Background: There are three common gypsum product materials used to create dental molds and dies, which are dental plaster, dental stone, and improved stone. Improved stone is the best choice for making final molds and dies. Dental plaster is the cheapest option, but it demonstrates the lowest compressive strength. Because of these issues, dental plaster is mostly used for temporary molds and dies, not for the final ones. Objectives: The purpose of the study is to assess the compressive strength, wettability, setting time, and setting expansion of conventional type II dental gypsum that has been manually blended with 10 wt.% calcium bentonite clay/activated carbon fiber fillers. Methods: The conventional type II dental gypsum powder and water were mixed to create the control group; the modified group was made by mixing the conventional dental plaster powder with 10 wt.% bentonite-activated carbon and then mixing with water; the third group was created by mixing the improved stone powder and water. Data were analyzed using one-way ANOVA and Tukey tests (p < 0.05). Results: The findings showed that the modified dental plaster demonstrated a higher mean compressive strength and higher wettability than the other tested groups. While the conventional dental plaster showed the highest significant setting expansion, followed by conventional improved stone and modified dental plaster, with no significant difference between them. Moreover, there was no significant difference between the setting time of the three tested groups, either for the initial or the final setting time.

Conclusion: The modified dental plaster, by incorporating 10 wt.% bentonite-activated carbon fillers, could be used as an alternative to conventional improved stone.