There is only one good, biological way to correct crooked teeth, and that is with Orthodontic treatment, with braces. In its simplest form a dental brace consists of brackets, small entities bonded (glued) to the teeth. The brackets are connected to a wire along which the teeth are being moved.
The advantages of using braces to correct crooked teeth are:
It gives the healthiest result.
Once the Orthodontic treatment has been done, there is no maintenance needed.
In order to minimize the risk for a relapse, once the teeth have been straightened, a very thin metal wire (retainer) is bonded (glued) behind the front teeth in each jaw that has been treated.
A possible disadvantage with having Orthodontic treatment (wearing dental braces) is the time factor. In general, one can say that the more crooked your teeth are the longer time is needed to properly align the teeth. Also, in general, Orthodontic treatment takes somewhat longer in adults, because the jaw bone is harder (more mineralized).
Although today it is much more common to see adults with braces, there are still those who hesitate for pure aesthetic reasons. If that is the case, the Orthodontist can use a wire covered with white plastic. The Orthodontist can also use gold plated brackets or porcelain (ceramic) brackets.