Dental erosion is prevalent in children and adults globally, with some researchers finding it present in approximately half of adolescents (Al-Dlaigan et al. 2001; McGuire et al. 2009). Estimated prevalence in some locations can be found in Figure 6.
Figure 6. Estimated prevalence of dental erosion among youth
(Nayak et al. 2010; Hou et al. 2009; Wiegand et al. 2006; Deery et al. 2000; Kazoullis et al. 2007; Wang et al. 2010; Manaf et al. 2012; Mantonanaki et al. 2013; Nahás et al. 2011)
Dental erosion occurs primarily due to the excessive presence of non-bacterial extrinsic acids (especially dietary acids such as acidic drinks), as well as intrinsic gastric acid associated with gastroesophageal reflux disease (GERD) and bulimia (Moazzez et al. 2004; Bouqot & Seime 1997). Dental erosion involves the demineralization and softening of the tooth surface, which once softened, is highly susceptible to abrasion and attrition (Figure 7). A diagnosis of erosion can be made based on the pattern of surface loss of enamel and/or dentin (Figures 8a,b)
Figure 7. Demineralization associated with dental erosion
Figure 8a. Generalized erosion
Courtesy of Prof. Ian Meyers
Figure 8b. Severe palatal erosion and loss of tooth structure.
Courtesy of Prof. Ian Meyers
Unlike dental caries where demineralization is initially mainly subsurface and is also reversible in its early stages, dental erosion involves repeated demineralization of the surface with subsequent surface loss and this process is irreversible (Figures 9a, b).
Figure 9a. Dental caries process
Enamel crystals are weakened, but remain structurally intact. The early caries process is reversible
Figure 9b. Dental erosion process
Enamel crystals are damaged structurally from the surface down into the tooth. The erosive process is irreversible
The deposition of stannous ions at the tooth surface helps protect it against dental erosion (Faller & Eversole 2014):
A recent in vitro study compared the ability of various fluoride toothpastes to form a protective barrier layer (Faller & Eversole 2014). The toothpastes evaluated included 1,100 ppm stannous fluoride, 1,100 ppm sodium fluoride, 1,000 ppm sodium monofluorophosphate and 1,400 ppm amine fluoride. The study involved exposing etched samples to toothpaste-saliva slurries, rinsing them, and then exposing them to 2% alizarin Red-S. Dye deposition was assessed using a 5-point scale, with 0 being no dye deposition and 4 being complete dye coverage. A low score indicates a barrier layer is present, preventing the deposition of dye. The stannous fluoride toothpaste had the lowest score, 0.25. At the other extreme, amine fluoride resulted in a score of 3.7 (Figure 10). This in vitro test confirmed the ability of stannous to form a protective barrier layer, and demonstrated that stannous fluoride is a preferred fluoride for delivering an enamel protection benefit via a barrier mechanism to erosive acids.
Figure 10. Degree of dye deposition on enamel samples following exposure to toothpaste slurry followed by dye
* Average deposition of stain (based on the 5-point scale)
Other in vitro tests have also demonstrated the superior protective effect of stannous fluoride-treated enamel slabs in comparison to sodium fluoride-treated enamel slabs during an erosive challenge (Figure 11; Faller 2012). Exposure to dietary acid in an erosion cycling model resulted in surface demineralization and surface loss for the slabs treated with sodium fluoride toothpaste slurry while minimal demineralization or surface loss occurred with the slabs treated with stannous fluoride toothpaste slurry.
Figure 11. Stannous fluoride vs. sodium fluoride in in vitro treated enamel slabs
The following study summaries represent a sample of research demonstrating the benefits of stabilized stannous fluoride dentifrice for protection against acid erosion.
In addition, an independent consensus statement by the European Federation of Conservative Dentistry found “oral hygiene products, such as toothpastes or mouth rinses, containing stannous fluoride or stannous chloride have the potential to slow the progression of erosive tooth wear.” The authors found data are limited for other products. (Carvalho et al. 2015)
Reference: Hooper SM, Newcombe RG, Faller R, Eversole S, Addy M, West NX. J Dent. 2007 Jun;35(6):476-81. Epub 2007 Feb 27
The results of this study provide further support for tooth brushing before meals. Results further suggest the stannous fluoride dentifrice could be used to provide significant erosion protection in susceptible patients versus that provided by conventional fluoride products.
Consumption of soft drinks, fruit juices and sport drinks has increased dramatically in the UK, the US, and elsewhere. Previous studies have demonstrated the erosive nature of these acidic soft drinks. The objective of this study was to determine the protective effects of experimental stannous fluoride-based toothpaste, containing sodium hexametaphosphate, against an erosive challenge (orange juice) on tooth enamel.
There was significantly more erosive damage on the specimens exposed to the benchmark toothpaste (NaF) and negative control (water) compared to the test stannous fluoride toothpaste in both the in situ (Figure 1) and in vitro (Figure 2) studies.
Figure 1. In Situ Loss of Material*
Figure 2. In Vitro Loss of Material*
* mean value based on duplicate determinations of two enamel specimens
Reference: Faller RV, Eversole SL, Tzeghai G. J Dent Res. 2009;88 (Spec Iss A): Abstract 3368.
Dentifrices with RDA< 250 are considered safe for daily use. Some researchers believe products with low RDA may be less aggressive on erosively softened enamel. Others believe that once softened, erosively challenged enamel will be removed by any friction, even by the tongue. This research was conducted to determine the primary driver of enamel protection benefits: is abrasivity or fluoride (F) salt the more important factor?
Figure Average % Reduction in Total Mineral Loss*
* (vs. NaF product)
Reference: N. West, T. He, Hellin N, et al. J Dent Res 2017;96 (Spec Iss A): Abstract 0610
Crest® PRO-HEALTH™ Advanced dentifrice (SnF2) demonstrated significantly greater protection against dental erosion relative to the Colgate Total (triclosan/copolymer) dentifrice in a 10-day in situ clinical study. At Day 10, the SnF2 dentifrice demonstrated 93.5% lower enamel loss than the triclosan/copolymer dentifrice with median loss of 0.097 μm and 1.495 μm, respectively, which wasstatistically significant (P<0.0001). See Figure. Both products were well tolerated.
Figure. Treatment comparison at Day 10: Median Change in Enamel (μm)
* Treatment difference at Day 10 was statistically significant. P<0.0001 N=34.
To compare the enamel protection efficacy (loss of tooth enamel due to erosion as measured by surfometry) of a marketed stannous fluoride dentifrice and a marketed triclosan/copolymer sodium fluoride dentifrice in a 10-day in situ erosion model.
Reference: XY Zhao1, T He2, Y He2, C Cheng2, HJ Chen2.
1Fourth Military Medical University, Xi’an, PR China; 2Procter & Gamble.
The experimental stabilized stannous fluoride (SnF2) dentifrice provided 26.9% greater erosion protection relative to the control dentifrice at Day 10 (P<0.03).
Figure 1. Enamel loss at Day 10
*Lussi A. Int Dent J 2014; 64 (Suppl 1): 2-3.
To compare the enamel protection efficacy of a stabilized stannous fluoride dentifrice and a marketed control dentifrice in a 10-day in situ erosion model.
Stabilized SnF2 dentifrice has been shown to provide significantly greater protection from acid erosion compared to other types of fluoride dentifrice.* In this trial, a novel stabilized stannous fluoride dentifrice showed a significant anti-erosion benefit over a sodium fluoride/potassium nitrate dentifrice which is marketed for protecting enamel against acid erosion. Dental professionals should consider recommending this SnF2 dentifrice for its high level of protection against acid erosion as well as its benefits for reduction of gingivitis and plaque.
*Lussi A. Int Dent J 2014; 64 (Suppl 1): 2-3.