Effect of Different Polymerization Methods on the Cytotoxicity of Dental Composites

Objectives: The aim of this study was to compare the cytotoxic effects of various dental composites polymerized with two different curing units.

Methods: Disc-shaped test samples of composites Filtek Z250, Filtek A110, Filtek P60, Filtek Supreme, and SDI Rok were polymerized using one quartz tungsten halogen (QTH) and one light emitting diode (LED) light curing unit (LCU), namely Optilux 501 (QTH) and Elipar Freelight 2 (LED). L-929 mouse fibroblast cultures (3x104 cells/ml) were incubated with the samples in 96 well culture plates for evaluation after 8, 24, 48, 72 h. At the end of each period, the cells were counted and examined under a light microscope, and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay was performed. The degree of cytotoxicity for each sample was determined according to the reference value represented by the cells in a control group (a culture without sample).

Results: A significant 3 factor interaction occurred among LCUs, composites, and time factors (P<.005). In general, the test materials cured with the LED LCU demonstrated higher cell survival rates when compared with those cured with halogen LCUs.

Conclusions: This study shows that polymerization of dental composites with a light emitting diode LCU positively influences the L-929 mouse fibroblast cell viability. (Eur J Dent 2010;4:287-292)

Keywords

Cytotoxicity - Dental composite - Light curing units

• REFERENCES

• 1 Davidson CL, Feilzer AJ. Polymerization shrinkage and polymerization shrinkage stress in polymer-based restoratives. J Dent 1997; 25: 435-440
• 2 Moon HJ, Lee YK, Lim BS, Kim CW. Effects of various light curing methods on the leachability of uncured substances and hardness of a composite resin. J Oral Rehabil 2004; 31: 258-264
• 3 Engelmann J, Leyhausen G, Leibfritz D, Geurtsen W. Metabolic effects of dental resin components in vitro detected by NMR spectroscopy. J Dent Res 2001; 80: 869-875
• 4 Geurtsen W. Substances released from dental resin composites and glass ionomer cements. Eur J Oral Sci 1998; 106: 687-695
• 5 Ferracane JL, Greener EH. Fourier transform infrared analysis of degree of polymerization in unfilled resins-methods comparison. J Dent Res 1984; 63: 1093-1095
• 6 Bouillaguet S, Virgillito M, Wataha J, Ciucchi B, Holz J. The influence of dentine permeability on cytotoxicity of four dentine bonding systems, in vitro. J Oral Rehabil 1998; 25: 45-51
• 7 Heil J, Reifferscheid G, Waldmann P, Leyhausen G, Geurtsen W. Genotoxicity of dental materials. Mutat Res 1996; 368: 181-194
• 8 Lindberg A, Peutzfeldt A, van JWDijken. Effect of power density of curing unit, exposure duration and light guide distance on composite depth of cure. Clin Oral Investig 2005; 9: 71-76
• 9 Uhl A, Mills RW, Jandt KD. Photoinitiator dependent composite depth of cure and Knoop hardness with halogen and LED light curing units. Biomaterials 2003; 24: 1787-1795
• 10 Murray PE, Garcia CGodoy, Garcia FGodoy. How is the biocompatibilty of dental biomaterials evaluated?. Med Oral Patol Oral Cir Bucal 2007; 12: E258-266
• 11 Bean TA, Zhuang WC, Tong PY, Eick JD, Chappelow CC, Yourtee DM. Comparison of tetrazolium colorimetric and 51Cr release assays for cytotoxicity determination of dental biomaterials. Dent Mater 1995; 11: 327-331
• 12 Cao T, Saw TY, Heng BC, Liu H, Yap AU, Ng ML. Comparison of different test models for the assessment of cytotoxicity of composite resins. J Appl Toxicol 2005; 25: 101-108
• 13 Nalcaci A, Oztan MD, Yilmaz S. Cytotoxicity of composite resins polymerized with different curing methods. Int Endod J 2004; 37: 151-156
• 14 Sigusch BW, Volpel A, Braun I, Uhl A, Jandt KD. Influence of different light curing units on the cytotoxicity of various dental composites. Dent Mater 2007; 23: 1342-1348
• 15 Tseng WY, Huang CH, Chen RS, Lee MS, Chen YJ, Rueggeberg FA. et al Monomer conversion and cytotoxicity of dental composites irradiated with different modes of photoactivated curing. J Biomed Mater Res B Appl Biomater 2007; 83: 85-90
• 16 Uhl A, Sigusch BW, Jandt KD. Second generation LEDs for the polymerization of oral biomaterials. Dent Mater 2004; 20: 80-87
• 17 Goldberg M. In vitro and in vivo studies on the toxicity of dental resin components: a review. Clin Oral Investig 2008; 12: 1-8
• 18 Quinlan CA, Zisterer DM, Tipton KF, O'Sullivan MI. In vitro cytotoxicity of a composite resin and compomer. Int Endod J 2002; 35: 47-55
• 19 Geurtsen W, Spahl W, Leyhausen G. Residual monomer/ additive release and variability in cytotoxicity of light-curing glass-ionomer cements and compomers. J Dent Res 1998; 77: 2012-2019