The purpose of this study was to evaluate the usefulness of resorboble collagen membrane for guided tissue regeneration. Dehiscences were surgically induced in dog mandibles Hydroxyapatite-coated or grit-blast-ed implants were then placed in a random pattern in both sides of the mandibles (two of each type of implant in each side of the mandible). A resorbable collagen bonier membrane was placed around one pair of implants on each side. The other two implants on each side served as controls. The sites were examined clinically and histologically after 4 or 8 weeks to assess bone regeneration. Sites around experimental hydroxyapatite-coated and grit-blasted implants showed significantly more bone fill than did control sites. In addition to its apparent ability to encourage bone regeneration, the collagen membrane is resorbable obviating the need for a second surgery to allow removal.