Do your screws stop loosening after the titanium bar goes in? Are the back 2 implants (all-on-4) supposed to be angled?

While final restorations do provide better stability, screws for temporary restorations should not get loose.  It is important to understand WHAT is getting loose, as many parts can look the same.  It is common that patients refer to the implants themselves as screws, but some parts get called screws too.  Cover screws, healing abutments, and screws used to attach restorations are often called "screws" for simplicity, but some getting loose are more concerning than others.If you are still wearing removable dentures while implants heal, it may be cover screws or healing collars that are loose or falling out.  If that is the case, I would simply let everything heal and THEN address it.  If you have a temporary that is screwed in place (you can't take it out at home) and the screws keeping THOSE in place are loose, there may be a more complicated issue.The angle of implants is not critical.  The angles are common because of the patient anatomy, an attempt to spread out the implant interface over a greater distance without a need for a graft procedure.  If your dentist was able to get implants far enough apart without grafting or needing to angle the implants, this likely means you had favorable anatomy and no NEED to angle.

There are many reasons a screw losses1. Bite is off2. You could be grinding your teeth3. Not sufficient torque applied to the screw4. The prosthesis not fittingIt is not normal for the screws to loosen so frequently i would go back to your dentists and discuss thisThe back two implants are supposed to be angled to maximize the spread of the implantsWish you sucess

There are many reasons for why your screws can get loose such as; misfit and not enough torque to them when  they were placed.The back implants should be tilted to engage the best quality bone avoiding vital structures.The Titanium Bar serves as a substructure to strengthen your final teeth.