G.B.
In child care we can often tell which kids are going to be biters because of this particular kind of activity. I am giving you some links but not implying your child is a biter, just the chew part of it. Some kids need to have more chew time and they are constantly doing this kind of stuff. That is why they tend to bite, it feels good to them and they just need to chew on something...lol.
On the other hand, she should visit a pediatric dentist to see if she has cavity's she may also have something stuck in her gums, like a tiny popcorn hull. It is often something wrong with the teeth that causes a child to chew on items.
Kids that do this kind of activity will often grow up to bite their nails too. So finding out what the reason is may help stop lots of annoying habits that could plague her the rest of her life.
Here are some good links to articles that cover a variety of topics but all having something to do with giving more chew time and appropriate things to chew.
**********************************************************
I like the idea of a picture book she can help you make of things you feel comfortable with her chewing on.
http://www.examiner.com/child-care-in-oklahoma-city/child...
********************************************************
This one talks about exploration of her world, she's learning by putting stuff in her mouth. She also may need some chewy foods to make her jaw tired then she won't want to chew for a while.
http://extension.unh.edu/family/documents/hcdvs105.pdf
**********************************************************
Never heard of a chew tube before but it works like this, they put the tube in their mouth and are allowed to chew on it when they want to chew something. It allows kids with SPD to focus more and not be distracted. I remember one time I was playing BINGO with some friends and we had done several speed rounds. I was way too slow. I had just picked up a rice cake to snack on and had it in my teeth to bite it when the next speed round started. I was faster than all my friends who played every night. It was amazing to me so I know there is something to the mouth staying busy things....LOL.
http://www.sensory-processing-disorder.com/chewy-tubes.html