pH changes in radicular dentine associated with calcium hydroxide and corticosteroid/antibiotic pastes

The aim was to compare hydroxyl ion diffusion through dentine following placement of calcium hydroxide and Ledermix paste. Thirty-six teeth were divided into one control (n = 6) and three experimental (n = 10) groups - (i) Pulpdent paste; (ii) Pulpdent/Ledermix pastes; (iii) Ledermix paste and (iv) Saline. pH was measured in inner and outer dentine cavities over 12 months. Inner dentine time to maximum pH (T_max ) was 1 week for Pulpdent and 2 weeks for Pulpdent/Ledermix. Pulpdent's outer dentine T_max was 4 weeks and Pulpdent/Ledermix was 10 weeks. After day 1, Pulpdent pH was higher and this continued for 12 months. Pulpdent's outer dentine pH was higher than Ledermix and controls, but not significantly different from Pulpdent/Ledermix. Pulpdent/Ledermix had significantly higher pH than controls and Ledermix from day 5 until 10 months when Pulpdent/Ledermix outer dentine pH decreased and became similar. In all groups, pH reduced after 3 months.