To assess the efficacy of socket plug technique using platelet rich fibrin with or without the use of bone substitute in alveolar ridge preservation: a prospective randomised controlled study

Using autogenous tooth graft for alveolar ridge preservation: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A meta-analysis of the efficacy of autogenous tooth graft (ATG) for alveolar ridge preservation is still lacking given that earlier articles did not present a quantified synthesis or have a control group in their evaluation of the performance of ATG in comparison with other available materials.

PURPOSE

The purpose of this systematic review and meta-analysis was to critically assess the existing literature on the efficacy of ATG for alveolar ridge preservation.

MATERIAL AND METHODS

The Scopus, MEDLINE/PubMed, and Cochrane Library databases were searched, with additional searches in the nonpeer-reviewed literature, screening for clinical studies that compared ATG with empty sockets or other materials and reported results on alveolar ridge dimensional changes or bone formation. A meta-analysis was performed using the standardized mean difference for the comparisons of alveolar ridge changes and the mean difference for bone formation. The random-effect model was implemented in all analyses.

RESULTS

Fourteen studies were included. Regarding ridge width, a significant difference was noted between the ATG and empty sockets (SMD=1.60, 95% CI=0.53 to 2.66, P=.003). No significant difference was recorded compared with other grafts. As for ridge height, the results revealed no significant difference between the ATG and empty sockets and other grafts (P>.05). Moreover, no difference in bone formation between the ATG and empty sockets was seen (P>.05), while ATG demonstrated a higher percentage of bone formation than other grafts (MD=12.01, 95% CI=3.86 to 20.15, P=.004). Based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system, the evidence on ridge width and bone formation was moderate, while the ridge height outcome was of a low level.

CONCLUSIONS

Most of the studies included had a small sample size with potential risk of bias. Within these limitations, ATG could be an alternative for alveolar ridge preservation, as it demonstrates the ability to preserve volume and regenerate new bone in the grafted area.

Development of Semi-Automated Image-Based Analysis Tool for CBCT Evaluation of Alveolar Ridge Changes After Tooth Extraction

Following tooth extraction, the bone structure is prone to atrophic changes. Alveolar ridge resorption can compromise subsequent implant treatment not only at the extraction site itself but also by affecting the bone support of adjacent teeth. Various techniques, including the use of bone graft materials or autologous blood concentrates for ridge or socket preservation, aim to counteract this process. The efficacy of such methods can be evaluated non-invasively through radiological analysis of the treated region. However, existing radiological evaluation methods often focus only on isolated areas of the extraction socket, limiting their accuracy in assessing overall bone regeneration. This study introduces a novel, non-invasive, and semi-automated image-based analysis method that enables a more comprehensive evaluation of bone preservation using CBCT data. Developed with the open-source software "Fiji" (v2.15.0; based on ImageJ), the approach assesses bone changes at multiple horizontal and vertical positions, creating a near three-dimensional representation of the resorptive process. By analyzing the entire region around the extraction socket rather than selected regions, this method provides a more precise and reproducible assessment of alveolar ridge preservation. Although the approach requires some processing time and focuses exclusively on radiological evaluation, it offers greater accuracy than conventional methods. Its standardized and objective nature makes it a valuable tool for clinical research, facilitating more reliable comparisons of different socket preservation strategies.

Introduction of a Semi-Quantitative Image-Based Analysis Tool for CBCT-Based Evaluation of Bone Regeneration in Tooth Extraction Sockets

After tooth extraction, resorptive changes in extraction sockets and the adjacent alveolar ridge can affect subsequent tooth replacement and implantation. Several surgical concepts, including the application of autologous blood concentrate platelet-rich fibrin (PRF), aim to reduce these changes. While PRF's wound-healing and pain-relieving effects are well-documented, its impact on bone regeneration is less clear due to varying PRF protocols and measurement methods for bone regeneration. This study aimed to develop a precise, easy-to-use non-invasive radiological evaluation method that examines the entire extraction socket to assess bone regeneration using CBCT data from clinical trials. The method, based on the freely available Image J-based software "Fiji", proved to be precise, reproducible, and transferable. As limitation remains the time requirement and its exclusive focus on radiological bone regeneration. Nevertheless, the method presented here is more precise than the ones currently described in the literature, as it evaluates the entire socket rather than partial areas. The application of the novel method to measure mineralized socket volume and radiological bone density of newly formed bone in a randomized, controlled clinical trial assessing solid PRF for socket preservation in premolar and molar sockets showed only slight, statistically non-significant trends toward better regeneration in the PRF group compared to natural healing.

How to explain the beneficial effects of leukocyte- and platelet-rich fibrin

The survival of an organism relies on its ability to repair the damage caused by trauma, toxic agents, and inflammation. This process involving cell proliferation and differentiation is driven by several growth factors and is critically dependent on the organization of the extracellular matrix. Since autologous platelet concentrates (APCs) are fibrin matrices in which cells, growth factors, and cytokines are trapped and delivered over time, they are able to influence that response at different levels. The present review thoroughly describes the molecular components present in one of these APCs, leukocyte- and platelet-rich fibrin (L-PRF), and summarizes the level of evidence regarding the influence of L-PRF on anti-inflammatory reactions, analgesia, hemostasis, antimicrobial capacity, and its biological mechanisms on bone/soft tissue regeneration.

A systematic review and meta-analysis on the use of regenerative graft materials for socket preservation in randomized clinical trials

OBJECTIVE

To evaluate if regenerative materials with/without scaffold deployed in dental socket preservation led to reduced radiographic height and width bone resorption.

STUDY DESIGN

English-written human studies from January 2010 to December 2023 were selected from PubMed, EMBASE, MEDLINE, Cochrane CENTRAL, Google Scholar and manually searched journals. Six meta-analyses were conducted, addressing treatments with all blood-derived growth factor preparations as well as L-platelet-rich fibrin (L-PRF) separately, and recombinant human BMP-2 (rhBMP-2). An unpaired t-test on L-PRF and rhBMP-2 determined the clinically best preservation treatment. Cochrane risk of bias in all studies was analyzed.

RESULTS

Twenty-nine articles (1068 participants) were included. Meta-analyses on blood-derived preparations demonstrated nonsignificant alveolar width, but significant (p = .001) height preservation. L-PRF vs. natural healing demonstrated nonsignificant changes in both dimensions. RhBMP-2 caused highly significant reduced horizontal (p = .01) and vertical (p < .0008) bone resorptions. When comparing mean resorption rates, significant benefits of rhBMP-2 over L-PRF were observed for width but not height preservation (p < .0001 and p = .057, respectively). Six studies recorded low, 8 moderate, and 15 high net risks.

CONCLUSIONS

Regenerative materials appear beneficial for radiographic bone width and height preservation after tooth extraction. Although rhBMP-2 performed better in alveolar width preservation, L-PRF can be an autologous and cost-effective alternative.

Comparison of Histological, Clinical, and Radiographic Outcomes of Postextraction Ridge Preservation by Allogenic Bone Grafting With and Without Injectable Platelet-Rich Fibrin: A Double-Blinded Randomized Controlled Clinical Trial

Objectives: This randomized controlled clinical trial compared the histological, clinical, and radiographic outcomes of postextraction ridge preservation by allogenic bone grafting with and without injectable platelet-rich fibrin (I-PRF). Materials and Methods: Twenty single-rooted maxillary and mandibular teeth to be extracted and replaced by dental implants were randomly divided into two groups (n = 10). Cone-beam computed tomography (CBCT) scans were obtained preoperatively to assess bone dimensions and ridge width. The teeth were then extracted, and tooth socket preservation was performed with allograft and collagen type 1 in the control group and allograft, collagen type 1, and I-PRF in the intervention group. CBCT scans were obtained again 3 months after the first stage of surgery, and the second stage of surgery was performed for implant placement, ridge width measurement, and obtaining a biopsy sample. Radiographic bone width, clinical bone width, and radiographic bone height were measured. A histomorphometric method was applied to quantify residual graft material, new bone formation, and nonmineralized tissues. The data were analyzed with Student's t-test and Mann-Whitney U test (α = 0.05). Results: The intervention group showed a significantly smaller reduction in radiographic bone width (P=0.038) and clinical bone width (P=0.033), reduction in radiographic bone height (P=0.213) was not significant. A significantly lower percentage of residual graft particles (P=0.021) and a significantly higher mean percentage of newly formed bone (P=0.038) than the control group. However, the difference in the percentage of nonmineralized tissue (P=0.208) was not significant. Conclusion: Despite the optimal outcome of ridge preservation in both groups, the application of allograft plus I-PRF yielded superior histological, clinical, and radiographic results compared with allograft alone, and this difference was significant in most variables.

Efficacy of autologous platelet concentrate products for alveolar preservation: A meta-analysis

PURPOSE

The purpose of the study was to systematically evaluate the efficacy of autologous platelet concentrate products in the preservation of the alveolar ridge after tooth extraction through meta-analysis and provide a theoretical basis for the clinical application of autologous platelet concentrates to reduce alveolar bone resorption.

METHODS

This study conducted a meta-analysis of clinical trials between 2013 and 2023, focusing on autologous platelet concentrate products (e.g., PRP, PRF, CGF, and PRCF) used for alveolar ridge preservation after tooth extraction. The analysis included 122 articles and 371 extraction sockets. All statistical analyses were performed using Review Manager version 5.4.

RESULTS

Results indicate that these platelet concentrates effectively reduced changes in horizontal width 1 mm below the alveolar crest and vertical socket height. They also promoted a higher percentage of new bone formation in extraction sockets compared with control groups. However, they did not significantly prevent horizontal bone resorption at 3 and 5 mm below the alveolar crest.

CONCLUSION

In conclusion, autologous platelet concentrates are useful for alveolar ridge preservation, but larger clinical studies are needed to confirm these findings due to the relatively small sample size in this study.

Performance of a multiphase bioactive socket plug with a barrier function for alveolar ridge preservation

The natural healing process of extraction socket and traditional socket plug material could not prevent buccal bone wall resorption and down growth of epithelium from the socket orifice. A multiphase bioactive socket plug (BP) is designed to overcome the natural healing process by maintaining the three-dimensional (3D) volume of extraction sockets, particularly in sockets with wall defects, and later provide sufficient alveolar bone volume for implant placement. The study aimed to fabricate and evaluate the physical, chemical, and biological performance of BPin vitro. The BP was fabricated through freeze-drying and layer-by-layer assembly, comprised of a base serving as a scaffold, a central portion for promoting bone regeneration, an upper buccal portion for maintaining alveolar socket dimension with a covering collagen membrane (Memb) on the top and upper buccal surface to prevent soft tissue infiltration. The BP as the experimental group and a pure collagen plug (CP) as the control group were investigated and compared. Radiograph, scanning electron microscopy, and energy-dispersive spectroscopy mapping confirmed that the four-part BP was successfully assembled and fabricated. Swelling rate analysis indicated that BP, CP, and Memb reached swelling equilibrium within 1 hour. BP exhibited a high remaining weight percentage in collagenase solution (68.81 ± 2.21% on day 90) and sustained calcium ion release, reaching the maximum 0.13 ± 0.04 mmol l-1on day 14. In biological assays, BP exhibited excellent cell proliferation (The OD value increased from 0.02 on day 1 to 0.23 on day 21.). The BP group exhibited higher alkaline phosphatase activity and osteocalcin content than the CP group within 21 days. Memb and BP exhibited outstanding barrier function, as evidenced by Hematoxylin and eosin staining. In summary, the multiphase bioactive socket plug represents a promising scaffold for alveolar ridge preservation application.

Efficacy of Platelet-Rich Fibrin in Preserving Alveolar Ridge Volume and Reducing Postoperative Pain in Site Preservation of Post-Extracted Sockets

Background and Objectives: In socket preservation, the goal is to minimize bone resorption after tooth extraction to maintain the volume and contour of the alveolar ridge. The use of PRF in post extraction sites may reduce ridge resorption by encouraging the growth of new bone and acting as a scaffold for tissue. In addition, PRF may enhance healing and minimize postoperative pain. The aim of this study was to evaluate the effectiveness of platelet-rich fibrin (PRF) in maintaining the ridges' dimensions at the extraction site, in the maxilla and mandible, as well as its impact on post-extraction discomfort. Methods: The study was conducted on 60 patients presenting for extraction of posterior teeth and was randomly divided into three groups: group I PRF (n = 20), group II PRF + collagen (n = 20), and group III control (n = 20). Sockets were filled with PRF (group I) and PRF + collagen (group II). At baseline and follow-up after 3 months, CBCT was used to assess the bone dimensions. The postoperative pain evaluations were performed at 24 h, 3 days, and 7 days after the tooth extraction. The pain rate was evaluated using a numerical rating scale from the British Pain Society. Results: The study examined the effects of platelet-rich fibrin (PRF) and PRF combined with collagen on the height and width of the ridges, as well as the pain experienced by the patients following alveolar ridge preservation surgery. ANOVA and t-tests were used to evaluate and compare the ridge dimensions. Comparing the results to the control group, there were no significant differences in the height or width of the ridges. However, both the PRF and PRF + Collaplug® treatments effectively reduced the short-term postoperative pain. Conclusions: The study findings suggest that platelet-rich fibrin (PRF) and PRF combined with collagen do not exert significant effects on ridge width and height compared to the standard treatment following alveolar ridge preservation. However, it is noteworthy that both the PRF and PRF + collagen treatments demonstrated efficacy in reducing postoperative pain in the short term, offering a potential advantage over standard treatment protocols.

Exploring the potential of calcium-based biomaterials for bone regeneration in dentistry: a systematic review

INTRODUCTION

Regenerative medicine emerged as a promising strategy for addressing bone defects, with several bone grafts currently being used, including autografts, allografts, xenografts and alloplasts. Calcium-based biomaterials (CaXs), a well-known class of synthetic materials, have demonstrated good biological properties and are being investigated for their potential to facilitate bone regeneration. This systematic review evaluates the current clinical applications of CaXs in dentistry for bone regeneration.

EVIDENCE ACQUISITION

A comprehensive search was conducted to collect information about CaXs and their applications in the dental field over the last ten years. The search was limited to relevant articles published in peer-reviewed journals.

EVIDENCE SYNTHESIS

A total of 72 articles were included in this scoping review, with eight studies related to periodontology, 63 in implantology and three in maxillofacial surgery respectively. The findings suggest that CaXs hold promise as an alternative intervention for minor bone regeneration in dentistry.

CONCLUSIONS

Calcium-based biomaterials have shown potential as a viable option for bone regeneration in dentistry. Further research is warranted to fully understand their efficacy and safety in larger bone defects. CaXs represent an exciting avenue for researchers and clinicians to explore in their ongoing efforts to advance regenerative medicine.

A new hydroxyapatite-alginate-gelatin biocomposite favor bone regeneration in a critical-sized calvarial defect model

This study aimed to evaluate the osteogenic potential of hydroxyapatite (HA), Alginate (Alg), and Gelatine (Gel) composite in a critical-size defect model in rats. Twenty-four male rats were divided into three groups: a negative control with no treatment (Control group), a positive control treated with deproteinized bovine bone mineral (DBBM group), and the experimental group treated with the new HA-Alg-Gel composite (HA-Alg-Gel group). A critical size defect (8.5mm) was made in the rat's calvaria, and the bone formation was evaluated by in vivo microcomputed tomography analysis (µCT) after 1, 15, 45, and 90 days. After 90 days, the animals were euthanized and histological and histomorphometric analyses were performed. A higher proportion of mineralized tissue/biomaterial was observed in the DBBM group when compared to the HA-Alg-Gel and Control groups in the µCT analysis during all analysis periods. However, no differences were observed in the mineralized tissue/biomaterial proportion observed on day 1 (immediate postoperative) in comparison to later periods of analysis in all groups. In the histomorphometric analysis, the HA-Alg-Gel and Control groups showed higher bone formation than the DBBM group. Moreover, in histological analysis, five samples of the HA-Alg-Gal group exhibited formed bone spicules adjacent to the graft granules against only two of eight samples in the DBBM group. Both graft materials ensured the maintenance of defect bone thickness, while a tissue thickness reduction was observed in the control group. In conclusion, this study demonstrated the osteoconductive potential of HA-Alg-Gel bone graft by supporting new bone formation around its particles.

Evaluation of Alveolar Ridge Dimensions by Socket Preservation Therapy Using a Bone Graft and Platelet-Rich Fibrin: A Randomized Controlled Trial

BACKGROUND

Following the loss of a tooth, the new edentulous area of the ridge will undergo several adaptive modifications due to changes in function within and surrounding the socket. This bone resorption explains the need for socket preservation techniques in areas of esthetic concerns and functional demands. Demineralized freeze-dried bone allograft (DFDBA) possesses greater osteoinductive potential due to the exposure of bone morphogenetic protein (BMP-3​​​​​​)​and collagen fibrils and can be used efficiently in socket preservation techniques. DFDBA yields better results when combined with an autologous platelet concentrate, such as platelet-rich fibrin. Therefore, we formulated this randomized controlled clinical trial to assess the clinical and radiovisiographical outcomes of platelet-rich fibrin (PRF) and DFDBAs for extraction socket preservation in humans at different time intervals.

MATERIALS AND METHODS

This was a randomized controlled trial with 100 people as study subjects, and they were randomly divided into two groups: the test group (DFDBA and PRF placed in the extraction socket) and the control group (natural healing of the extraction socket). Clinical and radiographic evaluation using radiovisiography (RVG) was done at baseline, three-month, and six-month intervals. Cone-beam computed tomography (CBCT) was used at six months to determine the bone density in the test and control groups.

RESULTS

When compared from baseline to six months, the percentage change in clinical and RVG measurements for the test group was 15.96% (11.9064 mm) and 16.77% (12.1840 mm), respectively, whereas for the control group, it was 46.09% (14.0396 mm) and 47.61% (14.5716 mm), thus indicating lesser bone resorption in the test group as opposed to the control group. CBCT values also showed greater bone density for the test group (682.3120 HU) than the control group (503.8336 HU).

CONCLUSION

This study demonstrates the advantages of DFDBA bone graft with PRF compared to natural healing in achieving socket preservation by maintaining the marginal and buccolingual bone levels.

Do autologous platelet concentrates (APCs) have a role in intra-oral bone regeneration? A critical review of clinical guidelines on decision-making process

In the past decades, personalized regenerative medicine has gained increased attention. Autologous platelet concentrates (APCs) such as PRP, PRGF, and L-PRF, all serving as a source of a large variety of cells and growth factors that participate in hard and soft tissue healing and regeneration, could play a significant role in regenerative periodontal procedures. This narrative review evaluated the relative impact of APCs in alveolar ridge preservation, sinus floor augmentation, and the regeneration of bony craters around teeth, both as a single substitute or in combination with a xenograft. L-PRF has a significant beneficial effect on alveolar ridge preservation (bone quality). The data for PRGF are less convincing, and PRP is controversial. L-PRF can successfully be used as a single substitute during transcrestal (≥3.5 mm bone gain) as well as 1-stage lateral window sinus floor elevation (>5 mm bone gain). For PRGF and especially PRP the data are very scarce. In the treatment of bony craters around teeth, during open flap debridement, L-PRF as a single substitute showed significant adjunctive benefits (e.g., >PPD reduction, >CAL gain, >crater depth reduction). The data for PRP and PRGF were non-conclusive. Adding PRP or L-PRF to a xenograft during OFD resulted in additional improvements (>PPD reduction, >CAL gain, >bone fill), for PRGF no data were found. Autologous platelet concentrates demonstrated to enhance bone and soft tissue healing in periodontal regenerative procedures. The data for L-PRF were most convincing. L-PRF also has the advantage of a greater simplicity of production, and its 100% autologous character.

Alveolar ridge preservation in post-extraction sockets using concentrated growth factors: a split-mouth, randomized, controlled clinical trial

Aim

The aim of this clinical trial was to assess the impact of autologous concentrated growth factor (CGF) as a socket-filling material and its ridge preservation properties following the lower third molar extraction.

Materials and methods

A total of 60 sides of 30 participants who had completely symmetrical bilateral impacted lower third molars were enrolled. The primary outcome variables of the study were bone height and width, bone density, and socket surface area in the coronal section. Cone beam computed tomography images were obtained immediately after surgery and three months after surgery as a temporal measure. Follow-up data were compared to the baseline using paired and unpaired t-tests.

Results

CGF sites had higher values in height and width when compared to control sites (Buccal wall 32.9 ± 3.5 vs 29.4 ± 4.3 mm, Lingual wall 25.4 ± 3.5 vs 23.1 ± 4 mm, and Alveolar bone width 21.07 ± 1.55vs19.53 ± 1.90 mm, respectively). Bone density showed significantly higher values in CGF sites than in control sites (Coronal half 200 ± 127.3 vs -84.1 ± 121.3 and Apical half 406.5 ± 103 vs 64.2 ± 158.6, respectively). There was a significant difference between both sites in the reduction of the periodontal pockets.

Conclusion

CGF application following surgical extraction provides an easy, low-cost, and efficient option for alveolar ridge preservation. Thus, the use of CGF by dentists during dental extractions may be encouraged, particularly when alveolar ridge preservation is required.

Clinical trial registration

TCTR identification, TCTR20221028003.

Does the Choice of Preparation Protocol for Platelet-Rich Fibrin Have Consequences for Healing and Alveolar Ridge Preservation After Tooth Extraction? A Meta-Analysis

PURPOSE

Multiple preparation protocols for platelet-rich fibrin (PRF) are in use today, and clinical results are often heterogeneous. This study analyzes the impact of the chosen PRF preparation protocol on 1) wound healing and 2) alveolar ridge preservation.

METHODS

For this systematic review and meta-analysis, eligible studies were identified in PubMed and Cochrane databases. Included were randomized controlled and controlled clinical trials with healthy patients treated with PRF after atraumatic tooth extraction compared to untreated socket(s), reporting at least one of the following outcome variables: pain, swelling, soft tissue healing, alveolar osteitis risk, horizontal and vertical bone loss, socket fill, and new bone formation. Main predictor variable was relative centrifugal force (RCF) comparing high RCF (high PRF), intermediate RCF (standard [S-PRF]), low RCF (advanced PRF), and various RCF settings (concentrated growth factor preparation [CGF]). The type of centrifugation tubes (silica-coated plastic and glass) was a secondary predictor. Weighted or standardized mean differences, risk ratio and corresponding 95% confidence intervals were calculated.

RESULTS

Forty studies published between 2012 and 2022 were selected. The pooled effects of all outcomes were significant against untreated sockets. Within the subgroups high PRF or advanced PRF had the lowest efficacy for many outcome parameters. Pain reduction (in visual analog scale units) was highest for S-PRF (-1.18 [-1.48, -0.88], P < .00001) and CGF (-1.03 [-1.16, -0.90], P < .001). The risk ratio of alveolar osteitis (0.09 [0.01, 0.69], P < .02) and soft tissue healing (standardized mean difference = 2.55 [2.06, 3.03], P < .001) were best for CGF. No subgroup differences were found for bone-related outcomes. No meaningful analysis of the tube material effect was possible.

CONCLUSION

This study confirms that PRF is associated with reduced postoperative complications but indicates that preparation protocol influences clinical outcomes. S-PRF and CGF protocols appear to be superior for several outcome parameters.

Can Our Blood Help Ensure Antimicrobial and Anti-Inflammatory Properties in Oral and Maxillofacial Surgery?

In recent decades, the potential of PRF has been extensively studied. The number of studies about PRF has increased three times since the year 2012, but the full spectrum of its fundamental properties, such as antimicrobial and anti-inflammatory activity, is not clearly described. In oral and maxillofacial surgery, PRF is described in alveolar ridge preservation, orthognathic surgery, cleft lip and palate surgery, maxillary sinus augmentation, and dental implant placement as demonstrating favorable results and its clinical advantages. The structural complexity, inhomogeneous nature, and clotting ability of PRF make its antimicrobial effect evaluation complicated. Nevertheless, most of the used antimicrobial testing methods are based on antibacterial agent diffusion ability in culture media. Because the oral and maxillofacial region is the most frequent area of PRF application, its antimicrobial activity evaluation also prevails in the oral microbiome. PRF's biological potential is highly dependent on the specific preparation protocol and methodology used; it should be carefully prepared and kept under proper conditions to keep cellular content alive. PRF's influence on living cells demonstrates a stimulating effect on bone regeneration, and an angiogenetic effect, and it provides anti-inflammatory activity. According to analyzed studies, PRF demonstrated success in oral and maxillofacial surgery in various methods of application. Antibacterial and anti-inflammatory properties were proven by antibacterial activity against different bacterial species, sustained growth factor, sustained release, and cell activity on the material application. Accurately and correctly prepared PRF can ensure antibacterial and anti-inflammatory properties, and it can be a beneficial clinical tool in oral and maxillofacial surgery.

GARP Regulates the Immune Capacity of a Human Autologous Platelet Concentrate

Autologous platelet concentrates, like liquid platelet rich fibrin (iPRF), optimize wound healing; however, the underlying immunological mechanisms are poorly understood. Platelets, the main cellular component of iPRF, highly express the protein, Glycoprotein A repetitions predominant (GARP), on their surfaces. GARP plays a crucial role in maintaining peripheral tolerance, but its influence on the immune capacity of iPRF remains unclear. This study analyzed the interaction of iPRF with immune cells implicated in the wound healing process (human monocyte derived macrophages and CD4⁺ T cells) and evaluated the distinct influence of GARP on these mechanisms in vitro. GARP was determined to be expressed on the surface of platelets and to exist as a soluble factor in iPRF. Platelets derived from iPRF and iPRF itself induced a regulatory phenotype in CD4⁺ T cells, shown by increased expression of Foxp3 and GARP as well as decreased production of IL-2 and IFN-γ. Application of an anti-GARP antibody reversed these effects. Additionally, iPRF polarized macrophages to a "M0/M2-like" phenotype in a GARP independent manner. Altogether, this study demonstrated for the first time that the immune capacity of iPRF is mediated in part by GARP and its ability to induce regulatory CD4⁺ T cells.

Efficacy of biologics for alveolar ridge preservation/reconstruction and implant site development: An American Academy of Periodontology best evidence systematic review

BACKGROUND

The use of biologics may be indicated for alveolar ridge preservation (ARP) and reconstruction (ARR), and implant site development (ISD). The present systematic review aimed to analyze the effect of autologous blood-derived products (ABPs), enamel matrix derivative (EMD), recombinant human platelet-derived growth factor-BB (rhPDGF-BB), and recombinant human bone morphogenetic protein-2 (rhBMP-2), on the outcomes of ARP/ARR and ISD therapy (i.e., alveolar ridge augmentation [ARA] and maxillary sinus floor augmentation [MSFA]).

METHODS

An electronic search for eligible articles published from January 2000 to October 2021 was conducted. Randomized clinical trials evaluating the efficacy of ABPs, EMD, rhBMP-2, and rhPDGF-BB for ARP/ARR and ISD were included according to pre-established eligibility criteria. Data on linear and volumetric dimensional changes, histomorphometric findings, and a variety of secondary outcomes (i.e., clinical, implant-related, digital imaging, safety, and patient-reported outcome measures [PROMs]) were extracted and critically analyzed. Risk of bias assessment of the selected investigations was also conducted.

RESULTS

A total of 39 articles were included and analyzed qualitatively. Due to the high level of heterogeneity across studies, quantitative analyses were not feasible. Most studies in the topic of ARP/ARR revealed that the use of biologics rendered similar results compared with conventional protocols. However, when juxtaposed to unassisted healing or socket filling using collagen sponges, the application of biologics did contribute to attenuate post-extraction alveolar ridge atrophy in most investigations. Additionally, histomorphometric outcomes were positively influenced by the application of biologics. The use of biologics in ARA interventions did not yield superior clinical or radiographic outcomes compared with control therapies. Nevertheless, ABPs enhanced new bone formation and reduced the likelihood of early wound dehiscence. The use of biologics in MSFA interventions did not translate into superior clinical or radiographic outcomes. It was observed, though, that the use of some biologics may promote bone formation during earlier stages of healing. Only four clinical investigations evaluated PROMs and reported a modest beneficial impact of the use of biologics on pain and swelling. No severe adverse events in association with the use of the biologics evaluated in this systematic review were noted.

CONCLUSIONS

Outcomes of therapy after post-extraction ARP/ARR and ARA in edentulous ridges were comparable among different therapeutic modalities evaluated in this systematic review. Nevertheless, the use of biologics (i.e., PRF, EMD, rhPDGF-BB, and rhBMP-2) in combination with a bone graft material generally results into superior histomorphometric outcomes and faster wound healing compared with control groups.

Solid PRF Serves as Basis for Guided Open Wound Healing of the Ridge after Tooth Extraction by Accelerating the Wound Healing Time Course-A Prospective Parallel Arm Randomized Controlled Single Blind Trial

Systematic evaluations regarding the influence of PRF in ridge sealing are still lacking. To the best of our knowledge, this is the first systemic randomized, controlled, clinical approach dealing with the potential of a systematic applied solid PRF on soft tissue socket healing of molar and premolar extraction sockets with evaluation for up to 90 days. Qualitative and quantitative image analysis showed that PRF contributed to a significantly faster ridge sealing, within the period of 7-10 days in both tooth types. This led to a visibly less contraction at the PRF-treated group sites at day 90. Patients' pain perception demonstrated no statistic significance between both groups (PRF vs. natural healing), but the patients in PRF group seemed to have had less pain throughout the observational period. It becomes evident that PRF is able to serve as a promotor of the secondary wound healing cascade. The guiding capacity of PRF accelerating the process of open ridge healing makes it possible to act as a natural growth factor drug delivery system, providing a more predictable guided open wound healing of the ridge with less contraction of the soft tissue, the latter being a key factor for the subsequent successful dental implantation and oral rehabilitation.

Regenerative Potential of Platelet Rich Fibrin (PRF) in Socket Preservation in Comparison with Conventional Treatment Modalities: A Systematic Review and Meta-Analysis

BACKGROUND

Platelet rich fibrin (PRF) has shown great potential in osteogenesis; however, some studies still question utilizing it as a grafting material. Thus, the aim of this review is to evaluate the effect of PRF when used in socket and ridge preservation procedures.

METHODS

Electronic searches through MEDLINE, EMBASE, and Cochrane, Science Citation Index Expanded databases and manual searches of unpublished data, academic theses, and journals were conducted up until July 2021. The outcomes were to assess the ability of PRF as a graft material to preserve bone width, height, and density after tooth extraction.

RESULTS

Twelve studies were included in the review, using PRF showed significant results in all three outcomes when compared to no grafting at all, however when compared to other commonly used grafting materials it showed a lesser effect. On the other hand, most studies included reported mixing PRF with a graft material showed the best result. The meta-analysis also revealed the significant results in using PRF on the three outcomes.

CONCLUSION

The meta-analysis of the studies included proved the beneficial effect of PRF in socket preservation surgeries alone or in combination with other graft materials, but further individual multi-centre randomized controlled studies with appropriate sample size are still needed to further confirm our findings.

Efficacy of platelet-rich fibrin in promoting the healing of extraction sockets: a systematic review

PURPOSE

To address the focused question: in patients with freshly extracted teeth, what is the efficacy of platelet-rich fibrin (PRF) in the prevention of pain and the regeneration of soft tissue and bone compared to the respective control without PRF treatment?

METHODS

After an electronic data search in PubMed database, the Web of Knowledge of Thomson Reuters and hand search in the relevant journals, a total of 20 randomized and/or controlled studies were included.

RESULTS

66.6% of the studies showed that PRF significantly reduced the postoperative pain, especially in the first 1-3 days after tooth extraction. Soft tissue healing was significantly improved in the group of PRF compared to the spontaneous wound healing after 1 week (75% of the evaluated studies). Dimensional bone loss was significantly lower in the PRF group compared to the spontaneous wound healing after 8-15 weeks but not after 6 months. Socket fill was in 85% of the studies significantly higher in the PRF group compared to the spontaneous wound healing.

CONCLUSIONS

Based on the analyzed studies, PRF is most effective in the early healing period of 2-3 months after tooth extraction. A longer healing period may not provide any benefits. The currently available data do not allow any statement regarding the long-term implant success in sockets treated with PRF or its combination with biomaterials. Due to the heterogeneity of the evaluated data no meta-analysis was performed.

Dimensional and histomorphometric evaluation of biomaterials used for alveolar ridge preservation: a systematic review and network meta-analysis

OBJECTIVES

This systematic review and network meta-analysis aimed to answer to the following questions: (a) In patients undergoing alveolar ridge preservation after tooth extraction, which grafting material best attenuates horizontal and vertical ridge resorption, as compared to spontaneous healing?, and (b) which material(s) promotes bone formation in the extraction socket?

MATERIALS AND METHODS

The MEDLINE, SCOPUS, CENTRAL, and EMBASE databases were screened in duplicate for RCTs up to March 2021. Two independent authors extracted the data and assessed the risk of bias of the included studies. Primary outcomes were ridge horizontal and vertical dimension changes and new bone formation into the socket. Both pairwise and network meta-analysis (NMA) were undertaken to obtain estimates for primary outcomes and compare different grafting materials.

RESULTS

Eighty-eight RCTs were included, with a total of 2805 patients and 3073 sockets. Overall, a total of 1740 sockets underwent alveolar ridge preservation with different materials (1432 were covered by a membrane). Pairwise meta-analysis showed that, as compared to spontaneous healing, all materials statistically significantly reduced horizontal and vertical shrinkage. According to the multidimensional scale ranking of the NMA, xenografts (XG) and allografts (AG), alone or combined with bioactive agents (Bio + AG), were the most predictable materials for horizontal and vertical ridge dimension preservation, while platelet concentrates performed best in the percentage of new bone formation.

CONCLUSIONS

Alveolar ridge preservation is effective in reducing both horizontal and vertical shrinkage, as compared to untreated sockets. NMA confirmed the consistency of XG for ridge dimension preservation, but several other materials and combinations like AG, Bio + AG, and AG + alloplasts, produced even better results than XG in clinical comparisons. Further evidence is needed to confirm the value of such alternatives to XG for alveolar ridge preservation. Bio + AG performed better than the other materials in preserving ridge dimension and platelet concentrates in new bone formation. However, alloplasts, xenografts, and AG + AP performed consistently good in majority of the clinical comparisons.

CLINICAL RELEVANCE

XG and Bio + AG demonstrated significantly better performance in minimizing post-extraction horizontal and vertical ridge dimension changes as compared with other grafting materials or with spontaneous healing, even if they presented the worst histological outcomes. Allografts and other materials or combinations (AG + AP) presented similar performances while spontaneous healing ranked last.

Interventions for replacing missing teeth: alveolar ridge preservation techniques for dental implant site development

BACKGROUND

Alveolar bone changes following tooth extraction can compromise prosthodontic rehabilitation. Alveolar ridge preservation (ARP) has been proposed to limit these changes and improve prosthodontic and aesthetic outcomes when implants are used. This is an update of the Cochrane Review first published in 2015.

OBJECTIVES

To assess the clinical effects of various materials and techniques for ARP after tooth extraction compared with extraction alone or other methods of ARP, or both, in patients requiring dental implant placement following healing of extraction sockets.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 19 March 2021), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2021, Issue 2), MEDLINE Ovid (1946 to 19 March 2021), Embase Ovid (1980 to 19 March 2021), Latin American and Caribbean Health Science Information database (1982 to 19 March 2021), Web of Science Conference Proceedings (1990 to 19 March 2021), Scopus (1966 to 19 March 2021), ProQuest Dissertations and Theses (1861 to 19 March 2021), and OpenGrey (to 19 March 2021). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. A number of journals were also handsearched.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) on the use of ARP techniques with at least six months of follow-up. Outcome measures were: changes in the bucco-lingual/palatal width of alveolar ridge, changes in the vertical height of the alveolar ridge, complications, the need for additional augmentation prior to implant placement, aesthetic outcomes, implant failure rates, peri-implant marginal bone level changes, changes in probing depths and clinical attachment levels at teeth adjacent to the extraction site, and complications of future prosthodontic rehabilitation.

DATA COLLECTION AND ANALYSIS

We selected trials, extracted data, and assessed risk of bias in duplicate. Corresponding authors were contacted to obtain missing information. We estimated mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes, with 95% confidence intervals (95% CI). We constructed 'Summary of findings' tables to present the main findings and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 16 RCTs conducted worldwide involving a total of 524 extraction sites in 426 adult participants. We assessed four trials as at overall high risk of bias and the remaining trials at unclear risk of bias. Nine new trials were included in this update with six new trials in the category of comparing ARP to extraction alone and three new trials in the category of comparing different grafting materials. ARP versus extraction: from the seven trials comparing xenografts with extraction alone, there is very low-certainty evidence of a reduction in loss of alveolar ridge width (MD -1.18 mm, 95% CI -1.82 to -0.54; P = 0.0003; 6 studies, 184 participants, 201 extraction sites), and height (MD -1.35 mm, 95% CI -2.00 to -0.70; P < 0.0001; 6 studies, 184 participants, 201 extraction sites) in favour of xenografts, but we found no evidence of a significant difference for the need for additional augmentation (RR 0.68, 95% CI 0.29 to 1.62; P = 0.39; 4 studies, 154 participants, 156 extraction sites; very low-certainty evidence) or in implant failure rate (RR 1.00, 95% CI 0.07 to 14.90; 2 studies, 70 participants/extraction sites; very low-certainty evidence). From the one trial comparing alloplasts versus extraction, there is very low-certainty evidence of a reduction in loss of alveolar ridge height (MD -3.73 mm; 95% CI -4.05 to -3.41; 1 study, 15 participants, 60 extraction sites) in favour of alloplasts. This single trial did not report any other outcomes. Different grafting materials for ARP: three trials (87 participants/extraction sites) compared allograft versus xenograft, two trials (37 participants, 55 extraction sites) compared alloplast versus xenograft, one trial (20 participants/extraction sites) compared alloplast with and without membrane, one trial (18 participants, 36 extraction sites) compared allograft with and without synthetic cell-binding peptide P-15, and one trial (30 participants/extraction sites) compared alloplast with different particle sizes. The evidence was of very low certainty for most comparisons and insufficient to determine whether there are clinically significant differences between different ARP techniques based on changes in alveolar ridge width and height, the need for additional augmentation prior to implant placement, or implant failure. We found no trials which evaluated parameters relating to clinical attachment levels, specific aesthetic or prosthodontic outcomes for any of the comparisons. No serious adverse events were reported with most trials indicating that the procedure was uneventful. Among the complications reported were delayed healing with partial exposure of the buccal plate at suture removal, postoperative pain and swelling, moderate glazing, redness and oedema, membrane exposure and partial loss of grafting material, and fibrous adhesions at the cervical part of previously preserved sockets, for the comparisons xenografts versus extraction, allografts versus xenografts, alloplasts versus xenografts, and alloplasts with and without membrane.

AUTHORS' CONCLUSIONS

ARP techniques may minimise the overall changes in residual ridge height and width six months after extraction but the evidence is very uncertain. There is lack of evidence of any differences in the need for additional augmentation at the time of implant placement, implant failure, aesthetic outcomes, or any other clinical parameters due to lack of information or long-term data. There is no evidence of any clinically significant difference between different grafting materials and barriers used for ARP. Further long-term RCTs that follow CONSORT guidelines (www.consort-statement.org) are necessary.

Prognosis of single tooth implants following alveolar ridge preservation with two recombinant human bone morphogenetic protein-2 delivery systems

Background

We previously reported similar efficacies of alveolar ridge preservation (ARP) on single extraction socket with two different E. coli derived recombinant human bone morphogenetic protein-2 (rhBMP-2) delivery systems (Cowell BMP, Cowell medi Co, Busan, Korea; β-tricalcium phosphate and hydroxyapatite particle & O-BMP, Osstem Implant Co, Busan, Korea; absorbable collagen sponge). After the trial, we completed implant therapy and observed over an average of 3 years. This follow-up study was performed retrospectively to compare result of implant treatment at the preserved alveolar ridge site.

Methods

Patients who underwent extraction of single tooth and received ARP with one of two rhBMP-2 delivery systems from October 2015 to October 2016 were enrolled. Twenty-eight patients (Group 1: Cowell BMP 14; Group 2: O-BMP 14) who underwent implant therapy and prosthetic treatment were included in study. Stability and marginal bone loss (MBL) of each implant were collected from medical charts and radiographs, and analyzed. The survival and success rates of implants were calculated.

Results

The primary implant stability represented by implant stability quotient (ISQ) for Groups 1 and 2 was 69.71 and 72.86, respectively. The secondary implant stability for Groups 1 and 2 was 78.86 and 81.64, respectively. Primary and secondary stabilities were not statistically different (P = 0.316 and 0.185, respectively). MBL at the latest follow-up was 0.014 mm in Group 1 over 33.76 ± 14.31 months and 0.021 mm in Group 2 over 40.20 ± 9.64 months, with no significant difference (P = 0.670). In addition, the success rate of implants was 100% (14/14) in Group 1 and 92.9% (13/14) in Group 2, with survival rate of 100% (14/14) in Group 1 and 92.9% (13/14) in Group 2.

Conclusions

We confirmed good prognosis in both groups as a result of implant therapy after ARP with each of two rhBMP-2 carriers.

Short-term use of an exposed polypropylene barrier in the preservation of alveolar bone after extraction: randomized clinical trial

This study was performed to evaluate the short-term preservation of alveolar bone volume with or without a polypropylene barrier and exposure of the area after extractions. Thirty posterior tooth extraction sockets were distributed randomly to a control group (n=15; extraction and suture) and a barrier group (n=15; extraction, barrier, and suture). All sutures and barriers were removed 10 days postoperatively. Cone beam computed tomography scans taken with the aid of a tomographic guide were obtained preoperatively, immediately postoperative, and at 120 days postoperative. A visual analysis of the coronal sections of the alveolus was performed, and vertical loss in the mesial, distal, buccal, and lingual bone ridges and horizontal thickness were evaluated. The mean vertical loss after extraction did not differ significantly between the control and barrier groups (Student t-test: mesial P= 0.989, buccal P= 0.997, lingual/palatal P= 0.070, distal P= 0.107). The mean vertical loss at 120 days postoperative did not differ significantly between the control (0.65 mm) and barrier (0.52 mm) groups (P> 0.05), with an effect size of 0.13 mm. At 120 days, the barrier group presented a mean resorption in thickness (0.45 mm) that was significantly lower than that in the control group (0.76 mm) (P= 0.021), with an effect size of 0.31 mm. The polypropylene barrier reduced the horizontal resorption in sockets of posterior teeth after extraction.

Socket seal surgery techniques in the esthetic zone: a systematic review with meta-analysis and trial sequential analysis of randomized clinical trials

Background

The socket seal surgery (SSS) technique is a common alternative for the management of the post-extraction sockets that requires a primary closure of the wound to promote proper regeneration and ridge preservation.

Objective

To learn about the effect of different SSS techniques on alveolar ridge preservation

Material and methods

Two independent and calibrated reviewers conducted an electronic search in PubMed, Cochrane, and Web of Science for randomized clinical trials (RCT) published up to June 2020. The evaluation of the risk of bias in the included studies was carried out following the Cochrane manual for interventions of systematic reviews, version 5.1.0. A meta-analysis of ridge width changes at − 1, − 3, and − 5 mm cutoff points from bone crest was conducted using a random-effects model. The risk of types I and II errors against accrued data was appraised obtaining the required information size using a trial sequential analysis package (TSA).

Results

A total of 135 sockets located in the esthetic zone were evaluated with a minimum of a 3-month follow-up after tooth extraction in 6 RCTs. The evaluated SSS techniques were free gingival graft (FGG), collagen matrix (CM), collagen sponge (CS), acellular dermal matrix (ADM), and polytetrafluoroethylene membrane (PTFEm). The FGG in sockets without bone filling showed significant results in preserving both buccal and lingual bone height (− 1.42 mm in the experimental group versus − 0.01 in the control group). The comparison of CM and FGG with bone filling did not show clinical differences in terms of dimensional bone changes. No clinical differences were found in either width or gingival thickness when comparing CM and CS. The meta-analyses of RW changes comparing CM versus FGG showed no significant differences, but a trend for lessening horizontal reduction at − 1, − 3, and − 5 mm in favor of FGG. The TSA showed that accrued data did not reach the required information size, and more evidence is required for clinical significance inferences.

Conclusions

There are several predictable SSS techniques to improve clinical results in ridge preservation. More clinical studies in the form of clinical trials are required to demonstrate the superiority of one technique over another.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40729-021-00294-2.

Does Platelet-Rich Fibrin Enhance the Early Angiogenetic Potential of Different Bone Substitute Materials? An In Vitro and In Vivo Analysis

The impaired angiogenic potential of bone substitute materials (BSMs) may limit regenerative processes. Therefore, changes in the angiogenetic properties of different BSMs in combination with platelet-rich fibrin (PRF) in comparison to PRF alone, as well as to native BSMs, were analyzed in vitro and in vivo to evaluate possible clinical application. In vitro, four BSMs of different origins (allogeneic, alloplastic, and xenogeneic) were biofunctionalized with PRF and compared to PRF in terms of platelet interaction and growth factor release (vascular endothelial growth factor (VEGF), tissue growth factor ß (TGFß) and platelet-derived growth factor (PDGF)) after 15 min. To visualize initial cell–cell interactions, SEM was performed. In vivo, all BSMs (±PRF) were analyzed after 24 h for new-formed vessels using a chorioallantoic membrane (CAM) assay. Especially for alloplastic BSMs, the addition of PRF led to a significant consumption of platelets (p = 0.05). PDGF expression significantly decreased in comparison to PRF alone (all BSMs: p < 0.013). SEM showed the close spatial relation of each BSM and PRF. In vivo, PRF had a significant positive pro-angiogenic influence in combination with alloplastic (p = 0.007) and xenogeneic materials (p = 0.015) in comparison to the native BSMs. For bio-activated xenogeneic BSMs, the branching points were also significantly increased (p = 0.005). Finally, vessel formation was increased for BSMs and PRF in comparison to the native control (allogeneic: p = 0.046; alloplastic: p = 0.046; and xenogeneic: p = 0.050). An early enhancement of angiogenetic properties was demonstrated when combining BSMs with PRF in vitro and led to upregulated vessel formation in vivo. Thus, the use of BSMs in combination with PRF may trigger bony regeneration in clinical approaches.

Effect of Autogenous Dentin Graft on New Bone Formation

ABSTRACT

The aim of this study is to analyze the effects of autogenous dentin graft and mixture of autogenous dentin graft and platelet-rich fibrin (PRF) applied to the tooth extraction sockets on bone healing process. A total of 57 extraction sockets in 9 patients who were planned to be treated with dental implant after tooth extraction were evaluated in this study. Extraction sockets were divided randomly into 3 groups for each patient. In the first group, sockets were filled with autogenous dentin graft (Group D). In the second group, sockets were filled with the mixture of PRF and autogenous dentin graft (Group DP). In the third group, sockets were left empty as the control group (Group C). After 3 months, histological and immunohistochemical evaluations were performed on the samples taken during the implant surgery. Additionally, samples obtained from each group were examined by scanning electron microscopy. According to the histopathological findings, when the groups were compared in terms of new bone formation there was a significant difference between Group DP, both Group C, and Group D (P = 0.00), (P = 0.001). These findings supported by immunohistochemical results that showing increased bone morphogenetic protein-2 and Runt-related transcription factor-2 expression in Group DP. It has been concluded that undemineralized autogenous dentin graft has bone formation capacity on early period of bone healing. It can be used as bone graft material in augmentation procedures and its combined use with PRF accelerates new bone formation.