This work compared the tensile strength of two glass compositions with published values of currently available dental porcelains. The influence of several variables, such as air and vacuum firing, firing temperature, surface roughness, immersion in water, and the inclusion of filler particles, on the inherent strength of the glass compositions is also discussed. The authors developed a glass frit having a tensile strength of 102.4 MPa as determined by the biaxial flexure technique. This value compares favorably with the reported strength of commercial brands of feldspathic porcelains. The strength of this glass was not significantly reduced as a result of surface abrasion or immersion in distilled water.