The Protective Effect of TiF₄, SnF₂ and NaF on Erosion of Enamel by Hydrochloric Acid in vitro Measured by White Light Interferometry

Abstract

The purpose of this in vitro study was to compare the protective effect of TiF₄, SnF₂ and NaF (all 0.5 M F) on the development of erosion-like lesions in human dental enamel. Four enamel specimens from each of 6 extracted molars were polished and embedded in epoxy resin. The enamel surfaces of 3 specimens from each tooth were treated with the different fluoride solutions for 2 min. Following fluoride treatments, the specimens were immersed in 0.01 M HCl (pH 2.0), for 2, 4 and 6 min in order to mimic a gastric reflux situation. One specimen from each tooth was used as a control and was only exposed to acid. The etching depths (in micrometres) after 6 min were: TiF₄0.8 (SD 0.8), SnF₂ 3.5 (SD 0.7), NaF 5.3 (SD 0.4), and 7.0 (SD 0.3) for the control specimens. Compared to the control, TiF₄ protected the enamel surface from acid attack almost completely (88%), while SnF₂ reduced the etch depth after 6 min by 50% and NaF by 25%.

Effect of foods and drinks on primary tooth enamel after erosive challenge with hydrochloric acid

“…10 Apart from an acidic diet, erosion is also caused by frequent contact of the oral cavity 6,19 with HCl, being commonly observed in paediatric patients with gastro-oesophageal reflux. 5 The proposed protocol to simulate an episode of gastro-oesophageal reflux was adapted from the in vitro model of Hove et al 19 HCl, used in intrinsic erosion models, 20 is a strong acid, 21 which, in the presence of water, dissociates completely into hydrogen ions and chloride ions, removing the mineral surface. 22 Short-term acid exposures cause surface changes observed before the loss of tooth structure.…”

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

“…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.…”

“…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.…”

“…12 Apart from the deposition of CaF 2 -like globules on dental surface, which seem to be relatively less susceptible to acid dissolution, the reaction between tin and enamel hydroxyapatite can result in the formation of Sn-containing salts [(Sn 2 OHPO 4 , Sn 3 F 3 PO 4 , Ca(SnF 3 ) 2 ]. 3,13,14 These tin deposits and its possible incorporation into the enamel surface form a covering "protective" stable layer, which results in a more acid resistant enamel surface. 3,4 In a previous in vitro study, the use of AmF/NaF/SnCl 2 solution promoted significant protection against enamel loss.…”

“…3,13,14 These tin deposits and its possible incorporation into the enamel surface form a covering "protective" stable layer, which results in a more acid resistant enamel surface. 3,4 In a previous in vitro study, the use of AmF/NaF/SnCl 2 solution promoted significant protection against enamel loss. 14, 15 Similarly, in an in situ model, the samples treated with AmF/NaF/SnCl 2 solution had a 67% reduction in enamel loss compared to the placebo/control group.…”