"A healthy mouth, makes a pleasant and functional
social message positive and reassuring."

dc. Maurizio Serafini

Clinical Cases

Oral Implantology

BONE REGENERATION WITH PRP GROWTH FACTORS

In odontology, tissue regeneration represents a crucial therapeutic aspect for a complete, balanced aesthetic and functional recovery.

In the last few years various techniques have been proposed and different types of materials (autologous and heterologous) have been put forward. All this has been subject to critical review through clinical trials and histological examinations.

The continuous research in optimum bone substitution materials has led to the introduction and marketing of many other materials. However, till today none of the materials studied can be considered or defined as “the perfect material” since none are limit or defect-free.

The need to solve problems related to long healing, high costs for both the operator and the patient, and the risk of cross infections, as well as the advantage of being able to prepare them at the dental surgery at the moment of performing surgery thus avoiding mistakes in the administration of medicines (occurring when they are prepared in external laboratories) have led to the creation of new technologies based on the big potential of growth factors.

The biomolecules that regulate bone cells are present in large numbers. Some are produced by the immune system, others by platelets or by osteogenic cells.

Some of these substances do not seem to be able to act alone, but only when combined with systemic hormones such as parathormone, calcitonin and vitamin D.


-PDGF (Platelet-derived growth factor):


This factor plays a significant role in the mitotic activities of tissue repair. It also plays a role in angiogenesis and osteogenesis and activates a “chemotactic call” for fibroblasts and other cells involved in wound healing (DEVEL 1982 - SPORN E ROBERTS 1986).


Growth factor placement in grafts (PRP) - “Robert Marx”

In vitro and in vivo research shows a quicker graft consolidation and mineralisation in half the normal time and a bone density improvement between 15% and 30% of the normal level. This accelerates mitogenesis and angiogenesis, as well as macrophage activation.


The PDGF content in a million platelets is equal to 0.06 mg, approximately 1,200 PDGF molecules every single platelet.


In vitro research has demonstrated that PDGF is released by platelets through a degranulation process occurring within few minutes after coming into contact with the recipient surface.


Degranulated platelets are no longer a source of growth factor release and they are replaced by macrophages, which are attracted to the graft as monocytes of the tissue hypoxia, between 0.3 and 5 mm Hg, while the surrounding tissues are between 44 and 55 mm Hg. Therefore, this difference in pressure gradient makes monocytes arrive in large numbers, and since they replicate quickly and are particularly efficient in producing growth factors, they guide the second phase of bone regeneration. As a consequence, healing - or in other words the response to the oxygen gradient - generates an early angiogenesis after only three days.

Differences between PRP and PRF


The main difference as far is PRF is concerned is that degranulation has occurred through platelets breaking during centrifugation, which results in a fibrin clot inserted as a membrane.


In PRP there are whole platelets, which are injected in the surgical site without degranulation occurring since they are not activated by calcium chloride. Due to the site rough surface they break and release growth factors.


On the contrary, when they are used to fill the gaps (post-extraction implants, split-crests, dehiscences, fistulas, cysts, etc.) they are mixed with calcium chloride and autologous bone - but not solely this type. After fibrin coagulation PRF is used in the same way as PRF.


Case reports:


1st Case report


50-year-old male patient performing a bone regeneration procedure for implant placement in the upper right sector after serious bone atrophy caused by a large periodontal granuloma like highlighted in the CT scan (image 1).

Image 2: extraction of the compromised elements.

Toilette of the surgical site. Fig 3

PRP obtained after blood centrifugation (image 4), and dextran Fisiograft sponge and gel (image 5).

Image 6: graft placement.

Image 7: control CT scan after eight months where regeneration can be noticed.

Crestal sinus lift and implant surgery with placement of two delayed load implants and control X-ray after 8 months (image 7bis).
Check-up after 8 years showing a slight reabsorption around the neck on 1.6. However, at the antrum level the bone quantity is identical to the one shown by the control X-ray after 8 months. Image 8: root reabsorption on 1.5 with bone loss on the apical.

2nd Case report


40-year-old female patient undergoing crestal sinus lift and replacement of 1.5.
The patient had been carrying a fixed prosthesis for several years, like shown by the orthopanoramic X-ray.

Image 2: blood samples, PRP is obtained after centrifugation (image 3).

Images 4 and 5: after lifting mucoperiosteal flap, 1.5 was subject to avulsion and a crestal sinus lift was performed with osteotomes. Moreover, two implants were placed.

Orthopanoramic X-ray and detail after surgery. Images 6 and 7: notice the hyper-transparency (gap) inside the sinus, demonstrating the complete lack of bone grafts and the only presence of fibrin sponges imbibed with PRP.

Images 9-10-11: orthopanoramic X-ray and CT scan showing radiographic integration and increased peri-implant bone density after six months from surgery.

Images 12 and 13: zirconia-ceramic definitive prosthesis with single teeth, notice the papillae.

3rd Case report


75-year-old female patient with a mobile prosthesis, suffering from resin allergies and wanting to have an implant inserted.
After blood examinations, within normal levels, and a computerised bone mineral measurement of the spine and femur – since she had been taking Strontium ranelate for two years, maintaining a perfect bone balance – she underwent implant surgery and sinus lift procedure (image 1).


Images 2 and 3: blood samples and PRP.

Control X-ray after 24 months showing perfect bone formation of the maxillary sinus (negatives of image 4 and 5).