A preform intended for the production of a dental prosthesis. The preform includes a group of agglomerated ceramic, glass-ceramic or glass particles, such that, as volume percents: more than 40% and less than 90% of the particles of said group have a size greater than 0.5 μm and less than 3,5 μm, said particles hereinafter being denoted “enamel particles”, and more than 10% and less than 60% of the particles of said group have a size greater than 3.5 μm and less than 5.5 μm, said particles hereinafter being denoted “dentine particles.” The microstructure of the preform is such that there is an axis X, termed “axis of variation”, along which the Ve/(Ve+Vd) ratio changes continuously, Ve and Vd denoting the volume percents of enamel particles and of dentine particles, respectively. The enamel and dentine particles representing, together, more than 90% of the volume of the agglomerated particles.
