The invention relates to a porous preform for the production of a dental prosthesis, said preform comprising a group of agglomerated ceramic, glass-ceramic or glass particles, such that (expressed as volume percent): more than 40% and less than 90% of the particles of the aforementioned group have a size greater than 0.5 µm and less than 3.5 µm, said particles being hereafter referred to as "enamel particles"； and more than 10% and less than 60% of the particles of the group have a size greater than 3.5 µm and less than 5.5 µm, said particles being hereafter referred to as "dentin particles", the Ve/(Ve+Vd) ratio of the volume percent Ve of enamel particles to the volume percent Vd of dentin particles changing continuously along an axis X, known as the "axis of variation".
