Hydroxylation of dental zirconia surfaces: Characterization and bonding potential

Abstract

Bioinert zirconia surfaces exhibit a low chemical bonding potential to resin-based luting agents. The aim was to hydroxylate dental zirconia surfaces and to examine tensile bond strength using commercial luting agents. The measured bond strength was compared with established mechanical conditioning techniques. Five acidic and one alkaline hydroxylation pretreatments were applied and compared with air abrasion and tribochemical silica coating. For the chemical characterization of hydroxyl groups and hydroxyl value, zirconia powders were used, chemically modified, and analyzed using Fourier-transformed infrared spectroscopy and a titrimetric method according to the ISO 4629 standard. All acidic pretreatment procedures exhibited increased hydroxyl values. The highest values were recorded after treatment with phosphoric acid or Piranha solution. Tensile bond strength was examined in a universal testing machine using the commercial dual-cure luting agents Multilink (Ivoclar, Liechtenstein) and Panavia F2.0 (Kuraray, Japan). Surface hydroxylation with Piranha solution in combination with the luting agent Multilink led to a bond strength of 12.47 +/- 3.25 MPa. Tribochemical silica-coated/silanized zirconia surfaces with Multilink produced the highest bond strength of 19.33 +/- 3.65 MPa. Using the luting agent Panavia F2.0, statistically homogenous values for the untreated (11.60 +/- 1.68 MPa) and for the hydroxylated surface (12.46 +/- 3,81 MPa) were measured. Bioinert zirconia surfaces were successfully hydroxylated in terms of tensile bond strength. Resin bonding with Multilink can be strongly increased by acidic treatment with Piranha solution. Bonding with Panavia F2.0 is not affected by hydroxylation, which is likely due to the incorporation of specific functional monomers.

The Impact of Plasma Treatment of Cercon® Zirconia Ceramics on Adhesion to Resin Composite Cements and Surface Properties

“…[3][4][5][6] Despite these advantages, it is hard to obtain a proper bonding to other substrates because of its hydrophobic surface. 7,8 Several studies have shown that unmodified surfaces display low bond strength and eventually leads to adhesive failure, [9][10][11] so there is a need to intensify surface properties of these ceramics to reach an effective bonding. 12 These surface modifications are based on roughening the surface and increasing its wettability.…”

Evaluation of Chemical Treatment on Zirconia Surface with Two Primer Agents and an Alkaline Solution on Bond Strength

“…Although the loss of retention has never been a topic of interest with Y-TZP restorations (because it has never been reported), efforts have been undertaken to establish ways to achieve a reliable bond between Y-TZP crowns and luting agents. [22][23][24][25][26][27][28][29][30][31][32][33][34] Comparatively, data from a literature review 11 showed a 2.8% loss of retention rate in all-ceramic systems (except for zirconia) after five years, while for a metal-ceramic system the loss of retention rate decreases to 0.7% after 10 years. 35 Thus, the effective bond strength between the substrate and ceramic plays an important role in enhancing the longevity of restorative treatments 25,29,[36][37][38][39][40] and in preventing microleakage.…”

Bonding of Resin Materials to All-Ceramics: A Review

“…Acidic treated with Piranha solution also created hydroxylation at Zirconia surface, which strongly increased the bond strength between zircon and resin cements, such as Multilink (Ivoclar Vivadent). However, it didn't improve MDP-containing resin cement, Panavia F2.0 (Kuraray) (Lohbauer et al, 2008). The laser treatments, such as erbium: yttriumaluminum-garnet (Er: YAG) Er: YAG and neodymium:: yttrium-aluminum-garnet (Nd: YAG) laser, significantly increased the bond strength of Zirconia, while CO (2) laser treatment was less effective for improving Zirconia bonding (Akin et al, 2011;Paranhos et al, 2011).…”