The purpose of the current study was to improve the mechanical strength and reduce the micro-cracks on the microstructure of the dentin ceramic through addition of various boron compounds (borax, boric acid). Following addition of borax and boric acid (1, 2, 3% of the weight percent) to the traditional feldspathic porcelain; crack lengths, flexural strength and fracture toughness were analyzed. The data analyses were performed by using one-way ANOVA (p<0.05). Differences between groups were determined by Tukey HSD. The results of the present study suggested that the crack lengths were decreased and the fracture toughness were increased in all boric acid added groups (p<0.05). The group containing 1% boric acid had significantly decreased the biaxial flexural strength value compared to the control group (p<0.05). The Vicker’s hardness value of the group containing 1% borax was found to be significantly lower (p<0.05). The present study demonstrated that various proportions of borax and boric acid addition in dentin ceramic had reduced the formation of cracks. The current study could be a good starting point on reinforcement of dental ceramics with a possible outcome that will reduce the failures of dental restorations.

Keywords: boric acid, borax, feldspathic ceramic, mechanical features