Traditional fixed braces are usually brackets made of metal, and there is also a type of ceramic brackets that have an invisible effect and are more expensive. Advantages: Among the various orthodontic methods, this type of braces has the best effect on the fine adjustment of teeth as well as the occlusal relationship. Disadvantages: In addition to affecting the aesthetics during the correction period, if you don’t pay attention to oral hygiene during the correction process, it will cause decalcification of the tooth surface or even caries on the edge of the bracket, and the tooth surface may leave traces after removing the bracket, which affects the aesthetics. Urumqi Stomatology Hospital Orthodontics Yuan Fang 2, invisible braces This type of orthodontic treatment has been carried out for more than ten years, due to the non-use of brackets and is called “invisible braces”. The specific orthodontic method is to take the teeth model, and then use the computer to simulate the process of teeth movement during orthodontic treatment to design a series of (generally about 10-40) plastic transparent braces. They are worn for 20 hours a day and are only removed for meals. Since the plastic braces are hard and flexible enough, they are used to adjust the teeth in a predetermined direction. Every two weeks, the braces are replaced with a new one in sequence until the teeth are aligned to the desired position. The length of the treatment depends on the degree of irregularity of the teeth. Advantages: Because the plastic is transparent, wearing almost does not affect the aesthetics, the use of this technology in the United States is very high, which is also related to the American “dental culture”, they have a high demand for straight teeth, but whenever there is a little irregularity in the teeth, many people will choose to go to the orthodontic treatment. Disadvantages: the cost is more expensive; the doctor can not participate in the adjustment of the teeth, the effect of its orthodontic treatment is completely dependent on the level of production of braces, still belongs to the movable orthodontic appliances, the three-dimensional control of the teeth of the accuracy is far lower than that of the fixed orthodontic appliances, and therefore is only suitable for mild irregularities of the teeth, the degree of dental irregularities of the serious people are not very suitable for the technology. 3.Lingual Fixed Aligner The appearance and principle of this kind of aligner is close to the traditional fixed aligner, however, its brackets are glued on the inner side of the teeth, which will not be seen when you speak, and it has the effect of “completely invisible”. Lingual braces have been around since the 1970s and have become more sophisticated. With the help of computer-aided design, it is customized according to the condition of each patient’s teeth, which greatly improves the accuracy of orthodontic treatment, and the effect can be comparable to that of traditional braces. Advantages: good orthodontic effect, invisible effect is the best, can be completed without the knowledge of the onlookers, especially suitable for the people who have a high demand for aesthetics during the correction. Disadvantages: High cost. Due to sticking on the inner side of the teeth, it is difficult to clean, and the foreign body sensation of the tongue is strong, which is difficult to be accepted by individual sensitive people.