Surface layer phenomena in in-vitro early caries-like lesions of human tooth enamel

In this study a buffer system containing calcium and phosphate was used to produce caries-like lesions. The influence of the pH on the lesion characteristics was investigated. The degree of saturation with respect to hydroxylapatite and the concentration of the undissociated acid were kept constant. The pH was either 4.0, 4.5, 5.0 or 6.0. The lesions were examined microradiographically. The lesion characteristics studied were: the mineral content of the surface layer; the mineral content of the body of the lesion; the depths at which these mineral levels were reached, and the depth of the lesion. The most important influence of the pH was that on the rate of demineralization. A striking phenomenon was the sudden change in the rate at which the different levels of demineralization were reached. In solutions with a pH lower than or equal to 4.5, the time needed to reach a certain demineralization was considerably shorter than for solutions with a pH higher than or equal to 5.0.

Section: Discussionsupporting

confidence: 53%

Effect of the pH of Buffer Solutions on Artificial Carious Lesion Formation in Human Tooth Enamel

Theuns¹,

Dijk²,

Driessens

et al. 1984

“…Hence it is important to consider the threefold faster rate of lesion formation in bovine compared with human enamel when using data from two enamel types. This is also of importance when con sidering quantitatively surface layer forma tion and the mechanism of outer surface protection, be it by adsorbed material [Featherstone et al, 1978b[Featherstone et al, , 1979, by partial saturation [Larsen, 1974], or by a combina tion of both [Zahradnik et al, 1976]. The relative lesion formation rates and diffusion coefficients found in the present study will assist in future calculations of this nature based on one or more of the enamel types listed here.…”

Section: Discussionmentioning

confidence: 84%

Relative Rates of Progress of Artificial Carious Lesions in Bovine, Ovine and Human Enamel

Featherstone¹,

Mellberg²

1981

Self Cite

166

104

Artificial carious lesions were produced by a gelatin/lactic acid system in deciduous bovine, permanent bovine, deciduous human and permanent human enamel over periods up to 8 days, and the progress measured by dye imbibition studies. Artificial carious lesions were produced in bovine, ovine and human permanent enamel using a diphosphonate/lactic acid system over periods up to 30 days, progress was assessed by depth measurement, and overall diffusion coefficients were calculated. The rate of lesion progress was linear with the square root of time for both systems of assessment. Lesion progress as measured by dye imbibition was in the ratio 3.7: 2.9: 1.5:1.0 for bovine deciduous: bovine permanent: human deciduous: human permanent, respectively. Bovine permanent, ovine permanent and abraded bovine permanent lesions progressed at equal rates and in the ratio 3.0: 1.0 to human permanent enamel, as measured by overall diffusion coefficients. The results provide an approximate basis for the use of bovine, ovine and human artificial carious lesion data in the quantitative discussion of the caries process.

“…Although many of the previous remineralizing studies have been done on etched enamel our work on the demineralization aspects of dental caries [Featherstone et al, 1978[Featherstone et al, , 1979a sug gests that remineralization rates will be related to subsurface effects and diffusion. Ten Cate and Arends [1977] also illustrated the importance of us ing subsurface artificial lesions to study remineral ization.…”

Section: Artificial Carious Lesionsmentioning

confidence: 99%

“…Gray, Procter & Gamble). Previous work [Featherstone et al, 1978[Featherstone et al, , 1979a has shown that this system pro duced artificial lesions with several of the charac teristics of early natural lesions, and that a mini mum period of 5 days is required for the develop ment of a well-formed intact outer layer.…”

Section: Artificial Carious Lesionsmentioning

confidence: 99%

“…The crowns of approximately 300 extracted human molars or premolars with at least one car ies-free surface were brushed with hot detergent solution, rinsed in distilled water and air dried [Featherstone et al, 1978], All crowns were then coated with nail varnish, except for an area ap proximately 9 mm2 on one surface. The samples were immersed individually in 40 ml of buffer sol ution without agitation at 37 °C for periods from 7 to 30 days.…”

Section: Artificial Carious Lesionsmentioning

confidence: 99%

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Physicochemical Requirements for Rapid Remineralization of Early Carious Lesions

Featherstone

Rodgers

Smith³

1981

Self Cite

Physicochemical data related to remineralization of carious lesions were determined. Diffusion properties of calcium ions, fluoride ions, calcium-anion complexes, and cation-fluoride complexes were studied using protein-impregnated and protein-apatite-impregnated membranes. Stability constants of metal-fluoride and amine-fluoride complexes were determined by titration. Artificial carious lesions were produced in human enamel and immersed in remineralizing solutions containing calcium, zinc, strontium, phosphate, acid anions, fluoride and organic cations at various pH levels. Selected samples were reimmersed in demineralizing solution. Sodium fluoride, acidulated phosphate-fluoride and calcium-phosphate fluoride solutions were tested similarly. Calcium-anion complexes diffused rapidly through protein gels. Metal-fluoride complexes were generally too weak to affect diffusion rates but some cations enhanced fluoride transport. Partial remineralization of lesions occurred with the new test solutions more rapidly than with traditional fluoride preparations, and further demineralization was markedly reduced. Remineralizing solutions based on this new hypothesis show promise as an improved caries preventive measure.