Preceramic silicone polymers are considered precursors for silicate bioactive ceramics, and feedstocks for additive manufacturing technologies. The current research regards the fabrication of wollastonite-diopside glass-ceramic scaffolds, using masked stereolithography, in which the final phase assemblage relies on the chemical interaction, upon firing, of softened glass consisting of ‘silica-defective glass’ specifically designed to react, with the amorphous silica yielded by the silicone binder. In particular, the sintering step in the production of glass-ceramics components can be problematic because viscous flow sintering is not always controllable depending on the glass composition, causing sometimes a complete loss of shape consequently. Surface crystallization is known to hinder the viscous flow, and thereby decreasing particle size distribution could control the sintering process. Nevertheless, this approach would be quite complex to accomplish because particle size distribution, in addition to the sintering heating rate, has to be carefully tuned to achieve full densification. In contrast to this, the employment of preceramic polymers can easily solve this issue. The SiO2 residue that yields after firing, works as a rigid backbone of the green body, and can help to control the viscous flow sintering and shape retention after densification.