title: Effect of corticision and different force magnitudes on orthodontic tooth movement in a rat model.
abstract: BACKGROUND
  The aims of this study were to evaluate the effect of 2 distinct magnitudes of applied force with and without corticision (flapless corticotomy) on the rate of tooth movement and to examine the alveolar response in a rat model.
  
  
  METHODS
  A total of 44 male rats (6 weeks old) were equally divided into 4 experimental groups based on force level and surgical intervention: light force, light force with corticision, heavy force, and heavy force with corticision. The forces were delivered from the maxillary left first molar to the maxillary incisors using prefabricated 10-g (light force) or 100-g (heavy force) nickel-titanium springs. The corticision procedure was performed at appliance placement and repeated 1 week later on the mesiopalatal aspect of the maxillary left first molars, with the right sides serving as the untreated controls. Microcomputed tomography was used to evaluate tooth movement between the maxillary first and second molars, and the alveolar response in the region of the maxillary first molar on day 14. Osteoclasts and odontoclasts were quantified, and the expression of receptor activator of nuclear factor kappa ß ligand was examined.
  
  
  RESULTS
  Intragroup comparisons of bone volume fraction (BVF) and tissue density were found to be significantly less on the loaded sides, with the exception of BVF in the light force group. Intergroup comparisons evaluating magnitude of tooth movement, BVF, apparent density, and tissue density showed no significant differences. Histomorphometric analysis indicated that BVF was decreased in the light force group. No significant differences in the total numbers of osteoclasts and odontoclasts and the expression of receptor activator of nuclear factor kappa ß ligand were found between the groups.
  
  
  CONCLUSIONS
  No differences in tooth movement or alveolar response were observed with microcomputed tomography based on force level or corticision procedure. A flapless surgical insult in the mesiopalatal aspect of the first molar with a single-site corticision was unable to induce clinical or histologic changes after 2 weeks of orthodontic tooth movement regardless of the force magnitude. Histologic analysis of the furcation area showed that light force significantly decreased BVF.
authors: Private practice, Madison, Conn.
authors: Christopher A
authors: CA
authors: Murphy
authors: Assistant professor, Division of Orthodontics, Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut, Farmington, Conn.
authors: Taranpreet
authors: T
authors: Chandhoke
authors: Research associate, Division of Orthodontics, Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut, Farmington, Conn.
authors: Zana
authors: Z
authors: Kalajzic
authors: Undergraduate dental student, School of Dental Medicine, University of Connecticut, Farmington, Conn.
authors: Rita
authors: R
authors: Flynn
authors: Resident, Division of Orthodontics, Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut, Farmington, Conn.
authors: Achint
authors: A
authors: Utreja
authors: Assistant professor, Division of Orthodontics, College of Dental Medicine, Columbia University, New York, NY.
authors: Sunil
authors: S
authors: Wadhwa
authors: Professor and head, Division of Orthodontics, Department of Craniofacial Sciences; alumni endowed chair, School of Dental Medicine, University of Connecticut, Farmington, Conn.
authors: Ravindra
authors: R
authors: Nanda
authors: Associate professor and program director, Division of Orthodontics, Department of Craniofacial Sciences; Charles Burstone professor, School of Dental Medicine, University of Connecticut, Farmington, Conn. Electronic address: Furibe@uchc.edu.
authors: Flavio
authors: F
authors: Uribe
mesh_terms: D000539:Alveolar Process / Q000473:pathology / Q000601:surgery; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D016723:Bone Remodeling / Q000502:physiology; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000473:pathology; D008297:Male; D008437:Maxilla / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D008963:Molar / Q000473:pathology; D009969:Orthodontic Wires; D010010:Osteoclasts / Q000473:pathology; D010027:Osteotomy / Q000379:methods*; D053245:RANK Ligand / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*; D014092:Tooth Root / Q000473:pathology; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D053245:RANK Ligand