In 2018, the 4 major goals of dental orthodontic treatment are proposed, namely health, aesthetics, function and stability. Failure cases that do not achieve these four goals are usually caused by 3 major reasons: improper program design, improper follow-up and force application, and improper selection of aligners. I. Improper program design In orthodontics, whether it is the traditional aligners, or the non-retaining bracket aligners that can be replaced by oneself, every step of teeth movement is carefully designed by the doctor, whether to extract the teeth or not, whether to use the implant nails or not, or even the distance of the teeth movement in millimeters, are all within the plan, therefore, some inappropriate program design predicts the failure of orthodontics from the beginning, and it will bring the corresponding harm, and some of them are even irreversible. The damage, some even irreversible. 1.Teeth should be extracted but not extracted The cases that need to be extracted are “more teeth and less bone”, such as severe crowding and anterior protrusion, we can increase the amount of bone, such as expanding the arch, pushing the molar teeth backward, or “reduce the teeth”, such as extracting the teeth, slicing and cutting. However, for every 1mm of crowding, 1mm of arch space is needed, and for 1mm of anterior recession, 2mm of arch space is needed. Expansion of the arch, push grinding teeth distance is limited, if you know that you can not put, but also insist on alignment, there will be a “neat buck teeth” or the results of unstable and easy to relapse adverse consequences. 2, should not be extracted but extracted teeth If the amount of bone and teeth can be coordinated, but extracted teeth, there will be a gap between the teeth, can not close the gap of the situation, the same orthodontic results are also unstable. There are some specific people, such as 35 + women, in the collagen loss of the additive effect, there will also be face collapse or braces face problems, more terrible is that these situations are irreversible. 3, alignment and bite out of sync Orthodontics always puts health in the first place, the upper and lower teeth can achieve a good cusp and fossa relationship, muscle joint tissues will be comfortable. The second most important goal of orthodontic treatment is aesthetics, and alignment is the most basic requirement for aesthetics. In some cases, the teeth are aligned, but there are problems with the occlusion, pointed relative to the muscles and joints will be sore, and the impact on the whole body is also quite large. 4, cause serious joint disease Orthodontics, if the doctor only considered the teeth alignment and ignored the function, it is likely to cause temporomandibular joint dysfunction, opening popping, pain and other problems, which is one of the bad results. Second, inappropriate follow-up plus force Every follow-up, the doctor has to force the braces, if the force is too much, there may be gum swelling, root resorption, and even loose teeth, which has the reason that the doctor’s judgment of the patient’s periodontal force tolerance is wrong, but also the reason that the patient increases the force on his/her own, such as in order to end the treatment quickly, the patient does not hang the band according to the doctor’s instructions, and increase the number of bands by himself/herself. Third, improper selection of orthodontic appliances 1, the bracket often fall off the traditional orthodontic appliances, rely entirely on the bracket fixed arch wire to achieve, frequent bracket fall will affect the teeth to move, thus affecting the progress of orthodontic treatment, too long a period of time, will increase the risk of root resorption and teeth loosening. Some patients’ wrong jaw situation or dietary habits lead to a much higher risk of bracket fall than other patients, if the doctor predicts this situation, he can guide the patient to choose a more suitable braces to avoid this kind of situation. 2, invisible bracket wearing time is not enough Unlike traditional bracket, the key to the success of the invisible bracket is to wear the braces correctly and at the right time, not enough time to wear the braces every day will also affect the progress of the treatment, and sometimes even have to be converted to traditional bracket to continue to complete the treatment. For example, if some groups who often need to socialize and socialize have long meal times and need to wear braces frequently every day, which can’t give the teeth a long-lasting and stable force, the doctor should recommend them to use lingual braces or single crystal or ceramic fixed braces, which are both aesthetically pleasing and can guarantee the treatment effect. Although after orthodontic relapse, we can still have a second orthodontic treatment, but many of the damage caused by the undisciplined orthodontic program is irreversible, the second orthodontic treatment can only improve, can not achieve a more ideal treatment effect, so we must choose an experienced and skilled orthodontist before orthodontic treatment, to reduce the risk of orthodontic failure from the source.