Effects of chemically modified starches in suspensions and lozenges on pH of human dental plaque

The aim was to evaluate chemically modified starches (CMS) from a cariologic point of view as alternatives to gum arabic in sugar-free lozenges. Two commercial CMS, Purity Gum 40 and Capsul, were selected due to their comparatively low availability to alpha-amylase in vitro. Both gelatinized CMS suspensions and lozenges were tested in vivo by measuring plaque pH. The results showed that suspensions of Purity Gum 40 or Capsul were less available to alpha-amylase in vitro than the soluble starch reference. However, the initial phase of amylolysis was comparatively rapid also with CMS. In spite of the slower rate of hydrolysis, suspensions of the two CMS reduced pH of dental plaque in vivo to the same extent as soluble starch, but somewhat less compared with glucose. Lozenges with Purity Gum 40 also lowered plaque pH, although less than when administered as a precooked suspension. The most prominent pH drop was found with a lozenge containing Purity Gum 40-sucrose-glucose, while tablets with gum arabic-maltitol and pectin-gelatine-Lycasin somewhat increased the pH values. To conclude, it is not recommended to exchange gum arabic for CMS in sugar-free lozenges, since the cariogenic properties of the products are negatively affected.