Abstract
Objectives 10-methacryloyloxydecyldihydrogenphosphate (MDP) containing primers improve bonding of yttria-stabilised tetragonal zirconia (Y-TZP) to methacrylate resins. The present study investigated the role played by water in the deterioration of MDP-mediated zirconia-resin bonds. Methods Grit-blasted Y-TZP plates were conditioned with two MDP primers and bonded with resin for shear bond strength (SBS) testing. Additional bonded plates were aged hydrothermally and compared with unaged Y-TZP after 24 h of water-storage or 6 months of water/acid/alkali-storage. The monoclinic phase (m–ZrO2) in different groups was determined by X-ray diffraction. Hydrolytic stability of the coordinate bond between MDP and zirconia in neutral/acid/alkaline environment was analysed using thermodynamic calculations. Microleakage and release of the element phosphorus from MDP-mediated Y-TZP/resin-bonded interfaces were evaluated via methylene blue dye infiltration and inductively coupled plasma-mass spectrometry (ICP-MS). Results Hydrothermal ageing did not significantly alter SBS. Ageing in acidic or neutral medium led to significant decline in SBS. The m–ZrO2 phase increased after hydrothermal ageing but no m–ZrO2 was detected in the water/acid/alkali-aged specimens. A higher equilibrium constant was identified in the MDP–t–ZrO2 complex when compared with the MDP–m–ZrO2 complex. MDP-conditioning failed to prevent infiltration of the methylene blue dye. Phosphorus was detected by ICP-MS from the solutions used for soaking the resin-bonded specimens. Conclusions Hydrolysis of the coordinate bond between MDP and ZrO2, rather than t → m phase transformation, weakens the bond integrity between MDP-conditioned Y-TZP and methacrylate resin. Clinical significance Hydrolysis of the coordinate bond between MDP and zirconia is responsible for deterioration of the integrity of the bond between MDP-conditioned Y-TZP and methacrylate resin.
Original language | English (US) |
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Pages (from-to) | 23-29 |
Number of pages | 7 |
Journal | Journal of Dentistry |
Volume | 64 |
DOIs | |
State | Published - Sep 2017 |
Keywords
- Adhesion
- MDP
- Phosphate resin monomer
- Primer
- Surface treatment
ASJC Scopus subject areas
- General Dentistry