Abstract
Objectives:Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights.Materials and Methods:DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were placed in Teflon molds and cured from the top. The thermocouple under samples recorded the temperature rise. After initial radiation and specimens reaching the ambient temperature, reirradiation was done and temperature was recorded again. Both temperature rise and DC data submitted to one-way ANOVA and Tukey-HSD tests (5% significance).Results:The obtained results revealed that DC was not significantly different between the understudy composite resins or curing units. Low shrinkage composite resin showed a significantly higher temperature rise than hybrid composite resin. Argon laser caused the lowest temperature rise among the curing units.Conclusion:Energy density of light curing units was correlated with the DC. Type of composite resin and light curing unit had a significant effect on temperature rise due to polymerization and curing unit, respectively.
Highlights
Dental treatments often cause temperature rise in dental pulp
This study sought to assess the degree of conversion (DC) and temperature rise in two different dental composite resins: Filtek Z250 and Filtek P90 using light-emitting diode (LED) and argon laser light curing units (LCUs)
The similar energy density of different light sources is responsible for similar Degree of conversion (DC) at the surface of composite resin samples [18]
Summary
Dental treatments often cause temperature rise in dental pulp. Heat may be generated by the application of different methods and materials such as rotary instruments and polymerization of dental composite resins [1, 2].Composite resins are among the commonly used dental materials in restorative dentistry [3]. Dental treatments often cause temperature rise in dental pulp. Heat may be generated by the application of different methods and materials such as rotary instruments and polymerization of dental composite resins [1, 2]. Composite resins are among the commonly used dental materials in restorative dentistry [3]. A generation of so-called low-shrink composites (silorane) has been introduced that promises a significant reduction in polymerization shrinkage [4]. Silorane resins are derivatives of siloxane and oxirane monomers composed of a hydrophobic siloxane backbone with oxirane rings. These monomers polymerize with a cationic ring opening and provide reduced shrinkage [5]
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