title: Reduced wear of enamel with novel fine and nano-scale leucite glass-ceramics.
abstract: OBJECTIVE
  Leucite glass-ceramics used to produce all-ceramic restorations can suffer from brittle fracture and wear the opposing teeth. High strength and fine crystal sized leucite glass-ceramics have recently been reported. The objective of this study is to investigate whether fine and nano-scale leucite glass-ceramics with minimal matrix microcracking are associated with a reduction in in vitro tooth wear.
  
  
  METHODS
  Human molar cusps (n=12) were wear tested using a Bionix-858 testing machine (300,000 simulated masticatory cycles) against experimental fine crystal sized (FS), nano-scale crystal sized (NS) leucite glass-ceramics and a commercial leucite glass-ceramic (Ceramco-3, Dentsply, USA). Wear was imaged using Secondary Electron Imaging (SEI) and quantified using white-light profilometry.
  
  
  RESULTS
  Both experimental groups were found to produce significantly (p<0.05) less volume and mean-height tooth loss compared to Ceramco-3. The NS group had significantly (p<0.05) less tooth mean-height loss and less combined (tooth and ceramic) loss than the FS group. Increased waviness and damage was observed on the wear surfaces of the Ceramco-3 glass-ceramic disc/tooth group in comparison to the experimental groups. This was also indicated by higher surface roughness values for the Ceramco-3 glass-ceramic disc/tooth group.
  
  
  CONCLUSIONS
  Fine and nano-sized leucite glass-ceramics produced a reduction in in vitro tooth wear. The high strength low wear materials of this study may help address the many problems associated with tooth enamel wear and restoration failure.
authors: Centre for Adult Oral Health, Barts and the London, School of Medicine and Dentistry, Queen Mary University of London, Turner Street, London E1 2AD, UK. a.theocharopoulos@ucc.ie
authors: Antonios
authors: A
authors: Theocharopoulos
authors: Xiaohui
authors: X
authors: Chen
authors: Robert
authors: R
authors: Hill
authors: Michael J
authors: MJ
authors: Cattell
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D001732:Bite Force; D002516:Ceramics / Q000737:chemistry*; D003461:Crystallography; D003743:Dental Enamel / Q000473:pathology*; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008409:Mastication / Q000502:physiology; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D013499:Surface Properties; D019228:Tooth Crown / Q000473:pathology; D057085:Tooth Wear / Q000517:prevention & control*
chemical_list: D000538:Aluminum Silicates; D003776:Dental Porcelain; C078519:leucite; C023506:Glass ceramics; C058233:Ceramco