Biocompatibility of an experimental glass-ionomer cement sealer in rat mandibular bone

Objective. The purpose of this study was to compare an experimental glass-ionomer cement sealer, KT-308, with a conventional zinc oxide-eugenol sealer, Canals, in terms of tissue compatibility and solubility. Study design. Tissue reactions were examined under light and electron microscopes at 3 and 20 days after the implantation of either freshly mixed KT-308 sealer or Canals sealer into prepared cavities in rat mandibles. Results. At 3 days after implantation, no inflammatory reaction was seen around KT-308 sealer, which was in direct contact with the bone surface. In contrast, Canals sealer elicited an initially severe inflammation in the surrounding tissue. At 20 days, the majority of KT-308 sealer remained in the bone cavity. Canals sealer was largely absorbed and surrounded by fibrous tissue with many macrophages. An ultrastructural examination also revealed that no intervening tissue was present between the cut bone surface and the glass-ionomer cement sealer and that disintegrated zinc oxide-eugenol particles were engulfed by macrophages. Conclusions. KT-308 sealer possesses better tissue compatibility and lower solubility compared with a conventional zinc oxide-eugenol sealer, suggesting its potential for use as a root canal sealant.