A composition is provided, wherein the composition comprises a water-swellable, water-insoluble polymer, a blend of a hydrophilic polymer with a complementary oligomer capable of hydrogen or electrostatic bonding to the hydrophilic polymer. The composition also includes a backing member. Active ingredients, such as a whitening agent, may be included. The composition finds utility as an oral dressing, for example, a tooth whitening composition that is applied to the teeth in need of whitening. The composition can be designed to be removed when the degree of whitening has been achieved or left in place and allowed to erode entirely. In certain embodiments, the composition is translucent. Methods for preparing and using the compositions are also disclosed.