2.2. Dentin permeability

Permeability was quantified using the split-chamber hydraulic conductivity system (THD-02b apparatus, Odeme Ltda, Brazil) reported by Pashley et al. [31] (Figure 1b). Initial hydraulic conductance (Lpini) was defined by calculating the mean flow/min as previously described [32, 33, 34]. After defining the Lpini, the exposed dentin from each specimen was treated with 0.3% citric acid for 30 s to remove the smear layer and simulate surfaces with patent dentinal tubules [31]. This permeability measurement was taken to be the maximum hydraulic conductance (Lpmax). Each specimen was then sonicated in ultrapure water for 10 min prior to further experiments.