Randomised in situ trial on the effect of milk and CPP-ACP on dental erosion

The role of calcium in the prevention of erosive tooth wear: a systematic review and meta-analysis

OBJECTIVES

The loss of hard dental tissue due to recurrent acid challenges and mechanical stresses without bacterial involvement is known as erosive tooth wear (ETW). Many studies in the literature have concentrated on variables that may affect the ETW process and prevent its occurrence or reduce its advancement. However, to date, no previous systematic review has evaluated the role of calcium in preventing ETW. Therefore, the purpose of the present systematic review was to review and critically appraise the scientific evidence regarding the role of calcium formulations in the prevention of ETW.

METHODS

The review protocol was registered in the PROSPERO international prospective register of systematic reviews (Ref: CRD42021229819). A literature search was conducted in electronic databases to identify in situ randomized controlled trials evaluating the prevention of ETW following the application of calcium formulations. The outcomes studied included mean enamel loss, surface microhardness, surface roughness, mean erosion/softening depth, mineral loss/precipitation and remineralization. Study characteristics and outcomes of included studies were summarized. Cochrane's risk-of-bias tool 2.0 was used to assess the quality of eligible studies, and meta-analysis using a random effects model was performed.

RESULTS

The search retrieved 869 studies of which 21 were considered eligible. Regarding the results of the quality assessment for potential risk of bias in all included studies, overall, 5 studies were considered as being at low risk, another 12 at unclear risk and 4 at high risk of bias. The findings of the studies showed that the addition of calcium in juice drinks led to reduced enamel loss, with blackcurrant juice presenting 2.6 times statistically significant less enamel loss compared to orange juice (p = 0.0001, I2 = 89%). No statistically significant difference in mean surface microhardness of eroded enamel was recorded between chewing gum with or without casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (p = 0.31, I2 = 71%). Contradictory were the results regarding the effect of milk and CPP-ACP pastes on prevention of ETW.

CONCLUSIONS

Calcium formulations play an important role in ETW prevention, mainly through their addition to acidic drinks.

Film-Forming Polymers for Tooth Erosion Prevention

Different agents have been proposed to prevent the progression of acid induced dental substance losses, which are called erosive tooth wear (ETW), such as fluorides, calcium, and phosphate-based products; however, there is a need for a further increase in efficacy. Recently, the ability of polymers to interact with the tooth surface, forming acid resistant films, has come into the focus of research; nevertheless, there is still the need for a better understanding of their mode of action. Thus, this article provides an overview of the chemical structure of polymers, their mode of action, as well as the effect of their incorporation into oral care products, acid beverages, and antacid formulations, targeting the prevention of ETW. Recent evidence indicates that this may be a promising approach, however, additional studies are needed to confirm their efficacy under more relevant clinical conditions that consider salivary parameters such as flow rate, composition, and clearance. The standardization of methodological procedures such as acid challenge, treatment duration, and combination with fluorides is necessary to allow further comparisons between studies. In conclusion, film-forming polymers may be a promising cost-effective approach to prevent and control erosive demineralization of the dental hard tissue.

Topical Agents for Nonrestorative Management of Dental Erosion: A Narrative Review

A nonrestorative approach to the management of dental erosion is the foremost option: controlling dental erosion. The objectives of this study are to provide an overview and to summarise the effects and properties of topical anti-erosive agents as a nonrestorative treatment of dental erosion. A literature search was conducted on five databases of peer-reviewed literature—Cochrane Library, EMBASE, PubMed, Scopus and Web of Science—to recruit articles published between 1 January 2000 and 31 December 2021. The literature search identified 812 studies; 95 studies were included. Topical anti-erosive agents can be broadly categorised as fluorides, calcium phosphate-based agents, organic compounds and other anti-erosive agents. In the presence of saliva, fluorides promote the formation of fluorapatite on teeth through remineralisation. Calcium phosphate-based agents supply the necessary minerals that are lost due to the acid challenge of erosion. Some organic compounds and other anti-erosive agents prevent or control dental erosion by forming a protective layer on the tooth surface, by modifying salivary pellicle or by inhibiting the proteolytic activity of dentine collagenases. Topical anti-erosive agents are promising in managing dental erosion. However, current evidence shows inconsistent or limited results for supporting the use of these agents in clinical settings.

A Scopus-Based Bibliometric Analysis of Global Research Contributions on Milk Fluoridation

Fluoridated-milk schemes have been developed and implemented in many countries to prevent dental caries. This study aimed to evaluate the impact/influence of scientific publications, researchers, and institutions conducting research on milk fluoridation; to explore the international and inter-institutional collaboration and illustrate scientific output trends; and to pinpoint research hotspots in milk fluoridation research. This bibliometric analysis of original research articles on milk fluoridation includes all of the original articles published in peer-reviewed journals systematically extracted from the SCOPUS database. In total, 108 articles were included in this study, with a total of 11,789 citations. A majority (67.6%) of these articles were in the subject area of ‘dentistry’, 22.2% externally funded, 14.8% published in the journal, Caries Research, 7.4% authored/co-authored by Twetman S, 6.5% by authors from Universidad de Chile, and the UK had the highest output (24.1%). The network visualizations showed that those countries with current/past histories of implemented milk fluoridation programs were interconnected on the network visualization map, and they were predominantly the hotspots for original research on milk fluoridation. This study also identified inequalities in research outputs on the topic. With the current enormous global burden of dental caries in children, particularly in low- and middle-income countries, there is an urgent need for greater and more equitable funding of milk fluoridation research globally.

Fluoridated milk enhances the mineral density of artificial proximal carious lesions in situ

OBJECTIVE

To compare the mineral density (MD) of non-fluoridated-milk (non-F-milk), fluoridated-milk (F-milk), adjunctive to 1000-ppm-fluoride dentifrice (FD), and 1000-ppm-FD alone of proximal artificial enamel carious lesions (AECL) in high caries-risk patients.

MATERIALS AND METHODS

This double-blind, cross-over in situ study comprised seven high caries-risk volunteers. Orthodontic brackets with one slab of AECL were fixed randomly to each volunteer per phase. The study comprised three experimental periods with a 7-d wash-out period using FD between sessions; (1) A four-week tooth brushing with FD 2×/day by all subjects as a control. The participants were then randomly allocated to (2) drinking 2.5-ppm-F-milk 1×/day or (3) non-F-milk 1×/day, adjunctive to tooth-brushing with FD for 4-weeks. The subjects crossed over from each type of milk and continued the same protocol for another four weeks. After each phase, the MD of each specimen was analyzed using micro-computed tomography (Micro-CT).

RESULTS

The baseline MD was not significantly differences (p = .653). When brushing with FD and drinking F-milk, the MD gain was significantly higher (11.68 ± 2.89%) compared with brushing with FD and drinking non-F-milk (4.59 ± 1.78%) (p = .003) or brushing with FD alone (5.30 ± 2.10%) (p = .003).

CONCLUSIONS

F-milk adjunctive to FD significantly increased MD gain compared with non-F-milk + FD or FD alone.

An ICT-based fluorescence enhancement probe for detection of Sn2+ in cancer cells

Development of a novel fluorescence enhancement probe for detection of Sn²⁺ in organisms, with high selectivity and sensitivity, is of great interest but remains a great challenge. Herein, an ICT-based fluorescence probe TPPB was rationally developed to act as an ‘enhancement’ luminescent and “naked-eye” indicator for Sn²⁺ detection. Importantly, spectroscopic studies indicated that TPPB was a fluorescence enhancement sensor for Sn²⁺ with rapid response, low detection limit (0.116 μM) and excellent binding constant (1.6 × 10⁴ M⁻¹). The mechanism of TPPB response to Sn²⁺ was further proved by ¹H NMR titration, and enhancement calculations. Furthermore, TPPB is applied as a fluorescence probe for imaging in Hela cells, indicated that it can be potentially applied for Sn²⁺ sensing in biological fields.

Development of a novel fluorescence enhancement probe for detection of Sn²⁺ in organisms, with high selectivity and sensitivity, is of great interest but remains a great challenge.

Casein phosphopeptide combined with fluoride enhances the inhibitory effect on initial adhesion of Streptococcus mutans to the saliva-coated hydroxyapatite disc

Background

Recent preventive strategies for dental caries focus on targeting the mechanisms underlying biofilm formation, including the inhibition of bacterial adhesion. A promising approach to prevent bacterial adhesion is to modify the composition of acquired salivary pellicle. This in vitro study investigated the effect and possible underlying mechanism of pellicle modification by casein phosphopeptide (CPP) on Streptococcus mutans (S. mutans) initial adhesion, and the impact of fluoride on the efficacy of CPP.

Methods

The salivary pellicle-coated hydroxyapatite (s-HA) discs were treated with phosphate buffered saline (negative control), heat-inactivated 2.5% CPP (heat-inactivated CPP), 2.5% CPP (CPP) or 2.5% CPP supplemented with 900 ppm fluoride (CPP + F). After cultivation of S. mutans for 30 min and 2 h, the adherent bacteria were visualized by scanning electron microscopy (SEM) and quantitatively evaluated using the plate count method. Confocal laser scanning microscopy (CLSM) was used to evaluate the proportions of total and dead S. mutans. The concentrations of total, free, and bound calcium and fluoride in the CPP and fluoride-doped CPP solutions were determined. The water contact angle and zeta potential of s-HA with and without modification were measured. The data were statistically analyzed using one-way ANOVA followed by a Turkey post hoc multiple comparison test.

Results

Compared to the negative control group, the amount of adherent S. mutans significantly reduced in the CPP and CPP + F groups, and was lowest in the CPP + F group. CLSM analysis showed that there was no statistically significant difference in the proportion of dead S. mutans between the four groups. Water contact angle and zeta potential of s-HA surface significantly decreased in the CPP and CPP + F groups as compared to the negative control group, and both were lowest in the CPP + F group.

Conclusions

Pellicle modification by CPP inhibited S. mutans initial adhesion to s-HA, possibly by reducing hydrophobicity and negative charge of the s-HA surface, and incorporating fluoride into CPP further enhanced the anti-adhesion effect.

Prevention of Enamel Softening by Rinsing with a Calcium Solution before Dental Erosion

OBJECTIVES

This in situ study aimed to evaluate whether rinsing with a calcium-containing solution prior to an erosive attack reduces the softening of enamel.

MATERIALS AND METHODS

A total of 240 bovine enamel samples with determined baseline surface microhardness (KHN) were allocated to 5 runs in which each of the 12 volunteers performed the following experiment: 4 enamel samples were inserted in a custom-made intraoral appliance and carried in the mouth (upper jaw) for 30 min before each volunteer either rinsed his mouth for 60 s with a fluoride- and stannous ion-containing dental erosion protection mouth rinse as positive control (run 1), milk (run 2), a solution prepared from a 500-mg calcium effervescent tablet dissolved in 100 mL (run 3) or 200 mL (run 4) water, or did not perform any rinsing with a test solution before the erosive attack (run 5, negative control). To simulate the erosive attack, volunteers rinsed their mouth with a commercial soft drink (Sprite Zero) for 60 s and afterwards with water to stop the erosive process. Finally, surface microhardness was measured again and hardness loss (ΔKHN) calculated. A mixed effect model was fitted to the data set to investigate whether the different runs showed differences with respect to ΔKHN.

RESULTS

No significant difference in softening of enamel (mean of ΔKHN; lower confidence level/upper confidence level) was observed between the negative control run 5 (50.7; 60.8/40.6), run 2 (50.7; 60.8/40.6), run 3 (38.7; 48.8/28.6) and run 4 (40.7; 50.8/30.6) (p > 0.05, respectively). Enamel softening in the positive control run 1 (25.4; 35.6/15.3) was significantly lower compared to the softening in run 5 (p < 0.001). No significant difference was observed between run 1 and run 3 (p = 0.09).

CONCLUSION

Other than the fluoride- and stannous ion-containing dental erosion protection mouth rinse, none of the investigated calcium-containing solutions is able to significantly reduce erosion-induced softening of enamel.

Fe–Ni metal–organic frameworks with prominent peroxidase-like activity for the colorimetric detection of Sn2+ ions

The synthesized Fe–Ni-MOF could oxidize TMB to produce oxTMB with blue color. The presence of Sn²⁺ ions could make the oxTMB color lighter, hence colorimetric detection of Sn²⁺ ions is realized.

Characterization of the in situ pellicle ultrastructure formed under the influence of bovine milk and milk protein isolates

OBJECTIVES

The present study aimed to investigate if bovine milk or milk protein isolates, respectively, alter the ultrastructure of thein situ pellicle and might therefore have an influence on oral health.

METHODS

In situ pellicle samples were formed on bovine enamel slabs exposed in the oral cavity of three subjects for 6, 30, 60 or 120 min. After 3 min of pellicle formation, mouthrinses were performed for 3 min with (non-)homogenized UHT- or fresh milk (0.3% or 3.8% fat), 30% UHT-treated cream or different types of casein- or milk protein isolates containing preparations. The specimens were removed after the exposure times and transmission electron microscopy (TEM) was performed. Native pellicle samples served as controls.

RESULTS

Topical ultrastructural pellicle modifications were detected after mouthrinses with all types of homogenized UHT- or fresh milk and after the application of a 3% native casein micelles containing experimental solution. Atypical globular protein structures, identified as casein micelles, were temporarily adsorbed onto the pellicle. They were closely associated with lipid droplets. Furthermore, the mouthrinses occasionally affected the morphology of salivary bacteria. However, no notable ultrastructural alterations remained after 120 min of pellicle formation.

CONCLUSION

For the first time, bovine milk- and micellar casein-induced pellicle modifications were revealed by TEM. The adsorption of micellar casein is possibly due to its molecular interactions.

CLINICAL SIGNIFICANCE

Bovine milk or micellar caseins provide some potential for the development of preventive strategies against bacterial biofilm formation or erosive processes at the tooth surface.

Overview of Calcium Phosphates used in Biomimetic Oral Care

Background:

The use of biomimetic agents is an emerging field in modern oral care. Promising biomimetic substances for such applications are calcium phosphates, because their chemical composition is very similar to that of the mineral phase in human teeth, especially of natural enamel. Examples for their application include the remineralization of early caries lesions and repair of small enamel defects.

Objective:

This review provides an interdisciplinary view on calcium phosphates and their applications in biomimetic oral care. The aim of this work is to give an overview of in vivo and in situ studies comparing several calcium phosphates in preventive dentistry that can be used as a knowledge base for the development of innovative alternative oral care concepts.

Methods:

Books, reviews, and original research papers with a focus on in vivo and in situ studies were included. The databases PubMed^® and SciFinder^® were used for literature search. Calcium phosphates that are frequently utilized in oral care products are covered in this review and were used as search terms alone and together with the following key words: in vivo, in situ, caries, clinical study, and remineralization. From 13,470 studies found, 35 studies complied with the inclusion criteria and were used for this review.

Results:

Published in vivo and in situ studies demonstrate calcium phosphates’ potential in enamel remineralization. However, more studies are needed to further substantiate existing results and to extend and refine the application of calcium phosphates in modern oral care.

Conclusion:

Calcium phosphates represent an innovative biomimetic approach for daily oral care because of their high similarity to natural enamel that will broaden the range of future treatments in preventive dentistry.

In situ effect of Tooth Mousse containing CPP-ACP on human enamel subjected to in vivo acid attacks

OBJECTIVE

This in situ study aimed to evaluate the protective effect of Tooth Mousse (GC) containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on human enamel erosion and to compare the difference in erosion between the anteriorly and posteriorly positioned human enamel.

METHODS

This study used a 2-treatment (7 days each) crossover design with 12 healthy volunteers wearing intraoral appliances. Each appliance contained 4 human enamel specimens positioned on the buccal surfaces of the volunteers' maxillary central incisors and first molars. The specimens were intraorally treated withTooth Mousse (CPP-ACP group) or deionized water (control group) for 3 min and then exposed to in vivo acid attacks by rinsing with 150 ml of a cola drink (4 × 5 min/day). The surface microhardness (SMH) of the specimens was measured and used to calculate the percentage of SMH loss (%SMH_l). Erosion effect on enamel was also investigated by scanning electron microscopy (n = 4) at the end of study. The data were statistically analysed using two-way analysis of variance (ANOVA) and Tukey's test at a level of P < 0.05.

RESULTS

A significant decrease in %SMH_l was observed for the specimens of CPP-ACP group compared to that for the controls (P = 0.007). The specimens positioned posteriorly exhibited a significantly lower %SMH_l than those positioned anteriorly (P = 0.033). Samples of CPP-ACP group showed fewer etching patterns than those of the control group.

CONCLUSIONS

In this in situ model, application of Tooth Mousse containing CPP-ACP before erosion reduced the %SMH_l of human enamel. Enamel located in different positions showed different patterns of erosion.

CLINICAL SIGNIFICANCE

Application of Tooth Mousse containing CPP-ACP could be considered as a suitable preventive strategy against enamel erosion. ClinicalTrials.gov Identifier: NCT03426150.

Application of the Self- Assembling Peptide P11-4 for Prevention of Acidic Erosion

The aim of this study was to use ultrasonography to evaluate the effect of the self-assembling peptide P11-4 on acid erosion prevention. Curodont Repair (CR), which includes peptide P11-4, was used. Rectangular prisms of bovine enamel (4×1×1 mm) were immersed in pure orange juice for a period of 5 minutes six times per day for 28 days. These samples were divided into four groups of six specimens each and treated differently for an additional period of 28 days: 1) baseline group specimens were stored in artificial saliva; 2) CR group specimens were exposed to curodont without acid challenge; 3) NCRA (no curodont+acid challenge) specimens were treated with orange juice without curodont exposure; and 4) CRA (CR+acid challenge) specimens were treated with curodont before treatment with orange juice. The propagation time of longitudinal ultrasonic velocity (UV) was measured. Ultrastructural observation of each tested enamel surface was carried out using field-emission scanning electron microscopy (SEM). The UV data were analyzed using two-way analysis of variance with time and treatment as confounding factors. Post hoc pairwise tests among groups were performed using the Tukey honestly significant difference test. The average UV in intact bovine enamel for the baseline group ranged from 4,483 to 4,549 m/s and did not vary significantly within the test period. The average ultrasonic velocity (UV) in all samples decreased after the initial erosion. The UV in NCRA decreased further over time. Increased UVs were found for CR and CRA. For CR and CRA, there was no significant difference in UV at the end of the experiment from the initial value before erosion. In the results of SEM observation, the CR and CRA groups had similar morphologic features in that etching patterns were not clearly due to precipitation between the enamel rods. From the results of this in vitro study, it might be concluded that applying enamel matrix derivatives and self-assembling peptides on erosive lesions can improve remineralization.

Effect of Phosphorylated Chitosan on Dentin Erosion: An in vitro Study

The aim of this study was to evaluate the antierosive effect of phosphorylated chitosan in dentin. Bovine dentin specimens were randomly distributed into the following groups: (1) no treatment (NoTx/negative control), (2) phosphate-buffered saline solution (PBS), (3) AmF/NaF/SnCl2 (positive control), (4) 0.5% chitosan solution (Chi), (5) 0.5% neutral phosphorylated (NP)-Chi, and (6) 0.5% alkaline phosphorylated (AP)-Chi. The specimens were submitted to de-remineralization treatment cycles for 5 days: 0.5% citric acid (2 min), remineralizing solution (30 min), and surface treatment according to assigned groups (2 min, 6×/day). The loss of dentin surface was measured by profilometry. Hardness and modulus of elasticity were measured using a nanoindenter equipped with a Berkovich diamond tip. The dentin surface was analyzed by scanning electron microscopy (SEM). The largest loss of dentin was observed in the No Tx and PBS groups (approx. 25 µm). The group treated with AmF/NaF/SnCl2 showed less loss of dentin (67% reduction vs. NoTx and PBS), followed by the groups treated with NP-Chi and AP-Chi (33% reduction), and Chi (18% reduction). Nanohardness and modulus of elasticity were similar in the NoTx and PBS groups, with a small increase in stiffness in all other groups. SEM revealed that the experimental solution of AP-Chi had a favorable effect on maintaining the integrity of collagen fibrils. AmF/NaF/SnCl2 showed a preserved mineralized collagen surface. Further studies are warranted to explore this nontoxic phosphorylated chitosan polymer as an effective agent in the prevention and treatment of dental erosion.

In situ effect of CPP-ACP chewing gum upon erosive enamel loss

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is able to increase salivary calcium and phosphate levels at an acidic pH. Previous studies demonstrated that a CPP-ACP chewing gum was able to enhance the re-hardening of erosion lesions, but could not diminish enamel hardness loss. Therefore, there is no consensus regarding the effectiveness of CPP-ACP on dental erosion.

Effect of different salivary exposure times on the rehardening of acid-softened enamel

This in situ study assessed the effect of different times of salivary exposure on the rehardening of acid-softened enamel. Bovine enamel blocks were subjected in vitro to a short-term acidic exposure by immersion in 0.05 M (pH 2.5) citric acid for 30 s, resulting in surface softening. Then, 40 selected eroded enamel blocks were randomly assigned to 10 volunteers. Intraoral palatal appliances containing 4 enamel blocks were constructed for each volunteer, who wore the appliance for 12 nonconsecutive hours: initial 30 min, followed by an additional 30, and then by an additional 1 hour. For the last additional 10 hours the appliances were used at night, during the volunteers' sleep. Surface hardness was analyzed in the same blocks at baseline, after erosion and after each period of salivary exposure, enabling percentage of surface hardness recovery calculation (%SHR). The data were tested using repeated measures ANOVA and Tukey's test (α = 0.05). Increasing periods of salivary action promoted a progressive increase in the surface hardness (p < 0.001). However a similar degree of enamel rehardening (p = 0.641) was observed between 2 hours (49.9%) and 12 hours (53.3%) of salivary exposure. Two hours of salivary exposure seems to be appropriate for partial rehardening of the softened enamel surface. The use of the intraoral appliance during sleep did not improve the enamel rehardening after erosion.

In situ Effect of Chewing Gum with and without CPP-ACP on Enamel Surface Hardness Subsequent to ex vivo Acid Challenge

The erosion-protective effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is controversial. This study aimed to investigate the ability of CPP-ACP chewing gum to prevent a single event of erosive demineralization in situ. Bovine enamel blocks (n = 120) were randomly assigned to 3 phases according to the baseline surface hardness: phase I (PI) - chewing gum with CPP-ACP, phase II (PII) - chewing gum without CPP-ACP, and control phase (PIII) - salivary effect without stimulation (no gum). Nineteen volunteers participated in this study during 3 crossover phases of 2 h. In PI and PII, the volunteers wore intraoral palatal appliances for 120 min and chewed a unit of the corresponding chewing gum for the final 30 min. In the control phase the volunteers wore the appliance for 2 h, without chewing gum. Immediately after intraoral use, the appliances were extraorally immersed in a cola drink for 5 min to promote erosive demineralization. The percentage of surface hardness loss was calculated. The data were analyzed by ANOVA models and Tukey's test. Lower enamel hardness loss was found after the use of chewing gum with CPP-ACP (PI: 32.7%) and without CPP-ACP (PII: 33.5%) compared to the salivary effect without stimulation (PIII: 39.8%) (p < 0.05). There was no difference between PI and PII (p > 0.05). The results suggest that the use of chewing gum immediately before an erosive demineralization can diminish enamel hardness loss. However, the presence of CPP-ACP in the chewing gum cannot enhance this protective effect.

Protective Effect of Whole and Fat-Free Fluoridated Milk, Applied before or after Acid Challenge, against Dental Erosion

This study analysed in vitro the effect of milk against dental erosion, considering three factors: the type of milk (bovine whole/fat-free), the presence of different fluoride concentrations and the time of application (before/after erosive challenge). Bovine enamel (n = 15/group) and root dentine (n = 12/group) specimens were submitted to the following treatments: after the first erosive challenge - 0.9% NaCl solution (negative control), whole milk with 0, 2.5, 5.0 and 10.0 ppm F, fat-free milk with 0, 2.5, 5.0 and 10.0 ppm F, and 0.05% NaF solution (positive control); before the first erosive challenge - whole milk with 0, 2.5, 5.0 and 10.0 ppm F, fat-free milk with 0, 2.5, 5.0 and 10.0 ppm F, and 0.05% NaF solution (positive control). Specimens were submitted to demineralisation-remineralisation regimes 4 times/day for 5 days. The response variables were enamel and dentine loss (in micrometres). Data were analysed using Kruskal-Wallis/Dunn's test (p < 0.05). For enamel, whole milk containing 10 ppm F, applied before the erosive challenge, was the most protective treatment, but with no significant difference compared with the same treatment carried out after the erosive challenge. For dentine, whole fluoridated milk (all concentrations, after), fat-free 10 ppm F milk (after, before) and whole milk with or without F (except 2.5 ppm F, all before) significantly reduced dentine erosion. It seems that the presence of fluoride, especially at 10 ppm, is the most important factor in reducing dental erosion.

Supplementation of an orange juice with dietary proteins to prevent enamel and dentin erosion

Protein supplementation may be an alternative to reduce the erosive potential of acidic drinks. The aim of this in vitro study was to evaluate the erosive potential of an orange juice modified by dietary proteins. A commercially available orange juice was added 0.2 g/L casein, 2.0 g/L ovalbumin and their combination. The juice with no additives and a commercially available calcium-modified juice were used as negative and positive controls, respectively. Human enamel and dentin specimens (n=11) were tested in an erosion-remineralization cycling model. Enamel was analyzed by surface microhardness and profilometry, whilst dentin by profilometry only. Statistical analyses were performed using one-way ANOVA followed by Tukey's test (p<0.05). Calcium-modified juice showed the lowest erosive potential for both analyses (p<0.05). For enamel, the protein-added groups did not differ from each other (p>0.05) and showed significantly lower enamel loss compared to negative control (p<0.05). Regarding surface microhardness, casein showed the highest values compared to negative control (p<0.05). For dentin, none of the protein-added groups showed lower values of surface loss compared to negative control (p>0.05). In conclusion, for enamel the protein-modified orange juices presented reduced erosion of enamel, with casein showing a trend for better protection. For dentin, no reduction in the erosive potential was observed for the tested protein-modified orange juices.

The Future of Fluorides and Other Protective Agents in Erosion Prevention

The effectiveness of fluoride in caries prevention has been convincingly proven. In recent years, researchers have investigated the preventive effects of different fluoride formulations on erosive tooth wear with positive results, but their action on caries and erosion prevention must be based on different requirements, because there is no sheltered area in the erosive process as there is in the subsurface carious lesions. Thus, any protective mechanism from fluoride concerning erosion is limited to the surface or the near surface layer of enamel. However, reports on other protective agents show superior preventive results. The mechanism of action of tin-containing products is related to tin deposition onto the tooth surface, as well as the incorporation of tin into the near-surface layer of enamel. These tin-rich deposits are less susceptible to dissolution and may result in enhanced protection of the underlying tooth. Titanium tetrafluoride forms a protective layer on the tooth surface. It is believed that this layer is made up of hydrated hydrogen titanium phosphate. Products containing phosphates and/or proteins may adsorb either to the pellicle, rendering it more protective against demineralization, or directly to the dental hard tissue, probably competing with H+ at specific sites on the tooth surface. Other substances may further enhance precipitation of calcium phosphates on the enamel surface, protecting it from additional acid impacts. Hence, the future of fluoride alone in erosion prevention looks grim, but the combination of fluoride with protective agents, such as polyvalent metal ions and some polymers, has much brighter prospects.