Influence of powder-liquid ratio on the physicochemical properties of MTA Repair HP cement

Introduction: MTA Repair HP has been recently developed. The aim of this study was to evaluate setting time, radiopacity and solubility of HP Repair MTA in powder-liquid ratio according to manufacturer's instructions (MTA HP+, 0.8 g powder and liquid 320μl) or less powder (MTA HP- 0.7 g powder and liquid 320 μl) compared to MTA Angelus. Material and methods: The radiopacity was assessed by radiographs of materials in relation to an aluminum scale. Setting time was evaluated by Gilmore needles; and solubility, after immersing the material in distilled water (7 days). Data were analyzed by using ANOVA and Tukey tests with a 5% significance level. Results: The initial and final setting times were longer for MTA HP- than MTA HP+ and MTA Angelus (p < 0.05). MTA HP+ and MTA HP- had higher solubility than the MTA Angelus (p < 0.05). The radiopacity values of MTA HP+ and MTA HP- were lower than the MTA Angelus (p < 0.05). Conclusions: Decreasing the amount of powder in powder-liquid ratio of MTA HP results in longer setting time, with no change in other properties evaluated. MTA HP had lower radiopacity than MTA Angelus.