title: Effect of UV Photofunctionalization on Biologic and Anchoring Capability of Orthodontic Miniscrews.
abstract: OBJECTIVE
  Treatment of titanium with UV light immediately before use, or photofunctionalization, is gaining traction as a simple method to improve the biologic capability and clinical performance of dental implants. The objective of this study was to examine the effect of photofunctionalization on the biologic capability and mechanical anchorage of orthodontic miniscrews.
  
  
  METHODS
  Untreated and photofunctionalized Ti-6Al-4V orthodontic miniscrews were placed into rat femurs. Photofunctionalization was performed by treating miniscrews with UV light for 12 minutes using a photo device immediately before placement. After 3 weeks of healing, miniscrews were pushed laterally to measure the resistance against the tipping force. The miniscrews were also evaluated for morphology and chemistry of tissue formed around them using scanning electron microscopy and energy dispersive spectroscopy. Rat bone marrow-derived osteoblasts were cultured on Ti-6Al-4V disks with and without photofunctionalization. The number of osteoblasts attached to the disks and the behaviors, alkaline phosphatase activity, and mineralization capability of osteoblasts were evaluated.
  
  
  RESULTS
  Photofunctionalization converted both disk and screw surfaces from hydrophobic to superhydrophilic. In vivo biomechanical testing showed that the displacement of untreated screws was 1.5 to 1.7 times greater than that of photofunctionalized screws when subjected to lateral tipping force. Robust bone formation was observed around photofunctionalized miniscrews with strong elemental peaks of calcium and phosphorus, whereas the tissue around untreated miniscrews appeared thin and showed no clear peak of calcium. The attachment, initial spreading, adhesion, and expression of functional phenotypes of osteoblasts were significantly increased on photofunctionalized Ti-6Al-4V disks.
  
  
  CONCLUSIONS
  These in vivo and in vitro results comprehensively and consistently demonstrate that photofunctionalization increases the bioactivity of Ti-6Al-4V and improves the anchoring capability of orthodontic miniscrews.
authors.forename: Masako
authors.initials: M
authors.lastname: Tabuchi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ikeda
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirota
authors.forename: Kaori
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Wonhee
authors.initials: W
authors.lastname: Park
authors.forename: Ken
authors.initials: K
authors.lastname: Miyazawa
authors.forename: Shigemi
authors.initials: S
authors.lastname: Goto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis; D000497:Alloys; D000818:Animals; D001696:Biomechanical Phenomena; D001863:Bone Screws; D000069343:Bone-Implant Interface / Q000033:anatomy & histology; D002113:Calcification, Physiologic / Q000502:physiology; D002118:Calcium / Q000032:analysis; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D003722:Dental Alloys / Q000737:chemistry / Q000528:radiation effects*; D005269:Femur / Q000601:surgery / Q000648:ultrastructure; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D008422:Materials Testing; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016348:Osseointegration / Q000187:drug effects; D010006:Osteoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000502:physiology; D010758:Phosphorus / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000497:Alloys; D003722:Dental Alloys; C031462:titanium alloy (TiAl6V4); D010758:Phosphorus; D014025:Titanium; D000469:Alkaline Phosphatase; D002118:Calcium