title: Histomorphometric analysis of overloading on palatal tooth movement into the maxillary sinus.
abstract: BACKGROUND
  Our objective was to evaluate the effect of overloading on the palatal movement of the maxillary molar.
  
  
  METHODS
  The maxillary first molars of male C57Bl/6 mice were moved palatally with loads of 10 or 30 g for 14 days, and the amount of tooth movement was longitudinally measured on microcomputed tomography images. Bone remodeling around the molar root with the 30-g load was evaluated at days 3, 5, 7, and 14 after the start of tooth movement using histomorphometry and immunodetection of bone-restricted interferon inducible transmembrane-like protein, a novel marker of active bone formation.
  
  
  RESULTS
  In the 10-g load group, the amount of tooth movement increased dramatically between days 5 and 7 and increased gradually thereafter. Tooth movement at days 5 and 7 was significantly lower in the 30-g-load group than in the 10-g load group; however, the total tooth movement at 14 days was similar in the 2 groups. An orthodontic load of 30 g stimulated bone formation on the sinus wall, but bone resorption on the periodontal ligament side was delayed because of hyalinization, which means that strong force application did not accelerate tooth movement. Moreover, some root resorption was induced by the excessive force.
  
  
  CONCLUSIONS
  Root penetration into the sinus and bone height reduction do not occur because new bone formation on the maxillary sinus is induced before bone resorption on the periodontal side, even though an excessive orthodontic force is applied. However, an excessive force can induce root resorption.
authors: Graduate student, Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences, Tokushima, Japan.
authors: Yuichi
authors: Y
authors: Maeda
authors: Associate professor, Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan. Electronic address: kuroda@tokushima-u.ac.jp.
authors: Shingo
authors: S
authors: Kuroda
authors: Graduate student, Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences, Tokushima, Japan.
authors: Khaliunaa
authors: K
authors: Ganzorig
authors: Research associate, Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montréal, Québec, Canada.
authors: Rima
authors: R
authors: Wazen
authors: Professor, Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montréal, Québec, Canada.
authors: Antonio
authors: A
authors: Nanci
authors: Professor and chair, Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan; distinguished adjunct professor, King Abdulaziz University, Jeddah, Saudi Arabia.
authors: Eiji
authors: E
authors: Tanaka
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology; D003722:Dental Alloys / Q000737:chemistry; D006818:Hyalin / Q000737:chemistry; D008297:Male; D008437:Maxilla / Q000473:pathology; D008443:Maxillary Sinus / Q000473:pathology; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D023421:Models, Animal; D008963:Molar / Q000473:pathology*; D009532:Nickel / Q000737:chemistry; D009969:Orthodontic Wires; D010006:Osteoblasts / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D010513:Periodontal Ligament / Q000473:pathology; D012391:Root Resorption / Q000209:etiology; D013314:Stress, Mechanical; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000295:instrumentation; D014092:Tooth Root / Q000473:pathology; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D003722:Dental Alloys; C532488:IFITM5 protein, mouse; D008565:Membrane Proteins; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium