A method of forming a three-dimensional object is carried out by: providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; filling the build region with a polymerizable liquid; irradiating the build region through the optically transparent member to form a solid polymer from the polymerizable liquid while concurrently advancing the carrier away from the build surface to form the three-dimensional object from the solid polymer, while also concurrently: (i) continuously maintaining a dead zone of polymerizable liquid in contact with the build surface by electrochemically generating a polymerization inhibitor therein from a precursor of the polymerization inhibitor, and (ii) continuously maintaining a gradient of polymerization zone (e.g., an active surface) between the dead zone and the solid polymer and in contact with each thereof, the gradient of polymerization zone comprising the polymerizable liquid in partially cured form. Apparatus for carrying out the method is also described.