Q: I have a crown that is screwed into an implant that has spun loose three times. My dentist just keeps tightening the screw. Is this normal? JR in West Palm Beach

A:  We all have a few loose nuts in our families, but you should not be one of them. My cousin Ira in Vegas comes to mind.

The implant fixture is the root-shaped cylinder that stays anchored in the jaw bone. The abutment is the post that connects the crown to the implant. Sometimes the small screw that attaches the abutment to the implant will reverse itself (“righty tighty; lefty loosey”) causing the crown to rotate and loosen. Many times a new crown is needed.

To prevent this from happening, your DDS can flow some composite resin “goo” onto the hex-shaped screw head, locking the screw in place as the resin hardens, then proceed to make the crown.