Comparison of apical microleakage using Ni-Ti with stainless steel finger spreaders

The purpose of this in vitro study was to compare apical microleakage after obturation with Nickel-Titanium [NiTi] compared to Stainless Steel [SS] finger spreaders. Eighty straight single-rooted human teeth were instrumented using step-back technique. The specimens were randomly divided into four groups. The two experimental groups [n=30] and the negative control group [n=10] were obturated by lateral condensation technique with Ariadent gutta-percha and AH26 sealer. The roots in the positive control group [n=10] were instrumented but not obturated. In one group, SS and in another group NiTi spreaders were used. Microleakage evaluation was conducted using dye penetration method t-test was used for statistical analysis. The results showed statistically significant differences between NiTi and SS groups [P=0.022], with the greatest dye penetration in SS group and the least in NiTi group. According to the results of the present study using NiTi spreader decrease apical microleakage in endodontically treated teeth

Effect of different luting cements on fracture resistance in endodontically treated teeth

The aim of the present study was to evaluate the effect of three types of luting cements used for post cementation on the fracture resistance of endodontically treated maxillary premolars, restored with resin composite. One hundred intact single-rooted human maxillary premolars were randomly divided into 5 groups of 20 each. In groups 2-5, post spaces were prepared after root canal treatment and clinical crown reduction up to 1.5 mm above the CEJ. Teeth were divided in groups as follows: Group 1: intact teeth, Group 2: active prefabricated metallic posts [PMP], Group 3: PMP cemented with zinc phosphate luting cement, Group 4: PMP cemented with glass ionomer luting cement and Group 5: PMP cemented with resin luting cement. In groups 2-5 the teeth were restored with resin composite. Following thermocycling, the palatal cusp of each specimen was loaded to compression at an angle of 150? to its longitudinal axis at a strain rate of 2 mm/min until fracture occurred. Data were analyzed using one-way ANOVA and a post hoc Tukey test. Chi-square test was used for comparison of failure mode. There were significant differences in fracture resistance between the test groups [P<0.001]. The differences between group 2 with groups 1, 4 and 5 were statistically significant [P<0.05]; whereas there were no significant differences in fracture resistance between the two other groups [P>0.05]. Furthermore, there were no significant differences in the mode of failure between the 5 groups [P>0.05]. Zinc phosphate, glass ionomer and resin luting cements showed similar behaviors and achieved fracture resistance comparable to intact teeth. However, the use of active post [without cement] adversely affected the fracture resistance of root canal treated teeth

Evaluation of radiation-induced xerostomia in patients with nnasopharyngeal carcinomas

Salivary glands are extremely susceptible to radiation injuries. The aim of this study was to evaluate radiation-induced xerostomia in patients with nasopharyngeal carcinomas, referring to Tabriz Imam Khomeini Hospital in 2005-2006. Thirty patients with nasopharyngeal carcinomas, who received conventional radiotherapy, were included in the present study. The patients' unstimulated saliva samples were collected at three intervals, i.e. before treatment, 3 weeks after the initiation of treatment and at the end of treatment by spitting, and measured with a graduated pipette. The differences in the mean values of the patients' salivary flow rates at three afore-mentioned intervals were statistically significant [p < 0.001]. Two-by-two comparison of the mean values of salivary flow rates of all the patients and of males and females, carried out separately, demonstrated statistically significant differences [p < 0.0025]. However, there were no statistically significant differences between males and females before treatment [p = 0.723], 3 weeks after the initiation of treatment [p = 0.724] and at the end of treatment [p = 0.595]. There were no statistically significant relationships between age and a decrease in salivary flow rate in the total sample [p = 0.76, r = -0.057], in males [p = 0.96, r = 0.011] and in females [p = 0.539, r = -0.208]. Conventional radiotherapy results in severe xerostomia in 3 weeks in patients with nasopharyngeal carcinomas. Age and sex do not influence radiotherapy-induced xerostomia