Ultrashort-pulse laser as a surface treatment for bonding between zirconia and resin cement

• Published in: Dental materials 2019-11, Vol.35 (11), p.1545-1556
• Main Authors: Abu Ruja, Mahmood, De Souza, Grace M., Finer, Yoav
• Format: Article
• Language: English
• Subjects: Adhesion tests; Alumina blasting; Aluminum oxide; Blasting; Bond strength; Bonding strength; Contact angle; Crystalline phases; Cytotoxicity; Dental Bonding; Dental cement; Dental restorative materials; Dentistry; Lasers; Lymphocytes T; Materials Testing; Microtensile bond strength; Resin Cements; Resins; Shear Strength; Silica; Silicon dioxide; Slabs; Surface characterization; Surface Properties; Surface roughness; Surface treatment; Surface wettability; Tetragonal zirconia; Tetragonal zirconia polycrystals; Thermal cycling; Thermocycling; Tribochemical silica coating; Wettability; X-ray diffraction analysis; Y-TZP; Yttria-stabilized zirconia; Yttrium; Yttrium oxide; Zirconia; Zirconium; Zirconium dioxide
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2019.07.009

•Ultrashort-pulse laser improves bond strength of zirconia to resin cements.•Ultrashort-pulse laser did not alter crystalline phase content of zirconia.•Thermocycling affects bond strength in a surface treatment dependent manner. To evaluate ultrashort-pulse laser (UPL) as a surface treatment for improved bond strength to Yttria-tetragonal zirconia polycrystalline (Y-TZP). Fully-sintered Y-TZP samples received either no treatment (CTL), or were treated by alumina blasting (ALB), tribochemical silica coating (SIL), or one of two UPL patterns: multiple pulses laser surface dots with 2.5μm spacing (8mJ, 10kHz)(LSD); or single pulse laser surface lines with 2.5μm spacing (4mJ, 6.7kHz)(LSL). Surface roughness, wettability (contact angle), and quantification of crystalline phases were evaluated for each group (n=3/group). Y-TZP treated slabs were cemented to resin composite slabs using silane and 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing adhesive. Beams from the Y-TZP/resin blocks were microtensile tested (n=5/group) after 48h water incubation (37°C) with or without subsequent thermocycling (5–55°C, 5000 cycles). All surface treatments increased surface roughness values versus control (PSIL: 19.95±3.99MPa=ALB: 19.51±2.55MPa>CTL: 14.51±2.23MPa). Thermocycling significantly reduced bond strength for all treatments in a surface treatment-dependent manner. The ability of UPL to alter Y-TZP surface morphology, increase wettability and μTBS without increasing the monoclinic content suggests its potential to improve bonding to the underlying resin cement and tooth without compromising the strength of the restoration.