**5. Discussion**

The results of the present report provide evidence for the biocompatibility and osteoconductive properties of Synergy Bone Matrix. Bone graft implantation is the main treatment modality for bone defect repair and reconstruction [3]. In this sense, demineralized bovine bone offers excellent biocompatibility and physicochemical properties due to its mineral similarity with the host tissues [43].

SBM and BO are inorganic bovine bone xenografts indicated for bone defects filling due to their osteoconductive properties. In experimental models, the bone defect above a critical size requires a scaffold to guide bone repair. Deproteinized bovine bone mineral is osteoconductive and provides excellent biocompatibility because it has similar physicochemical characteristics to that of the mineral component of the original bone [3]. These two important biological properties allow apposition of new bone formed by osteoprogenitor cells located in the host tissue. It is noteworthy that bovine bone inorganic-phase not only promotes the deposition of calcium and phosphate ions but also is partially remodeled by osteoclasts and osteoblasts of the host [25]. In addition, the large interconnecting pore volume and its composition encourage the formation and ingrowth of new bone at the implantation sites.

BO is a recognized commercial bone defect filling material with osteoconductive properties. Under our experimental conditions, SBM showed similar osteoconductive properties to BO. In this regard, our histological findings showed neovascularization in the area implanted with either SBM or BO. This finding suggests that the new bone graft provided an optimal microenvironment for bone ingrowth. Typically, bone formation starts by bone-forming cells secreting bone matrix (i.e., collagen) into the defect area, followed by mineralization to envelope the implanted graft material [44]. Our results in rats showed that collagen fibers were replaced by mature bone, filling the CSBD, thus confirming active osteogenesis after 24 days postimplantation of the graft.

Similarly to what we observed in rats, histological analysis in rabbits at 4 weeks postimplantation showed the presence of blood vessels and revascularization in the areas implanted with both bone grafts. This finding suggests an optimal microenvironment for bone growth. Bone formation begins with the appearance of osteoblasts in the defect area that secretes bone matrix (i.e. collagen); this period is followed by mineralization in order to wrap the implanted graft material [44].

SBM, as well as gradual regression of associated fibrosis. The bone formation pattern was lamellar and trabecular, and the presence of osteoblast at the surface of the trabeculae, as well as osteocytes, was also observed. There were no signs of inflammation or bone sequestrae.

Postoperative 4-month control digital images exhibited osseointegration of the implants (**Figure 10**). No peri-implant radiolucencies were observed. The regenerated bone gain by the graft placement in both sides was preserved (**Figure 10**). Clinical assessment of the dental implants did not exhibited mobility of the implants, and a solid-deaf sound when performing percussion tests showed proper bone healing. The patient did not report pain, and there was no leakage of purulent material or signs of inflammation. In addition, the grafted bone

The results of the present report provide evidence for the biocompatibility and osteoconductive properties of Synergy Bone Matrix. Bone graft implantation is the main treatment modality for bone defect repair and reconstruction [3]. In this sense, demineralized bovine bone offers excellent biocompatibility and physicochemical properties due to its mineral similarity

SBM and BO are inorganic bovine bone xenografts indicated for bone defects filling due to their osteoconductive properties. In experimental models, the bone defect above a critical size requires a scaffold to guide bone repair. Deproteinized bovine bone mineral is osteoconductive and provides excellent biocompatibility because it has similar physicochemical characteristics to that of the mineral component of the original bone [3]. These two important biological properties allow apposition of new bone formed by osteoprogenitor cells located in the host tissue. It is noteworthy that bovine bone inorganic-phase not only promotes the deposition of calcium and phosphate ions but also is partially remodeled by osteoclasts and osteoblasts of the host [25]. In addition, the large interconnecting pore volume and its composition encour-

BO is a recognized commercial bone defect filling material with osteoconductive properties. Under our experimental conditions, SBM showed similar osteoconductive properties to BO. In this regard, our histological findings showed neovascularization in the area implanted with either SBM or BO. This finding suggests that the new bone graft provided an optimal microenvironment for bone ingrowth. Typically, bone formation starts by bone-forming cells secreting bone matrix (i.e., collagen) into the defect area, followed by mineralization to envelope the implanted graft material [44]. Our results in rats showed that collagen fibers were replaced by mature bone, filling the CSBD, thus confirming active osteogenesis after 24 days

Similarly to what we observed in rats, histological analysis in rabbits at 4 weeks postimplantation showed the presence of blood vessels and revascularization in the areas implanted with both bone grafts. This finding suggests an optimal microenvironment for bone growth.

presented the similar density than the perisinusal bone at both sides.

86 Bone Grafting - Recent Advances with Special References to Cranio-Maxillofacial Surgery

age the formation and ingrowth of new bone at the implantation sites.

**5. Discussion**

with the host tissues [43].

postimplantation of the graft.

Bone is a dynamic tissue that undergoes remodeling. Bone remodeling is a coupled process that starts with osteoclastic bone resorption followed by osteoblastic bone formation [45]. In this sense, the osteoclastic resorption of the graft is affected by both, the particle size as well as the composition and porosity of the material.

Initially, once the graft material is place, it suffers osteoclastic bone resorption followed by bone formation by osteoblastic action. The porosity of the particles enhances new bone formation by allowing the migration and proliferation of osteoblast and mesenchymal cells [46]. In addition, the microporosity of the particles is believed to enhance ionic exchange with body fluids [46]. This characteristic allows each particle of SBM to serve as a 3-D scaffold, in which osteoblast and osteoprogenitor cells migrate and form bone. Consistent with this, during the first period (4 weeks), we observed active osteogenesis evidencing by the presence of bone surfaces covered by osteoblasts around the implanted bone grafts and the formation of mature haversian systems. Toward the end of the experience, the collagen fibers were replaced by mature bone that filled the CSBD region. These findings indicate that the process of bone regeneration induced by SBM was similar to that induced by BO.

It is important to emphasize the quantity and quality of bone formed after placing a bone graft. On this regard, the increase in rat tibiae BMD indicates that the amount of bone increased in the CSBD filled with SBM or BO. In addition, biomechanical test performed in rabbit mandible exhibited an increase in all parameters, suggesting an enhanced quality of the newly formed bone.

Chackarti et al. observed, in a histomorphometric and micro-CT analysis, that granules from different sizes (small or large), produced the same pattern of bone formation: the bone surrounding the graft connects and produces a network of "bone bridges" among the graft particles [47]. The two used bone grafts had a similar granulometry: 1 to 2 mm for BO and 0.84 to 2 mm for SBM. Although BO and SBM are available in small granules as well as blocks, these were considered too small or too large for the rabbit experimental model used. In the present study, the volume of remaining bone graft particles was similar, and the biomechanical results did not show differences between SBM or BO, suggesting that the quality of the bone formed was similar for both products.

The loss of teeth in the posterior area of the maxilla leads to adverse consequences on masticatory function and occlusal balance. These outcomes negatively results in psychophysical conditions associated with temporomandibular joint and muscle diseases. A frequent problem in oral rehabilitation with implant-supported prostheses in the posterior maxilla is the lack of bone volume associated with alveolar ridge resorption or maxillary sinus pneumatization [48]. The reabsorption of the alveolar bone, adjacent to the floor of the maxillary sinus, may be aggravated by the increase in osteoclastic activity that originates in the periosteum of Schneider's membrane, after tooth loss, due to the absence of osteogenesis normally stimulated by the functional load on the bone. In this sense, the bone volume is limited due to the pneumatization of the maxillary sinus on one hand and the loss of height and width of the alveolar process on the other. In order to increase the bone volume, the maxillary sinus floor elevation technique is used. It consists in elevating the membrane of the floor of the maxillary sinus and filling the intermediate space with bone substitutes [42] to promote bone formation [49]. The results of this procedure can be affected by the surgical techniques used: simultaneous placement versus delayed implantation of the implant, use of barrier membranes on the lateral window, graft material selection and surface characteristics, and length and width of the implants. Depending on the type of graft, the particles are partially reabsorbed and replaced by the patient's own bone during the healing time [50].

and University of Buenos Aires, School of Dentistry, Department of Clinical Operative and

Update on Bone Grafting Materials Used in Dentistry in the Bone Healing Process: Our…

This research was partially funded by National Council of Scientific and Technical Research (CONICET)-University of Buenos Aires. Institute of Immunology, Genetics and Metabolism (INIGEM). School of Pharmacy and Biochemistry- Clinical Hospital "José de San Martín," Buenos Aires, Argentina, and Odontit Implant Systems, Argentina. Synergy Bone Matrix and

, Miguel A. Pellegrini1

, Elizabeth Arandia Osinaga<sup>3</sup>

1 CONICET-University of Buenos Aires, Institute of Immunology, Genetics and Metabolism (INIGEM), School of Pharmacy and Biochemistry, Clinical Hospital "José de San Martín",

2 Department of General and Oral Biochemistry, School of Dentistry, University of Buenos

[1] Elsalanty ME, Genecov DG. Bone grafts in craniofacial surgery. Craniomaxillofacial

[2] Albee FH. The fundamental principles underlying the use of the bone graft in surgery. In: Saunders B, editor. Bone-graft surgery. Philadelphia and London: W. Company;

[3] Petite H, Viateau V, Bensaid W, Meunier A, De Pollak C, Bourguignon M, et al. Tissue engineered bone regeneration. Nature Biotechnology. 2000;**18**:959-963. DOI: 10.1038/79449 [4] Fuentes Fernández R, Bucchi C, Navarro P, Beltrán V, Borie E. Bone grafts utilized in dentistry: An analysis of patients' preferences. BMC Medical Ethics. 2015;**16**:71. DOI:

Trauma and Reconstruction. 2009;**2**:125-134. DOI: 10.1055/s-0029-1215875

3 Department of Clinical Operative and Prosthesis II, School of Dentistry, University of

, Luis A. Corso3

http://dx.doi.org/10.5772/intechopen.79261

89

and Susana N. Zeni1,2

,

Prosthesis II, Buenos Aires, Argentina for their assistance in the use of the facilities.

Bio-Oss were kindly provided by Odontit Implant Systems, Argentina.

All authors state that they have no conflicts of interest.

\*Address all correspondence to: gp2571@cumc.columbia.edu

Gretel G. Pellegrini1,2\*, Andrea S. Mattiuzzi<sup>3</sup>

**Conflict of interest**

**Author details**

Cintya P. Contreras Morales3

Buenos Aires, Argentina

1915. pp. 17-51

10.1186/s12910-015-0044-6

**References**

Aires, Buenos Aires, Argentina

Buenos Aires, Buenos Aires, Argentina

In agreement with Shirmohammadi et al. and Wallace et al. on sinus augmentation utilizing BO as bone graft [51, 52], the case report presented here evidences the efficacy of SBM in the bone healing process, showing osteoconductive properties when used as a grafting material for sinus lift elevation. In this regard, biopsies of the grafted areas showed that SBM particles were surrounded by vital new bone, without evidence of inflammation and bone sequestrae after 6 months of implantation. We neither observed inflammation nor thickening of the repaired Schneiderian membrane.

Additional comparative studies with greater number of patients and histomorphometric analysis are needed to determine whether there is any advantage in the use of SBM as opposed to BO in the survival of implants placed in grafted sinuses.

## **6. Conclusion**

The use of bone grafts is important to preserve the alveolar bone ridge height and volume indispensable for dental implant placement. Despite the highly successful outcomes for the implant-supported overdentures, it seems that a majority of edentulous individuals have not pursued implant-based rehabilitation. Among the reasons cited for this discrepancy between highly successful therapy, and its acceptance is the cost of the treatment [53]. Our experimental findings in animal models, as well as the case report, indicate that the bone regeneration process induced by SBM presented similar characteristics in osteoconduction than BO and suggests the use of this material to increase the bone volume of the alveolar crest. The presence of a biomaterial with similar characteristics to those of internationally recognized commercial brands, but developed by the domestic industry, will be an important tool to reduce the high cost of these interventions.
