Impact of bisphosphonate drug burden in alveolar bone during orthodontic tooth movement in a rat model: a pilot study.
BACKGROUND
The aim of this pilot study was to investigate the effect of long-term bisphosphonate drug use (bone burden) on orthodontic tooth movement in a rat model.


METHODS
Sprague Dawley rats were used for orthodontic protraction of the maxillary first molars with nickel-titanium coil springs and temporary anchorage devices as anchorage. Four groups of 5 rats each were included in the study; the first 2 groups were dosed with alendronate or a vehicle during concurrent orthodontic tooth movement. The third and fourth groups were pretreated for 3 months with alendronate or vehicle injections, and bisphosphonate drug treatment was discontinued before orthodontic tooth movement. Tooth movement measurements were obtained at 0, 4, and 8 weeks using high-resolution in-vivo microcomputed tomography, and the tissues were analyzed with histology and dynamic labeling of bone turnover.


RESULTS
Appreciable tooth movement was achieved during the 8-week duration of this study with nickel-titanium coil springs and temporary anchorage devices. Both bisphosphonate treatment groups exhibited reduced tooth movement compared with the vehicle-dosed controls with a tendency toward more severe reduction in the bisphosphonate predosed group. Concurrent dosing of the bisphosphonate drug resulted in 56% and 65% reductions in tooth protraction at the 4-week and 8-week times, respectively. The impact of bisphosphonate bone burden in retarding tooth movement was even greater, with 77% and 86% reductions in tooth movement at 4 and 8 weeks, respectively.


CONCLUSIONS
In this study, we used a robust rat model of orthodontic tooth movement with temporary anchorage devices. It has provided evidence that the bone burden of previous bisphosphonate use will significantly inhibit orthodontic tooth movement.
PhD candidate, Division of Orthodontics, Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
Neelambar R
NR
Kaipatur
Yuchin
Y
Wu
Samer
S
Adeeb
Thomas R
TR
Stevenson
Paul W
PW
Major
Michael R
MR
Doschak
D019386:Alendronate / Q000494:pharmacology*; D000539:Alveolar Process / Q000187:drug effects*; D000818:Animals; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D016723:Bone Remodeling / Q000187:drug effects*; D005260:Female; D008963:Molar / Q000000981:diagnostic imaging / Q000502:physiology; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation; D010865:Pilot Projects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014087:Tooth Movement Techniques; D055114:X-Ray Microtomography
D050071:Bone Density Conservation Agents; D019386:Alendronate