title: Wear of two artificial tooth materials in vivo: a 12-month pilot study.
abstract: BACKGROUND
  Wear of methacrylate artificial teeth resulting in vertical loss is a problem for both dentists and patients.
  
  
  OBJECTIVE
  The purpose of this study was to quantify wear of artificial teeth in vivo and to relate it to subject and tooth variables.
  
  
  METHODS
  Twenty-eight subjects treated with complete dentures received 2 artificial tooth materials (polymethyl methacrylate (PMMA)/double-cross linked PMMA fillers; 35%/59% (SR Antaris DCL, SR Postaris DCL); experimental 48%/46%). At baseline and after 12 months, impressions of the dentures were poured with improved stone. After laser scanning, the casts were superimposed and matched. Maximal vertical loss (mm) and volumetric loss (mm(3)) were calculated for each tooth and log-transformed to reduce variability. Volumetric loss was related to the occlusally active surface area. Linear mixed models were used to study the influence of the factors jaw, tooth, and material on adjusted (residual) wear values (alpha=.05).
  
  
  RESULTS
  Due to drop outs (n=5) and unmatchable casts (n=3), 69% of all teeth were analyzed. Volumetric loss had a strong linear relationship to surface area (P<.001); this was less pronounced for vertical loss (P=.004). The factor showing the highest influence was the subject. Wear was tooth dependent (increasing from incisors to molars). However, these differences diminished once the wear rates were adjusted for occlusal area, and only a few remained significant (anterior versus posterior maxillary teeth). Another influencing factor was the age of the subject.
  
  
  CONCLUSIONS
  Clinical wear of artificial teeth is higher than previously measured or expected. The presented method of analyzing wear of artificial teeth using a laser-scanning device seemed suitable.
authors: Department of Prosthodontics, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria. martina.schmid-schwap@meduniwien.ac.at
authors: Martina
authors: M
authors: Schmid-Schwap
authors: Valentin
authors: V
authors: Rousson
authors: Karin
authors: K
authors: Vornwagner
authors: Siegward D
authors: SD
authors: Heintze
mesh_terms: D000367:Age Factors; D019554:Dental Restoration Wear; D003824:Denture, Complete; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009066:Mouth, Edentulous / Q000534:rehabilitation; D010316:Particle Size; D010865:Pilot Projects; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D016628:Replica Techniques; D014093:Tooth, Artificial; D014716:Vertical Dimension
chemical_list: D019904:Polymethyl Methacrylate