There is no optimal age for cosmetic dentistry, and it is recommended to start at around 12 years old. 1. At present, there is no age limit for cosmetic dentistry, you can also have cosmetic dentistry when you are an adult and feel that your face value is affected by the deformity of your teeth, and if you have the need for cosmetic dentistry, you can have it done at any time, and there is no need to be limited by age. 2. It is generally recommended to start straightening teeth at the age of 12, at the age of 12, all the permanent teeth have grown out, but the alveolar bone has not been fully developed and finalized, at this time to start straightening teeth, you can achieve twice the result with half the effort. After adulthood, the alveolar bone has already been shaped, the time to carry out cosmetic surgery is longer, the treatment is more difficult. If you have the need for teeth straightening, you can go to the stomatology department of a regular hospital for examination first to understand the specifics of teeth straightening.