title: Effect of different dental ceramic systems on the wear of human enamel: An in vitro study.
abstract: BACKGROUND
  The wear of tooth structure opposing different advanced dental ceramic systems requires investigation.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to compare the wear of advanced ceramic systems against human enamel antagonists.
  
  
  METHODS
  Four ceramic systems (IPS e.max Press, IPS e.max CAD, Noritake Super Porcelain EX-3, and LAVA Plus Zirconia) and 1 control group containing human enamel specimens were used in this study (n = 12). All specimens were fabricated as disks 11 mm in diameter and 3 mm thick. The mesiopalatal cusps of the maxillary third molars were prepared to serve as the enamel styluses. All specimens were embedded individually in 25 mm(3) autopolymerizing acrylic resin blocks. Wear was measured with a cyclic loading machine and a newly designed wear simulator. All enamel styluses (cusps) were scanned using the Activity 880 digital scanner (SmartOptics). Data from the base line and follow-up scans were collected and compared with Qualify 2012 3-dimensional (3D) and 2D digital inspection software (Geomagic), which aligned the models and detected the geometric changes and the wear caused by the antagonist specimen. One-way ANOVA was used to analyze the collected data.
  
  
  RESULTS
  After 125,000 bidirectional loading cycles, the mean loss of opposing enamel volume for the enamel disks in the control group was 37.08 μm(3), the lowest mean value for IPS e.max Press system was 39.75 μm(3); 40.58 μm(3) for IPS e.max CAD; 45.08 μm(3) for Noritake Super Porcelain EX-3 system; and 48.66 μm(3) for the Lava Plus Zirconia system. No statically significant differences were found among the groups in opposing enamel volume loss (P=.225) or opposing enamel height loss (P=.149). In terms of opposing enamel height loss, Lava Plus Zirconia system showed the lowest mean value of 27.5 μm. The mean value for the IPS e.max CAD system was 27.91 μm; 29.08 μm for the control enamel; 33.25 μm for the IPS e.max Press system; and 34.75 μm for the Noritake Super Porcelain EX-3 system.
  
  
  CONCLUSIONS
  Within the limitations of this in vitro study, no differences were found in the linear and volumetric reduction of enamel cusps abraded against enamel disks and all other ceramic specimens. All ceramic systems exhibited high durability and were wear-friendly to opposing enamel.
authors.affiliation: Clinical Professor, Postgraduate Prosthodontics and Advanced Education in Esthetic and Operative Dentistry, Prosthodontic Division, Tufts University School of Dental Medicine, Boston, Mass. Electronic address: roya.zandparsa@tufts.edu.
authors.forename: Roya
authors.initials: R
authors.lastname: Zandparsa
authors.affiliation: Former resident, Advanced Education in Implant Dentistry, Tufts University School of Dental Medicine, Boston, Mass.
authors.forename: Rabie M
authors.initials: RM
authors.lastname: El Huni
authors.affiliation: Professor, Tufts University School of Dental Medicine, Boston, Mass.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirayama
authors.affiliation: President, Texture Technology Corporation, Hamilton, Mass.
authors.forename: Marc I
authors.initials: MI
authors.lastname: Johnson
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003743:Dental Enamel / Q000737:chemistry* / Q000473:pathology; D003775:Dental Polishing; D003776:Dental Porcelain; D019554:Dental Restoration Wear; D006801:Humans; D008422:Materials Testing; D013499:Surface Properties
chemical_list: D003776:Dental Porcelain