title: Biomechanical and histomorphometric properties of four different mini-implant surfaces.
abstract: OBJECTIVE
  To investigate the effects of surface roughness on the removal torque and bone-to-implant contact of four different orthodontic mini-implants.
  
  
  METHODS
  Mini-implants and circular discs were made from alloy Ti6Al4V grade 5. On the basis of surface treatment, the study was divided into four groups-group 1: machined (n = 32), no surface treatment; group 2: acid etched (n = 32), with hydrochloric acid; group 3 (n = 32), grit blasted with alumina; and group 4, grit blasted + acid etched (n = 32). Mean surface roughness (Ra) and quadratic average roughness (Rq) from each group were measured two dimensionally in non-contact mode by the optical profilometer. Contact angle measurement of discs from each group was done with a contact angle goniometer. Contact angle of liquids with different hydrophobicity and hydrophilicity was measured: 1. highly hydrophilic liquid sodium chloride (NaCl), 2. lightly hydrophobic liquid dimethylsulfoxide, 3. distilled water, and 4. human blood. One hundred and twenty-eight miniscrews, differing in surface treatment, were placed into the tibias and femurs of adult male New Zealand white rabbits. Rabbits were euthanized after 8 weeks and removal torque and bone-to-implant contact were measured.
  
  
  RESULTS
  Surface roughness of group 3 was significantly greater than other groups (P < 0.05). Group 4 had significantly lower contact angle measurements, both for blood and sodium chloride (NaCl; 40.26 degrees, 27.20 degrees) when compared to other three groups (P ≤ 0.01). Group 4 had significantly higher torque and bone-to-implant contact than group 3 (P = 0.007), group 2 (P = 0.003), and group 1 (P = 0.0002).
  
  
  CONCLUSIONS
  Surface roughness and wettability of mini-implants influence their biological response.
authors: *Division of Orthodontics, University of Connecticut Health Center, Farmington, CT and yadav_sumit17@yahoo.com.
authors: Sumit
authors: S
authors: Yadav
authors: *Division of Orthodontics, University of Connecticut Health Center, Farmington, CT and.
authors: Madhur
authors: M
authors: Upadhyay
authors: Department of Oro-facial Genetics, Indiana University-Purdue University, Indianapolis, IN, USA.
authors: Wilbur Eugene
authors: WE
authors: Roberts
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000497:Alloys; D000537:Aluminum Oxide / Q000737:chemistry; D000818:Animals; D001696:Biomechanical Phenomena; D001769:Blood; D000069343:Bone-Implant Interface / Q000033:anatomy & histology*; D003722:Dental Alloys / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D015921:Dental Implants; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D005269:Femur / Q000601:surgery; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D008297:Male; D008422:Materials Testing; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D011817:Rabbits; D011897:Random Allocation; D012965:Sodium Chloride / Q000737:chemistry; D013499:Surface Properties; D013977:Tibia / Q000601:surgery; D014025:Titanium / Q000737:chemistry; D019415:Torque; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; D014867:Water; C031462:titanium alloy (TiAl6V4); D012965:Sodium Chloride; D014025:Titanium; D000537:Aluminum Oxide; D006851:Hydrochloric Acid; D004121:Dimethyl Sulfoxide