshly extracted, sterilized human molars were sectioned horizontally to expose flat and sound dentin. The sectioned teeth were examined microscopically to ensure lack of defects then divided randomly into 4 equal groups. Groups were assigned according to the time of dentin priming. Dentin surfaces of groups 1, 2, 3 & 4 were subjected to four different treatments using SE Bond primer (Kuraray, Japan). Group1 sections (control) were primed for 20 seconds as per manufacturer's recommendations. Group 2, 3 & 4 sections were primed for 5, 10 & 30 seconds, respectively. Bonding resin was then applied and cured for 10 seconds. Composite blocks were built-up and cured incrementally to 3mm thick (Spectrum, Caulk-Dentsply). All groups were stored for 24 hours at 37°C. Rectangular prisms specimens (6 x 1 x 1 mm) were cut from the bonded tooth sections. Microtensile bond strength testing was then conducted using a microtensile tester (Bisco). Results: Microtensile bond strength means and standard deviations in MPs for groups1, 2, 3 &4 were: 24.98 (7.2), 20.67 (5.5), 23.63 (6.7) and 22.72 (5.9), respectively. ANOVA testing showed no statistically-significant difference between the tested groups (P>.05). Conclusions: Although there was no statistically-significant difference in mean microtensile bond strength with the four different priming times, there was a 17% reduction in mean bond strength when priming time was reduced from 20 to 5 sec. Materials provided by Kuraray and Dentsply.
|Seq #180 - Bond Strength of Composites to Enamel and Dentin - Application, Technique|
2:00 PM-3:15 PM, Friday, March 23, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J