[ effect of glass ionomer containing various levels of titanium dioxide nanoparticles against Streptococcus mutans]

The use of nanoparticles in improvement antibacterial property of dental resins is one of the most important issues in recent studies. Studies which added these particles to resin materials have reported desirable results in decreasing bacteria's growth. Titanium dioxide nanoparticles have been proposed for reinforcing fillers in dental resin composites and epoxy. The aim of this study was to evaluate the effect of adding titanium dioxide nanoparticles into a light cure glass ionomer on antibacterial properties of this resin against streptococcus mutans. In this in-vitro study, samples were divided into 5 light cure glass ionomergroups which contain respectively of 0 [as control group], 0.5, 1, 3, 5 weight percentage of nano-titanium dioxide. 15 discs [3 from each experimental group] were cured in plastic frames with 2mm thickness and 8mm diameter, for disc diffusion test. Then antibacterial properties against streptococcus mutans were studied in chocolate agar culture. For Direct Contact Test, 15 micro-tubes containing resin groups [3 discs from each experimental group] were prepared and their antibacterial effect were evaluated after 3, 6 and 24 hours. The data was analyzed by Kruskal-Wallis Test and Mann-Whitney Test. In Disc Diffusion Test the amount of antibacterial effect around discs, containing 0.5 nanoparticles was similar to halo around the other discs containing nanoparticles, and it was little more than control group. In Direct Contact Test, glass ionomers containing nanoparticles, number of bacteria was diminished on surface of resin groups that contain more percentages of nanoparticles at 3, 6, 24 hours,. Four experimental groups did not reveal any significant difference, but it was diminished in compare to control group. However the growth of bacteria in both tests in comparison with control group was decreased, antibacterial property of samples that contain nanoparticles doesn't show any significant difference. This property was more significant in direct contact with bacteria

[Fatigue resistance and failure mode of endodontically restored premolars with indirect composite resin restoration-in vitro]

The present study aimed at determination of the fatigue resistance and failure mode of cusp-replacing onlays in endodontically treated premolars using indirect composite resin restorations. In this experimental study, 84 human premolars were randomly divided into 7 groups of 12. These groups were prepared as follows: Intact teeth used in group1 as control, the second group covers the endodontically treated teeth, restored with indirect onlays using Z-250 composite resin, the next two groups [i.e. 3, 4] were similar to the second group, but subjected to 1 and 2 million fatigue load cycles, respectively. Groups 5, 6, 7 were similar to groups 2, 3, 4, respectively, however, in these groups Tetric Ceram used as the restorative material. All specimens were loaded using a Universal Testing Machine until fracture occurred and the mode of failure observed with naked eye. Kruskal-Wallis and Chi-Square tests were used to analyze the data [alpha=.05]. All specimens withstood the masticating simulation. The mean fracture strength for groups 1 to 7 were: 1276.92, 1269.05, 1217.80, 1188.13, 1228.97, 1127.86, 1105.58, respectively. No statistically significant differences were found between the groups in fracture strength and failure mode. There was no statistically significant difference between two types of resin composite [P=0.203] and load cycles [P=0.298] after zero, 4 and 8 years aging. Within the limitation of this study, restored premolars with indirect composite onlays show fatigue resistance equal to natural tooth up to 8 years after restoration. Furthermore, no statistically significant differences were found between 4 and 8 years of load cycles. Tetric Ceram Z-250 restoration agent showed no effect on the tooth fracture resistance with the most observed fractures to be occur under CEJ with no capability to be restored

[ effect of bleaching products on hardness of glass ionomer cements]

The use of bleaching agents for the sake of whitening teeth has extended for many years. On the other hand, due to the simultaneous presence of a series of tooth colored restorations and existence of few research studies on the effect of different whitening materials on the tooth restorations, the present study with the aim of determining the efficacy of carbamide peroxide on the hardness of Glass Ionomer cements had been emerged. Forty numbers of glass ionomer cylinders were prepared and preserved for 48 hours in 100% humidity and in the room temperature, then were divided into 4 groups each contained 10 samples. The bleaching gel 16% VARI-SHADE [Lochemco USA] was applied for groups I to IV as respectably o, 21, 42, 63 hours. Finally the microhardness of each sample group was measured by Vickers's machine. Microhardness mean was respectively 27.37 +/- 2.4, 25.98 +/- 2.7, 24.41 +/- 3.6 and 26.02 +/- 3.7 in group I to IV, and there was no significant difference between them. Vari-shade bleaching gel did not result to reduced microhardness of Vitremer glass-ionomer in the studied time

[Frequency of antigliadin and anti-transglutaminase in patients with irritable bowel syndrome]

On one hand the prevalence of Irritable Bowel Syndrome [IBS] ranges from 4 to 12 percent in the community; on the other hand, Celiac disease is prevalent in 4% of the IBS patients. Regarding the fact that cereals containing gluten are routinely used in Iran, diagnosing celiac disease in IBSpatients is important for conducting the treatments. The objective of this study was to assess the frequency of Celiac in IBS patients. This study was designed as a case control prospective study. Eighty six subjects were enrolled in this study according to Rome II Criteria. The control group included healthy subjects that were checked up on a routine base. The evaluation of Celiac was done through serology exams such as Anti Gliadin and Anti Transglutaminase [IgG and IgA]. Thirty eight male and 48 female patients suffering from IBS with a mean age of 34 +/- 11.7 years were enrolled in this study. The case and control groups were not significantly different in terms of sex and age. Flatulence, excessive gas passing and mucus passage were the most frequent symptoms in IBS patients. Night symptoms and weight loss [alarm signs] were observed in 37% and 32%, respectively. Elevated Antigliadin Titer was evident in 22 subjects [25%] which suggests a significantly higher rate for the case group as compared to the control group [t=4.67,P=0.0001]. Elevated IgG Anti Transglutaminase Titer was observed in 2 cases [2.3%] while IgA Anti Transglutaminase was not elevated in any of the IBS subjects, neither in the control group nor in the case group. Biopsy of small intestine can be suggested to rule out the elevated Antigliadin Titer Celiac Disease in IBS patients