Screw-type device diameter and orthodontic loading influence adjacent bone remodeling.
OBJECTIVE
To evaluate the effect of diameter and orthodontic loading of a screw-type implantable device on bone remodeling.


METHODS
Screw-shaped devices of four distinct diameters, 1.6, 2, 3, and 3.75 mm, were placed into edentulous sites in five skeletally mature beagle dogs (n = 14/dog) following premolar extraction. Using a split-mouth design, devices on one side were loaded using calibrated 2N coil springs. Epifluorescent bone labels were administered intravenous prior to sacrifice. Bone-implant sections (∼ 70 μm) were evaluated to quantify bone formation rate (BFR), and other histomorphometric variables were assessed in the implant supporting bone.


RESULTS
The mean BFR ranged from 10.93 percent per year to 38.91 percent per year. BFR in the bone adjacent to the device was lower for the loaded 1.6-mm screws when compared with the nonloaded 1.6-mm screws (P < .01) and the loaded 2.0-, 3.0-, and 3.75-mm diameter screws (P < .01). No significant differences in BFR were noted, regardless of loading condition, between the 2.0-, 3.0-, and 3.75-mm diameter screws.


CONCLUSIONS
We detected a dramatic reduction in bone remodeling. Although orthodontic loading of 2N did not alter bone remodeling associated with screws with a 2.0-mm diameter or larger, it did decrease bone remodeling adjacent to a loaded 1.6-mm screw. The long-term effect of this diminished remodeling should be further investigated.
Jonathan Christian
JC
Francis
Ulas
U
Oz
Larry L
LL
Cunningham
Pinar
P
Emecen Huja
Richard J
RJ
Kryscio
Sarandeep S
SS
Huja
D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D001863:Bone Screws; D003799:Dental Stress Analysis; D004285:Dogs; D008297:Male; D023421:Models, Animal; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D013499:Surface Properties; D013997:Time Factors
Beagle dogs; Bone remodeling; Mini screws; Orthodontic force