Loose teeth over time are often due to gum disease like Periodontitis, which weakens the supporting bone and makes chewing difficult; you should see a dentist for cleaning (scaling), possible gum treatment, and to assess if any teeth need stabilization or replacement, while maintaining good oral hygiene, quitting tobacco if applicable, and eating a soft, balanced diet to prevent further damage.

If you have a cavity, it should be treated first with a filling or root canal depending on severity, and for replacing extracted teeth, common options include dental implants (permanent and strong), bridges (fixed using nearby teeth), or removable dentures; a dentist will assess your gums and bone health to decide the best option, so consult a dental specialist to plan proper treatment and maintain good oral hygiene to prevent further decay.