title: Margin gap size of ceramic inlays using second-generation CAD/CAM equipment.
abstract: OBJECTIVE
  The goal of this study was to determine if the fit of second-generation computer-assisted design/computer-assisted manufacturing (CAD/CAM) (CEREC 2, Sirona Dental Systems, Bensheim, Germany) inlays within Class II cavity preparations were within the range of 50 to 100 microns and were equal or better to CEREC 1 inlays.
  
  
  METHODS
  Extracted human molars free of surface defects and caries were prepared with standard mesio-occlusodistal cavity preparations. Ceramic inlays were fabricated with CEREC 2 CAD/CAM equipment and seated into cavity preparations. Digital images were captured at 100 times magnification. Marginal gaps were measured with an image analysis program. For each restoration, gaps were measured at 12 locations along interproximal margins and 10 locations along occlusal margins.
  
  
  RESULTS
  No difficulty occurred in seating any of the milled inlays. Average marginal gaps for occlusal (59 +/- 35 microns) and interproximal (97 +/- 66 microns) margins were statistically different (t-test, p < or = .01). Average marginal gap for all sites combined was 80 +/- 57 microns. Marginal gap widths were smaller than those obtained from a similar study done earlier with the CEREC 1 unit for occlusal (89 +/- 65 microns) and interproximal (105 +/- 81 microns) margins. Ease of seating with CEREC 2 inlays was much better than with CEREC 1.
  
  
  CONCLUSIONS
  Improvements in software and hardware allow the CEREC 2 to adapt well to standard inlay cavity preparations. The ability of the device to create inlays that seat without interference is remarkable. The improved fit and ability to create the occlusal surface in a variety of ways make CEREC 2 an attractive restorative option for all-ceramic restorations.
authors.affiliation: University of North Carolina School of Dentistry, Chapel Hill, USA. John_Sturdevant@dentistry.unc.edu
authors.forename: J R
authors.initials: JR
authors.lastname: Sturdevant
authors.forename: S C
authors.initials: SC
authors.lastname: Bayne
authors.forename: H O
authors.initials: HO
authors.lastname: Heymann
mesh_terms: D002516:Ceramics; D017076:Computer-Aided Design / Q000295:instrumentation*; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain; D017267:Dental Prosthesis Design / Q000295:instrumentation*; D006801:Humans; D007284:Inlays; D008963:Molar; D017755:Prosthesis Fitting
chemical_list: D003776:Dental Porcelain; C074543:Cerec