Effect of topical alendronate on root resorption of dried replanted dog teeth

Alendronate (ALN) is a third generation bisphosphonate with demonstrated os teoclast inhibitory activity that may slow down the resorptive process afte r severe traumatic injuries. Eighty-two premolar roots of five mongrel dogs were endodontically treated and restored, extracted and treated as follows : 70 roots were bench dried for either 40 or 60 min. Thirty-eight of these roots were then soaked for 5 min in a 1 mM solution of ALN in Hanks' Balanc ed Salt Solution (HBSS) and replanted. Thirty-two roots were soaked for 5 m in in HBSS and replanted. In the remaining 12 roots which were not exposed to the bench drying procedure, a 0.5 mM deep lingual mid-root cemental defe ct was made. Six of these roots were soaked in a 1 mM solution of ALIN in H BSS for 5 min and replanted. The other six roots were soaked for 5 min in H BSS and replanted. Historical negative and positive controls were used from similarly treated teeth in our previous studies. After 4 months the dogs w ere killed and the roots prepared for histological evaluation. Five-firn-th ick cross-sections of the root and surrounding tissue taken every 70 tm wer e evaluated for healing according to the criteria of Andreasen. In the 12 r oots with cemental defects, healing with cementum of the damaged root surfa ce was evaluated. In addition, residual root mass was also measured to dete rmine the extent of root structure loss for each soaking method. Cemental h ealing took place in all 12 artificially damaged roots, indicating that the se soaking media did not inhibit cementogenesis. The alendronate-soaked roo ts had statistically significantly more healing than the roots soaked in HB SS without alendronate. This improvement in healing was seen in all dogs ex cept one and in all teeth except the first premolar. Soaking in alendronate also resulted in significantly less loss in root mass due to resorption co mpared to those teeth soaked in HBSS without alendronate.