Please cite this article in press as: M. Araújo, et al., Glass coatings on zirconia with enhanced bioactivity, J Eur Ceram Soc (2016), http://dx.doi.org/10.1016/j.jeurceramsoc.2016.04.042 ARTICLE IN PRESS G Model JECS-10642; No. of Pages 10 Journal of the European Ceramic Society xxx (2016) xxx–xxx Contents lists available at www.sciencedirect.com Journal of the European Ceramic Society journal homepage: www.elsevier.com/locate/jeurceramsoc Glass coatings on zirconia with enhanced bioactivity M. Araújo a,b , M. Miola c,∗,1 , A. Venturello c , G. Baldi b , J. Pérez a , E. Verné c a Colorobbia Espa˜ na S.A., Carretera CV-160, 12192 Vilafamés, Spain b Ce. Ri. Col, Centro Richerche Colorobbia, Via Pietramarina 123, 50053 Sovigliana, FI, Italy c Politecnico di Torino, Applied Science and Technology Department, Corso Duca degli Abruzzi 24, 10129 Torino, Italy a r t i c l e i n f o Article history: Received 2 March 2016 Received in revised form 13 April 2016 Accepted 30 April 2016 Available online xxx Keywords: Bioactive glasses Bioactivity Coatings Zirconia Prosthesis a b s t r a c t Highly bioactive glass coatings were successfully achieved by applying a newly developed bioactive glass layer having a low Ca/P ratio on a ZrO 2 -3%Y 2 O 3 ceramic substrate. The thermal properties of the glass allowed covering zirconia substrates both by amorphous and glass-ceramic coatings. The coatings exhib- ited 345 m thickness and were free from surface cracks, highlighting the good compatibility between the glass and the substrate in terms of expansion coefficient matching. The synthesized materials achieved the formation of a crystalline carbonate apatite layer after 3 days soaking in SBF solution. Although the slight diffusion of the amorphous and glass-ceramic coatings through the ZrO 2 -3%Y 2 O 3 support (≤20 m and ≤100 m, respectively), the rate of formation of carbonate apatite layer was maintained in compar- ison with the native glass alone, constituting a promising material for application as dental prosthetic devices. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Since zirconia was first used in ball heads for total hip replace- ments, tetragonal zirconia polycrystalline ceramics have been rapidly developed and applied as bone implants for surgery [1]. Zirconia stabilized in tetragonal phase with 3 mole percent (mol%) yittria (Y 2 O 3 ), referred to as yttria stabilized zirconia poly- crystalline ceramic (Y-TZP), has a flexural strength and fracture toughness that are almost twice those of the commonly used Al 2 O 3 [2]. Due to its interesting characteristics, the use of ZrO 2 - 3%Y 2 O 3 has been recently extended to prosthetic dentistry for the fabrication of crowns and fixed partial dentures [3,4]. Besides their excellent mechanical properties and biocompatibility, the tooth resembling color and enamel-like translucency make these materials potential candidates for the replacement of TiO 2 based prosthesis [5]. Although zirconia presents a biocompatibility and osteointegration similar to the one of titanium, the higher bioin- ertness of this material protects it not only from the attack by the several fermentation systems of the organisms, but also from degradation, providing a minimal ion release when compared with metallic implants [6–8]. It is well established that the release of ∗ Corresponding author at: Politecnico di Torino, Department of Applied Science and Technology (DISAT), Corso Duca degli Abruzzi 24, 10129 Torino, Italy. E-mail address: marta.miola@polito.it (M. Miola). 1 Present affiliation: Department of Health Sciences, Università del Piemonte Ori- entale “A. Avogadro”, Novara, Italy. ions from metallic implants is capable of producing several unde- sirable effects such as toxic, allergic, inflammatory and mutagenic reactions, as well as adverse tissue reactions close to dental cast. Furthermore, in vivo corrosion of the metallic implants can lead to reduction of the mechanical properties and consequent shorten- ing of the implant lifetime, as well as to harmful reactions to the host body, both locally and systemically, provided by the products of corrosion [9]. Another important advantage on the use of zirco- nia implants over the titanium ones consists on the lower bacteria accumulation, reducing the risk of inflammatory responses upon implantation [10]. Although biocompatible metallic and zirconia implants are strong, their ability to interact with the surrounding tissue is very low, leading to poor bone fixation [11,2]. When using bioinert materials, there is a relative movement and consequent progres- sive development of a non-adherent fibrous capsule in both soft and hard tissues. Movement at the biomaterial-tissue interface may guide to the increase of the thickness of this fibrous cap- sule and consequent implant loosening [12]. In these cases, cement is commonly used to provide the linking between the prosthetic material and the body. However, there is a high concern due to potential fragmentation and deterioration of the cement, leading to periprosthetic inflammation, progressive bone loss and eventual implant loosening. Although allografts, xenografts and autografts appear as valuable alternatives, some limitations related with these materials including poor bone induction properties, low rates of integration and possibility of immune rejection and viral transmis- http://dx.doi.org/10.1016/j.jeurceramsoc.2016.04.042 0955-2219/© 2016 Elsevier Ltd. All rights reserved.