Tag Archives: PRGF

Two case reports of vertical and horizontal augmentation with autogenous bone blocks; seven years follow-up

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By C. Ratiu, Simona Cavalu et al.

The aim of this work was to highlight the advantages of autogenous bone grafting combined with plasma rich in growth factors (PRGF) in order to improve healing and reduce dehiscence risks. Two clinical cases were presented, both with important (horizontal and vertical) bone loss: in the first case, bone augmentation was performed at the same time as tooth extraction with no surgery needed for reconstruction of dental papillae, keratinized and attached mucosa; in the second case, vertical augmentation was performed by placing the bone graft in contact with an uninfected tooth. In both cases, aesthetic outcomes were as desired at the completion of treatment and also satisfactory at seven years follow-up. Copyright C. Ratiu, Simona Cavalu et al.

Crown-root fracture and bone harvesting from chin. Copyright C. Ratiu, Simona Cavalu et al.
Wound closure and healing, 4 months after surgery. Copyright C. Ratiu, Simona Cavalu.
Implant placement, non-functional immediate restoration. Copyright C. Ratiu, Simona Cavalu et al.
Healing after 12 weeks, aesthetic result with zirconia restoration. Copyright C. Ratiu,
Simona Cavalu et al.
CBCT after 7 years. Copyright C. Ratiu, Simona Cavalu et al.

The bone collected from the chin is predominantly cortical, with a reduced spongy component, which affects the re-vascularization efficiency. Even though the mandibular bone has an increased density, which makes it optimal for implants’ osseointegration, its regenerative potential is reduced [1, 2]. Moreover, the reconstruction of the horizontal defect is more predictable than of the vertical ones, as there are more bone walls. Consequently, the source for the capillaries that will invade the graft is
larger. A more modern and better approach uses longitudinal sectioning of the bone block, thinning of the bone with a bone scraper and filling the gap between the bone graft and the recipient site with small bone particles; the bone graft is acting as a bone barrier against soft tissue penetration into the graft. Copyright C. Ratiu, Simona Cavalu et al.

(a,b) Interdental septum, buccal and palatal plate missing; (c) Bone harvested from chin, soaking in plasma rich in growth factors (PRGF). Copyright C. Ratiu, Simona Cavalu et al.
(a) Bone fixation on buccal plate, after graft splitting; (b) Bone fixation on palatal plate after graft splitting; (c) Gaps filled with cancellous bone. Copyright C. Ratiu, Simona Cavalu et al.
(a) Graft covered with fibrin membrane; (b) Wound closure after periosteum release; (c) Healing after six months. Copyright C. Ratiu, Simona Cavalu et al.
(a) Graft integration after six months; (b) Implant placement into the grafted bone; (c) Bone augmentation with bone obtained from the drill. Copyright C. Ratiu, Simona Cavalu et al.
(a) Graft covered with fibrin membrane; (b) Wound suture around the healing screw; c) Probing depth of about 2 mm. Copyright C. Ratiu, Simona Cavalu et al.
(a) Aesthetic result four months after the implant placement;
(b) Aesthetic result with lip retracted. Copyright C. Ratiu, Simona Cavalu et al.
a) Aesthetic outcome after
seven years follow-up; (b) Cone-beam
computed tomography (CBCT) after
seven years follow-up. Copyright C. Ratiu, Simona Cavalu et al.

In the second case, however, the implant was placed six months after grafting and significant resorption was noticed. Even though the graft was integrated in the first case, the risk for dehiscence was very high; a deep
incision was made for flap release that interested even the muscles fibers. A safer approach might be performing the bone graft procedure four weeks’ after tooth extraction healing, done along with PRGF placement into the alveolar socket. Deep sectioning of the muscles fibers most likely leads to soft tissue healing without surgery needed for keratinized and attached mucosa. In the second case, a safer approach might be the extraction of tooth 1.1. and bone grafting in the position of both central incisors; placing the grafted bone in contact with the root of a tooth is risky due to the possible contamination, which can lead to graft infection and loss . Copyright C. Ratiu, Simona Cavalu et al.

Autogenous bone blocks are valid for both horizontal and vertical augmentation but thin bone barrier and bone particles are nowadays the best choice for autograft bone augmentation. The success of vertical autogenous bone grafts in contact with teeth is always endangered by the
possibility of graft contamination. PRGF is generally useful, but especially in vertical augmentation, considering the corresponding high risk of dehiscence. Tooth extraction with simultaneous bone grafting reduces treatment time but is complicated by high risk of dehiscence; thus, tooth
extraction with PRGF, bone and soft tissue healing for four weeks prior to grafting may be a safer approach. Copyright C. Ratiu, Simona Cavalu et al.

Full text at https://rjme.ro/RJME/resources/files/600119261266.pdf

PRGF-Modified Collagen Membranes for Guided Bone Regeneration: Spectroscopic, Microscopic and Nano-Mechanical Investigations

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By C. Ratiu, Simona Cavalu et al.

The aim of our study was to evaluate the properties of different commercially available resorbable collagen membranes for guided bone regeneration, upon addition of plasma rich in growth factors (PRGF). The structural and morphological details, mechanical properties, and enzymatic degradation were investigated in a new approach, providing clinicians with new data in order to help them in a successful comparison and better selection of membranes with respect to their placement and working condition. Copyright Simona Cavalu et al.

Whole blood separation upon centrifugation at 580 G for 8 minutes at room temperature (a) and subsequent platelets rich in growth factor (PRGF) separation by pipetting (b); membrane immersion in PRGF (c). Copyright C. Ratiu, Simona Cavalu et al.

Hematology parameters of whole blood and PRGF fraction:

ComponentWhole bloodPRGF
Leukocytes (x 103/μL)5.9 ± 1.20.3 ± 0.2
Erythrocytes (x 106/μL)4.5 ± 0.40.01 ± 0.0
Platelets (x 103/μL)210 ± 20655 ± 85
Hematology parameters of whole blood and PRGF fraction. Copyright Simona Cavalu et al.
Growth factor contentValue
Transforming growth factor TGFβ1: enhances the proliferative activity of fibroblasts and stimulates the biosynthesis of collagen and fibronectin43 ng/mL
Vascular endothelial growth factor VEGF: induces angiogenesis via migrating endothelial cells220 pg/mL
Insulin –like growth factor IGF-1:  is a primary mediator of the effects of growth hormone ; can also regulate cellular DNA synthesis105 ng/mL
Platelet-derived growth factor PDGR: enhances collagen synthesis and bone cells proliferation14 ng/mL
Quantitative assessment of the main growth factors, cytokines, and chemokines in PRGF fraction. Copyright Simona Cavalu et al.
Cross-sectional scanning electron microscopy (SEM) images of different commercial collagen membranes before (a,d,g) and after (b,e,h) PRGF treatment; AFM 3D topography of the membrane surface after PRGF treatment (c,f,i) showing the details of collagen fibers. The images correspond to Biocollagen® (a–c), CovaTM Max (d–f), and Jason® (g–i). Copyright Simona Cavalu et al.
Nanoindentation measurements: load–displacement curves recorded for each membrane before (a,c,e) and after (b,d,f) PRGF treatment. The images correspond to Jason® (a,b), Biocollagen® (c,d), and CovaTM Max (e,f). Legend: MC1/MC2 = Jason® membrane before/after PRGF treatment; MCP1/MCP2 = Biocollagen® membrane before/after PRGF treatment; MPP1/MPP2 = CovaTM Max membrane before/after PRGF treatment. Copyright Simona Cavalu et al.
Young modulus calculations with respect to the three collagen membranes before (a) and after PRGF treatment (b). Legend: MPP1/MPP2 = CovaTMMax membrane before/after PRGF treatment; MC1/MC2 = Jason® membrane before/after PRGF treatment; MCP1/MCP2 = Biocollagen® membrane before/after PRGF treatment. Copyright Simona Cavalu et al.
Results of enzymatic degradation test of native (unmodified) and PRGF-modified collagen membranes. Copyright Simona Cavalu et al.

PRGF-modified collagen membranes investigated in our study present new evidence of several advantages, with respect to a rapid and predictable soft tissue healing. The structural and morphological features of three different commercial collagen membranes for GBG/GTR were investigated upon PRGF treatment, revealing that particular characteristics such as porosity, fiber density, and surface topography may influence the mechanical behavior and performance of the membranes. By FTIR spectroscopy, it was demonstrated that the collagen matrix may act as a natural reservoir for growth factor delivery. Nanoindentation measurements revealed that, upon PRGF treatment, the changes of Young modulus values are correlated with the ultrastructural properties of each membrane type, especially the porosity. The mechanical properties of the membranes were analyzed in a comparative manner, before and after PRGF modification. The enzymatic (trypsin) degradation test also emphasized a different behavior—PRGF-modified membranes exhibited a slower degradation compared with the native ones. Within the limitations of the present study, the results are important with respect to the regulation and kinetic release of multiple growth factors that can be adapted to specific therapeutic conditions. Copyright Simona Cavalu et al.