Objective: the purpose of this investigation was to measure, in vitro, the maximum temperature at the Nd:YAG laser fiber optic tip, with and without air/water coolant. Methods: a pulsed free running Nd:YAG laser, emission wavelength 1064nm, pulse duration 110 m s, was used varying parameters of power (W) and repetition rate (Hz) and energy per pulse (mJ/pulse) for 30s, with a 300m m diameter fiber, under 4 settings of air/water coolant at 15 psi: none (NN); minimum (MN) (4ml/min); medium (MU) (8ml/min); and maximum (MX) (12ml/min). The maximum temperature at the fiber tip was measured, 4 repetitions each (n=144), using an infra-red camera, with a speed of 1 scan every 45 ms. A two-factor ANOVA was used for statistical analysis (p≤0.05). Results: the effect of laser parameters on surface temperature is shown in the following table:

Means table for Maximum Temperature (^OC) ±1SD

W	Hz	mJ/pulse	NN	MN	MU	MX
0.5	10	50	24.0± (0.7)	20.4± (1.3)	20.4± (1.5)	21.8± (0.1)
1.0	10	100	32.8± (0.9)	18.2± (1.5)	17.6± (0.1)	17.0± (0.1)
1.5	10	150	45.1± (3.0)	18.3± (0.7)	24± (0.7)	24± (0.7)
2	20	100	46.6± (1.0)	18.4± (0.3)	18.4± (0.3)	18.9± (0.2)
2.5	20	125	48.6± (1.3)	18.9± (0.5)	19.2± (0.6)	18.7± (0.1)
3.0	20	150	54.4± (0.9)	21.3± (2.6)	20.7± (0.9)	20.5± (0.3)
2.0	50	40	39.5± (0.6)	16.7± (0.1)	17.1± (0.1)	17.7± (0.2)
2.5	50	50	34.4± (0.3)	19.9± (0.1)	20.0± (0.1)	20.4± (0.4)
3	50	60	38.9± (3.1)	20.0± (0.1)	20.1± (0.2)	20.4± (0.1)

The effect of coolant on surface temperature was NN>MN=MU=MX.

Conclusions: laser parameters affect the fiberoptic surface temperature, which is directly related to energy per pulse. The addition of an air/water coolant significantly lowered surface temperature on the fiberoptic tip for all laser parameters tested. Supported by Lares Research.

Back to the Prosthodontics Research Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

Top Level Search