Leukocyte- and platelet-rich fibrin as graft material improves microRNA-21 expression and decreases oxidative stress in the calvarial defects of diabetic rabbits

Effect of Ethyl-Cyanoacrylate and Platelet-Rich Fibrin on Fresh Sockets of Rabbits Subjected to Anticoagulant Therapy

Objectives: There are no studies related to the use of PRF associated with cyanoacrylates in fresh post-extraction sockets. Thus, the aim of this study was to assess the effect of ethyl-cyanoacrylate combined with PRF in fresh sockets of rabbits subjected to anticoagulant therapy. Methods: Twelve adults rabbits were selected and premedicated with heparin 1 week before surgery to induce and simulate anticoagulant therapy. Upper and lower first premolars on the right side were extracted and then were divided into four groups of three animals each, with the groups distributed according to the type of intervention in the sockets (n = 6): (1) clot and suture (control); (2) PRF and suture; (3) clot and ethyl-cyanoacrylate; (4) PRF and ethyl-cyanoacrylate. At 12 weeks, the animals were sacrificed and the sockets were analyzed histologically and quantitatively. Total bone area, inflammation infiltrate, and adhesive remnants were assessed. Results: No remnants of adhesive were found in the samples. Groups 1 and 2 showed the highest bone area (G1 = 37.87% ± 17.86; G2 = 30.31 ± 9.36) with significant differences to those treated with ethyl-cyanoacrylate adhesive (G3 = 26.6% ± 11.82; G4 = 24.29% ± 6.25). Conclusions: The groups that used ethyl-cyanoacrylate as a closure method in sockets exhibited less bone area than the groups that used sutures. Both groups that used PRF as therapy did not show a significant improvement in bone healing at 12 weeks compared with the clot groups.

The Potential of miR-21 in Stem Cell Differentiation and its Application in Tissue Engineering and Regenerative Medicine

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two important types of non-coding RNAs that are not translated into protein. These molecules can regulate various biological processes, including stem cell differentiation and self-renewal. One of the first known miRNAs in mammals is miR-21. Cancer-related studies have shown that this miRNA has proto-oncogene activity and is elevated in cancers. However, it is confirmed that miR-21 inhibits stem cell pluripotency and self-renewal and induces differentiation by targeting various genes. Regenerative medicine is a field of medical science that tries to regenerate and repair damaged tissues. Various studies have shown that miR-21 plays an essential role in regenerative medicine by affecting stem cell proliferation and differentiation. In this review, we will discuss the function of miR-21 in regenerative medicine of the liver, nerve, spinal cord, wound, bone, and dental tissues. In addition, the function of natural compounds and lncRNAs will be analyzed as potential regulators of miR-21 expression in regenerative medicine.

microRNAs Are Abundant and Stable in Platelet-Rich Fibrin and Other Autologous Blood Products of Canines

Various microRNAs (miRNAs) present in autologous blood products of canines have not been studied recently. We aimed to elucidate the existence of miRNAs in platelet-rich fibrin (PRF) and the stability of canine autologous blood products under various storage conditions. Total RNAs were isolated from PRF and other autologous blood products following newly adapted protocols used in commercial kits for plasma and tissue samples. Quantitative real-time polymerase chain reaction analysis (qPCR) was used to detect miRNAs in autologous blood products. The miR-16, miR-21, miR-155, and miR-146a were abundant in PRF and other autologous blood products of canines. Furthermore, we found they could maintain stability under protracted freezing temperatures of -30 °C for at least one month. Our findings revealed that PRF might be a stable resource for various canine miRNAs.

Clinical Perspectives of Non-Coding RNA in Oral Inflammatory Diseases and Neuropathic Pain: A Narrative Review

Non-coding RNAs (ncRNAs) represent a research hotspot by playing a key role in epigenetic and transcriptional regulation of diverse biological functions and due to their involvement in different diseases, including oral inflammatory diseases. Based on ncRNAs’ suitability for salivary biomarkers and their involvement in neuropathic pain and tissue regeneration signaling pathways, the present narrative review aims to highlight the potential clinical applications of ncRNAs in oral inflammatory diseases, with an emphasis on salivary diagnostics, regenerative dentistry, and precision medicine for neuropathic orofacial pain.

Salivary VEGF and post-extraction wound healing in type 2 diabetic immediate denture wearers

OBJECTIVE

Oral wound healing in healthy could be promoted by VEGF in saliva, and immediate denture wearing, but data in type 2 diabetes are lacking. Aims were to investigate the timeline of extraction wound healing in diabetic participants wearing immediate dentures and its correlation to salivary VEGF, as well as to examine the impact of the palatal plate on tissue VEGF during palatal wound healing in rat diabetic model.

MATERIAL AND METHODS

Healthy (42) and type 2 diabetic (36) denture wearers, candidates for teeth extractions were included. Extraction wound healing was followed via measurements of socket closure, gingival hyperaemia, pain and presence of necrosis on 3^rd, 7^th, 14^th and on 21^st-day post-extraction. Salivary VEGF was measured before and on the 3^rd and 21^st day after the extraction. In streptozotocin-induced diabetic (30) as well as non-diabetic rats (30), tissue VEGF was measured in palatal wounds healing under or without a palatal plate.

RESULTS

Type 2 diabetic prosthetic patients exhibit delayed socket closure, with pronounced hyperaemia, pain and necrosis. Salivary VEGF is increased in diabetes and positively correlates to socket closure while negatively with pain on 21^st day after the extraction. Palatal incision induced VEGF increase in non-diabetic and diabetic, but less pronounced in diabetic rats. Wound healing under the palatal plate exhibit higher tissue VEGF.

CONCLUSION

Type 2 diabetes-induced increase in salivary VEGF may mitigate diabetes-induced detrimental effects on extraction wound healing. Lack of adequate tissue VEGF response to injury may underly dysregulation of diabetic oral wound healing.

Plasma Rich in Growth Factors in the Treatment of Endodontic Periapical Lesions in Adult Patients: A Narrative Review

Platelet concentrates have been widely used in regenerative medicine, including endodontics. The aim of this manuscript was to assess critically the efficacy of PRF in the treatment of endodontic periapical lesions in adult patients on the basis of the literature. The PICO approach was used to properly develop literature search strategies. The PubMed database was analyzed with the keywords: "((PRP) OR (PRF) OR (PRGF) OR (CGF)) AND (endodontic) AND ((treatment) OR (therapy))". After screening of 155 results, 14 articles were included in this review. Different types of platelet concentrates are able to stimulate the processes of proliferation and differentiation of mesenchymal stem cells. Platelet rich fibrin (PRF) releases growth factors for at least 7 days at the application site. Growth factors and released cytokines stimulate the activity of osteoblasts. Moreover, the release of growth factors accelerates tissue regeneration by increasing the migration of fibroblasts. It was not possible to assess the efficacy of PRF supplementation in the treatment of endodontic periapical lesions in permanent, mature teeth with closed apexes, due to the lack of well-designed scientific research. Further studies are needed to analyze the effect of PRF on the healing processes in the periapical region.

Features of a simvastatin-loaded multi-layered co-electrospun barrier membrane for guided bone regeneration

A novel tri-layer membrane consisting of polycaprolactone (PCL) fibrous sheets and structured nanofibers with a gelatin (Gt) shell and a simvastatin-containing PCL core (PCL-Gt/PCL-simvastatin membrane) was prepared. The soft external layer comprised of Gt/PCL-simvastatin, the external layer of PCL and the middle layer of both microfilaments, interwoven together. The membrane was designed to promote osteoinduction and act as a barrier against cells but not against water and molecules in order to promote guided bone regeneration. The structure of the membrane was characterized by scanning electronic microscopy. The in vitro release rates of simvastatin over 32 days were determined by high-performance liquid chromatography. For in vitro biological assays, bone marrow mesenchymal stem cells and human fibroblasts were cultured on the different surfaces of the membrane. Cell adhesion, proliferation, distribution, and differentiation were examined. For in vivo testing, cranial defects were created in rabbits to assess the amount of new bone formed for each membrane. The results revealed that membranes with multi-layered structures showed good cell viability and effective osteoinductive and barrier properties. These results suggest that the novel multi-layered PCL-Gt/PCL-simvastatin membranes have great potential for bone tissue engineering.

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

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

Buccal bone regeneration combined with piezocision in adult orthodontic patients: Clinical, 3D radiographic, and patient-reported outcomes

OBJECTIVE

Assess the clinical effects, 3D radiographic results and patient-reported outcome measures (PROMs) of buccal bone regeneration combined with piezocision.

METHODS

Ten patients presenting roots prominence with a thin buccal bone thickness or buccal bone dehiscence in the lower front region were enrolled. Patients received orthodontic treatment assisted by piezocison which was combined with a buccal alveolar bone regeneration using a tunneling approach. A comparison between pre- and post-treatment alveolar bone measurements based on CBCT was performed. Periodontal parameters such as recession scores and root resorption were recorded before and after treatment. The PROMs were also investigated.

RESULTS

An overall significant buccal bone gain of 2.7 ± 2.7% was found after the treatment. The apical region reached the highest gain of 8.9 ± 5.5% whereas the most coronal region showed no significant increase of the bone envelope (1.2 ± 2.7%). No adverse event such as the appearance of recession or root resorption were observed. However, in 2 patients, the biomaterial was not properly integrated and seemed to be encapsulated. The pain level and the paracetamol consumption were equivalent to those after the placement of the orthodontic appliance except on the day of the surgery.

CONCLUSIONS

Within the limitation of this study, piezocision combined with buccal bone regeneration using a tunneling technique seems to be effective to augment bone and did not lead to gingival recession. However, in 2 cases the biomaterial seemed encapsulated, and therefore the predictability of the integration of the material can be questioned. ClinicalTrials.gov registration : NCT03655938.