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.