had that machine... i always sharpened the teeth. get a "Greenwheel" from sherril? i think... USE EYE PROTECTION AND A FACE MASK and sharpen them outside if you can. take some of the steel off over the carbide, so the steel isnt hitting, get the bottom edge of it very square, i usually took quite a bit off... but it doubled the use of the teeth without shipping and paying someone to sharpen them. tips- get them to have the same angle as the original ones to. dont take TOO much off, or they can break off. dont grind the same one too long, itll over heat it and change the temper.
and... your at your own risk if you take my advice... but i did the above for 3 years without any problems.