فهرست مطالب ماهان فاتح زنوزی

To reduce microbial contamination in cases such as perforation treatment, it is necessary to use irrigants after cement placement. The aim of the present study is to investigate the effect of intracanal irrigants on the push out bond strength of CEM, Root MTA and Angelus MTA cements to the dentin wall.

In this laboratory research, 150 cross-section samples from the mid-root region of single canal teeth without caries with a thickness of 1 mm, which were randomly divided into 3 groups of 50 and filled with CEM cement, Root MTA or Angelus MTA, were examined. After the cements were set, the samples of each group were divided into 5 subgroups of 10; 4 subgroups were cleaned with sodium hypochlorite, EDTA, normal saline, 2% chlorhexidine for 30 minutes, and one subgroup was not cleaned as a control group. Then, the push out bond strength of cement with the dentin wall (MPa) and the failure pattern of the samples were evaluated.

Different cleaning methods did not show any significant effect on the bond strength of CEM, Root MTA and Angelus MTA cements. In the cleaning method with saline, the bond strength of Angelus MTA (6.3±1.98) was higher than Root MTA (2.1±3.61) (p=0.004). In the cleaning method with 2% chlorhexidine, the bond strength of Angelus MTA cement (8.72±3.13) was higher compared to CEM (3.87±1.35) and Root MTA (4.66±1.76) (respectively p<0.001 and p=0.001). The most common type of failure in the Angelus MTA group was of the adhesive type, and in the CEM cement and Root MTA groups, it was of the mixed type.

The results of the study showed that different cleaning methods have no effect on the push-out bond strength of the examined cements.

Fluoride compounds are widely used for the control of dental plaque. Considering the effect of different fluoride compounds on the mechanical properties of orthodontic wires, this study was conducted to analyze the effect of different methods of fluoride administration at different concentrations on the load-deflection properties of rhodium-coated NiTi orthodontic archwires.

This clinical trial was conducted on 30 patients aged between 15 and 25 years referring to Babol University of Medical Sciences due to dental crowding and didn't have vertical skeletal defects. 0.016-inch Rhodium-Coated A-NiTi wire was placed on patients' maxillary brackets. Patients were randomly divided into three groups of ten: The control group used only fluoride toothpaste, the second group used fluoride toothpaste with sodium fluoride mouthwash (0.05%) and the third group used fluoride toothpaste with Acidulated Phosphate Fluoride gel (1.23% APF). After six weeks, the values of unloading force (N), yield strength (N/m2) and stiffness (N/m) of the wires were obtained using a three-point bending test.

The mean unloading force and stiffness of the second group wires were higher than that of the other groups and in the first group, they were higher than the control group in all values, but no significant differences were found between the groups. There was a significant difference between the yield strengths of different groups (p=0.038). The mean yield strength in the second group was higher than the other groups (0.94±0.16 N/m2) and was significantly different from the control group (0.75±0.19 N/m2) (p=0.030).

According to this study, method of fluoride administration does not affect the unloading force and stiffness but the yield strength of rhodium-coated NiTi archwires increases with an increase in the fluoride concentration.