This study evaluated the histopathologic reactions of rat connective tissue to two glass-ionomer cements (Fuji Cap II, Fuji Ionomer Type III) and two microfilled light-cured composite resins (Helio-molar Radiopaque and Helioprogress). IRM (zinc oxide-eugenol cement) was used as a control. Discs of the materials, 5 mm in diameter and 2 mm thick, that had set for 15 minutes were implanted under the dorsal skin of 75 Sprague-Dawley rats. There were 15 rats in each group and each animal received two identical implants. Five rats from each group were terminated at 7, 28 and 85 days after implantation. Histologic sections of the implant sites were stained with hematoxylin and eosin. Findings at all study periods indicated that Fuji Ionomer Type III elicited more intense reactions than the other materials. Reactions to Fuji Cap II, Heliomolar Radiopaque and Helioprogress, at all study periods, were comparable to each other and to IRM.
