RESUMO
Photocatalysts have attracted attention in the medical field for their antibacterial effects. However, typical photocatalysts are activated by ultraviolet rays, which may have adverse effects. Therefore, we focused on a new photocatalyst that is activated by visible light, hydroxyapatite (HAp), and amino acid complex with gray titania, and evaluated its antibacterial effects against Porphyromonas gingivalis and effect by toothbrushing. The test sample was a titanium alloy substrate, and four surface treatments were applied: (1) substrate only, (2) substrate with HAp complex, (3) substrate with HAp complex with gray titania, and (4) HAp-tryptophan complex with gray titania (TR). These surface treatments were evaluated with or without toothbrushing (8 total groups). Surface roughness (Sa), fluorescent X-ray analysis (XRF), and scanning electron microscopy (SEM) were used to evaluate surface properties. To investigate antibacterial effects, each sample was seeded with P. gingivalis, irradiated with red light, and total viable bacterial count was determined. For Sa measurement, TR showed no significant difference after toothbrushing. However, in XRF and SEM observation, TR exhibited peeling of the applied coating after toothbrushing. In the antibacterial test, TR showed a decrease in P. gingivalis under no toothbrushing condition. Conversely, with toothbrushing, the TR coating appeared to peel. However, no significant difference in P. gingivalis count was observed among all groups. HAp-tryptophan complex with gray titania coating showed an antibacterial effect against P. gingivalis when irradiated with visible light. However, toothbrushing can result in coat peeling and consequently reduce the antibacterial effect.
Assuntos
Durapatita , Titânio , Antibacterianos/farmacologia , TriptofanoRESUMO
Hydroxyapatite particles (HAp) have been widely used by many dental implant systems as an implant coating material because of their osteoconductive properties. This study aimed at improving the antibacterial effect of HAp as a substitute for antibiotic agents which can increase drug resistance. HAp/gray titania was selected as the coating material for on the titanium alloy substrate due to its antibacterial properties after photocatalytic reaction. When combined with amino acids, HAp can form a fluorescent complex which enhances this property. Before clinical application, this new coating should be examined for cytotoxic effects against biological cells or tissues. Therefore, L929 mouse fibroblasts were used to represent fibrous tissue surrounding dental implant. After performing a 6-day alamarBlue assay, the new coating method using hydroxyapatite-tyrosine complex with gray titania on titanium alloy surface can be said to have no influence on the growth of fibroblasts.
