磷酸蚀刻增强纳米坑TiO 2表面亲水性

Our research group developed a novel nano-pitted (NP) TiO2 surface on grade 2 titanium that showed good mechanical, osteogenic, and antibacterial properties; however, it showed weak hydrophilicity. Our objective was to develop a surface treatment method to enhance the hydrophilicity of the NP TiO2 surface without the destruction of the nano-topography. The effects of dilute and concentrated orthophosphoric (H3PO4 ) and nitric acids were investigated on wettability using contact angle measurement. Optical profilometry and atomic force microscopy were used for surface roughness measurement. The chemical composition of the TiO2 surface and the oxidation state of Ti was investigated using X-ray photoelectron spectroscopy. The ccH3PO4 treatment significantly increased the wettability of the NP TiO2 surfaces (30◦ ) compared to the untreated control (88◦ ). The quantity of the absorbed phosphorus significantly increased following ccH3PO4 treatment compared to the control and caused the oxidation state of titanium to decrease (Ti4+ → Ti3+). Owing to its simplicity and robustness the presented surface treatment method may be utilized in the industrialscale manufacturing of titanium implants.

Surface roughness and hydrophilicity have long been known as two key properties that promote the osseointegration of titanium implants [1]. This idea is supported by a wide range of high-quality scientific data that revealed the correlation between either microor nano- roughness or wettability and the biological properties of titanium-dioxide (TiO2) surfaces [2]. However, the transferability of the scientific achievements from experimental settings into industrial-scale manufacturing is often limited by the low productivity of the underlying technologies. Our research group has previously developed an electrochemical surface treatment method that enables the reproducible production of a novel nano-pitted (NP) TiO2 surface on grade 2 titanium discs and dental implants that showed good mechanical, osteogenic, and antibacterial properties [3,4].

Various methods have been proposed to enhance the hydrophilicity of titanium implants, including but not limited to UV irradiation, gamma irradiation, and thermal treatment. Each of these methods have disadvantages that detrimentally affect their applicability in the industrial-scale manufacturing of implants. For example, several studies have been published touting the benefits of UV irradiation that temporary turned dental implant surfaces to super hydrophilic, albeit they returned to a hydrophobic state in the dark [5]. Ueno et al. argues in favor of gamma-irradiation to regain the hydrophilicity and bioactivity of titanium implants that are lost over time owing to hydrocarbon deposition from the atmosphere [6]. However, a 25–35 kGy dose of gamma irradiation, which is generally used for the sterilization of titanium implants, might cause irreversible alteration to the TiO2 nanosurfaces as has been the case in other nanoparticles of various materials [7,8]. Thermal treatment can also temporarily increase the hydrophilicity of titanium implants, but the effect often decreases over time, and the heat may modify the surface morphology [9,10].

Fig1

The mean, standard deviation, and coefficient of variation were used from the descriptive statistics. The coefficient of variation (CV) is the normalized standard deviation (standard deviation divided by the mean). The CV value under 10% means a homogenous dataset, between 10 and 20% means a low heterogenous dataset, and between 20 and 30% means a very heterogenous dataset. Above 30%, the dataset is very volatile.

A Kruskal–Wallis test was performed to compare the samples (p < 0.05) and a GamesHowell test for the post hoc comparison. The Games-Howell test was deliberately selected for post hoc analysis because it was nonparametric, unlike the Tukey’s test, and it did not assume equal sample sizes and homogeneity of variances.