Why my lower denture with 2 implants keeps fall out?

If I understand your situation correctly, it sounds like your denture was initially very stable immediately after being attached to two dental implants.There were several possible causes for this type of situation. In the typical situation, there are attachments that sit on the inside of the denture and snaps on to the dental implant so that the denture becomes attached to it. If this attachment becomes dislodged or distorted, then the denture will no longer have a tight attachment to your implants. a second, and less likely possibility is that the component that gets screwed into the implant has gotten loose or is missing entirely. Your dentist can very easily correct either one if these situations. I hope hope you found this information helpful,Dr Champagne

Sounds like the implant attachments need to be adjusted for a tighter fit. It should be an easy adjustment as long as everything else is ok.

The technique of holding a denture over 2 implants, on my personal point of view its not enough (because of all the pressure from your mouth that is received just by 2 dental implants). At least try 4 for more stability, now if you do not want them to be removable, then 5 or 6 are the solution, that can help you up,and it would be screw retained bridge. An All on 6, could be your solution. Hope this helps.