Extraction of the failing teeth will be performed atraumatically; a mucoperiosteal flap will not be employed. After removal of the tooth, the alveolus will be meticulously debrided and cleaned. In the test site, the socket will be filled with xenograft and a collagen membrane. In the control site, no graft material or collagen membrane will be used. Clinical measurements, standardized peri-apical radiographs and Cone Beam Computed Tomography scans will be performed immediately following tooth extractions (visit 2) and 6 months (visit 4) after extractions.