Originally posted elsewhere by 4skwerlz --

Here is a link to a National Science Foundation digital library tool showing an Eastern Fox squirrel skull. It's neat because you can rotate it, etc., to see the teeth from all angles:

http://www.digimorph.org/specimens/Sciurus_niger/

Here is another picture, which shows proper alignment of the teeth in the Eastern Grey Squirrel. The enamel is harder on the front of the tooth than on the back, causing these teeth to be worn to a sharp edge, like a chisel. This creates a very sharp bite. The photo below shows this clearly. This implies that if you can trim the teeth to the proper length, then assuming the teeth "meet" correctly, natural wear would create the "angles."

http://www.univagro-iasi.ro/simpozio...clinici/14.pdf