Is it possible to use a prosthesis with the All on 4 that would not have fake gums? What are gumless prosthesis called?

Answer is: There is really no "technical" name for an All-on-4 with no pink, but it has been classified by several people. The first of which was Dr Carl Misch. He called classified a fixed implant bridge with no vertical bone loss as an "FP1"; the teeth are generally averaged height/width.  He classified a fixed implant bridge with minimum  vertical bone loss as an "FP2"; the tooth proportions start getting longer, but no "pink" is used. An "FP3" is a bridge that has pink, due to the vertical, and often horizontal bone loss.If you are considering "No pink" the Acrylic (Denture tooth) version is not generally an option. You would have to consider a Zirconia or Porcelain fused to metal bridge. (Typically, more complex to plan clinically and fabricate in the laboratory)As with all information, seek consultation in person with a dental professional,  prior to deciding on any treatment.

In short, yes. However, this type of prosthesis is no longer called an All-on-4. This is a full arch bridge on dental implants. This type of treatment is much more expensive.  
This is definitely still possible, however more implants are usually advised for this type of prosthesis. This is a much more difficult procedure to have done correctly. It is difficult to predict the exact shape of the gums after the implants are placed and some revisions might have to be done in the future. A
The beauty about the All-on-4 is that it has the gums built in to it so that they can be made to look natural no mater what your real gums look like underneath. 

Thank you for your question. Regarding the situation that you are describing, there are anatomical variables that need to be considered when trying to obtain the type of goal you are looking for. Unfortunately if you have sustained a big amount of bone loss because of gum disease or missing teeth, it becomes more difficult to give you this type of therapy. Although, with today's technology we can grow both bone and soft tissue and thus get closer to the ultimate treatment goal you're seeking. These goals will require additional surgical procedures to augment the bone and soft tissue. I would recommend that you review your ideas with a periodontist. Good luck!

 The answer to your question lies in determining the amount of vertical height that your jawbone has lost.If your jawbone has good height, then the laboratory can fabricate you're All on-4 prosthesis  without the gums.If, however, you have experience significant  in your drawer, then the length of the teeth on the prosthesis would look ridiculous unless fake gum tissue was used. I hope you found this information to be helpful,Dr. Champagne 

I think first you need to know that the All on 4, was never designed to replace the multiple single implants, which would give you the feel of natural teeth. The All on 4 is an option for those patients that either do not want dentures or the have dentures and are feed up with them. Now you can get multiple single implants placed to replace missing or unrestorable teeth that need to be extracted. And this will definitely be an option for you, but the All on 4 will probably not be a good option for you. If you are desiring to have that tooth like feel in your mouth. However, the all on 4 works really well and the results are amazing. You just need to know what you want and ensure that your doctor does as well, so he can deliver what you are desiring.