抄録
This study demonstrated the chemical stability of remineralized enamel under various test conditions. Lesions were produced on bovine enamel slabs (N=20; 3×5mm) by a 2-day immersion in 0.01mol/l lactic acid buffer containing 3.0mmol/l Ca, 1.8mmol/l P, 1% CMC, adjusted to pH 4.0 and 37°C. The remineralizing solution contained the same amount of Ca, P, and CMC plus 150mmol/l NaCl and 3 ppm F, and was adjusted to pH 7.0 and 37°C. All slabs were exposed to this unstirred solution which was changed every two days during the 10-day remineralizing period. Each five remineralized slabs were divided into four groups. Group A (the control group) received no further treatment. The other three groups were exposed for 24 hours to either the intraoral environment (Group B), a 1.0mol/l KOH solution (Group C), or a 0.01mol/l lactic acid buffer (Group D).
Typical microradiographic pictures assessed by quantitative microradiography showed no clear difference in the radiographic density of the remineralized lesions in relation to the three test conditions. The range between maximum and minimum of mineral contents in vol % of five measurements at a certain depth were within 10%. Remineralization of the lesion appeared to be complete after the 10-day exposure. The result of the subsequent 1mol/l HClO4 treatment showed a radiopaque zone, concurrent with remineralized enamel, indicative of acid resistance. The lack of appreciable mineral change from enamel with any of the above conditions indicated a chemical stability of mineral in the remineralized enamel.
