Clinical outcomes with bioactive agents alone or in combination with grafting or guided tissue regeneration

Partial (incomplete) removal of granulation tissue using modified minimally invasive surgical technique in treatment of infrabony defects (randomized control clinical trial)

AIM

This study aims to compare the clinical and radiographic outcomes after complete versus incomplete removal of granulation tissue (GT) during modified minimally invasive surgical technique (M-MIST) for management of periodontitis patients with deep pockets associated with infra-bony defects.

METHODOLOGY

Ten patients with a total of 14 deep non-resolving pockets (≥ 5 mm) associated with a vertical infra-bony defect were recruited for this study. They were randomized into 2 groups; a test group with incomplete removal of GT and a control group with complete removal of GT. Clinical parameters of clinical attachment level (CAL), residual probing depth (rPD) and buccal recession (Rec.) were recorded every 3 months. Radiographic periapicals were taken at baseline, 6 and 9 months. The significance level was set to 0.05.

RESULTS

None of the results showed statistical significance between the 2 groups (p > 0.05). The test group showed less CAL gain (2 ± 0.87 mm, p = 0.062), more reduction in rPD (3.1 ± 0.96 mm, p = 0.017) and more recession (0.857 ± 0.26 mm, p = 0.017) than control group CAL gain (2.4 ± 0.58 mm, p = 0.009), rPD reduction (2.9 ± 0.3 mm, p = 0.001) and recession (0.5 ± 0.34 mm, p = 0.203) respectively. Control group had linear reduction in depth defect (DD) (0.68 ± 0.287, p = 0.064) compared to an increase in DD in test group (-0.59 ± 0.5, p = 0.914).

CONCLUSIONS

No statistical significance were observed in healing parameters between complete removal of GT in M-MIST and incomplete (partial) removal of GT of deep pockets with infra-bony defects both clinically and radiographically. Further studies with larger samples are needed to confirm the results.

Demineralized dentin matrix for bone regeneration in dentistry: A critical update

Over the last few decades, several new materials and techniques have been developed for bone regeneration. Scaffolds based on demineralized dentin matrix (DDM) present an attractive option due to their availability and several animal and human studies have been conducted to ascertain their utility in regenerative dentistry. The aim of this review was to summarize the recent studies conducted on DDM and used for bone grafts. PubMed, Web of Science, and Scopus were used to search for studies published within the last 10 years. The keywords and terms used were: "demineralized dentine matrix", "bone grafting", "bone augmentation" and "guided tissue regeneration" in various combinations. Original studies (in vitro, animal and human) and systematic reviews were included in the literature search. The literature search initially identified 23 studies (16 animal studies and 7 clinical reports. Most studies included in this review indicate that DDM has demonstrated promising results in a variety of dental and regenerative medicine applications. Further studies are required to completely comprehend its characteristics and prospective applications. Future studies should also focus on optimizing the processing protocols for the production of DDM-based scaffolds.

The influence of interradicular anatomy on the predictability of periodontal regenerative therapy of furcation defects: a retrospective, multicenter clinical study

BACKGROUND

The relationship between the anatomy of the interradicular space and success in regenerative therapy of furcation defects is discussed in this paper. The goal of this retrospective, multicenter clinical study is to clinically evaluate the relationship between the interradicular conformation and regenerative therapy success with the use of a novel measurement method.

METHODS

One hundred thirty-eight radiographs of mandibular molars with furcation defects that had been treated with regenerative therapy were collected from six clinical centers. Data on the type of therapy and clinical parameters before and after treatment (follow-up of at least 12 months) were collected. The radiographs (before surgery and at least 12 months postoperatively) were measured with a visual evaluation method by a blind operator using graphics software.

RESULTS

Success, defined as a reduction in horizontal and vertical furcation involvement, decrease in probing depths, and increase in clinical attachment level, was statistically assessed on 138 regenerated molars sites and were related to clinical variables such as age, sex, center, and treatment. No correlation was found between success in regenerative therapy and the conformation of the interradicular space, measured with a visual ratio method and a standard linear measurement. At the univariate analysis, the parameters that had a correlation with success were center, extent of furcation involvement, treatment, and sex. The use of enamel matrix derivative (EMD) seemed to be the most favorable therapy, with increase in CAL gain and reduction of vertical or horizontal furcation involvement.

CONCLUSIONS

The regenerative outcome was not significantly influenced by the anatomy of furcation. The center, the degree of furcation involvement, sex, and treatment (EMD) were significantly associated with higher success of periodontal regeneration.

Minimal invasiveness in the surgical treatment of intraosseous defects: A systematic review

The modern approach to regenerative treatment of periodontal intraosseous defects should aim at maximizing the clinical outcomes while minimizing the invasiveness (pain, complications, aesthetic impairment, chair time, and costs) of the procedure. The present systematic review evaluated the effect of flap design, regenerative technology, and perioperative and postoperative adjunctive protocols on invasiveness. Overall, the results of the 13 included trials indicate that: (a) the elevation of a single (buccal or lingual) flap positively influences the intensity of postoperative pain and improves the quality of early wound healing compared with double flaps; (b) while the adjunctive use of a membrane is associated with significantly longer surgery-related chair time and higher postoperative pain, the adjunctive use of enamel matrix derivative at sites receiving a graft significantly reduces postoperative pain; also, graft materials showed no significant impact on invasiveness; (c) open flap debridement performed through the elevation of a single flap may lead to substantial clinical improvements of the lesion with reduced surgery-related chair time and costs, thus representing a promising alternative to regenerative treatment. However, for such an approach, a histological evaluation of the nature of the reconstructed tissues is still lacking, and the presurgery conditions (eg, probing depth, defect severity, and defect morphology), which may benefit in terms of invasiveness, have not yet been defined; and (d) intraoperative and postoperative low-level laser biostimulation of the defect site may favorably modulate the postoperative course.

The Use of Biocompatible Membranes in Oral Surgery: The Past, Present & Future Directions. A Narrative Review

The use of biocompatible membranes in periodontal and oral surgery is an important part of regeneration. Over the years, several different membranes have been developed, ranging from non-resorbable membranes that have to be removed in a separate procedure, to collagen membranes that completely resorb on their own, thus avoiding the need for a second surgery. Autogenous membranes are becoming increasingly popular in more recent years. These membranes can be used with a great variety of techniques in the four main hard tissue regenerative procedures: guided tissue regeneration, alveolar ridge preservation, guided bone regeneration and sinus floor augmentation. A review of the literature was conducted in order to identify the most commonly used membranes in clinical practice, as well as the most promising ones for regeneration procedures in the future. The information provided in this review may serve as a guide to clinicians, in order to select the most applicable membrane for the clinical case treated as the correct choice of materials may be critical in the procedure's success.

Human Umbilical Cord Mesenchymal Stem Cells: Current Literature and Role in Periodontal Regeneration

Periodontal disease can cause irreversible damage to tooth-supporting tissues such as the root cementum, periodontal ligament, and alveolar bone, eventually leading to tooth loss. While standard periodontal treatments are usually helpful in reducing disease progression, they cannot repair or replace lost periodontal tissue. Periodontal regeneration has been demonstrated to be beneficial in treating intraosseous and furcation defects to varied degrees. Cell-based treatment for periodontal regeneration will become more efficient and predictable as tissue engineering and progenitor cell biology advance, surpassing the limitations of present therapeutic techniques. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into several cell types when stimulated. Mesenchymal stem cells (MSCs) have been tested for periodontal regeneration in vitro and in humans, with promising results. Human umbilical cord mesenchymal stem cells (UC-MSCs) possess a great regenerative and therapeutic potential. Their added benefits comprise ease of collection, endless source of stem cells, less immunorejection, and affordability. Further, their collection does not include the concerns associated with human embryonic stem cells. The purpose of this review is to address the most recent findings about periodontal regenerative mechanisms, different stem cells accessible for periodontal regeneration, and UC-MSCs and their involvement in periodontal regeneration.

Bioactive Glasses in Periodontal Regeneration: Existing Strategies and Future Prospects-A Literature Review

The present review deals with bioactive glasses (BGs), a class of biomaterials renowned for their osteoinductive and osteoconductive capabilities, and thus widely used in tissue engineering, i.e., for the repair and replacement of damaged or missing bone. In particular, the paper deals with applications in periodontal regeneration, with a special focus on in vitro, in vivo and clinical studies. The study reviewed eligible publications, identified on the basis of inclusion/exclusion criteria, over a ranged time of fifteen years (from 1 January 2006 to 31 March 2021). While there are many papers dealing with in vitro tests, only a few have reported in vivo (in animal) research, or even clinical trials. Regardless, BGs seem to be an adequate choice as grafts in periodontal regeneration.

Immuno-histopathologic evaluation of mineralized plasmatic matrix in the management of horizontal ridge defects in a canine model (a split-mouth comparative study)

Our research aimed to investigate the effect of combining biphasic calcium phosphate (BCP) alloplast with mineralized plasmatic matrix (MPM) as compared with platelet-rich fibrin (PRF) on the quality and quantity of bone formation and maturation at surgically created horizontal critical-sized ridge defects (HRDs) in a canine model. We used a split-mouth design using the third and fourth mandibular premolars of the mongrel dogs. Twelve defects on the left side (experimental group, I) were managed with MPM composite mixed with BCP alloplast, MPM compact layer. On the right side (control group, II), another 12 defects were managed with PRF mixed with BCP alloplast, followed by the application of PRF compact strips. Finally, both were covered by a collagen membrane. Dogs were euthanized at 4, 8, and 12 weeks, and the studied defects were processed to evaluate treatment outcome, including mean percentage of bone surface area, collagen percentage, and osteopontin (OPN) immunoreaction. Our results revealed that the mean percentage of bone surface area was significantly increased in the experimental group treated with MPM at all time intervals as compared with the PRF group. Decreased collagen percentage and increased OPN immunoreactivity showed significant results in the MPM group as compared with PRF at 4 and 8 weeks postoperatively, respectively. In conclusion, MPM accelerates the formation of superior new bone quality when used in the treatment of HRDs.

Recombinant factors for periodontal intrabony defects: A systematic review and network meta-analysis of preclinical studies

The use of bioactive agents combined with osteoconductive scaffolds for the regeneration of periodontal intrabony defects has been the subject of intensive research in the past 20 years. Most studies reported that such agents, used in different concentrations, doses and combined with various scaffolds, might promote periodontal tissue regeneration, but evidence for the most effective combination of such agents is lacking. The objective of this study 13 was to rank the different combinations of recombinant human-derived growth and differentiation factors with/without scaffold biomaterial in the treatment of periodontal intrabony defects, through network meta-analysis of pre-clinical studies. The systematic review and network meta-analysis protocol was registered on the PROSPERO Systematic Review database with reference number: CRD42021213673. Relevant published articles were obtained after searching five electronic databases. A specific search strategy was followed by using keywords related to intrabony defects, regenerative materials, scaffolds and recombinant factors, and animal studies. All pre-clinical studies used for periodontal regeneration were included. The primary outcomes were: regeneration of junctional epithelium (mm), new cementum, connective tissue attachment, percentage of new bone formation (%), bone area (mm² ), bone volume density (g/cm³ ) and bone height (mm) data was extracted. The analysis was carried out using network meta-analysis methods, that is illustrating network plots, contribution plots, predictive and confidence interval plot, surface under the cumulative ranking (SUCRA), multidimensional scale ranking and net funnel plots using STATA IC statistical software. An SYRCLE's tool for assessing risk of bias was used for reporting risk of bias among individual studies. A total of N = 24 for qualitative and N = 21 studies for quantitative analysis published till 2020 were included. The cumulative total number of animals included in the control and test groups were N = 162 and N = 339, respectively. The duration of the study was between 3 and 102 weeks rhBMP-2 ranked higher in SUCRA as the agent associated with the best performance for bone volume density. rhGDF-5/TCP ranked best in the bone area (mm2), rhPDGF-BB/Equine ranked best in bone height (mm), rhBMP-2 ranked best in the percentage of new bone fill, rhBMP-2/ACS ranked best in new cementum formation, and rhGDF-5/b- TCP/PLGA ranked best in connective tissue attachment and junctional epithelium. There were no adverse effects identified in the literature that could affect the different outcomes for regeneration in intrabony defects. Various recombinant factors are effective in promoting the regeneration of both soft and hard tissue supporting structures of the periodontium. However, when considering different outcomes, different agents, associated or not with biomaterials, ranked best. Keeping into account the limited transferability of results from animal studies to the clinical setting, the choice of the most appropriate formulation of bioactive agents may depend on clinical needs and purpose.

Combination of enamel matrix derivative and hyaluronic acid inhibits lipopolysaccharide-induced inflammatory response on human epithelial and bone cells

Objectives

The aim of this study was to evaluate the in vitro effect of enamel matrix derivative (EMD) and hyaluronic acid (HA) and their synergistic combination on lipopolysaccharides (LPS)-induced inflammation in human keratinocytes and osteoblasts.

Material and methods

Cells were challenged with LPS (1 μg/ml) and cultured in the following treatment groups with EMD (30 mg/ml) and HA (30 mg/ml): LPS, EMD, HA, EMD + HA, EMD + LPS, HA + LPS, and EMD + HA + LPS. Cell viability, inflammatory cytokine expression, and cell migration were determined using colorimetric assay, quantitative real-time polymerase chain reaction (qPCR), and scratch wound healing assay, respectively.

Results

Cell viability was decreased when exposed to LPS compared to the controls. Overall, LPS treatment expressed upregulation on inflammatory cytokine tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). EMD and HA reduced up to 3.0-fold the cytokine expression caused by LPS (p < 0.05). EMD and HA statistically induced higher migration in osteoblasts and keratinocytes, respectively. Migration was impaired by LPS, whereas it significantly increased after addition of EMD and HA.

Conclusions

EMD and HA are advantageous biomaterials that individually generate strong directional migratory keratinocyte and osteoblast response. Their combination also enhances cell viability, and anti-inflammatory and migratory abilities to promote healing specially under LPS inflammatory stimulus. Future in vivo and animal research is necessary to further characterize the effect of EMD and HA on periodontal regeneration.

Clinical relevance

The use of EMD in conjunction with HA resulted in a reduction of inflammation and improvement of tissue healing at wound sites. Both biomaterials combined may potentially improve the effectiveness of bone regeneration in periodontal bone defects, pointing to the potential clinical relevance of both materials in regenerative periodontal surgery.

Cemental tear: Literature review, proposed classification and recommendations for treatment

Cemental tears are an important condition of relevance to Endodontics but are often overlooked. A cemental tear is the partial or complete detachment of the cementum from the cemento-dentinal junction or along the incremental line within the body of cementum. The limited attention received is most likely due to the limited awareness amongst dental professionals and challenges in accurately diagnosing them, resulting in misdiagnosis and erroneous treatment. The aim of this review is to describe the: (i) epidemiology and predisposing factors; (ii) clinical, radiographic and histological features and (iii) the clinical management and treatment outcomes of cemental tear. The review included 37 articles published in English that comprised eight observational studies and 29 case reports. The prevalence of cemental tears was reported to be lower than 2%; whilst the incidence remains unknown. Internal factors due to the inherent structural weakness of cementum and its interface with the dentine, and external factors that are associated with stress have been proposed as the two mechanisms responsible for the development and propagation of cemental tears. Predisposing factors that have been implicated were tooth type, gender, age, previous root canal treatment, history of dental trauma, occlusal trauma and excessive occlusal force; however, evidence is limited. Common clinical and radiographic manifestations of cemental tears resemble the presentations of primary endodontic diseases, primary periodontal diseases and combined endodontic-periodontal lesions. Clinical management tended to focus on complete removal of the torn fragments and periodontal treatment, often combined with regenerative treatment. In this article, a new classification for cemental tears is developed that consists of classes 0 to 6 and stages A, B, C and D based on the: (i) location and accessibility of the torn cemental fragment; (ii) the pattern and extension of the associated bony defect in relation to the root length and (iii) the number of root surface/s affected by the cemental tear/s and the associated bony defect. Recommendations for treatment strategies are also provided and linked to the classification to aid in streamlining the process of treatment decision making.

Electrospun core-shell nanofibers with encapsulated enamel matrix derivative for guided periodontal tissue regeneration

The osteogenic effect of a composite electrospun core-shell nanofiber membrane encapsulated with Emdogain^® (EMD) was evaluated. The membrane was developed through coaxial electrospinning using polycaprolactone as the shell and polyethylene glycol as the core. The effects of the membrane on the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) were examined using Alizarin Red S staining and qRT-PCR. Characterization of the nanofiber membrane demonstrated core-shell morphology with a mean diameter of ~1 µm. Examination of the release of fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA) from core-shell nanofibers over a 22-day period showed improved release profile of encapsulated proteins as compared to solid nanofibers. When cultured on EMD-containing core-shell nanofibers, PDLSCs showed significantly improved osteogenic differentiation with increased Alizarin Red S staining and enhanced osteogenic gene expression, namely OCN, RUNX2, ALP, and OPN. Core-shell nanofiber membranes may improve outcomes in periodontal regenerative therapy through simultaneous mechanical barrier and controlled drug delivery function.

A tissue-engineered biocomplex for periodontal reconstruction. A proof-of-principle randomized clinical study

AIM

To assess the safety/efficacy of a tissue-engineered biocomplex in periodontal reconstruction.

METHODS

Twenty-seven intrabony defects were block-randomized across three treatment groups: Group-A (N_A  = 9) received autologous clinical-grade alveolar bone marrow mesenchymal stem cells (a-BMMSCs), seeded into collagen scaffolds, enriched with autologous fibrin/platelet lysate (aFPL). In Group-B (N_B  = 10), the collagen scaffold/aFPL devoid of a-BMMSCs filled the osseous defect. Group-C (N_C  = 8) received Minimal Access Flap surgery retaining the soft tissue wall of defects identically with Groups-A/-B. Subjects were clinically/radiographically assessed before anaesthesia (baseline) and repeatedly over 12 months.

RESULTS

Quality controls were satisfied before biocomplex transplantation. There were no adverse healing events. All approaches led to significant clinical improvements (p < .001) with no inter-group differences. At 12 months, the estimated marginal means for all groups were as follows: 3.0 (95% CI: 1.9-4.1) mm for attachment gain; 3.7 (2.7-4.8) mm for probing pocket depth reduction; 0.7 (0.2-1.3) mm increase in recession. An overall greater mean reduction in the radiographic Cemento-Enamel Junction to Bottom Defect (CEJ-BD) distance was found for Groups-A/-C over Group-B (p < .023).

CONCLUSION

Radiographic evidence of bone fill was less pronounced in Group-B, although clinical improvements were similar across groups. All approaches aimed to trigger the innate healing potential of tissues. Cell-based therapy is justified for periodontal reconstruction and remains promising in selected cases.

Analysis of geometrical tomographic parameters of furcation lesions in periodontitis patients

Objectives

This study was aimed to investigate the relationship between geometric parameters of furcation lesions - maximum area of lesion opening (MALO), angle formed between the roots (ABR), lesion volume (LV) and presence and height of infra-osseous defects (IOD) - and the success of therapy with enamel matrix derivative proteins (EMD) in patients with grade C periodontitis, using cone-beam computed tomography (CBCT).

Methods

The study consisted of two groups of patients with grade C periodontitis: control (surgery) (n = 17) and test (surgery + EMD) (n = 17). Images parameters on CBCT were recorded using OnDemand3D and ITK-SNAP software.

Results

Pearson's correlation coefficient demonstrated that only IOD was statistically significant in the probing depth PD (P = 0.01), with a moderate positive correlation (R = 0.59). MALO was found to be statistically significant (P = 0.03) in the test group (surgery + EMD), with moderate negative correlation (R = -0.5).

Conclusion

The presence of infra-osseous defects and height were relevant in relation to the success of the type of treatment addressed in this study.

Periodontal infrabony defects: Systematic review of healing by defect morphology following regenerative surgery

BACKGROUND

It is thought that infrabony defect morphology affects the outcome of periodontal regenerative surgery. However, this has not been systematically investigated.

AIMS

To investigate how well defect morphology is described in papers reporting regenerative therapy of periodontal infrabony defects and to investigate its effect on clinical and radiographic outcomes.

MATERIALS AND METHODS

A search was conducted in 3 electronic databases for publications reporting clinical and radiographic outcomes of periodontal intra-bony defects after regenerative therapy, divided by defect morphology.

RESULTS

The initial search resulted in 4487 papers, reduced to 143 after first and second screening. Fifteen of these publications were suitable for a fixed-effects meta-analysis. Initial defect depth was found to influence radiographic bone gain 12 months post-surgery, while narrower angles and increased number of walls influenced both radiographic bone gain and clinical attachment level (CAL) gain at 12 months. These associations seemed to occur irrespective of biomaterials used. Risk of bias ranged from low to high.

CONCLUSION

Deeper defects with narrower angles and increased number of walls exhibit improved CAL and radiographic bone gain at 12 months post-regenerative surgery. More data are needed about other aspects of defect morphology such as extension to buccal/lingual surfaces.

Effect of Flap Design for Enamel Matrix Derivative Application in Intraosseous Defects

Objective:

To systematically review the literature addressing the focused question: What is the effectiveness of different surgical and nonsurgical procedures combined with enamel matrix derivative (EMD) on clinical, radiographic, and patient-centered outcomes in intraosseous defects?

Methods:

Electronic (Medline, Scopus, and Cochrane databases) and hand literature searches were performed for studies including at least 1 treatment arm where EMD had been applied according to 1 of the following procedures: modified Widman flap; papilla preservation variants (PPVs), including papilla preservation technique, modified papilla preservation technique, and simplified papilla preservation technique; minimally invasive variants, including minimally invasive surgical approach and minimally invasive surgical technique; single-flap variants (SFVs), including single-flap approach and modified minimally invasive surgical technique; or nonsurgical application (flapless approach). Data from 42 selected articles were used to perform a network meta-analysis, and a hierarchy of surgical and nonsurgical applications of EMD was built separately for EMD and EMD + graft based on 6- to 12-mo clinical and radiographic outcomes.

Results:

Among surgical approaches, EMD was associated with best regenerative outcomes when applied through SFVs, with a mean clinical attachment level gain of 3.93 mm and a reduction in the intrabony component of the defect of 3.35 mm. For EMD + graft, limited differences in regenerative outcomes were observed among surgical procedures. PPVs were associated with the highest residual probing depth for EMD (4.08 mm) and EMD + graft (4.32 mm).

Conclusions:

In the treatment of periodontal intraosseous defects, 1) SFVs appear to optimize the regenerative outcomes of EMD; 2) substantial regenerative outcomes can be obtained with SFVs and conservative double flaps (i.e., PPVs and minimally invasive variants) when EMD is combined with a graft; and 3) residual probing depth was higher following PPVs for EMD and EMD + graft.

Knowledge Transfer Statement:

The results of the present systematic review and meta-analysis can be used by clinicians to identify the most effective surgical or nonsurgical procedure to treat an intraosseous defect with EMD or EMD + graft. The main findings indicate that when EMD application is indicated, surgical access based on a single flap seems the most appropriate to optimize clinical outcomes. The application of EMD + graft can be effectively combined with single flaps and conservative double flaps.

Clinical and radiographic evaluation of platelet-rich fibrin as an adjunct to bone grafting demineralized freeze-dried bone allograft in intrabony defects

Background:

Several bone graft materials are popularized in the treatment of intrabony defects. Demineralized freeze-dried bone allograft (DFDBA) is widely used in the treatment of intrabony defects. Platelet-rich fibrin (PRF) is autologous blood preparation which helps in wound healing and regeneration. Hence, this study focuses on evaluation of PRF, DFDBA, and their combination in the regeneration of intrabony defects.

Materials and Methods:

A total of 39 sites with intrabony defects were randomly assigned into three groups: (Group I - Open flap debridement, Group II - DFDBA alone, and Group III- DFDBA + PRF). Parameters such as probing pocket depth (PPD), relative attachment level (RAL), and radiographic bone fill were measured at baseline, 3 months, and 6 months. Intragroup comparison at various study intervals was made using one-way ANOVA test. Intergroup comparison was made using Tukey's multiple post hoc test.

Results:

Reduction in the PPD and greater difference in RAL was observed over the study period in all the three groups with greater reduction in DFDBA + PRF group. Reduction in the radiographic defect depths was observed over the study period in all the three groups with the greatest reduction of 38.99% in the DFDBA + PRF group. However, no statistically significant difference was reported by DFDBA versus DFDBA + PRF group.

Conclusion:

Combination of DFDBA and PRF improved the clinical and radiographic parameters compared to PRF and DFDBA alone. PRF was combined with DFDBA to produce a synergistic effect for treating intrabony defects in chronic periodontitis patients.

Interests of Exosomes in Bone and Periodontal Regeneration: A Systematic Review

Periodontitis is an infectious inflammatory disease characterized by clinical attachment loss and tooth supporting tissue destruction. As exosomes demonstrated pro-regenerative ability, their use in periodontal treatment has been suggested. The aim of this systematic review is to gather and summarize the most recent data regarding exosomes to determine their potential impact in bone and periodontal regeneration. Electronic databases (Pubmed, Web of Science) were searched up to February 2020. Studies assessing the impact of exosomes administration in experimental bone and periodontal defects have been identified according to PRISMA guidelines. Among the 183 identified articles, 16 met the inclusion criteria and were included in this systematic review. Experimental bone defects were mainly surgically induced with a dental bur or distraction tools. All studies considered bone healing after exosomes administration as the primary outcome. Results showed that mesenchymal stem cells derived exosomes administration promoted bone healing and neovascularization. Nevertheless, a dose-effect relationship was observed. Exosomes administration appears to promote significantly the bone healing and periodontal regeneration. However, only a limited number of studies have been carried out so far and the optimized protocols in this context need to be evaluated.

Treatment of intrabony periodontal defects using rhFGF-2 in combination with deproteinized bovine bone mineral or rhFGF-2 alone: A 6-month randomized controlled trial

Aim

To evaluate the use of recombinant human fibroblast growth factor (rhFGF)‐2 in combination with deproteinized bovine bone mineral (DBBM) compared with rhFGF‐2 alone, in the treatment of intrabony periodontal defects.

Materials and Methods

Patients with periodontitis who had received initial periodontal therapy and had intrabony defects of ≥ 3 mm in depth were enrolled. Sites were randomly assigned to receive a commercial formulation of 0.3% rhFGF‐2 + DBBM (test) or rhFGF‐2 alone (control). Clinical parameters and a patient‐reported outcome measure (PROM) were evaluated at baseline and at 3 and 6 months postoperatively.

Results

Twenty‐two sites in each group were evaluated. A significant improvement in clinical attachment level (CAL) from baseline was observed in both groups at 6 months postoperatively. CAL gain was 3.16 ± 1.45 mm in the test group and 2.77 ± 1.15 mm in the control group, showing no significant difference between groups. Radiographic bone fill was significantly greater in the test group (47.2%) than in the control group (29.3%). No significant difference in PROM between groups was observed.

Conclusions

At 6 months, no significant difference in CAL gain or PROM between the two treatments was observed, although combination therapy yielded an enhanced radiographic outcome.

Experimental and clinical studies on regenerative periodontal therapy

The recognition of a periodontal therapy as a regenerative procedure requires the demonstration of new cementum, periodontal ligament, and bone coronal to the base of the defect. A diversity of regenerative strategies has been evaluated, including root surface conditioning, bone grafts and bone substitute materials, guided tissue regeneration, enamel matrix proteins, growth/differentiation factors, combined therapies and, more recently, tissue-engineering approaches. The aim of this chapter of Periodontology 2000 is to review the research carried out in Latin America in the field of periodontal regeneration, focusing mainly on studies using preclinical models (animal models) and randomized controlled clinical trials. This review may help clinicians and researchers to evaluate the current status of the therapies available and to discuss the challenges that must be faced in order to achieve predictable periodontal regeneration in clinical practice.

Enhancement of Healing of Periodontal Intrabony Defects Using 810 nm Diode Laser and Different Advanced Treatment Modalities: A Blind Experimental Study

BACKGROUND

Low-level laser therapy (LLLT) in the early stage of bone healing was demonstrated as a positive local biostimulative effect. It was also shown that platelet-rich fibrin (PRF) and nanohydroxyapatite alloplast (NanoHA) are effective in treating periodontal intrabony defects.

AIM

The study aimed to evaluate the combined effects of LLLT (810 nm), PRF and NanoHA on induced intrabony periodontal defects healing.

MATERIAL AND METHODS

The study was conducted on 16 defects in 8 adult male rabbits (n = 16) divided into 4 groups; Control non-treated group (C), laser irradiated control group (CL), PRF+NanoHA graft (NanoHA-Graft+PRF) treated group and laser irradiated and treated group (NanoHA-Graft+PRF+L). CT radiography was made at baseline, 15 and 30 days later. The defects were induced in the form of one osseous wall defects of 10 mm height, 4 mm depth between the 1st and the 2nd molars using a tapered fissure drill coupled to a high-speed motor. Statistical analysis was done using ANOVA.

RESULTS

(NanoHA-Graft+PRF+L) group significantly produced bone density higher than C, CL and NanoHA-G+PRF alone.

CONCLUSION

The combination of LLLT+PRF+NanoHA as a treatment modality induced the best results in bone formation in the bone defect more than LLLT alone or PRF+NanoHA alone.

Demineralized freeze-dried bone allograft with or without platelet-rich fibrin in the treatment of mandibular Degree II furcation defects: A clinical and cone beam computed tomography study

Background

Currently, there is no gold-standard regenerative material for the treatment of furcation defects. The use of bone grafts in combination with guided tissue regeneration membrane is a predictable treatment option but is expensive. Platelet concentrates are increasingly being used owing to their ease of use and cost-effectiveness.

Aims

The aim of this study is to evaluate the ability of platelet-rich fibrin (PRF) to augment the regenerative effects exerted by demineralized freeze-dried bone allograft (DFDBA) in the treatment of mandibular degree II furcation defects.

Materials and Methods

Twenty-eight defects in 14 patients with bilateral Degree II mandibular furcation defects were included in the study. The test group was treated with a combination of DFDBA and PRF, while in the control group DFDBA was used alone. Clinical parameters such as probing depth, relative vertical clinical attachment level, relative horizontal clinical attachment level (RHCAL), gingival margin level (GML), plaque index, and sulcus bleeding index were measured at baseline and 6 months. Radiographic parameters, such as vertical defect depth, horizontal defect depth and defect fill, were measured using cone beam computed tomography, taken at baseline and 6 months.

Statistical Analysis Used

The intragroup and intergroup comparisons were done using the paired t-test.

Results

The intergroup comparison of mean change in the parameters showed, statistically significant difference in RHCAL (<0.001) and GML (0.014), and no significant difference in other parameters.

Conclusions

Within the limitations of the present study, PRF seems to favor soft-tissue healing but has no additional benefit in bone regeneration when used in combination with DFDBA.

Combination Therapy for Reconstructive Periodontal Treatment in the Lower Anterior Area: Clinical Evaluation of a Case Series

Clinically, periodontal regeneration may be achieved by the application of barrier membranes, grafts, wound-healing modifiers, and their combinations. Combination therapy refers to the simultaneous application of various periodontal reconstructive treatment alternatives to obtain additive effects. This approach may lead to assemblage of different regenerative principles, such as conductivity and inductivity, space provision and wound stability, matrix development and cell differentiation. The application of autogenous connective tissue grafts during periodontal regenerative treatment with enamel matrix proteins derivative (EMD) has been previously reported. The present case series present a modified approach for treatment of severe periodontally involved lower incisors presenting with thin gingival biotype, gingival recession, minimal attached and keratinized gingiva width and muscle and/or frenum pull. In all cases a combination therapy consisting of a single buccal access flap, root conditioning, EMD application on the denuded root surfaces and a free connective tissue graft was performed. Clinical and radiographic outcomes were consistently satisfactory, leading to probing depth reduction, clinical attachment gain, minimal gingival recession, increased attached and keratinizing gingival width, elimination of frenum and/or muscle pull together with radiographic bone fill of the defects. It may be concluded that the present combination therapy for reconstructive periodontal treatment in the lower anterior area is a valuable alternative for indicated cases.

Human intrabony defect regeneration with micrografts containing dental pulp stem cells: A randomized controlled clinical trial

AIM

The goal of this study was to evaluate if dental pulp stem cells (DPSCs) delivered into intrabony defects in a collagen scaffold would enhance the clinical and radiographic parameters of periodontal regeneration.

MATERIALS AND METHODS

In this randomized controlled trial, 29 chronic periodontitis patients presenting one deep intrabony defect and requiring extraction of one vital tooth were consecutively enrolled. Defects were randomly assigned to test or control treatments which both consisted of the use of minimally invasive surgical technique. The dental pulp of the extracted tooth was mechanically dissociated to obtain micrografts rich in autologous DPSCs. Test sites (n = 15) were filled with micrografts seeded onto collagen sponge, whereas control sites (n = 14) with collagen sponge alone. Clinical and radiographic parameters were recorded at baseline, 6 and 12 months postoperatively.

RESULTS

Test sites exhibited significantly more probing depth (PD) reduction (4.9 mm versus 3.4 mm), clinical attachment level (CAL) gain (4.5 versus 2.9 mm) and bone defect fill (3.9 versus 1.6 mm) than controls. Moreover, residual PD < 5 mm (93% versus 50%) and CAL gain ≥4 mm (73% versus 29%) were significantly more frequent in the test group.

CONCLUSIONS

Application of DPSCs significantly improved clinical parameters of periodontal regeneration 1 year after treatment.

An overview of periodontal regenerative procedures for the general dental practitioner

The complete regeneration of the periodontal tissues following periodontal disease remains an unmet challenge, and has presented clinicians with a remarkably difficult clinical challenge to solve given the extensive research in this area and our current understanding of the biology of the periodontal tissues. In particular as clinicians we look for treatments that will improve the predictability of the procedure, improve the magnitude of the effect of treatment, and perhaps most importantly in the long term would extend the indications for treatment beyond the need for single enclosed bony defects to allow for suprabony regeneration, preferably with beneficial effects on the gingival soft tissues. A rapid development in both innovative methods and products for the correction of periodontal deficiencies have been reported during the last three decades. For example, guided tissue regeneration with or without the use of bone supplements has been a well-proven treatment modality for the reconstruction of bony defects prior to the tissue engineering era. Active biomaterials have been subsequently introduced to the periodontal community with supporting dental literature suggesting that certain factors should be taken into consideration when undertaking periodontal regenerative procedures. These factors as well as a number of other translational research issues will need to be addressed, and ultimately it is vital that we do not extrapolate results from pre-clinical and animal studies without conducting extensive randomized clinical trials to substantiate outcomes from these procedures. Whatever the outcomes, the pursuit of regeneration of the periodontal tissues remains a goal worth pursuing for our patients. The aim of the review, therefore is to update clinicians on the recent advances in both materials and techniques in periodontal regenerative procedures and to highlight the importance of both patient factors and the technical aspects of regenerative procedures.

Healing of two-wall intra-bony defects treated with a novel EMD-liquid-A pre-clinical study in monkeys

AIM

To investigate the effect of a novel enamel matrix derivative formulation (EMD-liquid or Osteogain) combined with an absorbable collagen sponge (ACS) on periodontal wound healing in intra-bony defects in monkeys.

MATERIALS AND METHODS

Chronic two-wall intra-bony defects were created at the distal aspect of eight teeth in three monkeys (Macaca fascicularis). The 24 defects were randomly assigned to one of the following treatments: (i) open flap debridement (OFD) + ACS alone, (ii) OFD + Emdogain + ACS (Emdogain/ACS), (iii) OFD + Osteogain + ACS (Osteogain/ACS) or (iv) OFD alone. At 4 months, the animals were euthanized for histologic evaluation.

RESULTS

Osteogain/ACS resulted in more consistent formation of cementum, periodontal ligament and bone with limited epithelial proliferation compared to OFD alone, Emdogain/ACS and OFD + ACS. Among the four treatment groups, the Osteogain/ACS group demonstrated the highest amount of regenerated tissues. However, complete periodontal regeneration was not observed in any of the defects in the four groups.

CONCLUSIONS

The present findings indicate that in two-wall intra-bony defects, reconstructive surgery with Osteogain/ACS appears to be a promising novel approach for facilitating periodontal wound healing/regeneration, thus warranting further clinical testing.

Guided tissue regeneration and platelet rich growth factor for the treatment of Grade II furcation defects: A randomized double-blinded clinical trial - A pilot study

Background

The treatment of furcation area defects remained as a challenging issue in periodontal treatments. Regeneration treatment of furcation defects is the most discussed periodontal treatment. Although not completely hopeless in prognosis, the presence of the furcation involvement significantly increases the chance of tooth loss. The current research was conductedeto compare theeadditive effect of combined guided tissue regeneration (GTR) and platelet-rich growth factor (PRGF) on the treatment of furcation bony defects.

Materials and Methods

A randomized, triple-blinded, split-mouth study was designed. It included patients with a moderate to severe chronic periodontitis with bilateral Grade II furcation involvement of first or second mandibular molars. Each side of mouth was randomly allocated for the treatment with either Bio-Gide American Society of Anesthesiologists GTR or a PRGF or PRGF by itself. Plaque index, gingival index, vertical clinical attachment level, vertical probing depth, recession depth (REC), horizontal probing depth, fornix to alveolar crest (FAC), fornix to base of defect (FBD), furcation vertical component and furcation horizontal component (FHC) were recorded. The current research was conducted to compare the additive effect of combined GTR and PRGF on treatment of furcation bony defects. Altman's nomogram, Kolmogorov-Smirnov test, Friedman test, general linear model, repeated measures, and paired t-test were used as statistical analysis in this research. P < 0.05 was considered statistically significant.

Results

Eight patients were finally enrolled for this study. Overly, general and specific clinical and furcation parameters were improved except REC that was deteriorated insignificantly and FAC improved not significantly. Intergroup comparison revealed better improvement of FHC in GTR/PRGF group (P = 0.02).

Conclusion

A significant improvement in the Grade II furcation defects treated with either GTR or PRGF/GTR was noticed. Further large-scale trials are needed to reveal differences of mentioned treatment in more details.

Treatment of Non-Contained Infrabony Defects With Enamel Matrix Derivative Alone or in Combination With Biphasic Calcium Phosphate Bone Graft: A 12-Month Randomized Controlled Clinical Trial

BACKGROUND

Use of enamel matrix derivative (EMD) when dealing with non-contained defects may be limited because EMD does not maintain a space itself. Use of combined therapy has been proposed, using a bone graft in combination with EMD to avoid collapse of the flap into the bony defect during healing time. Therefore, the aim of this study is to evaluate the clinical and radiologic healing response of non-contained infrabony defects after treatment with a combination of EMD and biphasic calcium phosphate (BC) or EMD alone.

METHODS

Fifty-two patients with at least one infrabony defect ≥3 mm in depth with a probing depth (PD) ≥6 mm were randomly treated with EMD/BC or EMD alone. Clinical and radiographic parameters were evaluated at baseline, 6, and 12 months after surgery. To standardize the procedure, an acrylic stent and millimeter radiographic grid were used. The primary outcome was the change in clinical attachment level (CAL).

RESULTS

Analysis of the data demonstrated a statistically significant difference from baseline within each group (P <0.05), with a difference in clinical and radiographic parameters at 6 and 12 months. After 1 year, mean PD reductions of 3.14 ± 1.95 mm (39.6%) in the EMD/BC group and 3.30 ± 1.89 mm (48.7%) in the EMD group were achieved. A mean CAL gain of 2.38 ± 2.17 mm (24.9%) in the EMD/BC group and 2.65 ± 2.18 mm (36.2%) in the EMD group were obtained. Reduction in the infrabony component was 2.71 ± 1.79 mm (57.9%) in the test group and 2.60 ± 2.03 mm (28.5%) in the control group. There were no statistically significant differences between treatment groups.

CONCLUSIONS

It was concluded that treatment of non-contained infrabony defects with EMD, with or without BC, resulted in statistically significantly better results after 12 months compared with baseline measurements. In contrast, the combined approach did not result in a statistically significant improvement.

Recent advancements in regenerative dentistry: A review

Although human mouth benefits from remarkable mechanical properties, it is very susceptible to traumatic damages, exposure to microbial attacks, and congenital maladies. Since the human dentition plays a crucial role in mastication, phonation and esthetics, finding promising and more efficient strategies to reestablish its functionality in the event of disruption has been important. Dating back to antiquity, conventional dentistry has been offering evacuation, restoration, and replacement of the diseased dental tissue. However, due to the limited ability and short lifespan of traditional restorative solutions, scientists have taken advantage of current advancements in medicine to create better solutions for the oral health field and have coined it "regenerative dentistry." This new field takes advantage of the recent innovations in stem cell research, cellular and molecular biology, tissue engineering, and materials science etc. In this review, the recently known resources and approaches used for regeneration of dental and oral tissues were evaluated using the databases of Scopus and Web of Science. Scientists have used a wide range of biomaterials and scaffolds (artificial and natural), genes (with viral and non-viral vectors), stem cells (isolated from deciduous teeth, dental pulp, periodontal ligament, adipose tissue, salivary glands, and dental follicle) and growth factors (used for stimulating cell differentiation) in order to apply tissue engineering approaches to dentistry. Although they have been successful in preclinical and clinical partial regeneration of dental tissues, whole-tooth engineering still seems to be far-fetched, unless certain shortcomings are addressed.

Minimally Invasive Treatment of Infrabony Periodontal Defects Using Dual-Wavelength Laser Therapy

Introduction. Surgical management of infrabony defects is an invasive procedure, frequently requiring the use of adjunctive material such as grafts or biologics, which is time-consuming and associated with expense and morbidity to the patient. Lasers in periodontal regeneration have been reported in the literature, with each wavelength having potential benefits through different laser-tissue interactions. The purpose of this case series was to assess the efficacy of a new dual-wavelength protocol in the management of infrabony defects. Materials and Methods. 32 defects (one in each patient) were treated using ultrasonic debridement, followed by flapless application of Erbium, Chromium:Yttrium, Scandium, Gallium, Garnet (Er,Cr:YSGG) laser (wavelength 2780 nm), and final application of diode laser (wavelength 940 nm). Pocket depths (PD) were measured after 6 months and repeat radiographs taken after one year. Results. The mean baseline PD was 8.8 mm (range 6–15 mm) and 6 months later was 2.4 mm (range 2–4 mm), with mean PD reduction being 6.4 ± 1.7 mm (range 3–12 mm). There was a significant gain in relative linear bone height (apical extent of bone), with mean percentage bone fill of 39.7 ± 41.2% and 53% of sites showing at least 40% infill of bone. Conclusion. The results compare favourably with traditional surgery and require further validation through randomised clinical controlled trials.

The Effect of an Er,Cr:YSGG Laser in the Management of Intrabony Defects Associated with Chronic Periodontitis Using Minimally Invasive Closed Flap Surgery. A Case Series

Aims: This is an extended case series of patients treated with an Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser as an adjunct to scaling for the management of intrabony defects. Materials & methods: 46 patients with 79 angular intrabony defects associated with pocket depths of >5mm, and a mean age of 53 ± 9 years presenting with chronic periodontitis were included in the analysis. All patients underwent a localized minimally invasive closed flap surgery utilizing Er,Cr:YSGG laser therapy. Final radiographs and pocket depths were compared to pretreatment measurements with a time period of 8 ± 3 months. Results: Treatment resulted in significant overall pocket depth reduction. The mean pre-op probing depth was 8.1 ± 1.9mm, reducing to 2.4 ± 0.9mm post-treatment. Bony infill of the defects was visible radiographically and there was an increase in overall radiographic coronal osseous height compared to a pre-treatment baseline. Radiographs of 15 of the defects were available for further measurements after >12 months, and showed in these sites there was a significant reduction in intrabony defect depth, but no change in suprabony bone height. 9 of the 15 sites showed 50% or more, bony infill of the intrabony defect. Conclusions: The results demonstrate that the utilization of an Er,Cr:YSGG laser in a closed flap approach with chronic periodontitis may be of significant clinical benefit. Further studies using this laser surgical protocol are required to test these observations in well-designed randomized controlled trials.

Gingival Mesenchymal Stem/Progenitor Cells: A Unique Tissue Engineering Gem

The human gingiva, characterized by its outstanding scarless wound healing properties, is a unique tissue and a pivotal component of the periodontal apparatus, investing and surrounding the teeth in their sockets in the alveolar bone. In the last years gingival mesenchymal stem/progenitor cells (G-MSCs), with promising regenerative and immunomodulatory properties, have been isolated and characterized from the gingival lamina propria. These cells, in contrast to other mesenchymal stem/progenitor cell sources, are abundant, readily accessible, and easily obtainable via minimally invasive cell isolation techniques. The present review summarizes the current scientific evidence on G-MSCs' isolation, their characterization, the investigated subpopulations, the generated induced pluripotent stem cells- (iPSC-) like G-MSCs, their regenerative properties, and current approaches for G-MSCs' delivery. The review further demonstrates their immunomodulatory properties, the transplantation preconditioning attempts via multiple biomolecules to enhance their attributes, and the experimental therapeutic applications conducted to treat multiple diseases in experimental animal models in vivo. G-MSCs show remarkable tissue reparative/regenerative potential, noteworthy immunomodulatory properties, and primary experimental therapeutic applications of G-MSCs are very promising, pointing at future biologically based therapeutic techniques, being potentially superior to conventional clinical treatment modalities.

Twenty years of enamel matrix derivative: the past, the present and the future

BACGROUND

On June 5th, 2015 at Europerio 8, a group of leading experts were gathered to discuss what has now been 20 years of documented evidence supporting the clinical use of enamel matrix derivative (EMD). Original experiments led by Lars Hammarström demonstrated that enamel matrix proteins could serve as key regenerative proteins capable of promoting periodontal regeneration including new cementum, with functionally oriented inserting new periodontal ligament fibres, and new alveolar bone formation. This pioneering work and vision by Lars Hammarström has paved the way to an enormous amount of publications related to its biological basis and clinical use. Twenty years later, it is clear that all these studies have greatly contributed to our understanding of how biologics can act as mediators for periodontal regeneration and have provided additional clinical means to support tissue regeneration of the periodontium.

AIMS

This review article aims to: (1) provide the biological background necessary to understand the rational for the use of EMD for periodontal regeneration, (2) present animal and human histological evidence of periodontal regeneration following EMD application, (3) provide clinically relevant indications for the use of EMD and (4) discuss future avenues of research including key early findings leading to the development of Osteogain, a new carrier system for EMD specifically developed with better protein adsorption to bone grafting materials.

Emerging regenerative approaches for periodontal reconstruction: a systematic review from the AAP Regeneration Workshop

More than 30 years have passed since the first successful application of regenerative therapy for treatment of periodontal diseases. Despite being feasible, periodontal regeneration still faces numerous challenges, and complete restoration of structure and function of the diseased periodontium is often considered an unpredictable task. This review highlights developing basic science and technologies for potential application to achieve reconstruction of the periodontium. A comprehensive search of the electronic bibliographic database PubMed was conducted to identify different emerging therapeutic approaches reported to influence either biologic pathways and/or tissues involved in periodontal regeneration. Each citation was assessed based on its abstract, and the full text of potentially eligible reports was retrieved. Based on the review of the full papers, their suitability for inclusion in this report was determined. In principle, only reports from scientifically well-designed studies that presented preclinical in vivo (animal studies) or clinical (human studies) evidence for successful periodontal regeneration were included. Hence, in vitro studies, namely those conducted in laboratories without any live animals, were excluded. In case of especially recent and relevant reviews with a narrow focus on specific regenerative approaches, they were identified as such, and thereby the option of referring to them to summarize the status of a specific approach, in addition to or instead of listing each separately, was preserved. Admittedly, the presence of subjectivity in the selection of studies to include in this overview cannot be excluded. However, it is believed that the contemporary approaches described in this review collectively represent the current efforts that have reported preclinical or clinical methods to successfully enhance regeneration of the periodontium. Today's challenges facing periodontal regenerative therapy continue to stimulate important research and clinical development, which, in turn, shapes the current concept of periodontal tissue engineering. Emerging technologies--such as stem cell therapy, bone anabolic agents, genetic approaches, and nanomaterials--also offer unique opportunities to enhance the predictability of current regenerative surgical approaches and inspire development of novel treatment strategies.

Recombinant human bone morphogenetic protein-9 potently induces osteogenic differentiation of human periodontal ligament fibroblasts

To accomplish effective periodontal regeneration for periodontal defects, several regenerative methods using growth and differentiation factors, including bone morphogenetic proteins (BMPs), have been developed. Bone morphogenetic protein-9 exhibits the most potent osteogenic activity of this growth factor family. However, it is unclear whether exogenous BMP-9 can induce osteogenic differentiation in human periodontal ligament (PDL) fibroblasts. Here, we examined the effects of recombinant human (rh) BMP-9 on osteoblastic differentiation in human PDL fibroblasts in vitro, compared with rhBMP-2. Recombinant human BMP-9 potently induced alkaline phosphatase (ALP) activity, mineralization, and increased expression of runt-related transcription factor-2/core binding factor alpha 1 (RUNX2/CBFA1), osterix, inhibitor of DNA binding/differentiation-1 (ID1), osteopontin, and bone sialoprotein genes, compared with rhBMP-2. The levels of rhBMP-9-induced osterix and ALP mRNA were significantly reduced in activin receptor-like kinase-1 and -2 small interfering RNA (siRNA)-transfected human PDL fibroblasts. Recombinant human BMP-9-induced ALP activity was not inhibited by noggin, in contrast to rhBMP-2 induced ALP activity, which was. Phosphorylation of SMAD1/5/8 in human PDL fibroblasts was induced by addition of rhBMP-9. Recombinant human BMP-9-induced ALP activity was suppressed by SB203580, SP600125, and U0126, which are inhibitors of p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase 1/2 (ERK1/2), respectively. Our data suggest that rhBMP-9 is a potent inducer of the differentiation of human PDL fibroblasts into osteoblast-like cells and that this may be mediated by the SMAD and mitogen-activated protein kinase (p38, ERK1/2, and JNK) pathways.

Minimally Invasive Surgery Combined with Regenerative Biomaterials in Treating Intra-Bony Defects: A Meta-Analysis

Background

With the popularity of minimally invasive surgery (MIS) in periodontics, numerous publications have evaluated the benefits of MIS with or without various regenerative biomaterials in the treatment of periodontal intra-bony defects. However, it is unclear if it is necessary to use biomaterials in MIS. Thus, we conducted a meta-analysis of randomized clinical trials in patients with intra-bony defects to compare the clinical outcomes of MIS with regenerative biomaterials for MIS alone.

Methods

The authors retrieved English publications on relevant studies from Cochrane CENTRAL, PubMed, Medline, Embase, Clinical Evidence, and ClinicalTrails.gov (up to June 30, 2015). The main clinical outcomes were the reduction of probing pocket depths (PPDs), gain of clinical attachment level (CAL), recession of gingival margin (REC) and radiographic bone fill. Review Manager 5.2 (Cochrane Collaboration, Oxford, England) was used to calculate the heterogeneity and mean differences of the main clinical outcomes.

Results

In total, 464 studies in the literature were identified but only four were ultimately feasible. The results showed no significant difference regarding CAL gain (P = 0.32) and PPD reduction (P = 0.40) as well as REC increase (P = 0.81) and radiographic bone fill (P = 0.64) between the MIS plus biomaterials group and the MIS alone group.

Conclusions

The meta-analysis suggested no significant difference in treatment of intra-bony defects between the MIS plus biomaterials group and the MIS alone group, indicating that it is important to take costs and benefits into consideration when a decision is made about a therapeutic approach. There needs to be an in-depth exploration of the induction of intrinsic tissue healing of MIS without biomaterials to achieve optimal outcomes.

Recombinant Human Bone Morphogenetic Protein 9 (rhBMP9) Induced Osteoblastic Behavior on a Collagen Membrane Compared With rhBMP2

BACKGROUND

Bone morphogenetic protein 9 (BMP9) has previously been characterized as one of the most osteogenic growth factors of the BMP family. To the best of the authors' knowledge, previous experiments have only used adenovirus transfection (gene therapy). With the recent development of recombinant human BMP9 (rhBMP9), the present study investigates the osteopromotive potential of BMP9 versus rhBMP2 when loaded onto collagen membranes.

METHODS

ST2 stromal bone marrow cells were seeded onto: 1) control; 2) low-dose rhBMP2 (10 ng/mL); 3) high-dose rhBMP2 (100 ng/mL); 4) low-dose rhBMP9 (10 ng/mL); and 5) high-dose rhBMP9 (100 ng/mL) porcine collagen membranes. The following parameters were compared among groups: 1) cell adhesion (at 8 hours); 2) cell proliferation (at 1, 3, and 5 days); 3) real-time polymerase chain reaction for genes encoding runt-related transcription factor 2; 4) alkaline phosphatase (ALP); 5) bone sialoprotein ([BSP] at 3 and 14 days); and 6) alizarin red staining (at 14 days).

RESULTS

rhBMP2 and rhBMP9 demonstrated little effect on cell attachment and proliferation; however, pronounced increases were observed in osteoblast differentiation. All groups significantly induced ALP messenger RNA (mRNA) levels at 3 days and BSP levels at 14 days; however, high-dose rhBMP9 showed significantly higher values compared with all other groups for ALP levels (five-fold increase at 3 days and two-fold increase at 14 days). Alizarin red staining further revealed both concentrations of rhBMP9 induced up to three-fold more staining compared with rhBMP2.

CONCLUSIONS

Results indicate that the combination of collagen membranes with rhBMP9 induced significantly higher ALP mRNA expression and alizarin red staining compared with rhBMP2. These findings suggest that rhBMP9 may be a suitable growth factor for future regenerative procedures in bone biology.

The Influence of Arginine on the Response of Enamel Matrix Derivative (EMD) Proteins to Thermal Stress: Towards Improving the Stability of EMD-Based Products

In a current procedure for periodontal tissue regeneration, enamel matrix derivative (EMD), which is the active component, is mixed with a propylene glycol alginate (PGA) gel carrier and applied directly to the periodontal defect. Exposure of EMD to physiological conditions then causes it to precipitate. However, environmental changes during manufacture and storage may result in modifications to the conformation of the EMD proteins, and eventually premature phase separation of the gel and a loss in therapeutic effectiveness. The present work relates to efforts to improve the stability of EMD-based formulations such as Emdogain^™ through the incorporation of arginine, a well-known protein stabilizer, but one that to our knowledge has not so far been considered for this purpose. Representative EMD-buffer solutions with and without arginine were analyzed by 3D-dynamic light scattering, UV-Vis spectroscopy, transmission electron microscopy and Fourier transform infrared spectroscopy at different acidic pH and temperatures, T, in order to simulate the effect of pH variations and thermal stress during manufacture and storage. The results provided evidence that arginine may indeed stabilize EMD against irreversible aggregation with respect to variations in pH and T under these conditions. Moreover, stopped-flow transmittance measurements indicated arginine addition not to suppress precipitation of EMD from either the buffers or the PGA gel carrier when the pH was raised to 7, a fundamental requirement for dental applications.