**4. Use of a combination of particulate allograft (DFDBA) and platelet concentrates (PRF) in oral and maxillo-facial surgery**

In our department, we routinely use a combination of particulate allograft (DFDBA 300–500 μm) and platelet concentrates (PRF) for the preservation of alveolar bone volume after dental extractions, for sinus grafts (sinus lifts), and for horizontal and vertical bone grafts.

The DFDBA comes from the cortical part of the long bones of the lower limbs of deceased tissue donors in the Erasmus Hospital Bone and Tissue Bank. It is collected by the Erasmus Bone and Tissue Bank team. The samples are then demineralized in HCl to obtain a residual calcium value <10%. Sterilization is then performed using two chemical baths of NaOH and H202 validated by the Institut Pasteur for the destruction of bacteria and viruses and finally undergoes Gamma 25 kGy irradiation at the end of the process. The different particle sizes are obtained by sieving.

To assess whether this DFDBA and PRF mixture was favorable for post-extraction bone filling, we conducted clinical and histological/histomorphometric research.

First, a retrospective radiological clinical study was conducted on 56 patients for whom 95 extractions had been done, to evaluate vertical alveolar bone loss 3 months after tooth extraction, to find out if a combination of particulate allograft (300–500 μm) and PRF could be beneficial for the patient, with predictable results, *The Combined Use of Particulate Allografts (DFDBA) and Platelet Concentrates in Oral… DOI: http://dx.doi.org/10.5772/intechopen.111848*

to preserve alveolar bone volume. Three months after tooth extraction, the mean of vertical loss of the midbuccal bone wall was 0.72 (SD 0.71) mm (5.53%), indicating a good potential for the technique using DFDBA 300–500 μm and platelet concentrates in alveolar bone preservation [25].

In a second study [26], a retrospective clinical study was performed. A total of 84 patients were included with 247 dental implants, to compare peri-implant bone loss at implants placed in alveolar sockets filled with a particulate allogenous bone graft (DFDBA 300–500 μm) and platelet concentrates *versus* at implants placed in the native bone. At 6 and 12 months, the peri-implant bone loss in sockets preserved with DFDBA and platelet concentrates was similar to the peri-implant bone loss in native bone.

In a recent study [27] to evaluate the bone quality of sinus and alveolar grafts following filling with particulate allogenous bone (DFDBA 300–500 μm) and platelet concentrate (PRF), we realized a prospective interventional clinical and histomorphometric study. A total of 40 bone cores, 2 mm in diameter, were taken from 21 patients: 22 from grafted alveoli, 7 from grafted sinus sites, and 11 from native bone used as a control. Fixed, paraffin-embedded samples were subjected to histological staining with hematoxylin–eosin and Masson's trichrome. Bone maturity of the samples was evaluated by two independent operators using histomorphometric analysis. There existed a greater proportion of lamellar neoformed bone than woven neoformed bone as the healing time increased. Moreover, there was also an increasing proportion of newly formed bone in the grafted sockets as a function of healing time (average: 41.22% ≤ 5 months, 55.89% ˃ 5 months). Resorption of DFDBA particles also appears to be correlated with healing time in the grafted socket (average: 15.43% ≤ 5 months, 13.72% ˃ 5 months). We were able to conclude that performing sinus lift and alveolar socket preservation techniques using DFDBA and PRF results in high-quality, mature bone tissue according to histological criteria.

Our studies show that the use of particulate DFDBA mixed with platelet concentrate (PRF) leads to good clinical results with regard to post-extraction bone preservation and success rate of implants placed in the grafted bone. Moreover, a histomorphometric study shows that this technique results in a high-quality mature bone according to histological criteria.

#### **4.1 Horizontal and vertical bone grafting**

For bone grafting of the maxillas, autologous bone grafting has long been considered the gold standard owing to its osteogenic, osteoconductive, and osteoinductive properties [28]. However, this graft, which is taken from intra- or extraoral donor sites, limits the amount of bone available and requires a second invasive surgical procedure, thus increasing the risk of post-operative morbidity [29]. Moreover, it features a mean resorption rate of 50% [28].

Demineralized freeze-dried bone allograft (DFDBA) in the particulate form has been used successfully for many years in the Stomatology and Maxillofacial Surgery Department of the Erasmus Hospital for bone grafting procedures in maxillo-facial and implant surgery.

Its particulate character (particles whose diameter is between 300 and 500 μm and 500–1000 μm) allows its easy adaptation to the recipient bone bed. Nevertheless, the forces applied by the soft tissues can compromise its stability and the maintenance of

the volume of the graft, and it is necessary to add a mechanical means of maintenance of volume during the integration period of the bone graft.

The principle of guided bone regeneration (GBR) consists in placing the graft material under a support acting as a space maintainer, to prevent the non-osteogenic tissues from interfering with bone regeneration [30].

To this end, the use of titanium osteosynthesis screws arranged as a "tent peg" is currently considered an effective therapeutic procedure in the treatment of significant vertical bone deficits (**Figure 1**) [31].

We recently performed a 2-year clinical prospective study [submitted] to quantify the study of horizontal oral bone ridge augmentation using GBR with an association of particulate allografts mixed with platelet-rich fibrin, collagen membrane, and tenting screws. This study aimed to radiologically evaluate the horizontal bone gain. A total of 42 patients with an insufficient alveolar bone width for dental implant placement were treated with a GBR technique using a mixture of particulate allograft (demineralized freeze-dried bone allograft 300–500 and 500–1000 μm), advanced platelet-rich fibrin (A-PRF), resorbable collagen membranes, and screw tents (1.2 mm in diameter). Bone gains were measured by cone-beam computed tomography (CBCT) at 9.1 ± 2.0 months post-operatively. A significant mean increase (P < 0.001) of 3.2 ± 0.9 mm was observed regardless of bone defect location and without complications during the entire post-operative follow-up. All patients benefited from implant placement following the bone augmentation protocol.

We were able to conclude that maxillomandibular bone augmentation in the horizontal plane by the guided bone regeneration technique using a mixture of particulate allograft, platelet concentrates (A-PRF), and screw-tent in combination with a flap closure technique tension-free mucoperiosteal was a procedure that provides reliable, predictable, and reproducible clinical results. This guided bone regeneration technique differs from previous studies on the subject by its qualitative aspects. Indeed, it is easy to use, considerably reducing operating time, with a low complication rate and an absence of morbidity associated with the donor site in the context of autologous bone harvesting. In addition, all the materials and methods used in the context of this technique are reimbursed for the patient.

#### **Figure 1.**

*The placement of osteosynthesis screws arranged in a "tent peg" to counter the forces exerted by the soft tissues. After placement of the demineralized freeze-dried bone allograft (DFDBA) and platelet-rich fibrin (PRF) mixture against the recipient bone bed, a collagenic membrane is positioned to cover the graft. The mucosal flap can be put back in place with sutures.*

*The Combined Use of Particulate Allografts (DFDBA) and Platelet Concentrates in Oral… DOI: http://dx.doi.org/10.5772/intechopen.111848*

#### *4.1.1 Clinical case: Horizontal bone grafting*

This 51-year-old woman, totally edentulous at the maxilla, presents with significant horizontal bone resorption of the upper jaw (Class IV by Cawood et al. [32]). She wants an implant-supported rehabilitation solution, and it is necessary to perform bone reconstruction before placing implants (**Figure 2**).

Computed tomography (CT) scan in left (B) and right (C) premolar areas shows important horizontal loss of the maxillary bone (**Figures 3**–**6**).

#### **Figure 2.**

*Intrabuccal clinical view (A) showing horizontal bone resorption of the maxilla.*

#### **Figure 3.**

*Surgical procedure. A mucoperiosteal incision is made (A) and a mucoperiosteal flap is released. Screws (1.2 mm diameter) are placed (B), to allow guided bone regeneration and four temporary implants are placed avoid prosthesis pressure on the grafted site. A mix of particulate allograft (demineralized freeze-dried bone allograft (DFDBA) 300–500 μm) and platelet concentrate (platelet-rich fibrin (PRF)) is applied between the screws, in tied contact with bone, and covered with a collagen membrane then by PRF membranes (C). Flap is sutured in place without any tension (D).*

#### **Figure 4.**

*Radiological assessment 9 months later. The panoramic X-ray (A) and the computed tomography (CT) scan in right premolar (B), left premolar (C), and anterior (D) areas show a bone gain of between 4 and 5 mm over the entire area that has been grafted.*

**Figure 5.** *The placement of six implants 9 months after the grafting procedure, together with removal of tenting screws.*

#### *4.1.2 Clinical case: Vertical bone grafting*

This 31-year-old woman underwent exeresis of a myxoma of the anterior part of the maxilla 9 years ago. Consecutively, she had lost a part of anterior maxilla, as well as teeth 11, 12, and 13. Clinically, there is a vertical bone loss, together with retracted scar gingiva (**Figures 7**–**11**).

*The Combined Use of Particulate Allografts (DFDBA) and Platelet Concentrates in Oral… DOI: http://dx.doi.org/10.5772/intechopen.111848*

#### **Figure 6.**

*The final prosthetic result. Six months after the placement of implants, the patient can be provided with a fixed upper bridge screwed on implants.*

#### **Figure 7.**

*Clinical view showing vertical bone loss in the area where a myxoma of the anterior part of the maxilla had been removed 9 years ago.*

#### **Figure 8.**

*Panoramic X-ray (A) and computed tomography (CT)-scan axial (B) and sagittal (C) views show the voluminous loss of bone in the anterior region of the maxilla.*

#### **Figure 9.**

*The day of bone reconstruction, a mucoperiosteal flap is raised, then 1.2 mm screws are placed (A), then a mixing of particulate demineralized freeze-dried bone allograft (DFDBA) 300–500 and 500–1000 (2/1)/platelet-rich fibrin (PRF) are compacted against the recipient bone bed (B), the PRF membranes are placed to cover the graft (C), and the site is sutured together with anterior shift of gingival papillas (D).*

#### **Figure 10.**

*Nine months later, X-ray assessment: Panoramic X-ray (A), cephalometric R-ray (B), and computed tomography (CT) scan in axial (C) and sagittal (D) views show a good bone reconstruction in the grafted area.*

*The Combined Use of Particulate Allografts (DFDBA) and Platelet Concentrates in Oral… DOI: http://dx.doi.org/10.5772/intechopen.111848*

#### **Figure 11.**

*Two implants could be placed into the bone graft, and the patient was provided with a fixed bridge screwed on implants.*

### **5. Conclusion**

Particulate allografts are commonly used in oral and maxillo-facial surgery. Particulate Demineralized Freeze Dried Bone Allograft (DFDBA) is mainly used in a granulometry 300–500 μm. Mixed with platelet concentrates, it is a material that is easy to handle and to mold in place on bone beds.

Clinical and histomorphometric studies carried out by our team show that the use of this DFDBA and PRF combination gives good results for post-extraction bone volume conservation, maxillary sinus grafts, horizontal and vertical maxillary augmentations.

### **Conflict of interest**

The author declares no conflict of interest.
