Removable braces come in many different types, shapes, sizes and even colours. They are often mistakenly called retainers, but they are actually used to straighten teeth, correct bites and even lengthen the lower jaw in growing patients.
These types of removable braces are usually used for children either on their own, before they are fitted with metal fixed braces or sometimes at the same time. You can have one on its own that is worn on your top teeth which generically can be called an Upper Removable Appliance (URA) or you can have one on the bottom and one on the top which have acrylic blocks on either side, these are called Twin Blocks.
A URA will usually be used to move a section or one tooth only, so it doesn’t have the same advantages of the metal braces that straighten and correct every tooth. It is often used in children who don’t yet have all their adult teeth but their bite is having an adverse effect on their eating habits or potentially causing damage to other teeth. It may be used with fixed braces on the bottom to stop the top teeth biting down and breaking the fixed braces for a few months until the bite is better and fixed braces can be placed on the top. There are also URA’s that can help people stop sucking their thumb or finger, this is quite common and can severely affect the position of the teeth and cause them to protrude, which is why we sometimes intervene with orthodontics if someone is not able to stop on their own.
Twin Block’s can only be used while children and teenagers are still growing. It is used when there is a significant protrusion of the top teeth. It can be used as a single treatment on its own or as a first stage in a multiple appliance treatment. It works by using two (twin) blocks which are positioned on either side of the top and bottom brace that fit together when you bite down with your bottom jaw slightly pushed forward. This prolonged and continuous pushing the lower jaw forward encourages the lower jaw muscles to elongate. Meaning that the distance between the top and bottom teeth is reduced and the profile of the face improved. We sometimes use this on its own when a child’s teeth are straight but simply protrude so there is no need for fixed braces or if someone does not have enough adult teeth for fixed braces yet but the top teeth, because of their protrusion, are at risk of trauma (being hit or falling and damaged in the process). When used as the first step before fixed appliances are used, it is usually to improve the profile of the face and hopefully reduce the number, if any, teeth to come out as part of the treatment. As the only way to reduce this protrusion is with Twin Blocks and/or creating space to pull the top teeth back by having teeth removed.