Dimitris Nikolidakis

Regeneration of periodontal tissues: combinations of barrier membranes and grafting materials – biological foundation and preclinical evidence: A systematic review

BACKGROUND Regenerative periodontal therapy aims to predictably restore the tooths supporting periodontal tissues and should result in formation of a new connective tissue attachment (i.e. new cementum with inserting periodontal ligament fibres) and new alveolar bone. Histologic evidence from preclinical models has demonstrated periodontal regeneration following treatment with barrier membranes, various types of grafting materials or a combination thereof. However, it is still not clear to what extent a combination of barrier membranes and grafting materials may additionally enhance the regeneration process compared with barrier membranes alone, grafting materials alone or open flap debridement. OBJECTIVES To review with a systematic approach all preclinical (i.e. animal) studies presenting histologic support for periodontal regeneration using the combination of barrier membranes and grafting materials. MATERIAL AND METHODS Based on a focused question, an electronic and manual search was conducted for animal studies presenting histological data for the effect of the combined use of barrier membranes and grafting materials on the treatment of periodontal defects. A systematic approach was followed by two independent reviewers including eligibility criotateria for study inclusion, outcome measures determination, screening method, data extraction, data synthesis and drawing of conclusions. RESULTS Ten papers completely fulfilling the inclusion criteria were selected. All relevant data from the selected papers were extracted and recorded in separate tables according to the types of periodontal defects treated (i.e. supra-alveolar defects, intrabony defects, furcation defects and fenestration defects) with the combination of barrier membranes and grafting materials. Most studies have demonstrated periodontal regeneration following the combination approach. Most studies demonstrated superior histologic healing following the combination of barrier membranes and grafting materials than following open flap debridement. Histologically superior healing following the combination of barrier membranes and grafting materials when compared with barrier membranes alone or grafting materials alone were only obtained in non-contained two wall intrabony and supraalveolar defects. CONCLUSION Within its limits the present analysis indicates that: (a) The combination of barrier membranes and grafting materials may result in histological evidence of periodontal regeneration, predominantly bone repair. (b) No additional benefits of combination treatments were detected in models of three wall intrabony, Class II furcation or fenestration defects. (c) In supra-alveolar and two wall intrabony (missing buccal wall) defect models of periodontal regeneration, the additional use of a grafting material gave superior histological results of bone repair to barrier membranes alone. (d) In one study using a supra-alveolar model, combined graft and barrier membrane gave a superior result to graft alone.

The biology of platelet-rich plasma and its application in oral surgery: literature review.

Platelet-rich plasma (PRP) is a new approach in tissue regeneration and a developing area for clinicians and researchers. It is used in various surgical fields, including oral and maxillofacial surgery. PRP is prepared from the patients own blood and contains growth factors that influence wound healing. Of these growth factors, platelet-derived growth factor, transforming growth factor, insulin-like growth factor, and epidermal growth factor play a pivotal role in tissue repair mechanisms. Although the growth factors and mechanisms involved are still poorly understood, the easy application of PRP in the clinic and its possible beneficial outcome, including reduction of bleeding, rapid soft tissue healing, and bone regeneration, hold promise for new treatment approaches. However, animal studies and human trials demonstrate conflicting results regarding the application of PRP. Therefore the aim of this literature review is to evaluate the scientific evidence regarding the use of PRP in dentistry, to describe the different bioactive substances included in PRP and their participation in the healing process, to elucidate the different techniques and available technology for PRP preparation, to review animal and human studies, to clarify risks, and to provide guidance for future research.

Treatment of class III multiple gingival recessions: a randomized-clinical trial

BACKGROUND The aim of this controlled randomized split-mouth study was to evaluate whether a modified tunnel/connective tissue graft (CTG) technique - enamel matrix derivative (EMD) combination will improve the treatment of multiple class III recession when compared with the same technique alone. MATERIALS AND METHODS Twenty healthy subjects with a mean age of 31.7 years, were enrolled for the trial in a university periodontal clinic. Patients with at least three adjacent gingival recessions on both sides of the mouth were treated with a modified tunnel/CTG technique. On the test side, an EMD was used in addition. Clinical parameters were measured at baseline, 28 days, 3, 6 and 12 months after the surgery. Results are presented at the subject level. RESULTS The mean root coverage from baseline to 1 year post-surgery was 82% for the test group and 83% for the control group. Complete root coverage was achieved at 1 year in eight (38%) of the 20 surgeries (experimental and control group). CONCLUSIONS One-year results indicate that the modified tunnel/CTG technique is predictable for the treatment of multiple class III recession-type defects. The addition of EMD does not enhance the mean clinical outcomes.

Biomaterials for promoting periodontal regeneration in human intrabony defects : a systematic review

Intrabony periodontal defects are a frequent complication of periodontitis and, if left untreated, may negatively affect long-term tooth prognosis. The optimal outcome of treatment in intrabony defects is considered to be the absence of bleeding on probing, the presence of shallow pockets associated with periodontal regeneration (i.e. formation of new root cementum with functionally orientated inserting periodontal ligament fibers connected to new alveolar bone) and no soft-tissue recession. A plethora of different surgical techniques, often including implantation of various types of bone graft and/or bone substitutes, root surface demineralization, guided tissue regeneration, growth and differentiation factors, enamel matrix proteins or various combinations thereof, have been employed to achieve periodontal regeneration. Despite positive observations in animal models and successful outcomes reported for many of the available regenerative techniques and materials in patients, including histologic reports, robust information on the degree to which reported clinical improvements reflect true periodontal regeneration does not exist. Thus, the aim of this review was to summarize, in a systematic manner, the available histologic evidence on the effect of reconstructive periodontal surgery using various types of biomaterials to enhance periodontal wound healing/regeneration in human intrabony defects. In addition, the inherent problems associated with performing human histologic studies and in interpreting the results, as well as certain ethical considerations, are discussed. The results of the present systematic review indicate that periodontal regeneration in human intrabony defects can be achieved to a variable extent using a range of methods and materials. Periodontal regeneration has been observed following the use of a variety of bone grafts and substitutes, guided tissue regeneration, biological factors and combinations thereof. Combination approaches appear to provide the best outcomes, whilst implantation of alloplastic material alone demonstrated limited, to no, periodontal regeneration.

The effect of a low dose of transforming growth factor β1 (TGF-β1) on the early bone-healing around oral implants inserted in trabecular bone

Transforming growth factor beta1 (TGF-beta1) has been shown to stimulate bone healing in several animal models and may influence bone response directly after implant installation. Aim of the present study is to investigate the effect of a low dose of TGF-beta1, on the early bone-healing around oral implants placed in trabecular bone (femoral condyle of goats). Twenty-four cylindrical screw type implants were used and TGF-beta1 in two different concentrations were applied on sixteen of them. Each animal received three implants: one Ti (control), one Ti loaded with 0.5 microg TGF-beta1 (Ti-TGF(0.5)), and one Ti loaded with 1.0 microg TGF-beta1 (Ti-TGF(1.0)). The eight animals were euthanized at 6 weeks after implantation and implants with surrounding tissue were retrieved for histological preparation and histomorphometrical evaluation. Light microscopical analysis showed the occurrence of an intervening fibrous tissue layer around about half of the TGF-beta1 loaded implants. Further, the histomorphometrical measurements revealed that the Ti implants demonstrated the highest percentage of bone-implant contact (65+/-4%), while Ti-TGF(1.0) implants showed the lowest amount (45+/-12%). The difference between these two groups was statistically significant. On basis of the results, it is concluded that a low dose of TGF-beta1 has a negative effect on the integration of oral implants in trabecular bone during the early post-implantation healing phase.

Which biomaterials may promote periodontal regeneration in intrabony periodontal defects? A systematic review of preclinical studies.

OBJECTIVE To systematically analyze the regenerative effect of the available biomaterials either alone or in various combinations for the treatment of periodontal intrabony defects as evaluated in preclinical histologic studies. DATA SOURCES A protocol covered all aspects of the systematic review methodology. A literature search was performed in Medline, including hand searching. Combinations of searching terms and several criteria were applied for study identification, selection, and inclusion. The preliminary outcome variable was periodontal regeneration after reconstructive surgery obtained with the various regenerative materials, as demonstrated through histologic/ histomorphometric analysis. New periodontal ligament, new cementum, and new bone formation as a linear measurement in mm or as a percentage of the instrumented root length were recorded. Data were extracted based on the general characteristics, study characteristics, methodologic characteristics, and conclusions. Study selection was limited to preclinical studies involving histologic analysis, evaluating the use of potential regenerative materials (ie, barrier membranes, grafting materials, or growth factors/proteins) for the treatment of periodontal intrabony defects. Any type of biomaterial alone or in various combinations was considered. All studies reporting histologic outcome measures with a healing period of at least 6 weeks were included. A meta-analysis was not possible due to the heterogeneity of the data. CONCLUSION Flap surgery in conjunction with most of the evaluated biomaterials used either alone or in various combinations has been shown to promote periodontal regeneration to a greater extent than control therapy (flap surgery without biomaterials). Among the used biomaterials, autografts revealed the most favorable outcomes, whereas the use of most biologic factors showed inferior results compared to flap surgery.

Treatment of class III multiple gingival recessions: A randomized-clinical trial: Clinical Innovation

BACKGROUND The aim of this controlled randomized split-mouth study was to evaluate whether a modified tunnel/connective tissue graft (CTG) technique - enamel matrix derivative (EMD) combination will improve the treatment of multiple class III recession when compared with the same technique alone. MATERIALS AND METHODS Twenty healthy subjects with a mean age of 31.7 years, were enrolled for the trial in a university periodontal clinic. Patients with at least three adjacent gingival recessions on both sides of the mouth were treated with a modified tunnel/CTG technique. On the test side, an EMD was used in addition. Clinical parameters were measured at baseline, 28 days, 3, 6 and 12 months after the surgery. Results are presented at the subject level. RESULTS The mean root coverage from baseline to 1 year post-surgery was 82% for the test group and 83% for the control group. Complete root coverage was achieved at 1 year in eight (38%) of the 20 surgeries (experimental and control group). CONCLUSIONS One-year results indicate that the modified tunnel/CTG technique is predictable for the treatment of multiple class III recession-type defects. The addition of EMD does not enhance the mean clinical outcomes.

Treatment of class III multiple gingival recessions: a randomized-clinical trial: Multiple class III recessions treatment

BACKGROUND The aim of this controlled randomized split-mouth study was to evaluate whether a modified tunnel/connective tissue graft (CTG) technique - enamel matrix derivative (EMD) combination will improve the treatment of multiple class III recession when compared with the same technique alone. MATERIALS AND METHODS Twenty healthy subjects with a mean age of 31.7 years, were enrolled for the trial in a university periodontal clinic. Patients with at least three adjacent gingival recessions on both sides of the mouth were treated with a modified tunnel/CTG technique. On the test side, an EMD was used in addition. Clinical parameters were measured at baseline, 28 days, 3, 6 and 12 months after the surgery. Results are presented at the subject level. RESULTS The mean root coverage from baseline to 1 year post-surgery was 82% for the test group and 83% for the control group. Complete root coverage was achieved at 1 year in eight (38%) of the 20 surgeries (experimental and control group). CONCLUSIONS One-year results indicate that the modified tunnel/CTG technique is predictable for the treatment of multiple class III recession-type defects. The addition of EMD does not enhance the mean clinical outcomes.