ANCHORAGE AND RETENTIVE EFFECTS OF A BISPHOSPHONATE (AHBUBP) ON TOOTHMOVEMENTS IN RATS

The purpose of this study was to examine the effect of 4-amino-1-hydro xybutylidene-1,1-bisphosphonate (AHBuBP), a potent blocker of bone res orption, on orthodontic tooth movements in rats. In the first experime nt, the right and left upper first molars were moved buccally for 3 we eks with a uniform standardized expansion spring under systemic admini stration of AHBuBP every other day. The total tooth movement during th e 3-week experimental period was 40% of that in the control at a dose of 0.5 mg P/kg. In the second experiment, the right and left upper fir st molars were first moved buccally for 3 weeks without AHBuBP. The sp ring was then removed and administration of AHBuBP was initiated. The total relapse movement during the 3-week experimental period was 50% o f that in the control at a dose of 0.5 mg P/kg. Results of the first a nd second experiments were both dose dependent. Histologic examination showed that in the experimental animals fewer osteoclasts appeared on the alveolar bone surface, and both bone resorption and root resorpti on were inhibited. Inhibition of tooth movement was also observed when AHBuBP was applied topically. These results suggest that AHBuBP could be useful in enhancing anchorage or retaining teeth in orthodontic tr eatment.