Precise control of the frequency and amount of food provided for small laboratory animals by a new electronic metering technique, used to evaluate the cariogenic potential of chocolate

Cariogenic potential of milk and infant formulas: a systematic review

AIM

To assess the cariogenic potential of cow's milk, human milk and infant formulas in comparison to sucrose in animal models.

METHODS

Electronic search of the following databases were undertaken: PubMed-MEDLINE, MeSH and ingentaconnect. In addition, the reference lists of all eligible studies were searched. Characteristics such as animal species were used; comparisons and outcomes measured were analysed.

RESULTS

The search yielded a total of 13 articles of which six studies met the inclusion criteria and seven were excluded. All the six included studies used rat models for assessing the cariogenic potential of the test groups. Cow's milk was compared with sucrose in all of the six studies, reporting cow's milk to be less cariogenic than sucrose. Two studies compared human milk to sucrose and reported human milk to be less cariogenic than sucrose, but more than that of cow's milk. Although infant formulas were compared with sucrose in four studies, their cariogenic potential was a matter of some ambiguity.

CONCLUSION

The evidence suggests that cow's milk and human milk are less cariogenic than sucrose, with cow's milk being the least cariogenic. The cariogenic potential of infant formulas varied across the studies, with some being as cariogenic as sucrose.

Properties of maltodextrins and glucose syrups in experimentsin vitroand in the diets of laboratory animals, relating to dental health

The objective of the study was to examine the cariogenic potentials of maltodextrins and glucose syrups (two glucose polymers derived from starch) using a range of techniquesin vitroand in laboratory animals. The experimental methods used were: (1) measurement of acid production from glucose syrups and maltodextrins by human dental plaque micro-organisms; (2) evaluation of the role salivary α-amylase in degrading oligosaccharides (degree of polymerisation >3) in the glucose polymers, estimating the products by HPLC; (3) assessment of the fermentability of trioses relative to maltose; (4) measurement of dental caries levels in three large-scale studies in laboratory rats fed on diets containing the glucose polymers. It was found that acid production from the glucose polymers increased as their higher saccharide content fell. Salivary α-amylase rapidly degraded the oligosaccharides (degree of polymerisation >3), mainly to maltose and maltotriose. In the presence of oral micro-organisms, maltotriose took longer to ferment than maltose, but by the end of a 2 h period the total amount of acid produced was the same from both. Incorporated into the diets in solid form, the glucose syrups and maltodextrins were associated with unexpectedly high levels of dental caries. In conclusion, the findings were unforeseen in the light of earlier data that a glucose syrup was less cariogenic than sucrose.

The effect of cocoa polyphenols on the growth, metabolism, and biofilm formation by Streptococcus mutans and Streptococcus sanguinis

The aim of this study was to determine if cocoa polyphenols could interfere with biofilm formation by Streptococcus mutans or Streptococcus sanguinis, and reduce acid production from sucrose by S. mutans. The antimicrobial activity of cocoa polyphenols was assessed against cariogenic (S. mutans) and health-associated (S. sanguinis) species by minimum inhibitory concentration assays. Cocoa polyphenol dimer, tetramer, and pentamer inhibited the growth of S. sanguinis, whereas the growth of S. mutans was unaffected. However, pretreatment of surfaces with cocoa polyphenol pentamer (35 microM) reduced biofilm formation by S. mutans at 4 and 24 h, whereas the effects on S. sanguinis were less consistent. In contrast, brief exposure of preformed biofilms to pentamer either had no significant effect or resulted in increased counts of S. mutans under certain conditions. Cocoa polyphenol pentamer (500 microM) significantly reduced the terminal pH, and inhibited the rate of acid production by S. mutans at pH 7.0. In conclusion, cocoa polyphenols can reduce biofilm formation by S. mutans and S. sanguinis, and inhibit acid production by S. mutans.

Food starches and dental caries

Sucrose and starches are the predominant dietary carbohydrates in modern societies. While the causal relationship between sucrose and dental caries development is indisputable, the relationship between food starch and dental caries continues to be debated and is the topic of this review. The current view of dental caries etiology suggests that in-depth evaluation of the starch-caries relationship requires the consideration of several critical cariogenic determinants: (1) the intensity (i.e., the amount and frequency) of exposure of tooth surfaces to both sugars and starches, (2) the bioavailability of the starches, (3) the nature of the microbial flora of dental plaque, (4) the pH-lowering capacity of dental plaque, and (5) the flow rate of saliva. Studies of caries in animals, human plaque pH response, and enamel/dentin demineralization leave no doubt that processed food starches in modern human diets possess a significant cariogenic potential. However, the available studies with humans do not provide unequivocal data on their actual cariogenicity. In this regard, we found it helpful to distinguish between two types of situations. The first, exemplified by our forebears, people in developing countries, and special subject groups in more modern countries, is characterized by starch consumption in combination with a low sugar intake, an eating frequency which is essentially limited to two or three meals per day, and a low-to-negligible caries activity. The second, exemplified by people in the more modern societies, e.g., urban populations, is characterized by starch consumption in combination with significantly increased sugar consumption, an eating frequency of three or more times per day, and a significantly elevated caries activity. It is in the first situation that food starches do not appear to be particularly caries-inducive. However, their contribution to caries development in the second situation is uncertain and requires further clarification. Although food starches do not appear to be particularly caries inducive in the first situation, the possibility cannot be excluded that they contribute significantly to caries activity in modern human populations. The commonly used term "dietary starch content" is misleading, since it represents a large array of single manufactured and processed foods of widely varying composition and potential cariogenicity. Hence, increased focus on the cariogenicity of single starchy foods is warranted. Other aspects of starchy foods consumption, deserving greater attention, include the bioavailability of starches in processed foods, their retentive properties, also in relation to sugars present (starches as co-cariogens), their consumption frequency, the effect of hyposalivation on their cariogenicity, and their impact on root caries. The starch-caries issue is a very complex problem, and much remains uncertain. More focused studies are needed. At present, it appears premature to consider or promote food starches in modern diets as safe for teeth.

Dental caries-protective agents in milk and milk products: investigations in vitro

OBJECTIVES

To characterise and identify the anti-dental caries components that exist in milk and milk products.

METHODS

Standard enamel or hydroxyapatite demineralisation tests were devised to simulate the action of acid on tooth mineral, and they were used to show which constituents of milk possessed a potential protective action against acid attack.

RESULTS

Milk and milk products were fractionated and tested, revealing that minerals, including calcium and phosphorus, played a part in this protective process. The findings also drew attention to the effectiveness of minor milk protein or protein-associated components, the structures of which are mostly known, which were separated and characterised by gel electrophoresis as proteose-peptone fractions 3 and 5. The strength of adsorption of the protein or polypeptides in these fractions to dental enamel was measured and found to be sufficient to reduce the extent of demineralisation of enamel by acid buffer solutions.

CONCLUSIONS

The removal of lactose, fat, casein and other proteins had little influence on the protective effect of the milk fractions. Besides calcium and phosphorus, milk contains other more powerful protective factors, which were identified as proteose-peptone fractions 3 and 5. Details of their composition and the strength of their adherence to the surface of dental mineral are given.

Cariostatic activity of cacao mass extract

Chocolate is suspected to contain some caries-inhibitory substances. The cariostatic activity of cacao mass extract (CM), the main component of chocolate, was examined in vitro and in experimental animals. CM showed no detectable effects on the cellular growth and acid production of mutans streptococci. On the other hand, the cell-surface hydrophobicity of mutans streptococci was significantly reduced by the presence of CM. Furthermore, insoluble glucan synthesis by the glucosyltransferases from either Streptococcus mutans MT8148R or Strep. sobrinus 6715 was inhibited by CM, but not significantly. Hence, the sucrose-dependent cell adherence of mutans streptococci was also depressed by CM. Finally, CM in both a 40% sucrose diet and drinking water resulted in reductions of caries development and plaque accumulation in rats infected with Strep. sobrinus 6715, but not significantly. These results indicate that cacao mass extract possesses some anticariogenic potential, but its anticaries activity is not strong enough to suppress significantly the cariogenic activity of sucrose.

The effect of milk and sucrose consumption on caries in 6-to-11-year-old Italian schoolchildren

The effect of milk on dental caries was studied on a sample of 6-to-11-year-old Italian schoolchildren. The daily amount of milk consumed and the frequency of consumption of sucrose-containing foods were obtained by a 24-hour dietary diary. In the subsequent oral examination, the level of visible plaque and the number of decayed, extracted and filled teeth (both primary and permanent) of the children were recorded. 439 children (217 boys) who did not use fluoride prophylaxis and with poor oral hygiene were selected from among 890 children. They were divided into three groups according to the frequency of sucrose consumption. The data were statistically analysed using multiple logistic regression. The children consumed a daily average of 209 +/- 133 ml of milk and there were no differences among the three groups in this respect. As expected, the dental health of the children with low sucrose frequency was significantly better than that of the children with high sucrose frequency. The regression on the whole sample showed a weak, significant, negative association between milk consumption and caries (p < 0.05). In the group of high sucrose-consuming children a negative, highly significant association was found (p < 0.001), while in the two groups of low and moderate sucrose-consuming children no association was found. These data suggest that, in the present sample of children who did not use fluoride and with poor oral hygiene, milk has a caries preventive effect only on those subjects with a high daily sucrose-consuming frequency.

Laboratory studies of sweets re-formulated to improve their dental properties

OBJECTIVES

To evaluate the potential dental effects of ten new types of sugar-free sweets formulated with Lycasin or isomalt as bulk sweeteners instead of sugars.

METHODS

Examination of the sweets for their acidity, fermentability by oral microorganisms, influence on the demineralisation of dental enamel, and their influence on human interdental plaque pH, compared with conventional sugar-containing sweets.

FINDINGS

The importance of reducing the levels of flavouring acids in the sweets was demonstrated. It was not straightforward to evaluate chocolate products in this system, but the potential benefits of re-formulating fruit gums, lollipops, chew-bars, toffee and fudge with Lycasin or isomalt in place of sugars were shown by determining their reduced acidogenicity and fermentability compared with conventional confectionery.

CONCLUSIONS

The extent of demineralisation of dental enamel was related to both the acidity and the fermentability of the sweets. Re-formulating sweets with reduced acidity levels and bulk sweeteners not fermentable by dental plaque microorganisms can provide a basis for improving their potential dental effects.