Effect of Different LED Light-curing Units on Degree of Conversion and Microhardness of Bulk-fill Composite Resin

ABSTRACT Dental chair lights have been known to rapidly polymerize lightcured composites beyond the point of workability. Often in our dental clinics we are advised to switch off the dental chair light while light curing of dental composites. The purpose of this study was to determine whether the dental chair light causes any effect on the degree of polymerization of light cured composites using the quartz tungsten halogen (QTH) and the light emitting diode (LED) light curing units (LCUs). Filtek Z350 composite samples of 2 × 5 mm were prepared in an acrylic mold. Four groups were made having 20 samples each. In group I and II light curing was done using QTH LCU with and without the dental chair light respectively. Similarly in group III and IV LED LCU was used. Microhardness was measured and compared using Knoop's hardness Test. Data was submitted to ANOVA and Tukey's test. Results showed that the average microhardness was significantly higher in group 4 (LED light curing with dental chair light on). Thus, it was concluded that the dental chair light can be left on while using QTH and LED LCU's during light curing of composite material. How to cite this article Parekh B, Sathe S, Hegde V. Analysis of the Effect of Dental Chair Light on the Knoop Hardness of Composite Resin While Light Curing with QTH and LED Light Units. World J Dent 2012;3(2):156-160.

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A study on the degree of conversion of light curing composite resin according to the thickness of tooth structure penetrated by light and applied light curing time

The Journal of Korean Academy of Conservative Dentistry ◽

10.5395/jkacd.2002.27.1.016 ◽

2002 ◽

Vol 27 (1) ◽

pp. 16 ◽

Cited By ~ 1

Author(s):

Kee-Hwan Hwang ◽

In-Ho Jang ◽

Se-Joon Lee ◽

Kwang-Won Lee

Keyword(s):

Composite Resin ◽

Degree Of Conversion ◽

Curing Time ◽

Tooth Structure ◽

Light Curing

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Effects of distance from tip of LED light-curing unit and curing time on surface hardness of nano-filled composite resin

Journal of Physics Conference Series ◽

10.1088/1742-6596/884/1/012095 ◽

2017 ◽

Vol 884 ◽

pp. 012095

Author(s):

V A Shafadilla ◽

M Usman ◽

A Margono

Keyword(s):

Composite Resin ◽

Surface Hardness ◽

Curing Time ◽

Led Light ◽

Light Curing ◽

Filled Composite

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Effect of LED and Argon Laser on Degree of Conversion and Temperature Rise of Hybrid and Low Shrinkage Composite Resins

The Open Dentistry Journal ◽

10.2174/1874210601610010538 ◽

2016 ◽

Vol 10 (1) ◽

pp. 538-545 ◽

Cited By ~ 3

Author(s):

Ayob Pahlevan ◽

Masumeh Hasani Tabatabaei ◽

Sakineh Arami ◽

Sara Valizadeh

Keyword(s):

Energy Density ◽

Temperature Rise ◽

Composite Resin ◽

Argon Laser ◽

Composite Resins ◽

Degree Of Conversion ◽

Light Curing ◽

Higher Temperature ◽

Laser Curing ◽

One Way Anova

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.

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The effect of a plastic-wrapped LED light curing unit and curing distance variances on diametral tensile strength of composite resin

Journal of Physics Conference Series ◽

10.1088/1742-6596/1073/4/042008 ◽

2018 ◽

Vol 1073 ◽

pp. 042008

Author(s):

R H F Zaini ◽

A Soufyan ◽

B Irawan ◽

M Damiyanti

Keyword(s):

Tensile Strength ◽

Composite Resin ◽

Led Light ◽

Light Curing ◽

Diametral Tensile Strength

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Effect of the Time of Salivary Contamination during Light Curing on Degree of Conversion and Microhardness of a Restorative Composite Resin

Biomimetics ◽

10.3390/biomimetics3030023 ◽

2018 ◽

Vol 3 (3) ◽

pp. 23 ◽

Cited By ~ 1

Author(s):

Rasoul Sahebalam ◽

Alireza Boruziniat ◽

Fahimeh Mohammadzadeh ◽

Abdolrasoul Rangrazi

Keyword(s):

Composite Resin ◽

Clinical Problem ◽

Human Saliva ◽

Point Of View ◽

Composite Resins ◽

Degree Of Conversion ◽

Dental Composite ◽

Dental Composite Resins ◽

Light Curing ◽

Saliva Contamination

Saliva contamination is a major clinical problem in restorative procedures. The purpose of this study was to evaluate the effect of the time of salivary contamination during light curing on the degree of conversion and the microhardness of a restorative composite resin. Eight groups of 10 samples for measuring the microhardness and eight groups of 5 samples for evaluating the degree of conversion were prepared. The samples of each group were contaminated with human saliva at a certain time. The first group (T0) was contaminated before light curing. The specimens in groups T2–T30 were contaminated at 2, 5, 10, 15, 20 and 30 s after the start of light curing, respectively. The samples of group T40 were contaminated after light curing. The degree of conversion and the microhardness of the specimens were measured by Fourier transform infrared (FTIR) spectroscopy and Vickers hardness testing techniques, respectively. The results of this study revealed that there were no significant differences between the groups in terms of the degree of conversion of the composite resin. Consistent with the findings for the degree of conversion, significant differences in the microhardness between the groups were not found. In conclusion, from a clinical point of view, the results of our study showed that the time of salivary contamination (before, during or after light curing of composite resin) has no significant effect on the polymerization (degree of conversion) and one of the important mechanical properties of dental composite resins (microhardness).

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