Acid Susceptibility at Various Depths of pH-Cycled Enamel and Dentine Specimens

Abstract

pH-cycling and in situ studies have shown that fluctuations in de-/remineralisation conditions or in fluoride usage can lead to laminations inside enamel or dentine lesions. Layers with different mineral content are thought to reflect the history of fluoride administrations. Studying the dissolution properties of such lesions at various depths – using bulk specimens – is presumably hampered by limited diffusion of acids through the lesion pores. Therefore, in this study the acid susceptibility of enamel and dentine lesions and the underlying sound tissues was studied by exposing sections to acid buffers from the cut rather than from the external surface. Specimens were obtained from a previous study of the effects of high-fluoride (0, 1,000, 2,000, 3,000/5,000 ppm F) toothpastes on enamel and dentine de-/remineralisation. Sections were subjected to acid buffers for 3 and 7 days and the changes in mineral content were monitored by contact microradiography. For enamel lesions a significant difference in dissolution over depth was observed between the groups subjected to the different fluoride schemes. At 7 days a dose response was found between the different fluoride groups and the lesion parameters. In the no-fluoride group dissolution in the original lesion and the sound tissue were similar. All dentine lesions which had been treated with fluoride showed inhibition of dissolution, but the inhibition did not increase with higher fluoride concentrations. Deeper into the dentine tissue there was some protection, but it was not statistically significant. We conclude that penetration of fluoride through the lesion pores determines the dissolution pattern of a lesion at various depths.

Effect of compounds of Galla chinensis and their combined effects with fluoride on remineralization of initial enamel lesion in vitro

“…Previous studies had indicated full remineralization was unable to achieve even with high concentration of fluoride. 26 Our shortterm experiment showed GCE and gallic acid had combined effects with fluoride, but the mechanism was still unknown. More studies were needed to investigate whether G. chinensis could promote the effect of fluoride or they could enhance remineralization separately without inhabitations.…”

Impact of Experimental Nano-HAP Pastes on Bovine Enamel and Dentin Submitted to a pH Cycling Model

“…The pH-cycling model chosen for enamel and dentin was based on previous studies each focusing on one type of dental substrate (3,21,22). The models should be able to simulate the demineralizing and remineralizing episodes, considering the composition of the different dental substrates, in order to create a subsurface mineral loss and not an erosive lesion (10 µm deep) at the end of the experiment.…”

“…On the other hand, the evidence of an increasing prevalence of dental fluorosis (2) and some fluoride limitations, such as the inability to completely remineralize carious lesion (2,3), have led to the search for alternative non-fluoride agents that could provide a complete prevention or arrest of dental caries lesion (4).…”

Effect of Galla chinensis extract and chemical fractions on demineralization of bovine enamel in vitro

“…18 Among all the models, pH-cycling system is the most popular which mimics the periodic exposure of enamel and dentine to de-/remineralization conditions and to fluoride. 19 In the present study, we followed the regime proposed by Lynch in 2002. 16 Bovine enamel was used because it was easy to obtain and provided a less variable response to both cariogenic challenge and anti-caries treatments comparing with human teeth.…”