Prof Maged Younes, Chair of EFSA’s expert Panel on Food Additives and Flavourings (FAF), said: “Taking into account all available scientific studies and data, the Panel concluded that titanium dioxide can no longer be considered safe as a food additive . A critical element in reaching this conclusion is that we could not exclude genotoxicity concerns after consumption of titanium dioxide particles. After oral ingestion, the absorption of titanium dioxide particles is low, however they can accumulate in the body”. 

Unfortunately, we studied that all of the above methods are employed after machining or forming, and they require a long process chain and costly production types of equipment [21–24]. Therefore, we proposed a titanium alloy implant preparation process that integrated with cutting and surface modification. The oxygen-rich atmosphere increases the partial pressure of oxygen in the oxidizing environment, and the heat generated during the cutting process increases the temperature and the rate of the oxidation. It uses the cutting heat and oxygen-rich atmosphere generated during the cutting process to form the oxide film (TiO₂) to improve the corrosion resistance of the titanium alloy. The experimental equipment is shown in Figure 2. Since the cutting temperature is the most important factor in the oxide film formation process, this paper carried out researches based on theoretical analysis and experimental investigation to acquire an ideal temperature range for the cutting process to achieve the oxide layer.