The effects of two sharpening methods on the strength of a periodontal scaling instrument

Several different techniques exist for sharpening periodontal scalers each of which will yield a relatively sharp instrument; however, some techniques may decrease the strength of the instrument more rapidly than others. The purpose of this study was to evaluate the effect of two different sharpening techniques on the strength of a periodontal scaler. Sixty McCall No. 13-14 scalers (SCI-DENT) were divided into groups of ten. Each group was reduced in size from 0 to 50% of a standard original size in increments of 10% by reducing the face of the instrument using an RX Honing Machine. A second set of 60 scalers was treated in a similar fashion by reducing the lateral surfaces of the instrument. Original angles and blade clearances were maintained on all instruments. Strength was measured by applying a force at a positive rake angle of 15 degrees in an Instron Testing Machine with a head speed of 50 cm/min. There were no significant differences in strength from grinding on the face vs. the lateral surfaces of the scaler in contrast to the observations of other investigators. Moreover, a 10 to 20% reduction can be accomplished before a significant drop in strength is observed by sharpening either the side or face of the instrument.