A zinc-doped endodontic cement facilitates functional mineralization and stress dissipation at the dentin surface

• Manuel Toledano ^[1] ; Raquel Osorio ^[1] ; Mayra C. Pérez-Álvarez ^[3] ; Estrella Osorio ^[1] ; Christopher D. Lynch ^[2] ; Manuel Toledano-Osorio ^[1]
  1. [1] Universidad de Granada

     Universidad de Granada

     Granada, España

     
  2. [2] University College Cork

     University College Cork

     Irlanda

     
  3. [3] DDS, PhD, Professor. University of La Havana, Biomaterials Department. San Lázaro y L. Municipio Plaza de la Revolución. La Havana- Cuba

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• Localización: Medicina oral, patología oral y cirugía bucal. Ed. inglesa, ISSN-e 1698-6946, Vol. 23, Nº. 6 (November ), 2018
• Idioma: inglés
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  • The purpose of this study was to evaluate nanohardness and viscoelastic behavior of dentin surfaces treated with two canal sealer cements for dentin remineralization.

    Dentin surfaces were subjected to: i) 37% phosphoric acid (PA) or ii) 0.5 M ethylenediaminetetraacetic acid (EDTA) conditioning prior to the application of two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite), respectively. Samples were stored in simulated body fluid during 24 h or 21 d. The intertubular and peritubular dentin were evaluated using a nanoindenter to assess nanohardness (Hi). The load/displacement responses were used for the nano-dynamic mechanical analysis to estimate complex modulus (E*) and tan delta (δ). The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. AFM imaging and FESEM analysis were performed.

    After 21 d of storage, dentin surfaces treated with EDTA+calcypatite, PA+calcypatite and EDTA+oxipatite showed viscoelastic discrepancies between peritubular and intertubular dentin, meaning a risk for cracking and breakdown of the surface. At both 24 h and 21 d, tan δ values at intertubular dentin treated with the four treatments performed similar. At 21 d time point, intertubular dentin treated with PA+oxipatite achieved the highest complex modulus and nanohardness, i.e., highest resistance to deformation and functional mineralization, among groups.

    Intertubular and peritubular dentin treated with PA+oxipatite showed similar values of tan δ after 21 d of storage. This produced a favorable dissipation of energy with minimal energy concentration, preserving the structural integrity at the dentin surface.