Calcium hydroxide is a widely used material in endodontic treatment due to its high alkalinity and antimicrobial properties. It is thought to create a favourable environment for periradicular repair and healing, and to stimulate hard tissue formation. The aim of the present retrospective study was to evaluate the effect of accidental and voluminous overextensions of calcium hydroxide pastes into periapical lesions and tissues on the prognosis of periapical healing. It was seen that calcium hydroxide overextensions did not disfavour healing, none of the endodontic treatments failed but healing was delayed in the majority of cases and in a number of cases extrusion induced immediate flare-ups. Therefore the deliberate extrusion of calcium hydroxide into periapical tissues is not advocated.