Influence of mini-screw diameter and loading conditions on static and dynamic assessments of bone-implant contact: An animal study

Cristina R. Exposto, Ulas Oz, Philip M. Westgate, Sarandeep S. Huja

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Objectives: The goal was to compare static versus dynamic bone-implant interface histology of mini-screws and to evaluate its relation to diameter and load. Setting and Sample Population: Canine animal model. Material and Methods: Custom-machined, titanium alloy (Ti6AI4V) mini-screws (n = 70) of 1.60, 2.00, 3.00 and 3.75 mm diameter were placed into edentulous sites in five skeletally mature beagle dogs. Using a split-mouth design, no load (NL) was applied to one side while a 2N load (L) was applied by calibrated coil springs on the other side. Intravenous bone labels were administered 21 and 7 days prior to sacrifice. Dogs were euthanized 90 days after screw placement. Bone sections were analysed under bright-field and epifluorescent light. The region of interest was defined as the bone within the threads of the screws. The following parameters were quantified: (a) Static—bone volume/tissue volume (BV/TV %) and bone-implant contact (BIC, %); (b) Dynamic—labelled bone/bone volume (LB/BV, %), and dynamic BIC (DBIC, %). Results: BV/TV ranged from 71.2% to 85.0% of the screw surface. BIC ranged from 45.7% to 55.4% of the screw surface and was not affected by diameter (P = 0.66). In contrast, the percentage of DBIC did not vary with the applied load (P = 0.41); however, it correlated significantly with the diameter of the screw (P = 0.001). Conclusion: The percentage of DBIC that is actively remodelling increases with increasing diameter of the screw. Dynamic histomorphometry is more sensitive to detecting changes in bone-implant contact when compared to static measurements.

Original languageEnglish
Pages (from-to)96-100
Number of pages5
JournalOrthodontics and Craniofacial Research
Issue numberS1
StatePublished - May 2019

Bibliographical note

Publisher Copyright:
© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd


  • bone histomorphometry
  • bone-implant contact
  • mini-implant
  • mini-screw

ASJC Scopus subject areas

  • Orthodontics
  • Surgery
  • Oral Surgery
  • Otorhinolaryngology


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