Objective

Titanium dioxide (TiO₂) incorporation in biomaterials is a promising technology due to its photocatalytic and antibacterial activities. However, the antibacterial potential of different TiO₂ crystalline structures on a multispecies oral biofilm remains unknown. We hypothesized that the different crystalline TiO₂ phases present different photocatalytic and antibacterial activities.

Methods

Three crystalline TiO₂ films were deposited by magnetron sputtering on commercially pure titanium (cpTi), in order to obtain four groups: (1) machined cpTi (control); (2) A-TiO₂ (anatase); (3) M-TiO₂ (mixture of anatase and rutile); (4) R-TiO₂ (rutile). The morphology, crystalline phase, chemical composition, hardness, elastic modulus and surface free energy of the surfaces were evaluated. The photocatalytic potential was assessed by methylene blue degradation assay. The antibacterial activity was evaluated on relevant oral bacteria, by using a multispecies biofilm (Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum) formed on the treated titanium surfaces (16.5 h) followed by UV-A light exposure (1 h) to generate reactive oxygen species production.

Results

All TiO₂ films presented around 300 nm thickness and improved the hardness and elastic modulus of cpTi surfaces (p < 0.05). A-TiO₂ and M-TiO₂ films presented superior photocatalytic activity than R-TiO₂ (p < 0.05). M-TiO₂ revealed the greatest antibacterial activity followed by A-TiO₂ (≈99.9% and 99% of bacterial reduction, respectively) (p < 0.001 vs. control). R-TiO₂ had no antibacterial activity (p > 0.05 vs. control).

Significance

This study brings new insights on the development of extra oral protocols for the photocatalytic activity of TiO₂ in oral biofilm-associated disease. Anatase and mixture-TiO₂ showed antibacterial activity on this oral bacterial biofilm, being promising surface coatings for dental implant components.

中文翻译：

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口腔多物种生物膜中不同晶体TiO ₂相的抗菌光催化活性

客观的

由于其光催化和抗菌活性，将二氧化钛（TiO ₂）掺入生物材料中是一项很有前途的技术。然而，在多种物种的口腔生物膜上不同的TiO ₂晶体结构的抗菌潜力仍然未知。我们假设不同的结晶TiO ₂相表现出不同的光催化和抗菌活性。

方法

通过磁控溅射在商用纯钛（cpTi）上沉积三层TiO ₂结晶膜，以获得四组：（1）机械加工的cpTi（对照）；（2）A-TiO ₂（锐钛矿）；（3）M-TiO ₂（锐钛矿和金红石的混合物）；（4）R-TiO ₂（金红石）。评价了表面的形态，结晶相，化学组成，硬度，弹性模量和表面自由能。通过亚甲基蓝降解测定法评估光催化潜力。通过使用多种生物膜（血链球菌，内生放线菌和核纤梭菌）评估对相关口腔细菌的抗菌活性。）形成在处理过的钛表面上（16.5小时），然后用UV-A曝光（1小时）生成活性氧。

结果

所有的TiO ₂薄膜都具有约300 nm的厚度，并改善了cpTi表面的硬度和弹性模量（p <0.05）。A-TiO ₂和M-TiO ₂薄膜比R-TiO ₂具有更好的光催化活性（p <0.05）。M-TiO _2表现出最大的抗菌活性，其次是A-TiO ₂（分别减少了约99.9％的细菌和99％的细菌）（相对于对照，p <0.001）。R-TiO ₂没有抗菌活性（相对于对照，p> 0.05）。

意义

这项研究为口腔生物膜相关疾病中TiO ₂的光催化活性的额外口腔方案的发展带来了新的见识。锐钛矿和TiO ₂混合物对该口腔细菌生物膜具有抗菌活性，是用于牙科植入物组件的有前途的表面涂层。