The Journal of Contemporary Dental Practice

Register      Login



Volume / Issue

Online First

Related articles

VOLUME 8 , ISSUE 2 ( February, 2007 ) > List of Articles


Radiometric and Spectrophotometric Analysis of Third Generation Light-Emitting Diode (LED) Light-Curing Units

Barry M. Owens, Kelbin H. Rodriguez

Citation Information : Owens BM, Rodriguez KH. Radiometric and Spectrophotometric Analysis of Third Generation Light-Emitting Diode (LED) Light-Curing Units. J Contemp Dent Pract 2007; 8 (2):43-51.

DOI: 10.5005/jcdp-8-2-43

License: CC BY-NC 3.0

Published Online: 01-02-2007

Copyright Statement:  Copyright © 2007; Jaypee Brothers Medical Publishers (P) Ltd.



Light-emitting diode (LED) polymerization of dental restorative materials has become increasingly popular. However, individual light-curing unit (LCU) functions (intensity and/or wavelength emission) may not conform to manufacturer specifications due to quality control issues. The purpose of this study was to evaluate the quality of irradiance, in terms of power density (intensity) and spectral distribution (peak wavelength), emitted from LED and quartz-tungsten halogen (QTH) LCUs in vitro. The battery expenditure of these LED units was also tested.

Methods and Materials

The intensity and spectral distribution from four third generation LED (Smartlite PS, Coltolux LED, radii Plus, Diopower) and one QTH (Schein Visible Cure) light sources were measured using six different dental curing light meters (Coltolux, Cure Right, Demetron 100, Demetron LED., Hilux, and Light Meter-200) and a visible-ultraviolet light spectrophotometer (Hitachi Elmer-Perkins). The battery life was also plotted for each light source following a 1500 second duration period. The data obtained from radiometric and spectrophotometric analysis was compared to manufacturer specifications.


Radiometric evaluation revealed LED light units tested did not satisfy manufacturer claims for minimum intensities. Spectral emissions from the LED light sources did meet manufacturer requirements. No clinically appreciable battery drain was evidenced from testing all re-chargeable LED units.


Despite limitations LED technology appears to be an effective alternative for curing of lightactivated esthetic restorative materials. Additional advantages associated with LED curing lights include ergonomic handling capabilities, negative heat generation, and minimal maintenance concerns.


Owens BM, Rodriguez KH. Radiometric and Spectrophotometric Analysis of Third Generation Light- Emitting Diode (LED) Light-Curing Units. J Contemp Dent Pract 2007 February;(8)2:043-051.

PDF Share
  1. Effect of irradiation type (LED or QTH) on photo-activated composite shrinkage strain kinetics, temperature rise, and hardness. Eur J Oral Sci 2002;110:471-479.
  2. Composite cure and pulp-cell cytotoxicity associated with LED curing lights. Oper Dent 2004 Jan-Feb; 29: 92-99.
  3. Evaluation of a dual peak third generation LED curing light. Compendium 2005 May; 26:331-347.
  4. Composite conversion and temperature rise using a conventional, plasma arc, and an experimental blue LED curing unit. J Oral Rehab 2002;29:662-667.
  5. Curing performance of a new-generation light-emitting diode dental curing unit. J Am Dent Assoc 2004 October; 135:1471-1479.
  6. Light-emitting diode curing: Influence on selected properties of resin composites. Quintessence Int 2002;34:71-75.
  7. Comparison of linear shrinkage and microhardness between QTH-cured & LED-cured composites. Oper Dent 2005 July-Aug; 30:461-467.
  8. Dental composite depth of cure with halogen and blue light emitting diode technology. Br Dent J 1999 Aug; 186: 388-391.
  9. Light-curing technology: Past, present, and future. Compendium 2002 Sept; 23:18-24.
  10. High power light emitting diode (LED) arrays versus halogen light polymerization of oral biomaterials: Barcol hardness, compressive strength and radiometric properties. Biomat 2002;23:2955-2963.
  11. Depth of cure and compressive strength of dental composites cured with blue light emitting diodes (LEDs). Dent Mat 2000 Jan; 16:41-47.
  12. Radiometric and spectroradiometric comparison of power outputs of five visible light-curing units. J Dent 1993;21:373-377.
  13. Spectral distribution of dental photopolymerization sources. J Dent Res 1982 Dec; 61:1436-1438.
  14. Polymerization efficiency of curing lamps: A universal energy conversion relationship predictive of conversion of resin-based composite. Oper Dent 2004 Jan-Feb; 29:105-111.
  15. Effect of light wavelength on polymerization of light-cured resins. Dent Mater J 1997 Jan; 16:60-73.
  16. The application of photochemistry to dental materials. In:Gebelein CG, Koblitz FK. Biomedical and dental applications of polymers. New York: Plenum Press, 1981;411-416.
  17. A visible light-cured composite restorative. Clinical open assessment. Br Dent J 1978 Nov; 145:327-330.
  18. Visible light-cured composites and activating units. J Amer Dent Assoc 1985 Jan;110:100-103.
  19. A comparison of polymerization by light-emitting diode and halogen-based lightcuring units. J Amer Dent Assoc 2002 Mar; 133:335-341.
  20. 3M-ESPE 2002:1-6.
  21. A survey of the efficiency of visible light curing units. J Dent 1998;26:239-243.
  22. Polymerization and light-induced heat of dental composites cured with LED and halogen technology. Biomat 2003;24:1809-1820.
  23. JW. Factors affecting cure at depths within light-activated resin composites. Am J Dent 1993;6:91-95.
  24. Effect of air, dentin and resin-based composite thickness on light intensity reduction. Am J Dent 1999;12:231-234.
  25. Factors affecting cure of visible light activated composites. Int Dent J 1985;35:91-95.
  26. Some factors influence+ng the depth of cure of visible light-activated composite resins. Aust Dent J 1990 Mar; 35:213-218.
  27. Effect of light intensity and exposure duration on cure of resin composite. Oper Dent 1994;19:26-32.
  28. Status report on microfilled composite restorative resins. J Amer Dent assoc 1982 Mar; 105:488-492.
  29. Effect of light source and specimen thickness on the surface hardness of resin composite. Am J Dent 2002;15:47-53.
  30. The relationship between cure depth and transmission coefficient of visible-light-activated resin composites. J Dent Res 1994 Feb; 73:516-521.
  31. Depth of cure of radiation-activated composite restoratives – Influence of shade and opacity. J Oral Rehabil 1995;22:337-342.
  32. Precision of hand-held radiometers. Oper Dent 1993 Nov-Dec; 24:391-396.
  33. Light curing unit effectiveness assessed by dental radiometers. J Dent 1995;23:227-232.
  34. The art and science of operative dentistry. 3rd ed. St. Louis: Mosby; 1995:260.
  35. Effect of curing-tip diameter on the accuracy of dental radiometers. Oper Dent 1999;24:31-37.
  36. Reliability of three dental radiometers. Scand J Dent Res 1993;101:115-119.
  37. Light meters – reality original report. Reality Now 1991;21:1-3.
  38. Correlation between recordings obtained with a light-intensity tester and degree of conversion of a light-curing resin. Scand J Dent Res 1994;102:73-75.
  39. A survey of the effectiveness of dental light-curing units and a comparison of light testing devices. Br Dent J 1996;180:411-416.
  40. Degree of polymerization of resin composites by different light sources. J Oral Rehab 2002; 29:1165-1173.
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.