Change of enamel after Er:YAG and CO2 laser irradiation and fluoride treatment.

OBJECTIVE

Our aim was to compare acquired acid resistance in dental enamel after Er:YAG and CO(2) laser irradiation in vitro with additional fluoride treatment.

BACKGROUND DATA

The application of lasers in dental hard tissue can impact dental constituents and fluoride with complex interactions.

METHODS

Bovine enamels were divided into four groups according to their surface condition: unlased, Er:YAG laser-ablated, fluoridetreated after Er:YAG laser ablation, and CO(2) laser-irradiated after Er:YAG laser and fluoride treatment. Calcium distribution in enamel after pH-cycling process and crystallographical change after laser treatment were evaluated.

RESULTS

The crystallinity of enamel was much improved after Er:YAG laser ablation. The CO(2) laser irradiation in the fluoride-treated laser enamel formed alpha-TCP and fluorapatite. The change of calcium distribution in enamel was least in the CO(2) laser-irradiated specimens; the fluoride-treated specimen after Er:YAG laser ablation was next. Additional fluoride treatment both after Er:YAG and before CO(2) laser irradiation improved the acid resistance of enamel.

CONCLUSION

Both external treatment of fluoride and irradiation of CO(2) laser after Er:YAG laser ablation greatly reduced calcium loss in enamel during the pH cycling process.