Fenestration Defects Research Articles

Guided bone regeneration for dehiscence and fenestration defects on implants using an absorbable polymer barrier.

Guided bone regeneration (GBR) using a non-absorbable barrier has provided clinicians the ability to place implants in sites compromised by insufficient bone, including immediate extraction sites. Recent evidence suggests that successful GBR outcomes may be possible using bioabsorbable polymer barriers. This report presents a case series of 9 patients with 8 fenestration and 3 dehiscence defects on implants consecutively treated with GBR. A bioabsorbable polymer barrier of poly(DL-lactide) was used in conjunction with a composite graft of freeze-dried bone allograft (FDBA)/demineralized freeze-dried bone allograft (DFDBA) mixed in a ratio of 1:1. Second-stage surgeries were performed at 4 to 8.5 months (5. 7 months average) post-placement. Biopsy material from 2 sites was obtained while exposing the implant for healing abutment connection. Ten of the 11 defects (90.9%) achieved complete coverage of the osseous defects. Histologic evaluations revealed the formation of viable bone, frequently in close amalgamation with residual graft particles. These case reports suggest that a poly(DL-lactide) polymer can be used as a physical barrier with a composite bone replacement graft to achieve successful GBR results of dehiscence/fenestration defects when placing implants.

Healing Effects of Demineralized Freeze-Dried Bone Allograft and Deproteinized Bovine Bone Mineral on Periodontal Fenestration Defect in Rats

Healing Effects of Demineralized Freeze-Dried Bone Allograft and Deproteinized Bovine Bone Mineral on Periodontal Fenestration Defect in Rats

Regenerative Effects of Alloplastic Grafts in Rat Periodontal Fenestration Defects

Regenerative Effects of Alloplastic Grafts in Rat Periodontal Fenestration Defects

Chitosan film enriched with an antioxidant agent, taurine, in fenestration defects.

A natural polysaccharide, chitosan (poly-N-acetyl glucosaminoglycan), which is a nontoxic and bioabsorbable polymer, has been shown to have hemostatic and antibacterial effects. An amino acid, taurine, is considered to be beneficial for regulating the inflammation process. The purpose of this study was to investigate the synergistic effects of taurine and chitosan in the experimental defects at the vestibular bone of maxillary canine teeth in six dogs. Chitosan films were prepared as delivery system with or without taurine and placed in the randomly chosen defects. Biopsies were performed on the postoperative seventh day and routine histological procedures were performed for light and electron microscopic evaluations. For each group, 30 different microscopic areas were examined and the numbers of macrophages and neutrophils in these areas were counted. The mean numbers of both macrophages and neutrophils were found statistically different between the chitosan film incorporated with taurine and free chitosan groups (p < 0.0001 p > 0.05). In addition to the increase in cell counts in both groups, the cytological alterations were more obvious in the chitosan film group incorporated with taurine. Accordingly, taurine appears to enhance the acceleration effect of chitosan on wound healing at early periods. This effect could be considered beneficial in tissue repair in destructive diseases like periodontitis.

Clinical and radiographic evaluation, following delivery of fixed reconstructions, at GBR treated titanium fixtures.

Conditions following incorporation of fixed reconstructions, at endosseous titanium implants augmented at local bony dehiscence and fenestration defects using a bioabsorbable Resolut membrane were studied in 7 patients. Fixture stability, radiographic marginal bone levels and peri-implant soft tissue status were evaluated at 21 membrane treated and 17 control fixtures (installed in regions of adequate bone volume), following a 2-year period of functional loading. Prosthetic reconstructions were removed and clinical examination and Periotest values revealed that all fixtures were stable. All peri-implant soft tissues were clinically healthy. The mean probing depths at buccal sites for fixtures with original dehiscence (n = 10) and fenestration (n = 11) defects were 1.6 +/- 0.7 mm and 1.2 +/- 0.4 mm respectively. The control fixture group had a mean buccal probing depth of 1.4 +/- 0.6 mm. At abutment connection radiograph membrane treated fixtures had significantly lower marginal bone levels than control fixtures, indicating that optimal bone regeneration was not achieved at all defects. Mean radiographic bone loss 23-27 months following delivery of fixed reconstructions for original dehiscence and fenestration defect fixtures was 0.7 +/- 0.8 mm and 0.8 +/- 0.6 mm respectively at mesial surfaces, and 0.8 +/- 0.7 mm and 0.6 +/- 0.5 mm at distal surfaces. In the control fixture group a mean loss of 0.7 +/- 0.5 mm at mesial surfaces and 0.5 +/- 0.4 mm at distal surfaces was found. Results showed no significant difference in the rate of bone loss following functional loading between membrane treated and control fixtures.

Effect of allogeneic freeze-dried demineralized bone matrix on regeneration of alveolar bone and periodontal attachment in dogs.

This split-mouth study was designed to evaluate regeneration of alveolar bone and periodontal attachment following implantation of allogeneic, freeze-dried, demineralized bone matrix (DBM). Buccal fenestration defects (6x4 mm) were created on the maxillary canine teeth in 6 beagle dogs. DBM was implanted into one randomly selected defect in each animal. The contralateral defect served as surgical control. Tissue blocks were harvested following a 4-week healing interval and prepared for histometric analysis. DBM was discernible in all implanted defects with limited evidence of bone metabolic activity. The DBM particles appeared invested within a dense connective tissue, often in close contact to the instrumented root. Fenestration defect height averaged 3.8+/-0.1 and 3.7+/-0.3 mm, total bone regeneration 0.9+/-0.9 and 0.4+/-1.2 mm, and total cementum regeneration 2.3+/-1.5 and 0.6+/-0.7 mm for DBM and control defects, respectively. Differences with regards to cementum regeneration were statistically significant (p=0.03). In summary, the results of this study suggest that DBM implants may enhance cementum regeneration in this defect model, and that they have no apparent effect on alveolar bone regeneration. Enhanced cementum regeneration may be possibly be explained by provisions for guided tissue regeneration from the implant suppressing a significant influence of the gingival connective tissue on the healing process. Moreover, a 4-week healing interval appears insufficient for turnover of DBM.

Effect of allogenic freeze-dried demineralized bone matrix on guided tissue regeneration in dogs.

This randomized, split-mouth study was designed to evaluate the adjunctive effect of allogenic, freeze-dried, demineralized bone matrix (DBM) to guided tissue regeneration (GTR). Contralateral fenestration defects (6 x 4 mm) were created 6 mm apical to the buccal alveolar crest on maxillary canine teeth in 6 beagle dogs. DBM was implanted into one randomly selected fenestration defect. Expanded polytetrafluoroethylene (ePTFE) membranes were used to provide bilateral GTR. Tissue blocks including defects with overlying membranes and soft tissues were harvested following a four-week healing interval and prepared for histometric analysis. Differences between GTR+DBM and GTR defects were evaluated using a paired t-test (N = 6). DBM was discernible in all GTR+DBM defects with limited, if any, evidence of bone metabolic activity. Rather, the DBM particles appeared solidified within a dense connective tissue matrix, often in close contact to the instrumented root. There were no statistically significant differences between the GTR+DBM versus the GTR condition for any histometric parameter examined. Fenestration defect height averaged 3.7+/-0.3 and 3.9+/-0.3 mm, total bone regeneration 0.8+/-0.6 and 1.5+/-0.8 mm, and total cementum regeneration 2.0+/-1.3 and 1.6+/-1.7 mm for GTR+DBM and GTR defects, respectively. The histologic and histometric observations, in concert, suggest that allogenic freeze-dried DBM has no adjunctive effect to GTR in periodontal fenestration defects over a four-week healing interval. The critical findings were 1) the DBM particles remained, embedded in dense connective tissue without evidence of bone metabolic activity; and 2) limited and similar amounts of bone and cementum regeneration were observed for both the GTR+DBM and GTR defects.

Does root surface conditioning with citric acid delay healing?

Effects of topical citric acid application on tissue maturation was studied in standardized periodontal defects in 6 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and recessed 0.5 mm into the dentin of maxillary canines. 1 defect in each dog was conditioned with a saturated solution of citric acid for 3 min and then rinsed with saline. Control defects in contralateral teeth were treated with saline only for the same length of time. The defects were covered with an expanded polytetrafluoroethylene membrane and the flaps repositioned and sutured. 14 days postsurgery, healing appeared more advanced along the defect walls and floor than in the center of the defect in all instances. Histometrically, citric acid-conditioned defects exhibited a higher density of collagen fibers along the defect walls and floor and adjacent to the barrier membrane as well as more advanced resolution of the residual blood clot than the surgical controls. Differences in fibroblast density within specimen pairs were non-significant. All control defects but none of the acid-conditioned defects showed an artifactual split between the dentin walls and the granulation tissue. This study failed to support the contention that topical application of citric acid to root surfaces may delay healing following periodontal surgery.

Collagen gel and membrane in guided tissue regeneration in periodontal fenestration defects in dogs

The effect of a collagen gel matrix as a submembranous space-maintaining material was evaluated in guided tissue regeneration procedures. In 4 dogs, contralateral surgical circular fenestration defects, 5 mm in diameter, were produced at the midbuccal aspect of the alveolar bone in 8 maxillary canines. Removal of bone, PDL and cementum was complete. Experimental sites were filled with collagen gel and covered with collagen membranes; control sites were covered with collagen membranes and the underlying space was spontaneously filled with blood. Mucogingival flaps were repositioned. Histological and histomorphometric observations, 6 weeks post-surgery, indicated that defects covered by collagen membranes presented the most impressive regeneration with almost complete coverage of the denuded root by new cementum (98.4%) and new bone (63.2%). In the experimental defects, 83.5% coverage of new cementum with only 21.9% new bone regeneration was observed. These results suggest that collagen gel, interfered with healing by PDL and bone-derived cells in the submembranous space.

Impaired early bone formation in periodontal fenestration defects in dogs following application of insulin-like growth factor (II). Basic fibroblast growth factor and transforming growth factor beta 1.

Effects of a topically applied growth factor combination on fibroblast migration, collagen fiber formation and bone regeneration were studied in standardized periodontal defects in 4 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and into the dentin of maxillary and mandibular teeth. Collagen sponges, impregnated with 200 ng insulin-like growth factor II, 20 ng basic fibroblast growth factor and 6 ng transforming growth factor beta 1 were fitted to defects randomly in right or left quadrants and the flaps repositioned and sutured. Contralateral control defects received the collagen with vehicle only. Experimental procedures were staggered to allow observations of healing 3, 7, 10, and 14 days after surgery. Histometric analysis showed no differences in fibroblast and collagen density between control and growth factor defects. Bone regeneration was significantly greater in control than in growth factor defects 10 and 14 days after surgery. The rate of healing generally appeared more affected by intra-dog variations or procedural variations than by the growth factor combination.

The Effect of Platelet‐Derived Growth Factor on the Cellular Response of the Periodontium: An Autoradiographic Study on Dogs

Platelet-derived growth factor (PDGF) is a polypeptide growth factor considered to have a role in the proliferation and migration of fibroblasts at a wound healing site. The aim of this investigation was to determine if PDGF, when applied to root surfaces, would stimulate the proliferation of fibroblasts and further enhance regeneration. Six mongrel dogs with healthy periodontia were selected for this study. Using a closed wound surgical model, standardized 4 x 4 mm fenestration defects were created into dentin on the mid-facial of the mesial and distal roots of 4 mandibular posterior teeth in each quadrant. Each defect received either: 1) saline solution (C); 2) expanded polytetrafluoroethylene (ePTFE) membrane; 3) PDGF; or 4) ePTFE + PDGF. 3H-thymidine was administered 1 hour prior to animal sacrifice at 1, 3, and 7 days postsurgery. Each time period included 2 dogs with each dog undergoing the four different treatments. Slides were prepared for autoradiography. 3H-thymidine-labeled cells were counted and results were statistically analyzed using the Bonferroni (Dunn) t test on the SAS program. Results indicated PDGF enhanced fibroblast proliferation when compared to the groups without PDGF. Significant differences (P < 0.05) were noted at day 1 and 7 when PDGF and PDGF + GT were compared to C and GT groups. No significant differences were observed in labeled fibroblasts between the C and GT groups at any time period. These findings suggest that PDGF enhances fibroblast proliferation in early periodontal wound healing, whether used alone or in combination with the ePTFE membrane.

Effect of a collagen matrix on healing in periodontal fenestration defects in dogs.

Contralateral periodontal fenestration defects in seven beagle dogs were used to evaluate influence of a collagen matrix on periodontal wound healing. The defects (6 x 4 mm) were created through the buccal cortical plates of the maxillary canine teeth following elevation of mucoperiosteal flaps. The collagen was fitted to the defects on one side. Contralateral defects served as controls. Flaps were repositioned and sutured. Dogs were sacrificed 4 weeks after surgery and block sections including teeth and surrounding structures were prepared for histometric analysis. No meaningful differences in cementum and bone regeneration were observed between treatments. There was seemingly more bone regeneration in the apical than in the coronal aspect of the defects and significantly more cementum regeneration. Root resorption was observed in one collagen and one control defect. Ankylosis was not observed. The results suggest that the maxillary canine periodontal fenestration defect can be used as a model to evaluate factors that may enhance cementum and bone regeneration. The collagen matrix neither enhanced nor inhibited periodontal wound healing in this model.

Comparative pathology of periodontal disease: I. Gorilla

A total of 292 gorilla skulls were examined for periodontal disease as evidenced by resorptive lesions of the alveolar bone. Osseous periodontal lesions consisting of horizontal resorption, furcation involvements, interproximal craters, fenestrations, and buccal vertical defects were observed in 76.4 per cent of the specimens. The roots of the maxillary first molar appeared to be most often involved with a fenestration defect. Measurements of the alveolar bone lesions appear to indicate that a severe vertical loss of buccal bone (dehiscence may result from a confluence of the increasing horizontal and fenestration types of alveolar bone resorption.