Platelet-rich plasma in sinus augmentation procedures: a systematic literature review: Part II

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.

Complications in sinus lifting procedures: Classification and management

Open and closed sinus lifting procedures are predictable methods to augment the bone needed for appropriate implant placement in the posterior maxilla in cases where available bone is limited. However, these techniques may give rise to complications and associated comorbidities. In the case of open sinus lifting, perforation of the Schneiderian membrane during osteotomy is the most common complication, with an incidence rate of around 20%-25%. Apart from those complications associated with oral surgery in general (such as swelling or hematoma), there are specific complications of open sinus lifting procedures that may arise less frequently (chronic rhinosinusitis, hemorrhage, or ostium blockage by overfilling) but which may nevertheless compromise the viability of the graft and/or the implants and cause substantial discomfort to the patient. Closed sinus lifting is a less invasive approach that allows transcrestal placement of the implants in cases where there is sufficient residual bone height. However, it may also be associated with specific complications, including membrane perforation, benign paroxysmal positional vertigo, and implant displacement to the sinus cavity. New technologies have been proposed to reduce these complications and comorbidities associated with conventional sinus lifting procedures, such as the use of piezoelectric devices and hydraulic sinus lift or reamer burs. The evidence supporting their effectiveness and safety, however, is still lacking. A detailed medical history together with a thorough radiographic and clinical examination are essential prior to any kind of bone regenerative augmentation involving the maxillary sinus. Moreover, it is recommended to employ the most appropriate surgical technique for the specific characteristics of the case and, at the same time, accommodating the experience and skills of the surgeon.

Moulvi SM. Assessment of knowledge, awareness, and perception of platelet-rich plasma among oral surgeons

Aim:

The current survey was conducted to assess the knowledge and awareness of platelet-rich plasma (PRP) among oral surgeons in the state of Tamil Nadu.

Methodology:

The cross-sectional questionnaire survey was conducted among oral surgeons in the state of Tamil Nadu. The self-administered questions related to knowledge and awareness of PRP were collected from 500 participants. The statistical analysis was done using Statistical Package for the Social Sciences SPSS (V 22.0). The frequency distribution was computed.

Results:

This survey exposed that 454 (90.4%) respondents had knowledge and awareness about the role of PRP. Forty (7.0%) were knowledgeable regarding the PRP treatment. Four hundred and fifty-four (90.6%) had aware about the usage of PRP procedures in oral surgery.

Conclusion:

The current study's findings indicate that the oral surgeons were aware of PRP as an auxiliary therapeutic technique for wound healing and maturation.

Will stem cells from fat and growth factors from blood bring new hope to female patients with reproductive disorders?

Female reproductive system disorders (FRSD) with or without infertility are prevalent women's health problems with a variety of treatment approaches including surgery and hormone therapy. It currently considering to sub-branch of regenerative medicine including stem cells or growth factors injection-based delivery treatment might be improved female reproductive health life. The most common products used for these patients treatment are autologous cell or platelet-based products from patients, including platelet-rich plasma, plasma rich in growth factor, platelet-rich fibrin, and stromal vascular fraction. In this review, we discuss each of the above products used in treatment of FRSD and critically evaluate the clinical outcome.

Platelet rich plasma in oral and maxillofacial surgery from the perspective of composition

The application of platelet-rich plasma (PRP) in oral and maxillofacial surgery has been thoroughly studied in the last two decades. Currently, different types of PRP are applied in the clinical practice, being the presence or absence of leukocytes one of the classification criteria. However, there is poor evidence assessing the influence of the PRP composition in their efficacy. In this context, the aim of this narrative review is to compile the existing evidence covering the efficacy of PRP in oral and maxillofacial surgery, starting from a systematic literature search and to qualitatively describe the efficacy outcomes from the composition perspective. According to the results of this review, the application of PRP in oral and maxillofacial surgery is a potential strategy to improve soft- and hard-tissue regeneration, observing differences in the efficacy of PRP depending on its composition and the studied application. P-PRP (the absence of leukocytes) has been more consistent in achieving beneficial effects in alveolar ridge preservation, management of post-extraction complications, bone augmentation and temporomandibular joint disorders. For that, the composition and methodology used to prepare the PRP should be a critical point when evaluating the efficacy of PRP.

Preclinical and Clinical Applications of Biomaterials in the Enhancement of Wound Healing in Oral Surgery: An Overview of the Available Reviews

Oral surgery has undergone dramatic developments in recent years due to the use of biomaterials. The aim of the present review is to provide a general overview of the current biomaterials used in oral surgery and to comprehensively outline their impact on post-operative wound healing. A search in Medline was performed, including hand searching. Combinations of searching terms and several criteria were applied for study identification, selection, and inclusion. The literature was searched for reviews published up to July 2020. Reviews evaluating the clinical and histological effects of biomaterials on post-operative wound healing in oral surgical procedures were included. Review selection was performed by two independent reviewers. Disagreements were resolved by a third reviewer, and 41 reviews were included in the final selection. The selected papers covered a wide range of biomaterials such as stem cells, bone grafts, and growth factors. Bioengineering and biomaterials development represent one of the most promising perspectives for the future of oral surgery. In particular, stem cells and growth factors are polarizing the focus of this ever-evolving field, continuously improving standard surgical techniques, and granting access to new approaches.

Long-Term Influence of Platelet-Rich Plasma (PRP) on Dental Implants after Maxillary Augmentation: Implant Survival and Success Rates

The atrophic maxilla often requires bone augmentation before implant placement to ensure long-term implant success. A previous prospective clinical trial examined the use of platelet-rich plasma (PRP) during maxillary augmentation. The short-term results showed no positive effect of PRP. The aim of this study was to evaluate the same patient collective of the previous study regarding the PRP long-term impact on the survival and success of dental implants. Fifty-three patients from the previous study diagnosed with maxillary atrophy and augmented with autologous bone grafts from the iliac crest and dental implants, were included in this study. Treatment was carried out on both sides in 34 patients with a split-mouth-design in which one randomly chosen side was treated additionally with PRP, the other side was the control-side. Nineteen patients were treated only on one side and were assigned to the PRP-or the control group randomly. Implant follow-up of the patients from the previous study was performed after an average time of 13 years. Implant success was evaluated using two different success criteria. Thitry-seven patients (25 women and 12 men) were investigated in this study. Seventeen patients (12 female, 5 male) were included in the PRP group, while 20 patients (13 female, 7 male) participated in the control group. A total of 210 implants were inserted. Of these, 102 implants (48.57%) were placed in the PRP group and 108 implants (51.42%) in the control group. Out of 102 investigated implants in the PRP group, 6 were removed (survival rate 94.1%). While two of the 108 implants in the control group were loss (survival rate 98.1%). In the PRP group, the cumulative probability of survival after 15.1 years was 94.1% and in the control group, was 98.1%, with no significant difference between the two groups. Higher significant difference for the control group was found in the cumulative success probability using Albrektson criteria (p = 0.05). Positive impact of PRP on long-term implant survival and success could not be found.

Long-Term Influence of Platelet-Rich Plasma (PRP) on Dental Implants after Maxillary Augmentation: Retrospective Clinical and Radiological Outcomes of a Randomized Controlled Clinical Trial

: The long-term clinical and radiological outcomes of dental implants inserted in augmented bone treated with platelet-rich plasma (PRP) has not been well addressed in the literature yet. This study is based on a collection of patients from a randomized controlled trial (RCT) that did not report any short-term positive effects of PRP on bone healing after sinus lift surgery using autologous iliac crest bone graft. This study aimed to evaluate the long-term impact of PRP regarding clinical and radiological outcomes on the inserted implants in the previous RCT. For this evaluation, we considered the following variables: plaque index, probing depth, bleeding index, mobility grade, Periotest® values, and radiological bone loss. Out of 53 patients (n = 306 implants) included in the previous study we were able to reinvestigate 37 patients (n = 210 implants) in two centers (31 in Giessen, Germany and 6 in Erlangen, Germany). Clinical and radiographic parameters suggested overall healthy conditions of the peri-implant tissue. The PRP-group and the control group did not differ significantly in the majority of the parameters. The overall evaluation showed that result data of the PRP-group was inferior to the control group in 64 percent of the evaluated parameters. The present study cannot provide evidence of a positive effect of PRP on the long-term implant clinical and radiological outcomes. In fact, a tendency towards inferior long-term results in the PRP-group was detected without reaching a significant threshold. Further controlled trials need to be conducted to investigate this correlation.

Efficacy of platelet-rich plasma for non-transfusion use: Overview of systematic reviews

INTRODUCTION

Platelet-rich plasma (PRP) is a blood component therapy with a supraphysiological concentration of platelets derived from allogenic or, more commonly, autologous blood. PRP has been used in different non-transfusion indications because of its role in the promotion of tissue repair and healing, in fields such as Traumatology, Dermatology and Dentistry.

OBJECTIVE

To provide a synthesis of the efficacy of PRP for different clinical situations.

METHODS

Systematic searches were carried out in MEDLINE, Embase, Cochrane Library and LILACS in July 2018 to identify systematic reviews (SRs) of randomized clinical trials (RCTs) focusing on PRP for non-transfusion use. Two authors independently screened all retrieved references in two stages (titles and abstracts at a first stage and full texts at a second stage). The methodological quality of SRs that met the eligibility criteria was appraised by AMSTAR 2. Conclusions were based on the most recent SRs with highest quality.

RESULTS

One thousand two hundred and forty references were retrieved. After checking the inclusion criteria, 29 SRs of RCTs related to three different fields (wound care, Orthopedics and Dentistry) were included. The results suggest the benefit of PRP for different clinical situations, such as diabetic wounds, acute lesions of musculoskeletal system, rotator cuff lesions, tendinopathies, knee and hip osteoarthritis, total knee arthroplasty, allogenic bone graft for dental implants and periodontal intrabony defects.

CONCLUSION

There is low to moderate quality evidence supporting the efficacy of PRP for specific clinical situations. The low quality of the evidence limits the certainty of these findings. Well-planned and well-conducted RCTs are still needed to further assess the efficacy of PRP.

Plasma rich in growth factors (PRGF) in intraoral bone grafting procedures: A systematic review

PURPOSE

This systematic review aimed at assessing the effects of PRGF in new bone formation, soft tissue healing and post-operative pain and swelling in sites that underwent ridge preservation, ridge augmentation and maxillary sinus augmentation procedures.

MATERIALS AND METHODS

A comprehensive literature search employing seven databases was conducted by two independent reviewers. Only randomized and non-randomized controlled clinical trials using PRGF alone or in combination with bone grafting materials were selected.

RESULTS

Overall, 919 studies were identified, of which a total of 8 articles were included in the qualitative analysis. Two of the selected studies reported on ridge preservation, one on ridge augmentation and five on maxillary sinus augmentation. Positive results were recorded for soft tissue healing and post-operative pain and swelling following these procedures. However, outcomes of PRGF on new bone formation post extraction and on maxillary sinus augmentation when combined with other biomaterials were conflicting. Meta-analysis could not be conducted for any variables due to the heterogeneity of selected studies.

CONCLUSION

Limited evidence exists on the effects of PRGF in different intraoral bone grafting procedures, with some benefit reported on soft tissue healing and post-operative symptomatology. As this platelet concentrate is commonly used in clinical practice, further research is needed to fully assess its clinical indications and effectiveness.

Platelet-Rich Plasma, Hydroxyapatite, and Chitosan in the Bone and Cartilaginous Regeneration of Femoral Trochlea in Rabbits: Clinical, Radiographic, and Histomorphometric Evaluations

The aim of this study was to evaluate the trochlear bone and cartilaginous regeneration of rabbits using the association of PRP, chitosan, and hydroxyapatite. Hole was made in rabbit troches, one hole in each animal remained empty (group C), and one was filled by a combination of PRP, chitosan, and hydroxyapatite (group T). Clinical-orthopedic, radiographic, and histomorphometric evaluations were performed. Clinical-orthopedic evaluation showed lameness of two members of the T group and one member of group C. The radiographic evaluation showed that the T group showed absence of subchondral bone reaction (33%). The presence of moderate subchondral bone reaction was more frequently reported in group C with 67%. Microscopic evaluation revealed a presence of tissue neoformation, composed of connective tissue. Microscopic findings were similar in both groups, with a difference in the amount of neoformed tissue being perceptible, which was confirmed after the morphometric analysis, which revealed a significant difference in the quantity of newly formed tissue at the bone/cartilage/implant interface. The composite base of the association of chitosan, hydroxyapatite, and platelet-rich plasma favored bone and cartilage healing.

Maxillary Sinus Augmentation for Dental Implant Rehabilitation of the Edentulous Ridge: A Comprehensive Overview of Systematic Reviews

OBJECTIVES

The objective of this systemic review was to perform a comprehensive overview of systematic reviews and meta-analyses of the maxillary sinus augmentation procedure for implant rehabilitation in humans. The following were evaluated in this overview: (1) anatomic variables affecting sinus augmentation, (2) histomorphometric analysis of the grafted sinus, (3) volumetric changes after sinus grafting, and (4) implant survival beyond 1 year.

MATERIAL AND METHODS

Electronic databases were searched for systematic reviews and meta-analyses of implant-related sinus augmentation published from 1976 to September 2015. The studies selected must identify itself as a systemic review or meta-analysis in the title or abstract and must pertain to sinus augmentation.

RESULTS

Thirty-three publications fulfilled the review criteria. The AMSTAR ratings for the 33 chosen reviews scored greater than 3 of 11, with 8 reviews scoring greater or equal to 8 of 11.

CONCLUSION

The outcome of this overview suggested that the following will increase the success of sinus augmentation and survival of implants placed in the grafted sinus: (1) the use of barrier membranes over the lateral window when using a lateral approach to graft the sinus, (2) the use of particulate autogenous bone with or without other substitute graft materials, (3) sinus augmentation without the use of grafting materials may be considered provided that the space between the sinus membrane and floor can be maintained, (4) the use of rough-surfaced implants, (5) simultaneous implant placement with residual bone height greater than 4 mm, and (6) the cessation of smoking.

Adjunctive Platelet-Rich Plasma (PRP) in Infrabony Regenerative Treatment: A Systematic Review and RCT's Meta-Analysis

Background and Objective

The purpose of this study was to highlight the clinical performance of platelet-rich plasma (PRP) used as an adjunctive tool for regeneration in infrabony periodontal defects using different biomaterials or performing different surgical flap approaches. Comparative evaluation of main clinical outcomes as probing pocket depth reduction, clinical attachment gain, and recession reduction with and without the use of PRP has been analysed.

Materials and Methods

According to the focused question, an electronic and hand searching has been performed up to December 2016. From a batch of 73 articles, the selection strategy and Jadad quality assessment led us to include 15 studies for the meta-analysis.

Results

Despite the high heterogeneity found and the lack of complete data regarding the selected clinical outcomes, a comparative analysis has been possible by the categorization of used biomaterials and surgical flap approaches. This method led us to observe the best performance of grafts with the use of adjunctive PRP in CAL gain and PPD reduction. No difference has been outlined with a specific surgical flap.

Conclusions

Although PRP is considered a cheap and patient's derived growth factor, the not conclusive data reported would suggest that its use in addition to bone substitutes could be of some clinical benefit in the regenerative treatment of infrabony defects.

Clinical Relevance

This systematic review was intended to sort out the huge controversial debate in the field about the possible use of PRP in regenerative surgery in infrabony defect. The clinical relevance of using blood-borne growth factors to conventional procedures is effective as these could determine a better performance and outcomes despite the surgical approach adopted and limit the use of additional biomaterials for the blood clot stabilization.

Application of platelet-rich plasma with stem cells in bone and periodontal tissue engineering

Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors (GFs), it makes stem cells the ideal agents for bone regeneration. Furthermore, platelet-rich plasma (PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future.

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.

Histologic, histomorphometric, and cone-beam computerized tomography analyses of calcium sulfate and platelet-rich plasma in socket preservation: a pilot study

OBJECTIVES

To assess dimensional changes and histologic/histomorphometric aspects of grafted sockets using either calcium sulfate-platelet-rich plasma (CS-PRP) or CS alone in socket preservation procedure.

STUDY DESIGN

Twelve subjects with single nonmolar teeth underwent atraumatic extraction. Six sockets received CS grafts and 6 sockets received CS-PRP grafts. Cone-beam computerized tomography scans taken immediately after extraction and 4 months after surgery were used to measure vertical and horizontal dimensional changes. Histologic and histomorphometric analyses of grafted sites were performed at 4 months after surgery. Intergroup changes were compared using Mann-Whitney U test.

RESULTS

CS group demonstrated 18.6% horizontal resorption as compared with 9.2% in CS-PRP group. Resorption for buccal height (BH) (14%) and palatal/lingual height (PH) (13.7%) in CS group was nearly 3 times more than resorption in BH (5%) and PH (4.6%) for CS-PRP group. Mineralized bone component in CS-PRP group (11.19% ± 6.59%) was significantly more than CS group (1.51% ± 2.86%) (P = 0.01).

CONCLUSION

CS-PRP-grafted sites demonstrated higher mineralized bone content than CS-grafted sites.

Effectiveness of platelet-rich plasma as an adjunctive material to bone graft: a systematic review and meta-analysis of randomized controlled clinical trials

The use of platelet-rich plasma (PRP) has become a strategic therapy in tissue regeneration medicine. PRP represents a good source of growth factors. Due to this property, it has been considered a reliable adjunctive material in bone augmentation procedures, such as the sinus lift technique. The aim of this review was to assess the scientific evidence on the effectiveness of PRP as an adjunctive material in the sinus floor elevation technique. The following databases were searched for relevant published studies: Medline, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, Science Direct, ISI Web of Knowledge, and SCOPUS. Only randomized controlled clinical trials comparing a group receiving PRP as an adjunctive material to a control group without PRP, involving adult human subjects (age >18 years) with no systemic disease, were included. Of the studies identified, only one reported a significant difference in bone augmentation in favour of the adjunctive use of PRP, while four studies did not find any significant difference. None of the studies included reported a significant difference in the implant survival rate. Further randomized clinical trials are needed to clarify the effectiveness of adjunctive PRP.

Use of platelet-rich plasma in deep second- and third-degree burns

Unfortunately burns are a common occurrence, leading to scarring or death. Platelet-rich plasma (PRP) contains many growth factors that can accelerate wound healing. We analyzed the use of PRP in deep second-degree (dSD), deep second-degree associated with diabetes mellitus (dSDD), and third-degree (TD) burns in rats. Sixty syngeneic rats divided into three groups (dSD, dSDD, and TD) were burned, half receiving topical PRP and half being used as control; 10 additional rats per group were used for PRP preparation. On day 21, the animals were sacrificed and skin biopsies were collected. dSD and dSDD wounds treated with PRP showed faster wound closure, reduction in CD31-, CD68-, CD163-, MPO-, and in TGF-β-positive cells, and an increase in MMP2-positive cells. The neo-epidermis was thinner in the control of both the dSD and dSDD groups and granulation tissue was less reduced in the control of both the dSDD and TD groups. These results indicate that PRP can accelerate the healing process in dSD and dSDD, but not in TD burns.

Platelet preparations in dentistry: How? Why? Where? When?

The aim of this article is to review the outcomes of platelet preparations in dentistry. A structured electronic search discovered 348 articles, which described the use of autologous platelet concentrates with a relevance to clinical dentistry. Among these articles, 220 articles investigated platelet rich plasma, 99 investigated platelet rich fibrin, 22 investigated plasma rich in growth factors and 7 investigated the use of concentrated growth factors. Several studies reported beneficial treament outcomes in terms of enhanced bone and soft tissue regeneration.

Bone marrow aspirate concentrate and platelet-rich plasma enhanced bone healing in distraction osteogenesis of the tibia

BACKGROUND

During lower limb lengthening, poor bone regeneration is a devastating complication. Several local or systemic applications have been used to promote osteogenesis, and biologic stimulations are gaining attention, but their utility has not been proven in this setting.

QUESTIONS/PURPOSES

In patients undergoing bilateral tibial lengthening, we compared those receiving an osteotomy site injection of autologous bone marrow aspirate concentrate (BMAC) plus platelet-rich plasma (PRP) with those not receiving such an injection in terms of external fixator index (time in external fixation divided by amount of lengthening), full weightbearing index (time until a patient was permitted to do full weightbearing divided by amount of lengthening), four cortical healing indexes (time until each cortical union divided by amount of lengthening), and callus shape and type.

METHODS

Twenty-two patients (44 tibias) undergoing bilateral tibial lengthening enrolled in this randomized trial. Two patients were excluded, one due to insufficient radiographic evaluation and one who was lost to followup, leaving 20 patients (40 segments) for inclusion. Ten patients (20 segments) received BMAC combined with PRP injection (treatment group) and 10 patients (20 segments) received no injection (control group). All patients underwent stature lengthening for familial short stature with the lengthening over nail technique. Autologous BMAC combined with PRP was injected at the tibial osteotomy site at the end of the index surgery. Mean distraction rates were similar between groups (0.75 mm/day in the treatment group versus 0.72 mm/day in the control group; p = 0.24). Full weightbearing was permitted when we observed radiographic evidence of healing at two cortices; this assessment was made by the surgeon who was blinded to the treatment each patient received. Minimum followup was 24 months (mean, 28 months; range, 24-34 months).

RESULTS

There was no difference in mean external fixator index between groups. However, mean cortical healing indexes (anterior/posterior/medial/lateral) were 1.14/0.81/0.96/0.88 months/cm in the treatment group and 1.47/1.26/1.42/1.22 months/cm in the control group (all p < 0.001), showing faster healing in the treatment group at each cortex. Full weightbearing was permitted earlier in the treatment group than in the control group (index: 0.99 months/cm and 1.38 months/cm, respectively, p < 0.001). Callus shape and type were not different between groups.

CONCLUSIONS

Autologous BMAC combined with PRP injection at the osteotomy site helped improve bone healing in distraction osteogenesis of the tibia, although the effect size was small.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Experimental study of the effect of autologous platelet-rich plasma on the early phases of osteoinduction by allogenic demineralized bone matrix

PURPOSE

To evaluate the effect of autologous platelet-rich plasma (PRP) on the early phases of osteoinduction by allogenic demineralized bone matrix (DBM) in rabbit intramuscular positions.

MATERIALS AND METHODS

Allogenic DBM was produced from bones of 3 healthy rabbits. In each of 6 experimental animals, 0.3 mL autologous PRP was prepared and 2 muscle pouches were created, where 250 mg DBM + PRP (experimental sites) and 250 mg DBM without PRP (control sites) were randomly implanted. Animals were euthanized 3 weeks postoperatively.

RESULTS

Histologic examination revealed uneventful healing in all cases, whereas remineralization of the periphery of the bone graft particles was a constant finding. In both control and experimental sites, fibroblasts and other mesenchymal cells (probably osteoprogenitor cells and preosteoblasts) were observed. The main histological difference was the recolonization of the empty lacunae of the bone graft particles by osteocytes at the control sites. The degradation of the graft at the control sites was statistically significantly quicker, although a statistically significant difference regarding the amount of the newly formed fibrous connective tissue was not observed.

CONCLUSION

The present study demonstrated that in this experimental model, the addition of PRP to DBM had a negative effect on the early phases of osteoinduction at 3 weeks of observation.

Clinical applications of cell-based approaches in alveolar bone augmentation: a systematic review

BACKGROUND

Cell-based approaches, utilizing adult mesenchymal stem cells (MSCs), are reported to overcome the limitations of conventional bone augmentation procedures.

PURPOSE

The study aims to systematically review the available evidence on the characteristics and clinical effectiveness of cell-based ridge augmentation, socket preservation, and sinus-floor augmentation, compared to current evidence-based methods in human adult patients.

MATERIALS AND METHODS

MEDLINE, EMBASE, and CENTRAL databases were searched for related literature. Both observational and experimental studies reporting outcomes of "tissue engineered" or "cell-based" augmentation in ≥5 adult patients alone, or in comparison with non-cell-based (conventional) augmentation methods, were eligible for inclusion. Primary outcome was histomorphometric analysis of new bone formation. Effectiveness of cell-based augmentation was evaluated based on outcomes of controlled studies.

RESULTS

Twenty-seven eligible studies were identified. Of these, 15 included a control group (8 randomized controlled trials [RCTs]), and were judged to be at a moderate-to-high risk of bias. Most studies reported the combined use of cultured autologous MSCs with an osteoconductive bone substitute (BS) scaffold. Iliac bone marrow and mandibular periosteum were frequently reported sources of MSCs. In vitro culture of MSCs took between 12 days and 1.5 months. A range of autogenous, allogeneic, xenogeneic, and alloplastic scaffolds was identified. Bovine bone mineral scaffold was frequently reported with favorable outcomes, while polylactic-polyglycolic acid copolymer (PLGA) scaffold resulted in graft failure in three studies. The combination of MSCs and BS resulted in outcomes similar to autogenous bone (AB) and BS. Three RCTs and one controlled trial reported significantly greater bone formation in cell-based than conventionally grafted sites after 3 to 8 months.

CONCLUSIONS

Based on limited controlled evidence at a moderate-to-high risk of bias, cell-based approaches are comparable, if not superior, to current evidence-based bone grafting methods, with a significant advantage of avoiding AB harvesting. Future clinical trials should additionally evaluate patient-based outcomes and the time-/cost-effectiveness of these approaches.

Platelet-rich plasma (PRP) in dental and oral surgery: from the wound healing to bone regeneration

Platelet-rich plasma (PRP) is a new approach to tissue regeneration and it is becoming a valuable adjunct to promote healing in many procedures in dental and oral surgery, especially in aging patients. PRP derives from the centrifugation of the patient's own blood and it contains growth factors that influence wound healing, thereby playing an important role in tissue repairing mechanisms. The use of PRP in surgical practice could have beneficial outcomes, reducing bleeding and enhancing soft tissue healing and bone regeneration. Studies conducted on humans have yielded promising results regarding the application of PRP to many dental and oral surgical procedures (i.e. tooth extractions, periodontal surgery, implant surgery). The use of PRP has also been proposed in the management of bisphosphonate-related osteonecrosis of the jaw (BRONJ) with the aim of enhancing wound healing and bone maturation. The aims of this narrative review are: i) to describe the different uses of PRP in dental surgery (tooth extractions and periodontal surgery) and oral surgery (soft tissues and bone tissue surgery, implant surgery and BRONJ surgery); and ii) to discuss its efficacy, efficiency and risk/benefit ratio. This review suggests that the use of PRP in the alveolar socket after tooth extractions is certainly capable of improving soft tissue healing and positively influencing bone regeneration but the latter effect seems to decrease a few days after the extraction. PRP has produced better results in periodontal therapy in association with other materials than when it is used alone. Promising results have also been obtained in implant surgery, when PRP was used in isolation as a coating material. The combination of necrotic bone curettage and PRP application seem to be encouraging for the treatment of refractory BRONJ, as it has proven successful outcomes with minimal invasivity. Since PRP is free from potential risks for patients, not difficult to obtain and use, it can be employed as a valid adjunct in many procedures in oral and dental surgery. However, further RCTs are required to support this evidence.

Use of plasma rich in growth factor for schneiderian membrane management during maxillary sinus augmentation procedure

The aim of this pilot study was to present a novel technique for the management of the Schneiderian membrane during maxillary sinus lift surgery using plasma rich in growth factors (PRGF). Eight maxillary sinuses were augmented in 8 patients. Two small perforations of the Schneiderian membrane occurred during the lifting procedure, which were solved using the PRGF clot before grafting the site with PRGF and anorganic bovine bone. With the exception of 1 patient who experienced pain following an acute sinus infection after 3 days of uneventful healing, the patients' postoperative quality of life was generally good. The most common complication (50% of cases) was hematoma, which disappeared after 1 week. Despite the limitations of this study concerning the sample size and the study design, the use of PRGF may be helpful in reducing complications following sinus lift surgery. More well-designed studies, with larger sample size, are needed to validate this protocol.

Stem cells in dentistry--Part II: Clinical applications

New technologies that facilitate solid alveolar ridge augmentation are receiving considerable attention in the field of prosthodontics because of the growing requirement for esthetic and functional reconstruction by dental implant treatments. Recently, several studies have demonstrated potential advantages for stem-cell-based therapies in regenerative treatments. Mesenchymal stem/stromal cells (MSCs) are now an excellent candidate for tissue replacement therapies, and tissue engineering approaches and chair-side cellular grafting approaches using autologous MSCs represent the clinical state of the art for stem-cell-based alveolar bone regeneration. Basic studies have revealed that crosstalk between implanted donor cells and recipient immune cells plays a key role in determining clinical success that may involve the recently observed immunomodulatory properties of MSCs. Part II of this review first overviews progress in regenerative dentistry to consider the implications of the stem cell technology in dentistry and then highlights cutting-edge stem-cell-based alveolar bone regenerative therapies. Factors that affect stem-cell-based bone regeneration as related to the local immune response are then discussed. Additionally, pre-clinical stem cell studies for the regeneration of teeth and other oral organs as well as possible applications of MSC-based immunotherapy in dentistry are outlined. Finally, the marketing of stem cell technology in dental stem cell banks with a view toward future regenerative therapies is introduced.

[Contribution of platelet concentrates to oral and maxillo-facial surgery]

INTRODUCTION

We evaluated the clinical contribution of platelet concentrates to oral and maxillo-facial surgery.

MATERIAL AND METHOD

This bibliographic research was made using the PubMed MeSH database with the following keywords: "platelet rich fibrin" (PRF), "platelet rich plasma" (PRP), "bone", "facial bone", "dental implant", and "blood platelet". The research was made without any date or language limitation since English summaries were available. All summaries were read to evaluate the relevance of the article. Only original articles and case reports were considered. The articles were classified as "in vitro studies", "animal experiments", or "clinical studies". The research was stopped on March 22, 2012.

RESULTS

One hundred and sixty-nine articles were validated after excluding irrelevant articles, reviews, technical notes, and articles without English or French summaries. Seventeen were in vitro studies, 61 animal experiments, and 91 clinical studies. One hundred and ten complete articles were read to complete summary data. The data of in vitro studies univocally supports of using platelet concentrates. The data from animal experiment studies was less consensual and the validity of animal models was contested. The disparity of clinical study designs and the lack of rigorous methodology did not allow clearly determining platelet concentrate benefits for oral and maxillo-facial surgery.

DISCUSSION

PRF or PRP clinical benefit has not been clearly demonstrated yet. French regulations relative to their use should be clarified.

In vivo comparison of the bone regeneration capability of human bone marrow concentrates vs. platelet-rich plasma

BACKGROUND

Bone marrow aspirate concentrate (BMAC) including high densities of stem cells and progenitor cells may possess a stronger bone regenerative capability compared with Platelet-rich plasma (PRP), which contains enriched growth factors. The objective of this study was to evaluate the effects of human BMAC and PRP in combination with β-tricalcium phosphate (β-TCP) on promoting initial bone augmentation in an immunodeficient mouse model.

METHODOLOGY/PRINCIPAL FINDINGS

BMAC and PRP were concentrated with an automated blood separator from the bone marrow and peripheral blood aspirates. β-TCP particles were employed as a scaffold to carry cells. After cell counting and FACS characterization, three groups of nude mice (BMAC+TCP, PRP+TCP, and a TCP control) were implanted with graft materials for onlay placement on the cranium. Samples were harvested after 4 weeks, and serial sections were prepared. We observed the new bone on light microscopy and performed histomorphometric analysis. After centrifugation, the concentrations of nucleated cells and platelets in BMAC were increased by factors of 2.8 ± 0.8 and 5.3 ± 2.4, respectively, whereas leucocytes and platelets in PRP were increased by factors of 4.1 ± 1.8 and 4.4 ± 1.9, respectively. The concentrations of CD34-, CD271-, CD90-, CD105-, and CD146-positive cells were markedly increased in both BMAC and PRP. The percentage of new bone in the BMAC group (7.6 ± 3.9%) and the PRP group (7.2 ± 3.8%) were significantly higher than that of TCP group (2.7 ± 1.4%). Significantly more bone cells in the new bone occurred in sites transplanted with BMAC (552 ± 257) and PRP (491 ± 211) compared to TCP alone (187 ± 94). But the difference between the treatment groups was not significant.

CONCLUSIONS/SIGNIFICANCE

Both human BMACs and PRP may provide therapeutic benefits in bone tissue engineering applications. These fractions possess a similar ability to enhance early-phase bone regeneration.

Platelet gel: applications in dental regenerative surgery

BACKGROUND

Platelet growth factors obtained from platelet-rich plasma (PRP) are used in prosthetic and periodontal regenerative therapy in dentistry. Increased microvascular proliferation in the first 20 days is followed by enhanced osteoblast activity and immature osteoid formation within 3-6 weeks, improving the quality and quantity of newly formed bone tissue. The aim of this study was to evaluate, through three-dimensional X-ray monitoring, the amount of bone obtained after bone regeneration treatment with platelet gel from autologous PRP.

MATERIALS AND METHODS

Patients eligible for regenerative treatment of atrophic alveolar bone of the maxilla or mandible were studied. The patients' autologous whole blood was collected at the Department of Immunology and Transfusion of San Matteo Hospital for the preparation of platelet gel. The bone at the treated sites was analysed prior to and 4 months after the treatment using the three-dimensional X-ray system Galileos.

RESULTS

Over a period of 6 years, 133 patients were treated: 304 implants were inserted and there were five cases of failure. The regenerated bone area consisted of histologically immature osteoid tissue composed of thin trabeculae of vital bone and nuclei of osteocytes, associated with fibro-connective tissue.

DISCUSSION

This co-operative trial between the Transfusion Centre, for standardised production and validation of the platelet gel, and the Dental Surgery room for its application showed that the technique appears effective and safe. Although difficulties were encountered because of the small sample size and the inability to carry out long-term histological controls, the use of small amounts of PRP (5-10%) combined with autologous bone (15-20%) and alloplastic material appears to reduce the need for bone grafting.

Effect of autologous growth factors in maxillary sinus augmentation: a systematic review

PURPOSE

The aim of the present study was to systematically evaluate the effect of autogenous platelet concentrates on the clinical and histomorphometric outcomes of maxillary sinus augmentation.

MATERIALS AND METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched using a combination of specific search terms. Furthermore, a hand searching of the relevant journals and of the bibliographies of reviews was performed. Prospective comparative clinical studies were included. Implant survival and histomorphometric outcomes were evaluated.

RESULTS

Twelve studies were included. Four hundred forty-five sinus floor augmentation procedures were considered. No difference in implant survival was reported between test and control groups. Six studies reported a beneficial effect of platelet concentrates based on histomorphometric outcomes, while another six studies found no significant effect. A large heterogeneity was found regarding study design, surgical techniques, graft materials, clinical and histomorphometric outcome variables, and methods for preparing platelet concentrates. Favorable effects on soft tissue healing and postoperative discomfort reduction were often reported but not quantified.

CONCLUSIONS

A clear advantage of platelet concentrates could not be evidenced. Standardization in the experimental design is needed in order to detect the true effect of platelet concentrates in maxillary sinus augmentation procedure, especially regarding postoperative quality of life.

A review on endogenous regenerative technology in periodontal regenerative medicine

Periodontitis is a globally prevalent inflammatory disease that causes the destruction of the tooth-supporting apparatus and potentially leads to tooth loss. Currently, the methods to reconstitute lost periodontal structures (i.e. alveolar bone, periodontal ligament, and root cementum) have relied on conventional mechanical, anti-infective modalities followed by a range of regenerative procedures such as guided tissue regeneration, the use of bone replacement grafts and exogenous growth factors (GFs), and recently developed tissue engineering technologies. However, all current or emerging paradigms have either been shown to have limited and variable outcomes or have yet to be developed for clinical use. To accelerate clinical translation, there is an ongoing need to develop therapeutics based on endogenous regenerative technology (ERT), which can stimulate latent self-repair mechanisms in patients and harness the host's innate capacity for regeneration. ERT in periodontics applies the patient's own regenerative 'tools', i.e. patient-derived GFs and fibrin scaffolds, sometimes in association with commercialized products (e.g. Emdogain and Bio-Oss), to create a material niche in an injured site where the progenitor/stem cells from neighboring tissues can be recruited for in situ periodontal regeneration. The choice of materials and the design of implantable devices influence therapeutic potential and the number and invasiveness of the associated clinical procedures. The interplay and optimization of each niche component involved in ERT are particularly important to comprehend how to make the desired cell response safe and effective for therapeutics. In this review, the emerging opportunities and challenges of ERT that avoid the ex vivo culture of autologous cells are addressed in the context of new approaches for engineering or regeneration of functional periodontal tissues by exploiting the use of platelet-rich products and its associated formulations as key endogenous resources for future clinical management of periodontal tissue defects.