When I got my two rescue boys, they had been in very bad circumstances. Their cage was caked with poo, their wheel was caked with poo, their claws were very long, sharp and caked with poo. I did my best to clean everything up but it's hard to tend to nails completely. So after playing with them for awhile, I got nasty puffy spots all over my arms where they were holding on. You dont even realize that the nails are piercing your skin ever so lightly, but they do it enough to inject bacteria under the skin, much like a tattoo pen. If you keep their nails dull, keep their cage clean and diet healthy, this goes away.
I think the same holds true for biting. Their teeth and mouth hold bacteria. If I were you, I wouldnt let yourself get bit. There are behavior modification methods that exist and work. In the end, your suggies are happy knowing that you are their dominant, feeder and handler.
Seems to always be the case with just about anything on here, but I would like to know what their diet has been lately. It has been said that mealworms and other hard bugs can help to brush teeth a little bit which may lower the bacteria in the mouth.
I have found that mine love to chew on old hard stale french bread. That is somewhat of a teeth scrubber as well. You can also train them to chew on paper items such as egg cartons, boxes and other things. I switch items out very often to keep them interested in new things.
As an additive you could try to find a hard dry cat food brand, hopefully one with a positive ca:p ratio. See if they might accept a few hand-fed kernals a night to brush their teeth. I have also heard of people serving monkey biscuits and other similar dry staple, but I would only do so as an after dinner treat kind of thing.