IADR Abstract Archives
Bonding to Sclerotic Dentin: Effect of Etching Strategies and Pulpal-Pressure
Objective: To evaluate the influence of etching strategies on microtensile bond strengths (µTBS) of sclerotic dentin under different simulated pulpal pressure.
Method: 27 extracted (caries-affected and intact) molars were selected and middle dentin exposed. All caries-infected dentin was mechanically removed to expose sclerotic dentin. The teeth were randomly assigned into 9 experimental groups according to the dentin condition (intact or sclerotic), etching time (15 or 30s), and simulated pulpal pressure (0, 5, and 20cm). All teeth were restored using a two-step etch-and-rinse adhesive (Single Bond Plus, 3M ESPE) and a microhybrid resin composite (Z250, 3M ESPE). The samples were sectioned in X/Y directions to obtain specimens with a cross section of 0.8±0.2 mm² and submitted to µTBS testing. All sticks were fractured by tension at a crosshead speed of 1.0mm/min and the data were submitted to Kruskal-Wallis and Mann-Whitney Tests (α=.05).
Result: (Pre-testing failure/number of specimens) Mean±SD in MPa.
Dentin
| Etching
| Pulpal Pressure
| ||
(PTF/n) 0cm
| (PTF/n) 5cm
| (PTF/n) 20cm
| ||
Intact
| 15s
| (0/79) 53.78±17.3aA | (7/80) 29.05±16.6bA | (56/91) 17.76±26.2cA |
Sclerotic
| 15s
| (2/76) 45.05±17.1aB
| (1/79) 37.75±15.3bB | (23/83) 25.18±20.9cB |
30s
| (0/72) 49.16±12.1aB | (2/63) 50.33±16.2aC | (8/61) 33.33±19.6cC | |
Means with same lower-case letters, in the row, are not statistically different. Means with same upper-case letters, in column, are not statistically different. | ||||
Conclusion: The increase in pulpal pressure negatively influences bond strengths. The increase in pulpal pressure jeopardized the bond strengths, irrespective of the dentin substrate tested. Higher bond strengths were obtained when sclerotic dentin was etched for double of the recommended time.