A clinical comparison of collagen membranes with e-PTFE membranes in the treatment of human mandibular buccal class II furcation defects

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.

Effect of Different Membranes on Vertical Bone Regeneration: A Systematic Review and Network Meta-Analysis

This study is aimed at performing a systematic review and a network meta-analysis of the effects of several membranes on vertical bone regeneration and clinical complications in guided bone regeneration (GBR) or guided tissue regeneration (GTR). We compared the effects of the following membranes: high-density polytetrafluoroethylene (d-PTFE), expanded polytetrafluoroethylene (e-PTFE), crosslinked collagen membrane (CCM), noncrosslinked collagen membrane (CM), titanium mesh (TM), titanium mesh plus noncrosslinked (TM + CM), titanium mesh plus crosslinked (TM + CCM), titanium-reinforced d-PTFE, titanium-reinforced e-PTFE, polylactic acid (PLA), polyethylene glycol (PEG), and polylactic acid 910 (PLA910). Using the PICOS principles to help determine inclusion criteria, articles are collected using PubMed, Web of Science, and other databases. Assess the risk of deviation and the quality of evidence using the Cochrane Evaluation Manual, and GRADE. 27 articles were finally included. 19 articles were included in a network meta-analysis with vertical bone increment as an outcome measure. The network meta-analysis includes network diagrams, paired-comparison forest diagrams, funnel diagrams, surface under the cumulative ranking curve (SUCRA) diagrams, and sensitivity analysis diagrams. SUCRA indicated that titanium-reinforced d-PTFE exhibited the highest vertical bone increment effect. Meanwhile, we analyzed the complications of 19 studies and found that soft tissue injury and membrane exposure were the most common complications.

Treating short upper lip with "Unified lip repositioning" technique: Two case reports

Excessive gingival display can be an esthetic concern for the patient. Conventional lip repositioning provides a conservative surgical option with less patient morbidity. The unified technique is a modification of conventional lip repositioning technique using the orthodontic brackets as anchorage to provide better soft-tissue closure with the lesser chances of relapse. This technique has been modified to be less invasive with better results. In this case report, patients undergoing orthodontic treatment with short upper lip were recommended for the surgical lip repositioning to reduce excess gingival display. Cases were treated with conventional lip repositioning technique and with unified lip repositioning technique, and after evaluation, comparison was done postoperatively. The unified lip repositioning technique showed better results with a significant decrease of gingival appearance and more patient compliance. Thus, in patients with short upper lip, unified lip repositioning technique can be a viable conservative treatment option.

Regenerative surgical treatment of furcation defects: A systematic review and Bayesian network meta-analysis of randomized clinical trials

AIMS

To investigate the clinical performance of regenerative periodontal surgery in the treatment of furcation defects versus open flap debridement (OFD) and to compare different regenerative modalities.

MATERIAL AND METHODS

A systematic search was conducted to identify RCTs evaluating regenerative surgical treatment of furcations with a minimum of 12-month follow-up. Three authors independently reviewed, selected and extracted data from the search conducted and assessed risk of bias. Primary outcomes were tooth loss, furcation improvement (closure/conversion) (FImp), gain of horizontal bone level (HBL) and attachment level (HCAL). Secondary outcomes were gain in vertical attachment level (VCAL), probing pocket depth (PPD) reduction, PROMs and adverse events. Data were summarized into Bayesian standard and network meta-analysis in order to estimate direct and indirect treatment effects and to establish a ranking of treatments.

RESULTS

The search identified 19 articles, reporting on 20 RCTs (19 on class II, 1 on class III furcations) with a total of 575 patients/787 defects. Tooth loss was not reported. Furcation closure ranged between 0% and 60% (10 trials), and class I conversion from 29% to 100% (six trials). Regenerative techniques were superior to OFD for FImp (OR = 20.9; 90% CrI = 5.81, 69.41), HCAL gain (1.6 mm), VCAL gain (1.3 mm) and PPD reduction (1.3 mm). Bone replacement grafts (BRG) resulted in the highest probability (Pr = 61%) of being the best treatment for HBL gain. Non-resorbable membranes + BRG ranked as the best treatment for VCAL gain (Pr = 75%) and PPD reduction (Pr = 56%).

CONCLUSIONS

Regenerative surgery of class II furcations is superior to OFD. FImp (furcation closure or class I conversion) can be expected for the majority of defects. Treatment modalities involving BRG are associated with higher performance.

Compression-Resistant Polymer/Ceramic Composite Scaffolds Augmented with rhBMP-2 Promote New Bone Formation in a Nonhuman Primate Mandibular Ridge Augmentation Model

PURPOSE

This study was designed to test the hypothesis that compression-resistant (CR) scaffolds augmented with recombinant human bone morphogenetic protein-2 (rhBMP-2) at clinically relevant doses in a nonhuman primate lateral ridge augmentation model enhances bone formation in a dose-responsive manner without additional protective membranes.

MATERIALS AND METHODS

Defects (15 mm long × 8 mm wide × 5 mm deep) were created bilaterally in the mandibles of nine hamadryas baboons. The defect sites were implanted with poly(ester urethane) (PEUR)/ceramic CR scaffolds augmented with 0 mg/mL rhBMP-2 (CR control), 0.75 mg/mL rhBMP-2 (CR-L), or 1.5 mg/mL rhBMP-2 (CR-H). The primary outcome of ridge width and secondary outcomes of new bone formation, cellular infiltration, and integration with host bone were evaluated using histology, histomorphometry, and microcomputed tomography (micro-CT) at 16 weeks following implantation.

RESULTS

New bone formation in the mandible was observed in a dose-responsive manner. CR-H promoted significantly greater new bone formation compared with the CR control group. In all groups, ridge width was maintained without an additional protective membrane.

CONCLUSION

CR scaffolds augmented with a clinically relevant dose of rhBMP-2 (1.5 mg/mL) promoted significant new bone formation. These results suggest that a CR PEUR/ceramic composite scaffold without a protective membrane may be a potential new rhBMP-2 carrier for clinical use.

The application of "bone window technique" using piezoelectric saws and a CAD/CAM-guided surgical stent in endodontic microsurgery on a mandibular molar case

Apical surgery for a mandibular molar is still challenging for many reasons. This report describes the applications of computer-guided cortical ‘bone-window technique’ using piezoelectric saws that prevented any nerve damage in performing endodontic microsurgery of a mandibular molar. A 49-year-old woman presented with gumboil on tooth #36 (previously endodontically treated tooth) and was diagnosed with chronic apical abscess. Periapical lesions were confirmed using cone-beam computed tomography (CBCT). Endodontic microsurgery for the mesial and distal roots of tooth #36 was planned. Following the transfer of data of the CBCT images and the scanned cast to an implant surgical planning program, data from both devices were merged. A surgical stent was designed, on the superimposed three-dimensional model, to guide the preparation of a cortical window on the buccal side of tooth #36. Endodontic microsurgery was performed with a printed surgical template. Minimal osteotomy was required and preservation of the buccal cortical plate rendered this endodontic surgery less traumatic. No postoperative complications such as mental nerve damage were reported. Window technique guided by a computer-aided design/computer-aided manufacture based surgical template can be considerably useful in endodontic microsurgery in complicated cases.

New Perspectives in the Use of Biomaterials for Periodontal Regeneration

Periodontitis is a disease with a high prevalence among adults. If not treated, it can lead to loss of teeth. Periodontal therapy aims at maintaining patient’s teeth through infection control and correction of non-maintainable anatomies including—when possible—regeneration of lost periodontal tissues. The biological regenerative potential of the periodontium is high, and several biomaterials can be utilized to improve the outcome of periodontal therapy. Use of different natural and synthetic materials in the periodontal field has been studied for many years. The main materials used today in periodontology analyzed in this review are: Resorbable and non-resorbable barrier membranes; autogenous, allogeneic, xenogeneic, and alloplastic bone substitutes; biological agents, such as amelogenins; platelet-derived growth factor; bone morphogenic proteins; rh fibroblast growth factor 2; teriparatide hormone; platelet concentrates; and 3D scaffolds. With the development of new surgical techniques some concepts on periodontal regeneration that were strictly applied in the past seem to be not so critical today. This can have an impact on the materials that are needed when attempting to regenerate lost periodontal structures. This review aims at presenting a rationale behind the use of biomaterials in modern periodontal regeneration

Comparison of Attachment and Proliferation of Human Gingival Fibroblasts on Different Collagen Membranes

Background and Aim

Human gingival fibroblasts cultured on collagen membrane as an alternative treatment method used in tissue regeneration can lead to improved results in root coverage. The aim of this study was to evaluate the human gingival fibroblast proliferation and adhesion cultured on three types of collagen membranes.

Materials and Methods

In this in vitro study, first-line human gingival fibroblast cells (HGF1-RT1) prepared and cultured on three membranes, including porcine pericardium (PP) (Jason, Botiss dental), human pericardium (HP) (Regen, Faravardeh Baft Iranian), and glutaraldehyde cross-linked (GC) (BioMend Extend, Zimmer Dental). Cell survival was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) after 24, 48, and 72 h and 7 days. Furthermore, morphology and adhesion of cells on the membrane were evaluated after 1 and 7 days by electron microscopy (scanning electron microscopy [SEM]). Statistical analysis was performed using two-way ANOVA with a significance level of 0.05.

Results

Based on the results of MTT, cell survival on HP and PP membranes after 7 days significantly increased (P < 0.001), but for the GC membrane, it was reduced after 7 days (P = 0.031). Cell survival on HP and PP membranes did not differ (P = 1) and was more than GC (P < 0.001). SEM images showed that the adhesion of cells was better on HP and PP membranes than GC.

Conclusion

The results of this study showed that natural collagen membranes (HP and PP) similarly support proliferation and adhesion of gingival fibroblasts. Survival and adhesion of gingival fibroblasts on cross-linked collagen membrane was less than two other membranes.

Comparative study of nonabsorbable and absorbable barrier membranes in periodontal osseous defects by guided tissue regeneration

BACKGROUND

Periodontal invasion of furcation area in multirooted teeth represents one of the most demanding therapeutic challenges in periodontics. Furcation therapy includes various treatment modalities like either maintenance or elimination of furcation or increased access to furcation area. Recent treatment modalities include regenerative procedures like placement of different type of bone grafts with nonabsorbable or absorbable barrier membranes, through guided tissue regeneration. This study compared the clinical efficacy of nonabsorbable barrier membrane with absorbable membrane when used with hydroxyapatite bone graft (G-Graft) in grade II buccal furcation defects in mandibular 1st molars.

MATERIALS AND METHODS

Fourteen subjects with bilateral grade II buccal furcation defects in lower 1st molars were selected and treated in a split-mouth design. After phase I therapy, molars were divided randomly into two groups for the treatment with either resorbable or nonresorbable membrane in conjunction with G-Graft in both groups.

RESULTS

All the clinical parameters recorded showed statistically significant improvement in both the groups but no significant difference between two groups was observed.

CONCLUSION

Both nonabsorbable and absorbable barrier membranes were equally effective in treating grade II buccal furcation defects in lower molars when used in conjunction with G-Graft except with respect to horizontal bone fill in which absorbable barrier membrane showed better results.

Periodontal regeneration - furcation defects: a systematic review from the AAP Regeneration Workshop

BACKGROUND

The aim of this review is to present the available evidence regarding the effectiveness of different regenerative approaches for the treatment of furcation defects in specific clinical scenarios compared with conventional surgical therapy to provide clinical guidelines for the therapeutic management of furcation defects and to identify priorities for future research that may advance the understanding of periodontal regenerative medicine.

METHODS

A comprehensive search based on predetermined eligibility criteria was conducted to identify human original studies and systematic reviews on the topic of periodontal regeneration of furcation defects. Two reviewers independently screened the title and abstract of the entries yielded from the initial search. Subsequently, both reviewers read the full-text version of potentially eligible studies, made a final article selection, and extracted the data of the selected studies considering specific clinical scenarios. The clinical scenarios contemplated in this review included the following: 1) facial and interproximal Class I defects in maxillary molars; 2) facial and lingual Class I defects in mandibular molars; 3) facial and interproximal Class II furcation defects in maxillary molars; 4) facial and lingual Class II furcation defects in mandibular molars; 5) Class III furcation defects in maxillary molars; 6) Class III furcation defects in mandibular molars; and 7) Class I, II, or III furcation defects in maxillary premolars. Endpoints of interest included different clinical, radiographic, microbiologic, histologic, and patient-reported outcomes.

RESULTS

The initial search yielded a total of 1,500 entries. The final selection consisted of 150 articles, of which six were systematic reviews, 109 were clinical trials, 27 were case series, and eight were case reports. A summary of the main findings of previously published systematic reviews and the available evidence relative to the indication of regenerative approaches for the treatment of furcation defects compared with conventional surgical therapy are presented. Given the marked methodologic heterogeneity and the wide variety of materials and techniques applied in the selected clinical trials, the conduction of a meta-analysis was not viable.

CONCLUSIONS

On the basis of the reviewed evidence, the following conclusions can be drawn. 1) Periodontal regeneration has been demonstrated histologically and clinically for the treatment of maxillary facial or interproximal and mandibular facial or lingual Class II furcation defects. 2) Although periodontal regeneration has been demonstrated histologically for the treatment of mandibular Class III defects, the evidence is limited to one case report. 3) Evidence supporting regenerative therapy in maxillary Class III furcation defects in maxillary molars is limited to clinical case reports. 4) In Class I furcation defects, regenerative therapy may be beneficial in certain clinical scenarios, although most Class I furcation defects may be successfully treated with non-regenerative therapy. 5) Future research efforts should be primarily directed toward the conduction of clinical trials to test novel regenerative approaches that place emphasis primarily on patient-reported outcomes and also on histologic demonstration of periodontal regeneration. Investigators should also focus on understanding the influence that local, systemic, and technical factors may have on the outcomes of regenerative therapy in furcation defects.

Estrogen enhances the bone regeneration potential of periodontal ligament stem cells derived from osteoporotic rats and seeded on nano-hydroxyapatite/collagen/poly(L-lactide)

This study investigated the effects of estrogen on the bone regeneration potential of periodontal ligament stem cells (PDLSCs) derived from osteoporotic rats and seeded on a collagen-based composite scaffold [nano-hydroxyapatite/collagen/poly(L-lactide) (nHAC/PLA)]. For this purpose, 48 healthy 3‑month-old Sprague-Dawley female rats were divided into 2 groups as follows: the bilaterally ovariectomized (OVX) rats and sham‑operated rats. The PDLSCs were isolated at 3 months after surgery (by which time postmenopausal osteoporosis had developed). The effects of estrogen on the characteristics of these cells seeded in a culture plate and of the cells seeded on nHAC/PLA were then investigated. The PDLSC + nHAC/PLA constructs were implanted subcutaneously into the backs of severe combined immunodeficient (SCID) mice for 12 weeks in order to examine the role of estrogen in the bone formation ability of PDLSCs derived from osteoporotic rats. The results from methyl thiazolyl tetrazolium (MTT) assay revealed that the proliferation of the cells derived from the rats in the OVX group was significantly higher than that of the cells derived from the rats in the sham-operated group at the stage of logarithmic growth. The staining intensity of alkaline phosphatase (ALP) and the mineralization of the cells derived from the rats in the OVX group was significantly weaker than that of the cells from the rats in the sham-operated group. When the PDLSCs were seeded on nHAC/PLA, ALP activity, osteocalcin (OCN) secretion, mineral formation and the mRNA expression levels of ALP, OCN, estrogen receptor (ER)α and ERβ in the cells derived from the rats in the OVX group were markedly decreased. Treatment with 17β-estradiol (E2) significantly weakened the proliferative ability of the cells derived from the OVX group rats, and enhanced their osteogenic differentiation ability and the mRNA expression levels of ALP, OCN, ERα and ERβ. When the constructs were implanted into the backs of SCID mice for 12 weeks, the results of histological analysis indicated that the constructs derived from the OVX group rats had a few newly formed bones and osteoids; however, a great number of newly formed bones and osteoids were present in the ones from the sham-operated group and the OVX + E2 group rats. Our findings further indicate that estrogen deficiency impairs the osteogenic differentiation potential of PDLSCs, and that ER plays an important role in the bone regeneration ability of PDLSCs. Estrogen enhances the bone regeneration potential of PDLSCs derived from osteoporotic rats and seeded on nHAC/PLA. This study may provide insight into the clinical management of periodontal bone tissue repair in postmenopausal women with the use of estrogen-mediated PDLSCs seeded on nHAC/PLA.

Mechanisms of guided bone regeneration: a review

Post-extraction crestal bone resorption is common and unavoidable which can lead to significant ridge dimensional changes. To regenerate enough bone for successful implant placement, Guided Bone Regeneration (GBR) is often required. GBR is a surgical procedure that uses barrier membranes with or without particulate bone grafts or/and bone substitutes. There are two approaches of GBR in implant therapy: GBR at implant placement (simultaneous approach) and GBR before implant placement to increase the alveolar ridge or improve ridge morphology (staged approach). Angiogenesis and ample blood supply play a critical role in promoting bone regeneration.

Clinical and radiographic evaluation of Bio-Gen with biocollagen compared with Bio-Gen with connective tissue in the treatment of class II furcation defects: a randomized clinical trial

OBJECTIVE

Treatment of furcation defects are thought to be challenging. The purpose of this study was to evaluate the clinical and radiographic parameters of Bio-Gen with Biocollagen compared with Bio-Gen with connective tissue in the treatment of Class II furcation defects.

MATERIAL AND METHODS

In this clinical trial, 24 patients with Class II furcation defect on a buccal or lingual mandibular molar were recruited. After oral hygiene instruction, scaling and root planing and achievement of acceptable plaque control, the patients were randomly chosen to receive either connective tissue and Bio-Gen (case group) or Biocollagen and Bio-Gen (control group). The following parameters were recorded before the first and re-entry surgery (six months later): vertical clinical attachment level (VCAL), gingival index (GI), plaque index (PI), horizontal probing depth (HPD), vertical probing depth (VPD), gingival recession (GR), furcation vertical component (FVC), furcation to alveolar crest (FAC), fornix to base of defect (FBD), and furcation horizontal component (FHC) were calculated at the time of first surgery and during re-entry. A digital periapical radiograph was taken in parallel before first surgery and re-entry. The radiographs were then analyzed by digital subtraction. The differences with p value <0.05 were considered significant.

RESULTS

Only the mean changes of FAC, FHC, mean of FHC, FBD in re-entry revealed statistically significant differences between the two groups. HPD, VPD, FBD, FAC, and FHC showed statistically significant differences after 6 months in the case group. However, in the control group, statistically significant differences were found in GR and HPD. We did not observe any significant difference in radiographic changes among the two groups.

CONCLUSION

The results of this trial indicate that better clinical outcomes can be obtained with connective tissue grafts in combination with bone material compared with a resorbable barrier with bone material. The differences in radiographic changes between the two groups, however, were not statistically significant.

Role of collagen membrane in lateral onlay grafting with bovine hydroxyapatite incorporated with collagen matrix in dogs

Purpose

The objective of this study was to elucidate the role of collagen membranes (CMs) when used in conjunction with bovine hydroxyapatite particles incorporated with collagen matrix (BHC) for lateral onlay grafts in dogs.

Methods

The first, second, and third premolars in the right maxilla of mongrel dogs (n=5) were extracted. After 2 months of healing, two BHC blocks (4 mm×4 mm×5 mm) were placed on the buccal ridge, one with and one without the coverage by a CM. The animals were sacrificed after 8 weeks for histometric analysis.

Results

The collagen network of the membranes remained and served as a barrier. The quantity and quality of bone regeneration were all significantly greater in the membrane group than in the no-membrane group (P<0.05).

Conclusions

The use of barrier membranes in lateral onlay grafts leads to superior new bone formation and bone quality compared with bone graft alone.

Biocompatibility and cytotoxic evaluation of drug-loaded biodegradable guided tissue regeneration membranes

BACKGROUND

In periodontology, Guided Tissue Regeneration (GTR) is based on the concept of providing a space for entry of cells with regenerative potential into the wound environment to initiate the regeneration of structures lost due to periodontal disease. First generation GTR membranes were primarily non-absorbable membranes like expanded polytetrafluorethylene which required a second surgery for its removal. This led researchers to explore absorbable materials like collagen and synthetic biodegradable polymers to fabricate GTR membranes. In the present study, biodegradable Polylactic acid (PLA) is used to fabricate membranes with the potential to be used for GTR therapy.

MATERIALS AND METHODS

Biocompatibility of the PLA membranes were evaluated in a subcutaneous guinea pig model. Antimicrobial effect of the drug-loaded PLA membranes were assessed against a drug-resistant Staphylococcus aureus bacterial isolate. The cytocompatibility of the drug-loaded membranes were evaluated using HeLa cell lines.

RESULTS

The PLA membranes were shown to be biocompatible. The drug-loaded PLA membranes showed significant activity against the bacterial isolate. Among the drug-loaded membranes, tetracycline-loaded membrane showed minimal cellular toxicity.

CONCLUSION

The results of this study indicate that biodegradable drug-releasing polylactide membranes have the potential to be used for periodontal regeneration. It has the necessary characteristics of a GTR membrane like biocompatibility, space maintaining ability, and tissue integration. Among the various antimicrobial agents loaded in the PLA membranes, tetracycline-loaded membranes exhibited minimal cellular toxicity against HeLa cells; at the same time showing significant activity against a pathogenic bacterium.

Enhancing guided tissue regeneration of periodontal defects by using a novel perforated barrier membrane

BACKGROUND

The present study was designed to determine whether exclusion of the gingival connective tissue (CT) and periosteum with contained stem cells has a positive or negative effect on periodontal regeneration by comparing the use of a novel modified perforated collagen membrane with a traditional cell occlusive barrier membrane.

METHODS

Twenty non-smoking patients with severe chronic periodontitis were included in the study. Single deep intrabony defects from each of the patients were randomly divided into two groups, as follows: occlusive bovine collagen membranes (OM control group, 10 sites) and modified perforated bovine collagen membranes (MPM test group, 10 sites). Plaque index, gingival index, probing depth (PD), clinical attachment level (CAL), defect base level (DBL), and crestal bone level (CBL) were measured at baseline and were reassessed at 6 and 9 months after therapy to evaluate the quantitative changes in the defect.

RESULTS

At 6- and 9-month observation periods, the MPM-treated sites showed a statistically significant improvement in PD reduction and CAL gain compared with the OM control group. DBL was significantly reduced with no significant difference between the two groups at 6- and 9-month observation periods. CBL was significantly higher in the MPM group when compared with that of the OM group at both observation periods. The postoperative differences between the two groups were 2 and 1.7 mm at 6 and 9 months, respectively, in favor of the MPM-treated sites.

CONCLUSIONS

The present study demonstrated enhanced clinical outcomes when using novel MPMs compared to OMs in guided tissue regeneration procedures. These results may be affected by the penetration of gingival CT contained stem cells and periosteal cells and their differentiation into components of the attachment apparatus.

Comparative evaluation of guided tissue regeneration with use of collagen-based barrier freeze-dried dura mater allograft for mandibular class 2 furcation defects (a comparative controlled clinical study)

AIM

The aim of periodontal surgery is complete regeneration. The present study was designed to evaluate and compare clinically soft tissue changes in form of probing pocket depth, gingival shrinkage, attachment level and hard tissue changes in form of horizontal and vertical bone level using resorbable membranes.

MATERIALS AND METHODS

Twelve subjects with bilateral class 2 furcation defects were selected. After initial phase one treatment, open debridement was performed in control site while freezedried dura mater allograft was used in experimental site. Soft and hard tissue parameters were registered intrasurgically. Nine months reentry ensured better understanding and evaluation of the final outcome of the study.

RESULTS

Guided tissue regeneration is a predictable treatment modality for class 2 furcation defect. There was statistically significant reduction in pocket depth as compared to control (p < 0.01). There is statistically significant increase in periodontal attachment level within control and experimental sites showed better results (p < 0.01). For hard tissue parameter, significant defect fill resulted in experimental group, while in control group, less significant defect fill was found in horizontal direction and nonsignificant defect fill was found in vertical direction.

CONCLUSION

The results showed statistically significant improvement in soft and hard tissue parameters and less gingival shrinkage in experimental sites compared to control site.

CLINICAL SIGNIFICANCE

The use of FDDMA in furcation defects helps us to achieve predictable results. This cross-linked collagen membrane has better handling properties and ease of procurement as well as economic viability making it a logical material to be used in regenerative surgeries.

Tissue reactions to suture materials in the oral mucosa of beagle dogs

Purpose

The objective of this study was to compare and evaluate the inflammatory responses of three widely used suture materials in the keratinized gingiva and buccal mucosa of beagle dogs.

Methods

Silk, polyglycolic acid, and nylon sutures were placed within the mandibular keratinized gingiva and maxillary buccal mucosa of four male beagle dogs. Biopsies were taken 3, 7, and 14 days after suturing. Specimens were prepared with hematoxylin-eosin stain for evaluation under a light microscope.

Results

The suture materials placed in the oral mucosa elicited more inflammatory reactions than did those placed in the keratinized gingiva. The multifilament suture materials caused more inflammatory tissue reactions than did the monofilament suture materials in the oral mucosa.

Conclusions

If oral hygiene is well maintained and suture materials are placed in the keratinized gingiva, silk, nylon, and polyglycolic acid are considered to be proper suture materials for oral surgery. However, it is advisable to use monofilament suture materials if the suture site is within the oral mucosa.

The bone formation capabilities of the anorganic bone matrix-synthetic cell-binding peptide 15 grafts in an animal periodontal model: a histologic and histomorphometric study in dogs

BACKGROUND

The aim of this study is to verify the regenerative potential of particulate anorganic bone matrix-synthetic peptide-15 (ABM-P-15) in class III furcation defects associated or not with expanded polytetrafluoroethylene membranes.

METHODS

Class III furcation defects were produced in the mandibular premolars (P2, P3, and P4) of six dogs and filled with impression material. The membranes and the bone grafts were inserted into P3 and P4, which were randomized to form the test and control groups, respectively; P2 was the negative control group. The animals were sacrificed 3 months post-treatment.

RESULTS

Histologically, the complete closure of class III furcation defects was not observed in any of the groups. Partial periodontal regeneration with similar morphologic characteristics among the groups was observed, however, through the formation of new cementum, periodontal ligament, and bone above the notch. Histologic analysis showed granules from the bone graft surrounded by immature bone matrix and encircled by newly formed tissue in the test group. The new bone formation area found in the negative control group was 2.28 + or - 2.49 mm(2) and in the test group it was 6.52 + or - 5.69 mm(2), which showed statistically significant differences for these groups considering this parameter (Friedman test P <0.05). There was no statistically significant difference among the negative control, control, and test groups for the other parameters.

CONCLUSIONS

The regenerative potential of ABM-P-15 was demonstrated through new bone formation circumscribing and above the graft particles. The new bone also was accompanied by the formation of new cementum and periodontal ligament fibers.

Synthesis of a tissue-engineered periosteum with acellular dermal matrix and cultured mesenchymal stem cells

Periosteal grafts can aid in bone repair by providing bone progenitor cells and acting as a barrier to scar tissue. Unfortunately, these grafts have many of the same disadvantages as bone grafts (donor site morbidity and limited donor sites). In this article, we describe a method of synthesizing a periosteum-like material using acellular human dermis and osteoblasts or mesenchymal stem cells (MSC). We show that osteoblasts readily attach to and proliferate on the acellular human dermis in vitro. In addition, osteoblasts retained the potential for differentiation in response to bone morphogenetic protein stimulation. Cells grown on the acellular human dermis were efficiently transfected with adenoviruses with no evidence of cellular toxicity. To assess for in vivo cell delivery and bone-forming potential, the acellular human dermis was seeded with green fluorescent protein (GFP)-positive MSCs, transfected with bone morphogenetic protein 2, wrapped around the adductor muscle in syngeneic mice, and used to treat critical-sized mandibular defects in nude rats. After 3 weeks, GFP-positive cells were still present, and bone had replaced the interface between the muscle and the constructs. After 6 weeks, critical-sized bone defects had been successfully healed. In conclusion, we show that an acellular human dermis can be used to synthesize a tissue-engineered periosteum capable of delivering cells and osteoinductive proteins.

Periodontal ligament stem cell-mediated treatment for periodontitis in miniature swine

Periodontitis is a periodontal tissue infectious disease and the most common cause for tooth loss in adults. It has been linked to many systemic disorders, such as coronary artery disease, stroke, and diabetes. At present, there is no ideal therapeutic approach to cure periodontitis and achieve optimal periodontal tissue regeneration. In this study, we explored the potential of using autologous periodontal ligament stem cells (PDLSCs) to treat periodontal defects in a porcine model of periodontitis. The periodontal lesion was generated in the first molars area of miniature pigs by the surgical removal of bone and subsequent silk ligament suture around the cervical portion of the tooth. Autologous PDLSCs were obtained from extracted teeth of the miniature pigs and then expanded ex vivo to enrich PDLSC numbers. When transplanted into the surgically created periodontal defect areas, PDLSCs were capable of regenerating periodontal tissues, leading to a favorable treatment for periodontitis. This study demonstrates the feasibility of using stem cell-mediated tissue engineering to treat periodontal diseases.

Guided Tissue Regeneration, Barrier Membranes and Reconstruction of the Cleft Maxillary Alveolus

The use of barrier membranes for bone regeneration is especially beneficial in the case of severely affected soft tissue. One useful indication may be the formation of an effective shell for bone grafts in maxilla cleft defect reconstruction. When selecting a proper material for clinical use, one must consider the safety record, the resorption time and route of elimination, the time of the maintained barrier function, the necessary time of mechanical strength, and costs. Two resorbable collagen membranes, one of single-layer and one of double-layer material, were tested in vitro and in vivo. The tested single-layer membrane is less expensive, but it is also less handling than the double-layer membrane. In vitro, samples were incubated in simulated surgical wound. A complete unambiguous picture of disintegration was not proved histologically in either material in six investigation terms (1-6 weeks). In vivo the effect of the assessed membranes was verified on a group of patients (N = 45) with a cleft. Materials were applied in the reconstruction of the alveolar defect by cancellous bone grafts. The influence on the course of healing was not stated as statistically significant. However, with respect to the costs of double layer membrane, this material was used in the most severe cases.

Treatment of Class III Furcation Defects With Expanded Polytetrafluoroethylene Membrane Associated or Not With Anorganic Bone Matrix/Synthetic Cell-Binding Peptide: A Histologic and Histomorphometric Study in Dogs

BACKGROUND

Up until now, no predictable periodontal regeneration of Class III furcation defects has been demonstrated after treatment with different available techniques. Recently, a bone graft enriched with a peptide was developed and has shown satisfactory results when applied in intrabony defects. The aim of this study was to compare the use of expanded polytetrafluoroethylene (ePTFE) membrane associated (test group) or not (control group) with anorganic bovine-derived bone matrix (ABM)/synthetic peptide, in the treatment of Class III furcation defects in dogs.

METHODS

Six mongrel dogs were used in this study, and the second and fourth mandibular lower premolars were extracted. Class III furcation defects were surgically created in the third premolars and filled with impression material. Afterwards, the defects were surgically assessed for debridement and root planing. Teeth were randomly assigned into test and control groups. The membranes were removed after 4 weeks, and the animals were sacrificed 12 weeks later.

RESULTS

Comparisons between groups by the Wilcoxon signed rank test showed no statistically significant differences in the parameters evaluated. In the control group, a new bone area (NBA) of 41.71%+/-24.07%, connective tissue area (CTA) of 36.34%+/-15.50%, and epithelium tissue area (ETA) of 9.39%+/-5.85% were observed. The new cementum extension (NCE) was 24.16%+/-13.18%. The test group presented an NBA of 31.84%+/-12.58%, CTA of 47.72%+/-11.33%, ETA of 9.17%+/-6.81%, and an NCE of 30.13%+/-16.43%.

CONCLUSION

There was no statistically significant difference between the two therapies: ePTFE membrane associated with ABM/synthetic peptide flow or ePTFE membrane only.

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.

Effects of bone morphogenetic protein-6 on periodontal wound healing in a fenestration defect of rats

BACKGROUND

Bone morphogenetic proteins (BMPs) may play significant roles in bone formation. The ability of BMP-6 to promote wound healing has been chosen as the subject of this investigation. In this study, a synthetic rat BMP-6 polypeptide was applied to a periodontal fenestration defect in rats to elucidate the effects of BMP-6 on periodontal wound healing.

MATERIAL AND METHODS

Following surgery to create a bony window on the buccal aspects of mandibular molar roots, 24 male Sprague Dawley rats were divided into four groups according to BMP application (0, 1, 3 and 10 microg, respectively). Animals were killed after 28 days and the mandible taken for histological examination. Histometric measurements were performed on sections selected from three levels (coronal, middle and apical levels; with 240 microm apart from the central) of the defect. New bone and cementum formation (including area and thickness) were analyzed and compared.

RESULTS

In general, minimal new bone was observed on the surgically created defects in the non-BMP group, whereas a complete osseous healing occurred in all BMP-6 treated animals. New bone formation (both in area and thickness) was significantly influenced by both the dosage and the examining level, whereas new cementum formation was affected by dosage only. An increase in bone and cementum formation was noted in all three BMP groups when compared with the control group at all examined levels. Among the BMP groups, greatest new bone and cementum formation were noted in the 3 microg group. New cementum thickness increased on the cementum surfaces of the defects compared with the dentinal surfaces in all study groups.

CONCLUSION

An increase in new bone and cementum formation was noted after applying a synthetic BMP-6 polypeptide to a periodontal fenestration defect in rats. Therefore, we suggest that BMP-6 may play a certain role in periodontal regeneration.

Morphometric Analysis of the Furcation Anatomy of Mandibular Molars

BACKGROUND

Successful treatment of molar furcation defects remains a challenge in clinical practice. Knowledge of anatomic factors facilitates predictable management of furcation involvement lesions. The degree of success in managing furcation involvement is inversely related to the horizontal probing depth. The depth of the horizontal component of attachment loss can vary depending on the external tooth-surface reference points used. However, the anatomical factors affecting horizontal component of attachment loss have not been previously assessed. Therefore, this study determined the bucco-lingual measurements of the cemento-enamel junction and the mesial and distal roots and at the level of root separation.

METHODS

One hundred extracted permanent human mandibular first (N = 50) and second (N = 50) molars were studied. Four horizontal bucco-lingual widths were measured with calibrated calipers: 1) furcation entrance/roof (FE); 2) cemento-enamel junction level (CEJ); 3) mesial root width (MRW); and 4) distal root width (DRW).

RESULTS

The mean widths at FE, CEJ, MRW, and DRW were, respectively, 5.53 +/- 0.45 mm, 8.71 +/- 0.54 mm, 8.57 +/- 0.54 mm, and 7.97 +/- 0.65 mm in the first molars and 5.61 +/- 0.65 mm, 8.40 +/- 0.65 mm, 7.95 +/- 0.88 mm, and 7.16 +/- 0.84 mm in the second molars. Analysis of variance revealed significant differences between FE and the other variables tested. The results showed that the bucco-lingual width of the furcation roof is considerably shorter than the MRW and DRW. The difference in the mean bucco-lingual dimension between FE and the other measurements occurred in all teeth evaluated and varied between 0.7 and 4.30 mm.

CONCLUSIONS

Our findings demonstrate that clinical measurements of horizontal probing depth that use the external surfaces of roots as reference points overestimate the true anatomical component of furcation involvement in mandibular molars. Conversely, positive treatment outcomes in these teeth may be underestimated. This has implications not only for clinical practice but also for clinical research studies evaluating treatment outcomes.

Polymer-assisted regeneration therapy with Atrisorb barriers in human periodontal intrabony defects

AIM

This study compared clinical results of 40 periodontal osseous defects treated by two types of absorbable barrier materials.

MATERIAL AND METHODS

Thirty patients (23 males and seven females) suffering from moderate to advanced periodontitis (with comparable osseous defects) were randomly assigned to receive either Atrisorb barrier (n = 22; group A) or Resolut XT barrier (n = 18; group B) therapy. Periodontal phase I treatment and oral hygiene instruction were performed before periodontal surgery. Papillary preservation, partial thickness flap, citric acid root conditioning, and decortication procedures were applied during the operation. Bone defects were filled with demineralized freeze-dried bone allograft and minocycline mixture (4:1 ratio). Postoperative care included 0.10% chlorhexidine rinse daily and antibiotic medication for 2 weeks. Clinical assessments including probing depth (PD), clinical attachment level (CAL), gingival recession (GR), plaque index (PII), gingival index (GI), and radiographic examinations were taken at the baseline, preoperatively and at 3 and 6 months after regenerative surgery.

RESULTS

Six months following therapy, both Atrisorb and Resolut XT groups had achieved comparable clinical improvement in pocket reduction (3.9 versus 4.4 mm), attachment tissue gain (clinical attachment gain; 3.5 versus 3.6 mm), and reduction in the GI and in the PII. Within-group comparisons showed significant attachment gain and pocket reduction between baseline data and those at both 3 and 6 months postoperatively (p < 0.01). There were no statistically significant differences in any measured data between groups A and B.

CONCLUSIONS

The results of this study indicate that a comparable and favorable regeneration of periodontal defects can be achieved with both Atrisorb and Resolut XT barriers. Further long-term study and histologic observations of tissue healing are needed to evaluate whether Atrisorb is promising for clinical use.

Tissue response to a membrane of demineralized bovine cortical bone implanted in the subcutaneous tissue of rats

The treatment of persistent bone defects has encouraged the search for proper techniques or bone substitutes. In Dentistry, a common problem in the treatment of periodontal bone defects is the growth of tissues within the lesion, such as the junctional epithelium, which impair regeneration of these tissues. Guided tissue regeneration (GTR), based on the separation of the tissues by means of membranes or barriers, was developed in an attempt to improve periodontal regeneration. The aim of this study was to histologically evaluate the tissue response to a membrane of demineralized bovine cortical bone implanted in the subcutaneous tissue of rats. The study periods were 1, 3, 7, 15, 30 and 60 days after implantation. Analysis of the histological sections demonstrated a moderate to intense inflammatory response at 1 and 3 days, moderate at 7 and 15 days, and almost absent at 30 and 60 days. Resorption of the membrane began 15 days after implantation, and at 60 days only remnants could be detected in some animals. We concluded that the demineralized bovine cortical bone membrane was well tolerated by the tissues and is completely resorbed after 30-60 days by mononuclear cells and multinucleated giant cells, which disappear upon completion of the process.

Cellular inflammatory response to porcine collagen membranes

OBJECTIVES

The purpose of this study was to assess local inflammatory changes associated with the implantation of three different porcine collagen membranes having potential use in periodontal regeneration.

METHODS

Materials were implanted subcutaneously into prepared sites along the dorsal skin surface of 60 female Wistar rats. Saline and turpentine were used as negative and positive controls, respectively. Animals were killed and biopsies obtained after 3 d, and at 1, 2, 4, 6, and 8 weeks after membrane implantation. A panel of six monoclonal antibodies was used to identify circulating monocytes (ED1), resident tissue macrophages (ED2), lymphoid macrophages (ED3), Ia-antigen expression (OX6), T-lymphocytes (OX19), and B-lymphocytes (OX33). Cells identified by each antibody were subjected to quantitative immunocytochemistry to compare any differences present among groups. Sera obtained 8 weeks after grafting were used in immunoblotting assays to detect the presence of systemic antiporcine antibodies.

RESULTS

We found that the mononuclear cell subsets associated with implantation of porcine collagen membranes were similar to those obtained with saline administration. On the other hand, the use of turpentine resulted in an inflammatory infiltrate characterized by significantly higher numbers of all six monoclonal cell subsets at all time periods evaluated, compared to either saline or any of the membranes (P < 0.001).

CONCLUSIONS

The collagen membranes do not appear to be associated with a significant local inflammatory response, nor a systemic immune response, and thus appear to be well tolerated, rendering them useful in periodontal regeneration.

Guided tissue regeneration in human Class II furcation defects using a diphenylphosphorylazide-cross-linked collagen membrane: a consecutive case series

BACKGROUND

Several bioabsorbable collagen membranes are either currently available or under investigation for use in guided tissue regeneration (GTR) procedures. The aim of this 12-month reentry study was to evaluate a diphenylphosphorylazide (DPPA)-cross-linked bovine type I collagen membrane in the healing of mandibular Class II furcation defects. The DPPA technique prevents the inclusion of foreign cytotoxic cross-linking substances in the reticulated molecules, thus providing a more biocompatible product.

METHODS

Forty non-smoking periodontally compromised adult subjects volunteered for this study, and one defect was randomly selected in each patient. At baseline, plaque index (PI), gingival index (GI), probing depth (PD), gingival margin location (GML), clinical attachment level (CAL), and width of the attached gingiva (AG) were measured. Intrasurgical hard tissue measurements consisted of the vertical open probing attachment level (V-OPAL) and horizontal open probing attachment level (H-OPAL), as well as furcation entrance width (FW) and height (FH) and subclassification of defects according to vertical bone loss. All soft tissue measurements were repeated 12 months after membrane placement using conservative flap reentry surgeries; hard tissue parameters were also assessed at this time.

RESULTS

DPPA-cross-linked collagen membranes demonstrated good handling characteristics, and no postoperative adverse tissue reactions or clinically detectable localized allergic responses were observed. GI and PI remained low during the entire study period. When the one year reentry values were compared to the baseline measurements, a significant reduction in PD (1.9 +/- 1.4), FW (2.1 +/- 1.7), FH (2.9 +/- 1.6), and gain in CAL (1.7 +/- 1.5), V-OPAL (2.1 +/- 1.9), and H-OPAL (4.7 +/- 1.4) were observed (P < or = 0.05). However, there were no significant differences in GML or AG. Hard tissue improvements resulted in the complete closure of 30% (12) of the defects, and transformation of 67.5% (27) of the defects to Class I, while one defect remained a Class II (2.5%).

CONCLUSIONS

Based on this 12-month clinical reentry study, a DPPA-cross-linked collagen membrane could be beneficial in GTR treatment of Class II mandibular furcation involvements, both in terms of soft and hard tissue improvements.

Comparison of Th1/Th2 cytokine profiles of initial wound healing of rats induced by PDCM and e-PTFE

Because periodontal regeneration is vital in the modern treatment of periodontal defects, artificial membranes have become a key component for predictable outcomes. Herein a new ranking system to analyze the expression of different cytokines around regenerative membranes is introduced. Porcine dermal collagen membranes (PDCMs) and GORE-TEX (e-PTFE) membranes were used for implantation in a Sprague Dawley rat model. Tissue samples were harvested at three time intervals (7, 10, and 14 days); then an immunohistochemical ranking process was conducted to determine the intensity of the selected Th1/Th2 cytokines [Th1: interleukin-2 (IL-2) and interferone-gamma (IFN-gamma); Th2: IL-4, IL-10, and IL-13]. The results show that the intensities of IL-2 cytokine in PDCM groups were slightly higher than those of e-PTFE groups but without statistical significance. The level of interferon-gamma in PDCM groups was lower than that of e-PTFE groups, but also without significant differences. However, expressions of Th2 cytokines (IL-4, IL-10, and IL-13) induced by e-PTFE were generally higher than those of PDCM and control groups at all times (Mann-Whitney U test, p < 0.05). In a comparison of the mean ratio of IL-2/IL-4 with the use of the Mann-Whitney U test, data for the PDCM group were generally higher than those of the e-PTFE group, with statistical significance at all time intervals (p < 0.05). A descending order of the intensity ratio of IL-2/IL-4 was PDCM groups > control groups > e-PTFE groups. These findings indicate that the cytokine profiles of PDCM, in connection with the GTR technique, demonstrate a higher trend toward Th1-dominated responses and may protect against periodontal tissue destruction, as compared to the Th2-dominated responses of e-PTFE.

Medical grade calcium sulfate hemihydrate versus expanded polytetrafluoroethylene in the treatment of mandibular class II furcations

BACKGROUND

Guided tissue regeneration (GTR) techniques have been reported to enhance bone regeneration of molar furcation defects. The current trends in therapy encourage the use of a bioabsorbable barrier. The efficacy of the bioabsorbable barrier needs to be equal to, if not better than, the non-absorbable barrier.

METHODS

This clinical study compared the bone regeneration capacity of a commonly used GTR procedure (demineralized freeze-dried bone allograft [DFDBA] and an expanded polytetrafluoroethylene [ePTFE] membrane) to DFDBA and an exclusion barrier of medical grade calcium sulfate hemihydrate [MGCSH]). Thirteen pairs of mandibular molar Class II furcation defects were evaluated in 13 patients. Clinical measurements of keratinized gingival width, probing depth, and recession were recorded prior to treatment. Following flap elevation and furcation defect debridement, an occlusal reference stent and periodontal probes were used to measure vertical, horizontal, and intrabony defect dimensions to the nearest millimeter. Paired defects were randomly assigned to receive either DFDBA/ePTFE or DFDBA/MGCSH. At 6 months, study sites were surgically re-entered and the treated furcations were debrided to a firm bone surface. Intraoperative measurements were repeated. Clinical measurements were repeated at 12 months.

RESULTS

The MGCSH-treated furcations demonstrated mean probing depth reduction between baseline and 6 months (1.00 +/- 0.82 mm, P<0.05) and baseline and 12 months (1.31 +/- 0.85 mm, P<0.05). There was no statistically significant change in probing depth in the ePTFE group at any time interval. The horizontal defect fill was significantly greater for ePTFE (36.7%) versus MGCSH (23.8%) (P<0.02).

CONCLUSIONS

In selected defects, improved clinical measurements were achieved with DFDBA/MGCSH as well as DFDBA/ePTFE. Both treatments obtained significant horizontal defect fill at 6 months. DFDBA/ePTFE showed a significantly greater horizontal defect fill compared to DFDBA/MGCSH. Attachment level gains achieved with MGCSH held for 12 months, whereas ePTFE attachment level gains did not.

Comparative histologic analysis of coronally advanced flap with and without collagen membrane for root coverage

BACKGROUND

Guided tissue regeneration (GTR)-based root coverage has been utilized to correct gingival recession defects with promising results. However, limited histologic information is available. Therefore, the aims of this study were to clinically and histologically evaluate the efficacy of GTR-based root coverage using collagen membrane (GTRC) and to compare the healing response to that of coronally advanced flaps (CAF).

METHODS

Standardized gingival recession defects were surgically created on the labial surfaces of the maxillary cuspids of 8 mongrel dogs. Plaque was allowed to accumulate for 8 weeks to develop a plaque-infected recession defect. Full-mouth scaling and root planing was then performed coincident with 4 weeks of oral hygiene. Defects were randomly assigned to receive either GTRC or CAF surgery. Four dogs each were sacrificed at 4 and 16 weeks post-treatment. Clinical measurements included: percent root coverage, the amount of keratinized gingiva (KG), and probing depth (PD). Sulcular depth, junctional epithelium and connective tissue attachment, new cementum formation, and new bone formation were evaluated histomorphometrically.

RESULTS

Clinically, both treatments (CAF and GTRC) achieved statistically significant (P <0.05) root coverage compared to baseline. KG was significantly increased in CAF-treated sites at 16 weeks, while no significant differences were found for other clinical parameters between treatments. Histometrically, GTRC showed a statistically significant increase of new attachment and newly formed connective tissue when compared to CAF at 16 weeks.

CONCLUSION

Within the limits of this preclinical study, both GTRC and CAF can be successfully used for the treatment of gingival recession defects.

Combined periodontal regenerative technique in human intrabony defects by collagen membranes and anorganic bovine bone. A controlled clinical study

BACKGROUND

Combined periodontal regenerative technique (CPRT) is a surgical procedure that combines the use of barrier membranes with a filling material in the treatment of periodontal defects. The effectiveness of CPRT has been evaluated in many studies in comparison to GTR with membranes alone, but conflicting results have been obtained by different clinicians, particularly in the treatment of intrabony defects. The aim of the present study was to compare CPRT to GTR with collagen membranes in the treatment of human intrabony defects characterized by a relevant 1-wall component.

METHODS

Thirty-four (34) healthy, non-smoking patients affected by moderate to severe chronic periodontitis participated in this study. Each patient had good oral hygiene and at least 1 radiographically detectable intrabony defect > or = 4 mm, with a 1-wall component of at least 50% of the defect, involving 2 tooth surfaces or more with a probing depth (PD) > or = 6 mm. Seventeen (17) subjects were randomly assigned to the test group and underwent CPRT by anorganic bovine bone and a collagen membrane, and 17 randomly assigned to the control group who received GTR with a collagen membrane alone. Pre- and post-therapy clinical parameters (probing depth [PD]; clinical attachment level [CAL]; gingival recession [GR]) and intrasurgical parameters (depth of intraosseous component [IOC]; level of the alveolar crest [ACL]) were compared between test and control groups 1 year after treatment. Vertical bone gain (VBG) from the base of the defect to the cemento-enamel junction was also evaluated in both groups.

RESULTS

At the 1-year examination, clinical and intrasurgical parameters showed statistically significant changes within each experimental group from baseline. A statistically greater CAL gain was reported in the test group (P<0.05), whereas the control group exhibited more GR and alveolar crest resorption at a statistically significant level (P<0.01). VBG was significantly greater (P<0.01) at test sites (5.23 +/- 1.30 mm) compared to controls (3.82 +/- 1.28 mm).

CONCLUSIONS

The results suggest that the use of CPRT may be preferred when bioabsorbable membranes are used to treat intrabony defects characterized by unfavorable architecture.

A comparison of porous and non-porous teflon membranes plus demineralized freeze-dried bone allograft in the treatment of class II buccal/lingual furcation defects: a clinical reentry study

BACKGROUND

The aim of this 9-month reentry study was to compare the regenerative healing using porous (P) and non-porous (NP) teflon barrier membranes plus demineralized freeze dried bone allografts (DFDBA) in Class II buccal/lingual furcation defects.

METHODS

Twenty-four patients, 13 males and 11 females, ages 38 to 75 (mean 54 +/- 10), were included in this study. Each patient had adult periodontitis and one Class II furcation defect measuring > or = 3 mm open horizontal probing depth. Twelve patients were randomly selected to receive the NP treatment and 12 received the P membrane. All defects received a DFDBA graft. Measurements were performed by a masked examiner.

RESULTS

No statistically significant differences (P>0.05) were found between NP and P groups at any time with respect to any open or closed measure. Improvement in mean open horizontal probing depth was significant for both the NP (2.33 +/- 0.78 mm) and P (2.75 +/- 0.75 mm) groups. Mean clinical attachment level gains at 9 months were significant for both NP (1.50 +/- 1.62 mm) and P (2.50 +/- 2.11 mm) groups. Seventeen of 24 defects had an intrabony component and > or = 50% fill was obtained in 100% of these defects.

CONCLUSIONS

The results of this 9-month reentry study comparing the use of porous and non-porous barrier membranes with a DFDBA graft indicate that there were no statistically significant differences between groups. Both groups showed a statistically significant improvement following the treatment of Class II furcation defects in humans.

Collagen membrane resorption in dogs: a comparative study

Guided tissue barriers using materials such as collagen are used in the hope of excluding epithelium and the gingival corium from the root surface or alveolar bone to facilitate regeneration. Convention suggests that the longer a membrane remains intact, the better the regeneration results. The purpose of this study was to determine the resorption rates of various collagen membranes in the oral cavity of dogs. Twelve adult mongrel dogs had three different collagen membranes (BioGide, AlloDerm porcine-derived, and AlloDerm human-derived) randomly inserted and secured into surgical pouches made in their palates. Full-thickness tissue punch biopsy specimens taken at 1, 2, 3, or 4 months after surgery were evaluated histologically for membrane intactness and other associated changes. At 1 month, all membranes had slight to moderate degradation. At 2 months, all membranes had moderate to severe degradation with the exception of one AlloDerm human-derived membrane that was intact. At 3 months, all membranes had severe degradation to not identifiable. At 4 months, all membranes had severe degradation to completely absent. Blood vessel penetration varied from none to moderate. Inflammation was found in only two samples. In the dog, all three tested collagen membranes showed slight to moderate degradation at 1 month and were severely degraded to completely absent at 4 months. Within the limits of transferring animal data to humans, clinicians need to be aware of these resorption rates when selecting membranes for guided tissue and bone regeneration.

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.

Comparative study of three different membranes for guided bone regeneration of rat cranial defects

The purpose of the study was to compare the efficacy of a non-resorbable polytetrafluoroethylene (e-PTFE) membrane (Gore-Tex) versus a resorbable polyglactin membrane (Vicryl) and a newly designed collagenic membrane for enhancing bone regeneration on rat skull defects. The study was conducted on 30 adult Wistar rats. On each animal, two symmetrical, 6 mm wide, full-thickness, skull defects were created in the parietal regions. The right defect was chosen as the experimental site and the left one was left empty as a control. Each experimental site was covered by an inner and outer membrane. The 30 rats were divided into three groups: In group 1 (n=10), a non-resorbable polytetrafluoroethylene (e-PTFE) membrane was used. In group 2 (n= 10), a resorbable polyglactin 910 membrane was used. In group 3 (n= 10), a collagen membrane processed from avian eggshell was used. In each group, the animals were euthanized at 60 days. The harvested specimens were processed for contact radiography and standard histological examination. The results were assessed by a Fisher's exact test. In group 1, partial bone healing was observed in seven out of 10 animals and complete in three out of 10 animals (P<0.001). In group 2, no or minimal bone healing was observed in seven out of 10 animals and partial bone healing was observed in three out of 10 animals. In group 3, no or minimal bone healing was observed in nine out of 10 cases and partial bone healing in only one animal. In conclusion, only the non-resorbable e-PTFE membrane group exhibited a favourable result in this study. This study suggests that the structure of the membrane is at least as important as its composition.

Treatment of intraosseous defects with bioabsorbable barriers alone or in combination with decalcified freeze-dried bone allograft: a randomized clinical trial

BACKGROUND

This study clinically compares the outcomes obtained from the use of a bioabsorbable barrier device in combination with demineralized freeze-dried bone allograft (DFDBA) to the results obtained from the barrier device used alone in the treatment of human intraosseous defects.

METHODS

The study consisted of 30 patients with one intraosseous periodontal defect each. The trial included defects with loss of attachment of > or = 6 mm, with a radiographically detectable defect of at least 4 mm and with at least 2 remaining osseous walls. After the hygienic phase, at baseline, probing depth (PD), clinical attachment level (CAL), and recession (REC) were measured. During open flap debridement, the defects were randomly assigned to receive either a polylactic acid (PLA) barrier in combination with DFDBA (test) or a PLA barrier alone (control). Additionally, baseline osseous intrasurgical measurements of the periodontal defect were obtained to evaluate the amount of bone regeneration. PD, CAL, and REC were remeasured at 6 and 12 months postsurgery and osseous measurements repeated at 12 months during a re-entry procedure.

RESULTS

Two-sample t-test comparisons of mean PD, CAL, and REC measurements (mm) between test (PLA+DFDBA) and control (PLA alone) groups at baseline, PLA+DFDBA: PD = 7.3, CAL = 8.1, REC = -0.7; PLA-alone: PD = 7.9, CAL = 8.4, REC = -0.5, were not statistically different (P>0.05). The following mean changes (delta) at 6 months for the test and the control groups were: decreased PD = 3.6 and 4.0 mm; gain CAL = 2.7 and 3.1 mm; and increased REC = -0.8 and -0.8 mm, respectively. At 12 months the changes for the test and control groups were: decreased PD = 3.3 and 4.1 mm; gain CAL = 2.3 and 3.2 mm; and increased REC = -0.8 and -1.0 mm, respectively. Two-sample t-test comparisons between PD, CAL, and REC changes yielded no significant differences between treatments (P > 0.05), except for the change in CAL at 12 months in favor of the control group, P = 0.008. Comparisons of osseous measurements resulted in no significant differences between groups at baseline and at 12 months (P > 0.05). The intrabony defect filled on the average 3.72 mm for the test and 4.85 mm for the control group. The experimental defects showed a 4.73 mm defect depth reduction, while the control defects reduced 5.35 mm. Re-entry measurements of osseous crest resorption were 1.1 mm for the test and 0.61 mm for the control.

CONCLUSIONS

In the intraosseous defects treated in this study, the addition of DFDBA to the GTR procedure did not significantly enhance the clinical results obtained with the GTR procedure alone.

The effect of postsurgical antibiotics and a bioabsorbable membrane on regenerative healing in Class II furcation defects

BACKGROUND

The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of postsurgical antibiotics on osseous healing in Class II furcation defects.

METHODS

Twenty-four Class II furcation defects in 24 patients were treated with either a polylactide bioabsorbable membrane, demineralized freeze-dried bone allograft (DFDBA) plus antibiotics (GBA or test group) or with a polylactide membrane and DFDBA alone (GB or control group). Twelve patients were included in each group. The antibiotic regimen consisted of ciprofloxacin 250 mg twice daily and metronidazole 250 mg tid for 1 week followed by a 7-week regimen of doxycycline hyclate 50 mg daily. Treatment was performed on either mandibular buccal or lingual, or maxillary buccal Class II furcation defects. Defects were randomly selected by a coin toss for treatment and all open and closed measurements were performed by a blinded examiner. Final open and closed measures from a stent were repeated at the 9-month second stage surgery. Power analysis to determine superiority of antibiotic treatment showed that a 12 per group sample size would yield 93% power to detect a 1.5 mm difference and 64% power to detect a 1 mm difference.

RESULTS

Mean open horizontal probing depth reductions at 9 months were greater for the GBA group than for the GB group (2.92+/-1.78 versus 2.50+/-1.62 mm); however, these differences were not statistically significant. Seven of 12 furcations (58%) in the GBA group demonstrated >50% vertical defect fill at 9 months compared to 8 of 12 furcations (67%) in the GB group. There were no significant differences in mean open horizontal probing depth reduction between smokers and non-smokers in either the GBA or GB groups. Membrane exposure did not appear to affect regenerative healing in either the GBA or GB groups.

CONCLUSIONS

The administration of postsurgical antibiotics did not produce statistically superior osseous healing of Class II furcation defects. This result may be attributable to membrane design which facilitates connective tissue ingrowth, thereby preventing bacterial downgrowth and contamination of the newly regenerated tissues.

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

BACKGROUND

The use of barrier membranes in the treatment of periodontal defects is well documented. There has been an increase in the use of bioabsorbable materials which do not require a second surgical procedure for removal. However, there are little data evaluating the efficacy of bioabsorbable membranes in the treatment of intrabony defects. The purpose of this investigation was to evaluate the regenerative potential of 2 bioabsorbable barrier membranes without the use of grafting materials in the treatment of interdental intrabony defects.

METHODS

Twenty-three 2- or 3-walled intrabony defects were treated in 19 patients with a mean age of 50.4 years. All had completed nonsurgical treatment and a period of supportive periodontal therapy. The sites were randomly chosen to receive a barrier membrane composed of type I bovine collagen (11) or a copolymer of polylactic acid (PGA/PLA;12). A pressure sensitive disc probe was used to evaluate the following criteria at baseline and re-entry: 1) occlusal surface to the apical depth of probe penetration (OS-DP); 2) occlusal surface to the gingival margin (OS-GM); 3) occlusal surface to the alveolar crest (OS-AC); and 4) occlusal surface to the base of the osseous defect (OS-BD). Full thickness mucoperiosteal flaps were reflected to expose the surgical sites. The defects were debrided of the granulomatous tissue, the root surfaces instrumented and conditioned with 4 one-minute applications of 50 mg/ml of tetracycline. The barrier membranes were adapted to cover the defects and the flaps replaced. The postsurgical healing was uneventful and similar in both treatment modalities.

RESULTS

Twenty-three sites were surgically re-entered 6 months from the time of the initial surgery. The deepest probe depth for each site was used for statistical analysis. There was a mean relative attachment gain of 2.58+/-1.90 mm for the collagen, and 2.77+/-2.13 mm for the copolymer. There was a decrease in probing depth of 3.27+/-1.91 mm and 0.69+/-1.35 mm of recession for the collagen. The PGA/PLA copolymer had 3.55+/-2.47 mm reduction in probe depth and 0.78+/-1.14 mm of recession.

CONCLUSIONS

The data indicated the bioabsorbable collagen and copolymer membranes resulted in comparable results. A larger sample size would be necessary to determine if one membrane was superior to the other.