Sometimes when we try locating canals during access preparation stage, we may accidentally exit the pulp chamber in the wrong spot and create perforations. Perforations or accidental communications need to be repaired as soon as possible in order to achieve the best possible prognosis. The choice of repair material depends on the location and the size of perforation. MTA is still one of the best materials that can be used to seal the pulp floor perforations as long as it is not communicating with the sulcus.
To Prevent Perforations:
1. The pulp chamber floor is always at or slightly below the level of CEJ and the canals are located at the periphery of the pulp chamber floor. Any attempt to locate canals farther apically may result in perforation.
2. The chamber floor colour is always greyish. If the colour during locating canals is turning dentin-colour, that would be the best time to stop and reorient ourselves.
3. Always probe around the CEJ to gain a better appreciation the outline of the root trunk, as the chamber floor is at the center and concentric to the CEJ outline.
4. When in doubt, stop and take an X-ray to confirm that treatment is progressing in the right direction.
To Treat Perforations:
1. If facing significant difficulty with locating canals, the procedure should be stopped, the tooth should be medicated with CaOH, and patient should be referred out for proper care. More digging may result in multiple perforation sites, further weakening of the tooth structure and enlargement of the existing perforation site, which ultimately results in an unfavorable outcome.
2. If canals are already located, ignore the perforation site, complete the root canal treatment and repair the perforation site with MTA. Attempting to repair the site before obturating the canals may result in the repair material occluding the shaped and cleaned canals.
3. When dealing with established infection in the canal system which benefits from the utilization of short term CaOH medicament, the perforation site can be repaired and sealed before final obturation. In this case, the other canals need to be protected by paper points while the site is being repaired (the above case).