The healing response of the periodontium was evaluated after periodontal flap and debridement procedures in patients with different levels of postsurgical plaque control. Thirty-one sites in 19 patients were included. Measurements were performed from a fixed reference point presurgically and before reentry surgery. All reentries were performed 24 to 28 weeks after surgery. Surgery consisted of elevating an inverse bevel mucoperiosteal flap, debriding root accretions and osseous defects, penetrating into the marrow, and suturing with interrupted sutures at or near the presurgical level. All patients were recalled at least once every 4 weeks after surgery fof professional maintenance. The number of postsurgical maintenance visits and plaque scores (NPI) before reentry were recorded for each surgical site. Average pocket depth at the 31 sites was 7.4 mm initially and 4.1 mm at the time of reentry. This reduction in pocket depth consisted of gingival recession, which averaged 2.0 mm, and a gain in attachment level, which averaged 1.4 mm. At no site was there a loss in attachment level. Average osseous depth of the 31 defects was 3.7 mm presurgically and 1.7 mm at reentry. In addition, there was an average crestal resorption of 0.8 mm and an average osseous fill of 1.2 mm. A significant positive correlation (P less than 0.001) was found between gain in attachment, osseous fill and number of postsurgical maintenance visits. A significant negative correlation was found between the amount of plaque (NPI) at the study site and both gain in soft tissue attachment and osseous fill. Multiple measurements at various points within several osseous defects revealed that osseous remodeling and fill varied significantly at different locations within the same defect.