title: Effect of newly Developed Resin Cements and Thermocycling on the Strength of Porcelain Laminate Veneers.
abstract: OBJECTIVE
  The aim of this study was to determine the effect of different luting cements and accelerated artificial aging (AAA) in the fracture resistance of porcelain laminate veneers (PLVs).
  
  
  METHODS
  A total of 80 disc-shaped specimens were prepared using computer-aided design/computer-aided milling technology from lithium disilicate glass-ceramic blocks. Specimens (0.5 mm thick, 10 mm diameter) were divided into eight groups of 10 specimens per group. The control groups consisted of specimens without cement and not subjected to AAA (CN group) and specimens prepared without cement but subjected to AAA (CW group). The experimental groups were subjected to AAA and cemented with Variolink Veneer, Variolink Esthetic LC, Variolink Esthetic DC, RelyX Unicem, RelyX Veneer, or RelyX Ultimate. Specimens were individually tested for biaxial flexure on a universal testing machine. One-way analysis of variance and the Tukey's post hoc test were used to compare the groups' significance statistically (α = 0.05).
  
  
  RESULTS
  The loads to fracture (LTF) values in the CN group were higher than those in the CW and experimental groups. The lowest LTF value was in the CW group (31.5 ± 9.5 N) and the highest LTF value in the CN group (56.7 ± 10.6 N). Tukey's post hoc test demonstrated a statistically significant (p < 0.01) difference between the CN group and the other groups.
  
  
  CONCLUSIONS
  Artificial aging had a significant effect on the LTF value of the tested specimens compared with the resin cements used. Cohesive failure within the PLVs was the most common mode of failure.
  
  
  CONCLUSIONS
  Fatigue strength of dental ceramics and moisture was shown to affect the mechanical properties of all-ceramic restorations. All-ceramic material is extremely sensitive to humidity and thermocycling.
authors.affiliation: Department of Prosthetic Dental Science, Division of Prosthodontics, College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj, Kingdom of Saudi Arabia, Phone: +966115886201, e-mail: implantologist@yahoo.com.
authors.forename: Fawaz I
authors.initials: FI
authors.lastname: Alqahtani
mesh_terms: D017076:Computer-Aided Design; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003801:Dental Veneers; D006801:Humans; D019279:Resin Cements / Q000627:therapeutic use*
chemical_list: D019279:Resin Cements; D003776:Dental Porcelain
keywords: Ceramic restoration; Fracture resistance; Laminate veneer; Loads to fracture; Porcelain veneer Thermocycling.