China now boasts seven of the 10 longest bridges in the world, all built within the past decade. Such engineering feats were once mainly the province of the United States, which for much of the latter half of the 20th century boasted most of the longest bridges in the world. Here are the 10 longest bridges in the U.S., and no matter how well traveled you are, four or five of these bridges will come as a surprise.
There are two types of neck braces: soft and rigid. A soft cervical collar is made from thick foam rubber covered in cotton. It is used to support your neck and control pain after an injury (e.g., whiplash).
Retainers are fitted at the end of orthodontic treatment after the braces are removed. They can be either removable or fixed onto the teeth. There are different types of retainers. The choice of retainer is affected by a number of different factors and your orthodontist will explain which retainer is best for you. Sometimes you will be recommended to wear more than one type of retainer to reduce the chances of the teeth relapsing. Types of retainers. There are lots of different types of retainers. The commonest types of retainers used in the UK are the vacuum-formed retainer, the bonded retainer and the Hawley retainer.