title: Evaluation of a novel multiple phase veneering ceramic.
abstract: OBJECTIVE
  To produce a new veneering ceramic based on the production of a multiple phase glass-ceramic with improved performance in terms of strength and toughness.
  
  
  METHODS
  A composition of 60% leucite, 20% diopside and 20% feldspathic glass was prepared, blended and a heat treatment schedule of 930°C for 5 min was derived from differential thermal analysis (DTA) of the glasses. X-ray diffraction (XRD) and SEM analysis determined the crystalline phases and microstructure. Chemical solubility, biaxial flexural strength (BFS), fracture toughness, hardness, total transmittance and coefficient of thermal expansion (CTE) were all measured in comparison to a commercial veneering ceramic (VITA VM9). Thermal shock resistance of the leucite-diopside and VITA VM9 veneered onto a commercial high strength zirconia (Vita In-Ceram YZ) was also assessed. Statistical analysis was undertaken using Independent Samples t-test. Weibull analysis was employed to examine the reliability of the strength data.
  
  
  RESULTS
  The mean chemical solubility was 6 μg/cm(2) for both ceramics (P=1.00). The mean BFS was 109 ± 8 MPa for leucite-diopside ceramic and 79 ± 11 MPa for VITA VM9 ceramic (P=0.01). Similarly, the leucite-diopside ceramic demonstrated a significantly higher fracture toughness and hardness. The average total transmittance was 46.3% for leucite-diopside ceramic and 39.8% for VITA VM9 (P=0.01). The leucite-diopside outperformed the VITA VM9 in terms of thermal shock resistance. Significance This novel veneering ceramic exhibits significant improvements in terms of mechanical properties, yet retains a high translucency and is the most appropriate choice as a veneering ceramic for a zirconia base core material.
authors: Academic Unit of Restorative Dentistry, University of Sheffield, Sheffield S10 2TA, United Kingdom.
authors: Pannapa
authors: P
authors: Sinthuprasirt
authors: Academic Unit of Restorative Dentistry, University of Sheffield, Sheffield S10 2TA, United Kingdom.
authors: Richard
authors: R
authors: van Noort
authors: Academic Unit of Restorative Dentistry, University of Sheffield, Sheffield S10 2TA, United Kingdom.
authors: Robert
authors: R
authors: Moorehead
authors: Academic Unit of Restorative Dentistry, University of Sheffield, Sheffield S10 2TA, United Kingdom. Electronic address: s.pollington@sheffield.ac.uk.
authors: Sarah
authors: S
authors: Pollington
mesh_terms: D002516:Ceramics / Q000138:chemical synthesis*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003801:Dental Veneers; D006244:Hardness; D006358:Hot Temperature; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012824:Silicic Acid / Q000737:chemistry; D013499:Surface Properties; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry
chemical_list: D012824:Silicic Acid; C074224:diopside; C023506:Glass ceramics; D015040:Zirconium; C028541:zirconium oxide
keywords: BFS; Chemical solubility; Diopside; Fracture toughness; Glass–ceramic; Manufacture; Thermal shock resistance