Objectives:To evaluate the influence of local administration of pamidronate histomorphometrically, adsorbed on a collagenated porcine bone substitute, on extraction socket healing.

Material and methods:Two American Fox-hound dogs were used within this proof-of-principle study. Following endodontic treatment of the distal root of the three lower premolars, the teeth were hemisected, and the mesial roots were extracted flapless. The sockets were then loosely filled, in a split-mouth fashion, with a collagenated porcine bone substitute (Osteobiol Gen-Os; CPB), rehydrated either with 90mg/ml pamidronate (Aredia((R)); test) or with sterile saline (control). Extraction sockets were sealed with connective tissue punches obtained from the palate and secured with sutures. After 4months of healing, specimens containing the socket sites and remaining roots were retrieved and histomorphometrically examined.

Results:Histological evaluation of the sections revealed substantial differences in healing patterns. Control sites presented with various amounts of newly formed bone and no evidence of CPB inside the socket; in contrast, limited amounts of bone were observed at test sites, which were filled with CPB mainly embedded in connective tissue. Only minor differences were observed between test and control sites regarding vertical bone loss (buccal bone: -1.01mm vs. -1.15mm; lingual bone: -0.92mm vs. -1.15mm). Horizontal bone loss was nearly three times higher in control sites comparing to sites treated with pamidronate (-2.191.81mm vs. -0.80 +/- 0.91mm) at a level corresponding to 3mm below the cemento-enamel junction (CEJ).

Conclusion:Local administration of pamidronate adsorbed on a collagenated porcine bone substitute in particulate form appeared to delay extraction socket healing, but may also reduce post-extraction dimensional changes in terms of horizontal bone width. Additionally, pamidronate appears to obstruct resorption of the porcine bone substitute.