Whether we have had orthodontic treatment or not, whether our teeth were straight to start with or not, many of us find our teeth move further out of position over time.
This is often most noticeable in the late teens and early twenties, but there is no age generally where healthy teeth lose the potential to move. Thorough diagnosis and careful treatment of your bad bite will reduce the chances of movement later but even this attention to detail will not totally get rid of the risk of changes in your bite over time.
The most predictable way orthodontists have at this stage of keeping teeth in the best looking positions is to encourage patients to actively participate in guiding their teeth for as long as they would like to keep their teeth in good positions. You will be given a retainer programme that is specifically designed for your bite to help you reduce the risk of changes in tooth position for as long as you wish to keep the teeth in a good position.