J Korean Acad Conserv Dent.  2004 Jul;29(4):386-398. 10.5395/JKACD.2004.29.4.386.

The polymerization rate and the degree of conversion of composite resins by different light sources

• Ryoo JH
• Lee IB
• Yoo HM
• Kim MJ
• Seok CI
• Kwon HC

• KMID: 2175633
• DOI: http://doi.org/10.5395/JKACD.2004.29.4.386

Abstract

OBJECTIVES
The purpose of this study was to observe the reaction kinetics and the degree of polymerization of composite resins when cured by different light sources and to evaluate the effectiveness of the blue Light Emitting Diode Light Curing Units (LED LCUs) compared with conventional halogen LCUs.
MATERIALS AND METHODS
First, thermal analysis was performed by a differential scanning calorimeter (DSC). The LED LCU (Elipar Freelight, 320 mW/cm2) and the conventional halogen LCU (XL3000, 400 mW/cm2) were used in this study for curing three composite resins (SureFil, Z-250 and AEliteFLO). Second, the degree of conversion was obtained in the composite resins cured according to the above curing mode with a FTIR. Third, the measurements of depth of cure were carried out in accordance with ISO 4049 standards. Statistical analysis was performed by two-way ANOVA test at 95% levels of confidence and Duncan's procedure for multiple comparisons.
RESULTS
The heat of cure was not statistically different among the LCUs (p > 0.05). The composites cured by the LED (Exp) LCUs were statistically more slowly polymerized than by the halogen LCU and the LED (Std) LCU (p < 0.05). The composite resin groups cured by the LED (Exp) LCUs had significantly greater degree of conversion value than by the halogen LCU and the LED (Std) LCU (p = 0.0002). The composite resin groups cured by the LED (Std) LCUs showed significantly greater depth of cure value than by the halogen LCU and the LED (Exp) LCU (p < 0.05).

Keyword

LED light curing units; DSC; Heat of cure; Maximum rate of heat output; Peak heat flow time; Degree of conversion; Depth of cure

MeSH Terms

Composite Resins*
Hot Temperature
Kinetics
Polymerization*
Polymers*
Spectroscopy, Fourier Transform Infrared
Composite Resins
Polymers

Figure

• 

  Figure 1 DSC cell section and acrylic stand to fix light guide.

• 

  Figure 2 Stainless steel mold cross-section.

• 

  Figure 3 Heat of cure (-△H : J/g) of each resin with different light sources.

• 

  Figure 4 Maximum rate of heat output (watt/g).

• 

  Figure 5 Mean time to reach peak heat output (sec).

• 

  Figure 6 Degree of conversion (%) of each resin with different light sources.

• 

  Figure 7 Depth of cure (mm) of each resin with different light sources.

• 

  Graph 1 DSC thermogram of Z-250 when cured with Elipar Freelight (Std)-LED

• 

  Graph 2 FTIR spectrum of SureFil when cured with Elipar Freelight (Std)-LED

Reference

1. Ruyter IE, Oysaed H. Conversion in different depths of ultraviolet and visible light activated composite materials. Acta Odontol Scand. 1982. 40:179–192.

2. Althoff O, Hartung M. Advances in light curing. Am J Dent. 2000. 13(Spec No):77D–81D.

3. Council on Dental Materials, Instruments, and Equipment. Visible light-cured and activating units. J Am Dent Assoc. 1985. 110:100–123.

4. Rueggeberg FA, Twiggs SW, Caughman WF, Khajotia S. Lifetime intensity profiles of 11 light-curing units. J Dent Res. 1996. 75:380.

5. Barghi N, Berry T, Hatton C. Evaluating intensity output of curing lights in private dental offices. J Am Dent Assoc. 1994. 125:992–996.

6. Martin FE. A survey of the efficiency of visible light curing units. J Dent. 1998. 26(3):239–243.

7. Miyazaki M, Hattori T, Ichiishi Y, Kondo M, Onose H, Moore BK. Evaluation of curing units used in private dental offices. Oper Dent. 1998. 23:50–54.

8. Lee SY, Chiu CH, Greener EH. Radiometric and spectroradiometric comparison of power outputs of five visible light-curing units. J Dent. 1993. 21(6):373–377.

9. Nomoto R. Effect of light wavelength on polymerization of light cured resins. Dent Mater J. 1997. 16(1):60–73.

10. Mills RW, Jandt KD, Ashworth SH. Dental composite depth of cure with halogen lamp and blue light emitting diode technology. Br Dent J. 1999. 186:388–391.

11. Jandt KD, Mills RW, Blackwell GB, Ashworth SH. Depth of cure and compressive strength of dental composites cured with blue light emitting diodes (LEDs). Dent Mater. 2000. 16:41–47.

12. Stahl F, Ashworth SH, Jandt KD, Mills RW. Light emitting diode(LED) polymerization of dental composites. Biomaterials. 2000. 21:1379–1385.

13. Fujibayashi K, Ishimaru K, Kohno A. A Study on light activation units using blue light-emitting diode. J Jpn Dent Pres Acad. 1999. 38:180–188.

14. Fujibayashi K, Ishimaru K, Takahashi N, Kohno A. Newly developed curing unit using blue light-emitting diode. Dent Jpn (Tokyo). 1998. 34:49–53.

15. Asmussen E, Peutzfeldt A. Light-emitting diode curing : Influence on selected properties of resin composites. Quintessence Int. 2003. 34(1):71–75.

16. Nomura Y, Teshima W, Tanaka N, Yoshida Y, Nahara Y, Okazaki M. Thermal analysis of dental resins cured with blue light-emitting diodes (LEDs). J Biomed Mater Res. 2002. 63(2):209–213.

17. Kurachi C, Tuboy AM, Magalhaes DV, Bagnato VS. Hardness evaluation of a dental composite polymerized with experimental LED-based devices. Dent Mater. 2001. 17(4):309–315.

18. Dunn WJ, Bush AC. A comparison of polymerization blue light-emitting diode and halogen-based light-curing units. JADA. 2002. 133(3):335–341.

19. Kanca J 3rd, Suh BI. Pulse activation : Reducing resin based composite contraction stresses at the enamel cavosurface margin. Am J Dent. 1999. 12(3):107–112.

20. Uno S, Asmussen E. Marginal adaptation of a restorative resin polymerized at reduced rate. Scand J Dent Res. 1991. 99(5):440–444.

21. Yap AU, Soh MS, Siow KS. Effectiveness of composite cure with pulse action and soft-start polymerization. Oper Dent. 2002. 27(1):44–49.

22. Wolcott RB, Paffenbarger GC, Schoonover IC. Direct resinous filling meterials : Temperature rise during polymerization. JADA. 1951. 42:253–263.

23. McCabe JF, Wilson HJ. The use of DSC fo the evaluation of dental materials. J Oral Rehabil. 1980. 7:103–110.

24. Abadie MJM, Appelt BK. Photocalorimetry of light cured dental composites. Dent Mater. 1989. 5:6–9.

25. Vaidyanathan J, Vaidyanathan TK, Wang Y, Viswanadhan T. Thermoanalytical characterization of visible light cure dental composites. J Oral Rehabil. 1992. 19:49–64.

26. Lee IB, Um CM. Thermal analysis on the polymerization rate of dual cured resin cements under porcelain inlays. J Oral Rehabil. 2001. 28:186–197.

27. Lee H, Colby C. Heat of polymerization of nine mono-, di-, and trimethacrylate esters tested neat and with low levels of peroxide by dynamic differential scanning colorimetry. Dent Mater. 1986. 2:175–178.

28. Chung K, Greener EH. Degree of conversion of seven visible light-cured posterior composites. J Oral Rehabil. 1988. 15:555–560.

29. Ferracane JL, Greener EH. Infrared analysis of degree of polymerization in unfilled resins methods comparison. J Dent Res. 1984. 63:1093–1095.

30. International Standard ISO 4049. Dentistry-polymer-based filling, restorative and luting materials. 2000. Geneva, Switzweland: International Standards Organizations 14-15.

31. Fan PL, Standford CM, Stanford WB, Leung R, Standford JW. Effects of backing reflectance and mold size on polymerization of photo-activated composite resin. J Dent Res. 1984. 63(10):1245–1247.

32. Manga RK, Charlton DG, Wakefied CW. In vitro evaluation of curing radiometer as a predictor of polymerization depth. Gen Dent. 1995. 241–243.

33. Rueggeberg FA, Cratg RG. Correlation of parameters used to estimate monomer in a light cured composite. J Dent Res. 1988. 67:932–937.

34. Sakaguchi RL, Douglas WH, Peters MC. Reduced light intensity decreases post-gel contraction while maintaining degree of conversion in composites. J Dent. 1998. 26:434–445.

35. Davidson CL, Feilzer AJ. Polymerization shrinkage and polymerization shrinkage stress in polymer-based restoratives. J Dent. 1997. 25(6):435–440.

36. Venhoven BAM. Light initiation of dental resins ; dynamics of the polymerization. Biomaterials. 1996. 17:2313–2318.

37. Odian G. Principles of polymerization. 1991. 3rd edition. John Wiley & Sons, Inc.;198–243. 286–290.

38. St-Georges AJ, Swift EJ, Thomson JY, Heymann . Curing light intensity effects on wear resistance of two resin composite. Oper Dent. 2002. 27:410–417.

39. Knezević A, Tarle Z, Meniga A, Sutalo J, Pichler G, Ristic M. Photopolymerization of composite resins with plasma light. J Oral Rehabil. 2002. 29:782–786.

40. Kelsey WP, Blankenau RJ, Powell GL, Barkmeier WW, Stromberg EF. Power and time requirements for use of the argon laser to polymerize composite resin. J Clin Laser Med Surg. 1992. 10:273–278.

41. Koliniotou-Kubia E, Jacobson PH. The effect of irradiation time on the physical properties of light-cured resins. Clin Mater. 1990. 6:21–28.

42. Stansbury JW, Dickens SH. Determination of double bond conversion in dental resins by near infrared spectroscopy. Dent Mater. 2001. 17:71–79.

43. Burgess JO, DeGoes M, Walker R. An evaluation of four light-curing units comparing soft and hard curing. Pract Periodontics Aesthet Dent. 1999. 11:125–132.

44. Mills RW, Uhl A, Blackwell GB, Jandt KD. High power light emitting diode arrays versus halogen light polymerization of oral biomaterials : Barcol hardness, compressive strength and radiometric properties. Biomaterials. 2002. 23:2955–2963.

45. Rueggeberg FA, Caughman WF, Curtis JW. Effect of light intensity and exposure duration on cure of resin composites. Oper Dent. 1994. 19:26–32.

46. Fowler CS, Swartz ML, Moore BK. Efficacy testing of visible light curing units. Oper Dent. 1994. 19:47–52.

47. DeWald JP, Ferracane JL. A comparison of four modes of evaluating depth of cure of light activated composite. J Dent Res. 1987. 66(3):727–730.

48. Ruyter IE, Oysaed H. Conversion in different depths of ultraviolet and visible light activated composite materials. Acta Odontol Scand. 1982. 40:179–192.

49. Soh MS, Yap AUJ, Siow KS. Effectiveness of composite cure associated with different curing modes of LED lights. Oper Dent. 2003. 28(4):371–377.

50. Park SH, et al. The amounts and speed of polymerization shrinkage and microhardness in LED cured composites. J Korean Acad Conserv Dent. 2003. 28(4):354–359.