title: The osseointegration stimulatory effect of macrogeometry-modified implants: a study in the rabbit.
abstract: OBJECTIVE
  To investigate the bone stimulatory effect of compression forces through histomorphometric analyses of macrothreaded implants with microthreads in between.
  
  
  METHODS
  Two sets of turned implants with different macrogeometries were prepared. The test group possessed microthreads in between macrothreads, and the control group had macrothreads only. The two-implant groups were placed in both the femur and the tibiae of 10 rabbits. After 4 weeks, the animals were sacrificed and were subjected to histologic processing and histomorphometry. On the prepared stained sections, the total bone area (BA), new BA and bone-to-implant (BIC) were calculated.
  
  
  RESULTS
  The mean new BA% (SD) for the test group in the femur presented significantly higher values compared with the control group, being 32.84 (32.5) ± 6.04 and 27.31 (28.19) ± 5.66, respectively (P = 0.04). There were no differences for the new BA in the tibia or the total BA% for both bone types (P = 0.86, P = 0.131, and P = 0.131, respectively). The mean BIC% (SD) in the femur was 13.66 (11.49) ± 6.86 for the test group and 8.48 (7.92) ± 3.31 for the control group and in the tibia, 11.4 (11.88) ± 4.21 for the test group and 13.91 (12.06) ± 6.07 for the control group, respectively. There was no statistical significance among the groups tested.
  
  
  CONCLUSIONS
  The modified implant macrogeometry with microthreads in between promoted effect in the femur. However, no statistical differences could be seen in the tibia, suggesting that the modification may be more effective in bone with poor bone quality, such as in the maxillary bone.
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Chowdhary
authors.forename: R
authors.initials: R
authors.lastname: Jimbo
authors.forename: C S
authors.initials: CS
authors.lastname: Thomsen
authors.forename: L
authors.initials: L
authors.lastname: Carlsson
authors.forename: A
authors.initials: A
authors.lastname: Wennerberg
mesh_terms: D000818:Animals; D015921:Dental Implants; D017267:Dental Prosthesis Design; D005269:Femur / Q000601:surgery; D020007:Implants, Experimental; D016348:Osseointegration; D011817:Rabbits; D013499:Surface Properties; D013977:Tibia / Q000601:surgery; D014025:Titanium
chemical_list: D015921:Dental Implants; D014025:Titanium
keywords: histomorphometric analysis; implant geometry alterations; macrothread; microthread