A set of interrelated physical models has been developed for use in the rational design of laser irradiation regimens for improving the resistance of tooth enamel to dental caries. Taken together, these models describe (1) the formation of subsurface lesions in dental enamel; (2) the dependence of this lesion formation on micro-environmental solution chemistry variables such as pH and concentrations of calcium, phosphate and fluoride; (3) the dependence of this lesion formation on the metastable equilibrium solubility; (4) the alteration of the MES of enamel by exposure to elevated temperatures and (5) the time-temperature profiles achieved by laser irradiation of enamel. Appropriate laboratory procedures have been developed and carried out to determine the values of the relevant parameters of each of the above models. Key findings are: (1) the onset of dissolution is controlled by the micro-environmental solution ion activity product (IAP) for fluorapatite; (2) the value of this threshold IAP can be shifted significantly by laser irradiation; (3) this IAP shift corresponds to a lowering of the threshold pH for onset of demineralization by about 0.7 pH units; and (4) the set of models listed above can be used together in an integrated approach for the rational design of laser irradiation regimens for improving resistance to dental caries.

Date Published: 23 April 1996
PDF: 12 pages
Proc. SPIE 2672, Lasers in Dentistry II, (23 April 1996); doi: 10.1117/12.238757

Published in SPIE Proceedings Vol. 2672:
Lasers in Dentistry II
Harvey A. Wigdor D.D.S.; John D. B. Featherstone; Joel M. White D.D.S.; Joseph Neev, Editor(s)