Effect of Platelet-Rich-Plasma (PRP) and Implant Surface Topography on Implant Stability and Bone

Autologous Platelet Concentrates (APCs) for Hard Tissue Regeneration in Oral Implantology, Sinus Floor Elevation, Peri-Implantitis, Socket Preservation, and Medication-Related Osteonecrosis of the Jaw (MRONJ): A Literature Review

Simple Summary

Autologous platelet concentrates with high growth factor levels are used in many fields of dentistry. In recent years, the critical role of blood-derived materials in bone and soft tissue engineering has become apparent. After tooth extraction, the alveolar bone is exposed to progressive bone resorption, which can lead to difficulties in implant placement. Hence, many studies have demonstrated that APCs have the potential for soft tissue and bone regeneration. Furthermore, no inflammatory reactions occur, and they may be used alone or in combination with bone grafts, promoting bone growth and maturation. Moreover, the released growth factors and the presence of fibrin structures can induce osteogenesis. This review aims to provide information regarding the applications, indications, advantages, and disadvantages of three APC techniques in hard tissue regeneration.

Abstract

Over recent years, the usage of autologous platelet concentrates (APCs) has risen in hard tissue regeneration and oral implantology. The purpose of the present review is to offer an overview of the use of three APC techniques in dentistry: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factor (CGF). A narrative summary of articles published between January 2011 and April 2022 is provided. The PubMed, Cochrane Library, Scopus, and Embase databases were used to conduct the search. The following keywords were used in the preliminary: “VEGF”, “TGF-b1”, “PRP”, “PRF”, “CGF”, AND “sinus augmentation” OR “implants” OR “peri-implantitis” OR “socket preservation” OR “MRONJ”. A total of 82 articles was finally included. The review then takes into account the application of the three techniques in different areas of treatment—including oral implantology, sinus floor elevation, peri-implantitis, socket preservation, and medication-related osteonecrosis of the jaw (MRONJ)—as well as their advantages and disadvantages.

Effects of platelet concentrates on implant stability and marginal bone loss: a systematic review and meta-analysis

Background

Osseointegration is essential for the success and stability of implants. Platelet concentrates were reported to enhance osseointegration and improve implant stability. The purpose of this review is to systematically analyze the effects of platelet concentrates on implant stability and marginal bone loss.

Methods

Two researchers independently performed searches in the following databases (last searched on 21 July 2021): MEDLINE (PubMed), Cochrane Library, EMBASE, and Web of Science. In addition, a manual search was carried out on references of relevant reviews and initially included studies. All randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on the application of platelet concentrates in the implant surgery procedure were included. The risk of bias of RCTs and CCTs were assessed with a revised Cochrane risk of bias tool for randomized trials (RoB 2.0) and the risk of bias in non-randomized studies—of interventions (ROBINS-I) tool, respectively. Meta-analyses on implant stability and marginal bone loss were conducted. Researchers used mean difference or standardized mean difference as the effect size and calculated the 95% confidence interval. In addition, subgroup analysis was performed based on the following factors: type of platelet concentrates, method of application, and study design.

Results

Fourteen studies with 284 participants and 588 implants were included in the final analysis. 11 studies reported implant stability and 5 studies reported marginal bone level or marginal bone loss. 3 studies had high risk of bias. The meta-analysis results showed that platelet concentrates can significantly increase implant stability at 1 week (6 studies, 302 implants, MD 4.26, 95% CI 2.03–6.49, P < 0.001) and 4 weeks (8 studies, 373 implants, MD 0.67, 95% CI 0.46–0.88, P < 0.001) after insertion, significantly reduced marginal bone loss at 3 months after insertion (4 studies, 95 implants, mesial: MD − 0.33, 95% CI − 0.46 to − 0.20, P < 0.001; distal: MD − 0.38, 95% CI − 0.54 to − 0.22, P < 0.001). However, the improvement of implant stability at 12 weeks after insertion was limited (P = 0.10). Subgroup analysis showed that PRP did not significantly improve implant stability at 1 week and 4 weeks after insertion (P = 0.38, P = 0.17). Platelet concentrates only placed in the implant sites did not significantly improve implant stability at 1 week after insertion (P = 0.20).

Conclusions

Platelet concentrates can significantly improve implant stability and reduce marginal bone loss in the short term. Large-scale studies with long follow‐up periods are required to explore their long-term effects and compare effects of different types.

Trial registration

This study was registered on PROSPERO, with the Registration Number being CRD42021270214.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01929-x.

Effect of Platelet-Rich Plasma on Bone Healing in Immediate Implants Analyzed by Cone Beam Computerized Tomography: A Randomized Controlled Trial

The possibility of platelet-rich plasma (PRP) on the improvement of bone and adjacent tissue recovery has previously been validated. However, there is insufficient data supporting the use of platelet-rich plasma to improve the healing of bone and adjacent tissues around an implant in the oral cavity. The purpose of this randomized controlled trial was to observe the effect of platelet-rich plasma (PRP) concentrate on marginal bone loss and bone density around immediate implant placement using Cone Beam Computerized Tomography (CBCT). This clinical study was conducted over a period of six months on 12 subjects, who were equally categorized into two groups. Group I was the control, whereas the subjects in Group II received PRP therapy at the surgical site. All subjects were given a standard treatment with a single implant system (DIO UFII hybrid sandblasted acid-etched implants). Inserted implants were analyzed through CBCT, and records were registered at baseline, at the 12^th week before functional loading and the 26^th week after functional loading. The bone loss was calculated at the proximal (mesial and distal) side of the implant and bone density at baseline, 12^th week, and 26^th week after implant placement. SPSS version 23.0 was used for statistical analysis of data. The changes in bone levels were measured and compared between the two groups using the Mann-Whitney U test, with no significant difference. Bone density was analyzed by an independent sample t-test, p value ≤ 0.05 was considered statistically significant. Again, no significant difference in bone density was observed between both groups at all three instances. Therefore, it can be concluded that local injection of PRP after immediate implant placement did not show any decrease in marginal bone loss or improvement in bone density. This trial is registered with NCT04650763.

Platelet adhesion on commercially pure titanium plates in vitro III: effects of calcium phosphate-blasting on titanium plate biocompatibility

BACKGROUND

Platelet-rich plasma (PRP) is often used to improve surface biocompatibility. We previously found that platelets rapidly adhere to plain commercially pure titanium (cp-Ti) plates in the absence, but not in the presence, of plasma proteins. To further expand on these findings, in the present study, we switched titanium plates from a plain surface to a rough surface that is blasted with calcium phosphate (CaP) powder and then examined platelet adhesion and activation.

METHODS

Elemental distribution in CaP-blasted cp-Ti plates was analyzed using energy-dispersive X-ray spectroscopy. PRP samples prepared from anticoagulated blood samples of six healthy, non-smoking adult male donors were loaded on CaP-blasted cp-Ti plates for 1 h and fixed for examination of platelet morphology and visualization of PDGF-B and platelet surface markers (CD62P, CD63) using scanning electron microscopy and fluorescence microscopy. Plain SUS316L stainless steel plates used in injection needles were also examined for comparison.

RESULTS

Significant amounts of calcium and phosphate were detected on the CaP-blasted cp-Ti surface. Platelets rapidly adhered to this surface, leading to higher activation. Platelets also adhered to the plain stainless surface; however, the levels of adhesion and activation were much lower than those observed on the CaP-blasted cp-Ti plate.

CONCLUSIONS

The CaP-blasted cp-Ti surface efficiently entraps and activates platelets. Biomolecules released from the activated platelets could be retained by the fibrin matrix on the surface to facilitate regeneration of the surrounding tissues. Thus, PRP immersion could not only eliminate surface air bubbles but also improve the biocompatibility of the implant surface.

Biomimetic Aspects of Oral and Dentofacial Regeneration

Biomimetic materials for hard and soft tissues have advanced in the fields of tissue engineering and regenerative medicine in dentistry. To examine these recent advances, we searched Medline (OVID) with the key terms “biomimetics”, “biomaterials”, and “biomimicry” combined with MeSH terms for “dentistry” and limited the date of publication between 2010–2020. Over 500 articles were obtained under clinical trials, randomized clinical trials, metanalysis, and systematic reviews developed in the past 10 years in three major areas of dentistry: restorative, orofacial surgery, and periodontics. Clinical studies and systematic reviews along with hand-searched preclinical studies as potential therapies have been included. They support the proof-of-concept that novel treatments are in the pipeline towards ground-breaking clinical therapies for orofacial bone regeneration, tooth regeneration, repair of the oral mucosa, periodontal tissue engineering, and dental implants. Biomimicry enhances the clinical outcomes and calls for an interdisciplinary approach integrating medicine, bioengineering, biotechnology, and computational sciences to advance the current research to clinics. We conclude that dentistry has come a long way apropos of regenerative medicine; still, there are vast avenues to endeavour, seeking inspiration from other facets in biomedical research.

Platelet Adhesion on Commercially Pure Titanium Plates in Vitro II. Immunofluorescence Visualization of PDGF-B, TGFβ1, and PPARγ Released from Activated Adherent Platelets

Recent progress in the industrial development of dental implants has improved their surface bio-affinity, while clinical implantologists attempt to improve it through coating with various compounds, including platelet-rich plasma (PRP) in clinical settings. However, it is poorly understood how PRP acts on titanium surfaces. To validate this surface modification method and demonstrate how platelet-derived soluble biomolecules released from the activated adherent platelets act on plain, commercially pure-titanium (cp-Ti) plates, we evaluated the distribution of biomolecules by immunofluorescence. PPARγ, PDGF-B, and TGFβ1 were similarly released at immunofluorescence levels from activated adherent platelets, retained in the surrounding extra-platelet spaces for a while, and did not immediately diffuse away to distant spaces. Exogenously added CaCl₂ augmented release and retention of those biomolecules along with activation and aggregation. Taken together with our previous data regarding platelet adhesion, these findings suggest that especially when treated with CaCl₂, platelets immediately adhere on cp-Ti plates to release their stored biomolecules in the absence of plasma proteins and that these biomolecules do not diffuse away, but stay longer in extra-platelet spaces around the platelets by newly formed, immature fibrin fiber fragments. Consequently, these retained biomolecules are anticipated to cooperatively stabilize implants by stimulating alveolar bone regeneration and integration.

EVALUATION OF CENTRIFUGING REGIMES FOR THE PURPOSE OF OPTIMIZING THE PLATELET RICH PLASMA HARVESTING PROTOCOL

Aim: Based on the classical principles, to determine the optimal conditions for centrifugation, PRP harvesing (platelet-rich plasma). To conduct a quantitative assessment of the substrate obtained under different conditions of centrifugation. Materials and methods. Based on the basic principles of obtaining platelet-rich plasma (PRP) by centrifuging in containers with an anticoagulant followed by phase separation to obtain the final substrate, the efficiency of the technique under the conditions of single and double centrifugation as well as under different conditions of acceleration and centrifugation was evaluated. Blood for follow-up was collected from 20 healthy volunteers (11 men, 9 women) average 25.3±4.1 in syringes of LuerLock design with ACD-A anticoagulant solution, and centrifuged. Centrifugation was carried out under controlled conditions using a centrifuge with rotating bowls of the rotor. Centrifugation was performed at an acceleration of 100-400g in time intervals up to 20 minutes. Activation of the substrate was performed with calcium chloride solution. Quantitative evaluation of platelets of whole blood and the final substrate of PRP was carried out with a semi-automatic analyzer. Results. The obtained results demonstrate the maximum level of harvesting efficiency when performing double centrifugation in the 150g×15 min+250g×10 min mode. Subject to this centrifugation protocol, it is possible to obtain a substrate that complies with the standardized requirements for PRP. The maximum level of an increase in the number of platelets in the substrate in comparison with whole blood is determined at the level of ×4.36 with concentration (volume reduction) x5 in comparison with the volume of whole blood. Conclusions. This study demonstrated the advantage of double centrifuging modes over single modes. According to the results of the study, it was possible to determine the conditions for an optimal double-centrifugation mode (acceleration and duration), which allows us to achieve the most efficient concentration of the substrate.

The use of platelet-rich plasma to enhance the outcomes of implant therapy: A systematic review

Objective

To assess the effect of platelet‐rich plasma (PRP) on implant dentistry. The primary focused question was as follows: What are the clinical, histological, and radiographic outcomes of PRP administration for bone regeneration and implant therapy?

Methods

A literature search was conducted involving three databases: MEDLINE, EMBASE and Cochrane database followed by a hand search of relevant scientific journals. Human studies using PRP for bone regeneration and implant therapy were considered and articles published up to December 31, 2017 were included. Eligible studies were selected based on the inclusion criteria, and quality assessments were conducted.

Results

In total, out from the 9,497 titles meeting the original search criteria, 22 fulfilled the inclusion criteria and were chosen for data extraction. Among them were 15 randomized controlled trials (RCT) and seven controlled clinical trials (CCT). Overall, the risk of bias was moderate to high. A total of seven studies showed superior outcomes when PRP was added during sinus floor elevation and five showed no superior outcome. Three studies found a significant advantage of PRP for alveolar bone regeneration and another three studies for soft tissue healing. Three studies reported on beneficial effects of PRP directly during implant placement while another study failed to find significant differences. Due to the heterogeneity of study designs, no meta‐analysis could be performed.

Summary and Conclusions

Despite the lack of consistent evidence supporting the clinical benefit of PRP in healthy patients, PRP might have a positive effect on wound healing and bone regeneration in compromised patients.

Platelet adhesion on commercially pure titanium plates in vitro I: effects of plasma components and involvement of the von Willebrand factor and fibronectin

Background

Platelet-rich plasma (PRP) is widely used in regenerative dentistry. Furthermore, it is often applied in the pretreatment of titanium implants to improve their surface bioaffinity and initial stability. However, effects of PRP application on implant surface at cellular and molecular levels remain poorly understood. Therefore, we examined platelet adhesion on commercially pure titanium (cp-Ti) plates, with a particular focus on fibrinogen (FGN), von Willebrand factor (vWF), and fibronectin (FN), in the presence or absence of plasma components.

Methods

Citrated blood samples were obtained from six healthy male volunteers, and pure-PRP (P-PRP) and pure platelet suspensions in phosphate-buffered saline (PBS) were prepared. Platelet adhesion on cp-Ti plate surface was evaluated by phalloidin staining and tetrazolium dye assay. Distribution of FGN, vWF, FN, albumin, CD62P, and CD63 was examined by immunocytochemical analysis.

Results

Platelets in PBS suspensions rapidly and time-dependently adhered to cp-Ti plate surface, but this adhesion was substantially disturbed by the presence of plasma components. FGN was most preferably adsorbed regardless of the presence or absence of plasma components, while vWF and FN showed greater accumulation on platelet adhesion area.

Conclusions

Although FGN is rapidly and abundantly adsorbed on cp-Ti plate surface, vWF and FN function as major platelet adhesion molecules in citrated blood samples. After pretreatment with P-PRP, however, platelets adhered to cp-Ti much less efficiently. Therefore, P-PRP pretreatment might not directly contribute to surface functionalization, initial stabilization, and osseointegration of machined or similar types of implants.

Electronic supplementary material

The online version of this article (10.1186/s40729-019-0160-z) contains supplementary material, which is available to authorized users.

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.

Effect of Platelet Rich Fibrin (PRF) on Peri-implant Soft Tissue and Crestal Bone in One-Stage Implant Placement: A Randomized Controlled Trial

INTRODUCTION

The viability of Platelet Rich Fibrin (PRF) on enhancement of osseous and associated tissue healing has been substantiated well in literature. However, paucity in the applicability of PRF to enhance peri-implant healing in oral region is not well-corroborated.

PURPOSE

This prospective study evaluated the effect of Platelet PRF on peri-implant tissue response following one-stage implant placement with non-functional immediate provisionalization in maxillary anterior region.

MATERIALS AND METHODS

A Prospective, Randomized Controlled Trial (RCT) was conducted across 20 (15 male, 5 Female) systemically healthy subjects with maintainable oral hygiene. Subjects were broadly divided into two groups i.e. Study group (PRF group) and Control group (Non-PRF group). Twenty standard SLA- AB/AE (alumina oxide blasted/acid etched surface treated) tapered threaded dental implants were randomly placed with and without PRF and immediately provisionalized. The subjects were evaluated clinically and radiographically at baseline (at time of implant placement), one month and three month post-operatively for peri-implant soft tissue and crestal bone responses.

RESULTS

At 3 months, all implants remained osseointegrated. The mean marginal bone changes were observed from baseline to 3 months in both groups with lesser changes observed in PRF Group. No significant differences in probing depth and bleeding on probing were noted during follow-up.

CONCLUSION

Within the limitations of this study, PRF could be considered as a healing biomaterial with potential beneficial effect on peri-implant tissue and can be used as a therapeutic adjuvant in clinical scenario of one stage, single tooth implant placement procedure in maxillary anterior region.