## 4 Biocompatibility  
In the present review, only four authors reported biocompatibility tests. [PERSON] et al. [1] show that the silver nanoparticles and PMMA\(-\)AgNPs are biocompatible materials by using a comet  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline [PERSON] et al., 2018 (12) & Mixing PMMA in DMF and adding AgNO\({}_{3}\) solution & No & Inhibition zone test & UV-visible absorption, FTIR, TEM, FE-SEM & Acrylic resins for dentures \\ \hline [PERSON] et al., 2018 (8) & Mixing monomer with AgNPs with ultrasonic homogenizer & Cell counting with automated cell counter & Kirby-Bauer disk diffusion assay & DMA TGA, DSC, SEM imaging & Bone cement imaging \\ \hline [PERSON] et al., 2018 (2) & Mixing monomer with AgNP suspension & No & Inhibition zone test & Compression test, contact angle test, SEM imaging & Bone cement imaging \\ \hline \hline \end{tabular}
\end{table}
Table 1: _Cont_.  
Figure 2: Electronic Transmission Microscope (TEM) images of silver nanoparticles (TEM JEOL JEM-1010 60–80 kV, Digital micrograph 3.1 digital camera GatanBioscan 1k\(\times\)1k). Author’s own images.  
assay to evaluate genotoxicity and using an MTT assay and other testing methods as a cellular immunoassay (named BrdU assay) with a mouse monoclonal antibody. In their results, they find no statistically significant differences when comparing between PMMA discs with and without silver nanoparticles. They report spherically shaped AgNPs in a size range of 10 to 20 nm, and they used OptiCryl (New Stetic S.A., Antioquia, Colombia), a commercial PMMA denture base for forming discs, following the manufacturer's directions. [PERSON] et al. [8] evaluated biocompatibility by cell counting transgenic mouse osteoblast cell lines (TMOb) that were exposed to PMMA-AgNP composite bone cement, and they report no significant effect on the viability of the osteoblast cells. In this study, only cell viability was evaluated, although, as the authors mention, it is important to evaluate other parameters for biocompatibility in vitro, such as cell proliferation, and LDH test for further results. The authors report using the commercially available PMMA bone cement Palacos R (Heraeus Medical GmbH, Werheim, Germany) and AgNPs with a diameter between 30 and 50 nm, functionalized with poly(vinylpyrrolidone) (0.2% wt/wt). [PERSON] et al. [7] and [PERSON] et al. [9] evaluated cell viability in vitro by means of an MTT assay. [PERSON] et al. show a viability decrease in human bone marrow stromal cells (hBMSCs) grown on PMMA-Ag-coated wafers, depending on the laser pulses used when synthesizing PMMA-Ag using the pulsed laser deposition (PLD) method. They report that the use of 20,000 pulses decreased the viability of hBMSCs by 17%, compared with 10,000 and 14,000 pulses. They report AgNPs ranging in size from below 20 to 200 nm. On the other hand, [PERSON] et al. report no cytotoxic effects on an MC3T3-E1 preosteoblast cell line when they compared three different concentrations of silver nanoparticles encapsulated in oleic acid and mixed with a PMMA-based bone cement. AgNPs had an average diameter of \(5.3\pm 2.3\) nm. These results could indicate that the synthesis methods have affected the biocompatibility of the resultant materials; further studies are mandatory to test this position.