Effect of grit-blasting air pressure on adhesion strength of resin to titanium Aftab Ahmed Khan a,n , Abdulaziz A. Al Kheraif a , Saleh Mohammed Alhijji b , Jukka Pekka Matinlinna c,d a Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia b Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia c Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China d Visiting Professor Program, King Saud University, Riyadh, Saudi Arabia article info Article history: Accepted 11 November 2015 Keywords: Adhesion Grit-blasting pressure Resin Silane primer Titanium abstract Aim: The objective of this laboratory study was to analyze the effect of different grit-blasting pressures on adhesion of resin to silica-coated and silanized Ti using the shear bond test. Materials and methods: A total of 24 commercially pure grade 2 Ti coupons (1 mm  20 mm  40 mm) were prepared and randomly assigned to 4 groups based on surface treatment: 150 kPa grit-blasting pressure with Rocatec TM Soft (group 1) for 10 s. Similarly, groups 2, 3 and 4 were treated at 280 kPa (control), 330 kPa and 380 kPa grit-blasting pressures, respectively, and followed by silanization. A total of 10 resin stubs per group were bonded onto each treated surface with photopolymerization. The shear bond strength was measured after 24 h dry storage in a desiccator, 2 months H 2 O storage, and 4 months H 2 O storage. Data were analyzed using descriptive statistics and two-way ANOVA (p o0.05). Results: After 24 h, initial SBS values of tested groups were significantly higher (32.0% for group 1, 39.1% for group 3, and 23.9% for group 4) than the control (group 2). After artificial aging, SBS values decreased in all the groups. The highest adhesion strength was seen in 150 kPa (13.0 73.0) and 280 kPa (4.9 72.4) after 2 months, and 4 months artificial aging, respectively. Conclusion: A lower grit-blasting pressure might promote adhesion strength in long term water aging. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction With the advent of advanced casting machines the use of titanium and titanium alloys has increased dramatically in den- tistry [1]. Titanium is being frequently used for crowns, dental implants, porcelain fused to metal (PFM) crowns, and as a frame work for CAD/CAM-milled fixed partial dentures [2]. Titanium and its alloys have excellent biocompatibility, high strength, low den- sity, and high corrosion resistance. In addition, veneering porce- lain can be fused and bonded to titanium surface in PFM restora- tions [3]. The popularity of using clinically titanium as a prosthetic restoration material has gained researchers' continuous interest in enhancing its adhesion strength with resin composite cements. Several methods have been employed to promote the adhe- sion strength of titanium with resins. Among them, tribochemical silica-coating (Rocatec TM ) is probably the most widely used [4]. This technique comprises silica modified grit-blasting particles followed by the application of a silane coupling agent. This pro- cess is called silanization [1]. Silanes which are bifunctional molecules help in forming a chemical bond between dissimilar materials with a silica layer on the titanium surface after silica- coating [5]. Silanization aims to provide increased surface free energy to improve surface wettability of the adhesive [6]. 3- Methacryloxyproyltrimethoxysilane (MPS) is the frequently used active silane monomer in commercially available dental silane primers [7], considered a “gold standard” for adhesion promotion between resins and silica coated metals [8]. However, studies on the effect of artificial aging i.e., thermo-cycling, water storage etc. on the predictability of long term adhesion (bond strength) are still needed [4]. On the other hand, the operating air pressure is a very impor- tant factor. The effect of grit-blasting pressure has been evaluated on resin to zirconia bonding. Heikkinen et al. suggested that higher adhesion strength of resin to zirconia was possible using a higher tribochemical operating pressure [9]. One can postulate that due to higher kinetic energy of the grit particles, higher sur- face roughness with increased embedding rate of the silica Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ijadhadh International Journal of Adhesion & Adhesives http://dx.doi.org/10.1016/j.ijadhadh.2015.11.003 0143-7496/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author. Tel.: þ966 59 1125997. E-mail addresses: aakjk@hotmail.com (A.A. Khan), aalkhuraif@ksu.edu.sa (A.A. Al Kheraif), smalhijji@ksu.edu.sa (S.M. Alhijji), jpmat@hku.hk (J.P. Matinlinna). International Journal of Adhesion & Adhesives 65 (2016) 41–46