Dental USA 1412 Scalers/Curettes Cattoni 107/108 Dental USA perfects the unique angles and sharpens each blade. Dental USA raises the level of heat treating to a 50-55 hardness rating Proper bending of each tip, from 1 to 6 times, to insure proper use qualities. Purchasing the best quality materials. Skilled technicians are manufacturing the shapes of each tip.