EFFECTS OF ND:YAG LASER IRRADIATION AND FLUORIDE APPLICATION ON REMINERALIZATION OF THE ENAMEL

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Journal of the Korean Academy of Pediatric Dentistry 2004;31(3):381-390.
Published online August 31, 2004.

EFFECTS OF ND:YAG LASER IRRADIATION AND FLUORIDE APPLICATION ON REMINERALIZATION OF THE ENAMEL

Nd:YAG 레이저 조사와 불화물 도포가 탈회법랑질의 재광화에 미치는 영향

조현, 김대업, 이광희

원광대학교 치과대학 소아치과학교실.원광치의학연구소

Correspondence: ,

Abstract

The purpose of this in vitro study was to investigate the effects of Nd:YAG laser irradiation and fluorides on acid drink demineralized enamel. The materials were 30 freshly extracted permanent premolars with intact smooth enamel surfaces. They were demineralized with Coca-cola at 37℃ for 12hours and then irradiated by Nd:YAG laser with 6W power, 50mJ/cm² energy density, and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides; (1)0.05% NaF fluoride solution (2)1.23% APF gel and (3)0.1%F fluoride varnish, microhardness(VHN) and Diagnodent scores were measured and the surfaces of each treated specimens were also observed with SEM under 1500 magnification. The results were as follows: 1. In the change of microhardness(VHN), it decreased to 34.68% from the initial micrhardness, increased to 78.37% after laser irradiation and increased to 82.62% after fluoride treatment, there were significant differences except when it was irradiated and treated with fluoride(P<0.05). 2. In the change of Diagnodent scores, it was decreased to 28.08% from the initial scores after demineralization, and then increased to 59.81% after laser irradiation, and increased to 82.17% after fluoride treatment. Scores were different significantly between the scores of initial, demineralization, laser irradiation and fluoride treatment(P<0.05). All the scores were not different significantly between fluoride types. 3. SEM observation showed that the lased enamel surfaces after demineralization were thermally degenerated and showed molten lava-like appearance and crater with cracks and many microholes.

Key Words: Nd:YAG laser, Fluoride, Remineralization of the enamel