Synthetic Polymers, both organic and inorganic, are used in a wide variety of biomedical applications. The polymers can be biodegradable or nondegradable. Chitosan (CH), which is a naturally biodegradable, non-toxic biopolymer obtained by the deacetylation of chitin, has been demonstrated to have an intrinsic activity against a wide spectrum of bacteria, filamentous fungi and yeast. Several investigators have studied reinforced tricalcium phosphate (TCP), Chitosan, polymethylmethacrylate (PMMA)/methyl methacrylate (MMA) as potential cement. In fact addition of TCP with chitosan to the cement can improve biocompatibility and also enhance the mechanical properties of the cement because of its both biocompatibility and osteoconductivity properties. Crystalline phase and microstructure of the cement with hydroxyapatite - poly (methyl-methacrylate) were characterized by scanning electron microscopy (SEM; FEI Company), with the purpose to draw solid conclusions about the influence of the particles size, form and uniform mixing on the chemical process. We acquired PMMA sorted according to granulometric size.