Effectiveness of Two Fluoridation Measures on Erosion Progression in Human Enamel and Dentine in vitro

Abstract

The aim of the present study was to evaluate the effect of fluoride on the progression of erosive demineralisation in human enamel and dentine using a cyclic de– and remineralisation model in vitro. The mineral content expressed in micrometres was determined daily by longitudinal microradiography (LMR) and presented as cumulative mineral loss over 5 days. For erosive demineralisation, all samples were immersed in 0.05 M citric acid (pH 2.3) for 6×10 min/day and stored in a remineralisation solution. Fluoridation measures were performed as follows: group 1: control, no fluoridation; group 2: toothpaste fluoridation 3×5 min/daily (NaF, 0.15% F^–); group 3: toothpaste fluoridation as group 2 and additionally application of a fluoride mouthrinse (Olaflur/SnF₂, 0.025%F^–) 3×5 min/daily and on days 1 and 3 gel fluoridation (Olaflur/NaF; 1.25% F^–) for 1×5 min. After the first experimental day, no significant differences were found between the groups. However, after 5 days the erosive mineral loss values for enamel were 147.5±18.7 µm in the control group, 128.1±15.0 µm in group 2 (p≤0.05) and 116.1±12.4 µm in group 3 (p≤0.001). In dentine, the respective values were 136.7±16.4, 111.8±26.9 (p≤0.001) and 60.3±17.8 (p≤0.001). The intensive fluoridation significantly reduced erosion progression in enamel but had a more pronounced effect on dentine. The results suggest that subjects with erosive lesions should use an intensive fluoridation measure.

Effect of fluoride solutions on the shear bond strength of orthodontic brackets

“…The cariostatic effect occurs due to the formation of a calcium fluoride layer (CaF 2 ) which dissolves and releases ions by pH reduction to prevent that the underlying enamel is reached (11). APF 1.23% has a pH of 3.2-3.5, in which a low concentration of hydrogen dissolves the enamel surface to form CaF 2 .…”

AmF/NaF/SnCl2 solution reduces in situ enamel erosion – profilometry and cross-sectional nanoindentation analysis

“…1,8,10,11,16,23,24 The in situ study design here using two erosive challenges per day (0.65% citric acid, pH 3.6) appears relatively slight but should reflect situations that can occur in patients with incipient erosion (2.7 μm -4.8 μm). [25][26][27] As expected, in the present study, the profilometric analysis showed that the lowest tissue loss was observed in the fluoride-treated group (AmF/NaF/SnCl 2 solution containing 500 ppm F -, 800 ppm Sn 2+ , pH = 4.5) compared to the control group.…”

“…14,16 In vitro and in situ studies show that pretreatment of enamel with tin-containing solutions can protect the enamel surface, inhibiting or reducing the erosive effect of acids through the formation of a superficial layer, containing Sn 2 OHPO 4 , Sn 3 F 3 PO 4 , Ca(SnF 3 ) 2 and CaF 2 -like precipitates, with a low dissolution rate. 1,3,4,12,13,24,32 It is believed that the treatment of the substrate with tin containing fluoride solutions favors the tin incorporation, and perhaps also the fluoride incorporation into the underlying enamel tissue, resulting in a broad structurally modified surface region, rich in tin and resistant to erosive acid challenge 28 . In addition, according to Hjortsjo et al 32 , the mechanism by which metal fluorides inhibitdental erosion is at least partially associated with the presence of HF (hydrofluoric acid) molecules that are capable of penetrating into the enamel and possibly form CaF 2 molecules in the inner enamel substrate.…”

“…In situations where the aim is to limit the damage identified early, even if the individual is still asymptomatic, as well as for caries, fluoride is a widely-used strategy used to prevent dental erosion. However, its efficacy is still the object of controversy 1,2 , because little is known about the mechanism of action of fluoride on the prevention and/or control of dental erosion; erosive challenges are much more aggressive than cariogenic challenges and only a thin surface layer, partially demineralized, remains to provide structure for remineralization of eroded surface. 1 Successful results on the reduction of dental demineralization by erosive acids have been shown with polyvalent metal ion-containing products, such as stannous, in several in vitro studies 3,4,5,6,7 and confirmed by other in situ studies.…”

“…However, its efficacy is still the object of controversy 1,2 , because little is known about the mechanism of action of fluoride on the prevention and/or control of dental erosion; erosive challenges are much more aggressive than cariogenic challenges and only a thin surface layer, partially demineralized, remains to provide structure for remineralization of eroded surface. 1 Successful results on the reduction of dental demineralization by erosive acids have been shown with polyvalent metal ion-containing products, such as stannous, in several in vitro studies 3,4,5,6,7 and confirmed by other in situ studies. 8,9,10,11 Authors have reported the use of tin-ion in different presentation, such as solutions, toothpastes, gels and varnishes.…”