This page takes you step-by-step through the correct method for sharpening your hand instruments. The principals used in sharpening tips can be applied to any similar scaler or curette. Pictures are shown to demonstrate the approximate angles you need to hold the instrument at. Please note that in most pictures, the stone is not steadied by another hand, and no mineral oil is used on the stone for image clarity.
This short guide will use examples of most instrument shapes you will come across, decribing how to sharpen the following tips:
Jacquette 1
H6
McFarlane 1
Columbia 13
Gracey 9
Excavator 126
Introduction
DENTSPLY Ash Instruments are delivered to you with factory-sharp cutting edges. These will remove calculus with minimum effort and will cause the least possible trauma to the tooth, root or gingival surface.
Gradually, this precisely angled cutting edge will be dulled by contact with hard tooth enamel, making calculus removal harder. This will mean the procedure takes longer, and could result in burnishing calculus. The instrument could also damage the gingiva by skidding along the surface instead of cutting.
Keeping your Ash periodontal instruments sharp is simple and takes little time. By following a simple sharpening routine, your instruments will reward you with a long trouble-free working life.
Introducing the Sharpening Equipment
The Ash Sharpening Kit comes supplied with the following equipment (Order ref: 62499200):
2 x Test Stick – This acrylic rod is easy to use for testing instrument sharpness (angle the handle 45° to the stone). Always test all parts of the cutting edge with the Test Stick - this is much safer and more hygienic than using something like your thumb nail, which may harbour bacteria.
Sharpening Oil – A light mineral oil, used to lubricate the sharpening stone and carry away metal debris.
Flat Sharpening Stone – The Ash Sharpening kit contains a smooth, man-made stone that will create as fine an edge as an Arkansas stone, yet is long-lasting and hard enough to re-shape blunt instruments.
Sharpening Rod – A 3.5mm stone rod, used to give a final edge to curved blades
You may also find that a magnifying glass or, ideally, a x10 Loupe will help you see the instrument cutting edge and angles you have created.
Cleaning and Sterilisation
Always clean instruments before sharpening. Sterilisation instructions for all Ash hand instruments can be found here. Your sharpening kit can be kept clean with soap and water.
Getting Started
The objective of sharpening is to maintain the original blade contour created by the original factory technician. With a little practice, any shape of cutting edge can be sharpened successfully. Remember you don't need to sharpen tungsten carbide (TC)-tipped instruments (most Ash Instrument Hoes have TC tips).
To begin sharpening, you need to understand the instrument shape and where the correct cutting edges are. You may find it useful to examine an unused instrument at this stage.
To assess the instrument, view the cutting edge in good light. This edge will appear as a bar of light when blunt, but appear to have no width when sharp. Magnification will help you identify this more easily as you are learning. Two basic grips are used when sharpening: the Pen Grip; and the Palm Grip.
Pen Grip
Hold your forefinger on the neck of the instrument with your thumb behind, and handle resting between the first joint of the middle finger
Palm Grip
Take the instrument between your forefinger and thumb, with the rest of the instrument disappearing in the palm of your hand
To begin sharpening, place the stone about 15cm (6 inches) in front of you and hold it with one hand to steady it. Sharpen with a flat stone on a level surface, to reduce the risk of cutting your hand should the instrument, or stone slip, and make no more than three strokes at any one time; check and repeat if more sharpening is necessary. Note that sharpening instruments eventually alters the shape and reduces the size of the blade. The instrument will also weaken after repeated sharpening, and may collapse during clinical use. DENTSPLY recommends you replace all cutting instruments when the blade has been reduced by 50%.
Jaquette 1 Sickle Scaler
All sickle scalers have blades that have a trapezoid cross section, with two cutting edges, either side of the top face. Sharpening is performed on both lateral faces; the top face should not need to be touched.
1. Taking the instrument in the Pen Grip, place one of the lateral faces at about 30° to the stone.
2. Move the face forward and backward against the stone, putting pressure on it in a pull direction.
3. Turn the instrument over and perform the same action with the other lateral face.
4. Test the tip for sharpness (if there is evidence of a rough 'wire' edge, remove this using the stone rod in a rolling motion).
Make the final stroke in the pull direction (into the cutting edge) to remove any wire edge.
H6 Sickle Scaler
This tip has the same, nearly triangular, blade cross-section as the Jacquette 1, but it has a much longer cutting edge and the blade is offset. As before, sharpening is only performed on the lateral faces, the top edge should not need to be touched.
1. Taking the instrument in the Pen Grip, and place the blade flat to the stone.
2. Angle the handle to 45° to the stone.
3. Push the instrument forward and back over the stone, but apply pressure when pushing the instrument away.
4. Test the tip for sharpness and remove any wire edge.
McFarlane 1 Push Scaler
As push scalers are used in the opposite direction to all other scalers, they are also sharpened differently. Take care when positioning the hand holding the stone so that you will not injure yourself should the scaler slip while you are pushing.
1. Taking the instrument in the Pen Grip, and place the blade flat to the stone.
2. Angle the handle to 45° to the stone.
3. Push the instrument forward and back over the stone, but apply pressure when pushing the instrument away.
4. Test the tip for sharpness and remove any wire edge.
Columbia 13 Universal Curette
Universal curettes have blades at 90° to the shank. The toe is rounded and the lateral faces are cut back so that both have cutting edges.
1. Taking the instrument in a Pen Grip, turn the blade so that the hook faces left. If viewed from the side, the curved portion towards the toe will face downwards.
2. Angle the blade to about 30° from the stone.
3. Move the blade forwards and backwards over the stone, putting pressure on in the “pull” direction, and moving around the curve of the blade.
4. Turn the blade over and change to the Palm Grip.
5. Move the stone to the edge of the table or bench you are working on and lower the handle angle to 10° to the stone.
6. Again, move the blade forwards and backwards, adding pressure when pulling.
7. Test the tip for sharpness and remove any wire edge.
8. Finally, ensure that the toe has not become pointed: if necessary rework around the toe to regain its shape.
Gracey 9 Dedicated Curette
Dedicated curettes have blades that are 70° to the shank; the toe is rounded; and only one lateral face is cut back, so they only have one cutting edge. Raise the edge of the sharpening stone (for example, with a test stick) to better see the 70° cutting edge.
1. Taking the instrument in a Pen Grip, turn the blade so that the hook faces left. If viewed from the side, the curved portion towards the toe will face downwards.
2. Angle the blade to about 30° from the stone.
3. Move the blade forwards and backwards over the stone, putting pressure on in the “pull” direction, and moving around the curve of the blade.
4. Test the tip for sharpness and remove any wire edge.
5. Finally, ensure that the toe has not become pointed, and rework as necessary.
Excavator 126
1. Hold the instrument in either the Pen or Palm grip, whichever is more comfortable.
2. Hold the instrument at around 30°, place the one side of the tip's cutting edge onto the stone push the tip forward and backwards, rocking your way around the edge as you go.
3. Continue this process all the way around the tip, adjusting the instrument angle as necessary to following the tip shape.
4. Test the tip for sharpness, removing wire edges as necessary. Caution Take care not to create points or corners while sharpening; the cutting edge should form a continuous curve.