Characterization and Evaluation of In Vitro Biocompatibility of Acid-Etched Titanium

Biological events related to osseointegration may be affected by physical and chemical features of implant surface. Objectives: The aim of this study was to characterize an acid-etched surface of commercially pure titanium (cpTi), and investigate its in vitro biocompatibility. Methods: cpTi discs were treated with H₂SO₄/HCl and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Discs without treatment were used as a control. Biocompatibility was evaluated using human osteoblasts derived from alveolar bone. Osteoblasts were cultured in supplemented α-MEM at a concentration of 2 x 10⁴ cells/well on cpTi discs in 24-well culture plates and incubated at 37ºC and 5% CO₂. At 7, 14, and 21 days, cell proliferation, viability, total protein content, and alkaline phosphatase (ALP) activity were evaluated. Bone-like nodule formation was evaluated at 21 days. Data were compared by ANOVA or Mann-Whitney, when appropriate. Results: Treatment with H₂SO₄/HCl produced a cpTi surface of bigger topographical irregularity compared to cpTi without treatment as observed by SEM and AFM. Proliferation (P=0,14), viability (P=0,53), total protein content (P=0,17), and ALP activity (P=0,34) were not affected by surface treatment. Bone-like nodule formation was reduced on acid-etched surface compared to surface without treatment (P=0,01). Conclusions: This study showed that cpTi surface topography was altered when treated with H₂SO₄/HCl, and this treatment affected the in vitro biocompatibility of cpTi, reducing bone-like nodule formation.