OVERDENTURES, can be a cost effective way to help with securing loose dentures with implants, significantly improving the retention and stability of dentures, especially full dentures. 

You can have as few as two and up to 6 implants. More implants increase stability and retention and 6 implants approaches the stability of "All on 4" and similar treatments but retains the advantage of ease of hygiene of a removable denture. 

See examples below