Micromorphological analysis of dentinal structure after irradiation with Nd:YAG laser and immersion in acidic beverages.

OBJECTIVE

The purpose of this study was to analyze dentinal surfaces that were exposed to acidic beverages, then treated with Nd:YAG laser and afterwards exposed to acidic beverages again.

BACKGROUND

Dentin hypersensitivity can result from surface erosion caused by acidic beverages, which exposes and enlarges the dentinal tubules. Nd:YAG laser has been used as a treatment option.

METHODS

Sixty-eight dentin samples were prepared and assigned to five groups: G1, control (n = 4); G2, 3-h immersion (n = 16); G3, 3-h immersion + Nd:YAG; G4, 3-h immersion + Nd:YAG + 3-h immersion; and G5, 3-h immersion + Nd:YAG + 6-h immersion. Each group was divided into four subgroups, with different acid beverages: lemon (n = 4); passion fruit (n = 4); cola (n = 4); and wine (n = 4). Irradiation with the Nd:YAG was in contact mode, focused and perpendicular through a quartz fiber of 300 microm of diameter in scanning movements for 60 sec with a 10-sec interval and the paramenters 0.6 W, 10 Hz, 60 mJ, and 85 mJ/cm(2). Each subgroup was examined by scanning electron microscope.

RESULTS

All the acidic beverages contributed to exposure and increased diameter of the dentinal tubules.

CONCLUSIONS

Irradiation with Nd:YAG laser produced obliteration of and reduction in the number of dentinal tubules, thus modifying the original structure.