Leaving the pulp chamber open for drainage has no effect on the complications of root canal therapy.

In this retrospective study the effects of different kinds of emergency treatments on flare-ups and other complications were examined. A total of 197 teeth received emergency treatment after diagnosis at the beginning of the root canal therapy; in 103 the pulp chamber was left open for drainage of pus, 35 were treated with dexamethasone sodium phosphate, and 59 with various other medicaments, followed by routine root canal treatment. In all, 404 teeth received root canal treatment without emergency treatment. If symptoms occurred during treatment, flare-up was said to be present. If a periapical radiolucency was found, long-term calcium hydroxide treatment was used: no sign of periapical healing radiographically after 6 months was described as a complication. The percentage of teeth with no complications varied from 72.2% (dexamethasone) to 78.9% (other modification) and the results showed no differences between the groups in the teeth with no complications, flare-ups or other complications. The number of bacteria detected with Gram's staining was higher in the teeth which were left open. In conclusion, leaving the pulp chamber open for drainage had no effect on the incidence of flare-ups or other complications.