title: Effect of various lasers on the bond strength of two zirconia ceramics.
abstract: OBJECTIVE
  The purpose of this study was to compare and evaluate the effects of various laser systems on surface roughness and shear bond strengths of zirconia ceramics.
  
  
  METHODS
  Seventy-two ceramic discs (10 mm×2 mm) obtained from two sintered zirconia ceramics (Zirkonzahn, Zirkonzahn Prettau(®)) were divided into two groups (n=36) according to the computer-aided design (CAD)-computer-aided manufacturing (CAM) technique and then further divided into three groups (n=12). Each group was treated with one of the following: (1) femtosecond (FS), (2) Nd:YAG (NY), and (3) Er:YAG (EY) lasers. After laser irradiation, a scanning electron micrograph (SEM) was taken at 500× magnification for qualitative examination. Following surface roughness measurement by profilometry, resin cement (Rely X U200) was bonded to the ceramic specimens using Teflon tubes (3 mm height, 4 mm diameter). Specimens were stored in distilled water at 37°C for 24 h and then thermal cycled for 5000 cycles. A shear bond strength (MPa) test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed by two way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) tests for pairwise comparisons among groups (p=0.05).
  
  
  RESULTS
  MPa and roughness were significantly affected by laser type (p<0.001), and there was no significant interaction between the two zircon ceramics. The group irradiated with FS laser had significantly higher (p<0.05) roughness and MPa mean values than those of the other groups. No significant difference was found between the groups irradiated with NY and EY laser (p>0.05). In the SEM, the surfaces of the FS group were rougher than those of the NY and EY groups. NY and EY surfaces were nearly smooth.
  
  
  CONCLUSIONS
  FS laser is an effective surface treatment for roughening surfaces of zirconia ceramics. Furthermore, it reveals the highest MPa.
authors: 1 Department of Prosthodontics, BezmialemVakif University , Faculty of Dentistry, Istanbul, Turkey .
authors: Ozlem
authors: O
authors: Kara
authors: Haluk Baris
authors: HB
authors: Kara
authors: Elif Sumeyye
authors: ES
authors: Tobi
authors: Atiye Nilgun
authors: AN
authors: Ozturk
authors: Hamdi Sukur
authors: HS
authors: Kilic
mesh_terms: D002516:Ceramics; D001840:Dental Bonding; D003764:Dental Materials; D003799:Dental Stress Analysis; D053844:Lasers, Solid-State; D028022:Low-Level Light Therapy; D008422:Materials Testing; D033081:Shear Strength; D013499:Surface Properties; D015040:Zirconium
chemical_list: D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide