CYTOTOXICITY AND GENOTOXICITY ASSESSMENT OF SURFACE COATINGS ON TITANIUM DENTAL IMPLANTS

Background: Titanium dental implants are widely used in restorative dentistry due to their biocompatibility and
mechanical properties. Surface coatings enhance osseointegration and antimicrobial effects but may introduce
cytotoxic and genotoxic risks.
Objective: To evaluate the cytotoxicity and genotoxicity of three common surface coatings—hydroxyapatite (HA),
titanium nitride (TiN), and zirconia (ZrO₂)—on titanium dental implants.
Methods: Titanium discs (n=120) were divided into four groups: uncoated (control), HA-coated, TiN-coated, and
ZrO₂-coated. Cytotoxicity was assessed via MTT assay and lactate dehydrogenase (LDH) release in human gingival
fibroblasts (HGFs) and osteoblast-like cells (MG-63) at 24, 48, and 72 hours. Genotoxicity was evaluated using comet
assay and micronucleus test. Statistical analysis included ANOVA and Tukey’s post-hoc tests (significance: p < 0.05).
Key Findings: HA coating showed the highest cell viability (92.5% ± 2.1 in HGFs at 72 hours) and lowest LDH
release (8.3% ± 1.2). TiN exhibited moderate cytotoxicity (viability: 78.4% ± 3.0; LDH: 18.7% ± 2.5). ZrO₂ had the
lowest viability (65.2% ± 4.1) and highest LDH release (25.6% ± 3.2). Genotoxicity was negligible for HA (comet tail
moment: 1.2 ± 0.3; micronuclei frequency: 0.8% ± 0.2) but significant for ZrO₂ (tail moment: 8.7 ± 1.5; micronuclei:
4.5% ± 0.7; p < 0.001).
Conclusion: HA coating demonstrated superior biocompatibility, while ZrO₂ induced notable cytotoxic and genotoxic
effects. TiN showed intermediate results. These findings emphasize the importance of coating selection for clinical
safety.