Er:YAG-laser on fluoride uptake in silver diamine fluoride treated dentine

Abstract

Objective: To evaluate fluoride uptake in 38% silver diamine fluoride (SDF) treated dentine with different Er:YAG laser (2940 nm) sub-ablative energy densities. Method: Two 8×8×3mm3 dentine slices were prepared from 2 sound human molars. Each slice was divided into 4 areas for application of 38% SDF as control (group 1), SDF application followed by Er:YAG irradiation at 0.6 J/cm3 (group 2), SDF application followed by Er:YAG irradiation at 0.8 J/cm3 (group 3) and SDF application followed by Er:YAG irradiation at 1.0 J/cm3(group 4). The laser irradiation was set at a 1,000 µs pulse, 10Hz repetition rate at 3mm spot size applied for 20 seconds without water. Fluoride uptake (weight %) of the 4 groups was assessed using Energy Dispersive X-ray Spectrometry (EDX) at 0, 5, 10, 15, 20µm depth from the SDF-treated dentine surface. Separate two-way mixed model analysis of variance (ANOVA) was used to compare mean fluoride weight % among four groups at different levels with sample as a random effect.

Result: The fluoride content in weight % (±SD) in Group 2 was 22.6±7.3, 11.3±6.3, 9.2±4.3, 6.8±3.2 and 7.7±4.3 at 0, 5, 10, 15 and 20µm depth levels, respectively. Pairwise comparison of estimated marginal means with Bonferroni adjustment showed that these were significantly higher than those in group 1, 3 and 4 at all levels (p<0.05).

Conclusion: Er:YAG laser sub-ablative energy densities at 0.6 J/cm3 gave the highest fluoride uptake effect on SDF treated dentine. The fluoride uptake was highest on the surface.

This study is supported by the HKU Seed Funding Programme for Basic Research 201111159079.