Coarse or Fine Grit Instrument Sharpening – Which To Use?
Whenever I ask a group “who likes to sharpen instruments?” no one raises a hand. I doubt that surprises you. When I then ask “who likes to scale and root plane with sharp instruments?” all hands go up. I fully agree with both answers.
I have gone so far as to say sharpening can be enjoyable. I said that in a blog no so long ago and got a response (I suspect sarcastic) “yea right”. What I really meant to say was using a sharp curette is a joy. Because of that, I guess I can admit that sharpening brings me joy. However, I can only take so much “joy”, so I want to get the job done with as little effort as possible. That is why I prefer to use a sharpener that has more coarseness that the typical fine grit stone I was trained with.
Most will agree that a medium grit sharpener sharpens faster that a fine grit sharpener. You may say, “but a coarser sharpener leaves a rougher edge” and I would not dispute that. I would, however, question the significance of it. If you look at a sharpened instrument’s edge under high magnification, the edge looks somewhat like a rugged mountain range. It is very irregular with many spike-like metal projections called wire edges. The coarser the sharpener, the more dramatic the irregularities are. This is a fact.
Now my opinion. Here are two pictures, one with a freshly sharpened edge and one with a dull edge.
You can’t see the irregularities of the sharpened edge very well because there is not much magnification. However, it’s a long way from the sharp edge to the dull edge.
How many strokes will it take to remove the imperfections along the sharpened edge? I suspect very few. For discussion purposes let’s say that it will take you 100 strokes during a procedure for your scaler to go from sharp (picture 1) to dull (picture 2). I maintain that the effects of the irregularity of the freshly sharpened edge will be gone in the first ten or so strokes. In addition, a series of articles written several years ago concluded that wire edges may actually enhance the scaling process. Think of it. If you use a coarser sharpener you sharpen faster and you create an efficient calculus remover that becomes an efficient planing instrument almost automatically.
So, do yourself and your patients a favor by getting rid of your fine Arkansas stones. Get a little more “grit” in your practice and get a better result faster.