Platelet-Rich Fibrin in Maxillary Sinus Augmentation: A Systematic Review

Prevention and management of intra-operative complications in maxillary sinus augmentation: A review

Maxillary sinus floor elevation is usually performed in two different ways: the lateral approach involves the creation of a bony window on the maxillary sinus lateral wall, providing direct access to the sinus cavity for membrane elevation and subsequent graft placement, and the transcrestal approach is considered less invasive. The aim of this article is to describe, based on the literature, how to anticipate, avoid, and manage the intraoperative complications that can occur with both approaches. For both approaches, the most common complication is the sinus membrane perforation. For the lateral approach, an average frequency ranging from 15.7% to 23.1% is reported, but because of the better visibility, their management will be easier compared to the transcrestal approach. Mean perforation rate reported for the transcrestal approach is lower (3.1%-6.4%), but it should be noted that a significant number of perforations cannot be detected and managed given the blind nature of this technique. Anatomical parameters such as sinus width and buccal wall thickness may be a risk factor for one approach and not the other. As it is impossible to assess the resistance of the Schneiderian membrane, the transcrestal approach is more likely to lead to infectious complications in the event of perforation. Others, such as the risk of vascular damage, are encountered only with the lateral approach, which can be prevented easily by dissecting the alveolo-antral artery. For both approaches, prevention is essential and consists in analyzing the anatomy, mastering the surgical technique, and collaborating with the ENT to manage the essentially infectious consequences of intraoperative complications.

Effectiveness of Autologous Platelet Concentrates in the Sinus Lift Surgery: Findings from Systematic Reviews and Meta-Analyses

Maxillary sinus augmentation is one of the most predictable procedures for the rehabilitation of the posterior maxilla. The current overview aimed to summarize the findings provided by systematic reviews (SRs) and meta-analyses on the effectiveness of autologous platelet concentrates (APCs) in sinus lift and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs and meta-analyses addressing the effectiveness of APCs in sinus lift technique were included. Clinical, radiographic and histomorphometric findings were considered for APCs as solely grafting materials and APCs in combination with biomaterials. Outcomes were implant survival rate (ISR), implant stability (IS), implant failure (IF), postoperative complications, histomorphometric findings, radiographic bone gain, bone volume and bone density. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Thirty SRs were included. The methodological quality of the included reviews ranged from critically low (3 studies) to high (9 studies). The included SRs showed favorable clinical outcomes, short-term new bone formation and no biological complications when APCs were used both as solely graft material or in combination with other biomaterials. However, no significant additional effects in the long-term period were observed. APCs did not add any further positive effects compared to the physiological healing derived by the natural blood clot. The current overview of SRs highlighted the need for high-quality SRs evaluating the role of APCs in sinus lift though network meta-analyses, in order to identify the most powerful material for sinus lift augmentation. The use of APCs improves the healing of soft tissues and the postoperative quality of life in the short-term period. Thus, its application can be recommended.

The Use of Platelet-Rich Fibrin in Sinus Floor Augmentation Surgery: a Systematic Review

Objectives

This systematic review aims to critically assess the impact of platelet-rich fibrin on maxillary sinus floor augmentation and outline the specific aspects of new bone formation, bone height, implant stability quotient, and Schneiderian membrane thickness.

Material and Methods

A systematic review and meta-analysis were conducted, analysing studies from MEDLINE (PubMed), the Cochrane Library, and ScienceDirect databases, published from January 29, 2018 until January 29, 2024 that compared maxillary sinus floor augmentation (MSFA) using bone graft material with and without platelet-rich fibrin (PRF). This review focused on patients 18 years and older who undergone MSFA before the dental implant placement. It systematically examined five studies, encompassing randomized controlled trials, and reported on 112 MSFA procedures conducted in 84 patients.

Results

The meta-analysis reveals a marginal significance in new bone formation with PRF, suggesting a trend towards beneficial outcomes that were not statistically significant. No significant impact on bone height was observed. However, a notable improvement in implant stability quotient (ISQ) was recorded, indicating enhanced implant stability with PRF. The Schneiderian membrane thickness did not show significant changes post-treatment with PRF.

Conclusions

While platelet-rich fibrin shows promise in enhancing implant stability, its effects on new bone formation and Schneiderian membrane thickness are inconclusive, highlighting the need for further research. Platelet-rich fibrin did not significantly affect bone height. The findings support platelet-rich fibrin's potential as a beneficial adjunct in maxillary sinus floor augmentation, particularly for implant stability.

Effect of thermal manipulation on the biological and mechanical characteristics of horizontal platelet rich fibrin membranes

BACKGROUD

Regardless of application scenarios, proper mechanical characteristics and degradation properties are prerequisites for horizontal platelet rich fibrin (H-PRF) to manifest its ability. Among the methods used to modify PRF, thermal manipulation is promising as it is easy to handle without adding extra additives. Yet there is no consensus on optimal temperature treatment. This study aimed to investigate the effects of heating on the biological and mechanical characteristics of H-PRF and explore the optimum heating temperature for H-PRF thermal treatment.

METHODS

We employed a series of temperature gradients, room temperature, 50℃, 75℃, 90℃, 105℃. The microstructure and the mechanical properties were recorded by Scanning Electron Microscope (SEM) and tensile strength tests respectively. The degradation rate of H-PRF membranes was examined by digestion assay with plasmin and trypsin. The viability of cells within H-PRF membranes and the proliferation of osteoblasts cultured with extracts from different H-PRF groups was evaluated using CCK-8 assays.

RESULTS

Compared with the nonheated group, overheated manipulation beyond 90℃ can significantly prolong the degradation properties for up to 3 to 4 weeks and enhance the mass stress of H-PRF membranes. A high-temperature treatment of 105℃ accompanied by the cell activity beneath H-PRF reduced more than half, and thus, the biological effect on human osteoblasts (hFOBs) also reduced dramatically.

CONCLUSIONS

High thermal manipulation can prolong the degradation properties and enhance the mechanical properties of PRF membranes accompanied by the loss of biological effect.

Early tissue and healing responses after maxillary sinus augmentation using horizontal platelet rich fibrin bone blocks

BACKGROUND

The effects of horizontal platelet-rich fibrin (H-PRF) bone block on the healing and immune response during sinus augmentation have not been fully investigated histologically at early time points.

METHODS

Eighteenth male New Zealand white rabbits underwent bilateral sinus augmentation and were divided into two groups: deproteinized bovine bone mineral (DBBM) alone and H-PRF + DBBM (H-PRF bone block) group. Maxilla samples were collected at 3, 7 and 14 days post sinus augmentation procedures and analyzed using histological staining for the number of inflammatory cells, new blood vessels and evidence for early osteoclast bone turnover/remodeling. Furthermore, the effects of H-PRF bone blocks on the migration of osteoblasts and THP-1 macrophages were evaluated using a Transwell assay in vitro.

RESULTS

A higher number of immune cells were found in the H-PRF bone block group at 3 and 7 days post-surgery when compared to the DBBM alone group,most notably in the regions close to the mucosal lining and bone plates. Furthermore, a significantly greater number of new blood vessel formations and early signs of osteoclast development were found in the H-PRF bone block group at 14 days. The in vitro transwell assay further confirmed that culture medium from H-PRF bone block markedly promote the migration of osteoblasts and THP-1 macrophages.

CONCLUSIONS

The findings from this study have shown that H-PRF bone block is capable of increasing early immune cell infiltration leading to the acceleration of neovascularization and speeding the process of bone metabolism in vivo following maxillary sinus grafting with DBBM.

The Effectiveness of the Addition of Platelet-Rich Fibrin to Bovine Xenografts in Sinus and Bone Ridge Augmentation: A Systematic Review

Dental implants sometimes need bone augmentation to recreate an adequate bone height and volume. Numerous bone augmentation techniques have been described, and, currently, the most commonly used bone graft procedure is xenografts with deproteinized bovine bone mineral (DBBM). The addition of platelet-rich fibrin (PRF) to DBBM has already shown better performance than DBBM alone in restoring intrabony periodontal defects, but the role of PRF in preimplantation bone grafts is still not clear. The objective of this systematic review was to evaluate the efficacy of the adjunction of PRF or L-PRF to DBBM in bone ridge augmentation procedures. Clinical randomized controlled studies using PRF associated with DBBM were included. In April 2023, three electronic databases (PubMed, Cochrane, and Web of Science) were searched. The search strategy was performed according to PRISMA guidelines. The risk of bias assessments were performed using the Cochrane Collaboration tool. A total of seven articles were included and analyzed. The results show no statistically significant effect of PRF added to DBBM compared to DBBM alone in the sinus lift procedure but do show an effect in the reduction in bone graft resorption in one study of mandibular guided bone regeneration.

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.

Onlay platelet-rich fibrin membrane versus free gingival graft in increasing the width of keratinized mucosa around dental implants: A split-mouth randomized clinical study

Background. This study aimed to compare the use of the platelet-rich fibrin membrane (PRF) versus the free gingival graft (FGG) during the second stage of the dental implant to increase the amount of keratinized mucosa around dental implants. Methods. Fifteen patients with bilaterally missing teeth and deficient width of the keratinized mucosa (KM) were recruited for a spit-mouth randomized controlled trial. After implant placement on the control sides, onlay FGG was used, whereas, on the other side (study side), onlay PRF membranes were applied to augment the KM. One month and three months after augmentation, the increase in keratinized mucosa width, bone level around the implants, and soft tissue health were evaluated and compared. The shrinkage percentage was also calculated for both grafts. Results. There was a significant increase in the width of KM in the FGG and PRF groups; however, it was observed that FFG resulted in significantly better results than PRF, with no significant difference in peri-implant soft tissue health or bone level. Conclusion. Within the limitations of this study, it was concluded that the onlay PRF membrane could increase the keratinized mucosa width around dental implants with the advantages of a lower surgical time and less postoperative discomfort and pain for the patients in comparison to the FGG. However, FGG had a significantly higher ability to augment and increase keratinized mucosa around dental implants.

Effect of Sinus Floor Augmentation with Platelet-Rich Fibrin Versus Allogeneic Bone Graft on Stability of One-Stage Dental Implants: A Split-Mouth Randomized Clinical Trial

Rehabilitation of an edentulous posterior maxilla with dental implants is challenging, and sinus floor augmentation could be considered as an important surgical procedure for bone augmentation in this region before implant placement. Platelet-rich fibrin (PRF) is a new-generation platelet concentrate with simplified processing: its application in sinus floor augmentation has been widely investigated in literature. However, the biological properties and actual efficacy of this product remain controversial. This study assessed the effect of sinus floor augmentation with PRF versus freeze-dried bone allograft (FDBA) on stability of one-stage dental implants. This split-mouth randomized clinical trial evaluated 10 patients who required bilateral sinus floor augmentation. PRF and L-PRF membrane were used in one quadrant while FDBA and collagen membrane were used in the other quadrant. Implant stability was assessed by resonance frequency analysis (RFA) immediately, and 2, 4, and 6 months after implant placement. The implant stability quotient (ISQ) was compared over time and between the two groups using repeated measures ANOVA and independent sample t-test. The mean ISQ significantly increased over time in both groups (p < 0.001). The increase was greater in the PRF group (p < 0.05). Within the limitations of this study, PRF yielded superior results compared with FDBA regarding the stability of one-stage dental implants.

Advanced Biomaterials, Coatings, and Techniques: Applications in Medicine and Dentistry

The field of biomaterials is very extensive, encompassing both the materials themselves and the manufacturing methods, which are constantly developing [...]

Comparison of the effects of platelet concentrates produced by high and low-speed centrifugation protocols on the healing of critical-size defects in rat calvaria: a microtomographic and histomorphometric study

The current study evaluated the healing of critical-size defects (CSD) created in rat calvaria treated with platelet concentrates produced by high-speed (Leukocyte- and Platelet-Rich Fibrin - L-PRF) and low-speed (Advanced Platelet-Rich Fibrin - A-PRF) protocols of centrifugation. Twenty-four rats were distributed into three groups: Control, L-PRF, and A-PRF. Five mm diameter CSD were created on the animals' calvaria. The defects of the L-PRF and A-PRF groups were filled with 0.01 ml of L-PRF and A-PRF, respectively. The control group defects were filled with a blood clot only. All animals were euthanized on the 35th postoperative day. Histomorphometric and microtomographic analyses were then performed. The L-PRF and A-PRF groups had significantly higher bone volume and neoformed bone area than those of the control group and lowered bone porosity values (p < .05). No significant differences were observed between A-PRF and L-PRF groups for the analyzed parameters. Therefore, it can be concluded that i) L-PRF and A-PRF potentiated the healing of CSD in rat calvaria; ii) high and low-speed centrifugation protocols did not produce PRF matrices with different biological impacts on the amount of bone neoformation.

"Sticky Bone" Preparation Device: A Pilot Study on the Release of Cytokines and Growth Factors

Sticky bone, a growth factor-enriched bone graft matrix, is a promising autologous material for bone tissue regeneration. However, its production is strongly dependent on manual handling steps. In this sense, a new device was developed to simplify the confection of the sticky bone, named Sticky Bone Preparation Device (SBPD®). The purpose of this pilot study was to investigate the suitability of the SBPD® to prepare biomaterials for bone regeneration with autologous platelet concentrates. The SBPD® allows the blending of particulate samples from synthetic, xenograft, or autogenous bone with autologous platelet concentrates, making it easy to use and avoiding the need of further manipulations for the combination of the materials. The protocol for the preparation of sticky bone samples using the SBPD® is described, and the resulting product is compared with hand-mixed SB preparations regarding in vitro parameters such as cell content and the ability to release growth factors and cytokines relevant to tissue regeneration. The entrapped cell content was estimated, and the ability to release biological mediators was assessed after 7 days of incubation in culture medium. Both preparations increased the leukocyte and platelet concentrations compared to whole-blood samples (p < 0.05), without significant differences between SB and SBPD®. SBPD® samples released several growth factors, including VEGF, FGFb, and PDGF, at concentrations physiologically equivalent to those released by SB preparations. Therefore, the use of SBPD® results in a similar product to the standard protocol, but with more straightforward and shorter preparation times and less manipulation. These preliminary results suggest this device as a suitable alternative for combining bone substitute materials with platelet concentrates for bone tissue regeneration.

Platelet concentrates in periodontics: review of in vivo studies and systematic reviews

Clot formation is the first step of the healing process, and clinical procedures always find ways to stabilize this clot better. Platelets play a significant role in clot formation, and Platelet Concentrates (Pc) are an abundant reservoir of platelets. This article aims to review the in vitro research and systematic reviews on PCs that are currently available. Broadly, PCs mainly include Platelet-rich plasma and platelet-rich fibrin. PCs are an excellent source for growth factors such as PDGF-AA, TGF β1, VEGF, EGF, and IGF. Numerous systematic reviews and meta-analyses have analyzed the clinical application of PCs in various periodontal procedures. In alveolar ridge preservation, PCs are known to reduce postoperative pain, edema, trismus, and inflammation. PRF had shown significant improvement in achieving root coverage and recession depth reduction. PCs exhibited a positive influence on CAL gain when used as an adjunct to OFD in treating infra-bony defects. Pcs have a positive effect on bone maturation in the short term. Besides, PCs can be used in regenerative endodontics, treatment of medication-related osteoradionecrosis of Jaw (MRONJ), and accelerating tooth movement. In conclusion, PCs positively affect soft tissue healing, while their role in hard tissue healing is still unclear.

Structure, Barrier Function, and Bioactivity of Platelet-Rich Fibrin Following Thermal Processing

Platelet-rich fibrin (PRF) has been utilized as a substitute for resorbable membranes during guided bone regeneration therapy as it is a more bioactive biomaterial with living cells and growth factors than resorbable membranes. Nevertheless, PRF poses obvious disadvantages in its mechanical strength since its rapid degradability has been shown to typically resorb within a 2-week time period. In the present study, the barrier function and biological and mechanical properties of PRF were investigated both as standard therapy and after thermal processing. Two heating processes were applied: both single-side heating and double-side heating at 90°C for 10 s using a metal plate heater. The appearance and weight of PRF membranes were documented after heating, along with their morphological and mechanical properties evaluated by scanning electron microscope and tensile strength tests. The viability of cells found within PRF membranes was also evaluated using live/dead cell viability and CCK-8 (cell counting kit-8) assays. To comprehensively evaluate the barrier function of PRF membranes, Hoechst staining of human gingival fibroblasts, which can be distinguished from cells within the PRF membrane by emitting blue light at an excitation wavelength of 488 nm, was seeded onto the surface of PRF membranes. Furthermore, osteoblasts were cultured with extracts from different PRF groups to evaluate the biocompatibility of PRF membranes. The degradation rate of PRF membranes was examined by digestion assay. Compared with the nonheated PRF control, the size and weight of PRF membranes led to a significant decrease with a denser PRF microstructure following heating. In summary, the double-sided heating of PRF membranes not only demonstrated an improvement in mechanical and degradation properties but also led to a decrease in cell viability and proliferation.

Patient-centered comparative outcome analysis of platelet-rich fibrin-reinforced vestibular incision subperiosteal tunnel access technique and Zucchelli's technique

Background:

Multiple gingival recession (MGR) coverage, especially in esthetic area, demands a high patient satisfaction. Coronally advanced flap modifications, namely Zucchelli's technique (ZT) and vestibular incision subperiosteal tunnel access (VISTA), are techniques, recommended in the correction of MGR.

Aim:

The purpose was to comparatively analyze the ZT and VISTA technique reinforced with the platelet-rich fibrin membrane in the management of MGR.

Materials and Methods:

This split-mouth, randomized study comprised 16 consenting, systemically healthy participants. The bilateral Miller's multiple class I and II lesions were managed with ZT and VISTA technique and had a follow-up period of 18 months. Gingival thickness (GT), mean percentage of root coverage, and patient-centered outcome scales, including patient comfort score, patient esthetic score, and hypersensitivity score, were the primary outcome measures. Further clinical parameters assessed were gingival index, probing depth, clinical attachment level, and width of keratinized gingiva.

Statistical Analysis and Results:

Paired t-test and unpaired t-test were used for intragroup comparison and intergroup analysis, respectively. While both the techniques exhibited high root coverage percentage (VISTA: 93.95% and ZT: 96.84%), statistically significant difference was noted with patient esthetic score and surgical mortality score in VISTA.

Conclusion:

Both ZT and VISTA were effective in terms of root coverage and GT augmentation in MGR management. From the patient's perspective, they preferred VISTA technique over ZT, stating its minimal postoperative morbidity and improved esthetic outcome. Hence, within the limitations of this study, the VISTA technique was found to be a superior alternative compared to that of ZT in MGR management.

Transcrestal sinus augmentation with simultaneous implant placement in 1 to 2 mm residual alveolar bone: a case report

An abstract is not required.

Minimally invasive maxillary sinus augmentation with simultaneous implantation on an elderly patient: A case report

BACKGROUND

In this case study, a minimally invasive transalveolar approach using platelet-rich fibrin and bone substitute with simultaneous implantation was carried out in an elderly patient. We analyzed the cone-beam computed tomography (CBCT) findings to evaluate bone regeneration.

CASE SUMMARY

A 65-year-old female with no contraindications for dental implants and loss of maxillary bilateral molars is described. Examination by CBCT showed the available vertical bone height in the bilateral posterior maxilla was 0.5-6.8 mm in the left and 2.8-6.5 mm in the right. The patient underwent a transalveolar approach using platelet-rich fibrin and bone substitute with simulataneous placement of an implant 10 mm in length. Six months post-surgery, the implant showed excellent osseointegration with the bone graft. Thereafter, full-ceramic crowns were fitted. Follow-up at 2 years demonstrated satisfactory prognosis.

CONCLUSION

Platelet-rich fibrin and bone substitute can be used to augment the maxillary sinus with a vertical bone height less than 4 mm.

Evidence-Based Clinical Efficacy of Leukocyte and Platelet-Rich Fibrin in Maxillary Sinus Floor Lift, Graft and Surgical Augmentation Procedures

Bone augmentation techniques have increasingly been indicated for re-creating adequate bone height and volume suitable for dental implant sites. This is particularly applicable in the severely atrophic posterior maxilla where sinus perforation (ruptured Schneiderian membrane) is a very common complication and sinus floor elevation or lift is frequently considered a standard procedure. The augmentation of the maxillary sinus can be performed with or without grafting biomaterials. Herein, numerous biomaterials and bone substitutes have been proposed, primarily to sustain the lifted space. In addition, cytokines and growth factors have been used to stimulate angiogenesis, enhance bone formation as well as improve healing and recovery period, either as the sole filling material or in combination with bone substitute materials. Within such, is the family of autologous blood extracts, so-called platelet concentrates, which are simply the "product" resulting from the simple centrifugation of collected whole blood samples of the patient, immediately pre-surgery. Platelet-Rich Fibrin (PRF), a sub-family of platelet concentrates, is a three-dimensional (3-D) autogenous biomaterial obtained, without including anti-coagulants, bovine thrombin, additives, or any gelifying agents during the centrifugation process. Today, it is safe to say that, in implant dentistry and oral and maxillofacial surgery, PRFs (particularly, the pure platelet-rich fibrin or P-PRF and leukocyte and platelet-rich fibrin or L-PRF sub-classes) are receiving the most attention, essentially due to their simplicity, rapidness, user-friendliness/malleability, and cost-effectiveness. Whether used as the sole "bioactive" filling/additive material or combined with bone substitutes, the revolutionary second-generation PRFs have been very often associated with promising clinical results. Hence, this review aims to provide a 10-years update on the clinical effectiveness of L-PRF when applied/used as the "sole" biomaterial in maxillary sinus augmentation procedures. An electronic search using specific keywords for L-PRF and maxillary sinus augmentation was conducted in three main databases (PubMed-MEDLINE database, Google Scholar and Cochrane library) for the period between January 2009-February 2020. The quest yielded a total of 468 articles. Based on the pre-established strict inclusion/exclusion criteria, only seven articles were deemed eligible and included in the analysis. Surprisingly, of the 5 studies which used de-proteinized bovine bone mineral (DBBM) in combination with L-PRF, 60% acclaimed no significant effects and only 40% declared positive effects. Of the two articles which had used allogenous bone graft, 50% declared no significant effects and 50% acclaimed positive effects. Only one study had used L-PRF as the sole grafting material and reported a positive effect. Likewise, positive effects were reported in one other study using L-PRF in combination with a collagen membrane. Due to the heterogeneity of the included studies, this review is limited by the inability to perform a proper systematic meta-analysis. Overall, most of the published studies reported impressive results of L-PRF application as a grafting material (sole or adjuvant) in maxillary sinus augmentation and dental implant restorative procedures. Yet, distinct technical processing for L-PRF preparation was noted. Hence, studies should be approached with caution. Here in, in sinus lift and treatment of Schneider membrane, the formation of mature bone remains inconclusive. More studies are eagerly awaited in order to prove the beneficial or detrimental effects of PRFs, in general and L-PRFs, in specific; especially in their tissue regenerative potential pertaining to the promotion of angiogenesis, enhancing of cell proliferation, stimulation of cell migration and autocrine/paracrine secretion of growth factors, as well as to reach a consensus or a conclusive and distinct determination of the effect of leukocytes (and their inclusion) on inflammation or edema and pain; a call for standardization in PRFs and L-PRFs composition reporting and regimenting the preparation protocols.

Pathogen Reduction Technology: A Novel Possibility for Inactivation of Blood Products Used in Oral and Periodontal Surgeries

Emergency surgical treatment has been challenging and the risk of blood contamination has been high, which is a concern among the medical and dental fraternity. The risk outweighs the benefits in these unprecedented times if proper screening and inactivation of blood products are not performed. Pathogen reduction technologies incorporate various modalities for the inactivation of blood products mainly related to blood transfusion. Oral surgical procedures and periodontal surgeries use platelet-rich fibrin for various regenerative procedures that amplify the prognosis positively. The use of blood products for various treatments could result in contamination, a factor which should be significant attention. The objective of this study was to review the role of pathogen reduction technology in inactivating pathogens in blood products and its use in oral and periodontal surgical procedures. The literature presented in the study is from original studies from a period of 2000 to 2020 which was sourced from Medline, PubMed, and Cochrane central databases. Relevant published papers and in-press papers that provided information were identified and selected. The studies presented have shown data related to implementation of pathogen reduction technologies in relation to the severe acute respiratory syndrome, Middle East respiratory syndrome, and its possible implementation in coronavirus disease-2019 (COVID-19). The paper reviews the various technologies offered and the possibility to eradicate pathogens found in routine blood products, used in oral and periodontal surgical procedures. In all probability, the use of pathogen reduction technology might offer a ray of light to contain the spread among dental treatment procedures.

The Effect of Autologous Platelet Concentrates on Maxillary Sinus Augmentation: A Meta-Analysis of Randomized Controlled Trials and Systematic Review

INTRODUCTION

To assess the efficacy of the autologous platelet concentrates (APCs) combined with autologous bone or bone substitute for the maxillary sinus floor lifting by a meta-analysis.

MATERIALS AND METHODS

Electronic databases (PUBMED, Web of Science, EMBASE through OVID, and Cochrane Library) were searched until Dec 31, 2019, and only randomized controlled trials (RCTs) in English were identified. Outcome variables included histologic evaluation, the implant stability quotient values, and radiographic evaluation. Data were analyzed by Revman5.3; the estimate of effect sizes was expressed as the 95% confidence interval; and the risk of bias was evaluated using the Cochrane Collaboration tool.

RESULTS

11 RCTs involving 141 patients (214 sites) were included in our meta-analysis, which indicated that the differences in the percentage of contact length among newly formed bone (2.61%, 95% CI, -1.18% to 7.09%), soft tissue area (-0.15%, 95% CI, -0.54% to 0.24%), and residual bone substitute material (-5.10%, 95% CI, -10.56% to 0.36%) in the APC group lacked statistical significance. Besides, there was the same effect on the implant stability quotient (ISQ) values of APC group who underwent implant placement 4 months after sinus augmentation and control group who received implant placement 8 months after sinus augmentation (-0.48, 95% CI, -1.68 to 0.72). No significant effect of APCs on the bone density was found (1.05%, 95% CI, -1.69% to 3.82%).

CONCLUSIONS

The use of APCs in sinus augmentation may be further shorten the time required for bone graft maturation and allow earlier implant placement, but cannot enhance the bone formation in the long term. It is not currently recommended for routine use APCs as an osteoinductive material to bone grafting in sinus augmentation.

Does platelet-rich fibrin increase stability of the maxilla following Le Fort I osteotomy? A single-blind clinical trial study

This single-blind clinical trial study aimed to assess the efficacy of platelet-rich fibrin (PRF) in increasing stability following Le Fort I osteotomy for maxillary advancement. Patients who underwent Le Fort I osteotomy for maxillary advancement were assigned randomly into two groups: in group 1 (the study group, n = 22) PRF was placed in the osteotomy sites following fixation, while no PRF was used in group 2 (the control group, n = 22). Lateral cephalograms obtained preoperatively (T0), immediately after surgery (T1), and 1 year after surgery (T2) were compared between the two groups, and the amount of relapse was determined. The amount of maxillary change (relapse) at the A point in relation to the x-axis was 0.45 ± 0.67 mm in group 1 and 1.86 ± 0.56 mm in group 2. There was a significant difference in mean relapse in relation to the x-axis between the two groups 12 months after osteotomy (p < 0.001). The mean maxillary change (relapse) in relation to the y-axis was 0.77 ± 1.15 mm in group 1 and 2.25 ± 1.22 mm in group 2. Analysis of the data demonstrated a significant difference in mean relapse in relation to the y-axis between the two groups (p < 0.001). PRF may enhance the stability of the maxilla following Le Fort I osteotomy. Based on the results of this study the administration of PRF should be considered whenever possible.

Maxillary Sinus Augmentation Using Xenograft and Choukroun's Platelet-Rich Fibrin as Grafting Material: A Radiological Study

Aim

The objective of the study was to assess the efficacy of xenograft (BIO-OSS) and platelet-rich fibrin in maxillary sinus augmentation using lateral window approach.

Materials and Methods

A total of 22 direct sinus lifts were done within a period of two years, and the results were analyzed using two parameters: (1) augmented bone height and (2) bone density in the maxillary sinus. Pre-operative and three-month CT scan was taken for all the 22 patients. Bone densities were calculated using CT scan, and the results were compared between xenograft (BIO-OSS) and platelet-rich fibrin (PRF).

Results

Statistical analysis of the two groups was performed using independent t test and paired t test, and results were tabulated.

Combination of an allogenic and a xenogenic bone substitute material with injectable platelet-rich fibrin - A comparative in vitro study

The aim of the in vitro study was a comparison of an allogenic (ABSM) and a xenogenic bone substitute material (XBSM) with and without injectable platelet-rich fibrin (ABSM-i-PRF & XBSM-i-PRF) on cell characteristics of human osteoblasts (HOB). Here, ABSM and XBSM (+ i-PRF = test; - i-PRF = control) were incubated with HOB for 3, 7 and 10 days. HOB viability, migration, proliferation and differentiation (RT-PCR on alkaline phosphatase (AP), bone morphogenetic protein 2 (BMP-2) and osteonectin (OCN)) were measured and compared between groups. At day 3, an increased viability, migration and proliferation was seen for ABSM-i-PRF. For viability and proliferation (days 7 and 10) and for migration (day 10), ABSM-i-PRF/XBSM-i-PRF showed higher values compared to ABSM/XBSM with maximum values for ABSM-i-PRF and minimum values for XBSM. At days 3 and 7, the highest expression of AP was detected in ABSM-i-PRF/XBSM-i-PRF when compared to ABSM/XBSM, whereas at day 10, AP expression levels were elevated in ABSM-i-PRF/ABSM. The highest BMP-2 expression was seen in ABSM-i-PRF whereas OCN expression showed higher levels in ABSM-i-PRF/XBSM-i-PRF at days 3 and 7 with lowest expression for ABSM. Later on, elevated OC levels were detected for ABSM-i-PRF only. In conclusion, i-PRF in combination with ABSM enhances HOB activity when compared to XBSM-i-PRF or untreated BSM in vitro. Therefore, addition of i-PRF to ABSM and - to a lower extent - to XBSM may influence osteoblast activity in vivo.

Platelet-Rich Plasma in Maxillary Sinus Augmentation: Systematic Review

Background: Sinus augmentation can be performed with or without grafting biomaterials, and to date, there is no quality evidence regarding the augmentation of the sinus floor using only platelet concentrates, which can improve the healing period and enhance bone regeneration by stimulating angiogenesis and bone formation. The main objective of this paper was to assess the effect of the sole use of platelet concentrates in sinus augmentation in terms of newly formed bone, augmented bone height, and clinical outcomes and to assess the additional beneficial effects of platelet-rich fibrin (PRF) in combination with other grafting biomaterials. Methods: A systematic review was conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Pooled analyses were performed with the Review Manager software. Results: For sinus elevation only using platelet concentrates, 11 studies met the inclusion criteria and were included for qualitative synthesis. Only one study was a clinical trial, which reported improved outcomes for the allograft group compared to the titanium-PRF (T-PRF) group. A total of 12 studies where PRF was used in addition to grafting biomaterials met eligibility criteria and were included in the review. Results from meta-analyses provided no additional beneficial effects of PRF in sinus augmentation in terms of bone height and percentage of soft tissue area. There was a statistically significant lower percentage of residual bone substitute material in the PRF (+) group compared to the PRF (−) group. The percentage of newly formed bone was slightly higher in the PRF (+) group, but this was not statistically significant. Conclusion: There is no robust evidence to make firm conclusions regarding the beneficial effects of the sole use of platelet concentrates in sinus augmentation. However, studies have shown favorable outcomes regarding implant survival, bone gain, and bone height. The use of PRF with other grafting biomaterials appears to provide no additional beneficial effects in sinus lift procedures, but they may improve the healing period and bone formation. Well-conducted randomized clinical trials (RCTs) are necessary to confirm the available results to provide recommendations for the clinical practice.

Extra-Long Nasal Wall-Directed Dental Implants for Maxillary Complete Arch Immediate Function: A Pilot Study

Immediate loading of maxillary denture prostheses in the context of severe bone atrophy is complicated by posterior implant placement, sometimes requiring a complex surgical approach as zygomatic or pterygoid implants. To overcome this complexity, the authors developed an extra-long (20-24 mm) 24-degree angulated platform. It was tested on 33 patients, with 24 patients immediately loaded (72.7%) for a total of 115 implants (46% nasal). All delayed loading implants osseointegrated. Eight bilateral and six unilateral sinus grafts were performed. There were no complications during the follow-up period.

Regenerative Effect of Platelet Concentrates in Oral and Craniofacial Regeneration

Platelet concentrates (PCs) are biological autologous products derived from the patient's whole blood and consist mainly of supraphysiologic concentration of platelets and growth factors (GFs). These GFs have anti-inflammatory and healing enhancing properties. Overall, PCs seem to enhance bone and soft tissue healing in alveolar ridge augmentation, periodontal surgery, socket preservation, implant surgery, endodontic regeneration, sinus augmentation, bisphosphonate related osteonecrosis of the jaw (BRONJ), osteoradionecrosis, closure of oroantral communication (OAC), and oral ulcers. On the other hand, no effect was reported for gingival recession and guided tissue regeneration (GTR) procedures. Also, PCs could reduce pain and inflammatory complications in temporomandibular disorders (TMDs), oral ulcers, and extraction sockets. However, these effects have been clinically inconsistent across the literature. Differences in study designs and types of PCs used with variable concentration of platelets, GFs, and leucocytes, as well as different application forms and techniques could explain these contradictory results. This study aims to review the clinical applications of PCs in oral and craniofacial tissue regeneration and the role of their molecular components in tissue healing.

[Effects of concentrated growth factors on relieving postoperative reaction of guided bone regeneration in the esthetic zone]

OBJECTIVE

To explore the effect of concentrated growth factors (CGF) on postoperative pain and swelling in patients with complex dental implants.

METHODS

A total of 28 patients with single maxillary anterior teeth loss and labial orbital bone defect were recruited randomly and divided into two groups. Each group included 14 patients. The experimental group was applied with CGF membrane to guide bone regeneration, whereas the control group was treated with collagen membrane to guide bone regeneration. The postoperative pain degree and swelling degree were compared, and data were analyzed with SPSS 23.0 software. Postoperative pain was measured by visual analogue scale (VAS), and the degree of swelling was divided into four grades according to swelling range.

RESULTS

VAS scores of patients in experimental and control groups reached 35.1±22.5 and 47.0±20.3, respectively. The duration of postoperative pain in experimental and control groups totaled (2.1±1.5) and (2.8±1.0) days, respectively. No statistically significant difference was observed between the two groups (P>0.05). Percentages of non-swelling, mild swelling, moderate swelling, and severe swelling in experimental group reached 21.4%, 57.1%, 21.4%, and 0, respectively, and those in control group were 7.1%, 35.7%, 35.7%, and 21.4%. Swelling duration reached (2.4±1.4) and (4.2±2.2) days in the experimental and control groups, respectively. A statistically significant difference was observed in the swelling degree of experimental and control groups (P<0.05).

CONCLUSIONS

The use of CGF can significantly reduce the degree of postoperative swelling and shorten swelling time but cause no significant effect on pain.

Autologous Fibrin Glue With Collagen Carrier During Maxillary Sinus Lift Procedure

This study aimed to describe the use of autologous fibrin glue (AFG) with a collagen carrier during maxillary sinus lift procedures with immediate implants during 3 years of follow-up. Twelve patients who had lost their teeth in the region associated to maxillary sinus, with a bone remnant 3 to 5 mm in height, were selected to perform a maxillary sinus augmentation with AFG and collagen membrane, placing the implant immediately. After 5 months, the implants were connected and rehabilitated. The patients were followed-up for a 3-year period, being evaluated every 6 months. At the end of the 3-year follow-up period, 100% implant success was observed, with a mean of bone augmentation of 7.75 mm. Three maxillary sinus membranes were perforated and healed by using AFG and collagen membrane without identify any complication during the follow-up period. Finally, the use of collagen carrier combined with AFG as a filling material during the maxillary sinus lift procedure may be a low-cost and reliable alternative that allows bone formation.

Platelet-Rich Fibrin and its Emerging Therapeutic Benefits for Musculoskeletal Injury Treatment

New therapies that accelerate musculoskeletal tissue recovery are highly desirable. Platelet-rich fibrin (PRF) is a leukocyte- and platelet-rich fibrin biomaterial that acts as a binding site for both platelets and growth factors. Through increasing the local concentration of growth factors at specific tissues, PRF promotes tissue regeneration. PRF has been frequently used in combination with bone graft materials to reduce healing times and promote bone regeneration during maxillofacial surgery. However, its benefits during muscle repair and recovery are less well-documented. Here, we perform a narrative review on PRF therapies and muscle injuries to ascertain its beneficial effects. We reviewed the factors that contribute to the biological activity of PRF and the published pre-clinical and clinical evidence to support its emerging use in musculoskeletal therapy. We include in vitro studies, in vivo animal studies and clinical articles highlighting both the success and failures of PRF treatment. PRF can promote the healing process when used in a range of orthopaedic and sports-related injuries. These include cartilage repair, rotator cuff surgery and anterior cruciate ligament surgery. However, conflicting data for these benefits have been reported, most likely due to inconsistencies in both PRF preparation protocols and dosing regimens. Despite this, the literature generally supports the use of PRF as a beneficial adjuvant for a range of chronic muscle, tendon, bone or other soft tissue injuries. Further clinical trials to confirm these benefits require consistency in PRF preparation and the classification of a successful clinical outcome to fully harness its potential.

Effectiveness of Platelet-Rich Fibrin as an Adjunctive Material to Bone Graft in Maxillary Sinus Augmentation: A Meta-Analysis of Randomized Controlled Trails

Purpose

To date, it remains unknown whether the addition of platelet-rich fibrin (PRF) to bone grafts actually improves the effectiveness of maxillary sinus augmentation. This study aimed to perform a meta-analysis to evaluate the efficacy of PRF in sinus lift.

Materials and Methods

PubMed, Embase, and the Cochrane Library were searched. Randomized controlled studies were identified. The risk of bias was evaluated using the Cochrane Collaboration tool.

Results

Five RCTs were included in our meta-analysis. Clinical, radiographic, and histomorphometric outcomes were considered. No implant failure or graft failure was detected in all included studies within the follow-up period. The percentage of contact length between newly formed bone substitute and bone in the PRF group was lower but lacked statistical significance (3.90%, 95% CI, -2.91% to 10.71%). The percentages of new bone formation (-1.59%, 95% CI, -5.36% to 2.18%) and soft-tissue area (-3.73%, 95% CI, -10.11% to 2.66%) were higher in the PRF group but were not significantly different. The percentage of residual bone graft was not significant in either group (4.57%, 95% CI, 0% to 9.14%).

Conclusions

Within the limitations of this review, it was concluded that there were no statistical differences in survival rate, new bone formation, contact between newly formed bone and bone substitute, percentage of residual bone graft (BSV/TV), and soft-tissue area between the non-PRF and PRF groups. Current evidence supporting the necessity of adding PRF to bone graft in sinus augmentation is limited.

Evaluation of L-PRF combined with deproteinized bovine bone mineral for early implant placement after maxillary sinus augmentation: A randomized clinical trial

PURPOSE

To investigate the effectiveness of adding leukocyte and platelet-rich fibrin (L-PRF) to deproteinized bovine bone mineral (DBBM) for early implant placement after maxillary sinus augmentation.

MATERIALS AND METHODS

Twelve patients requiring two-stage bilateral maxillary sinus augmentation were enrolled to the study. The elevated sinus cavities were randomly grafted with DBBM + L-PRF (test) or DBBM alone (control) in a split-mouth design. Implants were placed in the augmented sites after 4 months in the test group and 8 months in the control group. Bone biopsies were collected during implant placement for histomorphometric evaluation. Resonance frequency analysis was performed immediately after implant placement and at implant loading in both groups. Cone-beam computed tomography was obtained preoperatively and postoperatively for evaluation of graft volume changes.

RESULTS

Both procedures were effective for maxillary sinus augmentation. Cone-beam computed tomography analysis did not reveal differences in graft volume between test and control group at any of the evaluated time points (P > .05). Histological evaluation demonstrated increased percentage of newly formed bone for the test group (44.58% ± 13.9%) compared to the control group (30.02% ± 8.42%; P = .0087). The amount of residual graft in the control group was significantly higher (13.75% ± 9.99%) than in the test group (3.59 ± 4.22; P = .0111). Implant stability quotient (ISQ) immediately after implant placement was significantly higher in the control group (75.13 ± 5.69) compared to the test group (60.9 ± 9.35; P = .0003). The ISQ values at loading did not differ between the groups (P = .8587). Implant survival rate was 100% for both groups.

CONCLUSION

The addition of L-PRF to the DBBM into the maxillary sinus allowed early implant placement (4 months) with increased new bone formation than DBBM alone after 8 months of healing.

Radiographic comparison of density and height of posterior maxillary bone after open sinus lift surgery with and without PRF

Background

Expansion of maxillary sinus towards the alveolar crest due to tooth loss or horizontal‒vertical resorption of the alveolar bone decreases the available bone for the placement of dental implants in the posterior maxilla. The method suggested for placing implants with a standard length is the use of sinus lift surgery with autogenous bone graft or bone substitute materials. The aim of the present research, with split-mouth design, was radiographic comparison of the density and height of the posterior of maxillary bone after open sinus lift procedure with and without PRF.

Materials and Methods.

In this split-mouth clinical trial, 14 patients were evaluated, with complete or partial bilateral edentulism of the upper jaw. In each case, for the sinus lift surgery of the test side, PRF was used, while in the sinus lift surgery of the other side of the same patient no graft materials were used. After six months and before the second surgery, CBCT was used to evaluate bone density and height.

Results

All the 41 implants were osseointegrated and were clinically stable. The bone height was 1.42 mm higher in the PRF group than the group without PRF, which was statistically significant. The mean density of the bone formed around the dental implants in the PRF group was 52.85 units higher than that of the group without PRF, which was statistically significant.

Conclusion

Using PRF in sinus lift surgery might enhance the quantity and quality of bone formation.

Biological activation of bone grafts using injectable platelet-rich fibrin

Platelet-rich fibrin (PRF) is gaining acceptance as a bioactive surgical additive in regenerative dentistry. However, PRF has only been available in gel or membrane form and is not suitable for injection. Recently, however, a liquid, injectable PRF has been introduced. This paper introduces the concept of injectable PRF and discusses its applications for biologic activation of bone grafts.

Sinus floor elevation with platelet-rich fibrin alone: A Clinical retrospective study of 1-7 years

Background

Several sinus floor elevation procedures for implant placement have been introduced. The present study aimed to evaluate the implants placed with Platelet-rich fibrin (PRF) alone in atrophic posterior maxillae and survival rates and the potential factors associated with implant loss.

Material and Methods

This retrospective study evaluated 71 implants in 34 patients after 1-7 years' follow-up time. Statistical models were used to determine the implant survival and the potential factors associated with loss.

Results

Overall, 7 implants were lost, and the cumulative survival rate at 7 years by implant-based and patient-bases analyses were 85.5% and 85.7%, respectively. The mean residual bone height (RBH) was 4.26 mm. The implant survival rate was significantly lower at RBH < 4 mm than RBH ≥ 4 mm.

Conclusions

This retrospective study showed that sinus floor elevation with PRF alone could be applied in cases of lower RBH. However, it should be carefully performed in cases of RBH < 4 mm before surgery. Key words:Platelet-rich fibrin, dental implant, sinus augmentation, retrospective study.

Abundant proteins in platelet-rich fibrin and their potential contribution to wound healing: An explorative proteomics study and review of the literature

Background/purpose

It is well-known that diverse types of blood proteins contribute to healing process via different mechanisms. Presence and potential involvements of blood-derived abundant proteins in the platelet-rich fibrin (PRF) to its regenerative capacity have not been sufficiently emphasized in the literature. The aim of this paper was to analyze the abundant proteome content of PRF and summarize previously reported effects of identified proteins on wound healing via a literature review.

Materials and methods

The PRF samples obtained from non-smoking, systemically healthy volunteers were subjected to 2D gel electrophoresis after extracting the proteins from fibrin matrices. All matching spots were excised from the gels and identified by MALDI TOF/TOF MS/MS analysis. A literature review was conducted to reveal possible contributions of identified proteins to wound healing.

Results

Totally, thirty-five blood proteins were commonly identified among all studied samples. These proteins included serine protease inhibitors, such as alpha-1-antitrypsin, alpha-1-antichymotrypsin, alpha-1-acid glycoprotein, inter-alpha-trypsin-inhibitor, protease C1 inhibitor, and complement proteins. In addition, abundant presence of immunoglobulin G was observed. The abundance of albumin, haptoglobin, ceruloplasmin vitronectin, fetuin-A, ficolin-3 and transthyretin was also detected.

Conclusion

The results of this study indicated that PRF abundantly contains blood-origin actors which were previously reported for their direct contribution to wound healing. Further studies exploring the protein content of PRF are needed to reveal its undisclosed potential roles in the healing process.

Maxillary Sinus Floor Augmentation to Enable One-Stage Implant Placement by Using Bovine Bone Substitute and Platelet-Rich Fibrin

Nowadays it is possible to perform an optimal implant placement and to achieve a good long-term prognosis for an implant-borne prosthesis in the grafted posterior maxilla. This study evaluates the efficiency of one-stage piezosurgery by using as graft material a combination of particulate bovine bone substitutes with platelet-rich fibrin to achieve sinus lift. We included in this study 14 cases of one-stage sinus lift surgeries during which we placed 30 standard implants. The mean vertical bone height gain was 10.12 mm six months after surgery, and the mean postoperative follow-up time was 43.79 months. There were no major complications during or after surgery, and all implants are in use. Therefore, it can be concluded that one-stage sinus piezosurgery using particulate bovine bone substitutes and platelet-rich fibrin can be applied as a predictable and effective technique in the treatment of the posterior edentulous maxilla ensuring 4-5 mm vertical bone height.

Autologous liquid platelet rich fibrin: A novel drug delivery system

There is currently widespread interest within the biomaterial field to locally deliver biomolecules for bone and cartilage regeneration. Substantial work to date has focused on the potential role of these biomolecules during the healing process, and the carrier system utilized is a key factor in their effectiveness. Platelet rich fibrin (PRF) is a naturally derived fibrin scaffold that is easily obtained from peripheral blood following centrifugation. Slower centrifugation speeds have led to the commercialization of a liquid formulation (liquid-PRF) resulting in an upper plasma layer composed of liquid fibrinogen/thrombin prior to clot formation that remains in its liquid phase for approximately 15 min until injected into bodily tissues. Herein, we introduce the use of liquid PRF as an advanced local delivery system for small and large biomolecules. Potential target molecules including large (growth factors/cytokines and morphogenetic/angiogenic factors), as well as small (antibiotics, peptides, gene therapy and anti-osteoporotic) molecules are considered potential candidates for enhanced bone/cartilage tissue regeneration. Furthermore, liquid-PRF is introduced as a potential carrier system for various cell types and nano-sized particles that are capable of limiting/by-passing the immune system and minimizing potential foreign body reactions within host tissues following injection.

STATEMENT OF SIGNIFICANCE

There is currently widespread interest within the biomaterial field to locally deliver biomolecules for bone and cartilage regeneration. This review article focuses on the use of a liquid version of platelet rich fibrin (PRF) composed of liquid fibrinogen/thrombin as a drug delivery system. Herein, we introduce the use of liquid PRF as an advanced local delivery system for small and large biomolecules including growth factors, cytokines and morphogenetic/angiogenic factors, as well as antibiotics, peptides, gene therapy and anti-osteoporotic molecules as potential candidates for enhanced bone/cartilage tissue regeneration.

Early Placement of Dental Implants in Maxillary Sinus Grafted With Leukocyte and Platelet-Rich Fibrin and Deproteinized Bovine Bone Mineral

This case report aimed to describe the effects of leukocyte and platelet-rich fibrin (L-PRF) associated with demineralized bovine bone mineral (DBBM) and absorbable collagen membrane (CM) on bone regeneration in maxillary sinus augmentation. A 59-year-old male patient was referred to the Department of Periodontology for implant rehabilitation of his edentulous upper jaw. The treatment plan involved maxillary sinus augmentation followed by implant installations. A split-mouth design was employed in which the right maxillary sinus was filled using L-PRF, DBBM, and CM; the left side was filled with DBBM and CM. After 4 and 8 months postoperatively, 2 dental implants were installed in each of the right and left maxillary sinuses. Cone-beam computerized tomography (CBCT) was taken before and after sinus augmentation for evaluation of tridimensional bone volume alterations. Bone biopsies were harvested from the implant sites for histomorphometric evaluation. Resonance frequency analysis was employed immediately after implant placement and before prosthetic rehabilitation for evaluation of implant stability. Implants were loaded 10 months after sinus augmentation. CBCT analysis showed a higher resorption rate in the right side of the maxillary sinus (L-PRF + DBBM) compared to the left side (22.25% and 8.95%, respectively). Implant stability quotients were above 68 in all time-points for both groups. Histomorphometric analysis showed a high amount of newly formed bone when L-PRF was used compared with DBBM alone (2 118 102 and 975 535 mm³, respectively). Taken together, both techniques were effective for maxillary sinus augmentation, however the addition of L-PRF to the graft allowed early implant placement and accelerated bone healing in the conditions studied.

Direct Maxillary Sinus Floor Augmentation for Simultaneous Dental Implant Placement

Aim:

The present study was done to evaluate the efficacy of platelet-rich fibrin (PRF) with bovine bone graft (Bio-Oss™) in direct sinus augmentation for simultaneously dental implant placement.

Materials and Methods:

The study included 14 patients who fulfill the inclusion criteria, among them 10 were male and 4 were female with PRF with Bio-Oss™. For each patient, bone level was assessed preoperatively and postoperatively after 1, 6, and 12 months with a panoramic X-ray and radiovisiography to evaluate the vertical bone height from the shoulder of the implant to the most apical end.

Results:

The outcome of the sinus lift and the implants placed was evaluated periodically at 1, 6, and 12 months postoperatively. All the patients underwent two-stage procedures. At the end of 20^th week, implants were exposed; radiological parameters were assessed again for implant integration, and prosthetic rehabilitation was started after 2 weeks and it was completed by the end of 24 weeks (6 months postoperatively). Twelve months postoperatively, the endosinus bone gain noted was 7 mm, which indicated the use of PRF with bovine bone graft as a reliable filling material during simultaneous sinus lift and implantation.

Conclusion:

PRF with bone graft (Bio-Oss) is used as an augmentation material after direct maxillary sinus lift, and the resulting bone formation was adequate for placement of dental implant.

Efficacy of platelet concentrates in bone healing: A systematic review on animal studies - Part B: Large-size animal models

In the presence of large bone defects, delayed bone union, or nonunion and fractures, bone reconstruction may be necessary. Different strategies have been employed to enhance bone healing among which the use of autologous platelet concentrates (APCs). Due to the high content of platelets and platelet-derived bioactive molecules (e.g., growth factors, antimicrobial peptides), they are promising candidates to enhance bone healing. However, both preclinical and clinical studies produced contrasting results, mainly due to a high heterogeneity in study design, objectives, techniques adopted, and outcomes assessed. The aim of the present systematic review was to evaluate the efficacy of APCs in animal models of bone regeneration, considering the possible factors that might affect the outcome. An electronic search was performed on MEDLINE and Scopus databases. Comparative animal studies with a minimum follow up of 2 weeks, at least five subjects per group and using APCs for regeneration of bone defects were included. Articles underwent risk of bias assessment and quality evaluation. Fifty studies performed on six animal species (rat, rabbit, dog, sheep, goat, mini-pig) were included. The present part of the review considers studies performed on small ruminants, dogs, and mini-pigs (14 articles). The majority of the studies were considered at low risk of bias. In general, APCs' adjunct positively affected bone regeneration. Animal species, platelet and growth factors concentration, type of bone defect and of platelet concentrate used seemed to influence their efficacy in bone healing. However, sound conclusions were not drawn since too few studies for each large-size animal model were included. In addition, characterization of APCs' content was performed only in a few studies. Further studies with a standardized protocol including characterization of the final products will provide useful information for translating the results to clinical application of APCs in bone surgery.

Clinical outcome of alveolar ridge augmentation with individualized CAD-CAM-produced titanium mesh

Background

The augmentation of the jaw has been and continues to be a sophisticated therapy in implantology. Modern CAD-CAM technologies lead to revival of old and established augmentation techniques such as the use of titanium mesh (TM) for bone augmentation. The aim of this retrospective study was to evaluate the clinical outcome of an individualized CAD-CAM-produced TM based on the CT/DVT-DICOM data of the patients for the first time.

Methods

In 17 patients, 21 different regions were augmented with an individualized CAD-CAM-produced TM (Yxoss CBR®, Filderstadt, Germany). For the augmentation, a mixture of autologous bone and deproteinized bovine bone mineral (DBBM) or autologous bone alone was used. Reentry with explantation of the TM and simultaneous implantation of 44 implants were performed after 6 months. Preoperative and 6-month postoperative cone beam computed tomographies (CBCT) were performed to measure the gained bone height.

Results

The success rate for the bone grafting procedure was 100%. Thirty-three percent of cases presented an exposure of the TM during the healing period. However, premature removal of these exposed meshes was not necessary. Exposure rate in augmentations performed with mid-crestal incisions was higher than in augmentations performed with a modified poncho incision (45.5 vs. 20%, p = 0.221). In addition, exposure rates in the maxilla were significantly higher than in the mandible (66.7 vs. 8.3%, p = 0.009). Gender, smoking, periodontal disease, gingiva type, used augmentation material, and used membrane had no significant influence on the exposure rate (p > 0.05). The mean vertical augmentation was 6.5 ± 1.7 mm, and the mean horizontal augmentation was 5.5 ± 1.9 mm. Implant survival rate after a mean follow-up of 12 ± 6 months after reentry was 100%.

Conclusion

Within the limits of the retrospective character of this study, this study shows for the first time that individualized CAD-CAM TM provide a sufficient and safe augmentation technique, especially for vertical and combined defects. However, the soft tissue handling for sufficient mesh covering remains one of the most critical steps using this technique.

Use of platelet-rich fibrin in regenerative dentistry: a systematic review

OBJECTIVES

Research across many fields of medicine now points towards the clinical advantages of combining regenerative procedures with platelet-rich fibrin (PRF). This systematic review aimed to gather the extensive number of articles published to date on PRF in the dental field to better understand the clinical procedures where PRF may be utilized to enhance tissue/bone formation.

MATERIALS AND METHODS

Manuscripts were searched systematically until May 2016 and separated into the following categories: intrabony and furcation defect regeneration, extraction socket management, sinus lifting procedures, gingival recession treatment, and guided bone regeneration (GBR) including horizontal/vertical bone augmentation procedures. Only human randomized clinical trials were included for assessment.

RESULTS

In total, 35 articles were selected and divided accordingly (kappa = 0.94). Overall, the use of PRF has been most investigated in periodontology for the treatment of periodontal intrabony defects and gingival recessions where the majority of studies have demonstrated favorable results in soft tissue management and repair. Little to no randomized clinical trials were found for extraction socket management although PRF has been shown to significantly decrease by tenfold dry sockets of third molars. Very little to no data was available directly investigating the effects of PRF on new bone formation in GBR, horizontal/vertical bone augmentation procedures, treatment of peri-implantitis, and sinus lifting procedures.

CONCLUSIONS

Much investigation now supports the use of PRF for periodontal and soft tissue repair. Despite this, there remains a lack of well-conducted studies demonstrating convincingly the role of PRF during hard tissue bone regeneration. Future human randomized clinical studies evaluating the use of PRF on bone formation thus remain necessary.

CLINICAL RELEVANCE

PRF was shown to improve soft tissue generation and limit dimensional changes post-extraction, with little available data to date supporting its use in GBR.

Volumetric changes of grafted volumes and the Schneiderian membrane after transcrestal and lateral sinus floor elevation procedures: A clinical, pilot study

AIM

To investigate the influence of various surgical techniques for sinus augmentation on the volumetric changes of graft, membrane and the post-operative discomfort.

MATERIALS AND METHODS

Eighteen patients in need of bilateral sinus floor elevation (SFE) were assigned to lateral SFE, transcrestal SFE and intralift procedures. CBCT images taken at baseline, 1 week and 6 weeks were analysed for volumetric changes in graft and Schneiderian membrane. Questionnaires were used to analyse post-op discomfort.

RESULTS

The overall average graft volume obtained after 1 week was 1.87 cm³ (range 0.12-4.72 cm³ ). Volumes decreased after 6 weeks to an overall mean volume of 1.33 cm³ (range 0.10-4.29 cm³ - average decrease of 27.6%). After 6 weeks, the amount of graft volume decreased in every treatment option, ranging from -23.13% for the tSFE, over -24.55% for the lSFE, to -33.71% for the IL. Although all treatment options correspond in an increase in Schneiderian membrane volume, no statistically significant correlation between this increase and loss of graft volume could be obtained for all treatments (p = 0.97).

CONCLUSION

All SFE techniques provided sufficient graft volume for implant treatment. All techniques provoke a partially transient swelling of the Schneiderian membrane. All techniques resulted in a decrease in graft volume after 6 weeks; however, no significant differences were obtained between treatments. Furthermore, no statistical significant correlation between the post-operative swelling of the Schneiderian membrane and reduction in graft volume at 6 weeks could be obtained.

Sinus Augmentation by Platelet-Rich Fibrin Alone: A Report of Two Cases with Histological Examinations

In sinus floor augmentation of an atrophic posterior maxilla, platelet-rich fibrin (PRF) has been used as a graft material. We herein report two cases with histological evaluations of PRF after the surgery. The first case was a 28-year-old female with an atrophic right posterior maxilla who was treated with sinus floor augmentation and simultaneous implant placement using PRF as the sole graft material in our hospital. Twenty-four months after surgery, the implant was unfortunately removed because of occlusal overloading by parafunctional habits. During implant replacement, a tissue sample was obtained from the site of augmentation with PRF and was evaluated histologically. The second case was a 58-year-old man with severe alveolar atrophy of the right maxilla who underwent lateral sinus augmentation using only PRF in a two-stage procedure in our hospital. Samples were obtained at the second-stage surgery and histological examinations were performed. As a result, new bone formation was confirmed histologically in both cases. Our findings show that the use of PRF as a graft material during sinus floor augmentation induces natural bone regeneration.