Anti-erosive properties of solutions containing fluoride and different film-forming agents
Introduction
Epidemiological studies have demonstrated that erosive tooth wear (ETW) is a common dental condition worldwide.1 During the initial stages, the signs and symptoms of ETW are seldom perceived by the patients. In advanced cases, however, pain as result of dentine exposure, as well as loss of tooth anatomy and vertical dimension can become serious consequences.2, 3 Considering the irreversible nature of this condition, early diagnosis and management by implementation of preventive and therapeutic measures are of utmost importance. In this regard, regular application of fluoride (F) products intended to reduce the solubility of the tooth surfaces has been one of the most recommended approaches.4, 5 However, previous studies show a large variation in efficacy, which among other factors seems to be strongly related to the type of F compound tested.6, 7, 8
The formation of calcium fluoride (CaF2)-like deposits on the tooth surfaces is assumed to be the main mechanism of protection against dental erosion provided by conventional F compounds, such as sodium fluoride (NaF) and amine fluoride (AmF).8 These deposits can act either as a physical barrier against erosive acids or as a mineral reservoir for remineralization.9 Nevertheless, comparative studies showed that some F compounds with polyvalent metal cations, such as stannous fluoride (SnF2) have improved efficacy.6, 8, 10 Besides the formation of CaF2, the stannous ion (Sn) can interact with the tooth surfaces forming a Sn-rich coating, which may also be relevant for erosion prevention.6, 8, 11 Previous in vitro and in situ studies on solutions containing F and Sn (F as NaF and AmF; Sn as SnCl2 – stannous chloride) seem to suggest an additive effect between these ions.12, 13
Organic and inorganic polymers have also been evaluated for their ability to reduce dental erosion. Some polymers have been tested as active ingredients of rinse solutions or toothpastes5, 14, 15, 16 and also as additives in acidic beverages.17, 18, 19, 20, 21 The tested polymers have shown the potential to reduce erosion progression due to their ability to adsorb to the dental surfaces, leading to the formation of a protective film. Promising results were obtained especially for milk casein,15 chitosan,5 linear sodium polyphosphate (LPP),17, 18, 21 and a combination of carboxymethylcellulose, xantham gum and copovidone.14 In addition, previous studies have demonstrated that several of these polymers can interact positively with fluoride compounds, thereby enhancing its protective effects.5, 15, 22
There is, however, considerably more scope for further research as (a) none of the tested film-forming agents or combinations thereof have been shown to completely inhibit erosion, and (b) research to determine additive or synergistic anti-erosive properties of combinations of actives has been very limited. Therefore, the present study was concerned with the investigation of the anti-erosive properties of some of the above mentioned film-forming agents, and especially in their interaction with fluoride. The pH-stat method (Phase 1) was used as a first screening tool. The most promising test solutions were then further evaluated using two in vitro erosion cycling models of different aggressiveness (Phase 2a and 2b). Our test hypothesis was that the additives, alone or in combination with F would present improved anti-erosive potential, when evaluated under different erosive conditions.
Section snippets
Experimental design
This study was carried out in 2 phases. In Phase 1, hydroxyapatite crystals were exposed to solutions containing F (as NaF), phosphate polymers, proteins and Sn (as SnCl2); as well as some of their combinations. Deionized water was used as negative control (C). The crystals were then tested in triplicate with the pH-stat as a screening method, using a standard citric acid solution (0.3%, pH = 3.8). The agents with the most promising results in Phase 1 (F, LPP, Sn), some of their combinations and
Phase 1
Table 1 shows the mean values of HAPc dissolution obtained in the pH-stat method. The negative control (C) resulted in the highest HAPc dissolution. In general, the higher concentration of the polymers (20 g/l) presented slightly less HAPc dissolution than the lower ones (2 g/l). Pre-treatments with F, LPP (at 20 g/l) and Sn reduced HAPc dissolution approximately 60% in comparison to C. SC, BSA, STP and PP demonstrated less ability to reduce HA dissolution, with 22%, 17%, 15% and 14% of reduction
Phase 1
In the screening phase, F, LPP (20 g/l) and Sn provided the highest reduction of HAPc dissolution, being therefore selected for Phase 2. SC, BSA, PP and STP had no more than 22% of reduction. The magnitude of HAPc dissolution observed for SC at the higher concentration was similar to that reported in a previous study, where a solution containing 5 g/l of whole casein was able to reduce enamel loss by about 20%.15 However, in that study, a prolonged exposure time to the solution was performed (10
Acknowledgment
The authors wish to thank Adam Kelly, research technician at the OHRI-Indiana University School of Dentistry, for the technical support.
References (45)
- et al.
Efficacy of the stannous ion and a biopolymer in toothpastes on enamel erosion/abrasion
Journal of Dentistry
(2012) - et al.
The efficacy of a highly concentrated fluoride dentifrice on bovine enamel subjected to erosion and abrasion
Journal of American Dental Association
(2008) - et al.
Effect of sodium, amine and stannous fluoride at the same concentration and different pH on in vitro erosion
Journal of Dentistry
(2009) - et al.
Studies on a novel combination polymer system: in vitro erosion prevention and promotion of fluoride uptake in human enamel
Journal of Dentistry
(2010) - et al.
A clinical study in situ to assess the effect of a food approved polymer on the erosion potential of drinks
Journal of Dentistry
(2007) - et al.
Pectin, alginate and gum Arabic polymers reduce citric acid erosion effects on human enamel
Dental Materials
(2010) - et al.
In vitro evaluation of the erosive potential of orange juice modified by food additives in enamel and dentine
Journal of Dentistry
(2011) - et al.
In situ remineralisation of eroded enamel lesions by NaF rinses
Archives of Oral Biology
(2012) Bioactive properties of milk proteins with particular focus on anticariogenesis
Journal of Nutrition
(2004)- et al.
Electrokinetic properties of hydroxyapatite under flotation conditions
Journal of Colloidal Interface Science
(2010)
Sodium fluoride effect on erosion–abrasion under hyposalivatory simulating conditions
Archives of Oral Biology
Effect of low-fluoride toothpastes combined with hexametaphosphate on in vitro enamel demineralization
Journal of Dentistry
Prevalence, incidence and distribution of erosion
Monographs in Oral Science
Dental erosion – an overview with emphasis on chemical and histopathological aspects
Caries Research
Is dental erosion really a problem?
Advances in Dental Research
Insights into preventive measures for dental erosion
Journal of Applied Oral Science
Effect of fluoride compounds on enamel erosion in vitro: a comparison of amine, sodium and stannous fluoride
Caries Research
Fluoride in dental erosion
Monographs in Oral Science
The protective effect of TiF4, SnF2 and NaF against erosion-like lesions in situ
Caries Research
The reaction of stannous fluoride and hydroxyapatite
Journal of Dental Research
Tin and fluoride as anti-erosive agents in enamel and dentine in vitro
Acta Odontologica Scandinavia
Efficacy of a tin/fluoride rinse: a randomized in situ trial on erosion
Journal of Dental Research
Cited by (43)
Characteristics of tin-containing fluoride toothpastes related to erosive tooth wear protection
2024, Journal of DentistryProtective effect of anti-erosive solutions enhanced by an aminomethacrylate copolymer
2021, Journal of DentistryCitation Excerpt :Recently, the anti-erosive effect of mouthrinses [17–20], toothpastes [21,22] and acidic beverages [23–25] containing polymers has been investigated. Solutions containing some polymers can also enhance the protective potential of fluorides [17,18]. However, a wide range of polymers is available to be tested, being necessary to consider their possible chemical interactions with the hydroxyapatite and the acquired salivary pellicle, in order to produce an effective polymeric film on the tooth surface.
Interplay between different manual toothbrushes and brushing loads on erosive tooth wear
2021, Journal of DentistryHandbook of Fillers
2021, Handbook of FillersRandomized in situ trial on the efficacy of Carbopol in enhancing fluoride / stannous anti-erosive properties
2020, Journal of DentistryCitation Excerpt :In recent years, the erosion-inhibiting effect of metal-containing fluoride compounds, such as stannous fluoride (SnF2) or the combination between fluoride and stannous, has gained increasing attention, as they were proven to be more effective in reducing enamel erosion than sodium or amine fluoride [1,2]. In addition to the formation of the CaF2-like compounds, stannous can interact with the dental surfaces forming a modified Sn-enriched layer, which is more acid resistant [2–5]. Nevertheless, despite of these positive results, a complete reduction in erosion has yet to be achieved.