bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Orthopantomography and Computed Tomography Image for Assessing the Relationship between Impacted Mandibular Third Molar and Mandibular Canal
Authors: Shankar Uma , Hari KR , Reddy T Praveen Kumar , Katakam Shravan Kumar , Janga Deepti 
Published: January 2013

ABSTRACT

Background
Permanent mandibular third molar are most commonly impacted teeth. In planning the surgical removal of mandibular third molar, correct diagnosis requires not only their precise spatial location, but also a thorough and accurate assessment of the intimate relationship with adjacent anatomical structures. Various imaging modalities have been used for localizing the mandibular third molar but not satisfactorily.

Aim
This prospective study of 30 patients with 42 impacted mandibular third molars was carried out with the aim of finding evidence for justifying the use of computed tomography and orthopantomography as a diagnostic modality, prior to surgical intervention of impacted mandibular third molar.

Materials and methods
Subjective evaluation of the CT and OPG images by two observed had shown that there was significant difference between the CT and OPG for radiographic visibility of mandibular canal in relation to third molar.

Results
Data analysis was done with Chi-square test (χ2) and z-test to find the significant difference between the two radiographic modalities OPG and CT in localizing special relationship of impacted mandibular third molar. The comparison of OPG and CT showed z-value >1.5 in darkening of roots (1.98), deflection of root (2.00) interruption of z-value = 0 in narrowing of canal and dark, bifid apexes. Also it showed p-value <0.05 in all the radiographic signs except narrowing of mandibular canal and and dark and bifid apexes.

Conclusion
The spiral CT image provides a unique opportunity to determine the exact position of impacted mandibular third molar and their relationship to adjacent structure in all three planes.

Clinical significance
Computed tomography is highly instrumental in depicting the relationship of mandibular third molar with inferior alveolar nerve canal before treatment and accurate appraisal of the several aspects can be made regarding prognosis.

How to cite this article
Katakam SK, Shankar U, Thakur D, Reddy TPK, Hari KR, Janga D. Comparison of Orthopantomography and Computed Tomography Image for Assessing the Relationship between Impacted Mandibular Third Molar and Mandibular Canal. J Contemp Dent Pract 2012;13(6):819-823.
The Influence of Tray Space and Repeat Pours on the Accuracy of Monophasic Polyvinylsiloxane Impression
Authors: Rajapur Anand , Dixit Santosh , Hoshing Chetan , Raikar Sonal 
Published: January 2013

ABSTRACT

Aim
While literature demonstrates that the optimum accuracy is obtained with the custom trays, the use of stock trays for elastomeric impressions appears to be popular in general practice. The aim of the study was to evaluate the effect of thickness of impression material on the dimensional accuracy of impressions made from monophasic polyvinylsiloxane impression material. This study also studies the dimensional stability of the impressions poured at different time intervals.

Materials and methods
A metal model simulating two abutment teeth was fabricated along with reference lines inscribed on them. Custom impression trays were fabricated with spacer thickness of 2, 4 and 6 mm. impressions were made using monophasic polyvinyl siloxane impression material. The impressions were poured and stone models were obtained. The dimensional accuracy of the impressions were determined indirectly by measuring the dimensional changes of the recovered stone models. The dimensional stability was also evaluated by pouring the impressions at time intervals of 1 hour, 24 hours and 7 days. The obtained data was statistically analyzed.

Results
The results of the study indicated that the impressions made from 2 and 4 mm tray space produced more accurate stone models when compared to 6 mm tray space. There was no significant deviation in the mesiodistal and buccolingual dimensions when impressions were made using impression trays with 2, 4 and 6 mm tray spacers. There was a significant decrease in interabutment distance (p = 0.001) and height of the abutment (p = 0.024) when impressions were made using impression trays with a tray space of 6 mm. There were no significant differences found among the stone models obtained from 1 hour, 24 hours and 1 week pour times.

Conclusion
The mesiodistal and buccolingual dimensions of the abutments were not affected by the variations in thickness of impression material. There was a decrease in the height of the abutment which was clinically not significant. As the thickness of the impression material increased, the interabutment space decreased, which is a factor of concern when impressions are made for fixed partial dentures.

Clinical significance
When monophasic polyvinylsiloxane is used as the impression material, stock trays can be used for making impressions for individual castings.

How to cite this article
Rajapur A, Dixit S, Hoshing C, Raikar S. The Influence of Tray Space and Repeat Pours on the Accuracy of Monophasic Polyvinylsiloxane Impression. J Contemp Dent Pract 2012;13(6):824-829.
Evaluation of Apical Sealing Ability of Four Different Sealers using Centrifuging Dye Penetration Method: An in vitro Study
Authors: Joseph Romel 
Published: January 2013

ABSTRACT

Aim
The aim of this in vitro study was to evaluate the apical seal obtained with four root canal sealers AH 26, Sealapex, Endoflas FS and AH Plus, with lateral condensation.

Materials and methods
Sixty root canals were prepared using the step-back technique. The specimens were divided into four experimental groups of 12 teeth and two control groups of 12 teeth. The experimental groups were obturated by laterally condensed gutta-percha with one of the tested sealers and control groups were obturated without any sealer. Methylene blue dye penetration with centrifuging method was used to evaluate the apical sealing ability. The quantitative apical leakage of each specimen was measured after 2 weeks.

Results
The results showed no significant differences between all groups except between AH Plus and Endoflas FS (<0.05). AH Plus showed significantly less leakage than Endoflas FS.

Conclusion
AH Plus showed the least leakage compared to AH 26, Sealapex and Endoflas FS.

How to cite this article
Joseph R, Singh S. Evaluation of Apical Sealing Ability of Four Different Sealers using Centrifuging Dye Penetration Method: An in vitro Study. J Contemp Dent Pract 2012;13(6):830-833.
An in vitro Investigation into the Cytotoxicity of Methyl Methacrylate Monomer
Authors: Sreekumar AV , Pradeep Nishna 
Published: January 2013

ABSTRACT
Aim of this study was to assess the cytotoxicity of monomer. An in vitro study was designed to study the growth inhibitory effect of monomer (Stellon, Denture Material Improved, Type I, Class I, Dental Products of India Limited) on cells seeded in petri dishes and maintained in an incubator with 5% carbon dioxide at 37°C. The growth of V79 cells (fibroblast cells) maintained in a culture medium to which monomer was added was studied for a period of 5 days. Results of this study pointed out that even at a concentration of 1 μl of monomer, the cell growth was significantly inhibited, when compared to the control group. The number of viable cells decreased dramatically whereas dead cells increased in the culture groups treated with the monomer. The cytotoxic effect was dose dependent. As the concentration increased from 1 to μl there was a marked inhibition of cell growth and a corresponding increase in dead cell count. Results of this study proved beyond doubt that monomer is indeed cytotoxic even in very low concentrations. Thus, it becomes imperative to adopt every possible means to minimize residual monomer content in heat cured resins. Also precautions to minimize tissue contact should be taken while handling monomer by the dentist and dental personnel in the laboratory.

How to cite this article
Pradeep N, Sreekumar AV. An in vitro Investigation into the Cytotoxicity of Methyl Methacrylate Monomer. J Contemp Dent Pract 2012;13(6):838-841.
Management of Large Periapical Cystic Lesion by Aspiration and Nonsurgical Endodontic Therapy using Calcium Hydroxide Paste
Authors: Thomas Kunjamma , Prasanth Dhanapal T , Simon Elsy P 
Published: January 2013

ABSTRACT

Aim
To report a case of conservative nonsurgical management of periapical lesions.

Background
Small periapical lesions of endodontic origin usually heal by conventional endodontic therapy alone. Larger periapical lesions presumed to be cystic may require additional treatment protocols to aid in regression. Conservative nonsurgical management of such lesions eliminates the possible complications of surgery and has wider patient compliance and acceptance.

Case description
A periapical cystic lesion associated with maxillary central incisor and lateral incisor was treated conservatively using buccal aspiration decompression followed by conventional endodontic therapy employing calcium hydroxide iodoform paste as intracanal medicament is reported.

Clinical significance
The treatment was successful as evidenced by relief of symptoms and radiographic evaluation.

Conclusion
Large periapical cyst-like lesions can resolve by nonsurgical endodontic therapy employing calcium hydroxide intracanal interappointment medicament.

How to cite this article
Thomas K, Dhanapal PT, Simon EP. Management of Large Periapical Cystic Lesion by Aspiration and Nonsurgical Endodontic Therapy using Calcium Hydroxide Paste. J Contemp Dent Pract 2012;13(6):897-901.
Psychological Characteristics of Patients Treated by Chronic Maintenance Hemodialysis
Authors: Pop-Jordanova Nada D. , Polenakovic Momir H. 
Published: January 2013

Studies related to psychological aspects of dialysis patients show that depression and anxiety are the most common characteristics. The aim of our study was to analyze the personality profile in patients on chronic maintenance dialysis and to evaluate more specifically the level of depression. The total number of patients was 68 (30 females and 38 males), with mean age 62.3 and 56.5 for females and males respectively. Mean duration of dialysis was 6.73 years for females and 6.68 years for men (the period varied from 0.5 to 18 years). For the evaluation of psychological characteristics, we used two psychometric instruments: Minnesota Multiphase Personality Inventory (MMPI- 201) and Beck Depression Inventory. The obtained results confirmed the presence of depression in patients treated with hemodialysis. The level of depression is variable (minimal is present in 21.43%; mild in 35.71%; moderate in 17.85% and severe in 14.28% of patients). The depression is significantly positively correlated with age (p<0.05) as well as with educational level, and negatively with the duration of dialysis. Specific characteristics of personality obtained with MMPI are hypersensitivity, depressive mood, and withdrawal from friends and relatives. More specific emotional traits are the accentuated anxiety, low level of hostility, but very high passive aggression which destroys their social communications. Some response measures for depression such as relaxation training, psychological support, music therapy, or peripheral biofeedback are recommended.
Compréhension en lecture au primaire : actualisation des pratiques enseignantes
Authors: Martel Virginie , Lévesque Jean-Yves , Aubin-Horth Shanoussa 
Published: January 2013

Afin de dresser le portrait actuel des pratiques enseignantes en matière de compréhension en lecture aux deuxième et troisième cycles du primaire, la présente recherche a établi les objectifs et les pratiques pédagogiques de 413 enseignantes et enseignants de différentes régions du Québec. Alors que les études réalisées au tournant des années 2000 laissaient penser que les enseignants référaient à des pratiques pédagogiques relativement traditionnelles et peu tournées vers l’enseignement de stratégies, les résultats de cette recherche démontrent que les enseignantes et enseignants déclarent mettre en oeuvre des objectifs et des pratiques pédagogiques liés au rôle de la personne enseignante comme modèle-lecteur et à la nécessité de proposer un contexte d’enseignement et d’apprentissage signifiant, réflexif et stratégique.
Azine Dyes
Authors: Smith Roy E. ,   Updated by Staff
Published: January 2013

AbstractAzine, oxazine, and thiazine dyes were among the earliest dyes. The names are derived from the 6‐membered heterocyclic ring present in all dyes of these classes: 1,4‐diazine; 1,4‐oxazine, and 1,4‐thiazine.The parent rings are always included in phenazine, phenoxazine, and phenothiazine. The first of these dyes to be made synthetically was Perkin's mauveine. These dyes were historically more important then they are at present. However, a few are still used today. All of these dyes are vattable, ie, they are reduced to colorless forms, then oxidized back to the dye. They therefore offer good fastness to oxidation. Because of this property, many find use as redox indicators in titrations. Methylene Blue is a classic thiazine dye and is still very popular today. It is used in textile dyeing, basic uses are for dyeing acrylic fibers, leather, and coloring of paper. It is also used as a biologically active photosensitizer and is useful in the diagnosis and treatment of medical conditions. Methylene Blue‐curcumin is used in the treatment of Alzheimer's disease.
Dimethylformamide
Authors: Marsella John A. ,   Updated by Staff
Published: January 2013

AbstractDimethylformamide is a clear, hygroscopic liquid with a slight amine odor. It was first synthesized in 1893 by heating a mixture of sodium formate and dimethylammonium chloride and later prepared by direct reaction of dimethylamine with formic acid. Although it does not occur widely in nature, traces of DMF have been detected in sausages, cooked mushrooms, grapes, and wine. The solvent properties of DMF are particularly attractive. Because of its high dielectric constant, aprotic nature, wide liquid range, and low volatility, it is frequently used for chemical reactions and other applications requiring high dissolving power. DMF is often referred to as the universal solvent. Important uses are in the production and processing of polymers. It is used as a spinning solvent for polyacrylonitrile fiber and polyurethane fiber (Spandex), and production of synthetic leather. It is also used in many processes in the production of pharmaceuticals. DMF is not used in a consumer setting so its toxicity is relatively low.
Dye Carriers
Authors: de Guzman Ernesto , Sutton Boyce ,   Updated by Staff
Published: January 2013

Abstract
Dye carriers are needed for complete dye penetration of polyester fibers. Carriers cause glass‐transition of the polyester polymer to become lower and allow penetration of water‐insoluble dyes into the fiber. It is difficult for dye solutions in water to penetrate synthetic fibers such as polyester, cellulose triacetate, polyamides, and polyacrylics which are somewhat hydrophobic. Disperse dyes commonly used to dye polyester are nonionic and dye the polyester through a diffusion mechanism. Deep shades and full fastness properties can be achieved with carriers using disperse dyes and carriers. The formulation of a carrier depends on: the carrier‐active chemical compound; the emulsifier; special additives; and environmental concerns. Dyeing procedures vary according to fiber content of the textile material and the equipment to be used. Textile dyeing is the largest industry that uses dye carriers, but dye carriers are found in other dyeing processes such as in hair dyes and dyeing of plastic.
Fracture Mechanics
Authors: Recho Naman 
Published: January 2013

AbstractFracture mechanics consist in studying the interaction between a geometric discontinuity (crack) and the surrounding continuum, as well as the evolution of this discontinuity.On one hand fracture mechanics is concerned with the description of mechanical fields in the neighborhood of the tip of the crack and the energies that are associated therewith and on the other hand, it deals with the evaluation of the harmfulness of a crack in terms of its propagation.
Talc
Authors: McCarthy Edward F. ,   Updated by Staff
Published: January 2013

Abstract
Talc is a naturally occurring mineral that is a crystalline hydrous magnesium silicate belonging to the general mineral family of the layered silicates. Other layered silicates are kaolin, mica, and pyrophyllite. The commercial value of a talc ore is based on its color, purity, accessibility, proximity to the market, and accessory minerals. Of these the most critical is color. Most talc is mined by open‐pit methods, but there are some underground mines. Mining of talc is very sensitive to contamination during the mining process. Information of mining and processing are given.
The FDA has studied talc used in cosmetics for asbestos. Samples were considered safe, but monitoring continues. Talc is used for in a wide variety of applications. In all of these applications, talc is a functional ingredient. Talc is rarely used as a filler since it is expensive. Uses for talc include in ceramics (principal use), paper, roofing, paint, plastics, rubber, cosmetics, agriculture and food.
Climate Change, Freshwater Ecosystems
Authors: Kernan Martin , Battarbee Richard W. , Moss Brian 
Published: January 2013

AbstractThis article considers the interactions between climate change and other drivers of change including hydromorphological modification, acid deposition, contamination by toxic substances using evidence from laboratory experiments, field experiments, and modeling. This article evaluates these processes in relation to extreme events, seasonal changes, in ecosystems, trends over the decades, mitigation strategies, and ecosystem recovery.Aspects of hydrophysical, hydrochemical, and ecological change can be used as early indicators of climate change in aquatic ecosystems and it addresses implications for the future climate change for freshwater ecosystems management at the catchment scale
Climate Change, Crop Adaptation
Authors: Yadav Shyam S. , Redden Robert J. , Hatifield Jerry L. , Hall Anthony E. , Lotze‐Campen Hermann 
Published: January 2013

AbstractThe publication of the Stern Review on the Economics of Climate Change and the Fourth Assessment Report by the Intergovernmental Panel on Climate Change in 2007 have pushed the scientific and public debate on climate change a decisive step forward. It is now beyond doubt that anthropogenic greenhouse gas emissions are the main cause of the recently observed climate change. The agricultural sector is directly affected by changes in temperature, precipitation, and carbon dioxide concentrations in the atmosphere. If global temperature increases beyond 2°C world food security could be threatened, given a continuous increase in world population to unprecedented levels above 9 billion this century.This article covers issues related to both crops and climatic conditions. Climate stress on crops and solutions to counteract these stresses are discussed. Some of the solutions reported are the development of drought and temperature resistant species, crossing food crops with their wild relatives and other genetic engineering solutions. Seed banks and their maintenance are also discussed. The development of energy crops is a strategy to produce alternating energy without impacting food security and impact on the environment and is a possibility. the need for research on crop improvement is presented as are some examples of studies made.
Fischer–Tropsch Process
Authors: de Klerk Arno 
Published: January 2013

AbstractA Fischer–Tropsch process always forms part of a larger indirect liquefaction facility, which consists of three processing steps. The first step is to convert a carbon source, such as coal, natural gas, biomass, or organic waste, into synthesis gas (syngas). Syngas is a mixture of hydrogen and carbon monoxide, and it is the feed material for a Fischer–Tropsch process, which is the second step in the indirect liquefaction process. Fischer–Tropsch synthesis is the catalytic polymerization and hydrogenation of CO, which produces a synthetic crude oil (syncrude). The syncrude is a multiphase mixture of hydrocarbons, oxygenates, and water. The third step is the refining of the syncrude to products that are traditionally produced from conventional crude oil, such as transportation fuels and petrochemicals. The current contribution deals only with the Fischer–Tropsch process; the generation of syngas and the refining of Fischer–Tropsch syncrude are not discussed in any detail. A Fischer–Tropsch process has three main elements: catalyst, reactor, and gas loop. Fischer–Tropsch catalysis is described to explain the relationship among the different catalyst types, operating conditions, and products. A description of the main syncrude types and their compositions is also provided. Fischer–Tropsch technologies are discussed, with an explanation of the relationship between catalyst and reactor, the tradeoffs involved in different catalyst–reactor combinations, as well as guidelines for technology selection. The role of the Fischer–Tropsch gas loop is outlined, with a discussion of the key elements of the gas loop and how they affect the overall performance of a Fischer–Tropsch process.
Solar Energy Harvesting: Power Electronics Interfaces and Control
Authors: Khaligh Alireza , Dusmez Serkan 
Published: January 2013

AbstractAmong renewable energy sources such as biomass, tidal, minihydro, microturbines, and wind, solar energy is one of the most promising sustainable energy resources. Solar energy is converted to electrical energy in photovoltaic (PV) cells through a process called photovoltaic effect. The output voltage polarity of the PV cell is direct current (DC) whose magnitude depends on the connection type of PV cells/modules, while the output current or power mainly varies with solar irradiance. One of the primary tasks in PV systems is to convert the output DC voltage of PV modules to alternate current (AC) to energize general‐purpose AC loads and utility connection. In addition, an interface, which regulates and adjusts the output voltage of the PV, is required because the output voltage of the PV system varies with various factors such as irradiation and temperature. Meanwhile, the power extracted from the PV system must be optimized based on the weather conditions to get the highest efficiency.A PV system is a combination of several components such as PV panels, energy storage system (ESS), and power conditioning units (PCUs). In PV systems, PCU is composed of power electronic converters along with special controls/algorithms, and it is responsible for various tasks including ESS charging, maximum power point tracking (MPPT), and DC–AC conversion. This article aims to describe a complete PV system architecture and design by following design steps: PV cell/module/array modeling, MPPT algorithms and implementation, design and control of DC/DC power electronic converters responsible for MPPT operation, and DC/AC inverter to supply general‐purpose AC loads. In addition to the provided basic concepts, an example of a complete stand‐alone PV system design including the system sizing has been presented. The designed system has been simulated, and detailed results are provided.