title: The impact of healing time before loading on orthodontic mini-implant stability: a histomorphometric study in minipigs.
abstract: OBJECTIVE
  To evaluate healing time before loading, areas compression and tension and location of insertion on mini-implant stability.
  
  
  METHODS
  Six minipigs were used. Each animal received 3 mini-implants in each quadrant: 1 mini-implant was used as an unloaded control (G1, n=24); the other 2 were loaded with 150g-force at three time intervals (G2: immediate loading, G3: after 15 days and G4: after 30 days), with 16 mini-implant in each experimental group. After 120 days, tissue blocks of the areas of interest were harvested. Clinical analysis (exact Fisher test) determined the survival rate. Histological analysis (Kontron KS 300™, Zeiss) quantified the fractional bone-to-implant contact (%BIC) and bone area (%BA) at each healing time point, areas of interest, and insertion site (ANOVA and t tests for dependent and independent samples).
  
  
  RESULTS
  The mini-implant survival rates were G1: 71%, G2: 50%, G3: 75% and G4: 63%, with no statistical differences between them. The groups presented similar %BIC and %BA. There were no differences between the compression and tension sides or maxillary and mandibular insertion sites.
  
  
  CONCLUSIONS
  These results suggest that low-intensity immediate or early orthodontic loading does not affect mini-implant stability, because similar histomorphometric results were observed for all the groups, with partial osseointegration of the mini-implants present.
authors: University of North Parana, Londrina, PR, Brazil. pvoltramari@hotmail.com
authors: Paula V P
authors: PV
authors: Oltramari-Navarro
authors: Ricardo L
authors: RL
authors: Navarro
authors: José Fernando C
authors: JF
authors: Henriques
authors: Tânia M
authors: TM
authors: Cestari
authors: Carlos E
authors: CE
authors: Francischone
authors: Rumio
authors: R
authors: Taga
authors: James A
authors: JA
authors: McNamara
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015921:Dental Implants; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D008334:Mandible / Q000473:pathology* / Q000502:physiology; D008437:Maxilla / Q000473:pathology* / Q000502:physiology; D016348:Osseointegration / Q000502:physiology*; D010784:Photomicrography; D013552:Swine; D013556:Swine, Miniature; D014945:Wound Healing
chemical_list: D015921:Dental Implants