With tooth decay can usually straighten teeth, tooth decay has little effect on straightening teeth. 1. Orthodontics and whether there are cavities actually has no greater relationship, if the front teeth have cavities, try to choose to repair, will affect the aesthetic, if the middle back teeth (premolar) have cavities, according to the orthodontic need to remove cavities, therefore, there are cavities usually can be straightened teeth. 2. It is not that you can’t straighten your teeth if you have cavities, but the treatment plan will be different compared to the normal situation, and you have to repair or remove the cavities first. Orthodontic treatment is a complicated process and requires a visit to the hospital for examination before a plan for orthodontic treatment can be formulated. If you have tooth decay, you should eat less sweets and stimulating foods, you need to pay attention to oral hygiene, and if you have other uncomfortable symptoms, you should consult a doctor for examination.