Bone Formation and Anti-Inflammatory Properties of Iodine-Loaded Titanium Implants: An Animal Study

Titanium implants are subjected to various surface treatments to improve their in vivo function. In this study, we evaluated the usefulness of titanium implants treated with acid, NaOH, CaCl₂, heat, and ICl₃ (Ac-NaCaThIo) in terms of in vivo bone-bonding strength, bone formation, and histological anti-inflammatory properties. Iodine-loaded experimental dental implants and commercial control dental implants were placed in rabbit femurs, and bone-bonding strength was evaluated by measuring the implant stability quotient (ISQ), bone formation using tissue specimens, and the effect of iodine using thyroid-stimulating hormone (TSH) levels. Iodine-loaded titanium plates and untreated titanium plates were placed on rat skulls and inoculated with Streptococcus mitis (S. mitis) solution to evaluate anti-inflammatory properties. Consequently, the experimental implants did not demonstrate non-inferiority in bone-bonding strength (ISQ) compared with the controls; however, histological specimens revealed dense bone contact and favorable bone formation. TSH levels showed no differences at 13 weeks, indicating no long-term adverse effects of iodine. The experimental tissue specimens of the soft tissue had fewer inflammatory cells than the control at 2 weeks after placement, demonstrating an anti-inflammatory effect. These results suggest that, although non-inferiority in ISQ was not demonstrated, Ac-NaCaThIo-treated implants showed favorable bone formation, dense bone contact, anti-inflammatory properties, and biosafety, indicating potential for future applications.