REHARDENING OF SOFTENED TOOTH ENAMEL,
Abstract
If enamel surfaces are exposed to freshly prepared solutions of calcium and phosphate salts above pH 6.9, the softened enamel may be rehardened. Optimal conditions at 37 degrees are approximately: calcium concentration, 1 to 2 mM/1; Ca/P ratio 1.67; pH 7.3; and fluoride concentration, 0.05 mM/1. The solutions are metastable, and the pH drops below 6.9 after 30 to 60 min. Fresh calcifying solutions are used when the pH drops below 6.9. Under such conditions, the hardness may be increased from 150 KHN to about 300 KHN in 3 to 4 hr. When the teeth had been previously softened below about 150 KHN, the recovery after exposure to rehardening solutions was less complete. Such solutions produce an increase of about 10 per cent in the hardness of ground surface enamel and of intact surface enamel, not softened previously. Saliva alone produces some rehardening of softened enamel, and the conditions affecting this action of saliva are under study. Freshly prepared rehardening solutions were incorporated in the bacteriological medium used for the production of in vitro caries by oral bacteria. Calcium, phosphate and fluoride ions were studied singly and in all combinations. The combination of all these ions, as expressed for the optimal conditions above, completely inhibited the in vitro caries. The combination of calcium and fluoride ions inhibited significantly, but the other combinations were relatively ineffective. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1963
- Accession Number
- AD0615668
Entities
People
- H. Cueto
- T. Koulourides
- Ward Pigman
Organizations
- New York Medical College