Effect of Distance on Irradiance Received from Ten Curing Lights

Objectives: The power, spectral output and the irradiance received from one halogen and nine-LED curing lights were recorded to determine which light delivered the greatest irradiance from 0-8mm.

Methods: The power output(mW) from a prototype polywave Bluephase, UltraLume 5, Aurora, Bluephase 16i, LEDemetron II, FreeLight2, SmartLite iQ2, FlashLite1401, Radii Plus, and Optilux501 curing lights was measured using a calibrated integrating sphere attached to a spectroradiometer and a calibrated thermopile. The irradiance values were calculated using the active internal diameter of the light guides and the power recording. A 3.9mm diameter cosine corrector attached to the spectroradiometer was used to measure the effect of distance on the irradiance received at 0, 4, and 8 mm. The experiment was repeated three times and nine recordings were made for each brand of light at each distance using each of the recording techniques.

Results: Analysis of variance showed there was no significant difference in the irradiance reported by the three recording techniques (p=0.31). The spectral output from the polywave Bluephase was different from the other LED curing lights. Although the UltraLume 5 delivered a similar secondary peak in the 404nm range, this output was significantly less than that from the polywave Bluephase light. The polywave Bluephase LED curing light produced the greatest power output compared to the other lights. At both 4 and 8mm from the light guide, the polywave Bluephase light delivered the greatest irradiance (Scheffe test p<0.05). This was most marked at 8mm where the irradiance from the polywave Bluephase (1050mW/cm²) was almost three times the irradiance from the Bluephase 16i (385mW/cm²) and 10 times the irradiance delivered by the Flashlite1401 (94mW/cm²).

Conclusion: The polywave Bluephase light is a high power third-generation LED curing light that delivered the highest irradiance up to 8mm from the end of the light guide.

Irradiance mW/cm2
Distance	Bluephase Pro	Bluephase 161	Aurora	LEDemetron II	UltraLume 5	SmarLite IQ2	FreeLight 2	Optilux 501	Radii Plus	FlashLite 1401
4mm	1549	1046	961	857	633	608	560	540	310	203
8mm	1050	385	806	365	315	304	246	201	110	94