The process of engulfment of overextended root canal filling materials
was investigated in rat peritoneal macrophages in vitro. Root canal f
illing materials tested were Finapec APC, Sealapex, Canals-N, and Cana
ls, The phagocytosis rate of macrophages for the Finapec APC was signi
ficantly (p < 0.05) higher than that for other three root canal fillin
g materials, That for Canals was the lowest, About 95% of the cells ex
posed to Finapec APC were viable at 60 and 120 min, For Canals the per
centage was 74% and 63% at 60 and 120 min, respectively, Ruffle format
ion in macrophages was observed by scanning electron microscopy after
exposure to Finapec APC for 60 or 120 min, Many vacuoles were observed
in macrophages exposed to Canals for 60 min. It was concluded that th
e phagocytic rate of macrophages for Canals that showed a strong cytot
oxicity was lowest acid that the rate for Finapec APC that showed a lo
w cytotoxicity was the highest.