Retardation of epithelial migration in new attachment attempts in intrabony defects in monkeys

Abstract New attachment procedures were performed in 80 three-wall intrabony defects produced adjacent to incisors and canines in monkeys. Following a reverse bevel incision, rnucoperiosteaS flaps were raised on the buccal and lingual aspect of 40 intrabony defects, AH soft tissue was removed from the defects and following transplantation of autogenous bone grafts, the tissue flaps were replaced and sutured. On the buccal and lingual aspect of another 40 intrabony defects a split flap procedure was performed. Granulation tissue was removed from the defects and following transplantation of autogenous bone grafts, the defects were covered with free palatal grafts. The animate were sacrificed (o yield observation periods from 0 to 42 days. After de-caicification of the specimens and embedding in paraffin, 8-μm serial sections were cut and stained. The epithelium on the full thickness flap seemed almost unaffected by the surgical procedure and had migrated between 0.2 mm and 2.0 mm along the root surface during the first week of healing. The epithelium on the transplants degenerated almost completely within the first week after surgery and epithelial migration along the root surface was not observed until after 10–12 days. These results indicate that the migration of epithelium during the postoperative phase of new attachment attempts can be retarded by covering the defects with free palatal grafts instead of full thickness flaps.     

Reconstructive periodontal therapy with simultaneous ridge augmentation. A clinical and histological case series report

Treatment of intrabony periodontal defects with a combination of a natural bone mineral (NBM) and guided tissue regeneration (GTR) has been shown to promote periodontal regeneration in intrabony defects. In certain clinical situations, the teeth presenting intrabony defects are located at close vicinity of the resorbed alveolar ridge. In these particular cases, it is of clinical interest to simultaneously reconstruct both the intrabony periodontal defect and the resorbed alveolar ridge, thus allowing insertion of endosseous dental implants. The aim of the present study was to present the clinical and histological results obtained with a new surgical technique designed to simultaneously reconstruct the intrabony defect and the adjacently located resorbed alveolar ridge. Eight patients with chronic advanced periodontitis displaying intrabony defects located in the close vicinity of resorbed alveolar ridges were consecutively enrolled in the study. After local anesthesia, mucoperiosteal flaps were raised, the granulation tissue removed, and the roots meticulously scaled and planed. A subepithelial connective tissue graft was harvested from the palate and sutured to the oral flap. The intrabony defect and the adjacent alveolar ridge were filled with a NBM and subsequently covered with a bioresorbable collagen membrane (GTR). At 11-20 months (mean, 13.9+/-3.9 months) after surgery, implants were placed, core biopsies retrieved, and histologically evaluated. Mean pocket depth reduction measured 3.8+/-1.7 mm and mean clinical attachment level gain 4.3+/-2.2 mm, respectively. Reentry revealed in all cases a complete fill of the intrabony component and a mean additional vertical hard tissue gain of 1.8+/-1.8 mm. The histologic evaluation indicated that most NBM particles were surrounded by bone. Mean new bone and mean graft area measured 17.8+/-2.8% and 32.1+/-8.3%, respectively. Within their limits, the present findings indicate that the described surgical approach may be successfully used in certain clinical cases to simultaneously treat intrabony defects and to reconstruct the resorbed alveolar ridge.     

Clinical and histologic evaluation of human intrabony defects treated with an enamel matrix protein derivative combined with a bovine-derived xenograft

The purpose of the present case report study was to clinically and histologically evaluate the healing of deep intrabony defects following treatment with either a combination of an enamel matrix protein derivative (EMD) and a bovine-derived xenograft (BDX) or with BDX alone. Three female patients with generalized marginal periodontitis and presenting one advanced intrabony defect each were treated with either a combination of EMD + BDX (two defects) or with BDX alone (one defect). The postoperative healing was uneventful in all three cases. Six months after surgery, a gain of clinical attachment was measured at all treated sites. The histologic examination revealed that all three defects healed with a new connective tissue attachment (ie, new cellular cementum with inserting collagen fibers) and new bone. Most of the BDX particles were surrounded by a bone-like tissue. No direct contact between BDX particles and the root surface (cementum or dentin) was observed. Within their limits, the present data indicate that treatment with either EMD + BDX or with BDX alone may enhance the formation of new connective tissue attachment and new bone in human intrabony defects.     

Histologic evaluation of new attachment apparatus formation in humans. Part III

There is still controversy as to the role of bone grafting materials in the formation of a new attachment apparatus and component tissues (bone, cementum, and periodontal ligament). The purpose of this study was to compare the healing of intrabony defects with and without the placement of decalcified freeze-dried bone allograft (DFDBA) in a nonsubmerged environment in humans. The most apical level of calculus on the root served as a histologic reference point to delineate root surfaces exposed to the oral environment and to measure new attachment apparatus and new component tissue formation. Free gingival grafts were placed over grafted and nongrafted defects to retard epithelial migration. Biopsies were obtained at 6 months and regeneration was evaluated histometrically. Data from 12 patients with 32 grafted and 25 nongrafted defects were submitted for statistical analysis. Results indicate that in nongrafted defects, a long junctional epithelium formed along the entire length of exposed root surfaces and often extended apical to the calculus reference notch. Free gingival grafts did not enhance regeneration of a new attachment apparatus, new cementum, new connective tissue, or new bone in nongrafted defects. The formation of a new attachment apparatus was observed when intrabony defects were grafted with DFDBA (x1.21 mm); significantly more new attachment apparatus (P less than .005), new cementum (P less than .005), new connective tissue (P less than .05), and new bone (P less than .0001) formed in intrabony defects grafted with DFDBA than in nongrafted defects. There was a greater chance for regeneration of a new attachment apparatus and component tissues in grafted defects than in nongrafted defects. New cellular cementum formed on old cementum and dentin but more often formed over both in the same defect). The periodontal ligament was more frequently oriented perpendicular to the root; there was greater loss in alveolar crest height in nongrafted than grafted defects (P less than .05); and extensive root resorption, ankylosis, and pulp death were not observed in grafted or nongrafted defects.     

Histologic evaluation of new attachment apparatus formation in humans. Part II

There is conflicting evidence regarding the value of graft materials in enhancing the formation of new bone, cementum, and periodontal ligament (new attachment apparatus). Part II of this study compared the healing of intrabony defects with and without the placement of decalcified freeze-dried bone allograft (DFDBA) in a submerged environment. The most apical level of calculus on the root served as a histologic reference point to measure regeneration on root surfaces exposed to the oral environment. Biopsies were obtained at 6-months and evaluated histometrically by two investigators unaware of the treatment performed. Data from 9 patients with 30 grafted defects and 13 nongrafted defects were submitted for statistical analysis. Results indicate that in a submerged environment significantly more new attachment apparatus (P less than .05) and new bone (P less than .05) formed in grafted than nongrafted sites. Significantly greater loss of alveolar crest height occurred in nongrafted than grafted defects (P less than .05); regeneration of new attachment apparatus, new bone, and new cementum occurred more frequently in grafted than nongrafted defects. There was a greater chance for the regeneration of a connective tissue attachment in nongrafted intrabony defects than in grafted defects; new cellular cementum formed equally well on old cementum, dentin, or both old cementum and dentin in the same defect. The periodontal ligament was oriented parallel, perpendicular, or both parallel and perpendicular in the same defect; and, no extensive root resorption, ankylosis, or pulp death was observed in grafted or nongrafted defects.     

Histologic evaluation of root coverage obtained with GTR in humans: a case report

The purpose of this study was to histologically evaluate four teeth with recession defects that were treated with guided tissue regeneration (GTR). The amount of root coverage obtained ranged from 16.7% to 50.0%. In one of the defects treated, new bone was formed but none of the new bone was coronal to the original gingival margin. Additionally, in this one case new cementum and connective tissue attachment was formed. However, because the new bone, new cementum, and new connective tissue were not coronal to the original gingival margin, this result could not be classified as regeneration. The vast majority of the attachment in this defect was long junctional epithelial attachment in the portion of the recession defect covered by the root-coverage procedure. In the other three defects treated, there was a loss of bone. All of the root coverage obtained was a long junctional epithelial attachment in three of the four defects. The results of this study do not show regeneration in any of the four defects treated.     

Reconstruction of anatomically complicated periodontal defects using a bioresorbable GTR barrier supported by bone mineral. A 6-month follow-up study of 6 cases

Abstract . 6 anatomically complicated periodontal intrabony defects in 6 patients were surgically reconstructed using a bioresorbable GTR barrier supported by cancellous bovine bone mineral. Following cause-related periodontal treatment, open-flap surgery was performed to expose the defects. After debridement, the defects were filled with the bone mineral and covered with the barrier. All patients were advised to rinse 2× daily with an 0.2% chlorhexidine digluconate solution and to avoid brushing in the operated area for 6 weeks. The treatment results were evaluated clinically and radiographically 6 months after surgery. All defects healed uneventfully and all patients maintained a high standard of plaque control throughout the study. Probing assessments during surgery showed a bone defect depth and width of on average 7.2 and 2.8 mm. The corresponding measures on presurgical intra-oral radiographs were 7.9 and 2.6 mm, respectively. Clinical attachment level (CAL) gain averaged 5.3 mm, corresponding to 73% of the original bone defect depth. Radiographically, the defect fill averaged 6.2 mm or 80% of the original radiographic bone defect. It was concluded that the placement of bovine bone mineral beneath bioresorbable GTR barriers facilitates the clinical handling of the barrier and enhances the space for potential periodontal reconstruction of anatomically complicated defects. It remains, however, to be ascertained to what degree the achieved clinical and radiographic results reflect a gain in new connective tissue attachment and alveolar bone.     

Defect-determined regenerative options for treating periodontal intrabony defects in baboons

BACKGROUND: In an effort to regenerate periodontal intrabony defects, the healing potential of the defect should determine what therapeutic modalities and materials are employed. The purpose of this study was to compare regenerative outcomes in baboon intrabony defects that were contained versus non-contained, using various regenerative therapies. METHODS: Nine adult baboons (Papio anubis) in good health were treated. Eighty-six interproximal, intrabony defects were surgically created: 43 contained by 3 walls of bone; 43 non-contained with a missing buccal wall. Chronicity and plaque accumulation were encouraged with wire ligature placement for 8 weeks. After ligature removal, scaling, and a 2- to 4-week healing period, the defects were treated with the following therapies: collagen membrane (GTR), human demineralized freeze-dried bone (DFDB) grafting (BG), combined therapy (GTR + BG) and a DFDB-glycoprotein sponge matrix (MAT). Clinical healing responses were evaluated in 58 sites by changes in soft tissue (recession, probing, clinical attachment) and hard tissue (resorption, defect fill) parameters 6 months post-treatment. Histologic evaluation (defect regeneration, connective tissue attachment, epithelial migration) was done on 26 sites. RESULTS: For contained defects, no real significant clinical (ANOVA) or histologic differences existed among treatments. However, for non-contained defects, combined therapy (GTR + BG) demonstrated clinically significant (P < or = 0.05, ANOVA) and histologically superior healing results over the other therapies tested. CONCLUSION: These results confirm a defect morphology directed rationale for periodontal intrabony therapy.     

A controlled re-entry study on the effectiveness of bovine porous bone mineral used in combination with a collagen membrane of porcine origin in the treatment of intrabony defects in humans

AIM: The purpose of this study was to evaluate the clinical effectiveness of a bovine porous bone mineral used in combination with a porcine derived collagen membrane as a barrier in promoting periodontal regeneration in intrabony defects in humans. MATERIAL AND METHODS: The study employed a split-mouth design. 22 paired intrabony defects were treated and surgically re-entered 6 months after treatment. Experimental sites were grafted with bovine porous bone mineral and received a collagen membrane for guided tissue regeneration. Control sites were treated with an open flap debridement. RESULTS: Preoperative pocket depths, attachment levels and trans-operative bone measurements were similar for control and experimental sites. Post surgical measurements revealed a significantly greater reduction in pocket depth (differences of 1.89 +/- 0.31 mm on buccal 0.88 +/- 0.27 mm on lingual measurements) and more gain in clinical attachment (differences of 1.51 +/- 0.33 mm on buccal and 1.50 +/- 0.35 mm on lingual measurements) in experimental sites. Surgical reentry of the treated defects revealed a significantly greater amount of defect fill in favor of experimental sites (differences of 2.67 +/- 0.91 mm on buccal and 2.54 +/- 0.87 mm on lingual measurements). CONCLUSIONS: The results of this study indicate that clinical resolution of intrabony defects can be achieved using a combination of bovine porous bone mineral and an absorbable, porcine derived collagen membrane when employing a technique based on the principles of guided tissue regeneration. The nature of the attachment between the newly regenerated tissue and the root surfaces needs to be evaluated histologically to confirm the presence of new attachment.     

Human histologic evaluation of an intrabony defect treated with enamel matrix derivative, xenograft, and GTR

The purpose of the present case report is to clinically and histologically evaluate the healing of one advanced intrabony defect following treatment with an enamel matrix protein derivative (EMD) combined with a bovine-derived xenograft (BDX) and guided tissue regeneration (GTR). One patient with generalized chronic periodontitis and one advanced intrabony defect was treated with EMD + BDX + GTR. Notches were placed in the root at the level of the calculus and alveolar crest to aid histologic identification of new periodontal tissues. Postoperative healing was uneventful. At the 7-month histologic examination, healing in the intrabony component of the defect was characterized by formation of new connective tissue attachment (new cellular cementum with inserting collagen fibers) and new bone in the intrabony component. The BDX particles were surrounded by bone-like tissue. No direct contact between the graft particles and root surface (cementum or dentin) was observed. Healing in the suprabony defect component occurred through epithelial downgrowth that stopped at the level of the coronal notch. The BDX particles were entirely encapsulated in dense connective tissue, without any signs of bone formation. The present case report shows formation of new attachment apparatus consisting of new bone, cementum, and periodontal ligament in the intrabony component of one human defect treated with EMD + BDX + GTR.     

Restoration of Periodontal Attachment Employing Enriched Collagen Solution in the Dog

Three wall intrabony defects were produced in 11 dogs using a round bur followed by curettes and hoes. A copper band was fixed to the tooth with stainless steel ligature wire. Six weeks later, the copper band was removed and the defect was treated with an enriched collagen solution (ECS) prepared from acid-extracted dog skin collagen. Thirty-three defects were treated with ECS and 33 defects were controls. Healing was assessed histologically 4 and 6 weeks after treatment for the presence of new cementum, periodontal ligament and alveolar bone, as well as arrested epithelial downgrowth along the dental root. Unlike the controls, treatment with ECS resulted in restoration of periodontal attachment after 4 weeks. This included formation of new cementum, new alveolar bone and dense connective tissue fibers running between bone and cementum. Control sections showed epithelial migration along the root, separating it from the adjacent connective tissue and thus preventing new attachment.     

Periodontal response after tooth movement into intrabony defects

The present study was undertaken since conflicting evidence exists regarding the effect of such tooth movement on levels of connective tissue attachment. Localized intrabony pockets were produced around isolated incisors in four rhesus monkeys. The root surfaces were planned to the level of the bone at the base of the angular bony defects. An oral hygiene regime was begun and continued for the remainder of the study. The experimental teeth were moved orthodontically into, and through, the original area of the intrabony defect. Two months after cessation of active tooth movement, block specimens were removed for histologic analysis. Control specimens comprised those teeth with induced periodontal defects, but without tooth movement. In specimens not subjected to tooth movement, angular bony defects were present and epithelium lined the root surface to the apical extent of instrumentation. The alveolar bone adjacent to the orthodontically moved teeth no longer had angular defect morphology. On the pressure side, epithelium lined the root surface, was interposed between root surface and bone and terminated at the apical limit of root instrumentation. On the tension side, the crest of the bone was located apical to the level of root planing, and epithelium lined the instrumented portion of the root surface. It was concluded that orthodontic tooth movement into intrabony periodontal defects was without effect upon the levels of connective tissue attachment.     

A comparative study of combined treatment with a collagen membrane and enamel matrix proteins for the regeneration of intraosseous defects

Recent clinical study shows that periodontal regeneration therapy using enamel matrix proteins (Emdogain; EMD) is expected to have the same therapeutic effect as guided tissue regeneration (GTR). However, reports on the combined effect of both therapies are limited, and the clinical significance is not definite. In this study, clinical effects were studied by comparing a combination of EMD and GTR using a collagen membrane for intrabony defects with GTR monotherapy and EMD monotherapy. Sixty-one patients with 69 intrabony defects were included. Efficacy of treatment was evaluated at 6 months and 1 year by assessment of reduction of probing depth, probing attachment gain, and radiographic bone gain. There were no statistically significant differences between presurgical soft tissue measurements and defect characteristics for the three treatment groups. The results showed no significant differences in reduction of probing depth, probing attachment gain, or radiographic bone gain between the three treatment groups at both evaluation times. The combination of GTR using a resorbable membrane for intrabony defects and EMD did not enhance the therapeutic effect compared with each monotherapy.     

A reentry study on the use of bovine porous bone mineral, GTR, and platelet-rich plasma in the regenerative treatment of intrabony defects in humans

This study compared the clinical effectiveness of a combination therapy consisting of bovine porous bone mineral (BPBM), guided tissue regeneration (GTR), and platelet-rich plasma (PRP) in the regeneration of periodontal intrabony defects in humans. Twenty-eight paired intrabony defects were surgically treated using a split-mouth design. Defects were treated with BPBM, GTR, and PRP (experimental), or with open-flap debridement (control). Clinical parameters evaluated included changes in attachment level, pocket depth, and defect fill as revealed by reentry at 6 months. Preoperative pocket depths, attachment levels, and transoperative bone measurements were similar for the two groups. Postsurgical measurements taken at 6 months revealed that both treatment modalities significantly decreased pocket depth and increased clinical attachment and defect fill compared to baseline. The differences between the experimental and control groups were 2.22+/-0.39 mm on buccal and 2.12+/-0.34 mm on lingual sites for pocket depth, 3.05+/-0.51 mm on buccal and 2.88+/-0.46 mm on lingual sites for gain in clinical attachment, and 3.46+/-0.96 mm on buccal and 3.42+/-0.02 mm on lingual sites for defect fill. These differences between groups were statistically significant in favor of the experimental defects. The combined therapy was also clinically more effective than open-flap debridement. The superiority of the experimental group could not be attributed solely to the surgical intervention and was likely a result of the BPBM/GTR/ PRP application. Combining BPBM, GTR, and PRP was an effective modality of regenerative treatment for intrabony defects in patients with advanced periodontitis.     

The effectiveness of enamel matrix proteins used in combination with bovine porous bone mineral in the treatment of intrabony defects in humans

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of enamel matrix proteins (EMPs) used in combination with bovine porous bone mineral (BPBM), compared to open flap debridement (OFD) in the treatment of intrabony defects in humans. MATERIAL AND METHODS: Using a split-mouth design, 24 paired intrabony defects were surgically treated and re-entered 6 months later. Experimental sites were treated with EMPs and grafted with BPBM. Control sites were treated with an OFD. The primary outcomes evaluated in the study were changes in pocket depth, clinical attachment level and defect bone fill. RESULTS: Preoperative pocket depths, attachment levels and intra-operative bone measurements were similar for control and experimental sites. 6-month post surgical measurements revealed a significantly greater reduction in pocket depth (differences of 2.35+/-0.86 mm on buccal and 2.28+/-0.90 mm on lingual measurements) and more gain in clinical attachment (differences of 2.04+/-0.28 mm on buccal and 1.99+/-0.26 mm on lingual measurements) in the experimental sites. Surgical reentry of the defects revealed a significantly greater amount of defect fill in favor of the experimental sites (differences of 2.85+/-0.28 mm on buccal and 2.67+/-0.33 mm on lingual measurements). CONCLUSIONS: The results of this study suggest that combining EMPs and BPBM as a regenerative technique for intraosseous defects results in statistically and clinically significant more favorable results than OFD. The nature of the attachment between the newly regenerated tissue and the root surfaces needs to be evaluated histologically to confirm the presence of new attachment.     

Clinical and histologic evaluation of a granular bovine bone biomaterial used as an adjunct to GTR with a bioresorbable bovine pericardium collagen membrane in the treatment of intrabony defects

Background: The aim of the present study is to evaluate the clinical and histologic healing of deep intrabony defects treated with guided tissue regeneration (GTR) with a collagen membrane from bovine pericardium and implantation of granular bovine bone biomaterial. Methods: Thirty patients with one deep, combined 1‐ and 2‐wall intrabony defect exhibiting a probing depth ≥6 mm and an associated intrabony defect ≥3 mm were treated with GTR with a bioresorbable collagen membrane from bovine pericardium and adjunct implantation of a granular bovine bone biomaterial. The clinical results were evaluated 1 and 3 years after surgery. In addition, five teeth fulfilling the inclusion criteria but scheduled for extraction because of advanced periodontitis or restorative considerations were treated similarly and then extracted along with a portion of their surrounding periodontal tissues for histologic evaluation 6 months after surgery. Results: Healing was uneventful in all patients. Significant clinical improvements were observed at 1 and 3 years postoperatively (P <0.01; probing depth averaged 4.4 ± 1.6 and 4.7 ± 1.4 mm and clinical attachment level gain was 3.9 ± 1.4 and 3.5 ± 1.3 mm, respectively). The histologic evaluation revealed formation of new cellular cementum and new periodontal ligament in four of the five cases. In general, the xenograft particles seemed to be mostly embedded in connective tissue without any evidence of new bone formation. Conclusion: GTR treatment of intrabony defects with the collagen membrane from bovine pericardium and adjunct implantation of the new bovine bone biomaterial may result in significant clinical improvements that can be maintained over a period of 3 years, and regeneration of cementum and periodontal ligament, but without bone formation.     

Clinical and histologic evaluation of human intrabony defects treated with an enamel matrix protein derivative (Emdogain)

An enamel matrix protein derivative (Emdogain) has been recently shown to promote periodontal regeneration in experimentally created recession-type defects. However, only limited histologic data from human material are available concerning the healing of intrabony periodontal defects following treatment with Emdogain. The aim of the present study was therefore to present the clinical and histologic results following the application of Emdogain in intrabony defects. Two patients with marginal periodontitis and deep intrabony defects adjacent to teeth scheduled for extraction were treated with Emdogain. The postoperative healing phase was uneventful in both cases. At 6 months following treatment, newly formed cementum with inserting collagen fibers was found in both specimens. In one case, the new attachment formation was also accompanied by bone neoformation. The results of this human histologic study indicate that Emdogain possesses the potential to stimulate new connective tissue attachment formation in human intrabony defects.     

New attachment and bone formation in periodontal defects following treatment of submerged roots with guided tissue regeneration

Abstract The purpose of the present study was to examine the effect on periodontal regeneration of preventing bacterial contamination of the membrane material following the guided tissue regeneration procedure (GTR). Periodontal dehiscence defects were surgically produced in 2 monkeys. In each monkey, 8 of these defects were submerged after resection of the crowns of the teeth and a teflon (Gore-Tex Periodontal Material®) or a polyglactin (Vicryl Mesh®) membrane was adjusted to cover the defect and the exposed root surface. 4 defects on non-crown resected teeth were treated with either a teflon or a polyglactin membrane positioned with the coronal border approximately 2 mm below the margin of the covering tissue flap. Following 6 months of healing, the animals were sacrificed. Histological evaluation of the specimens revealed that roots which were kept completely covered during the healing period demonstrated new connective tissue attachment and bone formation corresponding to 67–100% of the length of the initial defect depth, whereas the amount of new connective tissue attachment and bone on non-submerged roots ranged between 30–59% and 11–31%, respectively. It seems reasonable to anticipate that it is bacterial contamination of the membrane material which jeopardizes the formation of new connective tissue attachment but in particular bone formation following the GTR-procedure.     

A case report study of 72 consecutive Emdogain-treated intrabony periodontal defects: clinical and radiographic findings after 1 year

This case report study examined the effect of adjunctive use of Emdogain in the treatment of intrabony periodontal defects. Seventy-two consecutively treated defects in sixty-one patients were included. Efficacy of treatment was evaluated at 12 months by assessment of probing depth reduction, probing attachment level gain, and radiographic bone gain from standardized radiographs. Initial pocket depth averaged 8.3 mm, and the mean probing attachment level was 10.0 mm. The mean radiographic defect depth was 5.3 mm. At 12 months, mean pocket depth reduction was 4.7 mm and mean probing attachment level gain was 4.2 mm. Radiographic bone level gain averaged 3.1 mm and defect fill averaged 70%. The only variables significantly affecting radiographic bone gain were bleeding on probing and smoking. It was concluded that Emdogain treatment of one- and two-walled intrabony defects in a periodontal practice will result in a clinically significant gain of probing attachment level and radiographic bone that is similar to that reported in controlled clinical trials.     

Histologic evaluation of new attachment in humans. A preliminary report

This study was designed to evaluate the potential for regeneration of a new attachment (alveolar bone, cementum and a functional periodontal ligament) in patients whose attachment apparatus had been destroyed by periodontal disease. In each of the three parts of the investigation, the most apical level of calculus on the root served as a histologic reference point to measure regeneration. In Part I, attempts were made to initiate the formation of a new attachment by surgical debridement, crown removal (coronectomy) and submersion of the vital root below the mucosa. Nonsubmerged, surgically debrided defects served as controls. In Part II, debrided intrabony defects were treated with and without demineralized freeze-dried bone allograft and the associated vital roots were submerged. Part III evaluated potential for regeneration of a new attachment in nonsubmerged roots with and without the use of demineralized freeze-dried bone allograft. Gingival grafts were placed over the experimental and control sites in an attempt to retard epithelial migration. Biopsies were obtained in 6 months and regeneration was evaluated histometrically. Preliminary results in 7 patients and 24 intrabony defects indicate that new attachment is possible on pathologically exposed root surfaces in a submerged environment with and without the incorporation of demineralized freeze-dried bone allografts. New attachment was observed on pathologically exposed root surfaces in a nonsubmerged environment when intrabony defects were grafted with demineralized freeze-dried bone allograft. New attachment was not observed on nongrafted, nonsubmerged, defects with and without the placement of gingival grafts over the defects.