Evaluation of the Effect of Different Ferrule Designs on Fracture Resistance of Maxillary Incisors Restored with Bonded Posts and Cores

Introduction: In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve. So in these cases we should use different ferrule designs.This in vitro study investigated the effect of different ferrule designs on the fractureresistance of teeth restored with bonded post and cores.Materials and Methods: Forty freshly-extracted central incisors were endodontically treated. The teeth were randomly divided into four groups; group 1 were teeth with 2 mm circumferential ferrule above the CEJ, group 2 were teeth with 2 mm ferrule only on the palatal side of the teeth, group 3 consisted of teeth with 2 mm ferrule only on the facial side and group 4 were teeth with 2 mm ferrule on the palatal and facial side of teeth with interproximal concavities.All teeth were restored with fiber posts and composite cores. The specimen was mounted on a universal testing machine and compressive load was applied to the long axis of the specimen until failure occurred.Results: The fracture resistance was 533.79 ± 232.28 in group 1, 634.75± 133.35 in group 2, 828.90 ±118.27 in group 3 and 678.78± 160.20 in group 4. The post hoc analysis showed statistically significant difference between groups 1 and 3 .Conclusions: The results of this in vitro study showed that facial ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post and cores

Evolution of hepatitis B virus surface gene and protein among Iranian chronic carriers from different provinces

Background and Objectives: Iranian chronic HBV carrier�s population has shown a unique pattern of genotype D distribution all around the country. The aim of this study was to explore more details of evolutionary history of carriers based on structural surface proteins from different provinces. Materials and Methods: Sera obtained from 360 isolates from 12 Different regions of country were used for amplification and sequencing of surface proteins. A detailed mutational analysis was undertaken. Results: The total ratio for Missense/Silent nucleotide substitutions was 0.96. Sistan and Kermanshah showed the lowest rate of evolution between provinces (P = 0.055). On the other hand, Khorasan Razavi and Khoozestan contained the highest ratio (P = 0.055). The rest of regions were laid between these two extremes. Azarbayjan and Guilan showed the highest proportion of immune epitope distribution (91.3 and 96, respectively). Conversely, Sistan and Tehran harbored the least percentage (66.6 and 68.8, respectively). Kermanshah province contained only 5.2, whereas Isfahan had 54.5 of B cell epitope distribution. In terms of T helper epitopes, all provinces showed a somehow homogeneity: 22.58 (Fars) to 46.6 (Khuzestan). On the other hand, distribution of substitutions within the CTL epitopes showed a wide range of variation between 6.6 (Khuzestan) and 63 (Kermanshah). Conclusion: Further to low selection pressure found in Iranian population, the variations between different regions designate random genetic drift within the surface proteins. These finding would have some applications in terms of specific antiviral regimen, design of more efficient vaccine and public health issues. © 2015, Tehran University of Medical Science. All rights reserved

Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion

Insecticidal efficacy of silica nanoparticles against Rhyzopertha dominica F. and Tribolium confusum Jacquelin du Val

Bioassays were conducted to assess the effects of two silicon dioxide nanoparticles of Aerosil® and Nanosav against adults of Rhyzopertha dominica F. and Tribolium confusum Jacquelin du Val. Silica nanoparticles were applied at the rates of 50, 100, 200 and 300 mg · kg–1 on wheat and peeled barley. The mortality was counted after 1, 2, 3, and 7 days of exposure. Another experiment was carried out to evaluate the effect of food source on the survival of beetles after exposure to silica nanoparticles. Adults were exposed to silica nanoparticles at the rate of 0.2 mg · cm–2 for 1 and 2 days on filter paper inside plastic Petri dishes, respectively. After exposure, the initial mortality was counted and live individuals of both species were held for a week in empty glass vials or vials containing wheat and wheat flour, respectively. Silica nanoparticles have high toxicity on R. dominica and T. confusum adults. Rhyzopertha dominica was more susceptible than T. confusum. However, the mortality of both species increased with increasing concentrations and time exposed to each concentration. At low concentrations, Aerosil® was more effective than Nanosav. Silica nanoparticles were more effective in wheat grains than barley. Results indicated that the initial mortality was so high that the impact of food source on delay mortality was unclear in most cases. Silica nanoparticles were efficient against tested species and can be used effectively in a stored grain integrated pest management program