Treatment Of Periodontal Defects Research Articles

In Vitro Evaluation of the Mitogenic Effect of Platelet‐Derived Growth Factor‐BB on Human Periodontal Ligament Cells Cultured with Various Bone Allografts

Several studies have documented the role of growth factors in periodontal regeneration. It has been shown that platelet-derived growth factor (PDGF) is a potent stimulator of human periodontal ligament (PDL) cells. A variety of bone graft materials are used to treat osseous defects caused by periodontal disease. We evaluated the mitogenic effect of PDGF on human PDL cells cultured with different allografts to determine which of the allografts with or without PDGF promoted periodontal regeneration. Two human demineralized freeze-dried allografts of cortical (DFDBA) and cancellous (DFBA) bone and a non-demineralized freeze-dried allograft (FBA) from cancellous bone were used alone or supplemented with PDGF-BB. Human PDL cultures were derived from the mid-root of 2 maxillary premolars extracted for orthodontic reasons. Cells were grown separately in 24-well dishes with or without 20 mg of each bone allograft. On day 2 of quiescence, new medium was added with 10 ng/ml of PDGF-BB. DNA synthesis was estimated by measuring [3H] thymidine incorporation to determine the effects of the test agents on cell proliferation. Cells were processed and subjected to scintillation counting after 48 hours of incubation. Counts per minute (cpm/well) were determined for each sample. There was no statistically significant difference (P<0.05) on PDL cell proliferation when the allografts were used alone. PDL cells exhibited significantly greater proliferative responses to the 2 demineralized bone allografts, DFDBA and DFBA, when combined with PDGF-BB. A statistically significant difference on DNA synthesis was noticed when PDGF-BB was added to PDL cells cultured with FBA. PDL cells displayed no significant increase in mitogenic activity when cultured with PDGF-BB alone. The findings of this study demonstrate the beneficial role of DFDBA, DFBA, and FBA as synergic agents with PDGF-BB to periodontal regeneration. The significant ability of the 2 decalcified bone allografts, DFDBA and DFBA, combined with PDGF to stimulate PDL cell proliferation might be a useful adjunct in the treatment of periodontal defects.

Guided tissue regeneration using a polylactic acid barrier.

The purpose of this study was to determine the relative impact of various predictors responsible for the variability in treatment outcome after guided tissue regeneration (GTR) in intraosseous periodontal defects. 30 patients with chronic periodontitis and at least one intraosseous periodontal lesion (> or =4 mm) were enrolled. Following full-mouth scaling, GTR using polylactic acid membranes was performed at one site in each patient. Main periodontal pathogens, defect morphology, membrane exposure and smoking habit were assessed as predictor variables. Alveolar bone level change served as the primary outcome variable in a multiple regression analysis. After 12 months, the 29 patients completing the study showed alveolar bone changes ranging from 4 mm bone gain to 1 mm bone loss (mean: 1.6+/-0.4 mm gain). Active smoking (beta-weight:-0.49, P=0.003) and persistence of subgingival infection with P. gingivalis (P.g.) (beta-weight:-0.25, P=0.11) were associated with poor treatment outcome. Deep initial intraosseous defects (beta-weight: 0.32, P=0.045) were associated with favorable treatment outcome, and membrane exposure had no impact on bone gain. Active smoking was the strongest predictor variable negatively affecting alveolar bone gain following GTR in the treatment of periodontal defects. It was followed by a positive influence of a deeper intraosseous defect and by a negative effect by persistent subgingival infection of P. gingivalis. The relative impact of these factors may be useful in assessing the prognosis of GTR in intraosseous periodontal defects.

LASER DE-EPITHELIALIZATION FOR ENHANCED GUIDED TISSUE REGENERATION: A Paradigm Shift?

The rationale for laser de-epithelialization stems from the attempts to block the down-growth of epithelium into the healing periodontal wound after surgery and prevent formation of a long junctional epithelial attachment. This concept has seen numerous techniques for accomplishing the blockage of epithelium. 7, 19, 28, 37 The advent of GTR was an offshoot of this concept and led Gottlow et al 13 to examine the effects of selectively blocking certain cell types from contacting the root surface during periodontal wound healing. The use of a CO 2 laser to de-epithelialize the gingival flaps is an attempt to exclude this cell type from the healing wound and has been used with and without the benefit of GTR membranes. In a study on beagle dogs, the histologic results of using membranes and the laser procedure enhanced the wound healing and regeneration of new bone, cementum, and connective tissue attachment when compared with paired defects using the membranes alone. 33 The results from the human studies and case reports combined with the animal studies indicate a positive benefit in wound healing because of the laser de-epithelialization technique. The use of an osseous graft in treatment of periodontal defects has been shown to stimulate new bone growth effectively and to regenerate new attachment. 2, 22 It has been speculated that the additional benefit of an osseous graft in GTR procedures is the organization of the blood clot at initial healing, which may tend to maintain the space needed for regeneration and to provide a matrix for the fibrin clot to retard epithelial down-growth. Studies comparing the results of osseous grafting with flap débridement always have shown that the amount of new bone formation and clinical new attachment favor the grafted sites versus paired nongrafted sites. 1, 11, 15, 16 The effects of removal of the pocket epithelium at the time of periodontal surgery have been studied by several authors, 21, 35, 36 and these studies generally show an incomplete removal of the sulcular epithelium by the inverse bevel incision. Epithelial excision was studied by Centty et al, 5 who compared the removal of sulcular epithelium by the CO 2 laser technique with conventional methods. Their results confirm that (1) a more complete removal of sulcular epithelium was obtained by laser than by knives, and (2) the technique effectively removes the oral and sulcular epithelium from a gingival flap without damaging the viability of the flap during wound healing. The technique as described in this article was used by Israel et al 18 to verify further the ability to maintain a viable gingival flap during multiple laser deepithelialization procedures in humans during the first 30 days of healing. The concept of laser de-epithelialization as an adjunct to regenerative periodontal procedures currently is being studied in a multicenter university setting using a parallel study in controlled clinical trials. The first of these reports was mentioned previously (Araujo et al, unpublished data) and shows the enhanced wound healing of periodontal defects through use of the laser de-epithelialization technique. The authors believe that this technique has shown significantly better results than those obtained through conventional osseous grafting alone and appears to be comparable to the results reported for GTR procedures with barrier membranes. This concept provides a paradigm shift from the conventional use of GTR therapy by acknowledging the difficulty in controlling epithelium during the early wound healing. It also allows a more comprehensive therapy for treating periodontal disease that addresses the generalized nature of the disease, with multiple lesions being treated concurrently in an economical manner. The patient presenting with generalized advanced periodontal disease could have several defects definitively treated in one quadrant using the laser deepithelialization technique without the need for multiple membrane therapy. In evaluating the results from 43 patients treated with this technique, it appears that the gain in attachment level rivals those reported from more conventional therapy using membranes. The full benefit of this proposed technique remains to be proved in the clinical setting with further multicentered studies.

D.H. DeForge, VMD

This paper describes the use of Bioglass ® Synthetic Bone Graft Particulate (PerioGlas™ /Consil™ ) in the treatment of osseous periodontal defects, and in post-extraction sites to maintain the vertical height and width of the alveolar ridge. The material is easy to use, inhibits epithelial down-growth, and acts as a mechanical hemostatic agent. Radiographic follow up in 36 dogs and 5 cats demonstrated significant bone fill. In the osseous periodontal defect treatment group, clinical probing depths decreased significantly, and there was an apparent gain in attachment level.

Treatment of Periodontal Defects With an Absorbable Membrane (Polyglactin 910) With and Without Osseous Grafting: Case Reports

The purpose of these reports is to illustrate the possible use of polyglactin 910 as an absorbable membrane for periodontal healing. Eleven surgical sites in 10 patients are reported. Vicryl mesh was used on all sites, and osseous allograft material was used in 8 of these sites. Radiographic evaluation and sounding with anesthesia indicate improvement in the treated areas. Few adverse effects were seen at the treated sites. Therefore, polyglactin offers promise as a material for use in periodontal therapy, especially in deep infrabony pockets. Further controlled studies comparing polyglactin 910 and other resorbable materials as barrier membranes are needed to establish their safety and efficacy.

In vitro properties of a chitosan-bonded hydroxyapatite bone-filling paste

A possible bone substitute material for dental treatment was developed and tested. The material is composed of powdered hydroxyapatite (HA), ZnO and CaO, kneaded into a chitosan sol to make a quick-hardening paste. A composittion was found which showed neutral pH, short setting time, and relatively high compressive strength. The use of such a paste for the treatment of periodontal defects or the augmentation of edentulous alveolar ridges may alleviate problems now associated with the implantation of particulate HA, such as early migration of particles and recontouring of the implant.

Comparison of Freeze–Dried Bone Allograft and Porous Hydroxylapatite in Human Periodontal Defects

This study was conducted to clinically compare the efficacy of freeze-dried bone allograft (FDBA) and porous hydroxylapatite granules. Nineteen pairs of intraosseous defects were grafted in seven patients. One defect of each pair was implanted with FDBA, the other with granular porous hydroxylapatite. Matching defects were treated similarly in all other aspects. Evaluations were based on both preoperative and postoperative measurements from a fixed reference point, standardized radiographs, surgical osseous measurements, and histology of degranulated tissues. Grafted sites were reentered 6 to 11 months postsurgery. Results showed a mean osseous fill of 2.1 mm for FDBA versus 1.3 mm for granular porous hydroxylapatite (P = .07). A mean clinical attachment gain of 2.2 mm for FDBA versus 1.3 mm for granular porous hydroxylapatite (P less than .05), and a mean decrease in probing depths of 3.0 mm for FDBA versus 1.4 mm for granular porous hydroxylapatite (P less than 0.5) was found. FDBA was clinically indistinguishable from host bone, whereas porous hydroxylapatite appeared to be separated from host bone by soft tissue. The data and clinical findings suggested that FDBA may have some enhanced reparative potential when compared to granular porous hydroxylapatite in the treatment of periodontal defects in humans.

Antigenicity of freeze-dried bone allograft in periodontal osseous defects.

Freeze‐dried bone allografts have been used in the treatment of periodontal defects for almost a decade. The present study was undertaken to compare the immunogenicity of freeze‐dried cortical bone allografts with fresh cancellous bone and marrow allografts.Cortical bone from a donor baboon was deep frozen and then freeze‐dried. Cancel lous bone and marrow was removed from the same donor.Angular periodontal osseous defects in the jaws of 2 recipient baboons received freeze‐dried osseous allografts and a third animal received fresh marrow allografts. Three months later the animals received a second identical osseous graft in the arch diagonally opposite the first recipient site.Prior to placing the first grafts and 3 weeks after the second graft was in place 51Cr release assays were done for cytotoxic antibody and cytotoxic lymphocytes to determine if the osseous allograft materials induced immune responses on the part of the recipient animals.After the second grafts were in place for 3 weeks, the serum and lymphocytes of the animal grafted with allogeneic cancellous bone and marrow showed a higher degree of cytotoxicity for donor target cells than sera and cells from animals grafted with freeze‐dried material.The results indicate that there was little or no immune response, as detected by the assays used, to freeze‐dried cortical bone allografts in comparison to fresh cancellous bone and marrow allografts.