In an embodiment, a polycrystalline diamond compact includes a substrate and a preformed polycrystalline diamond table bonded to the substrate. The table includes bonded diamond grains defining interstitial regions. The table includes an upper surface, a back surface bonded to the substrate, and at least one lateral surface extending therebetween. The table includes a first region extending inwardly from the upper surface and the lateral surface. The first region exhibits a first interstitial region concentration and includes at least one interstitial constituent disposed therein, which may be present in at least a residual amount and includes at least one metal carbonate and/or at least one metal oxide. The table includes a second bonding region adjacent to the substrate that extends inwardly from the back surface. The second bonding region exhibits a second interstitial region concentration that is greater than the first interstitial region concentration and includes a metallic infiltrant therein.