Influence of intracoronal bleaching agents on the ultimate strength and ultrastructure morphology of dentine

  1. V. Cavalli1,
  2. M. S. Shinohara2,
  3. W. Ambrose3,
  4. F. M. Malafaia4,
  5. P. N. R. Pereira5,
  6. M. Giannini6

Article first published online: 8 MAY 2009

DOI: 10.1111/j.1365-2591.2009.01543.x

Issue

International Endodontic Journal

International Endodontic Journal

Volume 42, Issue 7, pages 568–575, July 2009

Additional Information

How to Cite

Cavalli, V., Shinohara, M. S., Ambrose, W., Malafaia, F. M., Pereira, P. N. R. and Giannini, M. (2009), Influence of intracoronal bleaching agents on the ultimate strength and ultrastructure morphology of dentine. International Endodontic Journal, 42: 568–575. doi: 10.1111/j.1365-2591.2009.01543.x

Author Information

  1. 1

    Division of Operative Dentistry, Department of Dentistry, University of Taubaté, Taubaté, SP

  2. 2

    Division of Operative Dentistry, Department of Dentistry, State University of Amazonas, Manus, AM, Brazil

  3. 3

    School of Dentistry, Electron Microscopy Facility, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA

  4. 4

    Division of Prosthodontics, Department of Dentistry, University of Taubaté, Taubaté, SP, Brazil

  5. 5

    Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA;

  6. 6

    Division of Operative Dentistry, Department of Restorative Dentistry, Piracicaba School of Dentistry, University of Campinas, Piracicaba, SP, Brazil

*Prof. Dr Marcelo Giannini, Faculdade de Odontologia de Piracicaba, Av. Limeira, 901 – 13414-903 Piracicaba, SP, Brazil (Tel.: +55-19-2106-5338; fax: +55-19-2106-5218; e-mail: giannini@fop.unicamp.br).

Publication History

  1. Issue published online: 1 JUN 2009
  2. Article first published online: 8 MAY 2009
  3. Received 29 February 2008; accepted 17 December 2008

SEARCH

SEARCH BY CITATION

ARTICLE TOOLS

View Full Article (HTML) Get PDF (229K)

Keywords:

  • dentine;
  • intracoronal bleaching;
  • ultimate tensile strength;
  • ultrastructure

Abstract

Objective  To evaluate the effects of intracoronal bleaching on ultimate tensile strength (UTS) of sound and etched dentine and its ultrastructure morphology.

Methodology  Bovine dentine specimens with (e) or without previous etching with 37% phosphoric acid for 15 s were used for the intracoronal bleaching experiments. Teeth were randomly assigned to five treatments (n = 10): (C) control – no bleaching, (SP) sodium perborate, (CP) 35% carbamide peroxide, (25% HP) 25% hydrogen peroxide and (35% HP) 35% hydrogen peroxide. Bleaching was performed four times within a 72 h interval and afterwards, dentine pulp chamber blocks were obtained. The blocks were sectioned in 0.7 mm-thick slices and these were trimmed to reduce the inner dentine to a dumbbell shape with a cross-sectional area of 0.8 mm2. Specimens were tested with the microtensile method (0.5 mm min−1) and data were analysed (two-way anova-Tukey test, P < 0.05). Additional teeth were prepared for transmission electron microscopy (TEM) to evaluate dentine ultramorphology.

Results  The mean values of the UTS (SD) in MPa for sound dentine were: C = 48.3(8.5)a, SP = 34.6 (8.2)b, CP = 32.9 (8.9)b, 25% HP = 28.0(4.6)b, 35% HP = 26.4(6.6)b, and pre-etched dentine: Ce = 38.9(13.8)a, SPe = 31.3 (9.3)ab, CPe = 28.4 (6.2)ab, 25% HPe = 30.0 (7.9)ab, 35% HPe =  19.9(4.6)b. Significant differences between the means are indicated by the letters. TEM observations exhibited demineralization areas for all bleaching treatments.

Conclusion  Bleaching decreased dentine UTS after treatment. Pre-etched not-bleached dentine (Ce) presented UTS similar to pre-etched bleached dentine, except for 35% HPe. The decrease of UTS of bleached dentine could be attributed to ultrastructural alterations such as loss of inorganic components.

View Full Article (HTML) Get PDF (229K)