Objective: Study the diametral tensile strength three type IV gypsum and mineral reinforced by plastic.
Method: Ten arrays of carbon steel 20mm in height X 10mm in diameter were fabricated and reproduced in industrial silicone. The molds were cast with the four types of gypsum in the study. All casts were handled on a vacuum machine according to the manufacturer's guidelines and stored for seven days in a wet chamber at the Laboratory of Applied Biotechnology – LABA of the Universidade Federal Fluminense - UFF. The samples were divided into four groups of 10: G1- GC Fugirock EP ( Europe); G2-Herostone (Vigodent); G3- Durone (Dentsply) and G4 - Rutenium Plastic (Cristobalita Ltda). ). Hereafter, diametral tensile tests were conducted on a universal testing machine (EMIC DL 2000), at the Laboratory of Theoretical and Applied Mechanics – LMTA of UFF, using a loading speed of 0.1 mm / min, to compression until failure occurs.
Results: The average values of RTD MPa groups were : G1- 0,99 (±4,74); G2- 1,35 (±0,21); G3- 1,09 (±0.12) and G4- 0,50 (±0.08). Data were submitted to ANOVA test showed a significant difference between the average of four groups (p<0.05). The Tukey test showed that only G4 presented statistically diference compared to the other groups.
Conclusion: It can be concluded that Rutenium Plastic presented less diametral tensile strength.