Orthodontics is the dentistry discipline dealing with malocclusions, which is commonly known as straightening of teeth. It is focused not only on improving the aesthetics of a smile, but also on the functional conditions of occlusion. Malocclusions are in fact a real threat to the health of masticatory apparatus, resulting in increased tooth decay, the development of periodontal disease (periodontitis) and disorders of the temporomandibular joints. Orthodontic treatment is carried out in both children and adults. The most common classification distinguishes between removable orthodontic appliances and fixed installations. The former is usually applied for children, and the effectiveness of this application depends to a considerable extent on the cooperation of the patient, i. e. whether the appliance is worn 16 hours a day. Fixed appliances can be glued to the lip facing surface or the inner tongue facing surface of the teeth (lingual appliances). There are two versions of fixed appliances depending on the material used for manufacturing - metallic or aesthetic (for example, made of porcelain or monocrystal). A nice smile is not just healthy and white teeth but also straight teeth.