Intraoral Demineralization and Maltose Clearance from Wheat Starch

Abstract

The ability of cooked starch (CS) and raw starch (RS)to cause intraoral enamel demineralization was determined by the iodide permeability (Ip) test which registers demineralization of enamel by an increase in Ip (+ΔIp) and mineralization by a decrease in Ip (––ΔIp). 5 subjects, who wore a palatal prosthesis holding 8 bovine enamel blocks covered by a layer of Streptococcus mutans swished 15 g of a 10% jelly of CS or 15 ml of a suspension of RS in the mouth for 1 min, and the change in Ip was determined after a period of 45 min. The salivary clearance of maltose during the experiment was also determined. CS gave + ΔIps which were statistically significant in 2 of the 5 subjects. The mean ± SE was +3.6 ± 1.47·10^––10 M of I, indicating mild demineralization. RS gave ΔIps in 4 of the 5 subjects (mean ––6.7 ± 1.87). The rate of salivary clearance of maltose varied considerably among the subjects but CS consistently showed higher initial concentrations than RS. Maximal salivary maltose concentrations ranged from 1,920 to 3,052 mg% for CS and from 523 to 1,041 mg% for RS. The range of the clearance time was from 19.3 to 44.9 min for CS and from 14.7 to 48.2 min for RS. Plotting maltose concentrations against time gave curves which followed an exponential equation. The areas under the curves were calculated, and correlation with the respective Δlps gave r = 0.78. It was concluded that RS had no demineralization potential, and that the demineralizing ability of CS was related to rapid hydrolysis and high early concentrations of maltose in saliva, and unrelated to clearance time.

Food Starches and Dental Caries

“…Studies with this model have shown that raw and cooked wheat starch induced negligible and mild demineralization, respectively (Brudevold et al, 1985), whereas boiled gelatinized wheat starch gels (10, 15, or 20% starch) induced significant demineralization and significant pH drops (minimum pH of 4.8-5.0) (Brudevold et al, 1988). In the study by Kashket et a).…”

“…An intra-oral method has been developed that follows de-or remineralization of blocks of human enamel or dentin, or of bovine enamel, that are covered by a layer of S. mutans cells so as to mimic dental plaque (Brudevold et al, 1985;Kashket et al, 1994). Studies with this model have shown that raw and cooked wheat starch induced negligible and mild demineralization, respectively (Brudevold et al, 1985), whereas boiled gelatinized wheat starch gels (10, 15, or 20% starch) induced significant demineralization and significant pH drops (minimum pH of 4.8-5.0) (Brudevold et al, 1988).…”

Diet, nutrition and the prevention of dental diseases

“…This means plaque pH studies take no account of the protective factors found in some starch-containing food, nor do such studies account for the effect of foods on stimulation of salivary flow. Enamel slab experiments in humans have shown that raw starch does not cause demineralisation 126 and that cooked starch is about one-third to one-half as cariogenic as sucrose 127 . Animal studies have shown that raw starch is of low cariogenicity 128,129 ; cooked starch causes caries but only about half the amount caused by sucrose 130 .…”

Salivary α-Amylase: Role in Dental Plaque and Caries Formation

“…The ability of cooked starch and raw starch to cause enamel demineralization was also investigated using an intraoral demineralization test (Brudevold et al, 1985). This model involves the use of a palatal prosthesis holding bovine enamel slabs coated with a layer of S. mutans.…”