Biomedical subjects

T H Grenby

Publications and source records attributed to T H Grenby.

At least 19 recordsLinked to original sources

PubMed2001

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.

Animals↗

PubMed2000

Properties of maltodextrins and glucose syrups in experiments in vitro and 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 techniques in vitro and 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 alpha-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 alpha-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.

Analysis of Variance↗

PubMed1996

Methods of assessing erosion and erosive potential.

Methods for use in vitro are reviewed first, classified under the examination of extracted teeth, chemical and physical methods, digital image analysis, scanning electron microscopy and other potentially useful techniques. Methods for recording erosion in laboratory animals are dealt with next, including techniques that can also be used in vitro, Restarski's system and various modifications of it, and digital image analysis. Thirdly the main systems and indices that have been designed for clinical use are arranged under case histories and clinical examination, scales of severity and indices of diagnosis of varying complexity. Finally, some of the main advantages and limitations of the techniques are summarized.

Acids↗

PubMed1996

Lessening dental erosive potential by product modification.

Current interest in dental erosion has led to increasing attention to ways in which potentially erosive products might be modified. Information on how this could be achieved has been hard to gather, and has focused chiefly on possibilities in reformulating soft drinks. The bulk of the work published on this relates to calcium and phosphate supplementation, ranging from early experimentation on saturation of a demineralising medium with tricalcium phosphate, through tests of more soluble phosphates and other calcium salts providing various levels of Ca2+ and PO4(3-), to a calcium citrate malate additive specially formulated to curb erosion by soft drinks. Opinions on the effectiveness of citrate, the practicability of reducing the acidity levels of soft drinks, and the possible applications of fluoride, bicarbonates and certain constituents of milk products are also included. Finally, an attempt has been made to summarize some of the advantages and shortcomings of the different methods, but it is clear that much further work will be needed before firm guidelines on the best routes to product improvement can be laid down.

Acids↗

PubMed1996

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.

Analysis of Variance↗

PubMed1995

The use of sanguinarine in mouthwashes and toothpaste compared with some other antimicrobial agents.

Dental practitioners say that they get information to answer patients' queries on mouthwashes chiefly from their studies in periodontology and from articles in the British Dental Journal. Most practitioners who were asked about this knew of the benefits of Corsodyl (chlorhexidine) and fluoride-containing rinses, but few were aware of the active ingredients and effectiveness of the wide range of mouthwashes now on the market. The majority said they would welcome more information on this. This review was undertaken because there was a move to introduce mouthwashes containing sanguinarine into the UK. Part of its appeal would be that it is a natural therapeutic product, as distinct from a 'synthetic' or 'artificial' chemical. Information collected from scientific publications on sanguinarine, which has been in use in the USA and on the Continent in mouthwashes and toothpastes, is presented here. The consensus is that (a) it has some assets in curbing supragingival plaque, although it is uncertain whether the presence of zinc salts assists this, and (b) it is more effective in a mouthwash than in a toothpaste. It appears to be less effective than chlorhexidine, but no direct comparisons with triclosan preparations have been discovered. Like other mouthwashes, it does not affect subgingival plaque.

Alkaloids↗

PubMed1995

Dental properties of antiseptic throat lozenges formulated with sugars or Lycasin.

Thirteen different formulations of throat lozenges were examined for their acidity, demineralizing action on hydroxylapatite, and fermentability by human dental plaque micro-organisms. Their flavouring acids gave them low pH values in the range 2.6-3.7, leading to the dissolution of calcium and phosphorus from hydroxylapatite. The combination of antiseptics and flavouring acids in the lozenges inhibited microbial growth and metabolism. In the absence of any antiseptics and flavouring acids, the growth and metabolic activity of cultures of plaque micro-organisms were significantly greater on sucrose+glucose lozenges than on a new Lycasin formulation.

Administration, Oral↗

PubMed1995

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.

A new electronic system was set up for accurately regulating the amount and frequency of food dispensed to laboratory rats so that investigations of the cariogenic potential of foods can be carried out under strictly controlled conditions according to the stipulations of the San Antonio Consensus Conference, 1985. The system was used to evaluate the cariogenicity of sucrose incorporated into plain and milk chocolate. The results suggested that 18.75% of sucrose in the diet had the same cariogenic potential no matter whether it was in the form of fine crystals or incorporated into plain chocolate, but mean caries scores were nearly 30% higher on a plain chocolate than on a milk chocolate regime.

Animals↗

PubMed1995

The use of high-phosphorus supplements to inhibit dental enamel demineralisation by ice lollies.

Five new formulations of water ice lollies with a high-phosphorus (low Ca) supplementation ratio were tested for their erosiveness of dental enamel or hydroxylapatite in vitro. Compared with the basic unsupplemented lolly, all five formulations that had been prepared with additional calcium and phosphorus, but in a low Ca/P ratio, as potential inhibitors of demineralisation, were associated with significantly less attack on dental mineral, as measured by the dissolution of calcium and phosphorus.

Calcium↗

PubMed1993

Erosion by soft drinks of rat molar teeth assessed by digital image analysis.

A digital imaging analysis (DIA) procedure for recording and assessing erosive changes on teeth was developed and evaluated against an older subjective method. Results after exposure of rats' teeth to various soft drinks showed that the DIA system was superior to the conventional method, with improved precision. The system provided a direct and highly sensitive means of quantifying the erosion of dental hard tissues by three different soft drinks, showing that it could be used to evaluate erosiveness and other dental damage. After 6 weeks' exposure to soft drinks in the diet, the area of intact enamel on the lingual surface of the first mandibular molar averaged 47% on apple juice, 27% on still orange and 6% on carbonated orange. The greatest exposure of dentine (36%) was on the still orange drink. Eroded enamel accounted for 72.5% of the tooth surface on the carbonated drink.

Animals↗

PubMed1991

Advances in non-caloric sweeteners with dental health advantages over sugars.

Many factors have to be considered in developing new intense sweeteners to replace sugars in the diet for the benefit of dental health. These include their general properties, safety and toxicological evaluation, metabolic fate in the body, regulatory status and dental research documentation. The choice of new sweeteners with improved properties is expanding, with particular attention being paid to multiple sweetening, materials of natural origin and calorie control, as well as dental health gains, the distinction between non-cariogenic and anti-cariogenic properties, securing regulatory approval and developing an attractive range of foods and drinks containing the new materials.

Carbohydrates↗

PubMed1991

Update on low-calorie sweeteners to benefit dental health.

Ten different types of high-intensity, low-calorie sweeteners that have potential dental applications as sugar substitutes are appraised, taking into consideration their general properties, safety and toxicological assessment, metabolic fate in the body, regulatory status and any dental research that has been carried out on them. Attention focuses on the continuing expansion in the wide diversity of types of sweeteners becoming available, the multiple sweetener concept, the growing interest in materials of natural origin, and the distinction between non-cariogenic and actively anti-cariogenic properties of the individual sweeteners.

Humans↗

PubMed1990

Snack foods and dental caries. Investigations using laboratory animals.

The nation's eating habits are undergoing major transformation, with a swing away from traditional meals to a huge increase in snack consumption, but very little is known of the nutritional and dental implications of this change. The research project reported here evaluated a range of snack foods in caries-active laboratory animals, comparing them, as dietary ingredients, with noncariogenic and cariogenic (sugar) diets. The findings showed the very low cariogenicity of salted peanuts, followed by ready-salted and salt and vinegar crisps, extruded maize, mixed-starch and prefabricated/fried potato products, and cheese-filled puffs. Other varieties of crisps (cheese and onion and special shapes) proved to be more cariogenic, not far short of semi-sweet biscuits in some cases. It is concluded that the severity of the processing undergone by the snack foods and the nature of the flavouring agents with which they are coated can influence their dental properties.

Analysis of Variance↗

PubMed1990

Potential dental effects of infants' fruit drinks studied in vitro.

Eighteen different infants' drinks from five manufacturers were examined for their carbohydrate, calcium, phosphorus and acid contents, and their attack on tooth mineral. Seven of the drinks were compared with nine varieties of adults' soft drinks, and demineralization was studied with and without the presence of a cariogenic oral streptococcus. The influence of the acids already in the drinks in dissolving Ca and P outstripped that of any acid generated in these studies in vitro by microbial fermentation of the sugars they contained, giving an indication of their relative erosiveness rather than their cariogenic action. Various other features of the drinks relevant to dental health were identified. Titratable acid was a better guide than pH to their dental properties. Although there were considerable differences between the various infants' drinks, taken as a group, their acidity levels and demineralizing powers were generally lower than those of the adults' drinks.

Adult↗

PubMed1990

[In vitro experiments on effect of soft drinks on dental enamel].

The composition and dental properties of eight different soft drinks, representing some of the most popular types used in the U.K., were examined. Demineralisation experiments were conducted on hydroxylapatite, the basic component of dental enamel, determining calcium dissolving by atomic absorption spectroscopy and phosphorus by UV/vis spectrophotometry. The titratable acid content of the drinks was found to give a better guide than their pH to their potential dental erosiveness. The sugars content, in their ready-to-drink form, varied from zero in a low-calorie product up to almost 14% in a black-currant drink, but using a technique with a relatively long contact time, and in the absence of intact dental plaque, the demineralising action on hydroxylapatite of the acids already in the drinks eclipsed the effects of the acid generated by oral micro-organisms from the sugars in the drinks. The pure citrus juices showed potentially the worst dental properties, followed by the orange and blackcurrant concentrates after dilution to their ready-to-drink form, with least demineralisation from the carbonated drinks, and a cola drink giving especially low figures.

Carbonated Beverages↗

PubMed1989

The possible dental effects of children's rusks: laboratory evaluation by two different methods.

In response to concern over the sugar content and possible dental effects of infants' rusks, a programme of research was undertaken to compare six different kinds of rusk with respect to (a) their cariogenicity in caries-active laboratory rats; (b) their capacity to serve as substrates for acid production by oral microorganisms, and the attack of this acid on dental mineral; (c) the adhesiveness of the rusks to the enamel surface. The caries scores in the animal experiments ranged from very high, with rampant dental destruction, for 31%-sucrose rusks, down to virtually non-cariogenic on a zero-sucrose variety. With only one anomaly, cariogenicity correlated well with sucrose content. The results of the studies in vitro showed good general agreement with the animal data. The sucrose in the rusks, rather than their content of other sugars such as glucose, maltose and lactose, etc, emerged as a major factor in determining their effect on teeth, but cereal components can also play a part in governing adhesiveness and fermentability.

Animals↗

PubMed1989

Laboratory studies of the dental properties of soft drinks.

The composition and dental properties of eight different soft drinks, representing some of the most popular types used in the UK, were examined. Demineralization experiments were conducted on hydroxylapatite, the basic component of dental enamel, determining calcium dissolving by atomic absorption spectroscopy and phosphorus by u.v. visual spectrophotometry. The titratable acid content of the drinks was found to give a better guide than their pH to their potential dental erosiveness. The sugar content, in their ready-to-drink form, varied from zero in a low-calorie product up to almost 14% in a blackcurrant drink, but using a technique with a relatively long contact time, and in the absence of intact dental plaque, the demineralizing action on hydroxylapatite of the acids already in the drinks eclipsed the effects of the acid generated by oral micro-organisms from the sugars in the drinks. The pure citrus juices showed potentially the worst dental properties, followed by the orange and blackcurrant concentrates after dilution to their ready-to-drink form, with least demineralization from the carbonated drinks, and a cola drink giving especially low values.

Beverages↗

PubMed1989

Dental and metabolic effects of lactitol in the diet of laboratory rats.

1. Because so little is known about the properties of lactitol as a possible alternative bulk sweetener to sucrose, it was tested in two large-scale experiments in laboratory rats. Matched groups of caries-active Osborne-Mendel rats were fed on uniform diets containing lactitol and compared with a sucrose control in both experiments, plus a xylitol control in the first experiment. 2. In the early stages of the experiments weight gains and food utilization were better on the sucrose than on the lactitol regimens. Body-fat storage was higher on the sucrose than on the polyol regimens. 3. At the end of 8 weeks the mandibular molars were examined for dental plaque accumulation and dental caries. The dental caries scores when 160 g sucrose/kg in the diet was replaced by lactitol were lower by a highly significant margin, bringing them down to the same low level as those on a 160 g xylitol/kg regimen. 4. Testing lactitol in a manufactured food product, shortbread biscuits, in comparison with ordinary sucrose biscuits, showed differences in plaque scores (significant) and caries levels (highly significant), with 60% fewer lesions on the lactitol regimen. 5. The results confirm the low cariogenic potential of lactitol, but show metabolic differences compared with sucrose.

Animals↗