Treatment of intrabony periodontal defects with enamel matrix derivative: a literature review

Enamel Matrix Derivative (EMD) as an Adjunct to Non-surgical Periodontal Therapy: A Systematic Review

If left untreated, periodontitis is a chronic, irreversible disease that can contribute to tooth loss. The primary objective of periodontal treatment is to arrest the progression of the disease and restore the supporting structures of the tooth. Scaling and root planing (SRP) is a common non-surgical periodontal therapy (NSPT) used to reduce inflammation, pocket depth, and clinical attachment loss. However, NSPT has limitations, notably in difficult-to-access deep pockets and molar furcations. Deep pockets (greater than 4 mm) frequently retain calculus following NSPT. To attain direct access, surgical periodontal therapy (SPT) is recommended, particularly for pockets deeper than 5 mm. Enamel matrix derivative (EMD) has emerged in recent years as a tool for periodontal regeneration when used in conjunction with NSP for infrabony defects. EMD may also have advantageous effects when combined with NSPT. The purpose of this review is to provide a thorough understanding of the effects of EMD as an adjunct to NSPT. The databases Scopus, PubMed/MEDLINE, Google Scholar, Cochrane, and Embase were systematically searched to identify relevant studies on the benefits of EMD and its use as an adjunct to NSPT. Incorporating EMD into NSPT reduces chair time, and 60% of studies demonstrated considerable benefits compared to SRP alone, according to the findings. On the basis of research, it can be concluded that EMD can be used as an adjunct to NSPT, thereby reducing the amount of time spent in the operating chair. In some cases, it can, therefore, be regarded as an alternative to surgical treatment.

Enamel Matrix Derivatives as an Adjunct to Alveolar Ridge Preservation-A Systematic Review

PURPOSE

To systematically assess the current evidence regarding the adjunctive application of enamel matrix derivatives (EMDs) during alveolar ridge preservation (ARP) following tooth extraction.

METHODS

A comprehensive literature search was conducted in MEDLINE, Cochrane Library, PsycINFO, Web of Science, Google Scholar, and Scopus to identify relevant randomized controlled clinical trials (RCTs). The primary outcome parameters of this systematic review were histomorphometric and radiographic data; secondary outcomes were the feasibility of implant placement after ARP as well as patient-related outcomes such as postoperative discomfort.

RESULTS

The search identified 436 eligible articles published from 2011 to 2022, but only five were ultimately included for data extraction (146 patients). Given the substantial heterogeneity among the included studies, no meta-analysis could be performed. The authors' qualitative analysis showed marginally improved outcomes regarding an increased percentage of new bone formation after tooth extraction and a reduction in postoperative discomfort.

CONCLUSIONS

Given the potential value of EMDs in other fields of regenerative dentistry, more consideration should be given to EMDs as an adjunctive treatment option in ARP. However, more well-controlled randomized clinical trials are necessary to evaluate the exact potential and impacts of EMDs.

Treatment of Stage III Grade C Periodontitis with Periodontal Regenerative Therapy including Guided Tissue Regeneration (GTR) and Recombinant Human Fibroblast Growth Factor (rhFGF)-2: A Case Report

This report describes a case of periodontitis treated with periodontal surgery including guided tissue regeneration (GTR) and recombinant human fibroblast growth factor (rhFGF)-2. The patient was a 54-year-old woman who visited the Tokyo Dental College Suidobashi Hospital with the chief complaint of swelling in the maxillary right gingiva. An initial examination revealed 30.4% of sites with a probing depth (PD) of ≥4 mm. The prevalence of sites with bleeding on probing was 57.7%. The plaque control record (PCR) score was 66.1%. Radiographic examination revealed vertical bone defects in the molar region. Based on these findings, the clinical diagnosis was generalized chronic periodontitis (Stage III, Grade C). Initial periodontal therapy yielded an improvement in periodontal conditions, with the PCR score reducing to 13.8%. Periodontal surgery was performed for teeth with a residual PD ≥4 mm. Guided tissue regeneration was performed on #37 and 47. A series of periodontal regenerative treatments comprising application of rhFGF-2 was performed on angular bone defects in #14, 15, 25, and 27. Open flap debridement was performed on #16, 17, 26, 36, and 46. Following evaluation, oral function was restored by placing all-ceramic crowns on #21 and 26. The patient was then placed on supportive periodontal therapy. In the present case of generalized chronic periodontitis, periodontal regenerative therapy with GTR and rhFGF-2 yielded stable periodontal conditions.

Periodontal Regenerative Therapy Using Enamel Matrix Derivative for Treatment of Generalized Severe Chronic Periodontitis: A 2-year Case Report

Here, we describe the treatment course and 2-year follow-up in a case of multiple deep intrabony defects treated with periodontal regenerative therapy. The patient was a 50-year-old woman presenting with the chief complaint of mobile teeth in the maxillary molar region. Examination at her initial visit revealed sites with a probing depth of ≥7 mm in the molar region. Radiographic examination revealed generalized bone resorption. Angular bony defects were evident in the molar region. Initial periodontal therapy was commenced based on a clinical diagnosis of generalized chronic periodontitis. At re-evaluation, an improvement was observed in periodontal conditions. Periodontal regenerative therapy with enamel matrix derivative was performed on teeth #13, 15, 24, 27, 33, 35, 37, 46, and 47. Following re-evaluation, a removable partial denture was used to replace teeth #26 and 45, and the patient placed under supportive periodontal therapy. Periodontal conditions have remained stable. Careful supportive periodontal therapy needs to be continued, however, to monitor and treat sites requiring further attention, including those with furcation involvement.

Enamel matrix derivative (Emdogain) in treatment of replanted teeth - a systematic review

OBJECTIVE

The main purpose of the present systematic review was to evaluate the efficacy of enamel matrix derivative Emdogain in healing of replanted teeth in humans.

MATERIALS AND METHODS

This review conducted in adherence to PRISMA standards and was registered in PROSPERO with registration number CRD42017062736. We graded the methodological quality of the studies by means of Cochrane's tool of risk of bias in non-randomized studies - of interventions (ROBINS-I).

RESULTS

In total, 65 studies were identified for screening, and five studies were eligible. The uneventful healing of replanted teeth was varied from 20% to 75%. Two controlled trials found Emdogain treatment significantly reduced resorption of replanted teeth and improved the healing of periodontal ligament compared with controls. Two studies showed high recurrent resorption in Emdogain treated teeth.

CONCLUSIONS

To conclude, the number of publications that met all inclusion criteria were limited and did not allow for drawing evidence for Emdogain being effective in supporting healing of replanted teeth.

* Extracellular Matrices for Bone Regeneration: A Literature Review

The gold standard material for bone regeneration is still autologous bone, a mesenchymal tissue that consists mainly of extracellular matrix (ECM) (90% v/v) and little cellular content (10% v/v). However, the fact that decellularized allogenic bone grafts often present a clinical performance comparable to autologous bone grafts demonstrates the crucial role of ECM in bone regeneration. For long, the mechanism by which bone allografts function was not clear, but recent research has unveiled many unique characteristics of ECM that seem to play a key role in tissue regeneration. This is further confirmed by the fact that synthetic biomaterials with composition and properties resembling bone ECM present excellent bone regeneration properties. In this context, ECM molecules such as glycosaminoglycans (GAGs) and self-assembly peptides (SAPs) can improve the performance of bone regeneration biomaterials. Moreover, decellularized ECM derived either from native tissues such as bone, cartilage, skin, and tooth germs or from cells such as osteoblasts, chondrocytes, and stem cells has shown promising results in bone regeneration applications. Understanding the role of ECM in bone regeneration is crucial for the development of the next generation of biomaterials for bone tissue engineering. In this sense, this review addresses the state-of-the-art on this subject matter.

Periodontal regenerative therapy with enamel matrix derivative in the treatment of intrabony defects: a prospective 2-year study

OBJECTIVE

To date, enamel matrix derivative (EMD) has been considered to be one of the few biomaterials for clinical use capable of demonstrating true periodontal regeneration. The aim of this two-center prospective clinical study was to evaluate 2-year outcome of periodontal regenerative therapy using EMD in the treatment of intrabony defects, performed as an 'advanced medical treatment' under the national healthcare system in Japan.

RESULTS

Patients with chronic periodontitis who have completed initial periodontal therapy at either of the two dental school clinics were enrolled. Each contributed at least one intrabony defect of ≥3 mm in depth. During surgery, EMD was applied to the defect following debridement. Twenty-two participants (mean age 55.2 years old, 9 men and 13 women) completed 2-year reevaluation, and a total of 42 defects were subjected to data analysis. Mean gains in clinical attachment level (CAL) at 1 and 2 years were 2.9 mm (38% of baseline CAL) and 3.1 mm (41%), respectively, both showing a significant improvement from baseline. There was also a significant reduction in probing depth (PD): mean reductions at 1 and 2 years were 3.2 and 3.3 mm, respectively. There was a progressive improvement in the mean percentages of bone fill from 26% at 1 year to 36% at 2 years. No significant difference in CAL gain at 2 years was found between 3-wall bone defects and other defect types combined. In multiple regression analysis, the baseline PD was significantly associated with CAL gain at 2 years. In this population of patients, the treatment of intrabony defects with EMD yielded clinically favorable outcomes, as assessed by periodontal and radiographical parameters, over a period of 2 years.

Influence of enamel matrix derivative on healing of root surfaces after bonding treatment and intentional replantation of vertically fractured roots

BACKGROUND/AIM

The objectives of this study were to histopathologically evaluate cementum regeneration on root surfaces when an enamel matrix derivative (EMD) was used to bond a vertically fractured root and to evaluate the effectiveness of EMD in inhibiting root resorption.

MATERIAL AND METHODS

A total of 40 roots from 24 maxillary premolars in beagles were used. The root was vertically fractured using a chisel and mallet. Super-Bond was then used to bond the fractured root. In the experimental group, the root surface was treated with ethylenediaminetetraacetic acid and an EMD. The control group received no treatment. The root was then replanted in its original location. Histopathological observation and measurement using image-analyzing software were carried out after 8 weeks.

RESULTS

In the experimental group, shallow resorption cavities developed on the root planed surfaces with new acellular cementum appearing over them. In the control group, no new cementum was seen on the planed surfaces, and there was connective tissue joining the roots. In some of the samples, resorption and multinucleated giant cells were seen. The experimental group showed a significantly larger volume of cementum formation (P < 0.001), and the volume of root resorption was significantly smaller (P = 0.004).

CONCLUSION

When bonding and replanting tooth roots after a vertical fracture, the application of EMD was effective in regenerating cementum on root surfaces from which periodontal ligament had been lost in the area around the fracture line and in reducing the incidence of root resorption.

Do the clinical effects of enamel matrix derivatives in infrabony defects decrease overtime? A systematic review and meta-analysis

Previous systematic reviews have demonstrated better results with enamel matrix derivative proteins (EMDP) as compared with open flap debridement (OFD) for the management of infrabony periodontal defects (IPD). The aim of this study was to determine whether these differences vary according to the follow-up and quality of the studies. Cochrane Central Register of Controlled Trials, Medline/PubMed, Lilacs, Embase and Web of Science electronic databases were searched up to August 2013 for randomized clinical trials.Eligible outcomes were changes in probing depth (PD), clinical attachment level (CAL),gingival recession (GR) and bone changes (BC). Studies with follow-up of 12 months showed differences of 0.97 mm (CI95% 0.52 - 1.43) and 1.19 mm (CI95% 0.77 - 1.60) for PD and CAL, respectively, favorable for EMDP. Studies with follow-up ≥ 24 months presented advantages of 1.11 mm (CI95% 0.74 -1.48) for CAL and 0.83 mm (CI95% 0.19 -1.48) for PD,with use of EMDP. Considering the quality of studies, those with low risk of bias showed lower difference between groups, presenting 0.8 mm (CI95% 0.24-1.36) for CAL, favorable for EMDP and without differences for PS (0.51 mm, CI95% -0.21 - 1.23). In conclusion, follow-up time (< or > 2 years) and the risk of bias influence the results of treatment with EMDP in IPD.

Pleiotropic effects of statins on the treatment of chronic periodontitis--a systematic review

AIM

Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase and are an important group of hypolipidaemic drugs, widely used in the treatment of hypercholesterolaemia and cardiovascular disease. Some studies have shown that statins are able to modulate inflammation and alveolar bone loss.

METHODS

In order to evaluate whether statins could influence periodontal treatment, improving the clinical and radiographic parameters in chronic periodontitis, a systematic review was conducted in the databases PUBMED and BIREME, searching for articles in English and Portuguese, published between the years 2004 and 2014, using the combined keywords statin, periodontal disease, periodontitis and alveolar bone. Studies regarding the treatment of chronic periodontitis in humans, blind or double-blind, retrospective cohort or randomized controlled trials that used statins topically or systemically were selected.

RESULTS

Statins have important anti-inflammatory and immune effects, reducing levels of C-reactive protein and matrix metalloproteinases and their intermediate products, such as tumour necrosis factor-α, and are also able to inhibit the adhesion and extravasation of leukocytes, which block the co-stimulation of T cells. Statins reduce bone resorption by inhibiting osteoclast formation and lead to increased apoptosis of these cells. The effect of statins on bone formation is related to the increased gene expression of bone morphogenetic protein in osteoblasts.

CONCLUSION

Although we found biological mechanisms and clinical results that show lower alveolar bone loss and reduction of clinical signs of inflammation, further studies are needed to evaluate the clinical applicability of statins in the routine treatment of chronic periodontitis.

Two-year randomized clinical trial of enamel matrix derivative treated infrabony defects: radiographic analysis

BACKGROUND

This split-mouth, double-blind randomized controlled trial evaluated radiographic changes in infrabony defects treated with open flap debridement (OFD) or OFD associated with enamel matrix derivative (EMD) after a 24-month follow-up. The radiographic distance from the CEJ to the bottom of the defect (BD) was considered the primary outcome. CEJ-BC and defect angle were secondary outcomes.

METHODS

Ten patients presenting 2 or more defects were selected. An individualized film holder was used to take standardized radiographs of the 43 defects, at baseline and after 24 months. Images were digitized and used to measure the distances from the cemento-enamel junction (CEJ) to the alveolar crest (AC), CEJ to the bottom of the defect (BD) and infrabony defect angle. Statistical analysis was performed in SPSS for Windows (version 5.2). Paired samples t test was used to compare test and control groups and to evaluate changes within each group. The level of significance was set at α = 0.05%.

RESULTS

After 24 months, a significant crestal bone loss was observed for EMD (1.01 mm; p = 0.049) but not for OFD (0.14 mm; p = 0.622). However, no differences were detected between groups (p = 0.37). Reduction of the bone defect depth was significant for OFD (0.70 mm; p = 0.005) but not for EMD (0.04 mm; p = 0.86), while no differences were detected between them (p = 0.87). Both EMD (0.69°; p = 0.82) and OFD (5.71°; p = 0.24) showed an improvement in defect angle measurements but no significant differences were observed after 24 months or between the groups (p = 0.35).

CONCLUSION

Linear radiographic analysis was not able to demonstrate superiority of EMD treated infrabony defects when compared to ODF after 24 months.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02195765. Registered 17 July 2014.

Long-term clinical results on the use of platelet concentrate in the treatment of intrabony periodontal defects

OBJECTIVE

The purpose of this clinical investigation was to evaluate long-term results obtained with the combination of platelet pellet (PP) plus bioabsorbable barrier membrane (BM) and to compare this outcome with the results obtained using bioactive glass (BG) graft material with a BM.

MATERIALS AND METHODS

Using a split mouth design, 11 chronic periodontitis patients (power ≥ at least 80%) were randomly assigned to treatment with a combination of PP/GTR or BG/GTR in contra-lateral dentition areas. Clinical attachment level (CAL) as the primary outcome variable, calculated as the sum of probing pocket depth (PPD) and gingival recession, and radiological alveolar bone level were recorded at baseline, 6 months and 5 years.

RESULTS

There were no statistical differences between test and control defects at baseline. PPD reductions and CAL and radiological alveolar bone height gains were statistically significant between baseline and 6 months and between baseline and 5 years in both groups (p < 0.01). Six months results of frequency distribution showed that 82% of the defects attained ≥ 4 mm CAL gain in both groups, while 5 year results showed that 73% of the defects attained 2 mm ≤ CAL gain < 4 mm in the PP/BM group and 55% of the defects attained 2 mm ≤ CAL gain < 4 mm in the BG/BM group. All parameters evaluated showed no significant differences between 6 months and 5 years in both groups (p > 0.05). No statistically significant difference in any of the clinical parameters was observed at 6 months and 5 years between the groups (p > 0.05).

CONCLUSIONS

The long-term efficacy of platelet concentrate combined with a barrier membrane is similar with the combination of bioactive glass graft material and barrier membrane, suggesting that results obtained with both treatment approaches can be maintained over a period of 5 years.

Amelogenin Peptide Extract Increases Differentiation and Angiogenic and Local Factor Production and Inhibits Apoptosis in Human Osteoblasts

Enamel matrix derivative (EMD), a decellularized porcine extracellular matrix (ECM), is used clinically in periodontal tissue regeneration. Amelogenin, EMD’s principal component, spontaneously assembles into nanospheres in vivo, forming an ECM complex that releases proteolytically cleaved peptides. However, the role of amelogenin or amelogenin peptides in mediating osteoblast response to EMD is not clear. Human MG63 osteoblast-like cells or normal human osteoblasts were treated with recombinant human amelogenin or a 5 kDa tyrosine-rich amelogenin peptide (TRAP) isolated from EMD and the effect on osteogenesis, local factor production, and apoptosis assessed. Treated MG63 cells increased alkaline phosphatase specific activity and levels of osteocalcin, osteoprotegerin, prostaglandin E2, and active/latent TGF-β1, an effect sensitive to the effector and concentration. Primary osteoblasts exhibited similar, but less robust, effects. TRAP-rich 5 kDa peptides yielded more mineralization than rhAmelogenin in osteoblasts in vitro. Both amelogenin and 5 kDa peptides protected MG63s from chelerythrine-induced apoptosis. The data suggest that the 5 kDa TRAP-rich sequence is an active amelogenin peptide that regulates osteoblast differentiation and local factor production and prevents osteoblast apoptosis.

Five years clinical results following treatment of human intra-bony defects with an enamel matrix derivative: a randomized controlled trial

INTRODUCTION

Emdogain® represents an extracellular matrix derivative that controls and promotes periodontal regeneration. Several studies have demonstrated that the treatment of periodontal defects with Emdogain® leads to improvements in clinical parameters. However, long-time clinical trials establishing clinical usefulness of Emdogain® are scarce. Therefore, the present randomized split mouth, controlled study was undertaken to evaluate the effectiveness of Emdogain® as an adjunct to open flap debridement for the treatment of intra-bony defects over a period of 5 years.

MATERIALS AND METHODS

The study population consisted of 15 chronic periodontitis patients with bilateral interproximal osseous defects. The test group was treated by open flap debridement with EDTA 24% (PrefGel®) followed by enamel matrix derivative (Emdogain®). The control group was treated by open flap debridement with EDTA 24% (PrefGel®).

RESULTS

After 1 and 5 years, both the test and control groups showed significant mean PPD reduction. A greater reduction in mean Probing Pocket Depth (PPD) was observed in the test group (3.84 ± 1.05) as compared to the control group (1.92 ± 0.35). The mean Clinical Attachment Level (CAL) gain of 3.18 ± 0.87 mm was observed in the test group, while the control group displayed mean CAL gain of 1.60 ± 0.54 mm. The observed differences were found to be statistically significant in both the groups (p < 0.05). Percentage bone fill was significantly increased at 12 months post-surgery in test group (66.66 ± 7.8%) as compared to control group (31.71 ± 4.1%).

CONCLUSION

The treatment with Emdogain resulted in a significantly higher CAL gain and PPD reduction in comparison with OFD and PrefGel®.

Clinical outcome of surgical periodontal therapy: a short-term retrospective study

This study aimed to investigate retrospectively the outcome of surgical periodontal therapy. Periodontal surgeries implemented at General Dentistry, Tokyo Dental College Suidobashi Hospital during the period of April 2010 through March 2012 were subjected to data analysis. After initial periodontal therapy, 17 clinicians performed a total of 138 periodontal surgeries in 80 patients with moderate to advanced periodontitis (31 men and 49 women; mean age 54). Cases (sites) operated were as follows: open flap debridement=102, periodontal regenerative therapy=29 (17 for intrabony defects, 12 for furcation involvements) and periodontal plastic surgery=7. Enamel matrix derivative or bone graft was used for regenerative therapy. Clinical data were analyzed focusing on the comparison between open flap debridement and regenerative therapy. At 5 months after open flap debridement, mean reduction in probing depth (PD) and gain in clinical attachment level (CAL) was 3.9 mm (range -1.0-9.0) and 2.3 mm (range -1.0-9.0), respectively. The corresponding values with regenerative therapy were 4.0 mm (range 0-8.0) and 2.8 mm (-1.0-6.0), respectively. At sites with initial PD≥8 mm, a significantly greater gain in CAL was obtained with the regenerative therapy than with flap surgery (mean CAL gain 4.3 mm vs. 2.9 mm, p<0.05). Periodontal surgery performed in our clinical setting demonstrated a favorable short-term outcome. Our data suggest the efficacy of regenerative therapy, in particular for the treatment of deep pockets.

Early and late studies of EMD use in periodontal intrabony defects

BACKGROUND AND OBJECTIVE

The clinical efficacy of EMDs for the treatment of periodontal infrabony defects has been reported. However, recent publications have questioned the validity of results from early findings. Hence, the purpose of this study was to compare the results obtained from early and late studies when EMD was used as an adjunct in treating human intrabony defects during flap surgery. The aim of this meta-analysis was to evaluate the validity of results published from early studies compared with those published from later studies.

MATERIAL AND METHODS

PubMed and MEDLINE searches were performed. The evaluation period was 1997-2010 and it was divided into two groups of equal periods of time: early studies (1997-2003) and late studies (2004-2010). The clinical parameters assessed were clinical attachment level (CAL), probing pocket depth and bone gain (BG; measured as a percentage or in mm).

RESULTS

No statistically significant difference was found between the results obtained from early studies (1997-2003) and late studies (2004-2010) with regards to CAL gain, probing pocket depth reduction and BG. Nonetheless, both study periods showed a benefit for using EMD to treat periodontal infrabony defects when compared with the groups without EMD during open flap surgery.

CONCLUSIONS

The results obtained from this study failed to show any potential differences between the results published from early studies and late studies with regards to the clinical effectiveness of EMD in treating periodontal infrabony defects.

Regenerative therapy: a periodontal-endodontic perspective

Periodontal and endodontic diseases are inflammatory responses leading to periodontal and pulpal tissue loss. Regenerative therapies aim to restore the lost structures to vitality and function. Various materials and treatments methods have been used such as bone grafts, guided tissue regeneration, enamel matrix derivatives, growth and differentiation factors, and stem cells. Although the current materials and methods demonstrated adequate clinical results, true and complete biological tissue regeneration is not yet attainable. The current article reviews chronologically the materials and methods used in periodontal and endodontic regeneration highlighting their clinical success and shortcomings, and discussing future directions in regenerative therapy.

Two-year follow-up of treatment of intrabony periodontal defect with enamel matrix derivative

The aim of this retrospective clinical study was to evaluate 2-year follow-up results following regenerative periodontal surgery for intrabony defects using enamel matrix derivative (EMD). Thirteen patients (mean age: 53 years) with a clinical diagnosis of chronic periodontitis were subjected to data analysis. A total of 25 sites with intrabony defects received regenerative therapy with EMD. Follow-up continued for a minimum of 2 years. Treatment of intrabony defects with EMD yielded a statistically significant improvement in the mean values of probing depth and gains in clinical attachment level (CAL) at 2 years compared with those at baseline (p<0.001). Sites treated with EMD demonstrated a mean CAL gain of 3.4 mm and 3.2 mm at 6 months and 2 years, respectively. No statistically significant difference in gain in CAL was found between the 6-month and 2-year results. A gain in CAL of ≥3 mm from at baseline was found in 17 sites at 2 years. This gain was achieved with minimal recession of gingival margin and was sustained over a given period of time. A trend toward a progressive increase in radiopacity, suggestive of bone-fill, was observed. In summary, treatment of intrabony defects with EMD resulted in clinically favorable outcomes. The clinical improvements obtained with regenerative therapy with EMD were maintained over a period of 2 years.

Quality assessment of systematic reviews on periodontal regeneration in humans

BACKGROUND

Systematic reviews represent the highest form of evidence in the current hierarchy of evidence-based dentistry. Critical analysis of published systematic reviews may help to analyze their strengths and weaknesses and to identify areas that need future improvement. The aim of this overview is to determine and compare the quality of systematic reviews published in the field of periodontal regeneration using established checklists, such as the Assessment of Multiple Systematic Reviews (AMSTAR) guidelines.

METHODS

A systematic search was conducted to retrieve reviews on periodontal regeneration in humans. A total of 14 systematic reviews were selected using a set of inclusion and exclusion criteria. Two independent reviewers appraised the quality of the selected reviews using AMSTAR guidelines. Each article was given an AMSTAR total score, based on the number of AMSTAR criteria that were fulfilled. The quality of included reviews was further assessed using a checklist proposed in 2003.

RESULTS

Only one of the selected systematic reviews satisfied all the AMSTAR guidelines, whereas two reviews satisfied just two of the 11 items. This study shows that published systematic reviews on periodontal regeneration exhibit significant structural and methodologic variability. Quality assessment using the additional checklist further confirmed the variability in the way systematic reviews were conducted and/or reported.

CONCLUSION

Consideration of guidelines for quality assessment, such as AMSTAR, when designing and conducting systematic reviews may increase the validity and clinical applicability of future reviews.

Comparison of characteristics of periodontal ligament cells obtained from outgrowth and enzyme-digested culture methods

OBJECTIVE

Periodontal ligament (PDL) cells have an important role in periodontal regeneration. The unique characteristics of PDL cells, mainly outgrown cells derived from PDL tissue, have been investigated. Recently, mesenchymal stem cells have been obtained from PDL tissue using enzyme digestion. The differences in properties of those PDL cells cultured by the two methods (outgrowth and enzyme digestion) are unclear. The objective of this study was to investigate the characteristics of PDL cells obtained by these methods.

METHODS

PDL cells from extracted tooth were cultured using outgrowth and enzyme digest methods. Cell proliferation, colony-forming activity and differentiation capacity to osteoblast, adipocyte and chondrocyte were compared. Gene expressions for PDL cells, mesenchymal stem cells and fibroblasts were also investigated by reverse transcription polymerase chain reaction. Procollagen type I c-peptide (PIP) production was measured using an enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

PDL cells cultured by enzyme digest methods showed a higher proliferation rate, colony-forming activity and differentiation capacity into osteoblast, adipocyte and chondrocyte than those in PDL cells by outgrowth method. CD166, one of the mesenchymal stem cell markers, was slightly higher in enzyme-digested PDL than in outgrowth PDL, whilst gene expressions for type 1 collagen alpha 1 and type 3 collagen were higher in outgrown PDL cells. Moreover, outgrowth PDL exhibited higher PIP production than enzyme-digested PDL cells.

CONCLUSION

PDL cells obtained by outgrowth and enzyme digestion showed different characteristics. The enzyme digestion method yielded cells with higher proliferation rate and mesenchymal stem cell-like properties, whereas cells with fibroblast-like properties were collected in the outgrowth method. PDL cell properties by different culture methods may provide information for inventing new therapeutic uses of PDL cells.

Comparison of mesenchymal stem cells and autogenous cortical bone graft in the treatment of class II furcation defects in dogs

The purpose of this study was to compare the effectiveness of mesenchymal stem cells (MSCs) with platelet-rich plasma (PRP) as scaffold and autogenous cortical bone (ACB) graft with and without PRP in the regenerative treatment of class II furcation defects in dogs. The mandibular second, third, and fourth premolars (P2, P3, P4) and maxillary P3 and P4 of both sides in three dogs were selected for experimentation. Class II furcation defects (5 mm in height and 2 mm in depth) were surgically created. Five weeks after the first operation, scaling + root planning (group 1), PRP (group 2), ACB (group 3), combination of ACB/PRP (group 4), and combination of MSCs/PRP (group 5) treatments were performed during open flap debridement. The percentage of cementum and alveolar bone formation was evaluated by histomorphometric analysis after a healing period of 8 weeks. There was new cementum along with periodontal ligament and coronal growth of alveolar bone in all groups. Cementum formation was significantly higher in groups 3, 4, and 5 compared to the control group (P < 0.05) with no significant difference between groups 2, 3, 4, and 5. Alveolar bone formation was similar in all groups (P > 0.05). It can be concluded that periodontal regeneration with complete filling of class II furcation defects with cementum, alveolar bone, and periodontal ligament is obtained 8 weeks after ACB, ACB/PRP, and MSCs/PRP treatments; however, efficacy of none is higher than another.

Enamel matrix derivative (Emdogain(R)) for periodontal tissue regeneration in intrabony defects

BACKGROUND

Periodontitis is a chronic infective disease of the gums caused by bacteria present in dental plaque. This condition induces the breakdown of the tooth supporting apparatus until teeth are lost. Surgery may be indicated to arrest disease progression and regenerate lost tissues. Several surgical techniques have been developed to regenerate periodontal tissues including guided tissue regeneration (GTR), bone grafting (BG) and the use of enamel matrix derivative (EMD). EMD is an extract of enamel matrix and contains amelogenins of various molecular weights. Amelogenins are involved in the formation of enamel and periodontal attachment formation during tooth development.

OBJECTIVES

To test whether EMD is effective, and to compare EMD versus GTR, and various BG procedures for the treatment of intrabony defects.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE and EMBASE. Several journals were handsearched. No language restrictions were applied. Authors of randomised controlled trials (RCTs) identified, personal contacts and the manufacturer were contacted to identify unpublished trials. Most recent search: February 2009.

SELECTION CRITERIA

RCTs on patients affected by periodontitis having intrabony defects of at least 3 mm treated with EMD compared with open flap debridement, GTR and various BG procedures with at least 1 year follow up. The outcome measures considered were: tooth loss, changes in probing attachment levels (PAL), pocket depths (PPD), gingival recessions (REC), bone levels from the bottom of the defects on intraoral radiographs, aesthetics and adverse events. The following time-points were to be evaluated: 1, 5 and 10 years.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two authors. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI). It was decided not to investigate heterogeneity, but a sensitivity analysis for the risk of bias of the trials was performed.

MAIN RESULTS

Thirteen trials were included out of 35 potentially eligible trials. No included trial presented data after 5 years of follow up, therefore all data refer to the 1-year time point. A meta-analysis including nine trials showed that EMD treated sites displayed statistically significant PAL improvements (mean difference 1.1 mm, 95% CI 0.61 to 1.55) and PPD reduction (0.9 mm, 95% CI 0.44 to 1.31) when compared to placebo or control treated sites, though a high degree of heterogeneity was found. Significantly more sites had < 2 mm PAL gain in the control group, with RR 0.53 (95% CI 0.34 to 0.82). Approximately nine patients needed to be treated (NNT) to have one patient gaining 2 mm or more PAL over the control group, based on a prevalence in the control group of 25%. No differences in tooth loss or aesthetic appearance as judged by the patients were observed. When evaluating only trials at a low risk of bias in a sensitivity analysis (four trials), the effect size for PAL was 0.62 mm (95% CI 0.28 to 0.96), which was less than 1.1 mm for the overall result. Comparing EMD with GTR (five trials), GTR showed statistically significant more postoperative complications (three trials, RR 0.12, 95% CI 0.02 to 0.85) and more REC (0.4 mm 95% CI 0.15 to 0.66). The only trial comparing EMD with a bioactive ceramic filler found statistically significant more REC (-1.60 mm, 95% CI -2.74 to -0.46) at the EMG treated sites.

AUTHORS' CONCLUSIONS

One year after its application, EMD significantly improved PAL levels (1.1 mm) and PPD reduction (0.9 mm) when compared to a placebo or control, however, the high degree of heterogeneity observed among trials suggests that results have to be interpreted with great caution. In addition, a sensitivity analysis indicated that the overall treatment effect might be overestimated. The actual clinical advantages of using EMD are unknown. With the exception of significantly more postoperative complications in the GTR group, there was no evidence of clinically important differences between GTR and EMD. Bone substitutes may be associated with less REC than EMD.

IL-6 Induces Osteoblastic Differentiation of Periodontal Ligament Cells

Interleukin (IL)-6 has been considered as an osteolytic factor involved in periodontal disease. However, the function of IL-6 in osteoblastic differentiation of periodontal ligament cells is not clear. We examined the effects of IL-6 and its soluble receptor (sIL-6R) on osteoblastic differentiation of periodontal ligament cells. Osteoblastic differentiation was induced by ascorbic acid. Osteoblast markers, including alkaline phosphatase activity and Runx2 gene expression, were examined. The mechanism of action of IL-6 on osteoblastic differentiation was evaluated by insulin-like growth factor (IGF)-I production and specific inhibitors for the IL-6-signaling molecule. IL-6/sIL-6R enhanced alkaline phosphatase activity and Runx2. Alkaline phosphatase activity was reduced by anti-IGF-I antibody. Mitogen-activated protein kinase and Janus protein tyrosine kinase inhibitors diminished alkaline phosphatase induced by IL-6/sIL-6R. We conclude that IL-6/sIL-6R increases ascorbic-acid-induced alkaline phosphatase activity through IGF-I production, implying that IL-6 acts not only as an osteolytic factor, but also as a mediator of osteoblastic differentiation in periodontal ligament cells.

Stimulation of cytokines in osteoblasts cultured on enamel matrix derivative

OBJECTIVE

The purpose of this study was to evaluate the influence of enamel matrix derivative (EMD) on the release of transforming growth factor beta 1 (TGF-beta1), interleukin-6 (IL-6), insulin-like growth factor I (IGF-I), bone morphogenetic protein 2 (BMP-2), and osteoprotegerin (OPG) in human and mouse osteoblasts.

STUDY DESIGN

Human MG-63 and mouse MC3T3-E1 cells were seeded onto 6-well culture plates at an initial density of 5,000/cm(2) and grown in Dulbecco's eagle medium (DMEM) with 10% fetal bovine serum for 24 h. Then cells were cultured either with 100 microg/mL EMD added to DMEM or with DMEM only. After 2, 5, and 9 days' incubation the culture medium was collected and analyzed by enzyme-linked immunosorbent analysis. Data were analyzed using Student t test.

RESULTS

The EMD treatment significantly increased the production of IL-6 and TGF-beta1 (P < .05) at all time points. The release of OPG was also increased in mouse osteoblasts (P < .05). IGF-I and BMP-2 were not detected in both control and EMD-treated groups.

CONCLUSION

This study suggests that the stimulatory effects of EMD on tissue regeneration are mediated by the up-regulation of local mediators released by osteoblasts.

GMP-grade preparation of biomimetic scaffolds with osteo-differentiated autologous mesenchymal stromal cells for the treatment of alveolar bone resorption in periodontal disease

BACKGROUND

Periodontal disease is a degenerative illness that leads to resorption of the alveolar bone. Mesenchymal stromal cells (MSC) represent a novel tool for the production of biologic constructs for the treatment of degenerative bone diseases. The preparation of MSC differentiated into osteogenic lineage for clinical use requires the fulfillment of strict good manufacturing practice (GMP) procedures.

METHODS

MSC were isolated from BM samples and then cultured under GMP conditions. MSC were characterized phenotypically and for their differentiative potential. Cells were seeded onto collagen scaffolds (Gingistat) and induced to differentiate into osteogenic lineages using clinical grade drugs compared with standard osteogenic supplements. Alizarin Red S stain was used to test the deposition of the mineral matrix. Standard microbiologic analysis was performed to verify the product sterility.

RESULTS

The resulting MSC were negative for CD33, CD34 and HLA-DR but showed high expression of CD90, CD105 and HLA-ABC (average expressions of 94.3%, 75.8% and 94.2%, respectively). Chondrogenic, osteogenic and adipogenic differentiation potential was demonstrated. The MSC retained their ability to differentiate into osteogenic lineage when seeded onto collagen scaffolds after exposure to a clinical grade medium. Cell numbers and cell viability were adequate for clinical use, and microbiologic assays demonstrated the absence of any contamination.

DISCUSSION

In the specific context of a degenerative bone disease with limited involvement of skeletal tissue, the combined use of MSC, exposed to an osteogenic clinical grade medium, and biomimetic biodegradable scaffolds offers the possibility of producing adequate numbers of biologic tissue-engineered cell-based constructs for use in clinical trials.

The potential use of enamel matrix derivative for in situ anterior cruciate ligament tissue engineering: a translational in vitro investigation

Polyester scaffolds have been used as an alternative to autogenous tissues for the reconstruction of the anterior cruciate ligament (ACL). They are biocompatible and encourage tissue infiltration, leading to neoligament formation. However, rupture can occur, caused by abrasion of the scaffold against the bone tunnels through which it is implanted. Good early tissue induction is therefore considered essential to protect the scaffold from this abrasion. Enamel matrix derivative (EMD) is used clinically in the treatment of periodontal disease. It is a complex mix of proteins with growth factor-like activity, which enhances periodontal ligament fibroblast attachment, proliferation, and differentiation, leading to the regeneration of periodontal bone and ligament tissues. We hypothesized that EMD might, in a similar manner, enhance tissue induction around scaffolds used in ACL reconstruction. This preliminary investigation adopted a translational approach, modelling in vitro 3 possible clinical modes of EMD administration, to ascertain the suitability of each protocol for application in an animal model or clinically. Preliminary investigations in monolayer culture indicated that EMD had a significant dose-dependent stimulatory effect (p < 0.05, n = 6) on the proliferation of bovine primary synovial cells. However, pre-treating culture plates with EMD significantly inhibited cell attachment (p < 0.01, n = 6). EMD's effects on synovial cells, seeded onto ligament scaffolds, were then investigated in several in vitro experiments modelling 3 possible modes for clinical EMD administration (pre-, intra-, and post-operative). In the pre-operative model, EMD was adsorbed onto scaffolds before the addition of cells. In the intra-operative model, EMD and cells were added simultaneously to scaffolds in the culture medium. In the post-operative model, cells were pre-seeded onto scaffolds before EMD was administered. EMD significantly inhibited cell adhesion in the pre-operative model (p < 0.05, n = 6) and had no significant benefit in the intra-operative model. In the post-operative model, the addition of EMD to previously cell-seeded scaffolds significantly increased their total deoxyribonucleic acid content (p < 0.01, n = 5). EMD's stimulative effect on cell proliferation in vitro suggests that it may accelerate scaffold colonization by cells (and in turn tissue induction) in situ. However, its inhibitory effect on synovial cell attachment in vitro implies that it may only be suited to post-operative administration.

Primary flap closure combined with Emdogain�alone or Emdogain�and Cerasorb�in the treatment of intra-bony defects

OBJECTIVES

To compare clinical outcomes of three different modalities of treatment for deep intra-bony defects.

MATERIAL AND METHODS

Fifty-six patients were paralleled for clinical parameters and randomly assigned to treatment. They displayed one angular defect each with an intra-bony component > or =3 mm, probing pocket depth (PPD) and probing attachment level (PAL) > or =7 mm, and plaque index (PI) <1. Nineteen defects were treated, respectively, with enamel matrix derivative (EMD)+tricalcium phosphate (TCP) or EMD alone and 18 defects with modified Widman flap (MWF). Primary flap closure was used in all three groups. PI, gingival index, bleeding on probing, PPD, PAL, and recession (REC) were measured before and 12 months after treatment.

RESULTS

Treatment with EMD alone yielded a 3.9+/-1.3 mm PPD decrease and a 3.7+/-1.0 mm PAL gain (p<0.001), whereas EMD+beta-TCP produced a 4.1+/-1.2 mm PPD reduction and a 4.0+/-1.0 mm PAL gain (p<0.001). These outcome parameters did not differ between the two groups. REC increased by 0.7+/-1.3 mm. After MWF treatment, attachment gain was 2.1+/-1.4 mm (p<0.001) and PPD reduction was 3.8+/-1.8 mm, whereas REC increased by 1.5+/-0.7 mm (p=0.042 versus EMD).

CONCLUSION

Both EMD treatments showed similar clinical effects, with significant PAL gain and a significantly lower REC increase in comparison with MWF treatment.

Emdogain-gel stimulates proliferation of odontoblasts and osteoblasts

OBJECTIVE

The purpose of this study was to determine whether a premixed form of enamel matrix derivative (EMD), Emdogain-gel, has the same property as the original formula of EMD in stimulating the proliferation of osteoblasts and odontoblasts.

STUDY DESIGN

Osteoblast cell line (MC3T3) and odontoblast cell line (MDPC) were cultured in the 6-well culture plates and treated in 4 different groups: (1) culture medium control, (2) 100 microg/mL Emdogain-gel directly added to the culture medium, (3) culture medium with a culture plate insert, and (4) 100 microg/mL Emdogain-gel added onto a culture plate insert. The culture plate insert prevented direct contact between Emdogain-gel and the cells. After 3-day incubation, cell morphology was examined and the total cell number per well was counted. Data were analyzed using 1-way ANOVA.

RESULTS

Emdogain-gel significantly increased cell number of both osteoblasts and odontoblasts regardless the presence of the culture plate insert.

CONCLUSION

Emdogain-gel stimulates cell proliferation of odontoblasts and osteoblasts. The direct contact between Emdogain-gel and cells is not required. Heat treatment of EMD and premix with propylene glycol alginate did not change its property of releasing bioactive molecules for promoting cell proliferation.

Evaluating the quality of active-control trials in periodontal research

AIM

The increasing popularity of randomized-controlled trials (RCTs) has raised the issue of their quality. Frequently overlooked are the differences between superiority and equivalence trials. The purpose of this study was to apply specific methodological criteria to evaluate the quality of active-control trials using studies that compared guided tissue regeneration (GTR) with enamel matrix derivatives (EMD).

MATERIALS AND METHODS

Seven RCTs were identified in the literature. Standard methodological criteria and seven additional criteria for trials using active-control groups were used to evaluate the quality of the seven RCTs.

RESULTS

Two trials were considered as superiority trials. The remaining five provided no clear statement of their research aim. However, two claimed that EMD and GTR were equally effective, because their results failed to show a significant difference between EMD and GTR. Most trials did not meet the majority of the design criteria.

CONCLUSIONS

The general lack of compliance with quality criteria might place doubt on the value of these trials and may render any conclusions questionable. It is therefore important to distinguish clearly between superiority trials and equivalence trials, and to incorporate appropriate additional criteria in the design of future RCTs with active-control groups.