I was a dental lab tech for a while and still have my hand piece. Just a small dremel tool. I still have all the burrs or bits for it. I found one we just called a Goldie burr, just a small burr with a taper. It's a perfect fit. I have also just notched the area out with an Exacto Knife or rounded the area as shown in the photos. The notch or rounding of the edges is pretty much the norm.