Dental retainer is the means of special correction treatment that help achieve the final result of the orthodontic treatment. Let us see why it is necessary and why braces are not enough. We all know that a tooth has a crown and a root. We can see the crown, but we normally cannot see the root if it is not baring because of some disease. The jaw is the bone, so naturally the tooth root is surrounded by the bone tissue. But the tooth has no hard fixation on it. There is a little space between the tooth and the bone, the so-called periodontal hole. It contains the ligaments that hold the tooth on its place, and also nerves and vessels that provide it with nutritive elements.