These include the adhesiveness (stickiness) and clearance time of dietary carbohydrates, as well as the frequency of exposure to them. In general, those dietary carbohydrates that are sticky confer the highest potential for caries. This was first demonstrated in the Vipeholm Study, which had study subjects consume sucrose in toffee, chocolate, caramel, bread, or in a liquid form. It was shown that the intake of sticky foods like toffees and caramels produced higher caries rates among monitored subjects than those who consumed rapidly swallowed sugars.1 The increase in caries activity disappeared when sugar-rich foods were reduced or removed from the diet. However, the cariogenicity of liquid sugars should not be discounted given the high incidence of caries associated with soft-drink consumption and the occurrence of early childhood (“baby bottle”) caries.5
Figure 2. Early Childhood Caries.
It is also important to consider the clearance rate of dietary carbohydrates in the caries process. Different foods are cleared from the oral cavity at different rates. For example, sticky, retentive foods such as toffees, or foods that can compact in the pits-and-fissures of the teeth, such as biscuits and cakes, have increased clearance times. In general, refined carbohydrates that are retained for long periods tend to be the most cariogenic.3,5 Also, bacterial acid production can persist after the carbohydrate has cleared from the oral cavity.
The link between the frequency of carbohydrate intake and caries incidence was also investigated in The Vipeholm Study. When study subjects ingested 300 g of sugar with meals, a significantly lower caries rate was observed (0.43 new carious lesions per year) compared to subjects ingesting the same amount of sugar as snacks between meals (4.02 new carious lesions annually).1
Figure 3. Vipeholm Study.