Microhardness of nanofilled composite resin light-cured by LED or QTH units with different times

Authors

  • Ana Isabelle Salvador Groninger University of Campinas
  • Giulliana Panfiglio Soares University of Campinas
  • Robson Tetsuo Sasaki University of Campinas
  • Glaucia Maria Bovi Ambrosano University of Campinas
  • José Roberto Lovadino University of Campinas
  • Flávio Henrique Baggio Aguiar University of Campinas

DOI:

https://doi.org/10.20396/bjos.v10i3.8641629

Keywords:

Composite resins, Hardness

Abstract

Aim: To evaluate the influence of light-curing units and light-curing time on the microhardness of a nanofilled composite resin. Methods: Forty-five composite resin (Z350 - 3M) specimens were randomly prepared using Teflon ring molds (4.0 mm internal diameter and 2 mm depth) and divided into nine experimental groups (n=5): three polymerization units (conventional - 450 mW/ cm2 ; 2nd generation LED - 1100 mW/cm2 ; and 3rd generation LED - 700 mW/cm2 ) and three lightcuring times (20 s, 40 s, and 60 s). All specimens were polymerized with the light-curing tip positioned 8 mm far from the top surface of the specimen. After 24 h, Knoop microhardness measurements were made on the top and bottom surfaces of the specimen, with a load of 10 g for 10 s. Five indentations were made on each surface. All results were analyzed statistically by subdivided parcel ANOVA (Split-Plot) and Tukey’s tests (p<0.05). Results: There were no statistically significant differences for the polymerization unit and light-curing time factors in either top or bottom surface. For all experimental conditions, the top surfaces showed greater hardness than the bottom surfaces (p<0.0001). Conclusions: The mode of polymerization and the lightcuring time did not affect the hardness of the nanofilled composite resin, and increasing the lightcuring time did not improve the hardness of the bottom surface of the composite resin.

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Author Biographies

Ana Isabelle Salvador Groninger, University of Campinas

Undergraduate student, Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas

Giulliana Panfiglio Soares, University of Campinas

DDS, MS, PhD student, Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas

Robson Tetsuo Sasaki, University of Campinas

DDS, MS student, Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas

Glaucia Maria Bovi Ambrosano, University of Campinas

DDS, MS, PhD, Assistant Professor, Department of Community Dentistry and Statistics, Piracicaba Dental School, University of Campinas

José Roberto Lovadino, University of Campinas

DDS, MS, PhD, Chairman, Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas

Flávio Henrique Baggio Aguiar, University of Campinas

DDS, MS, PhD, Assistant Professor, Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas

Published

2015-11-09

How to Cite

1.
Groninger AIS, Soares GP, Sasaki RT, Ambrosano GMB, Lovadino JR, Aguiar FHB. Microhardness of nanofilled composite resin light-cured by LED or QTH units with different times. Braz. J. Oral Sci. [Internet]. 2015 Nov. 9 [cited 2022 Sep. 30];10(3):189-92. Available from: https://periodicos.sbu.unicamp.br/ojs/index.php/bjos/article/view/8641629

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