Twenty-one methylmethacrylate screw implants were inserted in the jaws of three Labrador dogs. Clinical, radiographic, microscopic and fluorescence microscopic examinations were performed. Direct bone-implant contact was found in all firm implants, and the density of the alveolar bone increased towards the screw surface. In these areas no fibrous tissue was found between bone and implant. Horizontal fibres at the junction between the head and the neck of the implant seem to have impeded downgrowth of subepithelial granulation tissue.