Repair processes in the periodontium following dentoalveolar ankylosis: the effect of masticatory function
Recent study has shown that administration of the drug 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) disturbs the homeostasis in the periodontal ligament resulting in osteoid-medicated ankylosis between the alveolar wall and the root surface. The present investigation was to examine the events that take place after the discontinuation of HEBP administration. In 28 female mice, the maxillary left molars were extracted. A daily subcutaneous injection of HEBP in Ringer's solution at a dose of 10 mg phosphorous (p)/kg body weight was given to all animals for 50 days. Mice were killed 24 hours and 14, 28, 56, and 112 days after the last injection and their mandibles processed for light microscopy. HEBP administration caused a significant decrease of the width of the periodontal ligament space with localized ankylosis. Following discontinuation of HEBP administration, the osteoid mineralized and was then partly resorbed. Root resorption was also seen and can be induced without prior physical damage to the periodontal ligament. Functional teeth showed more root resorption than hypofunctional ones. It is suggested that after HEBP treatment the periodontal ligament regains its normal width by a repair process including extensive root resorption. [S.L.]
Wesselink, P.R., and W. Beertsen, J Clin Periodont, 21:472, 1994