Four-point bending evaluation of dentin-composite interfaces with various stresses

• Michal Staninec ^[1] ; Harrison Nguyen ^[1] ; Paul Kim ^[1] ; Grayson W. Marshall ^[1] ; R. O. Ritchie ^[1] ; Sally J. Marshall ^[1]
  1. [1] University of California, San Francisco

     University of California, San Francisco

     Estados Unidos

     
• Localización: Medicina oral, patología oral y cirugía bucal. Ed. inglesa, ISSN-e 1698-6946, Vol. 13, Nº. 1 (January), 2008
• Idioma: inglés
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• Resumen

  • Fracture properties of composite-dentin beams bonded with a self–etching adhesive were tested following short term pretreatments to simulate potential degradation mechanisms (thermal cycling, immersion in 5% NaOCl, or fatigue cycling). Beams of rectangular cross-section were shaped to a size of ~0.87 x 0.87 x 10 mm and placed in a four-point bending apparatus, with the loading points 1.8 and 7.2 mm apart, with the interface centered between the inner rollers. Testing was performed in Hanks’ Balanced Salt Solution at 25 ˚C .

    Solid dentin and solid composite beams [n = 6] had bending strengths of 164.4 and 164.6 MPa, respectively, under monotonically increasing loads. Bonded beams [n = 6] had strengths of 56.3 MPa. Thermo-cycling (5˚ to 55˚C), NaOCl solution immersion, or 105 of pre-fatigue cycles did not decrease the strength. Conclusion: Thermal stress, exposure to NaOCL, or 105 cycles of mechanical stress does not decrease bond strength of composite bonded to dentin as tested in four-point bending.