|Budget Amount *help
¥2,400,000 (Direct Cost : ¥2,400,000)
Fiscal Year 1997 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1996 : ¥1,400,000 (Direct Cost : ¥1,400,000)
We studied F^- uptake of enamels by simultaneously acting excimer laser irradiation (ultraviolet zone) and various percentages of F^- solution (photochemical reaction). These enamel specimens were polished up to 200mum from 4-faced surfaces of an extracted molar. They were divided into 4 groups the double acting group of F^- solution and irradiation, the group of F^- coating, the irradiation group, and the control group. The 248nm KrF laser consisting of 70mJ/cm^2 500-5,000 shots and 0.1-4.0% of F^- solution (NaF and MFP) was used. After washing out the enamel speciments with 1M-KOH for 24 hours, the surfaces were observed by SEM and XPS,and acid resistance was tested. Cellulose acetate menmbranes adding 0.1M Lactic acid buffer (pH4.0,2mul) were attached at the speciments for one minute. Eluted Ca amounts were analyzed by ICP.Because of the results of the SEM and XPS,it was suggested that photochemical reaction was induced by irradiation. There were significant differences of acid resistance among the groups (p<0.05, one way ANOVA). Eluted Ca amounts of each group which triggered NaF of 4.0 from 0.1% was 0.34-0.50mug with the double acting froup, 0.55-0.69mug with the coating group, 0.59-0.77mug with the irradiation group, and 0.65-0.88mug with the control group. The double acting group with 1%F^- (NaF) was strongest, with acid resistance tending to be weaker in order of the coating group, the irradiation group, and the control group. This group showed a 51.0% effect compared with the control group.