With the development of implant technology, digital implant surgical guides have been used for precise implant position, angulation and depths of insertion, bringing great advantages such as shortening the operation time, reducing the risk of surgery, flapless implantation. Meanwhile, the disadvantages can't be neglected such as complicated production process, high cost, low precision etc. This article focuses on production, classification and accuracy of the digital implant surgical guide technology.

Long-term stability is an important part of orthodontic treatment and wearing a retainer is one of the methods to keep stable after active orthodontic treatment. Transparent film retainer and Hawley retainer are two kinds of retainer usually used in clinical treatment. the previous one is easy to made, comfortable and beautiful to wear, easily damaged. Hawley retainer is relatively complex to made and in a large size. And it is durable and adjustable. However, there are differences between these retainers on the retaining effects in different types of malocclusion. In clinical treatment, according to the type of malocclusion, we choose the appropriate retainer to keep stable occlusal relationship after orthodontic treatment.