title: [Preliminary evaluation of clinical effect of computer aided design and computer aided manufacture zirconia crown].
abstract: OBJECTIVE
  To evaluate clinical effects of computer aided design and computer aided manufacturing (CAD/CAM) milled zirconia crown in three aspects: aesthetic, contact wear and fracture.
  
  
  METHODS
  Sixty patients were divided into two groups.In one group, 35 full contour CAD/CAM zirconia crown were made on molars of 30 patients. The manufacturing process of zirconia crown was as follow. First, the three dimensional(3-D) data of working models, antagonist impression and check records were acquired by 3-D laser scanning Dental wings S50. Then full contour zirconia crowns, which had functional occlusal contacts with antagonistic teeth, and appropriate contact with adjacent teeth were designed with Zeno-CAD(V4.2.5.5.12919) software. ZENOSTAR Zr pure zirconia material was milled in digital controlled machine WIELAND 4030 M1.In the end, the zirconia crown were completed with the method of second sintering and polishing. After clinical try-in, the crown was cemented.In the control group, thirty gold alloy full crown were made and cemented on molars of 30 patients. According to the modified U S Public Health Service Criteria(USPHS) evaluation standard, all crowns were evaluated on the same day, at three months, half a year, one year and two years following delivery. There were three aspects we were focusing on in the evaluation: aesthetic, contact wear(restoration and antagonist), and fracture.
  
  
  RESULTS
  In all the prosthesis we evaluated during the 24 months, no fracture was found. Contact wear of crowns varies according to different antagonist teeth.
  
  
  CONCLUSIONS
  The zirconia crowns show privilege in aesthesis, toughness and anti-wearing.However, there is contact wear on antagonistic natural teeth. Thus it is a good choice when full zirconia crowns are indicated on two antagonistic teeth in both jaws.
authors.affiliation: Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry, Ministry of Health, Beijing 100081, China.
authors.forename: Yu-guang
authors.initials: YG
authors.lastname: Wang
authors.forename: Yan-xi
authors.initials: YX
authors.lastname: Xing
authors.forename: Yu-chun
authors.initials: YC
authors.lastname: Sun
authors.forename: Yi-jiao
authors.initials: YJ
authors.lastname: Zhao
authors.forename: Pei-jun
authors.initials: PJ
authors.lastname: Lü
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D017076:Computer-Aided Design; D003442:Crowns; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D019554:Dental Restoration Wear; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar; D055815:Young Adult; D015040:Zirconium
chemical_list: D003776:Dental Porcelain; D015040:Zirconium