title: Ceramic implant abutments: cutting efficiency and resultant surface finish by diamond rotary cutting instruments.
abstract: BACKGROUND
  There is no information regarding the cutting efficiency and the surface finish produced on ceramic implant abutments when using diamond rotary cutting instruments (DRCIs).
  
  
  OBJECTIVE
  The purpose of this study was to determine which DRCIs are the most efficient in cutting aluminum oxide and zirconium oxide implant abutments and to evaluate which DRCIs create the prepared ceramic abutment with the least surface roughness.
  
  
  METHODS
  A cutting regimen with a high-speed handpiece, 25 mL/min water spray and a 102.1-g load at the DRCI/ceramic interface was used to section the 4 x 4-mm edge of blocks of aluminum oxide (CerAdapt and Ceramic Esthetic Abutment) and zirconium oxide (Esthetic Zirconium Abutment (Nobel Biocare NB) and ZiReal Post (3i)) provided by the manufacturers. Two different brands of zirconium oxide were tested. Eight DRCIs of different types (Brasseler 2856, 5856, and 6856, Premier 770, TS2000, and Axis 856TSC, 856SC, and 856C) were tested to section each ceramic material 6 times, using a new block and a new DRCI for each test. The surface roughness (Ra value) was measured using a surface profilometer both parallel and perpendicular to the cut surface. Cutting efficiency was measured 3 times for change in weight/length of time (g/sec). The data were analyzed with a 1-way ANOVA and Tukey HSD tests (alpha=.05).
  
  
  RESULTS
  For the 3i zirconium oxide, 2 types of DRCIs (Axis 856 TSC and Brasseler 2856) produced a significantly smoother (P<.001 and P<.0001, respectively) surface finish on the shank and tip but not on the start and end. For the NB zirconium oxide, only the Axis 856C consistently produced a significantly smoother (P<.01, P<.0001 and P<.0001, respectively) surface finish on the start, shank, and tip. There was no significant difference in surface roughness of the NB aluminum oxide with use of any of the DRCIs. The Premier 770 was significantly more efficient (P<.0001 for 150 seconds and P<.001 for 300 seconds) in cutting the 3i zirconium oxide. The Premier 770 was significantly more efficient (P<.0001) in cutting the NB zirconium oxide at 150 seconds. The Premier TS2000 was significantly more efficient (P<.0001) at 300 seconds. The Axis 856 TSC was significantly more efficient (P<.0001 for 150 seconds and P<.001 for 300 seconds) in cutting the NB aluminum oxide.
  
  
  CONCLUSIONS
  For a smoother surface finish, Axis 856C should be used for the NB zirconium oxide abutment, and either Axis 856TSC or Brasseler 2856 should be used for the 3i zirconium oxide abutment. To complete gross reduction on the NB and 3i zirconium oxide abutments, Premier 770 and TS2000 were found to perform the best. Gross reduction on the aluminum oxide ceramic abutment from NB was most efficiently performed by Axis 856TSC.
authors.affiliation: Advanced Education Program in Prosthodontics, Baltimore College of Dental Surgery, University of Maryland, 21201, USA.
authors.forename: Si-Woon
authors.initials: SW
authors.lastname: Park
authors.forename: Carl F
authors.initials: CF
authors.lastname: Driscoll
authors.forename: Elaine E
authors.initials: EE
authors.lastname: Romberg
authors.forename: Sharon
authors.initials: S
authors.lastname: Siegel
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Thompson
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D000044:Dental Abutments; D003754:Dental High-Speed Equipment; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design / Q000295:instrumentation*; D018130:Diamond / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D012399:Rotation; D013499:Surface Properties; D013997:Time Factors; D015040:Zirconium / Q000737:chemistry
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D018130:Diamond; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide