title: Clinical performance and wear characteristics of veneered lithia-disilicate-based ceramic crowns.
abstract: OBJECTIVE
  The objectives of this study were to characterize the clinical performance and wear characteristics of lithia-disilicate-based ceramic crowns.
  
  
  METHODS
  Thirty posterior crowns were made using the heat-pressing technique and lithia-disilicate-based core ceramic. Subjects were recalled annually. The quality of crowns and adjacent gingival tissues were examined using nine criteria for acceptability. All crowns were examined and ranked from 4 (Excellent) to 1 (Unacceptable) for each criterion. Impressions were made for replica models at each appointment. Wear characteristics of dental ceramic and enamel were obtained by comparing the surface of the original model with the follow-up model using a laser scanner.
  
  
  RESULTS
  Twenty-nine subjects returned for the 1-year recall examination. The maximum clenching force for the 30 subjects ranged from 125 to 815 N. All clinical criteria were ranked good to excellent at the 1-year recall exam and no fractures were observed. The mean occlusal wear volumes for the ceramic crowns after 1 year were 0.19 (0.065)mm3 for premolar sites and 0.34 (0.08)mm3 for molar sites. The mean occlusal wear volumes of opposing enamel after 1 year were 0.21 (0.06)mm3 for premolar teeth and 0.50 (0.22)mm3 for molar teeth. The mean occlusal wear volume of ceramic molar crowns was significantly lower than the volume of enamel wear of the opposing teeth (p<or=0.05).
  
  
  CONCLUSIONS
  The quality of the overall prostheses and the gingival tissues were acceptable after 1 year. The mean occlusal wear volume of ceramic molar crowns was significantly lower than the enamel wear volume of the opposing teeth.
authors.affiliation: Prosthodontics Department, Faculty of Dentistry, Mahidol University, 6 Yothi Street, Prayathai, Bangkok 10400, Thailand. dtkst@mahidol.ac.th
authors.forename: Kallaya
authors.initials: K
authors.lastname: Suputtamongkol
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Anusavice
authors.forename: Chatcharee
authors.initials: C
authors.lastname: Suchatlampong
authors.forename: Phira
authors.initials: P
authors.lastname: Sithiamnuai
authors.forename: Chantana
authors.initials: C
authors.lastname: Tulapornchai
mesh_terms: D000328:Adult; D001641:Bicuspid / Q000473:pathology; D001732:Bite Force; D003442:Crowns / Q000592:standards; D003743:Dental Enamel / Q000473:pathology; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019554:Dental Restoration Wear; D003801:Dental Veneers; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000473:pathology; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D008963:Molar / Q000473:pathology; D011176:Post and Core Technique; D016628:Replica Techniques; D019217:Tooth Attrition / Q000473:pathology
chemical_list: C493120:lithia disilicate; D003776:Dental Porcelain