G.A. Luke H. Gough J.A. Beeley D.A.M. Geddes
Oral Sciences, University of Glasgow Dental Hospital and School, Glasgow, Scotland, UK

Abstract

The aetiology of dental caries is in part related to the re- tention time of dietary carbohydrates in the oral cavity and their subsequent metabolism by the oral bacteria. Salivary clearance of fermentable carbohydrates from three different foodstuffs was examined in 5 subjects and analyses performed by high-performance anion-ex- change chromatography with pulsed amperometric de- tection. The clearance of glucose, fructose, sucrose, mal- tose and sorbitol rinses was studied as well as that of chocolate bars, white bread and bananas. Of the sugar rinses studied, sucrose was removed from saliva most rapidly whilst appreciable levels of sorbitol remained even after 1 h. Clearance of residual carbohydrates from bananas and chocolate bars seemed marginally faster than in the case of bread, but sucrose levels still tended to fall more quickly than other carbohydrates studied. Surprisingly, carbohydrate residues from the three foods studied were still present in the mouth even 1 h after in- gestion, which is longer than has hitherto been reported.

Dental caries is initiated by the consumption of fer- mentable carbohydrates which are converted into organic acids by bacteria in dental plaque. The rise in acidity can cause demineralisation. Since cariogenic effects are, in part, related to the retention time of carbohydrates in the mouth as a result of their acidogenicity, the role of saliva in oral carbohydrate clearance is of primary interest. The salivary clearance of sugars is influenced by the properties of the foodstuff [Lundqvist, 1952], the amount of ingested carbo- hydrate [Goulet and Brudevold, 1984], the sampling site in the mouth [Britse and Lagerlöf, 1987; Strong et al., 1987] and physiological factors such as salivary flow rate and the volume of saliva in the mouth before and after swallowing [Dawes, 1983; Lagerlöf et al., 1987].

Analytical methods for the determination of carbohy- drates in foods and biological fluids include enzymatic methods [Hase et al., 1987; Lindfors and Lagerlöf, 1988; Weatherell et al., 1989] and chromatographic techniques in- cluding paper chromatography and thin layer chromatogra- phy [Carlson, 1968; Anumula and Spiro, 1983]. High per- formance ion-exchange chromatography combined with pulsed amperometric detection (HPIEC-PAD) provides the most selective and sensitive method currently available for analysing complex samples containing carbohydrate-con- taining samples such as saliva [Gough et al., 1996]. The procedure can be used on small sample volumes (50 μl) and can simultaneously determine the level of more than one carbohydrate in any given sample. Using this technique we have examined the clearance from saliva of the carbohy- drates glucose, fructose, sucrose, maltose and sorbitol after a mouth rinse and the clearance of relevant sugars after eat- ing carbohydrate containing-foods.

J.A. Beeley
Oral Sciences, University of Glasgow Dental Hospital and School 378 Sauchiehall Street
Glasgow G2 3JZ, Scotland (UK)
Tel. +44 0141 211 9755, Fax +44 0141 353 1593