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Influence of mini‐screw diameter and loading conditions on static and dynamic assessments of bone‐implant contact: An animal study
Author(s) -
Exposto Cristina R.,
Oz Ulas,
Westgate Philip M.,
Huja Sarandeep S.
Publication year - 2019
Publication title -
orthodontics and craniofacial research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 55
eISSN - 1601-6343
pISSN - 1601-6335
DOI - 10.1111/ocr.12293
Subject(s) - beagle , materials science , implant , biomedical engineering , dentistry , animal study , medicine , surgery
Structured Abstract 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 (Ti6 AI 4V) 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.