[Scaler sharpening. Effect of the cutting edge of scaler and the epoxy resin surface with several types of sharpening stones and strokes].

The purposes of this study were to determine the characteristics of a sharpened scaler and planed epoxy resin surface under different sharpening conditions. Each scaler was sharpened with the following kinds of sharpening stones and sharpening strokes by using an originally designed sharpening machine: Stones: 1) Fine India stone (ISF) 2) Arkansas stone (AS) 3) Carborundum stone (CS) 4) ISF followed by AS (ISF + AS) 5) CS followed by AS (CS + AS). Strokes: 1) up strokes (PUSH) 2) down strokes (PULL) 3) up and down strokes (RE) Epoxy resin surfaces were planed (10, 20 and 40 strokes) by sharpened scalers. Before and after these sharpening procedures for each scaler, the cutting edge of each scaler was photographed with a scanning electron microscope (SEM) to determine its roughness and the number of wire edges. The epoxy resin surface was examined with the SEM and the surface roughness was analyzed with a profilometer. The following results were obtained: 1) ISF with three types of sharpening strokes produced the roughest cutting edge. 2) ISF and CS with three types of sharpening strokes produced the largest number of wire edges. 3) PUSH with the five types of sharpening stones showed the roughest cutting edge and the largest number of wire edges. 4) ISF and CS produced more surface roughness, and AS made a smoother surface. Epoxy resin surfaces were planed effectively after 10 strokes. However, no significant differences were found in the surface roughness after 10 to 40 strokes.