**4. Bioactive ceramic biomaterials**

Bioactive refers to a material, which upon being placed within the human body interacts with the surrounding bone and in some cases, even soft tissue. This occurs through a time – dependent kinetic modification of the surface, triggered by their implantation within the living bone. An ion – exchange reaction between the bioactive implant and surrounding body fluids – results in the formation of a biologically active carbonate apatite (CHAp) layer on the implant that is chemically and crystallographically equivalent to the mineral phase in bone. Prime examples of these materials are synthetic hydroxyapatite, glass ceramic and bioglass.

Calcium phosphate ceramics and xenografts have been used in different fields of medicine and dentistry. We demonstrated the effects of calcium phosphate ceramics (Ceraform) and xenograft (Unilab Surgibone) in the field of experimentally created critical size parietal and mandibular bone defects in rats (Develioglu et al., 2006, 2007, 2009, 2010).

Many researches are currently conducted to find out the ideal material to support bone repair or regeneration. The limitations of autogenous grafts and allogeneic bankbone have led to a search for synthetic alloplast alternatives. Calcium phosphate ceramics have been

Histopatological Effect Characteristics of Various

M-T, 4X.

Biomaterials and Monomers Used in Polymeric Biomaterial Production 439

Fig. 18. Remnants of the Xenograft (\*) surrounded by fibrous tissue at 30 days. A-T 4X.

Fig. 19. A dense, fibrovascular tissue (\*) in the side of ceraform implantation at 12th month

Fig. 20. Multinuclear giant cell (↔)in the implantation site. H-E, 40X

widely used because the mineral composition of these implants materials does fully biocompatible (Rey C. 1990, LeGeros. 2002). The porous structure of the ceramics is claimed to enhance bone deposition and implant stabilization in the recipient bone. The optimal pore size is still debated to be ranging from 50 and 565 μm (Gauthier et al., 1998, Chang et al., 2000). However, porosity of the material is inversely proportional to the mechanical stability of these calcium phosphate based ceramics (Le Huec et al., 1995). This loss of stability is often cited as a limitation in the use of calcium phosphate-based ceramics in clinical practice. A convenient compromise to overcome this problem is to use a biphasic ceramic, which maintains its mechanical resistance until the resorption is achieved (Gauthier et al., 1998).

Various types of xenografts are used in medicine, dentistry, and also in periodontology. One of the xenografts is Unilab Surgibone, which is currently being used succesfully in medicine and implantology. Moreover, osteoconductive properties are also known (Zhao et al., 1999). Unilab Surgibone is obtained from freshly sacrificed calves which is partially deproteinized and processed by the manufacturers. It is available in varius shapes like tapered pins, blocks, cubes, granules, circular discs and pegs (Balakrishnan et al., 2000). Xenograft materials, bovine bones have been the most preferred ones, basically because they are easily obtainable and there are no great ethical considerations. Additionally they have the great advantage of practically unlimited availability of source/raw material. Partially deproteinized and defatted preparations (e.g.Unilab Surgibone) was indicated reduce antigenity and mild immune response (William et al., 2008).

Generally, xenografts are one of the alternative graft materials used in different fields for filling osseous defects Slotte and Lundgren, 1999, Salama 1983). Nonetheless, an interesting alternative to xenografts is Biocoral® (natural coral), which has been shown to exhibit osteoconductive and biocompatible properties whereby gradual replacement with newly formed bone occurred after its resorption (Guillemin et al.,1989, Doherty et al., 1994, Ylmaz and Kuru, 1996, Yukna Ra and Yukna CN, 1998).

Another xenogeneic, bone-derived implant material is Bio-Oss, which is similar to the xenograft investigated in our studies (Develioglu et al.2009, 2010). Bio-Oss has been proposed as a biocompatible graft material for bony defects for it has shown osteoconductive properties — that is, it was replaced with newly formed bone after grafting (Yldrm et al, 2001, Sculean et al., 2002, Carmagnola et al., 2002). However, regarding the resorption of Bio-Oss, contradicting reports have emerged. On one hand, a previous study revealed that the bovine bone mineral underwent resorption (Pinholt et al., 1991). On the other hand, numerous researchers claimed that the resorption process of Bio- Oss® was very slow (Skoglund et al., 1997, Jensen et al 1996, Klinge et al., 1992).

In our previous studies with Ceraform (calcium phosphate ceramics) and xenograft (Unilab Surgibone), multinuclear giant cells (MNGC) were observed in the implantation region on 1st, 3rd, 6th ve 18th months.

The observed MNGCs are featured morphologic characteristics of foreign body giant cell (FBGC). These cells are osteoclast-like cells. Both cell types develop from a common precursor (Anderson, 2000) Since foreign body giant cell (FBGC) are the fusion products of monocytic precursors, which are also the precursors of macrophages, (Brodbeck at al., 2002, Matheson et al., 2004) the presence of such leukocytes in the wound healing compartment may be of central importance in driving the tissue reaction to the material. No necrosis, tumorigenesis, or infection was observed at the implant site up to 18 months (Figure 18-20).

widely used because the mineral composition of these implants materials does fully biocompatible (Rey C. 1990, LeGeros. 2002). The porous structure of the ceramics is claimed to enhance bone deposition and implant stabilization in the recipient bone. The optimal pore size is still debated to be ranging from 50 and 565 μm (Gauthier et al., 1998, Chang et al., 2000). However, porosity of the material is inversely proportional to the mechanical stability of these calcium phosphate based ceramics (Le Huec et al., 1995). This loss of stability is often cited as a limitation in the use of calcium phosphate-based ceramics in clinical practice. A convenient compromise to overcome this problem is to use a biphasic ceramic, which maintains its mechanical resistance until the resorption is achieved (Gauthier et al., 1998). Various types of xenografts are used in medicine, dentistry, and also in periodontology. One of the xenografts is Unilab Surgibone, which is currently being used succesfully in medicine and implantology. Moreover, osteoconductive properties are also known (Zhao et al., 1999). Unilab Surgibone is obtained from freshly sacrificed calves which is partially deproteinized and processed by the manufacturers. It is available in varius shapes like tapered pins, blocks, cubes, granules, circular discs and pegs (Balakrishnan et al., 2000). Xenograft materials, bovine bones have been the most preferred ones, basically because they are easily obtainable and there are no great ethical considerations. Additionally they have the great advantage of practically unlimited availability of source/raw material. Partially deproteinized and defatted preparations (e.g.Unilab Surgibone) was indicated reduce

Generally, xenografts are one of the alternative graft materials used in different fields for filling osseous defects Slotte and Lundgren, 1999, Salama 1983). Nonetheless, an interesting alternative to xenografts is Biocoral® (natural coral), which has been shown to exhibit osteoconductive and biocompatible properties whereby gradual replacement with newly formed bone occurred after its resorption (Guillemin et al.,1989, Doherty et al., 1994, Ylmaz

Another xenogeneic, bone-derived implant material is Bio-Oss, which is similar to the xenograft investigated in our studies (Develioglu et al.2009, 2010). Bio-Oss has been proposed as a biocompatible graft material for bony defects for it has shown osteoconductive properties — that is, it was replaced with newly formed bone after grafting (Yldrm et al, 2001, Sculean et al., 2002, Carmagnola et al., 2002). However, regarding the resorption of Bio-Oss, contradicting reports have emerged. On one hand, a previous study revealed that the bovine bone mineral underwent resorption (Pinholt et al., 1991). On the other hand, numerous researchers claimed that the resorption process of Bio- Oss® was very

In our previous studies with Ceraform (calcium phosphate ceramics) and xenograft (Unilab Surgibone), multinuclear giant cells (MNGC) were observed in the implantation region on

The observed MNGCs are featured morphologic characteristics of foreign body giant cell (FBGC). These cells are osteoclast-like cells. Both cell types develop from a common precursor (Anderson, 2000) Since foreign body giant cell (FBGC) are the fusion products of monocytic precursors, which are also the precursors of macrophages, (Brodbeck at al., 2002, Matheson et al., 2004) the presence of such leukocytes in the wound healing compartment may be of central importance in driving the tissue reaction to the material. No necrosis, tumorigenesis, or infection was observed at the implant site up to 18 months

antigenity and mild immune response (William et al., 2008).

slow (Skoglund et al., 1997, Jensen et al 1996, Klinge et al., 1992).

and Kuru, 1996, Yukna Ra and Yukna CN, 1998).

1st, 3rd, 6th ve 18th months.

(Figure 18-20).

Fig. 18. Remnants of the Xenograft (\*) surrounded by fibrous tissue at 30 days. A-T 4X.

Fig. 19. A dense, fibrovascular tissue (\*) in the side of ceraform implantation at 12th month M-T, 4X.

Fig. 20. Multinuclear giant cell (↔)in the implantation site. H-E, 40X

Histopatological Effect Characteristics of Various

0287-4547.

0142-9612.

3296.

Biomaterials and Monomers Used in Polymeric Biomaterial Production 441

Develioğlu H, Ünver Saraydn S, G. Bolayr, L. Dupoirieux. (2006). Assessment of the effect

Develioğlu H, Ünver Saraydn S, Laurent Duopoirieux, Zeynep Deniz Şahin. (2007).

Develioğlu H, Ünver Saraydn S, Ünal Kartal. (2009). The bone healing effect of a xenograft

Develioğlu H, Ünver Saraydn S, Ünal Kartal, Levent Taner. (2010). Evaluation of the long

Doherty MJ, Schlag G, Schwarz N, Mollan RA, Nolan PC, Wilson DJ. (1994).

Gauthier O, Bouler JM, Aguado E, Pilet P, Daculsi G. (1998). Macroporous biphasic calcium

Guillemin G, Meunier A, Dallant P, Christel P, Pouliquet JC, Sedel L. (1989). Comparison of

Guven O, Sen M, Karadag E, Saraydn D. (1999). A review on the radiation synthesis of

Handschel J, Wiesmann HP, Sratmann U, Kleinheinz J, Meyer U, Joos U. (2002). TCP is

Jensen SS, Aaboe M, Pinholt EM, Hjorting-Hansen E, Melsen F, Ruyter IE. (1996). Tissue

*Journal of Oral & Maxillofacial Implants,* Vol. 11, pp. 55-56, ISSN 0882-2786. Jeyanthi R., Rao KP. (1990). *In vivo* biocompatibility of collagen poly(hydroxyethyl methacrylate) hydrogels. *Biomaterials*, Vol. 11, pp. 238-243, ISSN 0142-9612. Karadag, E; Saraydn, D; Cetinkaya, S; Guven, O. (1996). In vitro swelling studies and

Karadag, E; Saraydn, D; Guven, O. (2004). Water absorbency studies of gamma–radiation

*Materials And Atoms*. Vol. 225, No. 4, pp. 489–496, ISSN 0168-583.

*And Chemistry*, Vol. 56, No. 4, pp. 381–386, ISSN 0969-806.

*Biomaterials*; Vol. 23, pp. 1689 –1695, ISSN 0142-9612.

*Biomaterials*, Vol. 17, pp. 67–70, ISSN 0142-9612.

*Biomedical Materials Research,* Vol. 77, pp. 627-631, ISSN 1549-3296.

*Research,* Vol. 80, pp. 505-508, ISSN 1549-3296.

*Implantology*. Vol. 36, pp. 167-173, ISSN 0160-6972.

University Pres, New York pp 124-132.

of a biphasic ceramic on bone response in a rat calvarial defect model. *Journal of* 

Histological findings of long-term healing of the experimental defects by application of a synthetic biphasic ceramic in rats. *Journal of Biomedical Materials* 

in arat calvarial defect model. *Dental Materials Journal,* Vol. 28, pp. 396-400, ISSN

term results of rat cranial bone repair using a particular xenograft. *Journal of Oral* 

Biocompatibility of xenogeneic bone, commercially available coral, a bioceramic and tissue sealant for human osteoblasts. *Biomaterials* Vol. 15, pp. 601-608, ISSN

phosphate ceramics: Influence of macropore diameter and macroporosity percentage on bone ingrowth. *Biomaterials*; Vol. 19, pp. 133–139, ISSN 0142-9612. Gold BG, Schaumburg HH. (2000). Acrylamide. In: Spencer PS, Schaumburg HH (eds)

*Experimental and clinical neurotoxicology*, 2nd edn. ISBN 0195084772, Oxford

corals resorption and bone apposition with two natural corals of different porosities. *Journal of Biomedical Materials Research,* Vol. 23, pp. 767-779, ISSN 1549-

copolymeric hydrogels for adsorption and separation purposes*. Radiation Physics* 

hardly resorbed and not osteoconductive in a nonloading calvarial model.

reaction and material characteristics of four bone substitutes. *The International* 

preliminary biocompatibility evaluation of acrylamide–based hydrogels

crosslinked poly (acrylamide–co–2,3–dihydroxybutanedioic acid) hydrogels. *Nuclear Instruments &Methods In Physics Research Section B–Beam Interactions With* 

A long-term study would be useful to evaluate the biological degradation behavior of the material utilized in this study. BCP ceramics are well known to be biodegradable due both to body fluid dissolution and bio resorption cellular activity Nery et al., 1990, Piatelli et al., 1996). It might indicate that the implants utilized in our studies are progressively resorbed, but the size of the particle might be big (Handschel et al., 2002) The studies reveal that Ceraform and xenograft are biocompatible. However, the materials did not promote bone formation.
