COMPARATIVE CYTOTOXICITY ASSESSMENT OF TITANIUM PLATES ANODIZED WITH PHOSPHORIC ACID AND HYDROFLUORIC ACID AND Psidium guajava LEAF EXTRACT

Resumo

INTRODUCTION: Titanium is commonly used in implants, but the release of its ions can lead to cellular damage. Anodization forms a protective oxide layer, mitigating these effects. Nevertheless, conventional acid-based methods, while effective, pose environmental and
occupational safety challenges. OBJECTIVE: This study evaluates the cytotoxicity associated with using Psidium guajava leaf extract as an alternative anodization electrolyte. A comparative cytotoxicity assessment was performed between titanium plates anodized with conventional acids and those treated with Psidium guajava leaf extract. MATERIALS AND METHODS: The cytotoxicity of the extract was assessed in human osteosarcoma cells (Saos-2) and murine embryonic fibroblasts (NIH-3T3) cultured in DMEM supplemented with 10% FBS. An indirect assay was conducted in microplates using confluent cell monolayers incubated with extraction medium (EM) for 24 and 96 hours (37°C, 5% CO₂). The EM was obtained by immersing 1 cm × 1 cm titanium plates in culture medium for 24 hours at 37°C. As a negative control, only DMEM with 10% FBS was used. In the direct assay, cells were seeded directly onto titanium plates under the same conditions. Nonanodized titanium plates were used as negative controls. Cell viability was determined using the Neutral Red uptake assay. Statistical analysis was performed using ANOVA followed by Tukey’s post-hoc test (p ≤ 0.05). RESULTS AND CONCLUSION: Indirect assays showed that titanium plates anodized with different electrolytes maintained 100% viability (equivalent to the negative control) for both cell types and exposure times. Direct assays demonstrated that anodization increased cell viability by an average of 27,1%, with no
significant differences among electrolytes, cell types, or exposure times. This effect is attributed to the increased surface roughness of the biomaterial. According to ISO 10993-5 standards, biomaterials with cell viability equal to or greater than 70% are considered noncytotoxic. The observed results indicate that the use of aqueous Psidium guajava extract as an anodization electrolyte did not alter the cytotoxicity profile of anodized titanium, presenting itself as a promising alternative to conventional acids in this process.