Thurmond, those "teeth" actually stick up away from the grass, and are to provide upwards airflow / "suction". (Supposedly, they also blow air / clippings back towards the center of the blade, for subsequent repeat cutting / mulching and a more even clipping distribution.)

I should have looked at the full sized picture. I see it is a mulching blade now. No lawnmower blade I have ever had would drill easily. Use lots of cutting fluid and very good bits and you may get it done.

Thurmond