This multistage study, using nationally made membranes, evaluated periodontal regeneration capacity, in mongrel dogs with indigenous periodontal disease. Following divided mouth experimental design, as validated by Wikesjo etal. (102) applied to the inferior arch, an experimental and a control side were taken, choosing the second and third premolars as work zones. On the experimental side, a nationally made membrane was placed overthe furcal defect, following prior scraping and root isolation; in as muchas the control defect had no membrane placed over it, being only scraped and the root isolaied. Membranes were removed between thefoutth and sixth post-implantation week. Results were as follows: 1) Clinically, an average 4.4 mm insertion gain was obtained at experimental sites, whereas the average gain at control sites was 3.5 mm. 2) On average, a 62.85% reduction in experimental defect depth was obtained, while control depth reduction was 51.42%. 3) Histometrically, there was 3.35 mm cement and periodontal ligament neoformation, corresponding to 47.85% on the experimental side, whereas an average 3.08 mm was recorded for controls, corresponding to 44%; bone neoformation average was 2.36 mm (33.71%) for experimental sites and 1.6 mm (22.85%) for control sites. Histologically, there was measurable root cement neoformation, new periodontal ligament and bony neoformation around the depth of the defect at experimental as well as control sites; however the response was statistically greater, on average, at sites with membrane. The enormous variation when evaluating individual responses attracts attention, finding that in come cases with membrane the result was very poor whereas in others it was excellent; the same phenomena being observed at control sites.