Dental Materials
Volume 22, Issue 3 , Pages 203-210, March 2006

Effect of the composite photoactivation mode on microtensile bond strength and Knoop microhardness

  • André L.F. e Silva

      Affiliations

    • Department of Restorative Dentistry, Piracicaba School of Dentistry, University of Campinas, Piracicaba, SP, Brazil
    • ,
  • Gisele D.S. Pereira

      Affiliations

    • School of Dentistry, Gama Filho University, Rio de Janeiro, RJ, Brazil
    • ,
  • Carlos T.S. Dias

      Affiliations

    • ESALQ, University of São Paulo, Piracicaba, SP, Brazil
    • ,
  • Luís Alexandre Maffei Sartini Paulillo

      Affiliations

    • Department of Restorative Dentistry, Piracicaba School of Dentistry, University of Campinas, Piracicaba, SP, Brazil
    • Corresponding Author InformationCorresponding author. Address: Av. Limeira 901 Vila Areião, Faculdade de Odontologia de Piracicaba, Unicamp, Piracicaba, SP CEP 13414-903, Brazil. Tel.: +55 19 3412 5340; fax: +55 19 3412 5223.

Received 22 July 2004; received in revised form 5 February 2005; accepted 4 April 2005.

Summary 

Objective

This study evaluated the effect of the composite photoactivation mode on microtensile bond strength and Knoop microhardness.

Methods

Standard class I cavities (3×4×3mm) were restored with two adhesives systems, Single Bond (SB) and Clearfil SE Bond (CE), and the TPH composite. The photoactivation of the composite was carried out using three modes: Conventional (CO: 400mW/cm2×40s), Soft-Start (SS: 100mW/cm2×10s+600mW/cm2×30s) and Pulse-Delay (PD: 100mW/cm2×3s+3min wait+600mW/cm2×37s). For the microtensile test, beams obtained from the buccal wall bond interface were tested under tension at 0.5mm/min crosshead speed until failure. For the microhardness test, the restorations were sectioned in the mesio-distal direction and indentations were made on the internal composite surface of each half at three different depths. Data of two tests were analyzed using two-way ANOVA and LSMeans (α=0.05).

Results

In the microtensile test, SS presented the highest values. PD presented intermediate values without differing significantly from the other modes. For adhesives, SB presented the highest values. In the microhardness test, PD presented the highest values, differing significantly from SS. CO presented intermediate values but without any statistical difference from the others. The SS–CE interaction presented the lowest values with statistical differences from all the others.

Significance

By the SS technique, the highest bond strength was obtained. However, this technique made it possible for the adhesive system to intervene with the hardness of the composite.

Keywords: Photoactivation mode, Polymerization shrinkage, Adhesive system, Microtensile, Knoop microhardness

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PII: S0109-5641(05)00157-0

doi:10.1016/j.dental.2005.04.017

Dental Materials
Volume 22, Issue 3 , Pages 203-210, March 2006

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