title: Sequential bone healing of immediately loaded mini-implants: histomorphometric and fluorescence analysis.
abstract: BACKGROUND
  Mini-implants are often immediately loaded for orthodontic treatment; however, changes in interfacial tissues caused by early loading and its effects might compromise the mini-implant's function. The purpose of this study was to compare the healing of interfacial tissues 1, 4, and 12 weeks after the placement of titanium-alloy mini-implants in New Zealand rabbits; some of the implants were loaded immediately and others were left unloaded.
  
  
  METHODS
  Eighteen animals were used in the experiment. Each received 4 titanium grade 5 mini-implants (2.0 x 6.0 mm), 2 of which were immediately loaded with 1 N of force. Tissue healing was verified at 1, 4, and 12 weeks after placement. Four different fluorescent molecules were injected into the rabbits to label calcium deposition. After the rabbits were killed, mineralized bone samples with the mini-implants were removed, fixed, cut, stained, and observed with bright-field, polarized, and fluorescence microscopy.
  
  
  RESULTS
  After 12 weeks of healing, higher bone contact and bone area were observed than after 1 or 4 weeks, regardless of loading. Differences between the loaded and unloaded groups were not observed (P <0.05) at 1 and 4 weeks. The bone deposition rate was higher in the loaded group.
  
  
  CONCLUSIONS
  The 1-N immediate force application did not compromise bone formation around mini-implants.
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California-San Diego, USA. gserrag@hotmail.com
authors.forename: Glaucio
authors.initials: G
authors.lastname: Serra
authors.forename: Liliane S
authors.initials: LS
authors.lastname: Morais
authors.forename: Carlos Nelson
authors.initials: CN
authors.lastname: Elias
authors.forename: Marc A
authors.initials: MA
authors.lastname: Meyers
authors.forename: Leonardo
authors.initials: L
authors.lastname: Andrade
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Müller
authors.forename: Marcelo
authors.initials: M
authors.lastname: Müller
mesh_terms: D000497:Alloys; D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology; D003722:Dental Alloys; D015921:Dental Implants; D003799:Dental Stress Analysis; D005456:Fluorescent Dyes; D020007:Implants, Experimental; D008297:Male; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D009967:Orthodontic Appliances; D016348:Osseointegration / Q000502:physiology*; D011817:Rabbits; D013977:Tibia / Q000601:surgery; D014025:Titanium; D014945:Wound Healing / Q000502:physiology*
chemical_list: D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; D005456:Fluorescent Dyes; C031462:titanium alloy (TiAl6V4); D014025:Titanium