AbstractTwo infrabony defects (i.e. defects in tooth supporting bone that extend into the body of the bone) in different sites in the same individual were treated surgically. Tissue regeneration was incorporated into the surg-ical procedures using a different material in each site (oxidized cellulose mesh and bioglass). The post surgical radiographic appearance showed increasing calcification in both sites that was not complete even at 15 months after placement. The radiographic appearance of both sites was similar but calcification was observed above the crest of alveolar bone in the oxidized cellulose mesh site that was not present with bioglass site. As calcification did not appear to be complete by 15 months after place-ment and it did not resemble true bone in either site, it would appear that the regenerative process was not yet complete by this time. Bone regeneration may therefore progress slowly over a protracted period of time after placement. Some evidence is present that oxidized cellulose mesh may have enhanced regenerative capacity by comparison to other synthetic bone regeneration materials such as hydroxyapatite and bioglass. No conclusions could be drawn from this single case study and further work is necessary to confirm and investigate these observations more fully.