Surface temperature rise from dental cutting with air-turbine handpieces

Objective: the purpose of this study was to measure in vitro the temperature rise produced by dental cutting with air-turbine handpieces. Methods: six air-turbine handpieces with different coolant specification were used: Midwest XGT (XGT), BienAir (BA), Star (ST), Kavo 635B (K1), Kavo 649B (K2) and Siemens (SI); with 2 cutting instruments, diamond (D) and carbide (C); and under 3 parameters of air/water coolant, minimum (MN), medium (MU) and maximum (MX), varying the water flow rate (5-20 psi), water pressure (5-10 psi), chip air pressure (5-15 psi) and drive air pressure (30 psi). The teeth, extracted human molars, were positioned on a standardized cutting station and axial cuts (n=144) were performed for 15 s, 4 repetitions each, with independent variables of handpieces (n=24 cuts for each), burs (n=72 cuts for each), under 3 specific air/water flow settings (n=24 cuts for each). An infra-red camera was used to record the dependent variable of temperature rise on the tooth surface produced by the dental cutting, with a speed of 1 scan every 45 ms. A two-factor ANOVA was used for statistical analysis (p<0.05). Results: