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.

Citations

Citations to this article as recorded by  

• Degree of Conversion and Polymerization Shrinkage of Low and High Viscosity Bulk-Fill Giomer-based and Resin-based composites
  Heera Kim, Jaesik Lee, Hyunjung Kim, Taeyub Kwon, Soonhyeun Nam
  THE JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY.2019; 46(1): 1.     CrossRef
• Effect of the exponential curing of composite resin on the microtensile dentin bond strength of adhesives
  So-Rae Seong, Duck-kyu Seo, In-Bog Lee, Ho-Hyun Son, Byeong-Hoon Cho
  Journal of Korean Academy of Conservative Dentistry.2010; 35(2): 125.     CrossRef

The purpose of present study was to evaluate the polymerization shrinkage stress and amount of linear shrinkage of composites and compomers for posterior restoration.

For this purpose, linear polymerization shrinkage and polymerization stress were measured.

For linear polymerization shrinklage and polymerization stress measurement, custom made Linometer (R&B, Daejon, Korea) and Stress measuring machine was used (R&B, Daejon, Korea). Compositers and compomers were evaluated; Dyract AP (Dentsply Detrey, Gumbh. German) Z100 (3M Dental Products, St. Paul, USA) Surefil (Dentsply Caulk, Milford, USA) Pyramid(Bisco, Schaumburg, USA) Synergy Compact (Coltene, Altstatten, Switzerland), Heliomolar (Vivadent/Ivoclar, Liechtenstein), and Compoglass (Vivadent Ivoclar/Liechtenstein) were used. 15 measurements were made for each material. Linear polymerization shrinkage or polymerization stress for each material was compared with one way ANOVA with Tukey at 95% levels of confidence.

For linear shrinkage; Heliomolar, Surefil<Synergy Compact, Z100<Dyract AP<Pyramid, Compoglass F (p<0.05)

For Shrinkage stress; Heliomolar<Z100, Pyramid<Synergy Compact, Compoglass F<Dyract AP<Heliomolar HB, Surefil (p<0.05)

Citations

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• A comparative study on color and dimensional stability of esthetic indirect dental materials
  Hye-Yun Heo, Hyo-Jin Son, Yu-Ri Heo, Mee-Kyoung Son
  Oral Biology Research.2019; 43(4): 306.     CrossRef
• Measurement of the Internal Adaptation of Resin Composites Using Micro-CT and Its Correlation With Polymerization Shrinkage
  HJ Kim, SH Park
  Operative Dentistry.2014; 39(2): e57.     CrossRef
• Comparison of Premolar Cuspal Deflection in Bulk or in Incremental Composite Restoration Methods
  ME Kim, SH Park
  Operative Dentistry.2011; 36(3): 326.     CrossRef
• Effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resin
  Min Kyung Kim, Sung Ho Park, Deog Gyu Seo, Yun Jung Song, Yoon Lee, Chan Young Lee
  Journal of Korean Academy of Conservative Dentistry.2008; 33(4): 341.     CrossRef
• Correlation Between the Amount of Linear Polymerization Shrinkage and Cuspal Deflection
  S-Y. Lee, S-H. Park
  Operative Dentistry.2006; 31(3): 364.     CrossRef
• Correlation between Linear polymerization shrinkage & tooth cuspal deflection
  Soon-Young Lee, Sung-Ho Park
  Journal of Korean Academy of Conservative Dentistry.2005; 30(6): 442.     CrossRef

Ormocer has organic-inorganic compound polymers. One of advantages of ormocer is reduced polymerization shrinkage. The purpose of this study was to compare the amount of contraction shrinkage of composite resins and ormocers. Additionally, the time of each material when there is no further change of contraction shrinkage was analysed.

Four brands of composite resins (P-60, Surefil, Z-250 and Denfil) and two brands of ormocers (Definite and Admira) were used. 20 seconds, 40 seconds and 60 seconds of curing times were given. Contraction shrinkage of them were measured using a linometer for 80 seconds.

The effect of material and curing time to contraction shrinkage at the time of 80 seconds was analysed by two-way ANOVA. The effect of time to contraction shrinkage was analysed by one-way ANOVA, and the time when there was no further change of the contraction shrinkage was analysed. The results are as follows :

P-60, Definite, Z-250 and Denfil had no further change of contraction shrinkage from the time of 20 seconds, and Surefil and Admira had no further change of contraction shrinkage from the time of 10 seconds.

Citations

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• Polymerization shrinkage and stress analysis during dental restoration observed by digital image correlation method
  Jung-Hoon Park, Nak-Sam Choi
  Journal of Mechanical Science and Technology.2021; 35(12): 5435.     CrossRef
• Acoustic emission characteristics of methacrylate-based composite and silorane-based composite during dental restoration according to a variety of C-factor
  Jung-Hoon Park, Ja-Uk Gu, Nak-Sam Choi
  Journal of Mechanical Science and Technology.2017; 31(9): 4067.     CrossRef
• Behavior of Polymerization Shrinkage Stress of Methacrylate-based Composite and Silorane-based Composite during Dental Restoration
  Jung-Hoon Park, Nak-Sam Choi
  Composites Research.2015; 28(1): 6.     CrossRef