## 4 Discussion  
For a successful osteoconduction, the 3D structure of a scaffold should support cell penetration and proliferation as well as neovascularization, enabling an adequate diffusion of nutrients to the new cells and preventing the failure of bone repair [4; 34; 35; 36; 37]. Moreover, scaffolds should present interconnected pores of sizes and morphologies adequate to ensure the diffusion of waste products out of the scaffold without interfering with other surrounding tissues [34]. It has been demonstrated that large pores (250-600 \(\upmu\)m) would increase scaffold permeability, cell colonization, as well as cell adhesion [14; 38]. A relatively good pore interconnectivity, however, causes a decrease in mechanical properties, namely loss of the compressive strength and elasticity modulus. On the other hand, higher pore interconnectivity would increase new bone formation within the scaffolds [14]. Moreover, osteoblasts and fibrovascular tissue seem to exhibit a preference for binding to biomaterials with pore sizes significantly larger than the own cell size [39]. An ideal bone substitute material for oral and maxillofacial use should mimic the structure of human trabecular bone, acting as a proper support for vascularization and bone ingrowth [36]. The newly developed composites evaluated in the present study showed high interconnectivity that lead to a larger surface area and greater fluid retention capacity than control group. All the scaffolds without collagen presented agglomerates \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{4}{c}{**Elastic Modulus (MPa)**} \\ \hline
**Groups (PLGA/HA + \(\beta\)-TCP)** & **Median** & **Minimum** & **Maximum** \\ \hline G1 (50/50) + Collagen & */** 18.6 & 16.7 & 23.8 \\ G2 (60/40) + Collagen & */** 28.3 & 26.7 & 40.6 \\ G3 (40/60) + Collagen & */** 22.8 & 21.9 & 24.5 \\ G4 (50/50) & 13.2 & 11.4 & 17.3 \\ G5 (60/40) & 15.4 & 13.8 & 18.6 \\ G6 (40/60) & 15.7 & 9.5 & 21.6 \\ Control Bio-Oss Block\({}^{\circledR}\) & * 2882.6 & 1808.6 & 3018.9 \\ \hline \multicolumn{4}{c}{Trabecular Bone [33]} & 1000 \\ PLGA [5] & & 2000 \\ \hline \hline \end{tabular} \({}^{*}\) The control group presented statistical difference with all the other groups. ** Groups G1, G2, and G3 presented statistical differences with groups G4, G5, and G6. [PLGA: polylactic-co-glycolic acid; HA + \(\beta\)-TCP: biphasic ceramic].  
\end{table} 
Table 4: Elastic modulus values in the composite and control groups. There was a statistically significant difference between the composites and control group. Moreover, statistical analysis revealed a significant difference in the elastic modulus between groups with (G1, G2, and G3) and without collagen impregnation (G4, G5, and G6). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{4}{c}{**Compression Strength (MPa)**} \\ \hline
**Groups (PLGA/HA + \(\beta\)-TCP)** & **Median** & **Minimum** & **Maximum** \\ \hline G1 (50/50) + Collagen & */** 1.5 & 1.32 & 1.83 \\ G2 (60/40) + Collagen & */** 1.91 & 1.78 & 2.22 \\ G3 (40/60) + Collagen & */** 1.62 & 1.51 & 1.82 \\ G4 (50/50) & * 0.96 & 0.84 & 1.02 \\ G5 (60/40) & * 1.01 & 0.89 & 1.67 \\ G6 (40/60) & * 1.15 & 0.76 & 1.29 \\ Control Bio-Oss Block\({}^{\circledR}\) & 0.34 & 0.17 & 0.46 \\ \hline \hline \multicolumn{4}{c}{Trabecular Bone [10]} & 2–10 \\ \hline \hline \end{tabular} \({}^{*}\) All presented a statistical difference with the control group. ** Groups G1, G2, and G3 presented statistical differences with groups G4, G5, and G6. [PLGA: polylactic-co-glycolic acid; HA + \(\beta\)-TCP: biphasic ceramic].  
\end{table} 
Table 3: Compressive strength values in the composite and control groups. There was a statistically significant difference between the composites and control group. Moreover, statistical analysis revealed significant differences in the compression strength between groups with (G1, G2, and G3) and without collagen impregnation (G4, G5, and G6).