(PR40) Pulp Dissolving Capacity of Trichloroacetic Acid Compared to NaOCl

Objective: To determine the tissue dissolution capacity of trichloroacetic acid (TCA) and in combination with NaOCl.

Methods: Pulp tissue was collected from freshly extracted human teeth and cut into ~10 mg fragments. The weight of each fragment was measured before and after soaking in 100 µL solution either 90% TCA and/or 6% NaOCl in a tube. Pulp tissue in the solution was incubated at the room temperature (RT) under a static condition or at 37^oC in an incubator rotating at 700 rpm. The following treatment groups were tested: NaOCl, TCA, TCA 1 min then NaOCl, TCA + NaOCl. After 1, 3, 5 min, the solution was pipetted out from the tube and the remaining tissue weighed. Two-way ANOVA was used.

Results: Under static condition (RT) NaOCl dissolved ~70% of pulp within one minute without further loss at five minutes. TCA dissolved ~48-55% with increasing loss reaching five minutes, which was significantly different from NaOCl (p <.05). TCA first then NaOCl caused ~65% loss throughout. TCA+NaOCl dissolved pulp overtime from 54.2% to 78.0% (p < 0.05). Under agitated condition (37^oC), NaOCl dissolved pulp from one minute at 72.2% to 94.6% at three minutes (p <.05); TCA ~65% (one minute: 64%, three minutes: 68.7%); TCA+NaOCl was similar to TCA alone (62.2%, 66.4% respective to one and three minutes) and was significantly less than NaOCl alone (p < 0.05).

Conclusion: TCA breaks down pulp tissue but less than NaOCl. Further investigation is needed to determine the biological effect of TCA on pulp during endodontic treatment.