Because nanoparticles have particular characteristics, such as small size and surface effects, nano-TiO₂ is widely used in air purification, wastewater treatment and self-cleaning. In recent years, TiO₂ photocatalysis has thoroughly explored as a new titanium implant surface treatment method. Photocatalytic performance is better for TiO₂ nanowires than for nano-TiO₂ particles. Hence, these nanowires have received widespread attention with regard for their more specific surface area and surface energy, improved charge carrier transport efficiency, and enhanced charge collection efficiency. Photon-generated carrier transport moves in a one dimensional straight path along a nanowire, and this could decrease photoelectron loss. In this paper, we summarized the principles underlying, factors that influence, and applications involving TiO₂ nanowire photocatalysis. Additionally, we describe its method of preparation and toxicity.

Dental implant restoration is an effective way to restore the chewing and aesthetic function for edentu-lous. However, dental implant restoration is facing great challenges of the lack of available bone, the maxillary sinus or inferior alveolar nerve vascular bundle, which is often necessary to carry out the related bone augmentation operation. All-on-Four technique is to use four implants in the anterior part of complete edentulous jaws, the two most anterior implants are placed axially whereas the two posterior implants are placed distally angled, to support a provisional, fixed,and immediately loaded prosthesis. The technique avoids the artificial bone substitutes implantation and maxillary sinus augmentation or other bone augmentation surgery. Besides, it could alleviate patients' psychological reaction, postoperative reaction, as well as time and money costs. It is considered a feasible treatment method to combine the application of the oblique implant and the axial implant in the treatment of the edentulous patients. This paper will elaborate on the concept of All-on-Four, the conventional technology, the evaluation research and some new viewpoints.

The standardized workflow of computer-aided static guided implant surgery includes preoperative examination, data acquisition, guide design, guide fabrication and surgery. Errors may occur at each step, leading to irreversible cumulative effects and thus impacting the accuracy of implant placement. However, clinicians tend to focus on factors causing errors in surgical operations, ignoring the possibility of irreversible errors in nonstandard guided surgery. Based on the clinical practice of domestic experts and research progress at home and abroad, this paper summarizes the sources of errors in guided implant surgery from the perspectives of preoperative inspection, data collection, guide designing and manufacturing and describes strategies to resolve errors so as to gain expert consensus. Consensus recom-mendation: 1. Preoperative considerations: the appropriate implant guide type should be selected according to the patient′s oral condition before surgery, and a retaining screw-assisted support guide should be selected if necessary. 2. Data acquisition should be standardized as much as possible, including beam CT and extraoral scanning. CBCT performed with the patient′s head fixed and with a small field of view is recommended. For patients with metal prostheses inside the mouth, a registration marker guide should be used, and the ambient temperature and light of the external oral scanner should be reasonably controlled. 3. Optimization of computer-aided design: it is recommended to select a handleguided planting system and a closed metal sleeve and to register images by overlapping markers. Properly designing the retaining screws, extending the support structure of the guide plate and increasing the length of the guide section are methods to feasibly reduce the incidence of surgical errors. 4. Improving computer-aided production: it is also crucial to set the best printing parameters according to different printing technologies and to choose the most appropriate postprocessing procedures.