A Morphological in Vitro Study of the Effects of Nd:YAG Laser on Irradiated Cervical Dentin

Objective: The purpose of this in vitro study was to verify the efficacy of Nd:YAG pulsed laser at 1064 nm in sealing dentinal tubules in vitro, with its resulting morphological changes using clinical parameters applicable to the treatment of dentin hypersensitivity. Background Data: Although many papers have been written on the subject, no rapid, efficient, and long-lasting treatment for this problem has been developed. Materials and Methods: Twenty healthy extracted human teeth were kept in saline solution. Cervical cement was removed with a no. 57FG bur to expose approximately 4 mm² of dentin. Two groups were in the buccal aspect (A and B–irradiated) and one group in the lingual aspect (C–control not irradiated) of the same tooth. Samples with a remaining dentinal thickness between 1 and 1.5 mm were selected. Irradiation parameters were 30 mJ, 0.3W(Group A) and 40 mJ, 0.4 W(Group B); 7 Hz was used in both groups in two 43-sec applications each, with a 10-sec interval. In 10 samples, the dentinal surface underwent SEM examination for study. The other 10 remaining irradiated samples were centrally cleaved to study laser penetration depth in dentin (SEM). Results: Obliteration of dentinal tubule openings and solidification of the dentin surface were observed in all irradiated samples. Laser penetration depth in dentin (SEM) varied from 1 to 7 µm, depending on irradiation parameters used in each group. Conclusion: We concluded that the use of the Nd:YAG laser was a very effective measure for obliterating dentinal tubule openings.