Have you also tried it with SASHA's original shaders?

Since I don't have the "Real Skin for V4" utility, I can't say much about it except that it's not a problem caused by SASHA. As you said, all V4 figures have the same problem, so it must be caused by that particular script.

You might want to try this:

https://www115.zippyshare.com/v/wqKPB3Yn/file.html

Unfortunately Rendo doesn't allow attaching ZIP files, thus I had to upload my own shader for the teeth at zippyshare.

The ZIP contains the shader (as a material collection - .mc5) and the thumbnail. Copy it to anywhere you want in your library.

Maybe it helps to fix your problem.

K

.

NOTE:

Select your figure, go to the Material Room, then click the library thumbnail. The shader will only replace the shaders for the teeth and gums, leaving everything else intact.