Why does the tooth shift during the day, and it hurts to put the nighttime retainer back?

Hello,

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Hope you are doing well. I thoroughly read your query and understand your concern. In orthodontic therapy, there are two phases, first is the active phase, wherein all the tooth movements are done, and alignment is achieved based on case requirements. Second is retainers therapy, wherein the movements done are held with the help of retainers. When the teeth are moved orthodontically, jaw bone undergoes changes with deposition of bone in some areas and removal of bone in other areas. This allows the teeth to travel to newer positions. Along with this, there are fibers that hold the teeth in a bone socket. After the teeth have moved to the new position, it takes about 10 to 12 months for the newly formed bone and fibers to mature. Once they mature, they hold the teeth in a new position, and the chances of teeth going back are reduced. For this reason, it is suggested to wear the retainers after orthodontic treatment for at least one year. I would suggest you wear the retainers on a full-time basis for at least 22 hours a day, similar to your Invisalign protocols. Remove it for oral hygiene activities and meal time. After about 8 to 10 months, you can slowly start reducing the wear-time to nighttime only. Followed by alternate nighttime wear and slowly off the retainers. After the treatment was completed, the teeth were in a new position, with the bone and fibers of the teeth still immature. Whilst you wear the retainers at night, your teeth are doing fine. But during the daytime, there were no restrictive forces on the tooth to hold on to the new position. Hence teeth tried to shift back. Again when you put retainers in the nighttime, teeth had already shifted on a microscopic level, and retainers tried to bring it again to new levels to a position where they were fabricated. Hence, it is hurting you. So, I would suggest you modify your retainers' wear-time protocols, and it should be better for you. Hope this resolves your doubts to some extent. Do reach out for further information or clarifications. Regards.