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VOLUME 3 , ISSUE 2 ( April-June, 2012 ) > List of Articles

RESEARCH ARTICLE

Curing Depth of Light-activated Nanofiller containing Resin Composites

Werner J Finger, Masafumi Kanehira, Yasuyuki Araki, Takehiko Wada, Andreas Utterodt, Masashi Komatsu

Citation Information : Finger WJ, Kanehira M, Araki Y, Wada T, Utterodt A, Komatsu M. Curing Depth of Light-activated Nanofiller containing Resin Composites. World J Dent 2012; 3 (2):119-125.

DOI: 10.5005/jp-journals-10015-1141

Published Online: 00-06-2012

Copyright Statement:  Copyright © 2012; Jaypee Brothers Medical Publishers (P) Ltd.


Abstract

Objective

To compare the depth of cure of nanofiller containing with conventional resin composites.

Materials and methods

Five nanofilled and nanohybrid composites were investigated and compared with a microfilled and a microhybrid reference, using the ISO 4049 scraping test, Knoop hardness (KHN) and DC profiling. Specimens from all materials (shade A3) were activated with the same LED light source for 20s. KHN (0.25N/15s) of three specimens each, produced in split molds was measured after 24 hours dark storage on sections perpendicular to the irradiated surface at 250 µm distance along the center line and two parallel lines, 0.5 mm apart, to a depth of 3 mm. Mean KHNs of the three neighboring indentations at each level were calculated. Degree of conversion (DC) was determined on specimens as mentioned above using micro-Raman spectroscopy at 125 µm distance with three measurements at each depth level.

Results

The depth of cure of all materials was >2 mm when determined according to the ISO test. KHN and DC data followed second order polynomial regression lines (r2 > 0.70; p < 0.001). At 2 mm depth, the KHN of six resin composites was ≤80% of the top KHN whereas the DC of all materials was ≥86% of the maximum DC at the irradiated surface.

Conclusion

The ISO scraping test overemphasizes the attainable depth of cure, when compared with 80% of top KHN as arbitrarily defined curing depth. KHNs reflect the crosslink density of the polymer, whereas DC additionally includes double bond conversions not contributing to enhancement of mechanical characteristics.

How to cite this article

Kanehira M, Araki Y, Finger WJ, Wada T, Utterodt A, Komatsu M. Curing Depth of Light-activated Nanofiller containing Resin Composites. World J Dent 2012;3(2): 119-125.


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  1. Light transmission on dental resin composites. Dent Mater 2008;24:571-76.
  2. Influence of light intensity on two restorative systems. J Dent 1995;23:183-89.
  3. Correlation of cytotoxicity, filler loading and curing time of dental composites. Biomaterials 1991;12:737-40.
  4. Depth of cure of radiation activated composite restoratives. Influence of shade and opacity. J Oral Rehabil 1995;22:337-42.
  5. Relationship between shade and depth of cure for light-activated dental composite resins. Dent Mater 1986;2:80-84.
  6. The effect of curing light variations, bulk curing and wall-to-wall quality of two types and various shades of resin composites. Dent Mater 1997;13:344-52.
  7. Raman scattering determination of the depth of cure of light-activated composites: Influence of different clinically relevant parameters. J Oral Rehabil 2002;29:510-15.
  8. Light exposure required for optimum conversion of light activated resin systems. Dent Mater 2006;22:1135-42.
  9. Influence on curing tip distance on resin composite Knoop hardness number, using three different light curing units. Oper Dent 2003;28:315-20.
  10. Dentistry— polymer-based filling, restorative and luting materials. ISO 4049:2010(E).
  11. Depth of cure of dental resin composites: ISO 4049 depth and microhardness of types of materials and shades. Oper Dent 2008;33:408-12.
  12. A comparison of four modes of evaluating depth of cure of light-activated composites. J Dent Res 1987;66:727-30.
  13. Quality of curing in relation to hardness, degree of cure and polymerization depth measured on nano-hybrid composite. Am J Dent 2007;20:263-68.
  14. Composite depth of cure obtained with QTH and LED units assessed by microhardness and micro-Raman spectroscopy. Oper Dent 2007;31:79-83.
  15. Evaluation of curing light distance on resin composite microhardness and polymerization. Oper Dent 2007;32:571-78.
  16. Post-irradiation polymerization of different anterior and posterior visible light-activated resin composites. Dent Mater 1992;8:299-304.
  17. Factors affecting cure at depths within light-activated resin composites. Am J Dent 1993;6:91-95.
  18. Composite depth of cure using four polymerization techniques. J Appl Oral Sci 2009;17:446-50.
  19. Determination of the degree of cure of dental resins using Raman and FT-Raman spectroscopy. Dent Mater 1993;9:317-24.
  20. The micro-Raman spectroscopy, a useful tool to determine the degree of conversion of light-activated composite resin. J Biomed Mater Res 1999;48:675-81.
  21. Gaussian 09. Revision B.1. Gaussian, Inc., Wallingford CT, 2009.
  22. Curing-light intensity and depth of cure of resin-based composites tested according to international standards. J Amer Dent Assoc 2002;133:429-34.
  23. Comparison of depth of polymerization evaluation methods for photo-activated composite. J Dent Res 1984;63:262 (Abstract No. 1095).
  24. Degree of double bond conversion in light-cured composites. Dent Mater 1987;3:19-25.
  25. Effect of exposure time vs irradiance on Knoop hardness of dental composites. Mater Res 2006;2: 275-80.
  26. Knoop microhardness and FT-Raman spectroscopic evaluation of a resin-based dental material light-cured by an Argon ion laser and halogen lamp: An in vitro study. Photomedicine and Laser Surgery 2008;26:531-39.
  27. Polymerization depth of contemporary light-curing units using microhardness. J Esthet Dent 2000;12:340-49.
  28. Conversion in different depths of ultraviolet and visible light activated composite materials. Acta Odontol Scand 1982;40:179-92.
  29. The relationship between cure depth and transmission coefficient of visible-lightactivated resin composites. J Dent Res 1994;73:516-21.
  30. Relevance of different polymerisation methods on light-curing composites conversion degree. J Dent Res 2009;88(Sp Iss A):(Abstr 301).
  31. Degree of conversion and post-gel shrinkage of low shrinkage composites. J Dent Res 2010;89(Sp Iss B):(Abstr 319).
  32. Contraction stress of low-shrinkage composite materials assessed with different testing systems. Dent Mater 2010;26:947-53.
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