| In this investigation 20 teeth with periapical lesions were treated. |
| Microorganisms and their products play a fundamental role in the pathogenesis of the pulp and periapical infections. |
| If the root canals were properly sealed, no negative reactions of the periapical tissue were observed. |
| Contact with periapical tissue may occur in the event of accidental overfilling. |
| Complete series of periapical and panoramic once every 24 months. |
| Root canal irrigation carries a risk of extrusion of irrigant into the periapical tissues. |
