Abstract: Bone resorption from and invagination of epithelial tissue around periodontally involved teeth can be arrested and reversed by coating the affected areas of the tooth roots with a nontoxic, biocompatible composition which acts as a shield against bacterial toxins and which is capable of supporting biological attachment of cells in the gingiva. This treatment allows the periodontally involved region to heal by providing improved physiological and mechanical support of the tooth by its bone socket. In a preferred embodiment of the invention, the treatment involves coating the root surfaces of periodontally involved teeth with a film consisting of a polycarbonate resin in methylene chloride solvent.This invention also provides a process for stopping and reversing resorption of bone from, and invagination of epithelial tissue around, screws, pins, blades, and other metal inserts which have been placed in bones, particularly dental implants placed in alveolar bone.