Handpiece coolant flow rates and dental cutting

High-speed handpieces incorporate water coolant sprays to remove cutting de bris and minimize thermal insult to the pulp. Little data exists on optimal coolant flow rates during clinical procedures. This study compared the eff ect of different coolant flow rates on diamond stone cutting efficiency. Cutting studies were performed on Macer machinable ceramic using a previous ly developed test regimen-a KaVo high-speed handpiece at a cutting force of 91.5 g (0.9N). Cutting was performed with round end tapered medium grit di amond stones under cooling water now rates of 15, 20, 25, 30 and 44 ml/min, with cutting rates determined as the time to transect the 13 mm square cro ss-section of the Macer bar. Each bur was used for five cuts, with six burs used for each flow rate, for a total of 150 measurements. The data were an alyzed by one-way ANOVA with a post hoc Scheffe test. The cutting studies indicated that diamond stone cutting rates increased wi th higher coolant flow rates over the range of 15-44 ml/min. The data sugge st that higher coolant flow rates promote cutting efficiency.