Optimal use of silver nitrate and marginal leakage at the sealant-enamel interface using micro-CT

To investigate the optimal silver nitrate concentration and tooth immersion period for assessing marginal leakage at the sealant-enamel interface, using micro-CT.

Two experiments were conducted, using eight teeth sealed with a resin composite without etching, in dried but not desiccated, pits and fissures. Five teeth were immersed in 50% silver nitrate for 0, 1, 2, 3, and 4 hours and scanned, using micro-CT, and two evaluators using a newly developed index assessed marginal leakage at the sealant-enamel interface (Experiment A). Experiment B was carried out in the same way as Experiment A, with the difference that teeth were immersed in 50% and 60% silver nitrate for 2 and 3 hours. Reliability of scores was estimated, using weighted kappa coefficient. ANOVA and t-test were applied to test for period and concentration effects.

Reliability of collected data was substantial. A statistically significant difference was observed between 50% silver nitrate penetration scores at 0-1 and 2-4 hours of immersion (P < 0.0001) but not between 50% silver nitrate penetration scores at 2-, 3-, and 4-hours of immersion (P > 0.05) (experiment A). Analysis in experiment B showed a period effect (P = 0.03) but no concentration (P = 0.07) and interaction effect (P = 0.64). Combining all data from 50% silver nitrate immersion, analysis showed no statistically significant difference in penetration scores between 2, 3 and 4 hours of immersion (P = 0.33). The newly developed index showed substantial reliability.