title: Enhanced compatibility and initial stability of Ti6Al4V alloy orthodontic miniscrews subjected to anodization, cyclic precalcification, and heat treatment.
abstract: OBJECTIVE
  To evaluate the bioactivity, and the biomechanical and bone-regenerative properties of Ti6Al4V miniscrews subjected to anodization, cyclic precalcification, and heat treatment (APH treatment) and their potential clinical use.
  
  
  METHODS
  The surfaces of Ti6Al4V alloys were modified by APH treatment. Bioactivity was assessed after immersion in simulated body fluid for 3 days. The hydrophilicity and the roughness of APH-treated surfaces were compared with those of untreated (UT) and anodized and heat-treated (AH) samples. For in vivo tests, 32 miniscrews (16 UT and 16 APH) were inserted into 16 Wistar rats, one UT and one APH-treated miniscrew in either tibia. The miniscrews were extracted after 3 and 6 weeks and their osseointegration (n = 8 for each time point and group) was investigated by surface and histological analyses and removal torque measurements.
  
  
  RESULTS
  APH treatment formed a dense surface array of nanotubular TiO2 layer covered with a compact apatite-like film. APH-treated samples showed better bioactivity and biocompatibility compared with UT and AH samples. In vivo, APH-treated miniscrews showed higher removal torque and bone-to-implant contact than did UT miniscrews, after both 3 and 6 weeks (p < 0.05). Also, early deposition of densely mineralized bone around APH-treated miniscrews was observed, implying good bonding to the treated surface.
  
  
  CONCLUSIONS
  APH treatment enhanced the bioactivity, and the biomechanical and bone regenerative properties of the Ti6Al4V alloy miniscrews. The enhanced initial stability afforded should be valuable in orthodontic applications.
authors.affiliation: Sun Dental Hospital, Daejeon, Korea.
authors.forename: Eun-Ju
authors.initials: EJ
authors.lastname: Oh
authors.affiliation: Department of Dental Biomaterials and Institute of Oral Bioscience, Brain Korea 21 Project, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Thuy-Duong T
authors.initials: TD
authors.lastname: Nguyen
authors.affiliation: Department of Orthodontics, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Seung-Youp
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Orthodontics, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Jeon
authors.affiliation: Department of Dental Biomaterials and Institute of Oral Bioscience, Brain Korea 21 Project, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Tae-Sung
authors.initials: TS
authors.lastname: Bae
authors.affiliation: Department of Orthodontics, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Jong-Gee
authors.initials: JG
authors.lastname: Kim
keywords: Biocompatibility; Orthodontic mini-implant; Stability; Surface treatment