H. Razmi , M. Salavati Zadeh ,
Volume 14, Issue 2 (9 2001)
Abstract
The idea of using chemical agents in removal of obstructions on the walls of root canals has been existing since years ago. Successful attempts in this area have been made with the introduction of RC-Prep materials in root canal preparations. The aim of this study was to compare the decalcifing potency of two chelating agents in root canal preparations. 30 extracted canines were divided in three groups for use of Re- Prep materials. Group A Rc-Prep (Primer) made in USA, group B Re- Prep (RC-CTF) made in Iran, and group C as control. Root canals were prepared using standard method followed by washing with 5% sodium hypochloride. Then the teeth were divided into two sections of mesial and distal by a special cutting device. The amount of calcium on polished sections was measured using an elemental analysis method (electron beam probe system). The mean value data were analysed using oneway Analysis of Variance (ANOVA). The mean values for the measured calcium were group A: 28713±1129, group B: 39441+680, and group C: 54458±2024 . Statistical analysis showed that the mean value for group A was significantly different from other groups. There was also significant difference in the mean values for group B and C. The results indicate that the decalcifing potency for Rc-Prep (Primer, USA) is significantly higher (PO.001) than that of Rc-Prep (RC-CTF).
Rahim Asghari Salavat, Ahad Samadi,
Volume 30, Issue 3 (10-2017)
Abstract
Background and Aims: Poor adhesion between porcelain and some of the dental alloys is one of the most challenges to select the desirable alloy in dental restorations. Therefore, the aim of this study was to evaluate the bond strength of porcelain to some of the commercial alloys. This can help in selection of desirable alloy.
Materials and Methods: The shear bond strength of porcelain to the three of the most widely used nickel-base dental alloys commercially named as: Verabond, Damcast and Noritake were evaluated according to standard ASTM E4. The results were analyzed based on the statistical method of independent t with the meaningful level of P<0.05. Then, the bonding interface of the fired samples was evaluated using SEM equipped with EDX analyzer and X-ray diffractometry.
Results: The average bonding strength of porcelain to each of the above mentioned alloys were determined as: 27.54±5.48, 22.46±4.99 and 26.18±4.27 MPa, respectively. Due to the existence of Be and Al in the chemical composition of Verabond and Damcast and their higher appetencies to form the different surface oxides in preference to Cr2O3, not only the bond strength of porcelain to two these alloys was increased about 20 percent (compared with the Noritake), but also the color of their porcelain was not changed.
Conclusion: To replace the replacing of deleterious elements from the chemical composition of dental alloys. The added new elements should control through the oxide layer and the formation of Cr2O3 in porcelain-alloy interfaces for adequate bond strength.
