Introduction: the aim of the present study was to evaluate the influence of Propylene Glycol (PG) on the flowability, microhardness, pH and calcium ion release of calcium-enriched mixture (CEM). Methods and Materials: CEM cement was mixed with different proportions of PG, as follows: group 1, 100% CEM liquid (CL); group 2, 100% PG; group 3, 50% PG and group 4, 20% PG. For assessment of flowability, methodology of ADA Specification No. 57 was applied. For measuring microhardness, 80 cylindrical molds (6×4 mm) were filled with CEM cement and divided into 2 subgroups (4, 21 days) and tested using Vickers Test. Data were analyzed using the one-way ANOVA test and Tukey’ s post hoc and student’ s t test. In order to check pH and calcium release, the mixed cements were placed in cylindrical molds (5×2 mm). After 3, 24, 72 and 168 h, pH determined by a pH meter and the calcium release was measured by an atomic absorption spectrophotometer. Data were analyzed using the repeated measure ANOVA, one way ANOVA test and Tuckey’ s post hoc test. Results: The present study showed that the presence of PG did not affect the flowability. With the elapse of time, microhardness was significantly increased in all groups except CL group. Regardless of time, samples with 50% PG showed the lowest pH value which was significantly different from other groups (P<0. 05) and samples with 100% and 20% PG showed significantly higher calcium ion release compared to other group. Conclusion: addition of PG did not have any positive or negative effect on the flowability and pH of CEM cement but increased its microhardness in long term. Calcium ion release also increased in the concentration of 20% and 100%.

Introduction: This study aimed to evaluate the efficacy of a synthesized bolus in the reduction of damage to body tissues and the protection of the organ at risk (OAR) in radiotherapy application. Several properties of the synthesized bolus, including density, transmission factor, and effective mass attenuation coefficient, were investigated. Material and Methods: The materials used comprising of Propylene Glycol (PG), silicone rubber (SR), and aluminum (Al). The dimension of the synthesized bolus was measured using an acrylic case with a size of 11×11 cm² and thickness sizes of 0. 5, 1, and 1. 5 cm. Furthermore, the boluses were irradiated by linear accelerator with the photon beam energies of 6 and 10 MV, using linier accelerator (LINAC) Varian 2300ix. Results: In this research, the density of synthesized bolus was evaluated by mass per volume equation. The results showed that the density of bolus was similar to the density of tissue/water, fat, and air. . Furthermore the bolus with the composition of PG 24%, SR 8%, and Al 1. 5% of all energies, transmission factors of 0. 978 and 0. 984, thickness of 1. 5 cm, and effective mass attenuation coefficients of 0. 0144 and 0. 0107 cm² /g had the closest properties to the body tissues in terms of dosimetry characterization. Conclusion: The results revealed that the synthesized bolus could increase the percentage surface dose, reduce skin-sparing effect, and protect OAR. The findings indicated that the synthesized bolus had a potential application in clinical therapy.

Introduction: This study evaluated the effect of Propylene Glycol (PG) on the push-out bond strength of calcium-enriched mixture (CEM) cement compared to mineral trioxide aggregate (MTA). Methods and Materials: The lumens of two hundred 2± 0. 2 mm-thick root sections from human extracted teeth were prepared to achieve a diameter of 1. 3 mm. The samples were then allocated into eight groups of 25 on the basis of the materials used (MTA or CEM cement) and different proportions of PG (0%, 20%, 505, and 100%). In each group, 0. 4 mL of the liquid was mixed with 1 g MTA or CEM cement. After incubation, the push-out strength of the samples was measured using a universal testing machine. Data were analyzed using the two-way ANOVA followed by one-way ANOVA and student’ s t-test. Results: The MTA group showed significantly higher bond strength in comparison with CEM group (P≤ 0. 001). Also 100% and 20% PG increased the bond strength of MTA (P≤ 0. 001). For CEM cement, 100% and 50% PG decreased the bond strength (P≤ 0. 001). Conclusion: This in vitro study demonstrated that while PG increased the push-out bond strength of MTA, it is not recommended for mixing with CEM cement.

The density (ρ ) and speed of sound (u) of the binary mixture (diethylene Glycol monoethyl ether (carbitol) + Propylene Glycol (PG)) have been reported at T= (288. 15, 298. 15, 308. 15 and 318. 15) K. The excess molar volume ( E m V ) and isentropic compressibility deviation (Δ κ s) were calculated using the measured data. The obtained values of ( E m V ) and (Δ κ s) are negative and positive, respectively and become more negative and more positive with increase in carbitol mole fraction. The ρ , u, Vm and κ s values of the mixture were correlated by the Jouyban-Acree model with high accuracy. Furthermore, the calculated E m V and Δ κ s values were correlated well by the Redlich-Kister equation.