The use of 2 bioabsorbable barrier membranes in the treatment of interproximal intrabony periodontal defects

A collagen membrane containing osteogenic protein-1 facilitates bone regeneration in a rat mandibular bone defect

OBJECTIVES

Osteogenic protein-1 (OP-1) has shown osteoinductive activities and is useful for clinical treatments, including bone regeneration. Regenerative procedures using a bioabsorbable collagen membrane (BCM) are well established in periodontal and implant dentistry. We evaluated the subsequent effects of the BCM in combination with OP-1 on bone regeneration in a rat mandibular circular critical-sized bone defect in vivo.

DESIGN

We used 8 rats that received surgery in both sides of the mandible, and created the total 16 defects which were divided into 4 groups: Group 1; no treatment, as a control, Group 2; BCM alone, Group 3; BCM containing low dose 0.5μg of OP-1 (L-OP-1), and Group 4; BCM containing high dose 2.0μg of OP-1 (H-OP-1). Newly formed bone was evaluated by micro computed tomography (micro-CT) and histological analyses at 8 weeks postoperatively. In quantitative and qualitative micro-CT analyses of the volume of new bone formation, bone density, and percentage of new bone area was evaluated.

RESULTS

BCM with rhOP-1 significantly increased and accelerated bone volume, bone mineral density, and percentage of new bone area compared to control and BCM alone at 8 weeks after surgery; these enhancements in bone regeneration in the OP-1-treated groups were dose-dependent.

CONCLUSIONS

OP-1 delivered with a BCM may have effective osteoinductive potency and be a good combination for bone regeneration. The use of such a combination device for osteogenesis may result in safer and more predictable bone regenerative outcomes in the future.

Poly(Lactic-co-Glycolic Acid): Applications and Future Prospects for Periodontal Tissue Regeneration

Periodontal tissue regeneration is the ultimate goal of the treatment for periodontitis-affected teeth. The success of regenerative modalities relies heavily on the utilization of appropriate biomaterials with specific properties. Poly (lactic-co-glycolic acid) (PLGA), a synthetic aliphatic polyester, has been actively investigated for periodontal therapy due to its favorable mechanical properties, tunable degradation rates, and high biocompatibility. Despite the attractive characteristics, certain constraints associated with PLGA, in terms of its hydrophobicity and limited bioactivity, have led to the introduction of modification strategies that aimed to improve the biological performance of the polymer. Here, we summarize the features of the polymer and update views on progress of its applications as barrier membranes, bone grafts, and drug delivery carriers, which indicate that PLGA can be a good candidate material in the field of periodontal regenerative medicine.

Synthesis and characterization of a POSS-PEG macromonomer and POSS-PEG-PLA hydrogels for periodontal applications

A novel water-soluble macromonomer based on octavinyl silsesquioxane has been synthesized and contains vinyl-terminated PEG 400 in each of the eight arms to promote water solubility. The macromonomer was characterized by NMR and FTIR and its aqueous solution properties examined. In water it exhibits an LCST with a cloud point at 23 °C for a 10 wt % aqueous solution. It is surface active with a CMC of 1.5 × 10(-5) M in water and in 20:80 v/v acetone/water the CMC is 7.1 × 10(-5) M, and TEM images showed spherical 22 nm aggregates in aqueous solution above the CMC. The macromonomer was copolymerized in a 20:80 v/v acetone/water mixture with a vinyl-terminated, triblock copolymer of lactide-PEG-lactide to form a library of cross-linked hydrogels that were designed for use as scaffolds for alveolar bone repair. The cross-linked copolymer networks were shown to contain a range of nm-μm sized pores and their swelling properties in water and PBS at pH 7.4 were examined. At pH 7.4 the hydrogel networks undergo a slow hydrolysis with the release of principally PEG and lactic acid fragments. The hydrogels were shown to be noncytotoxic toward fibroblast cultures at pH 7.4, both initially (days 1-5) and after significant hydrolysis had taken place (days 23-28).

Comparison of treatment effects of guided tissue regeneration on infrabony lesions between animal and human studies: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

For ethical reasons it is becoming increasingly more difficult to obtain, from clinical studies, histological data on infrabony defects treated with guided tissue regeneration (GTR) techniques. The aim of this systematic review was to find the value of extrapolating animal data on treatment of periodontal infrabony lesions, using GTR only or GTR + bone grafts, to human clinical results.

MATERIAL AND METHODS

Searches of the PubMed and Cochrane databases were combined with hand searching of articles published from 1 January 1969 to 1 August 2012. The search included any type of barrier membrane, with or without grafted materials, used to treat periodontal infrabony lesions. All studies with histological or re-entry methodology outcome parameters that evaluated bone-filling and/or new-cementum-formation ratios from a defect depth were collected. When comparing animal and human outcomes, a meta-analysis was used to evaluate the bone-filling ratio, but only a descriptive analysis of the histological studies was performed.

RESULTS

In total, 22 studies were selected for the meta-analysis. In the GTR + bone graft groups the weighted-average bone-filling ratios were 52% (95% CI: 18-85%) in animals and 57% (95% CI: 30-83%) in humans, which were not statistically significantly different (p = 0.825). Similar results were found in the GTR-only groups, in which the weighted-average bone-filling ratios were 54% (95% CI: 37-72%) in animals and 59% (95% CI: 42-77%) in humans (p = 0.703). New-cementum formation of GTR only and GTR + bone grafts showed comparable ratio outcomes, and both were superior to the control group in animals only (p = 0.042).

CONCLUSION

Although quality assessments differed between animal and human studies, our analysis indicated that animal models and human results showed similar bone-filling ratios in infrabony defects treated with GTR only or with GTR + bone grafting.

Evaluation of relative efficacy of β-tricalcium phosphate with and without type I resorbable collagen membrane in periodontal infrabony defects: a clinical and radiographic study

BACKGROUND AND OBJECTIVES

To compare clinically and radiographically, the regenerative potential of a β-tricalcium phosphate bone graft, Cerasorb(®) with and without a bioresorbable type I collagen membrane, BioMend Extend™, in treating periodontal infrabony osseous defects.

MATERIALS AND METHODS

A total of 20 sites from 10 patients showing bilateral infrabony defects were selected and selected sites were randomly divided into experimental site A (Cerasorb(®)) and experimental site B (Cerasorb(®) and BioMend Extend™) by using split mouth design. The clinical parameters like plaque index, gingival index, probing pocket depth, clinical attachment level and gingival recession were recorded at baseline, 6 weeks, 3, 6 and 9 months. Radiographic evaluation (Linear CADIA) at 6 and 9 months; and intrasurgical measurements at baseline and 9 months were carried out to evaluate the defect fill, change in alveolar crest height and defect resolution.

RESULTS

Significant reduction in all clinical parameters was observed in both the groups. On comparison no statistical significance was observed between the two groups. Radiographically, in site A there was significant defect fill of 78.4 and 97.2% at 6 and 9 months respectively. Whereas in site B reduction was 78.4 and 97.2% at 6 and 9 months respectively. After surgical re-entry, there was significant defect fill of 89.2 and 74% in both groups.

INTERPRETATION AND CONCLUSION

Individually both the graft and membrane have shown promising results in the management of periodontal intrabony defects. But the added benefit by combining Cerasorb(®) with BioMend Extend™ was not observed statistically in both clinical radiographic findings.

Position Paper: Periodontal Regeneration

Untreated periodontal disease leads to tooth loss through destruction of the attachment apparatus and tooth-supporting structures. The goals of periodontal therapy include not only the arrest of periodontal disease progression,but also the regeneration of structures lost to disease where appropriate. Conventional surgical approaches (e.g., flap debridement) continue to offer time-tested and reliable methods to access root surfaces,reduce periodontal pockets, and attain improved periodontal form/architecture. However, these techniques offer only limited potential towards recovering tissues destroyed during earlier disease phases. Recently, surgical procedures aimed at greater and more predictable regeneration of periodontal tissues and functional attachment close to their original level have been developed, analyzed, and employed in clinical practice. This paper provides a review of the current understanding of the mechanisms, cells, and factors required for regeneration of the periodontium and of procedures used to restore periodontal tissues around natural teeth. Targeted audiences for this paper are periodontists and/or researchers with an interest in improving the predictability of regenerative procedures. This paper replaces the version published in 1993.

Polylactide-polyglycolide antibiotic implants

Surgeons continually struggle to reduce orthopaedic infections, but no current treatment offers minimum side effects with maximum effectiveness. Antibiotics mixed in plaster of paris have been successful in treating large bony defects in patients with chronic osteomyelitis, and have the advantage of being well tolerated and absorbed by the body. Antibiotics impregnated in polymethylmethacrylate (PMMA) have offered local antibiotic delivery with some success. However, the effect of the antibiotic on the bone cement, the inconsistent elution of the antibiotic, and the need to remove the PMMA implant drives the need for a better system of antibiotic delivery. Polymers or copolymers of antibiotic-impregnated polylactic acid, polyglycolic acid or polyparadioxanone may provide an absorbable system for localized antibiotic delivery. Similar biodegradable systems used to treat small bone fractures have been successful with minimal side effects. In vitro studies have shown promising results of antibiotic elution from bioabsorbable microspheres and beads. Animal in vivo tests have shown that antibiotic impregnated polymers can successfully treat induced osteomyelitis in rabbits and dogs. These studies have provided consistent reproducible results, and now it is time to plan human trials to assess the efficacy of antibiotic microspheres implanted in infected bone and to plan in vivo and in vitro animal testing to investigate the feasibility of antibiotic-polymer-coated components.

Periodontal regeneration techniques for treatment of periodontal diseases

The ultimate goal of periodontal therapy is the regeneration of structures lost to disease. Conventional surgical approaches such as open-flap debridement offer only limited regeneration potential.Currently, surgical procedures for predictable regeneration of periodontal tissues are being developed, analyzed, and employed in clinical practice. This article addresses current trends in periodontal regeneration. Various materials/agents such as bone replacement grafts, barrier membranes, and biologic modifiers currently used for the regeneration of periodontal infrabony and furcation defects are discussed.

Biodegradation of differently cross-linked collagen membranes: an experimental study in the rat

The aim of the present study was to compare the biodegradation of differently cross-linked collagen membranes in rats. Five commercially available and three experimental membranes (VN) were included: (1) BioGide (BG) (non-cross-linked porcine type I and III collagens), (2) BioMend (BM), (3) BioMendExtend (BME) (glutaraldehyde cross-linked bovine type I collagen), (4) Ossix (OS) (enzymatic-cross-linked bovine type I collagen), (5) TutoDent (TD) (non-cross-linked bovine type I collagen, and (6-8) VN(1-3) (chemical cross-linked porcine type I and III collagens). Specimens were randomly allocated in unconnected subcutaneous pouches separated surgically on the back of 40 wistar rats, which were divided into five groups (2, 4, 8, 16, and 24 weeks), including eight animals each. After 2, 4, 8, 16, and 24 weeks of healing, the rats were sacrificed and explanted specimens were prepared for histologic and histometric analysis. The following parameters were evaluated: biodegradation over time, vascularization, tissue integration, and foreign body reaction. Highest vascularization and tissue integration was noted for BG followed by BM, BME, and VN(1); TD, VN(2), and VN(3) showed prolongated, while OS exhibited no vascularization. Subsequently, biodegradation of BG, BM, BME and VN(1) was faster than TD, VN(2), and VN(3). OS showed only a minute amount of superficial biodegradation 24 weeks following implantation. Biodegradation of TD, BM, BME, VN(2), and VN(3) was associated with the presence of inflammatory cells. Within the limits of the present study, it was concluded that cross-linking of bovine and porcine-derived collagen types I and III was associated with (i) prolonged biodegradation, (ii) decreased tissue integration and vascularization, and (iii) in case of TD, BM, BME, VN(2), and VN(3) foreign body reactions.

Guided tissue regeneration in intrabony periodontal defects following treatment with two bioabsorbable membranes in combination with bovine bone mineral graft. A clinical and radiographic study

AIM

Comparison of two bioabsorbable barriers (collagen and polylactic acid (PLA) membranes) combined with a bovine bone mineral (BBM) graft, with an access flap procedure (AFP) alone for treating intrabony defects.

MATERIAL AND METHODS

Thirty-four subjects participated in this prospective, controlled clinical trial. Baseline clinical examination (probing depth (PD), clinical attachment level (CAL)) of selected sites was performed 2 months after completion of conservative treatment in conjunction with hard-tissue measurements to ascertain the depth of the defect (cementoenamel junction to the bottom of the defects). After randomly dividing patients into three groups (two membrane groups, one control group), full thickness flaps were elevated and exposed root surfaces planed before filling defects with bone graft and positioning a barrier membrane covering the defect. The control group was treated identically except for the barrier and bone graft placement. Clinical treatment outcomes were finally evaluated 12 months after surgery for changes of PD and CAL. Radiographs at baseline and 12 months were compared using non-standardized digital radiography.

RESULTS

A mean reduction in PD value of 5.08 mm and mean CAL gain of 4.39 mm occurred in the collagen-BBM group. Corresponding values for the PLA-BBM group were 4.72 and 3.71 mm, while access flap procedure (AFP) sites produced values of 2.50 and 2.43 mm. All improvements in clinical parameters were statistically significant (p<0.001) within groups for all variables. Both membranes produced statistically greater PD reduction and CAL gain compared with AFP treatment (p<0.05). Comparison between barrier groups failed to reveal any statistically significant difference in probing pocket depth reduction (p=0.56) or in CAL gain (p=0.34).

CONCLUSION

Placement of the two barrier membranes used in the present study in combination with BBM graft significantly improved clinical and radiographic parameters of deep intrabony pockets and proved superior to access flap alone.

GTR treatment of intrabony defects with PLA/PGA copolymer or collagen bioresorbable membranes in combination with deproteinized bovine bone (Bio-Oss)

The objectives of this study were to evaluate the results of guided tissue regeneration (GTR) treatment of intrabony defects with two kinds of bioresorbable membranes, with deproteinized bovine bone (Bio-Oss) used as an adjunct. Twenty-eight patients with at least one intrabony defect with a probing pocket depth (PPD) >/=7 mm and radiographic evidence of an intrabony component (IC) >/=4 mm were randomly treated with either a polylactic/polyglycolic (PLA/PGA) acid copolymer or a collagen bioresorbable membrane combined with Bio-Oss implantation. Immediately prior to surgery (baseline) and after 1 year, the following parameters were recorded: (1) PPD, (2) gingival recession (REC), (3) probing attachment level (PAL), (4) presence/absence of plaque (PI), and (5) presence/absence of bleeding on probing (BOP). Occurrence of membrane exposure during healing and the smoking habits of the patients were also recorded. Statistical analysis was carried out using chi(2) -tests and t-tests. There were no significant differences between the two membrane groups regarding the clinical parameters at baseline. Statistically significant clinical improvements (PAL gains, reduced PPDs) were observed 1 year after treatment in both groups. There were no significant differences, however, between the PLA/PGA and the collagen membrane groups regarding any of the evaluated parameters (mean PAL gain: 2.9 mm vs 3.9 mm; mean residual PPD: 4.8 mm vs 4.1 mm, respectively). The membrane material per se does not seem to be a critical factor for the outcome of GTR treatment of intrabony defects with bioresorbable membranes.

Effect of sustained gene delivery of platelet-derived growth factor or its antagonist (PDGF-1308) on tissue-engineered cementum

BACKGROUND

Cementum, a mineralized tissue lining the tooth root surface, is destroyed during the inflammatory process of periodontitis. Restoration of functional cementum is considered a criterion for successful regeneration of periodontal tissues, including formation of periodontal ligament, cementum, and alveolar bone. Short-term administration of platelet-derived growth factor (PDGF) has been shown to partially regenerate periodontal structures. Nonetheless, the role of PDGF in cementogenesis is not well understood. The aim of the present study was to determine the effect of sustained PDGF gene transfer on cementum formation in an ex vivo ectopic biomineralization model.

METHODS

Osteocalcin (OC) promoter-driven SV40 transgenic mice were used to obtain immortalized cementoblasts (OCCM). The OCCM cells were transduced with adenoviruses (Ad) encoding either PDGF-A, an antagonist of PDGF signaling (PDGF-1308), a control virus (green fluorescent protein, GFP), or no treatment (NT). The transduced cells were incorporated into polymer scaffolds and implanted subcutaneously into severe combined immunodeficient (SCID) mice. The implants were harvested at 3 and 6 weeks for histomorphometric analysis of the newly formed mineralized tissues. Northern blot analysis was performed to determine the expression levels of mineral-associated genes including bone sialoprotein (BSP), OC, and osteopontin (OPN) in the cell-implant specimens at 3 and 6 weeks.

RESULTS

The results indicated mineralization was significantly reduced in both the Ad/PDGF-A and Ad/PDGF-1308 treated specimens when compared to the NT or Ad/GFP groups at 3 and 6 weeks (P<0.01). In addition, the size of the implants treated with Ad/PDGF-A and Ad/PDGF-1308 was significantly reduced compared to implants from Ad/GFP and NT groups at 3 weeks (P<0.05). At 6 weeks, the size of implants and mineral formation increased in NT, Ad/GFP, and Ad/PDGF-A groups, while the Ad/PDGF-1308 treated implants continued to decrease in size and mineral formation (P<0.01). Northern blot analysis revealed that in the Ad/PDGF-A treated implants OPN was increased, whereas OC gene expression was downregulated at 3 weeks. In the Ad/PDGF-1308 treated implants, BSP, OC, and OPN were all downregulated at 3 weeks. At 3 weeks, the Ad/PDGF-A treated implants contained significantly higher multinucleated giant cell (MNGC) density compared to NT, Ad/GFP, and Ad/PDGF-1308 specimens. The MNGC density in NT, Ad/GFP, and Ad/PDGF-A treated groups reduced over time, while the Ad/PDGF-1308 transduced implants continued to exhibit significantly higher MNGC density compared with the other treatment groups at 6 weeks.

CONCLUSIONS

The results showed that continuous exposure to PDGF-A had an inhibitory effect on cementogenesis, possibly via the upregulation of OPN and subsequent enhancement of MNGCs at 3 weeks. On the other hand, Ad/PDGF-1308 inhibited mineralization of tissue-engineered cementum possibly due to the observed downregulation of BSP and OC and a persistence of stimulation of MNGCs. These findings suggest that continuous exogenous delivery of PDGF-A may delay mineral formation induced by cementoblasts, while PDGF is clearly required for mineral neogenesis.

Cementum engineering with three-dimensional polymer scaffolds

Cloned cementoblasts (OCCMs), periodontal ligament fibroblasts (SV-PDLs), and dental follicle (SV-F) cells obtained from mice were used as a tool to study periodontal tissue engineering. OCCM, SV-PDL, and SV-F cells were seeded onto three-dimensional poly lactic-co-glycolic acid (PLGA) scaffolds and cultured with the use of bioreactors or implanted subcutaneously in severe combined immune deficiency (SCID) mice for up to 6 weeks. We explored the behavior of these cells in porous PLGA sponges by cell growth, expression of mineral-associated genes using reverse transcriptase polymerase chain reaction, and mineralization by histologic analysis in vitro and in vivo. Results indicated that cells attached to PLGA scaffolds under either static or dynamic conditions in vitro. Only OCCM implants, retrieved from both in vitro bioreactors and SCID mice at 3-and 6-weeks post-cell implantation exhibited mineral formation. Types I and XII collagens, osteocalcin, and bone sialoprotein genes were detected in all implants retrieved from SCID mice. These results suggest that delivery of selected cells via PLGA scaffolds may serve as a viable approach for promoting periodontal tissue regeneration.

Comparison of Porous and Non-Porous Teflon Membranes Plus a Xenograft in the Treatment of Vertical Osseous Defects: A Clinical Reentry Study

BACKGROUND

The primary aim of this 9-month randomized, controlled, blinded, clinical reentry study was to compare the regenerative effects of a nonporous polytetrafluoroethylene (NP) periodontal membrane to a porous expanded polytetrafluoroethylene (P) periodontal membrane in the treatment of vertical osseous defects.

METHODS

Twenty-four patients, 11 males and 13 females, age 24 to 74 (mean 50.5 +/- 13.1) provided one site with an intraosseous defect > or = 4 mm and were divided equally and randomly into two groups. Following debridement both groups were grafted with a bovine-derived xenograft coated with a synthetic cell-binding peptide; then the test group received an NP membrane and the control group received a P membrane. All defects were reentered after 9 months. Measurements were performed by a masked examiner.

RESULTS

There were no statistically significant differences (P>0.05) between NP and P groups for any open or closed probing measurement at any time. Similar open initial defect depth for the NP group and P groups (4.8 versus 5.0 mm) demonstrated identical 9-month defect fill of 2.8 mm (57%) for both groups. A difference in crestal resorption for the NP compared to the P group (0.4 versus 0.8 mm) accounted for the difference in mean percent defect resolution, which was 67% for NP compared to 72% for the P group. Overall, nine (75%) of the NP group defects and eight (67%) of the P group defects showed more than 50% defect fill.

CONCLUSION

Treatment of vertical osseous defects with nonporous or porous polytetrafluoroethylene membranes in combination with a xenograft resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups.

Bioabsorbable membrane and bioactive glass in the treatment of intrabony defects in patients with generalized aggressive periodontitis: results of a 12-month clinical and radiological study

BACKGROUND

Guided tissue regeneration can be achieved using membranes. In recent years, some evidence has been provided that bioactive glass is also capable of supporting the regenerative healing of periodontal lesions. The aim of this clinical and radiological prospective study was to compare the effectiveness of a bioabsorbable membrane and a bioactive glass in the treatment of intrabony defects in patients with generalized aggressive periodontitis.

METHODS

Twelve patients (9 females, 3 males) with generalized aggressive periodontitis were enrolled in the study. The investigations were confined to 1- to 3-walled intrabony defects with a depth > or = 4 mm and with preoperative probing depths > or = 7 mm. Teeth with furcation involvement were excluded. Fifteen of the total 30 defects were treated with the membrane (RXT group) and 15 with the bioactive glass (PG group). Allocation to the groups was randomized. The clinical parameters plaque index (PI), gingival index (GI), probing depth (PD), bleeding on probing (BOP), gingival recession (GR), clinical attachment level (CAL), and mobility were recorded prior to surgery as well as 6 and 12 months after surgery. Intraoral radiographs were taken in standardized paralleling technique at baseline and 12 months after the surgery. Following digitization, changes in the distances from the alveolar crest (xCA) to the defect base (xBD) and from the CEJ (xCEJ) to the xCA were determined. Statistical analysis was based on Kolmogorov-Smirnov test, Wilcoxon signed-ranks test, analysis of covariance, and Spearman's bivariate correlation analysis.

RESULTS

After 12 months, a reduction in PD of 4.0 +/- 2.1 mm (P < 0.001) and a gain in CAL of 3.4 +/- 2.3 mm (P < 0.001) was registered in the RXT group. There was a slight increase in GR by 0.6 +/- 1.5 mm (P = 0.074). In the PG group, a reduction in PD of 3.8 +/- 1.9 mm (P < 0.001) and a gain in CAL of 2.8 +/- 1.9 mm (P < 0.001) was recorded, whereas GR increased by 1.0 +/- 1.4 mm (P = 0.007). The 6-month results did not differ significantly from the stated values. Radiographically, the defects (xCA to xBD) were found to be filled by 57.2 +/- 33.5% (P = 0.001) in the RXT group and by 50.5 +/- 22.8% (P = 0.001) in the PG group. Crestal resorption (xCEJ to xCA) was 6.1 +/- 34.5% (P = 0.910) in the RXT group and 15.1 +/- 39.7% (P = 0.433) in the PG group. Only the change in gingival recession after 12 months was significantly greater (P = 0.031) in the PG group, with -1.0 +/- 1.4 mm, compared to the RXT group, with -0.6 +/- 1.5 mm. Changes in the other clinical and radiological parameters showed no significant differences. The attachment gain correlated negatively with the preoperative PI (r = -0.574; P = 0.004) and with BOP after 6 months (r = -0.315; P = 0.021).

CONCLUSIONS

Highly significant improvements in the parameters PD, CAL, and xCA-xBD were recorded after 6 and 12 months, respectively, with both regenerative materials. A good standard of oral hygiene and inflammation-free periodontal tissue in the postoperative phase improved the treatment outcome.

Collagen membranes: a review

Collagen materials have been utilized in medicine and dentistry because of their proven biocompatability and capability of promoting wound healing. For guided tissue regeneration (GTR) procedures, collagen membranes have been shown to be comparable to non-absorbable membranes with regard to probing depth reduction, clinical attachment gain, and percent of bone fill. Although these membranes are absorbable, collagen membranes have been demonstrated to prevent epithelial down-growth along the root surfaces during the early phase of wound healing. The use of grafting material in combination with collagen membranes seems to improve clinical outcomes for furcation, but not intrabony, defects when compared to the use of membranes alone. Recently, collagen materials have also been applied in guided bone regeneration (GBR) and root coverage procedures with comparable success rates to non-absorbable expanded polytetrafluoroethylene (ePTFE) membranes and conventional subepithelial connective tissue grafts, respectively. Long-term clinical trials are still needed to further evaluate the benefits of collagen membranes in periodontal and peri-implant defects. This article will review the rationale for each indication and its related literature, both in vitro and in vivo studies. The properties that make collagen membranes attractive for use in regenerative therapy will be addressed. In addition, varieties of cross-linking techniques utilized to retard the degradation rate of collagen membranes will be discussed.

New clinical materials and techniques in guided tissue regeneration

AIM

To review the evidence on using Guided Tissue Regeneration (GTR) techniques and materials in various clinical circumstances.

METHOD

Literature review.

MAIN OUTCOME MEASURES

The success of GTR techniques and materials in halting or reversing the destruction of tooth attachment apparatus caused by progressive periodontal disease.

RESULTS

GTR and osseous grafting are the two techniques with the most clinical and histological documentation of periodontal regeneration.

CONCLUSIONS

GTR materials, whether non-resorbable or bioabsorbable, give similar clinical results. GTR procedures have been demonstrated to be clinically effective in treating infrabony osseous defects, recession defects, preserving alveolar bone in recent extraction sites and in some types of furcation defects. GTR procedures are technique sensitive and are adversely affected by poor home oral hygiene care, poor follow-up professional maintenance care and smoking.