The anchorage mechanisms currently used in orthodontic treatment have various disadvantages. The objective of this study was to determine the applicability of the
osteoporosis medication
strontium ranelate in pharmacologically induced orthodontic tooth anchorage. In 48 male Wistar rats, a constant orthodontic force of 0.25 N was reciprocally applied to the upper first molar and the incisors by means of a
Sentalloy(®) closed coil spring for two to four weeks. 50% of the animals received
strontium ranelate at a daily oral dosage
of 900 mg per kilogramme of
body weight. Bioavailability was determined by blood analyses. The extent of tooth movement was measured both optometrically and cephalometrically (CBCT). Relative alveolar gene expression of osteoclastic markers and OPG-RANKL was assessed by qRT-PCR and
root resorption area and osteoclastic activity were determined in TRAP-stained histologic sections of the alveolar process. Compared to controls, the animals treated with
strontium ranelate showed up to 40% less tooth movement after four weeks of orthodontic treatment. Gene expression and histologic analyses showed significantly less osteoclastic activity and a significantly smaller
root resorption area. Blood analyses confirmed sufficient bioavailability of
strontium ranelate. Because of its pharmacologic effects on bone metabolism,
strontium ranelate significantly reduced tooth movement and
root resorption in orthodontic treatment of rats.
Strontium ranelate may be a viable agent for inducing tooth anchorage and reducing undesired
root resorption in orthodontic treatment. Patients under medication of
strontium ranelate have to expect prolonged orthodontic treatment times.