Development of low erosive carbonated fruit drinks. 1. Evaluation of two experimental orange drinks in vitro and in situ

Fluoride toothpastes containing micrometric or nano-sized sodium trimetaphosphate reduce enamel erosion in vitro

OBJECTIVE

To evaluate the effect of fluoride toothpastes supplemented with micrometric or nano-sized sodium trimetaphosphate (TMP or TMPnano, respectively) on enamel erosion in vitro, as well as the influence of salivary acquired pellicle and saliva.

MATERIAL AND METHODS

Bovine enamel blocks (n = 120) were randomly assigned into the following experimental toothpastes: no F/TMP/TMPnano (Placebo); 1100 ppm F (1100 ppm F); 1100 ppm F plus 3% TMP or 3% TMPnano (1100 TMP or 1100 TMPnano, respectively) and 5000 ppm F (5000 ppm F). Erosive challenge was performed by immersion of the blocks in citric acid for 5 min, followed by 2 h immersion in human or artificial saliva, 4×/day, during 5 days. After each erosive challenge, blocks were exposed to slurries of the toothpastes. Enamel erosion (µm), surface hardness (SHf) and cross-sectional hardness (ΔKHN) were analyzed as response variables and the data were submitted to two-way ANOVA, followed by the Student-Newman-Keuls test (p < .05).

RESULTS

1100 TMPnano significantly reduced enamel loss when compared to 1100 TMP (p = .002), reaching values similar to those promoted by 5000 ppm F (p = .96). 1100 ppm F presented significantly lower enamel loss than Placebo (p < .001), and higher than 1100 TMP (p < .001). Significantly higher SHf and lower ΔKHN was observed for 1100 TMPnano and 5000 ppm F when compared with the other groups (p < .001). The type of saliva did not influence enamel erosion, SHf and ΔKHN for the groups treated with TMP-containing toothpastes.

CONCLUSION

The addition of 3% TMPnano to 1100 ppm F toothpastes significantly increases the protective effect against enamel erosion in vitro when compared with its counterparts with micrometric TMP or without TMP. This effect was not influenced by the presence of acquired enamel pellicle and saliva.

Possible ways of reducing dental erosive potential of acidic beverages

Frequent consumption of acidic beverages is related to excessive tooth wear, namely dental erosion. Preventive measures may involve reduction or elimination of acidic drink consumption. However, the success of this approach is difficult to achieve as it is highly dependent on patient compliance. Therefore, a practical way of minimizing the erosive potential of popular acidic drinks may be their chemical modification. The aim of this article was to review the different methods of modification and their shortcomings. The available literature demonstrates that the erosive potential of most acidic beverages could be reduced. To date, the effectiveness of soluble calcium salts supplementation is the best established. However, modification can reduce the sensorial quality of the drink and shorten its shelf-life. There is also a need to evaluate the lowest effective and safe dose of the additive.

A randomised in situ trial, measuring the anti-erosive properties of a stannous-containing sodium fluoride dentifrice compared with a sodium fluoride/potassium nitrate dentifrice

OBJECTIVES

To determine if a stabilised, stannous-containing sodium fluoride dentifrice provides greater enamel protection in situ against intraoral dietary erosive challenges compared with a sodium fluoride/potassium nitrate dentifrice.

METHODS

A single-centre, investigator blind, randomised, supervised, two-treatment, non-brushing, four-period crossover in situ study was undertaken, with each test period being 15 days. Thirty-five healthy adult subjects were recruited to participate in the study, which included four erosive acid challenges per day. Subjects were randomised to product treatment, which included either: (1) a stannous-containing sodium fluoride dentifrice (Oral-B(®) Pro-Expert Sensitive) or (2) a sodium fluoride/potassium nitrate dentifrice (Sensodyne(®) Pronamel(®) ). Each study subject wore an intraoral appliance retaining two sterilised, polished human enamel samples for 6 hours/day. Subjects swished with an allocated dentifrice slurry twice a day and with 250 ml of orange juice for 10 minutes (25 ml/minute over a 10-minute period) four times per day. The primary and secondary outcomes for this study were enamel loss measured using contact profilometry at days 15 and 5, respectively, using parametric analysis methods.

RESULTS

At day 15, a 38% lower enamel loss (P < 0.0001) was observed, with estimated medians of 2.03 μm (SE 0.247) and 3.30 μm (SE 0.379), in favour of the stannous-containing dentifrice. At day 5, specimens treated with the stannous-containing sodium fluoride dentifrice demonstrated 25% less enamel loss than those treated with the sodium fluoride/potassium nitrate dentifrice. Treatment differences at day 5 were also statistically significant (P < 0.05), with estimated medians of 1.37 μm (SE 0.177) and 1.83 μm (SE 0.223), respectively.

CONCLUSIONS

Results of this in situ study suggest the stabilised, stannous-containing sodium fluoride dentifrice could be used to provide significantly greater protection to enamel from erosive acid challenge compared with that provided by conventional fluoride-containing products.

Iron supplementation reduces the erosive potential of a cola drink on enamel and dentin in situ

Iron has been suggested to reduce the erosive potential of cola drinks in vitro.

Effect of pepsin on erosive tissue loss and the efficacy of fluoridation measures in dentine in vitro

OBJECTIVES

In dentine, erosive lesion progression and efficacy of fluoridation measures for symptomatic therapy of dental erosion are both dependent on the presence of the organic matrix. In patients with eating disorders in combination with chronic vomiting, the demineralized organic matrix can be degraded by gastric enzymes. The aim of this study was to investigate the effect of pepsin on erosion progression and the efficacy of fluoride in dentine.

MATERIAL AND METHODS

Human dentine specimens were prepared and randomly divided into 4 groups of 20 specimens each. They were subjected to a cyclic de- and remineralization procedure for 9 days. For demineralization (6 x 2 min per day), an HCl solution (pH 1.6) was used in all groups. In two groups, pepsin (1.5 mg mL(-1)) was added to the demineralization solution. Fluoridation was performed in two groups 6 x 1 min per day with a mouth rinse (Olaflur/SnF(2); 250 ppm F(-)) after demineralization with both the HCl solution and the pepsin containing solution. Degradation of collagen was quantified by analyzing hydroxyproline and tissue loss was determined microradiographically. SEM images were taken in addition.

RESULTS

In the pepsin group, 1.72 (0.26) microg mL(-1) (mean (SD)) hydroxyproline per day was detected, and in the pepsin-fluoride group 1.95 (0.50) microg mL(-1). Tissue loss after 9 days in the control group was similar to that in the pepsin group (122.2 (53.4) microm and 122.2 (38.0) microm, n.s., respectively). Fluoridation reduced tissue loss after demineralization (98.8 (30.2) microm) but not after pepsin treatment (125.2 (34.2) microm; p< or =0.05).

CONCLUSION

Under the conditions used, pepsin had no influence on tissue loss, but altered the efficacy of fluoridation measures.

Effect of iron on the dissolution of bovine enamel powder in vitro by carbonated beverages

OBJECTIVES

The aim of this study was to evaluate, in vitro, the effect of iron on the dissolution of bovine enamel powder, when added to two carbonated beverages.

DESIGN

Powdered enamel was produced by griding enamel fragments of bovine incisor in a steel pestle and mortar. Particles between 75 and 106 microm were selected using appropriated meshes. At time zero, the carbonated beverage (Coke or Sprite Zero) was added to powdered enamel (1 mg enamel powder/10 microL of beverage) and vortexed for 30 s. The sample was immediately centrifuged (11,000 rpm) for 30 s and the supernatant was removed at 1 min 40 s. This procedure was repeated five times with the beverage containing increasing ferrous sulphate concentrations (1.25, 2.5, 5, 10, 15, 30 and 60 mmol/L). The phosphate released in the medium was analysed spectrophotometrically. Data were analysed using ANOVA and Tukey's test (p<0.05).

RESULTS

When iron at 30 and 60 mmol/L was added to Coke, a significant reduction in the dissolution of powdered enamel was observed when compared to control (11 and 17%, respectively), while lower iron concentrations did not have any effect on enamel powder dissolution. Regarding Sprite Zero, iron concentrations up to 10 mmol/L had no significant effect, while higher concentrations significantly increased enamel powder dissolution.

CONCLUSIONS

The results suggest that iron can interfere with the dissolution of dental enamel powder in the presence of acidic beverages and the type of acid in these beverages seems to modulate this effect.

Effect of iron on acid demineralisation of bovine enamel blocks by a soft drink

OBJECTIVES

The aim of this study was to evaluate, in vitro, the effect of iron on the acid demineralisation of bovine enamel blocks by a soft drink.

DESIGN

Twenty-four blocks of bovine enamel were randomly assigned to two groups (experimental and control), which were exposed to 4 cycles of demineralisation in Coke containing or not 10 mmol/L of iron, respectively, and another 4 cycles of remineralisation in artificial saliva. The softening of enamel was evaluated by % superficial microhardness change (SMHC) and wear analysis. Data were analysed using t-test (p<0.05).

RESULTS

With regard to %SMHC, the experimental group presented average values (+/-S.E.) of -85.3+/-0.9, that were significantly higher (t=4.7, p<0.01) than the ones observed for control group (-76.7+/-1.6). The experimental group presented a mean wear (+/-S.E.) of 2.3+/-0.2 microm, that was significantly lesser (t=3.7, p<0.01) than the one observed for the control group (3.5+/-0.2 microm).

CONCLUSIONS

According to this protocol, iron at 10 mmol/L significantly reduced the wear, but significantly enhanced the %SMHC of enamel blocks submitted to erosion by Coke.

An in vitro investigation of the effect of some analgesics on human enamel

The sale of over-the-counter pain relief medication has increased dramatically in recent years, and typically amounts to several hundred thousands of pounds per year in the UK. Many soluble analgesic preparations contain citric acid, and it has been suggested that these formulations may cause dental erosion. The aim of this study was to investigate the effect of some over-the-counter analgesics on tooth surface loss from human enamel. Six commonly available analgesics were chosen for this study and the effect of immersing unerupted human enamel was examined using non-contact optical profilometry. Two of the six analgesics investigated caused no detectable erosion (Boots soluble aspirin and Anadin Extra). Three caused statistically significant enamel erosion, but this was very slight and is thought to be clinically insignificant (Alka Seltzer, Panadol and Solpadeine). Only one analgesic caused possible potentially clinical significant enamel erosion. Further studies are needed to determine whether Aspro causes clinically significant enamel erosion.

Effect of Salivary Stimulation on Erosion of Human and Bovine Enamel Subjected or Not to Subsequent Abrasion: An in situ/ex vivo Study

This in situ/ex vivo study evaluated whether saliva stimulated by chewing gum could prevent or reduce the wear and the percent change in microhardness (%SMH) of bovine and human enamel submitted to erosion followed by brushing abrasion immediately or after 1 h. During 2 experimental 7-day crossover phases, 9 previously selected volunteers wore intraoral palatal devices, with 12 enamel specimens (6 human and 6 bovine). In the first phase, the volunteers immersed the device for 5 min in 150 ml of cola drink, 4 times per day (at 8, 12, 16 and 20 h). Immediately after the immersions, no treatment was performed in 4 specimens, 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice, and the device was replaced into the mouth. After 60 min, the remaining 4 specimens were brushed. In the second phase, the procedures were repeated, but after the immersions, the volunteers stimulated the salivary flow rate by chewing a sugar-free gum for 30 min. Changes in wear and %SMH were measured. ANOVA and Tukey's test showed statistical differences (p<0.05) for the following comparisons. The chewing gum promoted less wear and %SMH. A decreasing %SMH and an increasing enamel wear were observed in the following conditions: erosion only, 60 min and 0 min. The human enamel presented greater %SMH and less wear compared to bovine enamel. The data suggest that the salivary stimulation after an erosive or erosive/abrasive attack can reduce the dental wear and the %SMH.

A methodology for testing the erosive potential of sports drinks

OBJECTIVES

The aim of the study was to develop and test a methodology in situ, which simulated the consumption of sports drinks. A secondary aim was to assess the acceptability of the method to sedentary participants.

METHODS

To select the sports drink for the study in situ, five commercially available sports drinks were examined for erosive potential in vitro. The study in situ was a single centre, 2-period, 2-treatment crossover study to compare the erosive effect of a commercially available sports drink (Test), with that of mineral water (Control), over 10 day periods on 10 healthy volunteers. Subjects wore upper removable appliances containing two human enamel specimens from 9 a.m. to 5 p.m. The regimen of intake of the drinks was 350 ml in 10, 5-min rest, 650 ml in 25, 5-min rest, 500 ml in 10 and 5-min rest. Measurements of enamel loss were made on samples after 5 and 10 days by profilometry.

RESULTS

The in situ study showed a statistically significant difference in erosive potential between the test and control beverages. No specimen exposed to the control beverage displayed appreciable erosion. Erosion occurred with the test drink, but to a variable degree between subjects. The subjects unanimously found the drinking regimen unpleasant.

CONCLUSIONS

The sports drink caused significantly more erosion in situ than water and as seen in other studies, there was marked variation in susceptibility to erosion between subjects. The new drinking regimen was designed to simulate pre, during and post-exercise intake. Although all the sedentary subjects participating in this study reported that they found the volume of fluids consumed over a short period of time excessive it is unlikely that this would prove problematic in the exercise environment.

Development of low erosive carbonated fruit drinks 2. Evaluation of an experimental carbonated blackcurrant drink compared to a conventional carbonated drink

OBJECTIVE

Previous studies demonstrated that a non-carbonated blackcurrant juice drink with added calcium produced little erosion of enamel in vitro and in situ by comparison with other low pH fruit drinks. The aim of this study is to evaluate the erosive effects in situ of an experimental formulation carbonated drink with added calcium, compared to a conventional carbonated drink over a 20 day period using a similar design as in previous studies.

METHOD

The study was a single centre, single blind, randomised placebo controlled three cell crossover design involving 15 volunteers. The test drinks were an experimental carbonated ready-to-drink (RTD) blackcurrant drink, a conventional carbonated RTD orange drink and water. Two enamel samples were retained in situ, in the midline of the hard palate on an upper removable acrylic appliance. Drinks were 250 ml volumes consumed four times per day during 20 working days. Measurements of enamel loss were made on enamel samples after days 2, 5, 10, 15 and 20 by profilometry.

RESULTS

The experimental carbonated blackcurrant drink caused significantly less enamel loss than the conventional carbonated orange drink at all time points measured, but was not significantly different from water at days 2, 5 and 20.

CONCLUSIONS

This study has shown that it is possible to modify carbonated soft drinks in a manner similarly shown with non-carbonated soft drinks, to minimise dental erosion.