title: Evaluation of surface roughness as a function of multiple blasting processing variables.
abstract: OBJECTIVE
  This study evaluated the effect of implant surface blasting variables, such as blasting media size, velocity, and surface coverage and their two- and three-way interaction in surface roughness parameters.
  
  
  METHODS
  Machined, grade IV titanium-alloy implants (n = 180) had their surfaces treated by a combination of 36 different blasting protocols according to the following variables: aluminum oxide blasting media particle size (50, 100, and 150 μm); velocity (75, 100, 125, and 150 m/s), and surface coverage (5, 15, 25 g/in.(2) ) (n = 5 per blasting protocol). A single 0.46 inch nozzle of the blaster was pointed at the threaded area and spaced 0.050 inches away. Surface topography (n = 5 measurements per implant) was assessed by scanning electron microscopy. Roughness parameters Sa, Sq, Sdr, and Sds were evaluated by optical interferometry. A GLM statistical model evaluated the effects of blasting variables on the surface parameters, and their two- and three-way interaction (P < 0.05). Statistical inferences for Sa and Sq were performed after a log(10)  transformation to correct for data skewness.
  
  
  RESULTS
  Prior to the log(10)  transformation, Sa and Sq values for all processing groups ranged from ~0.5 to ~2.6 μm and from ~0.75 to 4 μm, respectively. Statistical inferences showed that Sa, Sq, and Sdr values were significantly dependent on blasting media, velocity, and surface coverage (all P < 0.001). Media × velocity, media × coverage, and media × velocity × coverage also significantly affected Sa, Sq, and Sdr values (P < 0.002). The highest levels were obtained with 100 μm blasting media, coverage for 5 g/in.(2) , and velocity of 100 m/s. No significant differences were observed for Sds (P > 0.15).
  
  
  CONCLUSIONS
  The blasting variables produced different surface topography features and knowledge of their interaction could be used to tailor a desired implant surface configuration.
authors.affiliation: Department of Prosthodontics and Operative Dentistry, Tufts University School of Dental Medicine, Boston, MA, USA.
authors.forename: Guilherme B
authors.initials: GB
authors.lastname: Valverde
authors.forename: Ryo
authors.initials: R
authors.lastname: Jimbo
authors.forename: Hellen S
authors.initials: HS
authors.lastname: Teixeira
authors.forename: Estevam A
authors.initials: EA
authors.lastname: Bonfante
authors.forename: Malvin N
authors.initials: MN
authors.lastname: Janal
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D000537:Aluminum Oxide; D003722:Dental Alloys; D045662:Dental Etching / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014025:Titanium
chemical_list: D003722:Dental Alloys; D015921:Dental Implants; D014025:Titanium; D000537:Aluminum Oxide