**1. Introduction**

Bone graft is an implanted material that promotes bone healing alone or in combination with other material(s) [1]. The use and success of bone grafts in the medical field date from the

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

beginning of the nineteenth century. In this regard, Albee in 1915 had depicted that there were successfully bone transplants in animal models, as well as in humans, since 1809 [2]. Nowadays, bone graft implantation is the main treatment modality for bone defect repair and reconstruction [3]. In oral and maxillofacial areas, bone grafting aims to replace the volumetric bone loss that frequently occurs by systemic pathologies, periodontal defects, and tooth loss [4].

are osteoconductive and have been shown to integrate to bone [27]. There are many available kinds of synthetic graft materials, including bioactive glasses, a- and b-tricalcium phosphate

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

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

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Bioactive glass or "bioglasses" has been widely used as bone substitutes because of their ability to join and integrate with the bone tissue by forming a layer of active apatite on its surface, with characteristics similar to bone [28]. These biomaterials are resorbable, and dissolution of their products (soluble silicon and calcium) upregulates seven families of genes present in osteoblasts (bone forming cells), thus promoting osteogenesis [28, 29]. Among synthetic materials, synthetic hydroxyapatite, a crystalline phase of calcium phosphate found naturally in bone minerals, exhibits initial mechanical rigidity and structure and demonstrates osteoconductive, as well as angiogenic properties in vivo [30]. Because of its physicochemical characteristics, synthetic hydroxyapatite is a biocompatible and osteoconductive material [31]. This material allows to keep the space filled extremely well providing a physical matrix for the deposition of new bone. For these reasons, synthetic hydroxyapatite has high success

Due to the high popularity of dental implant surgery, the demand for alveolar ridge reconstruction, including sinus augmentation and immediate implant procedures, increased. This new trend in dentistry for implants boosted the development of new grafting materials in dentistry. Ideally, a bone graft should be biocompatible, biodegradable, osteoconductive, and osteoinductive, structurally similar to bone, easy to use, and cost-effective [7]. Within these parameters, a growing number of bone graft alternatives are commercially available and fre-

Different types of bone grafts are available in the international market. However, it is essential to have a wide variety of them to improve the competitivity of each product in terms of quality, commercial value, and clinical use. Therefore, the development of biomaterials for bone grafting, produced by domestic manufactures, with comparable characteristics and biological effects than those renowned internationally, is necessary in order to reduce the high costs in public health arising from the application of these biomaterials in the dental field. The aim of the following chapter is to offer an update on one bone grafting material frequently used in dentistry through an assessment of an organic bovine bone graft in small and medium

We evaluated and compared the effects of a bovine bone graft made in Argentina with a commercial bovine bone graft recognized for its osteoconductive effects, on bone healing process

The research and all procedures involving live animals were processed after approval by the Clinical Hospital, School of Medicine, University of Buenos Aires, Argentina. Animals were

in experimental models in rats (experiment 1) and rabbits (experiment 2).

(TCP), and synthetic hydroxyapatite [27].

in the fields of biology, medicine, and dentistry.

experimental models, as well as its clinical use.

quently used in dentistry.

**2. Translational studies**

**2.1. Materials and methods**

The mechanisms underlying the bone healing promoted by a bone graft are osteogenesis (osteodifferentiation and subsequent new bone formation by donor cells derived from the host or graft), osteoinduction (induction of undifferentiated and pluripotent cells to develop osteogenesis into the bone-forming cell lineage), and osteoconduction (the ability to support the attachment of osteoblast and osteoprogenitor cells and the migration and ingrowth of these cells within the three dimensional architecture of the graft) [5, 6], in combination or alone [7].

Bone grafting materials are classified as autografts (derived from the same individual), allografts (derived from a different individual from the same species), xenografts (derived from a different species), and alloplasts (derived from synthetic sources) [8]. Autografts are the "gold standard" in the reconstruction of bone defects due to their osteoconductive as well as osteoinductive properties [9]. Although they present excellent biological outcomes, they also have a number of drawbacks. In this regard, the use of autografts increases the operative time due to graft harvest, increases the donor site morbidity, and increases the graft resorption. In addition, they represent a big challenge for the operator, since they need to be mold and have limited availability, especially in the pediatric population [10]. Allografts are typically obtained from human cadavers and require to be processed before being used [11, 12]. Allograft bone is available as cortical, cancellous, corticocancellous forms, or as demineralized bone matrix. They can be processed as mineralized or demineralized, fresh, fresh-frozen, or freeze-dried forms [13, 14]. Among the benefits of allografts are their availability in different shapes and sizes. This is particularly advantageous, since it avoids donor site morbidity [15]. The major disadvantages of allografts are related to the transmission of diseases and the graft rejection. In order to decrease the risk of transmitting infectious diseases, allografts need to be treated. The techniques employed include treatment with hypotonic solutions, acetone, ethylene oxide, or gamma irradiation that may eliminate cellular and viral particles [16]. However, these processes eliminate the bone cells and denature proteins present in the graft altering the osteoconductive and osteoinductive properties and eliminating the osteogenic properties [17]. In addition, allografts are capable to induce immunological reactions that interfere with the bone healing process leading to rejection of the graft [15, 18–20]. Xenografts are frequently derived from bovine, porcine, and coral sources [7]. The effectiveness of different bone processing techniques has made possible the use of these materials for medical applications [21, 22]. Bovine bone is one of the most popularly used xenografts. This source material is desirable because it is readily available an inexpensive. However, bovine bone grafts require proper preparation to avoid risks such as transmission of zoonoses [23]. Several studies have shown that organic or inorganic matrix derived from bovine bone is biocompatible and osteoconductive [23, 24]. These important biological properties allow the apposition of newly formed bone by osteoprogenitor cells and the partial remodeling by osteoclasts and osteoblasts of the host [25]. Moreover, the large interconnecting pore volume and its composition encourage the formation and ingrowth of new bone at the implantation sites. Ideally, a synthetic bone graft should be biocompatible and causes minimal fibrotic changes [26]. Synthetic bone grafts are osteoconductive and have been shown to integrate to bone [27]. There are many available kinds of synthetic graft materials, including bioactive glasses, a- and b-tricalcium phosphate (TCP), and synthetic hydroxyapatite [27].

Bioactive glass or "bioglasses" has been widely used as bone substitutes because of their ability to join and integrate with the bone tissue by forming a layer of active apatite on its surface, with characteristics similar to bone [28]. These biomaterials are resorbable, and dissolution of their products (soluble silicon and calcium) upregulates seven families of genes present in osteoblasts (bone forming cells), thus promoting osteogenesis [28, 29]. Among synthetic materials, synthetic hydroxyapatite, a crystalline phase of calcium phosphate found naturally in bone minerals, exhibits initial mechanical rigidity and structure and demonstrates osteoconductive, as well as angiogenic properties in vivo [30]. Because of its physicochemical characteristics, synthetic hydroxyapatite is a biocompatible and osteoconductive material [31]. This material allows to keep the space filled extremely well providing a physical matrix for the deposition of new bone. For these reasons, synthetic hydroxyapatite has high success in the fields of biology, medicine, and dentistry.

Due to the high popularity of dental implant surgery, the demand for alveolar ridge reconstruction, including sinus augmentation and immediate implant procedures, increased. This new trend in dentistry for implants boosted the development of new grafting materials in dentistry. Ideally, a bone graft should be biocompatible, biodegradable, osteoconductive, and osteoinductive, structurally similar to bone, easy to use, and cost-effective [7]. Within these parameters, a growing number of bone graft alternatives are commercially available and frequently used in dentistry.

Different types of bone grafts are available in the international market. However, it is essential to have a wide variety of them to improve the competitivity of each product in terms of quality, commercial value, and clinical use. Therefore, the development of biomaterials for bone grafting, produced by domestic manufactures, with comparable characteristics and biological effects than those renowned internationally, is necessary in order to reduce the high costs in public health arising from the application of these biomaterials in the dental field. The aim of the following chapter is to offer an update on one bone grafting material frequently used in dentistry through an assessment of an organic bovine bone graft in small and medium experimental models, as well as its clinical use.
