Comparing of retention of cast crowns cemented with two kind of permanent cement with and without prier use of temporary cement

Introduction: This study evaluated the effects of eugenol –free temporary cement remnants on the retentive strength of casting crowns luted via zinc phosphate and resin cement (Maxcem) to the tooth structure. Material and methods: 40 extracted human molars ware randomly divided into 2 groups. each group was then divided into 2 subgroups and the teeth were paired so that the size of each tooth in each subgroup was the same as a tooth in the other subgroups. 40 standardized Ni-cr complete crowns were made on teeth prepared with a milling machine using conventional laboratory techniques. For each adhesive system, in one subgroups a provisional restoration was cemented using an eugenol –free temporary cement. Temporary crown was remained on the tooth structure for an hour and then extracted and cement remnant was removed by an excavator. Then the casing crowns were adhesively luted via zinc phosphate, adhesive resin(Maxcem) to prepared teeth. After 24h storage in distilled water, Retention was evaluated by measuring the tensile force required to dislodge the crowns from tooth preparations with a universal testing machine after thermo cycling (1500 cycles between 5c and 55c with 1- minute dwell times). The data were analyzed by means of paired T-test and wilcoxon test in SPSS software version 11.5 Results: The analysis showed the mean retentive strength for 2 subgroups with and without prior use of temporary cement in the maxcem group was 176 ± 55 and 274 ± 169 N, there was not a significant difference between the 2 subgroups. (p value = 0.174). And the mean retentive strength for 2 subgroups with and without prior use of temporary cement in the zincphosphate group was 257 ± 125 and 238 ± 135 N, there was not significan t difference between the 2 subgroups (p value = 0.782). Discussion: The use of an eugenol –free temporary cement does not alter the retentive strength of casting restorations lutted to prepared teeth using the tested adhesive system, when temporary cements are removed properly

Prosthodontic Rehabilitation of the Patient with Severely Worn Dentition: A Case Report

The management of tooth wear has been a subject of increasing interest from both preventive and restorative points of view. This paper describes the full mouth rehabilitation of a 63-year-old bruxer man with a severely worn dentition and other dental problems including unsuitable restorations and several missing teeth. The treatment entailed using cast posts and cores, metal-ceramic restorations, and a removable partial denture. As with the treatment procedure of such cases, equal-intensity centric occlusal contacts on all teeth and an anterior guidance in harmony with functional jaw movements were especially taken into account

Removal of Cationic Surfactants from Aqueous Solutions by Modified Cotton as a Novel High Capacity and Low Cost Adsorbent

Direct and indirect releases of large quantities of surfactants to the environment may result in serious health and environmental problems. Therefore, surfactants should be removed from water before release to the environment or delivery for public use. Using cotton-based adsorbent may be an effective technique to remove surfactants. In this study, the removal of cationic surfactants by modified cotton was investigated. N-Cetyl-N,N,N-trimethylammonium bromide (CTAB) was selected as a cationic surfactant for the experiments. The results revealed that the modified cotton has a high affinity toward the cationic surfactants. Experiments were conducted to examine the effects of applied adsorbent dosage, initial concentration of adsorbate, pH, temperature, salt concentration on the removal efficiency. By increasing the salt concentration, removal efficiency was decreased slightly. The temperature had an adverse effect on removal efficiency. The adsorption of the CTAB increases with increasing pH of the solution. A series of batch experiments were performed to determine the sorption isotherms of modified cotton. Surfactant equilibrium data fitted very well to the Langmuir model. The Langmuir model showed that the maximum adsorption was 909 mg/g which is higher than the capacity of other adsorbents reported until now. The pseudo first-, second- order and corresponding rate equation kinetic models were investigated. Adsorption complies with a pseudo-second-order rate equation

Observing the Cross-Infection Control Among Dental Clinics and Laboratories

Introduction: Dentists and all related oral hygiene occupations are endanger of cross contamination because of close contacts with patients. Dental laboratories are one of those which have a direct contact with dentist and cross infection control plays an important role to prevent exposure to pathogens. According to the fact that many dental laboratories are not well informed about cross infection control; the aim of this study is to prepare a questionnaire for evaluating both dentists and dental laboratories knowledge about cross control infections. Materials & Methods: 250 dentist and 50 dental laboratories were randomly chosen and prepared questionnaire distributed. The collected data were analyzed by SPSS software and Chi-Square test. Results: There was no significant differences between general and post graduated dentist in using gloves, masks and protective eye glasses (p value > 0.05).the results showed no significant differences in uses of protective eye glasses between dentist who worked in clinics and private offices (p value = 0.384), but there was significant differences in using gloves (p value = 0.02).condensation silicones (90.5%) and alginates (90%) were the most impression materials and 88% of dentist rinsed the impressions always while 0.8% never did that. Conclusion: The cross control infection is no

Ecosystem services and economic values provided by urban park trees in the air polluted city of Mashhad

Estimates of air pollutant removal by urban park trees in heavily polluted city of Mashhad, Iran, the associated economic value and the impact on air quality improvement are the main contributors of this study. The economic value of Mellat Park is substantial with a benefit-cost ratio at 0.6; however, the design of Mellat Park has not been adopted in accordance with air quality condition. While carbon emissions is not substantial, a significant part of Mellat Park's value (53.5 %) arises from carbon sequestration. Regarding PM2.5, the most harmful air pollutant, there was a decline in air quality. The economic analysis of the park's three most frequent and three most valuable species highlights the inconsistency between the tree species and the environmental demands. If Acer rubrum (the most valuable species) or Paulownia (the second most valuable species) had been planted rather than Platanus orientalis (the most common species), the park's tree value would have seen 2.7 times increase and a 41.8 % boost. Local scale design considering the link between air pollution and vegetation configuration -including landscape for vegetation and superior plant species - can maximize value of the park's trees on removal rates and air quality improvement

Pomegranate marketing margins in the Neyriz, Neyriz Iran

Marketing agricultural products, while establishing a balance between supply and demand in various stages of production to final consumption, stabilize farm income and satisfy consumer demand. Therefore, agricultural marketing study seems necessary. In this study, pomegranate marketing in Neyriz city of Fars province was investigated and its various marketing channels were evaluated, also. The results showed that, the share of Pomegranate growers and marketing margin are almost good. Lack of suitable storage and fridge was one of the major problems of pomegranate growers. For improvement the current situation, recommended formation cooperative Pomegranate growers in the region for decreasing production costs and making storages and fridges enough for regulation demand and supply

Estimating the Water Demand Function of Pardis City

Population growth, rising living standards, and rapid urbanization give rise to increasing water demands. One of the important challenges that policymakers face is the integrated view of water resources management by giving priority to water demand.   In this study, the water demand in Pardis City was estimated using the Stone-Geary Utility Function which was used to calculate price and income elasticity. Results showed that the range of price elasticity was 0.08 to 0.321 and that the income elasticity ranged from 0.165 to 0.289. Increasing water price had a greater effect on decreasing water consumption, particularly where water consumption was higher. Moreover, price elasticity in the summer was greater than in other seasons. Price elasticity was greater in higher consumption blocks  than in lower consumption ones. Results also indicated that domestic price elasticity was twice the non-domestic and that price elasticity was less than 1 in all cases

An Interdisciplinary Approach for Rehabilitating a Patient with Amelogenesis Imperfecta: A Case Report

Amelogenesis imperfecta (AI) has been defined as a group of hereditary enamel defects. It can be characterized by enamel hypoplasia, hypomaturation, or hypocalcification of the teeth. AI may be associated with some other dental and skeletal developmental defects. Restoration for patients with this condition should be oriented toward the functional and esthetic rehabilitation. This clinical report describes the oral rehabilitation of a young patient diagnosed with the hypoplastic type of AI in posterior teeth and hypomatured type of AI in anterior teeth

Optimization Model of Hirmand River Basin Water Resources in the Agricultural Sector Using Stochastic Dynamic Programming under Uncertainty Conditions

In this study, water management allocated to the agricultural sector’ was analyzed using stochastic dynamic programming under uncertainty conditions. The technical coefficients used in the study referred to the agricultural years, 2013-2014. They were obtained through the use of simple random sampling of 250 farmers in the region for crops wheat, barley, melon, watermelon and ruby grapes under the scenarios of drought, wet, normal, and water required in the most sensitive growth stages. Production function and profit function were obtained from the yield-water-product function of crops using Eviews software. Expected net profit of the system and optimal allocation of water were also calculated based on the GAMS economic analysis software. The results revealed that 14% of the cases over the past 30 years had wet years (high), 47% of the time and that 39% had experienced drought (low) and normal (average) years. In the best case, i.e. with high current levels, respectively at, 58, 67, 54, and 48% of water requirements for these crops and, in the worst case (with low current levels), 47, 35, 49, 53 and 48% of the water requirements provided during the most sensitive growth stages. Moreover, the results showed that the cultivation of the ruby grape was the best product with the highest expected profit in normal and rainfall conditions. In general, when the expected value of net profit is positive, managers would act optimistically and they would promise the optimal level of water provided to the farmers. Conversely, when the net value is negative they would prefer to be more conservative and would promise a lesser amount of water provided to the farmers. Hence, if the promised water to the farmer is not wasted, he will choose the loss incurred from a lesser harvest

Estimation of greenhouse unit’s efficiency for planning sustainable culture pattern (The case study: Zabol city, Iran)

Iran due to specific climatic conditions and water restriction is a country that requires substantial revision in the structure of culture and development; in this regard greenhouse cultivation can be presented as a suitable way. In this study the technical efficiency units of cucumber greenhouse in Zabol and the following sections were calculated using data envelopment analysis and application of linear programming models. Data needed to complete the study questionnaire 42 cucumbers greenhouse units were collected in the city of Zabol. Results showed that the average efficiency of Zabol city was equal to 71 percent. Technical efficiency was estimates equal to one for 38 percent of the greenhouses, too. Greenhouse technical efficiency in subsectors of Zabol (Shibab, central, Miankangi and Postab) was 88, 81, 64, 50 percent, respectively