## 4 Discussion
Additionally, the appropriate mechanical properties can positively influence cellular behavior, promoting the differentiation of stem cells into osteoblasts--the cells responsible for forming new bone tissue [1; 4; 9; 37; 42]. The use of ceramic materials such as CaP, particularly TCP, BCP, and HA, in regenerative processes for critical defects in large animals is extensively documented in the scientific literature [42; 43]. This aligns with the findings of this review, as most studies opted for the use of scaffolds made from these biocearamics. Due to their composition being similar to bone, they exhibit excellent biocompatibility and good osteoconductive and regenerative properties, promoting effective integration [5], which justifies their widespread use. In particular, TCP has a controlled degradation rate that can be adjusted to match the rate of bone formation [43]. Comparing the different compositions of scaffolds and their relationship with the inflammatory response (secondary outcome), scaffolds composed of CaP in various ratios [28] exhibit a low inflammatory response characterized by osteoclasts aiding in material degradation. On the other hand, scaffolds containing \(\beta\)-TCP [36] demonstrate a high potential for bone formation, particularly when combined with additional treatments, such as recombinant bone morphogenetic protein (rhBMP2) or mesenchymal stem cells (MSCs), despite potentially triggering a moderate inflammatory response. Some cases [35] mention an association between chronic inflammatory reactions and the use of certain materials (e.g., \(\beta\)-TCP [33]). [PERSON] et al. (2006) [28] observed biodegradation without significant inflammation associated with calcium phosphate (CaP) microparticles. Many reviewed studies [29; 30; 33; 35] do not provide explicit details on the inflammatory reaction, instead focusing more on bone formation and the overall biocompatibility of the scaffolds. The results found in this review show that \(\beta\)-TCP scaffolds were frequently associated with better bone formation outcomes. The addition of cells or growth factors also improved the results. [PERSON] et al. (2006) [29] and [PERSON] et al. (2007) [35] utilized \(\beta\)-TCP scaffolds with different sizes and porosities. Both showed good bone regeneration; however, the combination of \(\beta\)-TCP with other materials, such as cells [29; 35], resulted in better bone formation than pure \(\beta\)-TCP, suggesting that the type of cell or the combination with the scaffold may influence bone regeneration. [PERSON] et al. (2021) [26] reported that PLGA/TCP scaffolds exhibited callus formation and low peripheral bone density. TCP scaffolds maintained their structure but were more infiltrated with fibrous tissue and blood vessels. This suggests that material combinations can affect the structure and quality of regenerated bone. [PERSON] et al. (2021) [27] reported effective bone regeneration with HA/TCP in combination with different treatments (dental pulp neural crest mesenchymal stem cells (DPNCCs) and bone marrow aspirate (BMA)). [PERSON] et al. (2022) [32] and [PERSON] et al. (2019) [30] also utilized BCP, demonstrating its effectiveness in promoting bone formation. Notably, [PERSON] et al. (2019) [30] observed greater mineralization compared to HA. In addition to the material used in fabrication, the macro- and micro-characteristics of scaffolds significantly influence their behavior. The geometry of the scaffold can influence its integration with the host tissue and the colonization of cells within its structure. Porosityis crucial for vascularization and cellular growth within the scaffold [17]. Larger pores can facilitate the entry of nutrients and cells, while smaller pores may be more effective in retaining cells [1]. Structurally, the scaffold needs to be porous, featuring an interconnected network of pores with an appropriate pore size.