Warning: mkdir(): Permission denied in /home/virtual/lib/view_data.php on line 81

Warning: fopen(upload/ip_log/ip_log_2024-12.txt): failed to open stream: No such file or directory in /home/virtual/lib/view_data.php on line 83

Warning: fwrite() expects parameter 1 to be resource, boolean given in /home/virtual/lib/view_data.php on line 84
Polymerization shrinkage of composite resins cured by variable light intensities


Your browser does not support the NLM PubReader view.

Go to this page to see a list of supporting browsers.

Polymerization shrinkage of composite resins cured by variable light intensities

Article information

Restor Dent Endod. 2007;32(1):28-36
Publication date (electronic) : 2007 January 31
doi : https://doi.org/10.5395/JKACD.2007.32.1.028
Mi-Young Lim1, Kyung-Mo Cho2, Chan-Ui Hong1
1Department of Conservative Dentistry, School of Dentistry Dankook University, Korea.
2Department of Conservative Dentistry, School of Dentistry Kangnung National University, Korea.
Corresponding Author: Chan-Ui Hong. Department of Conservative Dentistry, College of Dentistry, Dankook University, 7-1 Shinbu-dong, Cheonan, Korea. Tel: 82-41-550-1964, Fax: 82-41-550-1963, endohong@hanmail.net
Received 2006 December 04; Revised 2006 December 15; Accepted 2006 December 28.

Abstract

The purpose of this study was to compare the effect of exponential curing method with conventional curing and soft start curing method on polymerization shrinkage of composite resins.

Three brands of composite resins (Synergy Duo Shade, Z250, Filtek Supreme) and three brands of light curing units (Spectrum 800, Elipar Highlight, Elipar Trilight) were used. 40 seconds curing time was given. The shrinkage was measured using linometer for 90 seconds.

The effect of time on polymerization shrinkage was analysed by one-way ANOVA and the effect of curing modes and materials on polymerization shrinkage at the time of 90s were analysed by two-way ANOVA. The shrinkage ratios at the time of 20s to 90s were taken and analysed the same way. The results were as follows:

1. All the groups except Supreme shrank almost within 20s. Supreme cured by soft start and exponential curing had no further shrinkage after 30s (p < 0.05).

2. Statistical analysis revealed that polymerization shrinkage varied among materials (p = 0.000) and curing modes (p = 0.003). There was no significant interaction between material and curing mode.

3. The groups cured by exponential curing showed the statistically lower polymerization shrinkage at 90s than the groups cured by conventional curing and soft start curing (p < 0.05).

4. The initial shrinkage ratios of soft start and exponential curing were statistically lower than conventional curing (p < 0.05).

From this study, the use of low initial light intensities may reduce the polymerization rate and, as a result, reduce the stress of polymerization shrinkage.

Keywords: Polymerization shrinkage; Light intensities; Soft start; Exponential curing; Linometer; Polymerization rate

References

1. Sakaguchi RL, Peters MCRB, Nelson SR, Douglas W, Poort HW. Effects of polymerization contraction in composite restorations. J Dent 1992. 20178–182.
2. Attin T, Buchalla W, Kielbassa AM, Helwig E. Curing shrinkage and volumetric changes of resin modified glass ionomer restorative materials. Dent Mater 1995. 11359–389.
3. de Gee AJ, Feilzer AJ, Davidson CL. True linear polymerization shrinkage of unfilled resins and composite determined with a linometer. Dent Mater 1993. 911–14.
4. Venhoven BA, de Gee AJ, Davidson CL. Polymerization contraction and conversion of light-curing BisGMA-based methacrylate resins. Biomaterials 1993. 14871–875.
5. Davidson CL, Feilzer AJ. Polymerization shrinkage and polymerization shrinkage stress in polymer-based restoratives. J Dent 1997. 25435–440.
6. Dennison JB, Yaman P, Seir R, Hamilton JC. Effects of variable light intensity on composite shrinkage. J Prosthet Dent 2000. 84499–505.
7. Stansbury JW. Synthesis and evaluation of new oxaspiro monomers for double ring opening polymerization. J Dent Res 1992. 711408–1412.
8. Lim BS, Lee YG, Kim CW. Polymerization shrinkage stress. J Korea Res Soc Dent Mater 2001. 2881–94.
9. Silikas N, Eliades G, Watts DC. Light intensity effects on resin composite degree of conversion and shrinkage strain. Dent Mater 2000. 16(4)292–296.
10. Lim BS, Ferracane JL, Sakaguchi RL, Codon JR. Reduction of polymerization contraction stress for dental composites by two step light activation. Dent Mater 2002. 18436–444.
11. Yoon TH, Lee YG, Lim BS, Kim CW. Effect of irradiation method on the polymerization shrinkage od dental esthetic restorative materials. J Korea Res Soc Dent Mater 2000. 27(4)307–315.
12. Versluis A, Tantbirojn D, Douglas WH. Do dental composites always shrink toward the light? J Dent Res 1998. 771435–1445.
13. Uno S, Asmussen E. Marginal adaptation of a restorative resin polymerized at reduced rate. Scand J Dent Res 1991. 99440–444.
14. Unterbrink GL, Muessner R. Influence of light intensity on two restorative systems. J Dent 1995. 23183–189.
15. Goracci G, Mori G, de'Martinis LG. Curing light intensity and marginal leakage of resin composite restorations. Quintessence Int 1996. 27355–362.
16. Kanca J, Suh BI. Pulse activation: Reducing resin based composite contraction stresses at the enamel cavosurface margins. Am J Dent 1999. 12107–112.
17. Yap AU, Soh MS, Siow KS. Post gel shrinkage with pulse activation and soft start polymerization. Oper Dent 2002. 2781–87.
18. Lee YG, Yoon TH, Kim CW. A Study on the polymerization shrinkage and thermal expansion of dental esthetic restorative materials. J Korea Res Soc Dent Mater 2000. 27171–179.
19. Iga M, Takeshige F, Ui T, Torii M, Tsuchitani Y. The relationship between polymerization shrinkage measured by a modified dilatometer and the inorganic filler content of light-cured composites. Dent Mater J 1991. 1038–45.
20. Bandyopadhyay S. A study of the volumetric setting shrinkage of some dental materials. J Biomed Mater Res 1982. 16135–144.
21. Hay JN, Shortall AC. Polymerization contraction and reaction kinetics of three chemically activated restorative resins. J Dent 1988. 16172–176.
22. Grajower R, Guleman M. Dimensional changes during setting of a glass ionomer filling material. Quintessence Int 1989. 20505–511.
23. Dauvillier BS, Aarnts M, Feilzer AJ. Developments in shrinkage control of adhesive restoratives. J Esthet Dent 2000. 12291–299.
24. Park SH, Krejci I, Lutz F. Consistency in the amount of linear polymerization shrinkage in syringe type composites. Dent Mater 1999. 15442–446.
25. Bouschlicher MR, Vargas MA, Boyer DB. Effect of composite type, light intensity, configuration factor and laser polymerization on polymerization contraction forces. Am J Dent 1997. 1088–96.
26. Feilzer AJ, de Gee AJ, Davidson CL. Quantitative determination of stress reduction by flow in composite restorations. Dent Mater 1990. 6167–171.
27. Dauvillier BS, Aarnts MP, Feilzer AJ. Developments in shrinkage control of adhesive restorations. J Esthet Dent 2000. 12291–299.
28. Davidson CL, Davidson-Kaban SS. Handling of mechanical stresses in composite restorations. Dent update 1998. 25274–279.
29. Koran P, Kurschner R. Effect of sequential versus continuous irradiation of a light cured resin composite on shrinkage, viscosity, adhesion, and degree of polymerization. Am J Dent 1998. 1117–22.
30. Bouschlicher MR, Rueggeberg FA. Effect of ramped light intensity on polymerization force and conversion in a photoactivated composite. J Esthet Dent 2000. 12328–339.
31. Kinomoto Y, Torii M, Takeshige F, Ebisu S. Comparison of polymerization contraction stresses between self and light curing composites. J Dent 1999. 27383–389.
32. Peutzfeldt A. the monomer systems. Eur J Oral Sci 1997. 10597–116.

Article information Continued

Copyright © 2007 Korean Academy of Conservative Dentistry
(open-access) :

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Figure 1

Figure 1

Diagram of linometer.

Figure 2

Figure 2

Linear polymerization shrinkage of Synergy Duo Shade.

Figure 3

Figure 3

Linear polymerization shrinkage of Filtek Z250.

Figure 4

Figure 4

Linear polymerization shrinkage of Filtek Supreme.

Table 1

Linear polymerization shrinkage after 90 seconds with various curing modes (%)

Table 1

Table 2

Two-factor analysis of variance for linear shrinkage at 90 seconds

Table 2

Table 3

Homogeneous subsets of materials and curing modes at 90 seconds

Table 3

Table 4

Linear polymerization shrinkage (%) at 20s and 90s and their ratio (%)(S.D)

Table 4

Table 5

Two-factor analysis of variance for initial shrinkage ratios

Table 5

Table 6

Homogeneous subsets of materials and curing modes of initial shrinkage ratios

Table 6