Hello,
Let me answer one by one -
1.According to the expert orthodontists, the critical period is right after the treatment & the teeth trying to adapt to the new position .
So during this period Retainers should be placed.
2. They may be of removable or may be fixed depending on the type of teeth & jaw position & other factors to last for longer periods .
3.They may be of metal or plastic .
Next Steps
consult orthodontist for further details.
Health Tips
after care with retainers is also important to maintain your Smile & oral health
Thanks!