This report details histologic healing responses at intrabony sites within two patients about 1 year after surgery. Treatment consisted of open flat debridement of the lesions. At specific sites, augmenting procedures such as autogenous grafts, allografts, synthetic grafts and citric acid root treatment were utilized. In addition, notches were made through calculus prior to root planing at specific root surfaces. These notches were placed at varying distances from the base of the lesion. Patients were followed postsurgically with frequent maintenance visits. Block sections were removed at the end of the experimental period. Clinical reduction in pocket depth was noted at all treated sites. This reduction consisted of limited pocket closure, marginal gingival recession and repocketing. Histologically, all specimens showed evidence of repair. The most mature repair appeared at sites treated with debridement and autogenous grafts. "Regeneration" of lost periodontal attachment was demonstrated by evidence of cementogenesis, osteogenesis and the presence of functionally oriented ligaments. However, the coronal regeneration appeared spatially limited. Allografts showed a similar, but less mature healing response. Synthetic graft material acted essentially as a "filler" within the defect. Citric acid root treatment did not demonstrate clear evidence of augmentation of the repair process. Of particular note in these human specimens was further histologic demonstration that "regeneration" potential apparently can only take place in close proximity to histologically viable periodontal ligament cells which may act as "donor sites" for coronal "regeneration" of lost periodontal attachment. This histologic response was observed regardless of treatment modalities used.

Eight intrabony lesions in four patients were removed en bloc 3 to 8 months after periodontal flap debridement. At the time of debridement, the position of the gingival margin and the most apically located calculus were notched to serve as reference points. All lesions received "Synthograft" implants and lesions healed uneventfully. Even though these were severely involved periodontal sites, clinical measurements at time of block removal demonstrated gingival recession (average = 2.9 mm) and a gain in clinical closure (average = 2.6 mm). Histologically, graft particles were present in each specimen. They were walled off by collagen and did not appear to enhance new attachment nor did they induce an inflammatory infiltrate. Thus, they seemed to act as nonirritating fillers. Microscopically, closure of the lesions demonstrated repair with limited evidence of new connective tissue attachment. Histologic expression of the clinical gain in closure was the result of closure by long epithelial adhesion (long junctional epithelium) and possible linkage of dentinal collagen with gingival fibers at areas of dentinal resorption. These variations in closure were often seen within the same clinical site.

9 sites of 8 teeth in 5 adults with severe periodontitis were treated by open surgical debridement followed by placement of 1 of 2 Teflon barrier membranes. Teeth were notched at both gingival margins and deepest visible calculus on the root. Barrier membranes were placed apical to alveolar crest and coronal to gingival notch. Flaps were sutured coronally and patients were placed on 1.2% chlorohexodine gluconate twice daily for 2 weeks, post-surgery. Subsequent to suture removal, patients returned for frequent plaque control until block removal. In order to observe early healing responses, 6 sites were harvested 5 to 8 weeks after surgical treatment. 3 additional sites were removed 14, 22 and 30 weeks respectively after surgical treatment. Histologically, new cementum was seen in a linear direction along root surfaces in 6 out of 9 sites (length of cementum = 0.5 to 1.7 mm). 3 sites showed no evidence of new attachment. At sites of cementogenesis, functionally-oriented fibers were inserted. The osseous seams opposite the new attachment often demonstrated osteogenesis. Regenerative responses were seen with both types of teflon membranes and were present as early as 5 weeks after surgery.

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.

Twelve intrabony periodontal lesions in three volunteers received surgical debridement followed by site implantation of porous hydroxylapatite implants. These patients were followed over a total of a 1-year observation period. Blocks of treated sites were surgically removed at 3 months, 6 months and 12 months after implantation. Clinical observation indicated a reduction in pocket depth consisting of both recession and clinical gain of attachment. No ill effects were observed. Histologic examination of the treated sites showed ossification of the implant pores and the implant periphery as early as 3 months after implantation, which became pronounced 12 months after placement. At times, peripheral ossification linked with crestal osseous seams. This ossification occurred in the presence of an adjacent root covering, long junctional epithelium, and thus there was no new attachment. On the other hand, this graft material offers the potential of increasing new bone mass within a human intrabony lesion.