title: Optical approach to the periodontal ligament under orthodontic tooth movement: a preliminary study with optical coherence tomography.
abstract: BACKGROUND
  Optical coherence tomography (OCT) is a diagnostic tool that can make near-histologic tomographic images without a biohazard. Due to its high resolution (average, 4 microm) and safety (using light as the source), it has been applied widely in medical fields to replace invasive biopsies. But the trials in dentistry have been restricted to mainly detecting dental caries and oral cancer. In this preliminary study for successive human studies, we tried to evaluate whether OCT can be helpful in determining tooth movement under light orthodontic forces.
  
  
  METHODS
  Orthodontic distraction forces (0, 5, and 10 g) were applied to the mandibular incisors of 6 white rats (10 weeks old) for 5 days by using individualized loop springs (round Elgiloy, 0.018-in diameter, Rocky Mountain Orthodontics, Denver, Colo). The changed periodontal ligaments were imaged with OCT and digital intraoral radiography 2 dimensionally. Both tensile and compressive ligaments were measured and compared.
  
  
  RESULTS
  With OCT images, we could measure changed ligaments from all directions; radiography could not show the portions overlapped by teeth. The averages of measured ligament width in OCT were larger than those from radiography in all groups.
  
  
  CONCLUSIONS
  This preliminary study shows the possible evaluation and prediction of precise tooth responses under orthodontic forces by using real-time OCT.
authors.affiliation: Department of Orthodontics, Division of Dentistry, Ulsan University Hospital, Ulsan, South Korea. baek@baekorthodontics.com
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Baek
authors.forename: Jihoon
authors.initials: J
authors.lastname: Na
authors.forename: Byeong Ha
authors.initials: BH
authors.lastname: Lee
authors.forename: EunSeo
authors.initials: E
authors.lastname: Choi
authors.forename: Woo Sung
authors.initials: WS
authors.lastname: Son
mesh_terms: D000539:Alveolar Process / Q000473:pathology; D000818:Animals; D001696:Biomechanical Phenomena; D005240:Feasibility Studies; D007180:Incisor / Q000473:pathology; D008297:Male; D009969:Orthodontic Wires; D010513:Periodontal Ligament / Q000473:pathology*; D019252:Radiography, Dental, Digital; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D041623:Tomography, Optical Coherence / Q000379:methods*; D014087:Tooth Movement Techniques / Q000295:instrumentation