Hello, It is hard for me to give you an accurate explanation as to why you have a power chain, without being able to see your case. The best way to find an accurate answer is to ask your orthodontist, since they have been overseeing your case. They can reassess your case, make any adjustments that are needed and give an accurate explanation for using the power chain. Cheers!
Continue to wear your retainer as directed by your orthodontist. The teeth at the site of the crack can drift apart, causing spacing to develop or they can become crowded in that area. Ideally, a new retainer would need to be made to make sure no issues develop, but I understand that finances always play a role in orthodontic treatment. I would make sure that if you cannot afford a new retainer, that you continue to see your orthodontist at regular intervals so they can verify that no changes have occurred at the site of the crack.
Retainers provide your tissues and teeth time to adjust to their new positions after orthodontic treatment has been completed. Active retainers can close spaces only if the teeth have shifted very minimally after treatment. You would need to wear your retainers day and night until the space is closed and then continue wearing them every night to keep the space closed. If your teeth have moved considerably, you can go for a short re-treatment, if it is needed.
