Methods: 18 freshly extracted human molars were used for this study. Standardized class II cavities in the mesial (enamel margin) and distal (dentin margin) surfaces were restored with Biodentin®. The teeth were randomly divided into 3 groups : 1 : direct application of Biodentin® ; 2 : treatment of the wall of cavity with polyacrylic acid before restoration ; 3 : application of Optiguard on Biodentin® surface. The specimens were stored at 37°C one day, thermocycled, stained, sectioned twice longitudinally in the mesio-distal direction. The silver nitrate penetration was measured.
Results:
Groups enamel margin (%) dentin margin (%)
1 : 17,65(± 4,38)(a) - 10,46 (± 3,23)
2 : 8,53 (± 7,44) (b) - 1,83 (± 3,94)
3 : 46,5 (±10,55)(a)(b) - 8,31 (± 4)
Same letters indicate significant differences (p < 0.05)
There was no statistically significant difference in microleakage between with and without treatment of enamel/dentine surface with polyacrylic acid. The microleakage at the enamel - Biodentin® interface with treatment of Optiguard® is more important than without (p<0.05). The cement particles are hydrophilic. After 1 day, the cement reaction was not achieved yet. It was observed that the Optiguard® layer limits the water contact with cement preventing the hydration phenomenon. The surface of the dentine is wetter than that of enamel explaining why no influence of Optiguard® on the microleakage at the Biodentin® - dentine interface was observed.
Conclusion: These data show the good sealing ability of this new material. However the setting time as to be considered regarding the short term results.