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Sample records for mg-to-cl molar ratio

  1. Influence of alcohol: oil molar ratio on the production of ethyl esters ...

    African Journals Online (AJOL)

    The influence of alcohol:oil molar ratio on the canola oil transesterification reaction in solvent-free medium using free lipase from Thermomyces lanuginosus and Burkholderia cepacia was studied. The experiments conducted in batch reactor for 72 h at 37°C in cosolvent-free reaction system with ethanol addition in three ...

  2. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.

    Science.gov (United States)

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

    2014-11-26

    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. The effects of alcohol to oil molar ratios and the type of alcohol on biodiesel production using transesterification process

    Directory of Open Access Journals (Sweden)

    Idris Atadashi Musa

    2016-03-01

    Full Text Available The nature of alcohol and alcohol to oil molar ratio plays an important role on the method of biodiesel production. As a result, this paper examined different alcohols commonly used for the production of biodiesel fuel with more emphasis on methanol and ethanol. Further the different alcohol to oil molar ratios used for the production of biodiesel have been extensively discussed and reported. Also the effects of alcohol to molar ratios on biodiesel refining process and its physicochemical properties were investigated.

  4. Determination of Ca/P molar ratio in hydroxyapatite (HA) by X-ray fluorescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Scapin, Marcos A.; Guilhen, Sabine N.; Cotrim, Marycel E.B.; Pires, Maria Ap. F., E-mail: mascapin@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Hydroxyapatite (HA) is a mineral composed of calcium phosphate employed for endodontics, restorative dentistry and other applications in orthopedics and prosthesis. Additionally, this biomaterial is an inexpensive but efficient adsorbent for the removal of heavy metals and other unwanted species of contaminated liquid effluents. This is especially interesting when low-cost effective remediation is required. A Ca / P molar ratio of 1.667 is consistent with the theoretical Ca / P ratio for calcium hydroxyapatite with a compositional formula of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, which properties are well discussed in the literature. The aim of this work was to implement and validate a methodology for simultaneous determination of major and minor constituents in the hydroxyapatite (HA) as well as providing the Ca / P molar ratio. To accomplish these achievements, wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) was applied. This is a non-destructive technique that requires no chemical treatment, enabling fast chemical analysis in a wide variety of samples, with no hazardous waste being generated as a result of the process of determination. A standard reference material from NIST (SRM 1400 – Bone Ash) was used to validate the methodology for the determination of magnesium, phosphorus, potassium, calcium, iron, zinc, strontium and the Ca / P ratio in HA samples by WDXRF. The Z-score test was applied as a statistical tool and showed that the calculated values were of less than 1.8 for all the measured analytes. (author)

  5. Determination of Ca/P molar ratio in hydroxyapatite (HA) by X-ray fluorescence technique

    International Nuclear Information System (INIS)

    Scapin, Marcos A.; Guilhen, Sabine N.; Cotrim, Marycel E.B.; Pires, Maria Ap. F.

    2015-01-01

    Hydroxyapatite (HA) is a mineral composed of calcium phosphate employed for endodontics, restorative dentistry and other applications in orthopedics and prosthesis. Additionally, this biomaterial is an inexpensive but efficient adsorbent for the removal of heavy metals and other unwanted species of contaminated liquid effluents. This is especially interesting when low-cost effective remediation is required. A Ca / P molar ratio of 1.667 is consistent with the theoretical Ca / P ratio for calcium hydroxyapatite with a compositional formula of Ca 10 (PO 4 ) 6 (OH) 2 , which properties are well discussed in the literature. The aim of this work was to implement and validate a methodology for simultaneous determination of major and minor constituents in the hydroxyapatite (HA) as well as providing the Ca / P molar ratio. To accomplish these achievements, wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) was applied. This is a non-destructive technique that requires no chemical treatment, enabling fast chemical analysis in a wide variety of samples, with no hazardous waste being generated as a result of the process of determination. A standard reference material from NIST (SRM 1400 – Bone Ash) was used to validate the methodology for the determination of magnesium, phosphorus, potassium, calcium, iron, zinc, strontium and the Ca / P ratio in HA samples by WDXRF. The Z-score test was applied as a statistical tool and showed that the calculated values were of less than 1.8 for all the measured analytes. (author)

  6. Selenium:Mercury Molar Ratios in Freshwater Fish from Tennessee: Individual, Species, and Geographical Variations have Implications for Management

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael; Jeitner, C.; Donio, M.; Pittfield, T.

    2014-01-01

    Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy’s Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

  7. Selenium: Mercury Molar Ratios in Freshwater Fish in the Columbia River Basin: Potential Applications for Specific Fish Consumption Advisories.

    Science.gov (United States)

    Cusack, Leanne K; Eagles-Smith, Collin; Harding, Anna K; Kile, Molly; Stone, Dave

    2017-07-01

    Fish provide a valuable source of beneficial nutrients and are an excellent source of low fat protein. However, fish are also the primary source of methylmercury exposure in humans. Selenium often co-occurs with mercury and there is some evidence that selenium can protect against mercury toxicity yet States issue fish consumption advisories based solely on the risks that methylmercury pose to human health. Recently, it has been suggested the selenium: mercury molar ratio be considered in risk management. In order for agencies to utilize the ratio to set consumption guidelines, it is important to evaluate the variability in selenium and mercury in different fish species. We examined 10 different freshwater fish species found within the Columbia River Basin in order to determine the inter- and intra-specific variability in the selenium: mercury molar ratios and the selenium health benefit values. We found significant variation in selenium: mercury molar ratios. The mean molar ratios for each species were all above 1:1, ranging from 3.42:1 in Walleye to 27.2:1 in Chinook salmon. There was a positive correlation between both mercury and selenium with length for each fish species apart from yellow perch and rainbow trout. All species had health benefit values greater than 2. We observed considerable variability in selenium: mercury molar ratios within fish species collected in the Columbia River Basin. Although incorporating selenium: mercury molar ratios into fish consumption holds the potential for refining advisories and assessing the risk of methylmercury exposure, the current understanding of how these ratios apply is insufficient, and further understanding of drivers of variability in the ratios is needed.

  8. Selenium: Mercury molar ratios in freshwater fish in the Columbia River Basin: Potential applications for specific fish consumption advisories

    Science.gov (United States)

    Cusack, Leanne K.; Eagles-Smith, Collin A.; Harding, Anna K.; Kile, Molly; Stone, Dave

    2017-01-01

    Fish provide a valuable source of beneficial nutrients and are an excellent source of low fat protein. However, fish are also the primary source of methylmercury exposure in humans. Selenium often co-occurs with mercury and there is some evidence that selenium can protect against mercury toxicity yet States issue fish consumption advisories based solely on the risks that methylmercury pose to human health. Recently, it has been suggested the selenium: mercury molar ratio be considered in risk management. In order for agencies to utilize the ratio to set consumption guidelines, it is important to evaluate the variability in selenium and mercury in different fish species. We examined 10 different freshwater fish species found within the Columbia River Basin in order to determine the inter- and intra-specific variability in the selenium: mercury molar ratios and the selenium health benefit values. We found significant variation in selenium: mercury molar ratios. The mean molar ratios for each species were all above 1:1, ranging from 3.42:1 in Walleye to 27.2:1 in Chinook salmon. There was a positive correlation between both mercury and selenium with length for each fish species apart from yellow perch and rainbow trout. All species had health benefit values greater than 2. We observed considerable variability in selenium: mercury molar ratios within fish species collected in the Columbia River Basin. Although incorporating selenium: mercury molar ratios into fish consumption holds the potential for refining advisories and assessing the risk of methylmercury exposure, the current understanding of how these ratios apply is insufficient, and further understanding of drivers of variability in the ratios is needed.

  9. Influence of Ni/Co molar ratio on electromagnetic properties and microwave absorption performances for Ni/Co paraffin composites

    Energy Technology Data Exchange (ETDEWEB)

    Yan, S.J., E-mail: shaojiuyan@126.com [Department of Structural Steel, Functional Materials and Heat Treatment Processing, AVIC Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Aviation Key Laboratory of Science and Technology on Stealth Materials, Beijing 100095 (China); Dai, S.L. [The Office of AVIC Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Ding, H.Y.; Wang, Z.Y. [Aviation Key Laboratory of Science and Technology on Stealth Materials, Beijing 100095 (China); Liu, D.B [Department of Structural Steel, Functional Materials and Heat Treatment Processing, AVIC Beijing Institute of Aeronautical Materials, Beijing 100095 (China)

    2014-05-01

    Ni and Co metallic microparticles with submicron size were synthesized with a simple wet chemical reduction method at a relatively low temperature. Then their morphologies and structures were characterized by SEM and XRD. Ni metallic microparticles have spherical-shape morphology with fcc crystalline structure, however, Co has a distinct leaf-like morphology with the fcc and hcp mixed phases crystalline structures. For the characterization of their electromagnetic properties, paraffin matrix composites containing different molar ratio Ni and Co mixture powder as fillers were prepared. It was found that both the electromagnetic properties and electromagnetic microwave absorption performances of absorber layer were remarkably influenced by Ni/Co molar ratio. The electromagnetic microwave absorption performances were significantly improved by blending Ni and Co metallic microparticles into paraffin matrix with changing Ni/Co molar ratio, and enhanced mechanism were discussed. - Highlights: • Ni and Co microparticles were synthesized by a wet chemical reduction method. • EM properties of absorber were remarkably influenced by Ni/Co molar ratio. • EMA performances can be adjusted by artificially changing Co/Ni molar ratio. • Enhanced EMA performances result from multiple EM attenuation mechanisms.

  10. Bioactivity tests of calcium phosphates with variant molar ratios of main components.

    Science.gov (United States)

    Pluta, Klaudia; Sobczak-Kupiec, Agnieszka; Półtorak, Olga; Malina, Dagmara; Tyliszczak, Bożena

    2018-03-09

    Calcium phosphates constitute attractive materials of biomedical applications. Among them particular attention is devoted to bioactive hydroxyapatite (HAp) and bioresorbable tricalcium phosphate (TCP) that possess ability to bind to living bones and can be used clinically as important bone substitutes. Notably, in vivo bone bioactivity can be predicted from apatite formation of bone immersed in SBF fluids. Thus, analyses of behavior of calcium phosphates immersed in various bio fluids are of great importance. Recently, stoichiometric HAp and TCP structures have been widely studied, whereas only limited number of publications have been devoted to analyses of nonstoichiometric calcium phosphates. Here, we report physicochemical analysis of natural and synthetic phosphates with variable Ca/P molar ratios. Subsequently attained structures were subjected to incubation in either artificial saliva or Ringer's fluids. Both pH and conductivity of such fluids were determined before and after incubation. Furthermore, the influence of the Ca/P values on such parameters was exemplified. Physicochemical analysis of received materials was performed by XRD and FT-IR characterization techniques. Their potential antibacterial activity and behavior in the presence of infectious microorganisms as Escherichia coli and Staphylococcus aureus was also evaluated. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018. © 2018 Wiley Periodicals, Inc.

  11. Corneal Stromal Cell Growth on Gelatin/Chondroitin Sulfate Scaffolds Modified at Different NHS/EDC Molar Ratios

    Directory of Open Access Journals (Sweden)

    Jui-Yang Lai

    2013-01-01

    Full Text Available A nanoscale modification strategy that can incorporate chondroitin sulfate (CS into the cross-linked porous gelatin materials has previously been proposed to give superior performance for designed corneal keratocyte scaffolds. The purpose of this work was to further investigate the influence of carbodiimide chemistry on the characteristics and biofunctionalities of gelatin/CS scaffolds treated with varying N-hydroxysuccinimide (NHS/1-ethyl-3-(3-dimethyl aminopropyl carbodiimide hydrochloride (EDC molar ratios (0-1 at a constant EDC concentration of 10 mM. Results of Fourier transform infrared spectroscopy and dimethylmethylene blue assays consistently indicated that when the NHS to EDC molar ratio exceeds a critical level (i.e., 0.5, the efficiency of carbodiimide-mediated biomaterial modification is significantly reduced. With the optimum NHS/EDC molar ratio of 0.5, chemical treatment could achieve relatively high CS content in the gelatin scaffolds, thereby enhancing the water content, glucose permeation, and fibronectin adsorption. Live/Dead assays and interleukin-6 mRNA expression analyses demonstrated that all the test samples have good cytocompatibility without causing toxicity and inflammation. In the molar ratio range of NHS to EDC from 0 to 0.5, the cell adhesion ratio and proliferation activity on the chemically modified samples significantly increased, which is attributed to the increasing CS content. Additionally, the materials with highest CS content (0.143 ± 0.007 nmol/10 mg scaffold showed the greatest stimulatory effect on the biosynthetic activity of cultivated keratocytes. These findings suggest that a positive correlation is noticed between the NHS to EDC molar ratio and the CS content in the biopolymer matrices, thereby greatly affecting the corneal stromal cell growth.

  12. Phosphorus release from anaerobic peat soil during convective discharge – effect of soil Fe:P molar ratio and preferential flow

    DEFF Research Database (Denmark)

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    2014-01-01

    soils (TOC from 5 to 39%) with a gradient in Fe:P molar ratio (molar ratio between bicarbonate dithionite extractable Fe and P (FeBD:PBD) from 3 to 112) and degree of non-equilibrium (preferential) flow. Short-term batch incubation experiments (21 days) indicated that concurrent Fe and P release...

  13. Anomalous viscosity behavior of a bicelle system with various molar ratios of short-and long-chain phospholipids

    International Nuclear Information System (INIS)

    Hwang, Jimmy S.; Oweimreen, Ghassan A.

    2003-01-01

    Viscosity versus temperature curves were obtained for five DMPC/DHPC/H2O bilayer systems with DMPC/DHPC molar ratios of 3.2, 2.8, 2.5, 2.0 and 1.5. The curves showed the viscosity maxima that shifted to higher temperatures as the mole fraction of DHPC increased. The maxima are extremely high for the first three systems and are estimated to be no less than 600 Pa,s. The shift to higher temperature is explained in terms of decrease in the the coalescence of the bicells as the mole fraction of DHPC increases. The maxima are attributed to two competing effects; the normal decrease in viscosity with temperature is counterbalanced at low to moderate temperatures with an increase in viscosity resulting from coalescence. Such coalescence increases as the DMPC /DHPC molar ratio increases. (author)

  14. Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio

    Energy Technology Data Exchange (ETDEWEB)

    Priolisi, Ornella, E-mail: ornella.priolisi@depretto.gov.it [ITIS “De Pretto” (Italy); Fabrizi, Alberto, E-mail: fabrizi@gest.unipd.it [University of Padova, Department of Management and Engineering (Italy); Deon, Giovanna, E-mail: giovanna.deon@depretto-vi.it [ITIS “De Pretto” (Italy); Bonollo, Franco, E-mail: bonollo@gest.unipd.it [University of Padova, Department of Management and Engineering (Italy); Cattini, Stefano, E-mail: stefano.cattini@unimore.it [University of Modena and Reggio Emilia, Department of Engineering Enzo Ferrari (Italy)

    2016-01-15

    In this work the morphology evolution of Au nanoparticles (AuNPs), obtained by direct reduction, was studied as a function of time, temperature, and Au(III)/sodium ascorbate molar ratio. The NPs morphology was examined by transmission electron microscope with image analysis, while time evolution was investigated by visible and near-infrared absorption spectroscopy and dynamic light scattering. It is found that initially formed star-like NPs transform in more spheroidal particles and the evolution appears more rapid by increasing the temperature while a large amount of reducing agent prevents the remodeling of AuNPs. An explication of morphology evolution is proposed.

  15. Co-production of acetone and ethanol with molar ratio control enables production of improved gasoline or jet fuel blends.

    Science.gov (United States)

    Baer, Zachary C; Bormann, Sebastian; Sreekumar, Sanil; Grippo, Adam; Toste, F Dean; Blanch, Harvey W; Clark, Douglas S

    2016-10-01

    The fermentation of simple sugars to ethanol has been the most successful biofuel process to displace fossil fuel consumption worldwide thus far. However, the physical properties of ethanol and automotive components limit its application in most cases to 10-15 vol% blends with conventional gasoline. Fermentative co-production of ethanol and acetone coupled with a catalytic alkylation reaction could enable the production of gasoline blendstocks enriched in higher-chain oxygenates. Here we demonstrate a synthetic pathway for the production of acetone through the mevalonate precursor hydroxymethylglutaryl-CoA. Expression of this pathway in various strains of Escherichia coli resulted in the co-production of acetone and ethanol. Metabolic engineering and control of the environmental conditions for microbial growth resulted in controllable acetone and ethanol production with ethanol:acetone molar ratios ranging from 0.7:1 to 10.0:1. Specifically, use of gluconic acid as a substrate increased production of acetone and balanced the redox state of the system, predictively reducing the molar ethanol:acetone ratio. Increases in ethanol production and the molar ethanol:acetone ratio were achieved by co-expression of the aldehyde/alcohol dehydrogenase (AdhE) from E. coli MG1655 and by co-expression of pyruvate decarboxylase (Pdc) and alcohol dehydrogenase (AdhB) from Z. mobilis. Controlling the fermentation aeration rate and pH in a bioreactor raised the acetone titer to 5.1 g L(-1) , similar to that obtained with wild-type Clostridium acetobutylicum. Optimizing the metabolic pathway, the selection of host strain, and the physiological conditions employed for host growth together improved acetone titers over 35-fold (0.14-5.1 g/L). Finally, chemical catalysis was used to upgrade the co-produced ethanol and acetone at both low and high molar ratios to higher-chain oxygenates for gasoline and jet fuel applications. Biotechnol. Bioeng. 2016;113: 2079-2087. © 2016 Wiley

  16. Continuous production of biofuel from refined and used palm olein oil with supercritical methanol at a low molar ratio

    International Nuclear Information System (INIS)

    Sakdasri, Winatta; Sawangkeaw, Ruengwit; Ngamprasertsith, Somkiat

    2015-01-01

    Highlights: • Continuous production of biofuel in SCM at low molar ratio was studied. • The actual density of mixture was applied to calculate residence times. • The maximum FAME of 80–90% was observed for refined and used palm oils. • The glycerol–methanol reaction showed a positive effect in fuel yield. - Abstract: The high energy consumption and high environmental impact in the supercritical methanol (SCM) process primarily originates from the preheating of reactants and the recovery of excess alcohols. This work demonstrated the synthesis of biofuel using a lowered methanol to oil molar ratio of 12:1, instead of the 40:1–42:1 ratios that are commonly employed in conventional SCM. The apparent density of the reacting mixture was measured and applied to accurately calculate residence times in a continuous reactor. The effects of residence time were considered from 10 to 25 min. The results revealed that excessive residence times reduced the ester content, especially for unsaturated esters, in the resulting biofuel. A residence time of 20 min was recommended to simultaneously achieve a maximum ester content of 90% and a triglyceride conversion of up to 99%. Used palm olein oil with high free fatty acid (4.56 wt.%) can be employed as a feedstock and give a maximum ester content of 80%. In addition, the side reaction between glycerol and methanol at 400 °C and 15 MPa showed a positive effect in increasing fuel yield by 2%–7%

  17. Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: variation within species and relevance to risk communication.

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2013-07-01

    There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 are at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: Variation within species and relevance to risk communication

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2015-01-01

    There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 may be at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. PMID:23541437

  19. Molar volume, excess enthalpy, and Prigogine-Defay ratio of some silicate glasses with different (P,T) histories.

    Science.gov (United States)

    Wondraczek, Lothar; Behrens, Harald

    2007-10-21

    Structural relaxation in silicate glasses with different (p,T) histories was experimentally examined by differential scanning calorimetry and measurements of molar volume under ambient pressure. Temperature and pressure-dependent rates of changes in molar volume and generation of excess enthalpy were determined for sodium trisilicate, soda lime silicate, and sodium borosilicate (NBS) compositions. From the derived data, Prigogine-Defay ratios are calculated and discussed. Changes of excess enthalpy are governed mainly by changes in short-range structure, as is shown for NBS where boron coordination is highly sensitive to pressure. For all three glasses, it is shown how the relaxation functions that underlie volume, enthalpy, and structural relaxation decouple for changes in cooling rates and pressure of freezing, respectively. The magnitude of the divergence between enthalpy and volume may be related to differences in structural sensitivity to changes in the (p,V,T,t) space on different length scales. The findings suggest that the Prigogine-Defay ratio is related to the magnitude of the discussed decoupling effect.

  20. Selenium and mercury molar ratios in saltwater fish from New Jersey: Individual and species variability complicate use in human health fish consumption advisories☆

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2014-01-01

    Balancing risk versus benefits to humans and other organisms from consuming fish is a national concern in the USA, as well as in many other parts of the world. Protecting public health is both a federal and state responsibility, and states respond by issuing fish consumption advisories, particularly for mercury. Recently it has been emphasized that the protective role of selenium against mercury toxicity depends on their molar ratios, which should be evaluated as an indication of selenium’s protective capacity, and incorporated in risk assessments for fish consumption. However, there is no single “protective” ratio agreed upon. In this paper we examine the selenium:mercury (Se:Hg) molar ratios in a wide range of saltwater fish caught and eaten by recreational fishers along the New Jersey coast. We were particularly interested in interspecific and intraspecific variability, and whether the molar ratios were consistent within a species, allowing for its use in managing risk. The selenium–mercury molar ratio showed significant variation among and within fish species. The molar ratio decreased with the size of the fish species, decreased with the mercury levels, and within a fish species, the selenium:mercury ratio decreased with fish size. As an essential element, selenium undergoes some homeostatic regulation, but it is also highly toxic. Within species, mercury level tends to increase with size, accounting for the negative relationship between size and ratio. This variability may make it difficult to use the selenium:mercury molar ratio in risk assessment, risk management, and risk communication at this time, and more information is needed on how mercury and selenium actually interact and on the relationship between the molar ratios and health outcomes. PMID:22405995

  1. Adsorption of tetracycline on Fe (hydr)oxides: effects of pH and metal cation (Cu2+, Zn2+ and Al3+) addition in various molar ratios

    Science.gov (United States)

    Hsu, Liang-Ching; Liu, Yu-Ting; Syu, Chien-Hui; Huang, Mei-Hsia; Teah, Heng Yi

    2018-01-01

    Iron (Fe) (hydr)oxides control the mobility and bioavailability of tetracycline (TC) in waters and soils. Adsorption of TC on Fe (hydr)oxides is greatly affected by polyvalent metals; however, impacts of molar metal/TC ratios on TC adsorptive behaviours on Fe (hydr)oxides remain unclear. Results showed that maximum TC adsorption on ferrihydrite and goethite occurred at pH 5–6. Such TC adsorption was generally promoted by the addition of Cu2+, Zn2+ and Al3+. The greatest increase in TC adsorption was found in the system with molar Cu/TC ratio of 3 due to the formation of Fe hydr(oxide)–Cu–TC ternary complexes. Functional groups on TC that were responsible for the complexation with Cu2+shifted from phenolic diketone groups at Cu/TC molar ratio adsorption at a molar Al/TC ratio of 1. However, TC adsorption decreased for Al/TC molar ratio > 1 as excess Al3+ led to the competitive adsorption with Al/TC complexes. For the Zn2+ addition, no significant correlation was found between TC adsorption capacity and molar Zn/TC ratios. PMID:29657795

  2. Potential Moderating Effects of Selenium on Mercury Uptake and Selenium:Mercury Molar Ratios in Fish From Oak Ridge and Savannah River Site - 12086

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Joanna; Gochfeld, Michael; Donio, Mark [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey 08854-8082 (United States); Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854 (United States); Jeitner, Christian; Pittfield, Taryn [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey 08854-8082 (United States); Consortium for Risk Evaluation with Stakeholder Participation (CRESP), Rutgers University and Vanderbilt University, Nashville, Tennessee 37235 (United States)

    2012-07-01

    Mercury contamination is an important remediation issue at the U.S. Department of Energy's (DOE) Oak Ridge Reservation and to a lesser extent at other DOE sites because of the hazard it presents, potential consequences to humans and eco-receptors, and completed pathways, to offsite receptors. Recent work has emphasized that selenium might ameliorate the toxicity of mercury, and we examine the selenium:mercury (Se:Hg) molar ratios in fish from Oak Ridge, and compare them to Se:Hg molar ratios in fish from the Savannah River. Selenium/mercury molar ratios varied considerably among and within fish species. There was considerable variation in the molar ratios for individual fish (as opposed to mean ratios by species) for freshwater fish from both sites. The inter-individual variation in molar ratios indicates that such that the molar ratios of mean Se and Hg concentrations may not be representative. Even for fish species with relatively low mercury levels, some individual fish have molar ratios less than unity, the value sometime thought to be protective. Selenium levels varied narrowly regardless of fish size, consistent with homeostatic regulation of this essential trace element. The data indicate that considerable attention will need to be directed toward variations and variances, as well as the mechanisms of the interaction of selenium and mercury, before risk assessment and risk management policies can use this information to manage mercury pollution and risk. Even so, if there are high levels of selenium in the fish from Poplar Creek on Oak Ridge, then the potential exists for some amelioration of adverse health effects, on the fish themselves, predators that eat them, and people who consume them. This work will aid DOE because it will allow managers and scientists to understand another aspect that affects fate and transport of mercury, as well as the potential effects of methylmercury in fish for human and ecological receptors. The variability within fish

  3. Phytate/calcium molar ratio does not predict accessibility of calcium in ready-to-eat dishes.

    Science.gov (United States)

    Erba, Daniela; Manini, Federica; Meroni, Erika; Casiraghi, Maria C

    2017-08-01

    Phytic acid (PA), a naturally occurring compound of plant food, is generally considered to affect mineral bioavailability. The aim of this study was to investigate the reliability of the PA/calcium molar ratio as a predictive factor of calcium accessibility in composed dishes and their ingredients. Dishes were chosen whose ingredients were rich in Ca (milk or cheese) or in PA (whole-wheat cereals) in order to consider a range of PA/Ca ratios (from 0 to 2.4) and measure Ca solubility using an in vitro approach. The amounts of soluble Ca in composed dishes were consistent with the sum of soluble Ca from ingredients (three out of five meals) or higher. Among whole-wheat products, bread showed higher Ca accessibility (71%, PA/Ca = 1.1) than biscuits (23%, PA/Ca = 0.9) and pasta (15%, PA/Ca = 1.5), and among Ca-rich ingredients, semi-skimmed milk displayed higher Ca accessibility (64%) than sliced cheese (50%) and Parmesan (38%). No significant correlation between the PA/Ca ratio and Ca accessibility was found (P = 0.077). The reliability of the PA/Ca ratio for predicting the availability of calcium in composed dishes is unsatisfactory; data emphasized the importance of the overall food matrix influence on mineral accessibility. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  4. The Optimization of Copper Sulfate and Tincalconite Molar Ratios on the Hydrothermal Synthesis of Copper Borates

    OpenAIRE

    E. Moroydor Derun; N. Tugrul; F. T. Senberber; A. S. Kipcak; S. Piskin

    2014-01-01

    In this research, copper borates are synthesized by the reaction of copper sulfate pentahydrate (CuSO4.5H2O) and tincalconite (Na2O4B7.10H2O). The experimental parameters are selected as 80oC reaction temperature and 60 of reaction time. The effect of mole ratio of CuSO4.5H2O to Na2O4B7.5H2O is studied. For the identification analyses X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques are used. At the end of the experiments, synthesized...

  5. Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: Potential protection on mercury toxicity by selenium

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

    2014-01-01

    A number of factors affect the consumption risk from mercury in fish, including mercury levels, seasonal patterns of mercury concentrations, human consumption patterns, and sensitive populations (e.g. pregnant women, fetuses, young children, and yet unknown genetic factors). Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for saltwater fish. We examine levels of mercury and selenium in several species of fish and seabirds from the Aleutians (Alaska), determine selenium:mercury molar ratios, and examine species-specific and individual variation in the ratios as a means of exploring the use of the ratio in risk assessment and risk management. Variation among species was similar for mercury and selenium. There was significant inter-specific and intraspecific variation in selenium:mercury molar ratios for fish, and for birds. The mean selenium:mercury molar ratios for all fish and bird species were above 1, meaning there was an excess of selenium relative to mercury. It has been suggested that an excess of selenium confers some protective advantage for salt water fish, although the degree of excess necessary is unclear. The selenium:mercury molar ratio was significantly correlated negatively with total length for most fish species, but not for dolly varden. Some individuals of Pacific cod, yellow irish lord, rock greenling, Pacific halibut, dolly varden, and to a lesser extent, flathead sole, had selenium:mercury ratios below 1. No bird muscle had an excess of mercury (ratio below 1), and only glaucous-winged gull and pigeon guillemot had ratios between 1 and 5. There was a great deal of variation in selenium:mercury molar ratios within fish species, and within bird species, making it difficult and impractical to use these ratios in risk assessment or management, for fish advisories, or for consumers, particularly given the difficulty of interpreting the ratios. PMID:22664537

  6. Structural, Surface Morphology and Optical Properties of ZnS Films by Chemical Bath Deposition at Various Zn/S Molar Ratios

    Directory of Open Access Journals (Sweden)

    Fei-Peng Yu

    2014-01-01

    Full Text Available In this study, ZnS thin films were prepared on glass substrates by chemical bath deposition at various Zn/S molar ratios from 1/50 to 1/150. The effects of Zn/S molar ratio in precursor on the characteristics of ZnS films were demonstrated by X-ray diffraction, scanning electron microscopy, optical transmittance, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry. It was found that more voids were formed in the ZnS film prepared using the precursor with Zn/S molar ratio of 1/50, and the other ZnS films showed the denser structure as the molar ratio was decreased from 1/75 to 1/150. From the analyses of chemical bonding states, the ZnS phase was indeed formed in these films. Moreover, the ZnO and Zn(OH2 also appeared due to the water absorption on film surface during deposition. This would be helpful to the junction in cell device. With changing the Zn/S molar ratio from 1/75 to 1/150, the ZnS films demonstrate high transmittance of 75–88% in the visible region, indicating the films are potentially useful in photovoltaic applications.

  7. Influence of variation in molar ratio on co-amorphous drug-amino acid systems

    DEFF Research Database (Denmark)

    Jensen, Katrine Birgitte Tarp; Larsen, Flemming Hofmann; Löbmann, Korbinian

    2016-01-01

    Molecular interactions were investigated within four different co-amorphous drug-amino acid systems, namely indomethacin-tryptophan (Ind-Trp), furosemide-tryptophan (Fur-Trp), indomethacin-arginine (Ind-Arg) and furosemide-arginine (Fur-Arg). The co-amorphous systems were prepared by ball milling...... observed in the 50mol% drug (1:1M ratio) mixtures, with the exception of co-amorphous Ind-Arg where the interactions within the 40mol% drug samples appear equally strong. A particularly large deviation between the theoretical and actual Tgs was observed within co-amorphous Ind-Arg and Fur-Arg systems......-amorphous mixture without additional interactions. The modified equation described the Tgs of the co-amorphous Ind-Arg with excess Arg less well indicating possible further interactions; however, the FTIR and ssNMR data did not support the presence of additional intermolecular drug-amino acid interactions....

  8. Na/Cl molar ratio changes during a salting cycle and its application to the estimation of sodium retention in salted watersheds.

    Science.gov (United States)

    Sun, Hongbing; Huffine, Maria; Husch, Jonathan; Sinpatanasakul, Leeann

    2012-08-01

    Using soil column experiments and data from natural watersheds, this paper analyzes the changes in Na/Cl molar ratios during a salting cycle of aqueous-soil systems. The soil column experiments involved introducing NaCl salt at various initial concentrations into multiple soil columns. At the start of a salting cycle in the column experiments, sodium was adsorbed more than chloride due to cation exchange processes. As a result, the initial Na/Cl molar ratio in column effluent was lower than 1, but increased thereafter. One-dimensional PHREEQC geochemical transport simulations also were conducted to further quantify these trends under more diverse scenarios. The experimentally determined Na/Cl molar ratio pattern was compared to observations in the annual salting cycle of four natural watersheds where NaCl is the dominant applied road deicing salt. Typically, Na/Cl molar ratios were low from mid-winter to early spring and increased after the bulk of the salt was flushed out of the watersheds during the summer, fall and early winter. The established relationship between the Na/Cl molar ratios and the amount of sodium retention derived from the column experiments and computer simulations present an alternative approach to the traditional budget analysis method for estimating sodium retention when the experimental and natural watershed patterns of Na/Cl molar ratio change are similar. Findings from this study enhance the understanding of sodium retention and help improve the scientific basis for future environmental policies intended to suppress the increase of sodium concentrations in salted watersheds. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

    Directory of Open Access Journals (Sweden)

    Guadalupe de la Lanza Espino

    Full Text Available The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC, nitrogen (TN, phosphorus (TP, elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1. Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1 than those closer to the channel axis (averaging 341-516 µmol g(-1; p <0.05. The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1, whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1; p<0.05. The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4 indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16% than those near the channel axis (50.0 to 66 µmol g(-1; 0.15 to 0.21%. C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP. We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

  10. Synthesis and electrochemical analysis of polyaniline/TiO2 composites prepared with various molar ratios between aniline monomer and para-toluenesulfonic acid

    International Nuclear Information System (INIS)

    Oh, Misoon; Kim, Seok

    2012-01-01

    Graphical abstract: Polyaniline (PANI)/TiO 2 composites were prepared by in situ polymerization using para-toluenesulfonic acid (p-TSA). The composites showed different morphology and specific capacitances as a function of aniline concentration, which are related to the morphology (shape or size) of particles. Scheme of the formation of composites consisting of PANI film and the micelle structures is shown. Highlights: ► PANI/TiO 2 composite were prepared with a different concentration of monomer and dopant. ► Aniline/acid ratio influenced the morphological and electrochemical properties. ► The composites showed different capacitances as a function of aniline concentrations. ► Aniline/acid ratio could influence on the dispersion and surface roughness of particles. - Abstract: Polyaniline (PANI)/titanium dioxide (TiO 2 ) composites were prepared with a chemical oxidation polymerization of aniline monomer (ANI) with various molar ratios between ANI and para toluenesulfonic acid (p-TSA). To find an effect of the [ANI]:[p-TSA] molar ratio on the electrochemical properties of the prepared PANI/TiO 2 composites, the composites were synthesized under same conditions except the p-TSA concentrations. The prepared composite films had more homogeneous TiO 2 dispersion with changing [ANI]:[p-TSA] molar ratios from 6:1 to 1:1. p-TSA surfactant-like doping acid helped the dispersion of TiO 2 particles in the PANI matrix. PANI covering the TiO 2 surfaces was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Prepared PANI films on the TiO 2 particles had the smoothest surface when the ANI and p-TSA had 1:1 molar ratio in the reaction solution. The composite prepared with molar ratio [ANI]:[p-TSA] of 3:1 had the highest capacitance (800 F g −1 ) among the prepared composites.

  11. Adsorption of Nitrite and Nitrate Ions from an Aqueous Solution by Fe-Mg-Type Hydrotalcites at Different Molar Ratios.

    Science.gov (United States)

    Ogata, Fumihiko; Nagai, Noriaki; Kariya, Yukine; Nagahashi, Eri; Kobayashi, Yuhei; Nakamura, Takehiro; Kawasaki, Naohito

    2018-01-01

    In this study, we prepared Fe-Mg-type hydrotalcites (Fe-HT3.0 and Fe-HT5.0) with different molar ratios and evaluated their adsorption capability for nitrite and nitrate ions from aqueous solution. Fe-HT is a typical hydrotalcite-like layered double hydroxide. Adsorption isotherms, as well as the effects of contact time and pH were investigated, and it was found that Fe-HT can adsorb larger amounts of nitrite and nitrate ions than Al-HT (normal-type hydrotalcite). Adsorption isotherm data were fitted to both Freundlich (correlation coefficient: 0.970-1.000) and Langmuir (correlation coefficient: 0.974-0.999) equations. Elemental analysis and binding energy of Fe-HT surface before and after adsorption indicated that the adsorption mechanism was related to the interaction between the adsorbent surface and anions. In addition, the ion exchange process is related to the adsorption mechanism. The adsorption amount increased with increasing temperature (7-25°C). The experimental data fit the pseudo-second-order model better than the pseudo-first-order model. The effect of pH on adsorption was not significant, which suggested that Fe-HT could be used over a wide pH range (4-12). These results indicate that Fe-HT is a good adsorbent for the removal of nitrite and nitrate ions from aqueous solution.

  12. Effect of ammonium carbonate to metal ions molar ratio on synthesis and sintering of Nd:YAG nanopowders

    Science.gov (United States)

    Liu, Qiang; Chen, Cong; Dai, Jiawei; Hu, Zewang; Chen, Haohong; Li, Jiang

    2018-06-01

    Using the nanopowders synthesized by a reverse co-precipitation method, neodymium doped yttrium aluminum garnet (Nd:YAG) transparent ceramics were fabricated by vacuum sintering method. The influence of ammonium carbonate to metal ions (NH4HCO3/M3+) molar ratio (R value) on the properties of Nd:YAG precursors and powders, as well as the densification, microstructure, and transmittance of the resultant ceramics was systematically investigated. The results show that the precursors have similar compositions and the calcined powders have pure Y3Al5O12 (YAG) phase. However, the R value is closely related to the morphologies of the precursors and powders. It is found that the powder with R = 3.0 has strongest agglomeration and the powders with R = 3.2-4.0 show better dispersity. Using these powders as starting materials, the corresponding ceramics were sintered at 1720 °C for 20 h in vacuum. As a result, the ceramic with R = 3.2 obtains the best transmittance of about 72% at the wavelength of 1064 nm. The grain growth exponent and activation energy of the Nd:YAG ceramics fabricated from the powder with R = 3.2 were also studied.

  13. Defluoridation of drinking water by combined electrocoagulation: effects of the molar ratio of alkalinity and fluoride to Al(III).

    Science.gov (United States)

    Zhao, Hua-Zhang; Yang, Wei; Zhu, Jun; Ni, Jin-Ren

    2009-03-01

    The defluoridation efficiency (epsilon(F)) of electrocoagulation (EC) is closely related to the pH level of the F(-)-containing solution. The pH level usually needs to be adjusted by adding acid in order to obtain the highest epsilon(F) for the F(-)-containing groundwater. The use of combined EC (CEC), which is the combination of chemical coagulation with EC, was proposed to remove fluoride from drinking water for the first time in this study. The optimal scheme for the design and operation of CEC were obtained through experiments on the treatment of F(-)-containing groundwater. It was found, with OH(-) being the only alkalinity of the raw water, that the highest efficiency would be obtained when the molar ratio of alkalinity and fluoride to Al(III) (gamma(Alkalinity+F)) was controlled at 3.0. However, when the raw water contained HCO(3)(-) alkalinity, a correction coefficient was needed to correct the concentration of HCO(3)(-) to obtain the optimal defluoridation condition of gamma(Alkalinity+F)=3.0 for CEC. The correction coefficient of HCO(3)(-) concentration was concluded as 0.60 from the experiment. For the practical F(-)-containing groundwater treatment, CEC can achieve similar epsilon(F) as an acid-adding EC process. The consumption of aluminum electrode was decreased in CEC. The energy consumption also declined greatly in CEC, which is less than one third of that in the acid-adding EC process.

  14. Molar ratios of therapeutic water-soluble phenothiazine⋅water-insoluble phospholipid adducts reveal a Fibonacci correlation and a putative link for structure–activity relationships

    DEFF Research Database (Denmark)

    Keyzer, Hendrik; Fey, S. J.; Thornton, Barry

    2015-01-01

    1,2diacyl-sn-glycero-3-phospholipids (PL) with even-numbered symmetric saturated diacyl chains with the headgroups choline (PC), glycerol (PG), serine (PS), ethanolamine (PE), phosphatidic acid (PA). We observed water soluble products with replicable molar ratios (MR) that could be divided into two...

  15. Effect of NH4-N/P and Ca/P molar ratios on the reactive crystallization of calcium phosphates for phosphorus recovery from wastewater

    DEFF Research Database (Denmark)

    Vasenko, Liubov; Qu, Haiyan

    2017-01-01

    In this work, the effects of operational parameters, initial phosphorus concentration and molar ratios of Ca/P and NH4-N/P (further in the text N/P), on the nature and purity of precipitated phosphorus products have been investigated in an artificial system that mimics the supernatant in wastewater...

  16. Effect of Molecular Weight and Molar Ratio of Dextran on Self-Assembly of Dextran Stearate Polymeric Micelles as Nanocarriers for Etoposide

    Directory of Open Access Journals (Sweden)

    Jaleh Varshosaz

    2012-01-01

    Full Text Available Amphiphilic polymer surfactants are composed of hydrophilic and hydrophobic polymers and are widely used in targeted drug delivery. The purpose of this study was the evaluation of the effect of molecular weight and molar ratio of dextran on physicochemical properties of dextran stearate polymeric micelles. Dextran stearate was synthesized by acylation of dextran with stearoyl chloride. Etoposide loaded polymeric micelles were prepared by dialysis method. The resulting micelles were evaluated for particle size, zeta potential, critical micelle concentration (CMC, drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of micelles were studied in CT-26 colorectal carcinoma cell line. Molecular weight and molar ratio of dextran-stearate were impressive on zeta potential, CMC, drug loading capacity, and release efficiency. Unlike polymer molecular weight, molar ratio of stearate had a significant effect on cytotoxicity and particle size of etoposide loaded micelles. Although molecular weight of dextran had no significant effect on cytotoxicity of micelles on CT-26 cells, it had drastic attributes for stability of polymeric micelles. Consequently, both variables of molecular weight of dextran and molar ratio of stearate should be taken into account to have a stable and effective micelle of dextran-stearate.

  17. Influence of S/Mn molar ratio on the morphology and optical property of γ-MnS thin films prepared by microwave hydrothermal

    International Nuclear Information System (INIS)

    Yu, Xin; Li-yun, Cao; Jian-feng, Huang; Jia, Liu; Jie, Fei; Chun-yan, Yao

    2013-01-01

    Highlights: ► The influence of the precursor solution molar ratio of S/Mn. ► The degree of orientation of the γ-MnS film decrease slightly with increasing the S/Mn from 2.0 to 4.0. ► Film quality is strongly affected by the initial nucleation. ► The absorption edge obviously shifts to a higher wavelength with the increase of the S/Mn molar ratio from 2.0 to 4.0. - Abstract: Well crystallized γ-MnS thin films were successfully synthesized at low temperature and short processing time via a novel microwave hydrothermal (M-H) process without any complexing agent by using manganese chloride and thioacetamide as source materials. The influence of different S/Mn molar ratio in the precursor solution on the phase compositions, morphologies and optical properties of the as-deposited films was investigated. The as-deposited γ-MnS thin films were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and ultraviolet–visible (UV–vis). Results show that the wurtzite phase γ-MnS thin films with good crystallization can be achieved when S/Mn molar ratio is controlled at 2.0–4.0. The deposited γ-MnS thin films exhibit (1 0 0) orientation growth with the thickness of 300–500 nm. With the increase of S/Mn molar ratio from 2.0 to 4.0, the orientation growth is weakened while the dense and uniform of the as-deposited γ-MnS thin films are obviously improved and the corresponding band gap of the thin films increase from 3.88 to 3.97 eV.

  18. Decreased Serum IGF-1/IGFBP-3 Molar Ratio is Associated with Executive Function Behaviors in Type 2 Diabetic Patients with Mild Cognitive Impairment.

    Science.gov (United States)

    Huang, Rong; Wang, Pin; Han, Jing; Xia, Wenqing; Cai, Rongrong; Sun, Haixia; Sun, Jie; Wang, Shaohua

    2015-01-01

    Insulin-like growth factor (IGF)-1, through insulin/IGF-1 signaling pathway, is involved in the pathogenesis of type 2 diabetes mellitus (T2DM) and Alzheimer's disease. This study aimed to assess the association of serum IGF-1 and IGF binding protein (IGFBP)-3 levels with cognition status and to determine whether IGF-1 rs972936 polymorphism is associated with T2DM with mild cognitive impairment (MCI). A total of 150 T2DM patients, 75 satisfying the MCI diagnostic criteria and 75 exhibiting healthy cognition, were enrolled in this study. The cognitive function of the subjects was extensively assessed. Serum IGF-1 and IGFBP-3 levels were measured through enzyme-linked immunosorbent assay; IGF-1/IGFBP-3 molar ratio was calculated. Single nucleotide polymorphisms of the IGF-1-(rs972936) gene were analyzed. Serum IGF-1/IGFBP-3 molar ratio in MCI patients was significantly lower than that in the control group (p = 0.003). Significant negative correlations were found between IGF-1/IGFBP-3 molar ratio and Trail Making Test A and B (TMT-A and TMT-B) scores (p = 0.003; p function. Further multiple step-wise regression analysis revealed that the TMT-A or TMT-B score was significantly associated only with serum IGF-1/IGFBP-3 molar ratio (p = 0.016; p IGF-1 rs972936 polymorphism between MCI and control groups. A low serum IGF-1/IGFBP-3 molar ratio is associated with the pathogenesis of MCI, particularly executive function in T2DM populations. Further investigation with a large population size should be conducted to confirm this observed association.

  19. Mercury and selenium levels, and selenium:mercury molar ratios of brain, muscle and other tissues in bluefish (Pomatomus saltatrix) from New Jersey, USA

    Science.gov (United States)

    Burger, Joanna; Jeitner, Christian; Donio, Mark; Pittfield, Taryn; Gochfeld, Michael

    2015-01-01

    A number of contaminants affect fish health, including mercury and selenium, and the selenium: mercury molar ratio. Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for consumption of saltwater fish. Yet the relative ameliorating effects of selenium on toxicity within fish have not been examined, nor has the molar ratio in different tissues, (i.e. brain). We examined mercury and selenium levels in brain, kidney, liver, red and white muscle, and skin and scales in bluefish (Pomatomus saltatrix) from New Jersey to determine whether there were toxic levels of either metal, and we computed the selenium: mercury molar ratios by tissues. Total mercury averaged 0.32 ± 0.02 ppm wet weight in edible muscle and 0.09 ± 0.01 ppm in brain. Selenium concentration averaged 0.37 ± 0.03 in muscle and 0.36 ± 0.03 ppm in brain. There were significant differences in levels of mercury, selenium, and selenium: mercury molar ratios, among tissues. Mercury and selenium levels were correlated in kidney and skin/scales. Mercury levels were highest in kidney, intermediate in muscle and liver, and lowest in brain and skin/scales; selenium levels were also highest in kidney, intermediate in liver, and were an order of magnitude lower in the white muscle and brain. Mercury levels in muscle, kidney and skin/scales were positively correlated with fish size (length). Selenium levels in muscle, kidney and liver were positively correlated with fish length, but in brain; selenium levels were negatively correlated with fish length. The selenium: mercury molar ratio was negatively correlated with fish length for white muscle, liver, kidney, and brain, particularly for fish over 50 cm in length, suggesting that older fish experience less protective advantages of selenium against mercury toxicity than smaller fish, and that consumers of bluefish similarly receive less advantage from eating larger fish. PMID:23202378

  20. Mercury and selenium in European catfish (Silurus glanis) from Northern Italian Rivers: can molar ratio be a predictive factor for mercury toxicity in a top predator?

    Science.gov (United States)

    Squadrone, S; Benedetto, A; Brizio, P; Prearo, M; Abete, M C

    2015-01-01

    The study of mercury and selenium bioaccumulation in fish is crucially important for evaluating the extent of contamination in freshwater environments, and the possible health risk posed for humans when the antagonistic interactions of these two elements are considered. Several factors affect the risk of mercury intake from fish consumption, including mercury levels, human consumption patterns, and sensitive populations (e.g., pregnant women, foetuses, young children and unknown genetic factors). The protective effects of selenium on mercury toxicity have been extensively publicised in recent years, particularly targeting fish consumers. In this study, mercury (Hg) and selenium (Se) concentrations were determined in the muscle of European catfish (Silurus glanis) collected from North Italian Rivers. Differences in mercury and selenium levels, as a function of size, gender and location were investigated. Hg was strongly related to length, gender and location, while Se levels are not dependent on fish size or location. The mean Se/Hg molar ratio was strongly affected by location, and significantly related to length and age. Selenium was in molar excess of mercury in all sites, with a rank order of mean Se/Hg molar ratio of the Parma River (2.55)>Po River (1.71)>Tanaro River (1.66)>Bormida River (1.36). However, in 37% of analyzed samples, Hg exceeded the maximum level set by 1881/2006/EC and 629/2008/EC in fish muscle. The molar ratio of Se/Hg was 0.5mg/kg), and therefore the mean molar ratio cannot be considered as a safety criterion in top predator fish. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis

    International Nuclear Information System (INIS)

    Alinat, Elodie; Delaunay, Nathalie; Archer, Xavier; Mallet, Jean-Maurice; Gareil, Pierre

    2015-01-01

    Highlights: • New insights into the nitrocellulose alkaline denitration mechanism. • Linear correlation for molar ratio of nitrite-to-nitrate ions and nitrogen content. • Capillary electrophoresis monitoring of nitrite and nitrate ions. • Applications to explosive and non-explosive nitrocellulose-containing samples. • Improved performances (including safety) over classical methods. - Abstract: A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (n = 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1 h for alkaline hydrolysis, 3 min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1 M sodium hydroxide for 1 h at 60 °C)

  2. A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Alinat, Elodie, E-mail: elodie.alinat@chimie-paristech.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); Delaunay, Nathalie, E-mail: nathalie.delaunay@espci.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); Archer, Xavier, E-mail: xavier.archer@interieur.gouv.fr [Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris (France); Mallet, Jean-Maurice, E-mail: jean-maurice.mallet@es.fr [École Normale Supérieure-PSL Research University, Département de Chimie, 24 rue Lhomond, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); CNRS, UMR 7203 LBM, F-75005 Paris (France); Gareil, Pierre, E-mail: pierre.gareil@chimie-paristech.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France)

    2015-04-09

    Highlights: • New insights into the nitrocellulose alkaline denitration mechanism. • Linear correlation for molar ratio of nitrite-to-nitrate ions and nitrogen content. • Capillary electrophoresis monitoring of nitrite and nitrate ions. • Applications to explosive and non-explosive nitrocellulose-containing samples. • Improved performances (including safety) over classical methods. - Abstract: A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (n = 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1 h for alkaline hydrolysis, 3 min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1 M sodium hydroxide for 1 h at 60 °C)

  3. Effect of Cu/In molar ratio on the microstructural and optical properties of microcrystalline CuInS2 prepared by solvothermal route

    International Nuclear Information System (INIS)

    Das, Kajari; Panda, Subhendu K.; Gorai, Soma; Mishra, Pratima; Chaudhuri, Subhadra

    2008-01-01

    Synthesis and characterization of CuInS 2 powder sample prepared by a simple and convenient solvothermal method is reported. The influence of the variation of Cu/In molar ratio from 0.69 to 1.25 on the particle morphology, crystal structure and optical properties of CuInS 2 samples was studied. The X-ray diffraction studies indicated that the samples were polycrystalline in nature. SEM images of the samples revealed that the copper-rich products were uniform microspheres with smooth surfaces, whereas microspheres formed by network of interconnected flakes were obtained for indium-rich products. The optical band gaps (E g ) of the products decreased from 1.60 to 1.43 eV with variation of Cu/In molar ratio. The variation of the Urbach tail width with Cu/In molar ratio indicated that the density of the defects is much higher for the indium-rich CuInS 2 , which was clearly revealed from Raman measurements

  4. Nutritional status and phytate:zinc and phytate x calcium:zinc dietary molar ratios of lacto-ovo vegetarian Trappist monks: 10 years later.

    Science.gov (United States)

    Harland, B F; Smith, S A; Howard, M P; Ellis, R; Smith, J C

    1988-12-01

    A nutrition assessment of 16 members of a community of lacto-ovo vegetarian Trappist monks was conducted in 1977. Plasma zinc was found to be low-normal, which was attributed primarily to high intakes of phytate-containing foods. Individual and group counseling were instituted over a 10-year period in an attempt to emphasize the importance of wise food selection within the constraints of lacto-ovo vegetarianism. In 1987, a more comprehensive nutrition assessment of 21 members of the same community was performed. Food composites were analyzed, and 3-day instead of 24-hour dietary records were kept. Intakes of phytate-containing foods had decreased from 4,569 to 972 mg/day; intake of dietary zinc had increased from 7.4 to 9.7 mg/day; and the phytate:zinc molar ratio had decreased from 67 to 14 for the years 1977 and 1987, respectively. An analyzed phytate:zinc molar ratio of 9.8 and an analyzed phytate x calcium:zinc molar ratio of 0.3 were representative of the 1987 community. Both were within normal ranges. Plasma zinc had risen to upper-normal levels. The 1987 nutrition assessment showed that it is possible to be adequately nourished with a lacto-ovo vegetarian diet provided one has proper knowledge of the phytate-containing foods and the methods for compensating with foods of greater mineral density (primarily zinc).

  5. Molar Pregnancy

    Science.gov (United States)

    ... weeks of pregnancy Ovarian cysts Anemia Overactive thyroid (hyperthyroidism) Causes A molar pregnancy is caused by an ... have this complication than a partial molar pregnancy. Prevention If you've had a molar pregnancy, talk ...

  6. Possible effects of insulin-like growth factor-I, IGF-binding protein-3 and IGF-1/IGFBP-3 molar ratio on mammographic density: a cross-sectional study.

    Science.gov (United States)

    Meggiorini, M L; Cipolla, V; Borgoni, G; Nofroni, I; Pala, A; de Felice, C

    2012-01-01

    The purpose of this study was to examine the possible effects of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio on mammographic density and assess whether this relationship was similar in subgroups of pre- and postmenopausal women. A group of 341 Italian women of childbearing age or naturally postmenopausal who had performed mammographic examination at the section of radiology of our department a maximum three months prior to recruitment were enrolled. A blood sample was drawn for determination of IGF-1, IGFBP-3 levels and IGF-1/IGFBP-3 molar ratio was calculated. On the basis of recent mammograms the women were divided into two groups: dense breast (DB) and non-dense breast (NDB). To assess the association between mammographic density and IGF-1, IGFBP-3 and Molar ratio Student's t-test was employed before and after stratified by menopausal status. The analysis of the relationship between mammographic density and plasma levels of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio showed that IGF-1 levels and molar ratio varied in the two groups resulting in higher mean values in the DB group whereas IGFBP-3 showed similar values in both groups (DB and NDB). After stratification of the study population by menopausal status, no association was found. Our study provides strong evidence of a crude association between breast density, and plasma levels of IGF-1 and molar ratio. IGF-1 and molar ratio might increase mammographic density and thus the risk of developing breast cancer.

  7. A study on the determination of Ca/P molar ratio in calcium-hydroxyapatite by alpha excited x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Mizumoto, Yoshihiko; Iwata, Shiro.

    1979-01-01

    Nondestructive powdery calcium-hydroxyapatite (HAp) target was prepared by electrodeposition method. The powdery HAp was deposited on the copper electrode plate of cathode in the electrodeposition solution such as ethyl alcohol, methyl alcohol, etc. The experiments were carried out as functions of different electrodeposition solution, ethyl alcohol concentration, distance between anode and cathode, electrodeposition time and HAp amount added in bath, and distribution of HAp on the copper electrode plate obtained from each experiment was investigated by alpha excited X-ray fluorescence analysis. Ca/P molar ratio of thin HAp target prepared with this method was determined by alpha excited X-ray fluorescence spectrometry. The nondestructive HAp targets of thickness in the range of 5 mu g/cm 2 to 10 mg/cm 2 were easily prepared with comparatively simple apparatus. The HAp on the copper electrode plate was uniform thickness over 15 x 20 mm copper plate within 5%. The Ca/P molar ratio of HAp was 1.64 +- 0.05, which agreed well with stoichiometric value of 1.67 in HAp within standard deviation. (author)

  8. MOLAR UPRIGHTING

    Directory of Open Access Journals (Sweden)

    Eka Erwansyah

    2006-04-01

    Full Text Available The mesial tipping of molar is frequently found in orthodontic cases. This molar malposition must be corrected since it may cause periodontal disorders, occlusal interferences, and temporomandibular joint dysfunction, and is often needed in planning a fixed bridge. This paper is a literature study to discuss about appliance designs, indication, and contraindications, and complication and treatment protocols of molar uprighting by fixed orthodontic appliances. By knowing the techniques of molar uprighting, the moments mentioned above can be avoided.

  9. Glycerol capped PbS/CdS core/shell nanoparticles at different molar ratio and its application in biosensors: An optical properties study

    Energy Technology Data Exchange (ETDEWEB)

    Das, D., E-mail: ddasphy014@gmail.com; Hussain, A. M. P. [Department of Physics, Cotton College, Guwahati, Assam, India- 781001 (India)

    2016-05-06

    Glycerol capped PbS/CdS core/shell type nanoparticles fabricated with two different molar ratios are characterized for study of structural and optical properties. The X-ray diffraction (XRD) pattern exhibits cubic phased polycrystalline nanocrystals. The calculated grain sizes from Williamson-Hall plot were found to be around 6 nm with increased strain. HRTEM investigation confirms the formation of core/shell nanostructures and the sizes of the particles were found to be around 7 nm which is in good agreement with the results of the W-H plot. An increase of band gap with the decrease in precursor concentration is confirmed from the blue shift in the absorption spectra and also from Tauc plot. A clear blue shifted intense emission is observed in the photoluminescence spectra with decrease in particle size. Intense luminescence from the core/shell nanostructure may be applied in bio labelling and biosensors.

  10. Formation of copper nanoparticles in mordenite s with variable SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios under redox treatments

    Energy Technology Data Exchange (ETDEWEB)

    Petranovskii, V.; Avalos, M. [UNAM, Centro de Nanociencias y Nanotecnologia, Km 107 Carretera Tijuana-Ensenada, 22800 Ensenada, Baja California (Mexico); Stoyanov, E. [University of California, Department of Chemistry, Riverside, 92521 California (United States); Gurin, V. [Belarusian State University, Research Institute for Physical Chemical Problems, Minsk 220080 (Belarus); Katada, N. [Tottori University, Department of Chemistry and Biotechnology, Tottori 680-8552 (Japan); Hernandez, M. A. [Benemerita Universidad Autonoma de Puebla, Departamento de Investigacion en Zeolitas, Ciudad Universitaria, Puebla (Mexico); Pestryakov, A. [Tomsk Polytechnic University, Tomsk 634050 (Russian Federation); Chavez R, F.; Zamorano U, R. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, Zacatenco, 07738 Mexico D. F. (Mexico); Portillo, R., E-mail: vitalii@cnyn.unam.mx [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Ciudad Universitaria, Puebla (Mexico)

    2013-05-01

    A series of protonated copper-containing mordenite s with different SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios (MR) in the range of 10{<=}MR{<=}206 was prepared by ion exchange in copper nitrate aqueous solution. The electron paramagnetic resonance of hydrated copper Mordenite s series testifies of several Cu{sup 2+} ion sites. Hydrogen reduction of copper ions incorporated into the mordenite s was shown to lead to different reduced copper species including small metallic particles inter alia. The structural properties and acidity of mordenite s were characterized. The optical appearance of the copper particles showed strong but nonmonotonic dependence on the MR value, in line with the variation in acidity of this series of mordenite s. Correlations between mordenite properties and the formation of different reduced copper species are discussed. (Author)

  11. Modelling Chemical Kinetics of Soybean Oil Transesterification Process for Biodiesel Production: An Analysis of Molar Ratio between Alcohol and Soybean Oil Temperature Changes on the Process Conversion Rate

    Directory of Open Access Journals (Sweden)

    Maicon Tait

    2006-12-01

    Full Text Available A mathematical model describing chemical kinetics of transesterification of soybean oil for biodiesel production has been developed. The model is based on the reverse mechanism of transesterification reactions and describes dynamics concentration changes of triglycerides, diglycerides, monoglycerides, biodiesel, and glycerol production. Reaction rate constants were written in the Arrhenius form. An analysis of key process variables such as temperature and molar ratio soybean oil- alcohol using response surface analysis was performed to achieve the maximum soybean conversion rate to biodiesel. The predictive power of the developed model was checked for the very wide range of operational conditions and parameters values by fitting different experimental results for homogeneous catalytic and non-catalytic processes published in the literature. A very good correlation between model simulations and experimental data was observed.

  12. Synthesis of geopolymer from spent FCC: Effect of SiO2/Al2O<3 and Na2O/SiO2 molar ratios

    Directory of Open Access Journals (Sweden)

    Trochez, J. J.

    2015-03-01

    Full Text Available This paper assesses the feasibility of using a spent fluid catalytic cracking catalyst (SFCC as precursor for the production of geopolymers. The mechanical and structural characterization of alkali-activated SFCC binders formulated with different overall (activator + solid precursor SiO2/Al2O3 and Na2O/SiO2 molar ratios are reported. Formation of an aluminosilicate ‘geopolymer’ gel is observed under all conditions of activation used, along with formation of zeolites. Increased SiO2/Al2O3 induces the formation of geopolymers with reduced mechanical strength, for all the Na2O/SiO2 ratios assessed, which is associated with excess silicate species supplied by the activator. This is least significant at increased alkalinity conditions (higher Na2O/SiO2 ratios, as larger extents of reaction of the spent catalyst are achieved. SiO2/Al2O3 and Na2O/SiO2 ratios of 2.4 and 0.25, respectively, promote the highest compressive strength (67 MPa. This study elucidates the great potential of using SFCC as precursor to produce sustainable ceramic-like materials via alkali-activation.Este artículo estudia la factibilidad de usar un catalizador gastado del proceso de craqueo (SFCC para la producción de geopolímeros. Se evalúan las características mecánicas y estructurales de los geopolímeros producidos con diferentes relaciones molares (activador + precursor solido de SiO2/Al2O3 y Na2O/SiO2. La formación de un gel geopolimérico de tipo aluminosilicato se observa a las diferentes condiciones evaluadas, así como la formación de zeolitas. Un incremento en la relación SiO2/Al2O3 genera geopolímeros de baja resistencia mecánica, a las diferentes relaciones molares Na2O/SiO2 evaluadas, como consecuencia del exceso de especies silicato provenientes del activador. Este efecto es menos significativo al incrementar las condiciones de alcalinidad (mayores relaciones Na2O/SiO2, ya que un mayor grado de reacción del catalizador gastado es alcanzado. Las

  13. Circulating levels of IGF-1, IGFBP-3, and IGF-1/IGFBP-3 molar ratio and colorectal adenomas: A meta-analysis.

    Science.gov (United States)

    Yoon, Yeong Sook; Keum, NaNa; Zhang, Xuehong; Cho, Eunyoung; Giovannucci, Edward L

    2015-12-01

    Insulin-like growth factor-1(IGF-1) promotes cell proliferation and inhibits apoptosis, and is thereby implicated in carcinogenesis. Insulin-like growth factor binding protein-3 (IGFBP-3) may antagonize IGF-1 action, leading to inhibition of the potential tumorigenicity of IGF-1. We conducted this meta-analysis to estimate the association between IGF-1, IGFBP-3 and IGF-1/IGFBP-3 ratio and the risk of colorectal adenomas (CRAs). Further, we investigated whether this association was different between occurrent and recurrent CRA, by adjustment for obesity, and by advanced CRA. Pubmed and Embase were searched up to April, 2015 to identify relevant observational studies and summary odds ratio (OR) and the corresponding 95% confidence interval (95% CI) was estimated using a random-effects model. A total of 12 studies (11 studies including 3038 cases for IGF-1, 12 studies including 3208 cases for IGFBP-3, and 7 studies including 1867 cases for IGF-1/IGFBP-3 ratio) were included in this meta-analysis. The summary ORs of occurrent CRA for the highest versus lowest category of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 ratio were 1.13 (95% CI: 0.95-1.34), 0.99 (0.84-1.16), and 1.05 (0.86-1.29), respectively. Higher IGF-1 and IGF-1/IGFBP-3 ratio were significantly associated with decreased risk of recurrent CRA (OR for IGF-1=0.60 [95% CI: 0.42-0.85]; IGF-1/IGFBP-3 ratio=0.65 [0.44-0.96]). A stratified analysis by advancement of occurrent CRA produced a significant summary OR of IGF-1 for advanced CRA (OR=2.21 [1.08-4.52]) but not for non-advanced CRA (OR=0.89 [0.55-1.45]). We did not find significant publication bias or heterogeneity. Circulating levels of IGF-1, IGFBP-3 and their molar ratio were not associated with the risk of occurrence of CRA, but IGF-1 was associated with the increased risk for occurrence of advanced CRA. Copyright © 2015. Published by Elsevier Ltd.

  14. Exploring the possibility to store the mixed oxygen-hydrogen cluster in clathrate hydrate in molar ratio 1:2 (O2+2H2).

    Science.gov (United States)

    Qin, Yan; Du, Qi-Shi; Xie, Neng-Zhong; Li, Jian-Xiu; Huang, Ri-Bo

    2017-05-01

    An interesting possibility is explored: storing the mixture of oxygen and hydrogen in clathrate hydrate in molar ratio 1:2. The interaction energies between oxygen, hydrogen, and clathrate hydrate are calculated using high level quantum chemical methods. The useful conclusion points from this study are summarized as follows. (1) The interaction energies of oxygen-hydrogen mixed cluster are larger than the energies of pure hydrogen molecular cluster. (2) The affinity of oxygen molecules with water molecules is larger than that of the hydrogen molecules with water molecules. (3) The dimension of O 2 -2H 2 interaction structure is smaller than the dimension of CO 2 -2H 2 interaction structure. (4) The escaping energy of oxygen molecules from the hydrate cell is larger than that of the hydrogen molecules. (5) The high affinity of the oxygen molecules with both the water molecules and the hydrogen molecules may promote the stability of oxygen-hydrogen mixture in the clathrate hydrate. Therefore it is possible to store the mixed (O 2 +2H 2 ) cluster in clathrate hydrate. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Barium recovery by crystallization in a fluidized-bed reactor: effects of pH, Ba/P molar ratio and seed.

    Science.gov (United States)

    Su, Chia-Chi; Reano, Resmond L; Dalida, Maria Lourdes P; Lu, Ming-Chun

    2014-06-01

    The effects of process conditions, including upward velocity inside the column, the amount of added seed and seed size, the pH value of the precipitant or the phosphate stream and the Ba/P molar ratio in a fluidized-bed reactor (FBR) were studied with a view to producing BaHPO₄ crystals of significant size and maximize the removal of barium. XRD were used to identify the products that were collected from the FBR. Experimental results show that an upward velocity of 48 cmmin(-1) produced the largest BaHPO₄ crystals with a size of around 0.84-1.0mm. The addition of seed crystals has no effect on barium removal. The use of a seed of a size in the ranges unseededbarium was removed at pH 8.4-8.6 and [Ba]/[P]=1.0. The XRD results show that a significant amount of barium phosphate (Ba₃(PO₄)₂) was obtained at pH 11. The compounds BaHPO₄ and BaO were present at a pH of below 10. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Evaluation of NO2 predictions by the plume volume molar ratio method (PVMRM) and ozone limiting method (OLM) in AERMOD using new field observations.

    Science.gov (United States)

    Hendrick, Elizabeth M; Tino, Vincent R; Hanna, Steven R; Egan, Bruce A

    2013-07-01

    The U.S. Environmental Protection Agency (EPA) plume volume molar ratio method (PVMRM) and the ozone limiting method (OLM) are in the AERMOD model to predict the 1-hr average NO2/NO(x) concentration ratio. These ratios are multiplied by the AERMOD predicted NO(x) concentration to predict the 1-hr average NO2 concentration. This paper first briefly reviews PVMRM and OLM and points out some scientific parameterizations that could be improved (such as specification of relative dispersion coefficients) and then discusses an evaluation of the PVMRM and OLM methods as implemented in AERMOD using a new data set. While AERMOD has undergone many model evaluation studies in its default mode, PVMRM and OLM are nondefault options, and to date only three NO2 field data sets have been used in their evaluations. Here AERMOD/PVMRM and AERMOD/OLM codes are evaluated with a new data set from a northern Alaskan village with a small power plant. Hourly pollutant concentrations (NO, NO2, ozone) as well as meteorological variables were measured at a single monitor 500 m from the plant. Power plant operating parameters and emissions were calculated based on hourly operator logs. Hourly observations covering 1 yr were considered, but the evaluations only used hours when the wind was in a 60 degrees sector including the monitor and when concentrations were above a threshold. PVMRM is found to have little bias in predictions of the C(NO2)/C(NO(x)) ratio, which mostly ranged from 0.2 to 0.4 at this site. OLM overpredicted the ratio. AERMOD overpredicts the maximum NO(x) concentration but has an underprediction bias for lower concentrations. AERMOD/PVMRM overpredicts the maximum C(NO2) by about 50%, while AERMOD/OLM overpredicts by a factor of 2. For 381 hours evaluated, there is a relative mean bias in C(NO2) predictions of near zero for AERMOD/PVMRM, while the relative mean bias reflects a factor of 2 overprediction for AERMOD/OLM. This study was initiated because the new stringent 1-hr NO2

  17. Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Alnoor, Hatim, E-mail: hatim.alnoor@liu.se; Iandolo, Donata; Willander, Magnus; Nur, Omer [Department of Science and Technology (ITN), Linköping University, SE-601 74 Norrköping (Sweden); Pozina, Galia; Khranovskyy, Volodymyr; Liu, Xianjie [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-583 81 Linköping (Sweden)

    2016-04-28

    Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5 M exhibit stronger yellow emission (∼575 nm) compared to those based on 1:1 and 1:3 M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination.

  18. Time-dependent fracture probability of bilayer, lithium-disilicate-based glass-ceramic molar crowns as a function of core/veneer thickness ratio and load orientation

    Science.gov (United States)

    Anusavice, Kenneth J.; Jadaan, Osama M.; Esquivel–Upshaw, Josephine

    2013-01-01

    Recent reports on bilayer ceramic crown prostheses suggest that fractures of the veneering ceramic represent the most common reason for prosthesis failure. Objective The aims of this study were to test the hypotheses that: (1) an increase in core ceramic/veneer ceramic thickness ratio for a crown thickness of 1.6 mm reduces the time-dependent fracture probability (Pf) of bilayer crowns with a lithium-disilicate-based glass-ceramic core, and (2) oblique loading, within the central fossa, increases Pf for 1.6-mm-thick crowns compared with vertical loading. Materials and methods Time-dependent fracture probabilities were calculated for 1.6-mm-thick, veneered lithium-disilicate-based glass-ceramic molar crowns as a function of core/veneer thickness ratio and load orientation in the central fossa area. Time-dependent fracture probability analyses were computed by CARES/Life software and finite element analysis, using dynamic fatigue strength data for monolithic discs of a lithium-disilicate glass-ceramic core (Empress 2), and ceramic veneer (Empress 2 Veneer Ceramic). Results Predicted fracture probabilities (Pf) for centrally-loaded 1,6-mm-thick bilayer crowns over periods of 1, 5, and 10 years are 1.2%, 2.7%, and 3.5%, respectively, for a core/veneer thickness ratio of 1.0 (0.8 mm/0.8 mm), and 2.5%, 5.1%, and 7.0%, respectively, for a core/veneer thickness ratio of 0.33 (0.4 mm/1.2 mm). Conclusion CARES/Life results support the proposed crown design and load orientation hypotheses. Significance The application of dynamic fatigue data, finite element stress analysis, and CARES/Life analysis represent an optimal approach to optimize fixed dental prosthesis designs produced from dental ceramics and to predict time-dependent fracture probabilities of ceramic-based fixed dental prostheses that can minimize the risk for clinical failures. PMID:24060349

  19. Time-dependent fracture probability of bilayer, lithium-disilicate-based, glass-ceramic, molar crowns as a function of core/veneer thickness ratio and load orientation.

    Science.gov (United States)

    Anusavice, Kenneth J; Jadaan, Osama M; Esquivel-Upshaw, Josephine F

    2013-11-01

    Recent reports on bilayer ceramic crown prostheses suggest that fractures of the veneering ceramic represent the most common reason for prosthesis failure. The aims of this study were to test the hypotheses that: (1) an increase in core ceramic/veneer ceramic thickness ratio for a crown thickness of 1.6mm reduces the time-dependent fracture probability (Pf) of bilayer crowns with a lithium-disilicate-based glass-ceramic core, and (2) oblique loading, within the central fossa, increases Pf for 1.6-mm-thick crowns compared with vertical loading. Time-dependent fracture probabilities were calculated for 1.6-mm-thick, veneered lithium-disilicate-based glass-ceramic molar crowns as a function of core/veneer thickness ratio and load orientation in the central fossa area. Time-dependent fracture probability analyses were computed by CARES/Life software and finite element analysis, using dynamic fatigue strength data for monolithic discs of a lithium-disilicate glass-ceramic core (Empress 2), and ceramic veneer (Empress 2 Veneer Ceramic). Predicted fracture probabilities (Pf) for centrally loaded 1.6-mm-thick bilayer crowns over periods of 1, 5, and 10 years are 1.2%, 2.7%, and 3.5%, respectively, for a core/veneer thickness ratio of 1.0 (0.8mm/0.8mm), and 2.5%, 5.1%, and 7.0%, respectively, for a core/veneer thickness ratio of 0.33 (0.4mm/1.2mm). CARES/Life results support the proposed crown design and load orientation hypotheses. The application of dynamic fatigue data, finite element stress analysis, and CARES/Life analysis represent an optimal approach to optimize fixed dental prosthesis designs produced from dental ceramics and to predict time-dependent fracture probabilities of ceramic-based fixed dental prostheses that can minimize the risk for clinical failures. Copyright © 2013 Academy of Dental Materials. All rights reserved.

  20. The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shaharun, Salina, E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Taha, Mohd F., E-mail: faisalt@petronas.com.my [Department of Fundamental and Applied Science, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Mohamad, Dasmawati, E-mail: dasmawati@kck.usm.my [School of Dental Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2014-10-24

    Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.6–59.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  1. Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4 Nanocrystal as Calcined Products of Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Abdullah Ahmed Ali Ahmed

    2014-01-01

    Full Text Available The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH nanostructure at different Zn2+/Fe3+ molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD. LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4. The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4 and 43.3 nm for ZnO. The photocatalytic activity of the calcination products was investigated using ultraviolet-visible-near infrared (UV-VIS-NIR diffuse reflectance spectroscopy. The magnetic properties of calcined LDHs were investigated using a vibrating sample magnetometer (VSM. The calcined samples showed a paramagnetic behavior for all Zn2+/Fe3+ molar ratios. The effect of molar ratio on magnetic susceptibility of the calcined samples was also studied.

  2. Influência do agente de cloração do catalisador à base de veodímio e da razão molar Cl: Nd na polimerização do butadieno Influence of the chlorinating agent of neodymium based catalysts and Cl: Nd molar ratio on butadiene polymerization

    Directory of Open Access Journals (Sweden)

    Cintia N. Ferreira

    2009-06-01

    Full Text Available Neste trabalho foi utilizado um sistema catalítico composto por hidreto de diisobutilalumínio (DIBAH, versatato de neodímio (NdV e um agente de cloração para avaliar a influência da fonte de cloro e da razão molar Cl:Nd nas características da reação de polimerização (conversão e constante de velocidade de propagação e do polibutadieno (massa molecular e microestrutura. Os agentes de cloração estudados foram cloreto de t-butila (t-BuCl, sesquicloreto de etilalumínio (EASC e cloreto de dietilalumínio (DEAC. As razões molares Cl:Nd utilizadas foram: 1:1, 3:1 e 5:1 para o t-BuCl; 0,5:1, 1:1 e 3:1 para o EASC e 1:1, 1,5:1, 3:1 e 5:1 para o DEAC. Foi observada a existência, para cada agente de cloração, de um valor ótimo de razão molar Cl:Nd para o qual a conversão foi máxima. O DEAC apresentou uma maior conversão em relação aos outros agentes de cloração; em contrapartida, o t-BuCl produziu polibutadienos com maior teor de unidades 1,4-cis e maior massa molecular (n e wIn this work catalyst systems consisting of diisobutylaluminium hydride (DIBAH, neodymium versatate (NdV and a chlorinating agent were employed to study the influence of the chloride source and Cl:Nd molar ratio on 1,3-butadiene polymerization and polybutadiene's characteristics (molecular weight and microstructure. The chloride sources studied were t-butyl chloride, ethylaluminium sesquichloride (EASC and diethylaluminium chloride (DEAC. The Cl:Nd molar ratios used were 1:1, 3:1 e 5:1 for t-butyl chloride; 0.5:1, 1:1 and 3:1 for EASC and 1:1, 1.5:1, 3:1 and 5:1 for DEAC. A maximum value of Cl:Nd molar ratio exists. Moreover, DEAC showed to be more reactive than EASC and t-BuCl but t-BuCl produced higher molecular weight and cis-1,4 units contents.

  3. Periodicity in the BrO/SO2 molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

    Science.gov (United States)

    Dinger, Florian; Bobrowski, Nicole; Warnach, Simon; Bredemeyer, Stefan; Hidalgo, Silvana; Arellano, Santiago; Galle, Bo; Platt, Ulrich; Wagner, Thomas

    2018-03-01

    We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change) gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador) for BrO/SO2 molar ratios. The BrO/SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua) suggest a possible link between a drop in BrO/SO2 and a future explosion. In addition, the observed relatively high BrO/SO2 molar ratios after December 2015 imply that bromine degassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on volcanic gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO/SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO/SO2 molar ratios with the north-south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO/SO2 molar ratios and the relative humidity in the local

  4. Periodicity in the BrO∕SO2 molar ratios in the volcanic gas plume of Cotopaxi and its correlation with the Earth tides during the eruption in 2015

    Directory of Open Access Journals (Sweden)

    F. Dinger

    2018-03-01

    Full Text Available We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador for BrO∕SO2 molar ratios. The BrO∕SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua suggest a possible link between a drop in BrO∕SO2 and a future explosion. In addition, the observed relatively high BrO∕SO2 molar ratios after December 2015 imply that bromine degassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on volcanic gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO∕SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO∕SO2 molar ratios with the north–south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO∕SO2 molar

  5. Theoretical insight into the binding energy and detonation performance of ε-, γ-, β-CL-20 cocrystals with β-HMX, FOX-7, and DMF in different molar ratios, as well as electrostatic potential.

    Science.gov (United States)

    Feng, Rui-Zhi; Zhang, Shu-Hai; Ren, Fu-de; Gou, Rui-Jun; Gao, Li

    2016-06-01

    Molecular dynamics method was employed to study the binding energies on the selected crystal planes of the ε-, γ-, β-conformation 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (ε-, γ-, β-CL-20) cocrystal explosives with 1,1-diamino-2,2-dinitroethylene (FOX-7), 1,3,5,7-tetranitro- 1,3,5,7-tetrazacyclooctane with β-conformation (β-HMX) and N,N-dimethylformamide (DMF) in different molar ratios. The oxygen balance, density, detonation velocity, detonation pressure, and surface electrostatic potential were analyzed. The results indicate that the binding energies E b (*) and stabilities are in the order of 1:1 > 2:1 > 3:1 > 5:1 > 8:1 (CL-20:FOX-7/β-HMX/DMF). The values of E b (*) and stabilities of the energetic-nonenergetic CL-20/DMF cocrystals are far larger than those of the energetic-energetic CL-20/FOX-7 and CL-20/β-HMX, and those of CL-20/β-HMX are the smallest. For CL-20/FOX-7 and CL-20/β-HMX, the largest E b (*) appears in the cocrystals with the 1:1, 1:2 or 1:3 molar ratio, and the stabilities of the cocrystals with the excess ratio of CL-20 are weaker than those in the cocrystals with the excess ratio of FOX-7 or β-HMX. In CL-20/FOX-7, CL-20 prefers adopting the γ-form, and ε-CL-20 is the preference in CL-20/β-HMX, and ε-CL-20 and β-CL-20 can be found in CL-20/DMF. The CL-20/FOX-7 and CL-20/β-HMX cocrystals with low molar ratios can meet the requirements of low sensitive high energetic materials. Surface electrostatic potential reveals the nature of the sensitivity change upon the cocrystal formation. Graphical Abstract MD method was employed to study the binding energies on the selected crystal planes in the ε-, γ-, β-CL-20 cocrystals with FOX-7, β-HMX and DMF in different molar ratios. Surface electrostatic potential reveals the nature of the sensitivity change in cocrystals.

  6. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2015-05-01

    Full Text Available This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA using LUSI (Sidoarjo mud and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  7. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Science.gov (United States)

    Abdul Razak, Rafiza; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Hardjito, Djwantoro; Yahya, Zarina

    2015-01-01

    This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced. PMID:26006238

  8. Effect of molar ratios of MgO/Al{sub 2}O{sub 3} on the sintering behavior and thermal shock resistance of MgOAl{sub 2}O{sub 3}SiO{sub 2} composite ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Dong, E-mail: 1078155409@qq.com [School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051 (China); Luo, Xudong, E-mail: luoxudongs@aliyun.com [School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051 (China); Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Guodong [School of High Temperature Materials and Magnesium Resource Engineering, University of Science and Technology Liaoning, Anshan 114051 (China); Xie, Zhipeng [Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-01-01

    In order to determine the relationship between the property of MgOAl{sub 2}O{sub 3}SiO{sub 2} composite ceramics and molar ratios of MgO/Al{sub 2}O{sub 3}, especially the sintering behavior and thermal shock resistance, the MgOAl{sub 2}O{sub 3}SiO{sub 2} composite ceramics were fabricated with micro-size MgO, Al{sub 2}O{sub 3} powder and nano-size SiO{sub 2} as main raw materials. The sample was characterized by phase analysis, densification and thermal shock times. Moreover, field emission scanning electron microscope was also conducted to study microstructure of the samples before and after thermal shock. Effect of different molar ratios of MgO/Al{sub 2}O{sub 3} on the sintering behavior and thermal shock resistance of composite ceramics were investigated. The results showed that the sample possess better sintering behavior and thermal shock resistance with the molar ratio of MgO/Al{sub 2}O{sub 3} equal to 2/1. Grains of periclase and spinel were directly bonded together, resulting in a dense and compact microstructure, and the bulk density of obtained sample reached 3.4 g/cm{sup 3}. The microstructure of sample after thermal shock revealed that the crack propagation path was deflected and bifurcated, the main-crack propagation was restricted and more fracture energy was consumed, the thermal shock resistance of composite ceramics was greatly improved. - Highlights: • Effect of MgO/Al{sub 2}O{sub 3} on the composite ceramic was firstly researched with 1 mol% SiO{sub 2}. • Microcracks for a short distance by interlinking can eliminate the crack propagation. • The composite ceramic have optimal synthetic property with MgO/Al{sub 2}O{sub 3} was 2/1.

  9. The effect of CaO/SiO2 molar ratio of CaO-Al2O3-SiO2 glasses on their structure and reactivity in alkali activated system.

    Science.gov (United States)

    Kucharczyk, Sylwia; Sitarz, Maciej; Zajac, Maciej; Deja, Jan

    2018-04-05

    The influence of CaO/SiO 2 molar ratio of calcium aluminosilicate glasses on resulting structure and reactivity was investigated. Chemical compositions of glasses were chosen to mimic the composition of the fly ash and slag amorphous phase. Understanding the reactivity of these materials is of high importance allowing further development of the composite cements to limit the environmental footprint of cement industry. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were employed to examine the structure of glasses. Reactivity of the glasses was analyzed on paste samples after 1, 2, 7, 28 and 90days of curing by means of thermogravimetry (TGA), X-ray diffraction (XRD) and FTIR. Spectroscopic results emphasize dependence of the structure on the chemical composition of the glasses. The higher CaO/SiO 2 the more depolymerized the glass network is, though there is no direct correlation with the reactivity. Significant differences in reactivity is observed primarily between the glasses of peraluminous (CaO/Al 2 O 3 1). Amongst the pastes made of glasses of percalcic region a higher degree of reaction at later ages is observed for the paste containing glass of lower CaO/SiO 2 molar ratio. This is due to both degree of depolimerization and the nature of these glasses (pozzolanic and hydraulic materials). No difference of degree of reaction has been observed within the glasses of CaO/SiO 2 lower than 1. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. The effect of CaO/SiO2 molar ratio of CaO-Al2O3-SiO2 glasses on their structure and reactivity in alkali activated system

    Science.gov (United States)

    Kucharczyk, Sylwia; Sitarz, Maciej; Zajac, Maciej; Deja, Jan

    2018-04-01

    The influence of CaO/SiO2 molar ratio of calcium aluminosilicate glasses on resulting structure and reactivity was investigated. Chemical compositions of glasses were chosen to mimic the composition of the fly ash and slag amorphous phase. Understanding the reactivity of these materials is of high importance allowing further development of the composite cements to limit the environmental footprint of cement industry. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were employed to examine the structure of glasses. Reactivity of the glasses was analyzed on paste samples after 1, 2, 7, 28 and 90 days of curing by means of thermogravimetry (TGA), X-ray diffraction (XRD) and FTIR. Spectroscopic results emphasize dependence of the structure on the chemical composition of the glasses. The higher CaO/SiO2 the more depolymerized the glass network is, though there is no direct correlation with the reactivity. Significant differences in reactivity is observed primarily between the glasses of peraluminous (CaO/Al2O3 1). Amongst the pastes made of glasses of percalcic region a higher degree of reaction at later ages is observed for the paste containing glass of lower CaO/SiO2 molar ratio. This is due to both degree of depolimerization and the nature of these glasses (pozzolanic and hydraulic materials). No difference of degree of reaction has been observed within the glasses of CaO/SiO2 lower than 1.

  11. Deciduous molar hypomineralization and molar incisor hypomineralization

    NARCIS (Netherlands)

    Elfrink, M.E.C.; ten Cate, J.M.; Jaddoe, V.W.V.; Hofman, A.; Moll, H.A.; Veerkamp, J.S.J.

    2012-01-01

    This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop

  12. Effects of H2O/Na2O molar ratio on the strength of alkaline activated ground blast furnace slag-ultrafine palm oil fuel ash based concrete

    International Nuclear Information System (INIS)

    Yusuf, Moruf Olalekan; Megat Johari, Megat Azmi; Ahmad, Zainal Arifin; Maslehuddin, Mohammed

    2014-01-01

    Highlights: • Effects of H 2 O/Na 2 O on GBFS-POFA alkaline activated concrete are investigated. • High H 2 O/Na 2 O contents enhance dissolutions/workability at the expense of strength. • Lower H 2 O/Na 2 O molar ratios aid compressive strength of the products. • Increase in H 2 O/Na 2 O favours the reactivity of Ca and the products molecular bonds. • Low H 2 O/Na 2 O positively affects the microstructural density of the products. - Abstract: Effects of H 2 O/Na 2 O molar ratios (MRs) on the developed alkaline activated pozzolanic solid wastes (PMs)-ultrafine palm oil fuel ash (UPOFA) and ground blast furnace slag (GBFS)-were studied by using the constant mass of combined activators (10 M NaOH aq + Na 2 SiO 3aq of silica-modulus (Ms = SiO 2 /Na 2 O) of 3.3).The free water content (FWC) expressed as FWC/(PMs) varied from 0.02 to 0.1 by mass while the total H 2 O/Na 2 O MRs ranged from 18.9 to 23.1 The findings revealed that increase in H 2 O/Na 2 O MRs negatively affects the strength but positively impact the mixture workability (consistency). The microstructural morphology examination using Scanning Electron Microscope coupled with Energy dispersive spectroscopy (SEM + EDS) reveals the contribution of H 2 O/Na 2 O MRs to the product nature, compactness, and the reactivity of Ca 2+ and Al 3+ while Fourier transform infra-red (FTIR) spectroscopy indicates that H 2 O/Na 2 O ratios contributed to the product amorphousity and carbonation process but sparingly affected its formed polymerized structural units (SiQ n (mAl), n = 2 and 3)

  13. Dependences of molar volumes in solids, partial molal and hydrated ionic volumes of alkali halides on covalent and ionic radii and the golden ratio

    Czech Academy of Sciences Publication Activity Database

    Heyrovská, Raji

    2007-01-01

    Roč. 436, č. 1-3 (2007), s. 287-293 ISSN 0009-2614 R&D Projects: GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040702 Keywords : alkali halides * ionic hydration * golden ratio Subject RIV: BO - Biophysics Impact factor: 2.207, year: 2007

  14. Chemometric study of the effects of PtRu:BH4-molar ratio and solvent used in the preparation of PtRu/C electrocatalysts for for direct methanol fuel cell anodes

    Energy Technology Data Exchange (ETDEWEB)

    Polanco, N.S.O.; Neto, A.O.; Spinace, E.V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Tusi, M.M. [Universidade Regional Integrada do Alto Uruguai e das Missoes (URI), Santiago, RS (Brazil); Brandalise, M. [Instituto Federal Fluminense (IFF), Campos dos Goyracazes, RJ (Brazil)

    2014-07-01

    PtRu/C electrocatalysts were prepared by borohydride reduction method and a chemometric study was performed to evaluate the influence of the solvent (water and isopropyl alcohol) and amount of reducing agent (PtRu:BH4- molar ratios of 5 and 15) in maximum power density. In borohydride reduction method, a solution containing sodium hydroxide and sodium borohydride (NaBH4) is added to a mixture containing water, isopropyl alcohol, metallic precursors and the carbon support Vulcan XC72. The obtained materials were characterized by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Membrane Electrode Assemblies (MEA's) were produced and tests in single direct methanol fuel cells were performed. The amount of sodium borohydride used in the reduction showed more influence on the maximum power density than the change of solvent of the reaction. (author)

  15. Effect of different processes and Ti/Zn molar ratios on the structure, morphology, and enhanced photoelectrochemical and photocatalytic performance of Ti3+ self-doped titanium-zinc hybrid oxides

    Science.gov (United States)

    Fu, Rongrong; Wang, Qingyao; Gao, Shanmin; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Lu, Jun

    2015-07-01

    Ti3+ self-doped titanium-zinc hybrid oxides with different phase compositions and morphologies were successfully synthesized using Zn powder as the reductant and Zn source by a chemical-reduction precipitation method with subsequent thermal treatment. The fabricated Ti3+ self-doped TiO2(A)/TiO2(R), TiO2(A)/TiO2(R)/ZnTiO3, and TiO2(A)/ZnO heterojunctions were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The effects of various Ti/Zn molar ratios and preparation processes on the structural, morphological, optical, photocurrent and photocatalytic properties of the resultant samples were investigated systematically. Results reveal that Ti3+ self-doping enhances the photoabsorption capability of titanium-zinc hybrid oxides in the visible-light region. Moreover, different processes and Ti/Zn molar ratios play great influences on the structure, morphology, optical, photocurrent and photocatalytic properties of the final products. Ti3+ self-doped titanium-zinc hybrid oxides exhibit excellent photocurrent and photocatalytic activity than pure TiO2 and ZnTiO3 under visible-light irradiation (λ ≥ 400 nm). The most active Ti3+ self-doped titanium-zinc hybrid oxides photoanode presents significantly improved water splitting performance. The synergistic effect between the Ti3+ self-doped and heterojunctions is responsible for the enhanced performance of these materials.

  16. Influence of the Ti concentration and of the Ti:Mo molar ratio, in the efficiency of the 99 Mo - 99m Tc generator, at basis of gels of titanium molybdates

    International Nuclear Information System (INIS)

    Cortes R, O.; Monroy G, F.; Martinez C, T.

    2003-01-01

    The 99m Tc, continues being the radionuclide more used in nuclear medicine to world scale. The production of this radioisotope, is carried out by means of generators 99 Mo/ 99m Tc that get ready commercially with 99 Mo of high specific activity, adsorbed in alumina (2 mg 99 Mo/g alumina) and that they are elutriated every 23 hours. In an alternative way, it is intended to use gels of titanium molybdates, as matrices of this generators. The gels are synthesized starting from solutions of ammonium molybdates and of titanium tetrachloride in aqueous media. These gels allow to incorporate until 25% of molybdenum in their structure, being been able to use 99 Mo of low specific activity that can be obtained starting from the reaction 98 Mo (n, γ) 99 Mo. With the object of producing generators of medium activity, with the base of gels of titanium molybdates, intends in this work, to study the influence of two synthesis parameters of these gels: the concentration of the titanium solutions and the molar ratio Ti: Mo. The decrease of the concentration of the titanium solution, used during the synthesis of the gels, is converted in an efficiency decrease and radionuclide purity of the generators, as well as an increment so much of the volume of elutriation, as of the pH of the elutriates. The gels that contain an major number of titanium moles, regarding the molybdenum moles, present a greater radionuclide purity, but they diminish their efficiency. The best characteristics for the gels synthesis of titanium molybdates are: a molar ratio 1:1 for Ti and Mo, and to use solutions of titanium whose concentration is near at 1 M. (Author)

  17. Effect of the Molar Ratio of B2O3 to Bi2O3 in Al Paste with Bi2O3-B2O3-ZnO Glass on Screen Printed Contact Formation and Si Solar Cell Performance

    Science.gov (United States)

    Kim, Bit-Na; Kim, Hyeong Jun; Chang, Hyo Sik; Hong, Hyun Seon; Ryu, Sung-Soo; Lee, Heon

    2013-10-01

    In this study, eco-friendly Pb-free Bi2O3-B2O3-ZnO glass frits were chosen as an inorganic additive for the Al paste used in Si solar cells. The effects of the molar ratio of Bi2O3 to B2O3 in the glass composition on the electrical resistance of the Al electrode and on the cell performance were investigated. The results showed that as the molar ratio of Bi2O3 to B2O3 increased, the glass transition temperature and softening temperature decreased because of the reduced glass viscosity. In Al screen-printed Si solar cells, as the molar ratio of Bi2O3 to B2O3 increased, the sheet electrical resistance of the Al electrode decreased and the cell efficiency increased. The uniformity and thickness of the back-surface field was significantly influenced by the glass composition.

  18. Effect of [Al] and [In] molar ratio in solutions on the growth and microstructure of electrodeposition Cu(In,Al)Se{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuo-Chan; Liu, Chien-Lin; Hung, Pin-Kun [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701, Taiwan (China); Houng, Mau-Phon, E-mail: mphoung@eembox.ncku.edu.tw [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701, Taiwan (China)

    2013-05-15

    In this paper, the cyclic voltammetric studies were used to realize the element's reduction potential and chemical reaction mechanism for presuming the formation routes of quaternary Cu(In,Al)Se{sub 2} crystals. Thereafter, the prior adjustment of deposited potential from −0.6 V to −1.0 V can be identified a suitable potential as co-electrodeposition. The material characteristics of Cu(In,Al)Se{sub 2} films are dominated by the percentage of aluminum content. Thus, the influence of aluminum and indium concentrations in solutions on the percentage composition, surface morphology, structural and crystal properties, and optical energy band gap of Cu(In,Al)Se{sub 2} films were investigated. Energy dispersive X-ray spectroscopy (EDS) indicated that the ratio of Al to (Al + In) in Cu(In,Al)Se{sub 2} films varied from 0.21 to 0.42 when adjusting aluminum and indium concentrations in solutions. Scanning electron microscopy (SEM) shows that the surface morphology changed from round-like structures into cauliflower-like structures and became rough when the aluminum concentration increased and indium concentration decreased in solutions. X-ray diffraction (XRD) patterns revealed three preferred growth orientations along the (1 1 2), (2 0 4/2 2 0), and (1 1 6/3 1 2) planes for all species. The (αhυ){sup 2} versus hυ plots (UV–Visible) shows that the optical energy band gap of the Cu(In,Al)Se{sub 2} films can be successfully controlled from 1.17 eV to 1.48 eV by adjusting the aluminum and indium concentrations. Furthermore, the shift of the (1 1 2) peak in the XRD patterns and variation of optical band gap are evidence that the incorporation of aluminum atoms into the crystallitic CuInSe{sub 2} forms Cu(In,Al)Se{sub 2} crystals.

  19. [Hyperthyroidism in molar pregnancy].

    Science.gov (United States)

    Boufettal, H; Mahdoui, S; Noun, M; Hermas, S; Samouh, N

    2014-03-01

    Hyperthyroidism is a rare complication of molar pregnancy. We report a 39-year-old woman who presented a thyrotoxic syndrome accompanying a molar pregnancy. Serum thyroid hormones were elevated and returned to normal level after uterine evacuation of a molar pregnancy. The authors detail the role of thyroid stimulating property of human gonadotropin chorionic hormone and its structural changes during the gestational trophoblastic diseases. These changes give the latter the thyroid stimulating properties and signs of hyperthyroidism. Molar pregnancy may be a cause of hyperthyroidism. The diagnosis of molar pregnancy should be a mention to thyrotoxicosique syndrome in a woman of childbearing age. Copyright © 2013. Published by Elsevier SAS.

  20. Deposition and separation of W and Mo from aqueous solutions with simultaneous hydrogen production in stacked bioelectrochemical systems (BESs): Impact of heavy metals W(VI)/Mo(VI) molar ratio, initial pH and electrode material.

    Science.gov (United States)

    Huang, Liping; Li, Ming; Pan, Yuzhen; Quan, Xie; Yang, Jinhui; Puma, Gianluca Li

    2018-04-16

    The deposition and separation of W and Mo from aqueous solutions with simultaneous hydrogen production was investigated in stacked bioelectrochemical systems (BESs) composed of microbial electrolysis cell (1#) serially connected with parallel connected microbial fuel cell (2#). The impact of W/Mo molar ratio (in the range 0.01 mM : 1 mM and vice-versa), initial pH (1.5 to 4.0) and cathode material (stainless steel mesh (SSM), carbon rod (CR) and titanium sheet (TS)) on the BES performance was systematically investigated. The concentration of Mo(VI) was more influential than W(VI) in determining the rate of deposition of both metals and the rate of hydrogen production. Complete metal recovery was achieved at equimolar W/Mo ratio of 0.05 mM : 0.05 mM. The rates of metal deposition and hydrogen production increased at acidic pH, with the fastest rates at pH 1.5. The morphology of the metal deposits and the valence of the Mo were correlated with W/Mo ratio and pH. CR cathodes (2#) coupled with SSM cathodes (1#) achieved a significant rate of hydrogen production (0.82 ± 0.04 m 3 /m 3 /d) with W and Mo deposition (0.049 ± 0.003 mmol/L/h and 0.140 ± 0.004 mmol/L/h (1#); 0.025 ± 0.001 mmol/L/h and 0.090 ± 0.006 mmol/L/h (2#)). Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Colorimetric study of malvidin-3-O-glucoside copigmented by phenolic compounds: The effect of molar ratio, temperature, pH, and ethanol content on color expression of red wine model solutions.

    Science.gov (United States)

    Zhang, Bo; Yang, Xue-Shan; Li, Ning-Ning; Zhu, Xia; Sheng, Wen-Jun; He, Fei; Duan, Chang-Qing; Han, Shun-Yu

    2017-12-01

    In the recent research, the copigmentations of malvidin-3-O-glucoside with eight types of phenolic copigments have been investigated. The influence of the pigment/copigment molar ratio, the reaction temperature, the pH and the ethanol content of solutions has been examined. The results showed that the copigmentation effect was dependent on not only the particular structures of the phenolic compounds but also the factors of the reaction systems. The increase of the copigment concentration can strengthen the copigmentation effect, improve the solution color, and enhance the red-purple features. Different temperatures had different influences on the copigmentation reactions. The destruction of the copigmentation complexes can result in the hypsochromic shift of the reaction solution when the temperature was higher than 20°C. The bathochromic shift of the solution gradually progressed with the increase of the pH value. A significant copigmentation feature was spotted when pH reached 3.0, which demonstrates obvious red-purple characterization. The addition of the ethanol weakened the copigmentation effect. According to measurement through color analysis, it was found that the color differences caused by ethanol in red wine were typically attributed to quantitative changes. Remarkably, all of the above delicate color deviations caused by the structural or environmental factors can be precisely and conveniently depicted via the CIELAB space analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Characterization by Sem, EDS and micro-Raman of the influence of the molar ratio SiO2/Al2O3 and reduction temperature on the system CuZSM5

    International Nuclear Information System (INIS)

    Chavez R, F.; Rodriguez I, I.; Petranovskii, V.

    2014-01-01

    The morphological and spectroscopic changes caused by reduction of ion-exchanged CuZSM5 samples with SiO 2 /Al 2 O 3 molar ratios (MR) of 30 and 70 in H 2 flow at 150 and 350 grades C are discussed. the nominal copper loading was of 1% by weight. Scanning electron microscopy of CuZSM5 sample set showed that the treatment in reducing atmosphere at 350 grades C produces particle agglomeration and smoother surface texture that treatment at 150 grades C, this effect was more pronounced for the sample with MR 30. Furthermore, the particles corresponding to the sample with MR 30 are of irregular shape and have rough texture (cubic or rectangular crystals, protrusions) while the particles of the sample with MR 70 are in the majority of spherical smooth texture (leaf-shaped crystals/platelet, reclining). Energy Dispersive X-ray spectroscopy elemental analysis reveals a heterogeneous distribution of copper as well other elements in each sample. The micro-Raman spectroscopy shows some changes in the vibrational modes for the studied samples. (Author)

  3. Association between Peritonsillar Abscess and Molar Caries

    Directory of Open Access Journals (Sweden)

    M Shayani Nasab

    2006-05-01

    Full Text Available Background: Peritonsillar abscess is the most common deep neck infections that are related with periodontal disease which has the same pathogenesis. We determined the relationship between peritonsillar infection and molar caries. Methods: In a cross-sectional study, 33 consecutive patients whom referred to Hamadan university clinic of otolaryngologic for peritonsillar abscess were examined by otolaryngologist and dentist who investigated relationship between peritonsillar infection and molar caries. Results: There were 27 males and 6 females with mean age 26.7+_7 years. The frequency caries on ipsilateral peritonsillar infection sides was in relation to molars caries on opposite sides (conterol group. This corrolation was significant with odds ratio 2.5. Conclusion: Molar caries were seen 2.5 times more likely to have peritonsillar infection compared with normal molar sides. Key Words: Peritonsillar abscess, Infection, Periodontal disease, Dental caries

  4. Third molar development: measurements versus scores as age predictor.

    Science.gov (United States)

    Thevissen, P W; Fieuws, S; Willems, G

    2011-10-01

    Human third molar development is widely used to predict chronological age of sub adult individuals with unknown or doubted age. For these predictions, classically, the radiologically observed third molar growth and maturation is registered using a staging and related scoring technique. Measures of lengths and widths of the developing wisdom tooth and its adjacent second molar can be considered as an alternative registration. The aim of this study was to verify relations between mandibular third molar developmental stages or measurements of mandibular second molar and third molars and age. Age related performance of stages and measurements were compared to assess if measurements added information to age predictions from third molar formation stage. The sample was 340 orthopantomograms (170 females, 170 males) of individuals homogenously distributed in age between 7 and 24 years. Mandibular lower right, third and second molars, were staged following Gleiser and Hunt, length and width measurements were registered, and various ratios of these measurements were calculated. Univariable regression models with age as response and third molar stage, measurements and ratios of second and third molars as predictors, were considered. Multivariable regression models assessed if measurements or ratios added information to age prediction from third molar stage. Coefficients of determination (R(2)) and root mean squared errors (RMSE) obtained from all regression models were compared. The univariable regression model using stages as predictor yielded most accurate age predictions (males: R(2) 0.85, RMSE between 0.85 and 1.22 year; females: R(2) 0.77, RMSE between 1.19 and 2.11 year) compared to all models including measurements and ratios. The multivariable regression models indicated that measurements and ratios added no clinical relevant information to the age prediction from third molar stage. Ratios and measurements of second and third molars are less accurate age predictors

  5. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization

    Science.gov (United States)

    Negre-Barber, A.; Montiel-Company, J. M.; Boronat-Catalá, M.; Catalá-Pizarro, M.; Almerich-Silla, J. M.

    2016-01-01

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9–86.6) and the negative predictive value 84.7% (80.6–88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9–17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47–0.68). The odds ratio was 18.2 (9.39–35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH. PMID:27558479

  6. Removable molar power arm

    Directory of Open Access Journals (Sweden)

    Raj Kumar Verma

    2013-01-01

    Full Text Available Attachment of force elements from the gingival hook of maxillary molar tubes during the retraction of the anterior teeth is very common in orthodontic practice. As the line of force passes below the center of resistance (CR of molar, it results its mesial tipping and also anchorage loss. To overcome this problem, the line of force should pass along the CR of molar. This article highlights a method to overcome this problem by attaching a removable power arm to the headgear tube of molar tube during the retraction of the anterior teeth.

  7. Effect of Zn/Sn molar ratio on the microstructural and optical properties of Cu2Zn1-xSnxS4 thin films prepared by spray pyrolysis technique

    Science.gov (United States)

    Thiruvenkadam, S.; Prabhakaran, S.; Sujay Chakravarty; Ganesan, V.; Vasant Sathe; Santhosh Kumar, M. C.; Leo Rajesh, A.

    2018-03-01

    Quaternary kesterite Cu2ZnSnS4 (CZTS) compound is one of the most promising semiconductor materials consisting of abundant and eco-friendly elements for absorption layer in thin film solar cells. The effect of Zn/Sn ratio on Cu2Zn1-xSnxS4 (0 ≤ x ≤ 1) thin films were studied by deposited by varying molar volumes in the precursor solution of zinc and tin was carried out in proportion of (1-x) and x respectively onto soda lime glass substrates kept at 573 K by using chemical spray pyrolysis technique. The GIXRD pattern revealed that the films having composites of Cu2ZnSnS4, Cu2SnS3, Sn2S3, CuS and ZnS phases. The crystallinity and grain size were found to increase by increasing the x value and the preferential orientation along (103), (112), (108) and (111) direction corresponding to CZTS, Cu2SnS3, CuS, and ZnS phases respectively. Micro-Raman spectra exposed a prominent peak at 332 cm-1 corresponding to the CZTS phase. Atomic force microscopy was employed to study the grain size and roughness of the deposited thin films. The optical band gap was found to lie between 1.45 and 2.25 eV and average optical absorption coefficient was found to be greater than 105 cm-1. Hall measurements exhibited that all the deposited Cu2Zn1-xSnxS4 films were p type and the resistivity lies between 10.9 ×10-2Ωcm and 149.6 × 10-2Ωcm .

  8. Results, meta-analysis and a first evaluation of UNOxR, the urinary nitrate-to-nitrite molar ratio, as a measure of nitrite reabsorption in experimental and clinical settings.

    Science.gov (United States)

    Tsikas, Dimitrios; Hanff, Erik; Bollenbach, Alexander; Kruger, Ruan; Pham, Vu Vi; Chobanyan-Jürgens, Kristine; Wedekind, Dirk; Arndt, Tanja; Jörns, Anne; Berbée, Jimmy F P; Princen, Hans M G; Lücke, Thomas; Mariotti, François; Huneau, Jean-François; Ückert, Stefan; Frölich, Jürgen C; Lenzen, Sigurd

    2018-05-04

    We recently found that renal carbonic anhydrase (CA) is involved in the reabsorption of inorganic nitrite (NO 2 - ), an abundant reservoir of nitric oxide (NO) in tissues and cells. Impaired NO synthesis in the endothelium and decreased NO bioavailability in the circulation are considered major contributors to the development and progression of renal and cardiovascular diseases in different conditions including diabetes. Isolated human and bovine erythrocytic CAII and CAIV can convert nitrite to nitrous acid (HONO) and its anhydride N 2 O 3 which, in the presence of thiols (RSH), are further converted to S-nitrosothiols (RSNO) and NO. Thus, CA may be responsible both for the homeostasis of nitrite and for its bioactivation to RSNO/NO. We hypothesized that enhanced excretion of nitrite in the urine may contribute to NO-related dysfunctions in the renal and cardiovascular systems, and proposed the urinary nitrate-to-nitrite molar ratio, i.e., U NOx R, as a measure of renal CA-dependent excretion of nitrite. Based on results from clinical and experimental animal studies, here, we report on a first evaluation of U NOx R. We determined U NOx R values in preterm neonates, healthy children, and adults, in children suffering from type 1 diabetes mellitus (T1DM) or Duchenne muscular dystrophy (DMD), in elderly subjects suffering from chronic rheumatic diseases, type 2 diabetes mellitus (T2DM), coronary artery disease (CAD), or peripheral arterial occlusive disease (PAOD). We also determined U NOx R values in healthy young men who ingested isosorbide dinitrate (ISDN), pentaerythrityl tetranitrate (PETN), or inorganic nitrate. In addition, we tested the utility of U NOx R in two animal models, i.e., the LEW.1AR1-iddm rat, an animal model of human T1DM, and the APOE*3-Leiden.CETP mice, a model of human dyslipidemia. Mean U NOx R values were lower in adult patients with rheumatic diseases (187) and in T2DM patients of the DALI study (74) as compared to healthy elderly adults

  9. Influence of the Ti concentration and of the Ti:Mo molar ratio, in the efficiency of the {sup 99} Mo - {sup 99m} Tc generator, at basis of gels of titanium molybdates; Influencia de la concentracion de Ti y de la relacion molar Ti:Mo, en la eficiencia del generador {sup 99} Mo - {sup 99m} Tc a base de geles de molibdatos de titanio

    Energy Technology Data Exchange (ETDEWEB)

    Cortes R, O.; Monroy G, F.; Martinez C, T. [Facultad de Quimica, UNAM, 04510 Mexico D.F. (Mexico)]. e-mail: ocielcr@hotmail.com

    2003-07-01

    The {sup 99m} Tc, continues being the radionuclide more used in nuclear medicine to world scale. The production of this radioisotope, is carried out by means of generators {sup 99} Mo/{sup 99m} Tc that get ready commercially with {sup 99} Mo of high specific activity, adsorbed in alumina (2 mg {sup 99} Mo/g alumina) and that they are elutriated every 23 hours. In an alternative way, it is intended to use gels of titanium molybdates, as matrices of this generators. The gels are synthesized starting from solutions of ammonium molybdates and of titanium tetrachloride in aqueous media. These gels allow to incorporate until 25% of molybdenum in their structure, being been able to use {sup 99} Mo of low specific activity that can be obtained starting from the reaction {sup 98} Mo (n, {gamma}) {sup 99} Mo. With the object of producing generators of medium activity, with the base of gels of titanium molybdates, intends in this work, to study the influence of two synthesis parameters of these gels: the concentration of the titanium solutions and the molar ratio Ti: Mo. The decrease of the concentration of the titanium solution, used during the synthesis of the gels, is converted in an efficiency decrease and radionuclide purity of the generators, as well as an increment so much of the volume of elutriation, as of the pH of the elutriates. The gels that contain an major number of titanium moles, regarding the molybdenum moles, present a greater radionuclide purity, but they diminish their efficiency. The best characteristics for the gels synthesis of titanium molybdates are: a molar ratio 1:1 for Ti and Mo, and to use solutions of titanium whose concentration is near at 1 M. (Author)

  10. Ruptured tubal molar pregnancy

    African Journals Online (AJOL)

    2011-05-19

    May 19, 2011 ... In most instances, moles develop within the uterine cavity, but may occur at ... Patients with tubal molar pregnancy are very difficult to distinguish .... There was a left-sided adnexal mass, whose size could not be appreciated ...

  11. Molar Incisor Hypomineralisation

    NARCIS (Netherlands)

    Elfrink, M.; Weerheijm, K.L.

    2013-01-01

    Molar Incisor Hypomineralisation (mih) wordt omschreven als een hypomineralisatie (van systemische oorsprong) van één tot vier blijvende eerste molaren, vaak in combinatie met aangedane incisieven. mih-molaren zijn fragieler en cariësgevoeliger dan gewone molaren. Een kenmerk van mih-molaren is een

  12. Molar Incisor Hypomineralisation

    NARCIS (Netherlands)

    Elfrink, M.; Weerheijm, K.L.

    2009-01-01

    Molar Incisor Hypomineralisation (MIH) wordt gedefinieerd als een hypomineralisatie van systemische oorsprong van één tot vier blijvende eerste molaren, vaak in combinatie met aangedane incisieven. MIH-molaren zijn fragieler en cariësgevoeliger dan gewone molaren. Een kenmerk van MIH-molaren is een

  13. Molar Incisor Hypomineralisation

    NARCIS (Netherlands)

    Elfrink, M.; Weerheijm, K.

    2011-01-01

    Molar Incisor Hypomineralisation (mih ) wordt gedefinieerd als een hypomineralisatie van systemische oorsprong van één tot vier blijvende eerste molaren, vaak in combinatie met aangedane incisieven. mih -molaren zijn fragieler en cariësgevoeliger dan gewone molaren. Een kenmerk van mih -molaren is

  14. Relationship between mandibular condyle and angle fractures and the presence of mandibular third molars.

    Science.gov (United States)

    Mah, Deuk-Hyun; Kim, Su-Gwan; Moon, Seong-Yong; Oh, Ji-Su; You, Jae-Seek

    2015-02-01

    We retrospectively evaluated the impact of mandibular third molars on the occurrence of angle and condyle fractures. This was a retrospective investigation using patient records and radiographs. The sample set consisted of 440 patients with mandibular fractures. Eruption space, depth and angulation of the third molar were measured. Of the 144 angle fracture patients, 130 patients had third molars and 14 patients did not. The ratio of angle fractures when a third molar was present (1.26 : 1) was greater than when no third molar was present (0.19 : 1; odds ratio, 6.58; Pcondyle fractures patients, the third molar was present in 84 patients and absent in 57 patients. The ratio of condyle fractures when a third molar was present (0.56 : 1) was lower than when no third molar was present (1.90 : 1; odds ratio, 0.30; Pfractures with third molars and the ratio of condyle fractures without a third molar were statistically significant. The occurrence of angle and condyle fractures was more affected by the continuity of the cortical bone at the angle than by the depth of a third molar. These results demonstrate that a third molar can be a determining factor in angle and condyle fractures.

  15. Characterization by Sem, EDS and micro-Raman of the influence of the molar ratio SiO{sub 2}/Al{sub 2}O{sub 3} and reduction temperature on the system CuZSM5; Caracterizacion por SEM, EDS y micro-Raman de la influencia de la relacion molar SiO{sub 2}/Al{sub 2}O{sub 3} y temperatura de reduccion sobre el sistema CuZSM5

    Energy Technology Data Exchange (ETDEWEB)

    Chavez R, F. [Instituto Politecnico Nacional, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, 07738 Mexico D. F. (Mexico); Rodriguez I, I. [Universidad de la Habana, Instituto de Ciencia y Tecnologia de Materiales, Zapata y G. s/n, 10400 La Habana (Cuba); Petranovskii, V., E-mail: fchavez@esfm.ipn.mx [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 14, 22800 Ensenada, Baja California (Mexico)

    2014-07-01

    The morphological and spectroscopic changes caused by reduction of ion-exchanged CuZSM5 samples with SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios (MR) of 30 and 70 in H{sub 2} flow at 150 and 350 grades C are discussed. the nominal copper loading was of 1% by weight. Scanning electron microscopy of CuZSM5 sample set showed that the treatment in reducing atmosphere at 350 grades C produces particle agglomeration and smoother surface texture that treatment at 150 grades C, this effect was more pronounced for the sample with MR 30. Furthermore, the particles corresponding to the sample with MR 30 are of irregular shape and have rough texture (cubic or rectangular crystals, protrusions) while the particles of the sample with MR 70 are in the majority of spherical smooth texture (leaf-shaped crystals/platelet, reclining). Energy Dispersive X-ray spectroscopy elemental analysis reveals a heterogeneous distribution of copper as well other elements in each sample. The micro-Raman spectroscopy shows some changes in the vibrational modes for the studied samples. (Author)

  16. Treating Intraradicular Pockets of molars

    Directory of Open Access Journals (Sweden)

    H. Lotfizade

    1987-10-01

    Full Text Available It appears that until bone graft has not achieved 100% success, intraradicular diseases remain controversial and therefore, different treatment plans are suggested for them. Treating intraradicular diseases depend on many factors: maxillary molars are more prone to bone loss and have worse prognosis. To assess prognosis more carefully these factors should be considered: 1 bone loss: its apical depth, local or generalized 2 bone condition: buccal, lingual, mesial and distal aspects 3 tooth mobility: grades 2 and 3 have not good prognosis. Crown root ratio is also important. 4 the angle of divergence of roots: the more the roots are divergent, the better the prognosis would be. 5adjacent teeth health 6tooth position in jaws 7 age and general health of the patients 8 oral hygiene In general, teeth with 2 roots can be treated more effectively than 3 root ones. Maxillary first premolars are exceptions that do not respond to the treatments positively. We should look forward to the future investigations and findings.

  17. Molar Incisiv Hypomineralisasjon - MIH Litteraturstudie

    OpenAIRE

    Khan, Aisha Farnaz

    2017-01-01

    Introduksjon: MIH er definert som emaljehypomineralisering av systemisk opprinnelse der 1 til 4 av første permanente molarer er rammet. Incisiver er også ofte affiserte. Hensikten med denne litteraturstudien er å lage en oversikt over, og vurdere tilgjengelig litteratur om MIH, og bruke litteraturen som bakgrunn for å utarbeide en informasjonsbrosjyre om MIH. Materiale og metode: Det ble utført et elektronisk søk i PubMed med søkestrengene ”Molar incisor hypomineralization MIH” og ”Molar inci...

  18. Size of the lower third molar space in relation to age in Serbian population.

    Science.gov (United States)

    Zelić, Ksenija; Nedeljković, Nenad

    2013-10-01

    It is considered that the shortage of space is the major cause of the third molar impaction. The aim of this study was to establish the frequency of insufficient lower third molar eruption space in Serbian population, to question the differences in this frequency in the subjects of different age, to determine the influence of the lower third molar space (retromolar space) size on third molar eruption, and to investigate a possible correlation between the size of gonial angle and the space/third molar width ratio. Digital orthopantomograms were taken from 93 patients divided into two groups: early adult (16-18 years of age) and adult (18-26) patients. Retromolar space, mesiodistal third molar crown width, gonial angle and eruption levels were measured. The space/third molar width in early adult subjects was smaller (p third molars erupted in case of enough space in both age groups (p third molar width ratio is more favorable in adult subjects. Gonial angle is not in correlation with the retromolar space/third molar width ratio.

  19. Endodontic treatment of a mandibular second molar with four roots – A case report and literature review

    Directory of Open Access Journals (Sweden)

    Jorge N.R. Martins

    2014-06-01

    Conclusions: A configuration with four roots is rare for the mandibular molars. This configuration has an incidence of 0.04% in the first lower molar with only three in vivo case reports available. For the second lower molar, no incidence ratio was found.

  20. Fusion of mandibular third molar with supernumerary fourth molar

    OpenAIRE

    López Carriches, C.; Leco Berrocal, I.; Baca Pérez-Bryan, R.

    2008-01-01

    La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia...

  1. Nutrient Composition and Phytate-Zinc Molar Ratio of Prepared ...

    African Journals Online (AJOL)

    Objective: The aim of this study is to provide information on the variety and nutrient content of prepared dishes offered preschool children living in rural villages. Materials and Methods: Respondents for this study were 116 preschool children living in University Agriculture Abeokuta [UNAAB] extension villages in Ogun State ...

  2. Endodontic management of a mandibular third molar fused with a fourth molar.

    Science.gov (United States)

    Turell, I L; Zmener, O

    1999-05-01

    Developmental anomalies in permanent molars frequently require surgical intervention. A case of a mandibular third molar fused with a fourth molar which was successfully treated with conservative endodontic therapy is reported.

  3. Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients.

    Science.gov (United States)

    Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong

    2013-12-01

    This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

  4. Molar development in sheep: morphology, radiography, microhardness

    International Nuclear Information System (INIS)

    Milhaud, G.; Nezit, J.

    1991-01-01

    The chronology of molar development is studied from radiographic and macroscopic observations on 48 south Pre-Alps were living under optimal nutritional conditions. It was found that the first molar started its development in utero, the second molar at one month after birth, and the third molar, at 9-10 months. The first molar emerged into the oral cavity at 3 months, the second at 9 months and the third molar at 18 months. The first molar began the development of its roots at 6-7 months, the second molar at 11-12 months and the third molar at 20-22 months. The first molar reached completion of the growth of its roots at 3.5-4 years, the second and the third molars at about 6 years. The molars show the particularity of being functional during the three months which follow their eruption although the development of the crown is not completed. Then the accelerated wear is only partially compensated by the growth of the roots. The study also shows how the combined effects of wear and dentine deposit in the pulp cavity affect the morphology of molars. It reveals the marked hardness of enamel (240 Vickers units) and the low resistance of dentine at the surface of attrition (30 Vickers units)

  5. Fracture behavior of human molars.

    Science.gov (United States)

    Keown, Amanda J; Lee, James J-W; Bush, Mark B

    2012-12-01

    Despite the durability of human teeth, which are able to withstand repeated loading while maintaining form and function, they are still susceptible to fracture. We focus here on longitudinal fracture in molar teeth-channel-like cracks that run along the enamel sidewall of the tooth between the gum line (cemento-enamel junction-CEJ) and the occlusal surface. Such fractures can often be painful and necessitate costly restorative work. The following study describes fracture experiments made on molar teeth of humans in which the molars are placed under axial compressive load using a hard indenting plate in order to induce longitudinal cracks in the enamel. Observed damage modes include fractures originating in the occlusal region ('radial-median cracks') and fractures emanating from the margin of the enamel in the region of the CEJ ('margin cracks'), as well as 'spalling' of enamel (the linking of longitudinal cracks). The loading conditions that govern fracture behavior in enamel are reported and observations made of the evolution of fracture as the load is increased. Relatively low loads were required to induce observable crack initiation-approximately 100 N for radial-median cracks and 200 N for margin cracks-both of which are less than the reported maximum biting force on a single molar tooth of several hundred Newtons. Unstable crack growth was observed to take place soon after and occurred at loads lower than those calculated by the current fracture models. Multiple cracks were observed on a single cusp, their interactions influencing crack growth behavior. The majority of the teeth tested in this study were noted to exhibit margin cracks prior to compression testing, which were apparently formed during the functional lifetime of the tooth. Such teeth were still able to withstand additional loading prior to catastrophic fracture, highlighting the remarkable damage containment capabilities of the natural tooth structure.

  6. CANINE ECTOPIC TREATMENT WITH FIRST MOLAR EXTRACTION

    Directory of Open Access Journals (Sweden)

    Angelica Margo

    2015-06-01

    Full Text Available Decision to extract or not and the type of tooth must be analyzed carefully in orthodontic treatment. Preferable tooth to be extracted was the tooth with large caries or restoration. Usually the type of tooth to be extracted was second molar (if the third molar appears, incisor, first molar, and combination of several teeth. Orthodontic treatment with molar extraction is more difficult to treat and the result is usually compromise. There are several considerations in extracting first molar such as tooth with large caries or restoration, hypoplasia, periapical disease, large discrepancy, high maxilla-mandibular plane angle, and cases with anterior open bite. Nowadays, orthodontic cases with molar extraction do not prolong the treatment time compared to premolar extraction case, but the anchorage system must be considered carefully. The present case was treated with extraction of first molar to solve anterior crowding with maximum anchorage at the upper jaw and using Nance Holding Appliance.

  7. Adhesives for bonded molar tubes during fixed brace treatment.

    Science.gov (United States)

    Millett, Declan T; Mandall, Nicky A; Mattick, Rye Cr; Hickman, Joy; Glenny, Anne-Marie

    2017-02-23

    date of publication when searching the electronic databases. Randomised controlled trials of participants with full arch fixed orthodontic appliance(s) with molar tubes, bonded to first or second permanent molars. Trials which compared any type of adhesive used to bond molar tubes (stainless steel or titanium) with any other adhesive, were included.Trials were also included where:(1) a tube was bonded to a molar tooth on one side of an arch and a band cemented to the same tooth type on the opposite side of the same arch;(2) molar tubes had been allocated to one tooth type in one patient group and molar bands to the same tooth type in another patient group. The selection of papers, decision about eligibility and data extraction were carried out independently and in duplicate without blinding to the authors, adhesives used or results obtained. All disagreements were resolved by discussion. Two trials (n = 190), at low risk of bias, were included in the review and both presented data on first time failure at the tooth level. Pooling of the data showed a statistically significant difference in favour of molar bands, with a hazard ratio of 2.92 (95% confidence intervals (CI) 1.80 to 4.72). No statistically significant heterogeneity was shown between the two studies. Data on first time failure at the patient level were also available and showed statistically different difference in favour of molar bands (risk ratio 2.30; 95% CI 1.56 to 3.41) (risk of event for molar tubes = 57%; risk of event for molar bands 25%).One trial presented data on decalcification again showing a statistically significant difference in favour of molar bands. No other adverse events identified. From the two well-designed and low risk of bias trials included in this review it was shown that the failure of molar tubes bonded with either a chemically-cured or light-cured adhesive was considerably higher than that of molar bands cemented with glass ionomer cement. One trial indicated that there was less

  8. Expressly fabricated molar tube bases: enhanced adhesion.

    Science.gov (United States)

    Sharma, Tarun; Phull, Tarun Singh; Rana, Tarun; Kumar, Varun

    2014-06-01

    Clinicians, Orthodontists and their patients' parents often expect the best results in the shortest time span possible. Orthodontic bonding of molar tubes has been an acceptable risk in a modern era of refined biomaterials and instrumentation. Although many orthodontists still prefer banding to bonding, it is the failure rate of the tubes on molars which accounts to an impedance in molar bonding. One of the reasons for molar attachment failures is attributed to improper adaptation of the buccal tube base with or without increased thickness of composite. Merits of banding the second molars especially when these are the terminal teeth for anchorage have been overemphasized in the literature. The present article presents a simple and relatively less time consuming technique of preparing molar tubes to be bonded on tooth surfaces which may be quite difficult to isolate especially for bonding, for example, mandibular second molars. The increased surface area of the composite scaffold helps not only in enhanced bond strength but also serves to reduce the incidence of plaque accumulation given the dexterity of invitro preparation. The removal of the occlusal part of the molar tube scaffold helps in prevention of open / raised bite tendencies. The present innovation, therefore, is not merely serendipity but a structured technique to overcome a common dilemma for the clinical orthodontist. The present dictum of banding being superior to molar tube bonding may prove to be futile with trendsetting molar attachments. It is also an established fact that bonding proves to be a lesser expensive modality when compared to banding procedures.

  9. External and internal anatomy of third molars.

    Science.gov (United States)

    Guerisoli, D M; de Souza, R A; de Sousa Neto, M D; Silva, R G; Pécora, J D

    1998-01-01

    The external and internal anatomy of 269 third molars (155 maxillary and 114 mandibular) were studied. The teeth were measured, classified according to their root number and shape and the internal anatomy was observed by the use of diaphanization. A great anatomical variability was found, with the presence of up to 5 roots in maxillary third molars and 3 roots in mandibular third molars. The number of root canals followed the same pattern.

  10. Pulpectomy procedures in primary molar teeth

    OpenAIRE

    Hany Mohamed Aly Ahmed

    2014-01-01

    Premature loss of primary molars can cause a number of undesirable consequences including loss of arch length, insufficient space for erupting premolars and mesial tipping of the permanent molars. Pulpectomy of primary molar teeth is considered as a reasonable treatment approach to ensure either normal shedding or a long-term survival in instances of retention. Despite being a more conservative treatment option than extraction, efficient pulpectomy of bizarre and tortuous root canals encased ...

  11. Permanent molars: Delayed development and eruption

    Directory of Open Access Journals (Sweden)

    Arathi R

    2006-05-01

    Full Text Available Delayed development and eruption of all the permanent molars is a rare phenomenon, which can cause disturbance in the developing occlusion. The eruption of permanent first and second molars is very important for the coordination of facial growth and for providing sufficient occlusal support for undisturbed mastication. In the case described, the first permanent molars were delayed in their development and were seen erupting at the age of nine and a half years. Severe disparity between the left and the right side of the dentition with respect to the rate of development of molars were also present.

  12. Dental lesions and restorative treatment in molars

    Directory of Open Access Journals (Sweden)

    Gheorghiu Irina-Maria

    2017-08-01

    Full Text Available This article review specific clinical issues of the molar teeth, as well as the therapeutic approach of their pathology. The dental pathology we face in the group of molars is related to: dental caries, dental trauma (crown and crown-root fractures, dental wear phenomena. The therapeutic approach of the molar teeth is represented by: restoration of the loss of hard dental tissues; endodontic treatments of pulpal and periapical complications; surgical treatment. The restorative treatments in molars are: direct restorations, with or without supplementary anchorage for obturations; inlay, onlay; prosthetic crown.

  13. Incidence of root canal treatment of second molars following adjacent impacted third molar extraction

    Directory of Open Access Journals (Sweden)

    Yener Oguz

    2016-03-01

    Conclusion: Although the incidence is minimal, iatrogenic subluxation injuries occurring during the surgical removal of impacted third molars can lead to pulpal complications and a requirement for root canal treatment of adjacent second molars.

  14. Partial molar volumes of hydrogen and deuterium in niobium, vanadium, and tantalum

    International Nuclear Information System (INIS)

    Peterson, D.T.; Herro, H.M.

    1983-01-01

    The partial molar volumes of hydrogen and deuterium were measured in vanadium, niobium, and tantalum by a differential pressure technique. One-half of an electrolytically charged sample plat was compressed between hardened steel blocks in a hydraulic press. The activity of hydrogen in the hig pressure region was raised and caused hydrogen to diffuse into the low pressure region. The partia molar volume was calculated from the ratio of the hydrogen concentrations in the high and low pressure regions of the sample. Small isotope effects were found in the partial molar volume. Hydrogen had the larger volume in niobium and tantalum, but the reverse was true in vanadium

  15. Mini implant supported molar tubes: A novel method for attaching the molar tubes

    Directory of Open Access Journals (Sweden)

    Nitin V Muralidhar

    2017-01-01

    Full Text Available Banding or bonding procedures have been the only means of attaching molar tubes onto the permanent molar teeth till date in the field of orthodontics. This clinical innovation aims to include the use of mini implant for the purpose of attaching the molar tubes thereby eliminating the iatrogenic effects of banding and bonding of the teeth.

  16. Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

    International Nuclear Information System (INIS)

    Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong

    2013-01-01

    This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

  17. Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

    Energy Technology Data Exchange (ETDEWEB)

    Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong [Chiang Mai University, Chiang Mai (Thailand)

    2013-12-15

    This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

  18. Morphologic study of the maxillary molars. Part II: Internal anatomy.

    Science.gov (United States)

    Pécora, J D; Woelfel, J B; Sousa Neto, M D; Issa, E P

    1992-01-01

    The internal anatomy of three hundred and seventy (370) decalcified and cleared human maxillary molars was studied. Seventy-five percent of the first molars, 58% of the second molars and 68% of the third molars studied presented three (3) root canals and 25% of the first molars, 42% of the second molars and 32% of the third molars presented four (4) root canals. The authors observed that the incidence of two root canals in the mesiobuccal root was higher in second maxillary molars than in first maxillary molars.

  19. [Correlation between the lower first permanent molar axis and the premature loss of temporary molars].

    Science.gov (United States)

    Petcu, Ana; Maxim, A; Haba, Danisia

    2009-01-01

    The aim of our study was to determine the impact of premature loss of temporary molars upon the longitudinal axis of the first permanent molar. The study sample was formed by 94 orthopanthomografies of child patients with premature loss of lower temporary molars (first or second) after clinical eruption of the first permanent molar. All panoramic radiographs have been realized with the same panoramic unit with 1.4% magnification coefficient and were analyzed using a standardized technique of tracing the images of teeth and bone on matte acetate paper. It was evaluated the angle between longitudinal axis of first permanent lower molar and occlusal plane. It was observed that premature loss of lower second deciduous molar modifies greater the vertical axis of first permanent molar (between 61 degrees and 79 degrees) then premature loss of first lower primary molar. This is perhaps because the loss of space in the case of premature exfoliation of first primary molar is due more to distal drift of canine then mesial drift of molars. The drift to mesial of first permanent molar is more accentuated proportional with the age at which appeared premature loss and so it is loss of leeway space.

  20. The influence of premature loss of temporary upper molars on permanent molars.

    Science.gov (United States)

    Cernei, E R; Maxim, Dana Cristiana; Zetu, Irina Nicoleta

    2015-01-01

    Premature loss of primary molars due to dental caries and their complications has been associated with space loss and eruptive difficulties, especially when the loss occurs early. The aim of our study was to determine the impact of premature loss of temporary upper molars upon the longitudinal axis of the first and second upper permanent molar. The study group included 64 patients 6-9 years old with premature loss of primary molars and a control group of 48 patients with intact temporary teeth. It was evaluated the angle between longitudinal axis of first and second upper permanent molars and occlusal plane. The sofware used is Easy Dent 4 Viewer®.The data were analyzed by using the Statistical Package for the Social Sciences (version 20.0; SPSS, Chicago, III). It was observed that premature loss of upper second deciduous molars modifies greater the vertical axis of the permanent molars than the premature loss of first upper primary molar. First upper primary molar loss cause an acceleration eruption of first premolar, which will produce a distal inclintion of the both permanent molars. The use of space maintainers after premature loss of the second upper temporary molar is a last solution in preventing tridimensional lesions in the dental arch and occlusion.

  1. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Science.gov (United States)

    Souki, Bernardo Q.; Cheib, Paula L.; de Brito, Gabriela M.; Pinto, Larissa S. M. C.

    2015-01-01

    Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction. PMID:26321848

  2. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Directory of Open Access Journals (Sweden)

    Bernardo Q Souki

    2015-01-01

    Full Text Available Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

  3. Analysis of the mineral composition of hypomineralized first permanent molars

    Directory of Open Access Journals (Sweden)

    Martinović Brankica

    2015-01-01

    Full Text Available Background/Aim. Hypomineralization of molars and incisors (molar-incisor hypomineralization - MIH is defined as enamel hypomineralization of systemic origin of one or more of the four first permanent molars, which may be associated with changes in the maxillary, and less frequently in the permanent mandibular incisors. The aim of this study was to investigate the mineral content in hypomineralized teeth as a contribution to under-standing the origin of these changes, which will be important for effective restorative approach. Methods. A total of 10 extracted first permanent molars diagnosed with MIH were used in the study as the experimental group, and intact first premolars extracted for orthodontic reasons were used as the control group. A certain surface of hypomineralized аnd healthy enamel and dentin was analyzed using a scanning electron microscope equipped with an energydispersive spectrometer (SEM/EDS. Results. By conducting quantitative chemical analysis of the distribution of the basic chemical elements, it was found that the concentration of calcium (Ca and phosphorus (P was significantly higher in healthy enamel (Ca = 28.80 wt%, and P = 15.05 wt% compared to hypomineralized enamel (Ca = 27.60 wt% and P = 14.32 wt%. Carbon (C concentration was statistically significantly higher in hypomineralized enamel (C = 11.70 wt% compared to healthy enamel (C = 10.94 wt%. Hypomineralized and healthy enamel did not differ significantly regarding the ratio of calcium and phosphorus concentrations whereas the ratio of calcium and carbon concentrations was statistically significantly higher in healthy enamel compared to hypomineralized enamel. Conclusion. Concentration of the main chemical elements, primarily calcium and phosphorus, is significantly reduced in hypomineralized enamel whereas carbon concentration is increased compared to healthy enamel.

  4. Rare occurrence of the left maxillary horizontal third molar impaction ...

    African Journals Online (AJOL)

    Rare occurrence of the left maxillary horizontal third molar impaction, the right maxillary third molar vertical impaction and the left mandibular third molar vertical impaction with inferior alveolar nerve proximity in a 30 year old female: a case report.

  5. Fusión de un tercer molar mandibular con un cuarto molar supernumerario Fusion of mandibular third molar with supernumerary fourth molar

    Directory of Open Access Journals (Sweden)

    C. López Carriches

    2008-10-01

    Full Text Available La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia del cordal semiincluido bajo anestesia local. Llevamos a cabo una revisión bibliográfica al respecto.Dental fusion is the union of two tooth buds that normally are separated, while gemination is defined as an attempt by a single tooth bud to divide. The fusion and gemination of molars is uncommon in permanent teeth. We report a clinical case of a right lower third molar fused to a supernumerary fourth molar in a 36-year-old male patient with repeated episodes of inflammation. After the radiologic study, the semi-impacted third molar was extracted under local anesthesia. The literature was reviewed.

  6. Autogenous transplantation of maxillary and mandibular molars.

    Science.gov (United States)

    Reich, Peter P

    2008-11-01

    Autogenous tooth transplantation has been used as a predictable surgical approach to correct malocclusion and replace edentulous areas. This article focuses on the surgical approach and technique for molar transplantation. Thirty-two patients aged between 11 and 25 years underwent 44 autogenous molar transplantations. The procedure involved transplantation of impacted or newly erupted third molars into the extraction sockets of nonrestorable molars and surgical removal and replacement of horizontally impacted molars into their proper vertical alignment. Five basic procedural concepts were applied: 1) atraumatic extraction, avoiding disruption of the root sheath and root buds; 2) apical contouring of bone at the transplantation site and maxillary sinus lift via the Summers osteotome technique, when indicated, for maxillary molars; 3) preparation of a 4-wall bony socket; 4) avoidance of premature occlusal interferences; and 5) stabilization of the tooth with placement of a basket suture. All 32 patients successfully underwent the planned procedure. To date, 2 patients have had localized infection that resulted in loss of the transplant. The remaining 42 transplants remain asymptomatic and functioning, with a mean follow-up period of 19 months. No infection, ankylosis, loss of the transplant, or root resorption has been noted. In addition, endodontic therapy has not been necessary on any transplanted teeth. Autogenous tooth transplantation has been discussed and described in the literature previously, with a primary focus on cuspid and bicuspid transplantation. The molar transplant is infrequently discussed in today's literature, possibly because of the preponderance of titanium dental implants. Autogenous molar transplantation is a viable procedure with low morbidity and excellent functional and esthetic outcomes. This report shows the successful transplantation of 42 of 44 molars in 32 patients with a mean follow-up period of 19 months.

  7. Treatment of ectopic first permanent molar teeth.

    LENUS (Irish Health Repository)

    Hennessy, Joe

    2012-11-01

    Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. CLINICAL RELEVANCE: This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

  8. Mini-implant-supported Molar Distalization

    Directory of Open Access Journals (Sweden)

    Amit Goyal

    2012-01-01

    Full Text Available Temporary anchorage devices popularly called mini-implants or miniscrews are the latest addition to an orthodontist′s armamentarium. The following case report describes the treatment of a 16-year-old girl with a pleasant profile, moderate crowding and Angle′s Class II molar relationship. Maxillary molar distalization was planned and mini-implants were used to preserve the anterior anchorage. After 13 months of treatment, Class I molar and canine relation was achieved bilaterally and there was no anterior proclination. Thus, mini-implants provide a viable option to the clinician to carry out difficult tooth movements without any side effects.

  9. Treatment of ectopic first permanent molar teeth.

    Science.gov (United States)

    Hennessy, Joe; Al-Awadhi, E A; Dwyer, Lian O; Leith, Rona

    2012-11-01

    Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

  10. The premature loss of primary first molars: space loss to molar occlusal relationships and facial patterns.

    Science.gov (United States)

    Alexander, Stanley A; Askari, Marjan; Lewis, Patricia

    2015-03-01

    To investigate space changes with the premature loss of primary first molars and their relationship to permanent molar occlusion and facial forms. Two hundred twenty-six participants (ranging in age from 7 years 8 months to 8 years 2 months; 135 female, 91 male) met all inclusion criteria designed to study space loss as a result of the premature loss of the primary first molar. After 9 months, space loss was evaluated in relationship to molar occlusion and facial form. Statistical evaluation was performed with the paired t-test and with a two-way analysis of variance for independent groups. Patients with leptoprosopic facial form and end-on molar occlusions all exhibited a statistically significant difference when compared to controls in terms of space loss (P molar occlusion displayed space loss as well (P molar occlusion displayed space loss in the maxilla (P molar occlusions showed no significant difference in space loss. The relationship between the first permanent molar occlusion and facial form of the child has an influence on the loss of space at the primary first molar site.

  11. AXIAL MODIFICATIONS OF PERMANENT LOWER MOLARS AFTER PREMATURE LOSSES OF TEMPORARY MOLARS.

    Science.gov (United States)

    Cernei, E R; Mavru, R B; Zetu, Irina Nicoleta

    2016-01-01

    The aim of our study was to determine the impact of premature loss of temporary lower molars upon the longitudinal axis of the first and second permanent molars. The study groups included 61 patients, 6-9 year olds with premature loss of primary molars and a control group of 24 patients with intact temporary teeth. We evaluated the angle between longitudinal axis of first and second lower permanent molars and occlusal plane. It was observed that premature loss of lower second deciduous molar modifies more the vertical axis of first and second permanent molars than the premature loss of first lower primary molar. Reducing space occurs mainly through mesial inclination of molars that separates the edentulous breach. Temporary loss of both lower first molars on the same quadrant causes an accelerated eruption of both premolars increasing the prevalence of eruption sequence: "4-5-3-7". The preservation of the occlusal morpho-functional complex using space maintainers mainly when the premature loss of the second primary molars occurs is the best interceptive treatment option.

  12. Radiographic assessment of lower third molar eruption in different anteroposterior skeletal patterns and age-related groups.

    Science.gov (United States)

    Jakovljevic, Aleksandar; Lazic, Emira; Soldatovic, Ivan; Nedeljkovic, Nenad; Andric, Miroslav

    2015-07-01

    To analyze radiographic predictors for lower third molar eruption among subjects with different anteroposterior skeletal relations and of different age groups. In total, 300 lower third molars were recorded on diagnostic digital orthopantomograms (DPTs) and lateral cephalograms (LCs). The radiographs were grouped according to sagittal intermaxillary angle (ANB), subject age, and level of lower third molar eruption. The DPT was used to analyze retromolar space, mesiodistal crown width, space/width ratio, third and second molar angulation (α, γ), third molar inclination (β), and gonion angle. The LC was used to determine ANB, angles of maxillar and mandibular prognathism (SNA, SNB), mandibular plane angle (SN/MP), and mandibular lengths. A logistic regression model was created using the statistically significant predictors. The logistic regression analysis revealed a statistically significant impact of β angle and distance between gonion and gnathion (Go-Gn) on the level of lower third molar eruption (P third molar impaction rate was significantly higher in the adult subgroup with the Class II (62.3%) compared with Class III subjects (31.7%; P third molar eruption were measured in Class III subjects. For valid estimation of mandibular third molar eruption, certain linear and angular measures (β angle, Go-Gn), as well as the size of the retromolar space, need to be considered.

  13. Endodontic therapy for a fused mandibular molar.

    Science.gov (United States)

    Rotstein, I; Moshonov, J; Cohenca, N

    1997-06-01

    Variations in tooth morphology present a clinical challenge when endodontic treatment is required. A case of conservative endodontic therapy for a fused mandibular second and third molar is presented.

  14. A Molar Pregnancy within the Fallopian Tube

    Directory of Open Access Journals (Sweden)

    Laura Allen

    2016-01-01

    Full Text Available Background. Discussion of the incidence of molar pregnancy and ectopic pregnancy. Role of salpingostomy and special considerations for postoperative care. Case. The patient is a 29-year-old G7P4 who presented with vaginal bleeding in the first trimester and was initially thought to have a spontaneous abortion. Ultrasound was performed due to ongoing symptoms and an adnexal mass was noted. She underwent uncomplicated salpingostomy and was later found to have a partial molar ectopic pregnancy. Conclusion. This case illustrates the rare occurrence of a molar ectopic pregnancy. There was no indication of molar pregnancy preoperatively and this case highlights the importance of submitting and reviewing pathological specimens.

  15. Management of large losses of substances molars

    OpenAIRE

    Reynal, Florence

    2016-01-01

    This work aims to compare the different coronary restorative materials used for large tooth losses in primary molars. The first part of this thesis is dedicated to a description of the four main materials used in coronary restorations of molars : amalgam, glass-ionomer cements, resin-based composite and pedodontic crown. The second part is a systematic review of the literature. The aim is to compare the long-term survival rates of different restoration techniques, in order to help the practit...

  16. Microstructure of a tribosphenic molar - comparative analysis

    OpenAIRE

    ŠPOUTIL, František

    2010-01-01

    The proposed thesis concerns in the study of tribosphenic molar, the key apomorphy of mammalian clade, mainly in structure and development of its enamel coat. As the main model species served us European vespertilionid bat Myotis myotis. The aims of this thesis are: (1) to describe structure and microstructure of enamel in tribosphenic molars in detail; (2) to compare it with unicuspid teeth of the same dentition; (3) to describe mineralization process and enamel maturation in insectivorous d...

  17. Maxillary molar distalization with first class appliance.

    Science.gov (United States)

    Ramesh, Namitha; Palukunnu, Biswas; Ravindran, Nidhi; Nair, Preeti P

    2014-02-27

    Non-extraction treatment has gained popularity for corrections of mild-to-moderate class II malocclusion over the past few decades. The distalization of maxillary molars is of significant value for treatment of cases with minimal arch discrepancy and mild class II molar relation associated with a normal mandibular arch and acceptable profile. This paper describes our experience with a 16-year-old female patient who reported with irregularly placed upper front teeth and unpleasant smile. The patient was diagnosed to have angles class II malocclusion with moderate maxillary anterior crowding, deep bite of 4 mm on a skeletal class II base with an orthognathic maxilla and retrognathic mandible and normal growth pattern. She presented an ideal profile and so molar distalization was planned with the first-class appliance. Molars were distalised by 8 mm on the right and left quadrants and class I molar relation achieved within 4 months. The space gained was utilised effectively to align the arch and establish a class I molar and canine relation.

  18. Predicting pathology in impacted mandibular third molars

    Directory of Open Access Journals (Sweden)

    Aveek Mukherji

    2017-01-01

    Full Text Available Introduction: The rising incidence of the impacted mandibular third molars and their association with pathologies is now considered a public health problem. Aims and Objectives: The objective of this study was to assess the position of impacted mandibular third molars that are prone to developing pathologies and to determine the frequency and type of pathological conditions associated with these impacted teeth to facilitate planning for their prophylactic removal. Materials and Methods: Consecutive panoramic radiographs and clinical examination of 300 patients with impacted mandibular third molars were collected. They were segregated according to Pell and Gregory’s classification, Winter’s classification, and according to their state of eruption. These were correlated with associated pathologies based on clinical and radiological criteria. Statistical Analysis Used: Descriptive statistics included computation of percentages, mean, and standard deviations. The statistical test applied for the analysis was Pearson’s Chi-square test (χ2. For this test, confidence interval and P value were set at 93% and ≤0.03, respectively. Results: The pathology most commonly associated with impacted third molars was pericoronitis, which had the highest frequency of occurrence in partially erupted, distoangular, and IA positioned (as per Pell and Gregory classification impacted teeth. Impacted mandibular third molars, which were in IA position, placed mesially, and partially erupted, were prone to develop pathologies such as dental caries and periodontitis. Conclusion: The clinical and radiographical features of impacted third molar may be correlated to the development of their pathological complications. The partially impacted mandibular third molars with mesioangularly aligned in IA position have the highest potential to cause pathological complications.

  19. Bilateral maxillary fused second and third molars: a rare occurrence.

    Science.gov (United States)

    Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

    2012-12-01

    This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months.

  20. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    Science.gov (United States)

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  1. Does fixed retention prevent overeruption of unopposed mandibular second molars in maxillary first molar extraction cases?

    NARCIS (Netherlands)

    Livas, Christos; Halazonetis, Demetrios J; Booij, Johan W; Katsaros, Christos; Ren, Yijin

    2016-01-01

    BACKGROUND: The objective of this study was to investigate whether multistranded fixed retainers prevented overeruption of unopposed mandibular second molars in maxillary first molar extraction cases. METHODS: The panoramic radiographs of 65 Class II Division 1 Caucasian Whites (28 females, 37

  2. SECOND MOLAR UPRIGHTING AFTER PREMATURE LOSS OF MANDIBULAR FIRST PERMANENT MOLAR--CASE REPORT.

    Science.gov (United States)

    Cernei, E R; Mavru, R B; Zetui, Irina Nicoleta

    2015-01-01

    Uprighting a tipped molar by using an uprighting spring is a fundamental orthodontic treatment technique. Following a weak anchorage done only by the anterior teeth the permanent lower second molar will rotate around its center of resistance, and besides the distalizing movement will occur its extrusion. Following the reaction, the mandibular anterior teeth will have a movement of intrusion. All these elements will lead to anterior open bite. Correction of vertical problems has become easier with the advent of mini-implants. U.I patient aged 24 years presenting for aesthetic and functional disorders. Clinical examination reveals intraoral Class I molar malocclusion on the right sight, upper narrowing arch with a slight overbite, and the both permanent first molars on the left side lost prematurely. The tooth 37 is inclined at 600 degrees to the plane of occlusion. To avoid front opening occlusion we used an orthodontic miniscrew inserted between the canine and the first premolar on the same side to achieve the second molar up righting. Lower second molar uprighting was achieved without unwanted movements in anterior mandibular region and without molar extrusion. Using mini implants in uprighting a tipped molar will achieve the desired tooth movement and will reduce the number of unwanted side effects and eventually to improve patient's esthetics.

  3. Molar volume of eutectic solvents as a function of molar composition and temperature☆

    Institute of Scientific and Technical Information of China (English)

    Farouq S. Mjalli

    2016-01-01

    The conventional Rackett model for predicting liquid molar volume has been modified to cater for the effect of molar composition of the Deep Eutectic Solvents (DES). The experimental molar volume data for a group of commonly used DES has been used for optimizing the improved model. The data involved different molar compositions of each DES. The validation of the new model was performed on another set of DESs. The average relative deviation of the model on the training and validation datasets was approximately 0.1%while the Rackett model gave a relative deviation of more than 1.6%. The modified model deals with variations in DES molar com-position and temperature in a more consistent way than the original Rackett model which exhibits monotonic performance degradation as temperature moves away from reference conditions. Having the composition of the DES as a model variable enhances the practical utilization of the predicting model in diverse design and process simulation applications.

  4. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany structures. This ratio comes from Fibonacci numbers.In this article, we explore this ...

  5. Golden Ratio

    Indian Academy of Sciences (India)

    Keywords. Fibonacci numbers, golden ratio, Sanskrit prosody, solar panel. Abstract. Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany ...

  6. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is sym- metrical and in proportion. If a face or a structure is in pro- portion, we are more likely to notice it and find it beautiful. The universal ratio of beauty is the 'Golden Ratio', found in many structures. This ratio comes from Fibonacci numbers. In this article, we explore this ...

  7. The contemporary management of third molars.

    Science.gov (United States)

    Hyam, D M

    2018-03-01

    The management of third molars requires a significant assessment and decision process both for the patient and the clinician. The clinician must always identify the indication for third molar surgery, assess the risks of the proposed procedure, and then modify their plan to account for the patient's current and future health, their social and financial setting, and the patient's tolerance of risk. In doing this, the clinician can tailor a solution to meet the individual patient's needs. This decision to remove a third molar is made in the fluid setting of the patient's quality of life and requires regular review. This article gives the clinician the tools, the matrix, and the confidence to guide patients through this process, and outlines some of the pitfalls and common points of bias within the process. © 2018 Australian Dental Association.

  8. Loss of the First Permanent Molar: Risk Factors and Adolescent Oral Health

    Directory of Open Access Journals (Sweden)

    Daraí Bárbara Sánchez Montero

    2017-02-01

    Full Text Available Foundation: the replacement of the primary dentition begins with the eruption of the first permanent molars that will be subjected to various risk factors.Objective: to determine the existing relation between the first permanent molar loss and the risk factors in adolescents from 12 to 14 years old. Method: a cross descriptive study was developed between October 20011 and March 2012. On a universe of 560 students, a simple random sampling was done and a sample of 185 patients was selected. On school visits dental exams were performed to determine the Clune index dental caries index, filled and missing teeth and the simplified index of oral hygiene. The estimated relative risk was used with prevalence odd ratio and prevalence ratio was calculated. The studied variables were: sex, oral hygiene habits, and habits of cariogenic diet bucodental health. Results: the loss of the first permanent molar predominated in the male sex with a 14.1 %. The prevailing risk factor was cariogenic diet which affected 57.3 of the population, where 80.6 of those who had a high consumption showed loss of the first permanent molar. Clune index (53,4 % in the female and 40 % in the male sex, dental caries, filled and lost teeth (1.7 % in female and 2.9 in the male sex were calculated. Conclusion: there is a direct relation between risk factors, poor oral hygiene and cariogenic feeding with the loss of the first permanent molar.

  9. Preformed crowns for decayed primary molar teeth.

    Science.gov (United States)

    Innes, Nicola P T; Ricketts, David; Chong, Lee Yee; Keightley, Alexander J; Lamont, Thomas; Santamaria, Ruth M

    2015-12-31

    measured in the studies: time to restoration failure or retreatment, patient satisfaction and costs. Crowns versus fillingsAll studies in this comparison used PMCs. One study reported outcomes in the short term and found no reports of major failure or pain in either group. There was moderate quality evidence that the risk of major failure was lower in the crowns group in the long term (risk ratio (RR) 0.18, 95% confidence interval (CI) 0.06 to 0.56; 346 teeth in three studies, one conventional and two using Hall Technique). Similarly, there was moderate quality evidence that the risk of pain was lower in the long term for the crown group (RR 0.15, 95% CI 0.04 to 0.67; 312 teeth in two studies).Discomfort associated with the procedure was lower for crowns fitted using the Hall Technique than for fillings (RR 0.56, 95% CI 0.36 to 0.87; 381 teeth) (moderate quality evidence).It is uncertain whether there is a clinically important difference in the risk of gingival bleeding when using crowns rather than fillings, either in the short term (RR 1.69, 95% CI 0.61 to 4.66; 226 teeth) or long term (RR 1.74, 95% CI 0.99 to 3.06; 195 teeth, two studies using PMCs with conventional technique at 12 months) (low quality evidence). Crowns versus non-restorative caries treatmentOnly one study compared PMCs (fitted with the Hall Technique) with non-restorative caries treatment; the evidence quality was very low and we are therefore we are uncertain about the estimates. Metal crowns versus aesthetic crownsOne split-mouth study (11 participants) compared PMCs versus aesthetic crowns (stainless steel with white veneers). It provided very low quality evidence so no conclusions could be drawn. Crowns placed on primary molar teeth with carious lesions, or following pulp treatment, are likely to reduce the risk of major failure or pain in the long term compared to fillings. Crowns fitted using the Hall Technique may reduce discomfort at the time of treatment compared to fillings. The amount and

  10. Sex ratios

    OpenAIRE

    West, Stuart A; Reece, S E; Sheldon, Ben C

    2002-01-01

    Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so ...

  11. External and internal anatomy of mandibular molars.

    Science.gov (United States)

    Rocha, L F; Sousa Neto, M D; Fidel, S R; da Costa, W F; Pécora, J D

    1996-01-01

    The external and internal anatomy of 628 extracted, mandibular first and second molars was studied. The external anatomy was studied by measuring each tooth and by observing the direction of the root curvatures from the facial surface. The internal anatomy of the pulp cavity was studied by a method of making the teeth translucent.

  12. Validity of scoring caries and primary molar hypomineralization (DMH) on intraoral photographs.

    Science.gov (United States)

    Elfrink, M E C; Veerkamp, J S J; Aartman, I H A; Moll, H A; Ten Cate, J M

    2009-11-01

    The aims of this study were to assess whether intraoral photographs could be used to score caries and hypomineralization on primary molars (Using adapted Molar Incisor Hypomineralization (MIH)-criteria), and also to assess the reliability and validity in 3-7 year-old Dutch children of these scores by comparing them to direct clinical scorings. Cross-sectional study. In this study 62 children (38.7% girls) with a mean age of 4.96 years (SD 1.27) participated. The children were rated clinically by their own dentist (authors JV or ME) for caries reaching the dentine in their primary molars (WHO criteria) and also for primary molar hypomineralization using the adapted MIH-criteria. For the intraoral photographs, a digital intraoral camera was used. The two paediatric dentists rated all the intraoral photographs on caries and hypomineralizations on the second primary molars, using the same criteria for the clinical scoring as for the scoring of the photographs. They scored independently, at least 2 weeks after the initial clinical scoring to avoid observational bias with the clinical scoring. This clinical observation was used as the gold standard from which sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and the Positive and Negative Likelihood Ratio were computed. To test the intra-observer agreement 25 % of the photographs were scored again, at least 2 weeks after the initial scoring of the images. Inter- and intra-observer agreement were tested using Cohen's Kappa. The mean prevalence of clinically detected caries at tooth level was 46.7% and the mean prevalence of clinically detected hypomineralizations in second primary molars at tooth level was 21.8%. The sensitivity of assessing caries using intraoral photographs was 85.5%, the specificity 83.6%, the positive likelihood ratio 5.2 and the negative likelihood ratio was 0.17. For Primary Molar Hypomineralization (DMH) the sensitivity was 72.3%, the specificity 92.8%, the

  13. Variabilidad de las proporciones molares en poblaciones humanas: un abordaje empleando modelos del desarrollo y experimentales / Variability of molar proportions in human populations: insights from developmental models and experiments in mice

    Directory of Open Access Journals (Sweden)

    Lucas A. D´Addona

    2016-03-01

    experimental studies have not yet been integrated in the context of biological anthropology. In this sense, this paper proposes: a to evaluate the consistency between changes in molar proportions in human populations that exhibit a wide variation in tooth size and the predictions derived from an inhibitory cascade model of dental development, and b to analyze the effect of the systemic factors controlling the growth of the organism on the lower molars proportions using strains of Mus musculus. The crown area of the mandibular molars was estimated from the bucco-lingual and mesio-distal diameters. The results obtained for human populations showed that the pattern of variation in molar proportions is consistent with expectations derived from the inhibitory cascade model and that most groups exhibit a general trend towards molar size reduction in the antero-posterior direction. Also, a significant positive association between the total molar area and the molar ratios M2/M1 and M3/M1 was observed. In the experimental models, growth alteration caused by systemic factors (protein subnutrition and reduced growth hormone resulted in a reduction of total molar area associated with changes in molar proportions. The latter are consistent with an increased antero-posterior inhibition. Overall, these results suggest that alterations in the systemic factors that control molar area can produce changes in the proportion of activators and inhibitors, and contribute in turn to inter-population differentiation in molar proportions. Keywords: Inhibitory cascade model; dental size; experimental and comparative approach

  14. Human dental age estimation combining third molar(s) development and tooth morphological age predictors.

    Science.gov (United States)

    Thevissen, P W; Galiti, D; Willems, G

    2012-11-01

    In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development.

  15. An innovative technique to distalize maxillary molar using microimplant supported rapid molar distalizer

    Directory of Open Access Journals (Sweden)

    Meenu Goel

    2013-01-01

    Full Text Available Introduction: In recent years, enhancements in implants have made their use possible as a mode of absolute anchorage in orthodontic patients. In this paper, the authors have introduced an innovative technique to unilaterally distalize the upper left 1 st molar to obtain an ideal Class I molar relationship from a Class II existing molar relationship with an indigenous designed distalizer. Clinical Innovation: For effective unilateral diatalization of molar, a novel cantilever sliding jig assembly was utilized with coil spring supported by a buccally placed single micro implant. The results showed 3 mm of bodily distalization with 1 mm of intrusion and 2° of distal tipping of upper left 1 st molar in 1.5 months. Discussion: This appliance is relatively easy to insert, well-tolerated, and requires minimal patient cooperation compared to other present techniques of molar distalization. Moreover, it is particularly useful in cases that are Class II on one side and Class I on the other, with a minor midline discrepancy and nominal overjet. Patient acceptance level was reported to be within patients physiological and comfort limits.

  16. Mandibular molar crown-topography, a biological predisposing ...

    African Journals Online (AJOL)

    Mandibular molar crown-topography, a biological predisposing factor to development of caries – a post-mortem analysis of 2500 extracted lower permanent molars at the dental centre, University of Benin teaching hospital.

  17. Prevention of alveolar osteitis after third molar surgery: Comparative ...

    African Journals Online (AJOL)

    Prevention of alveolar osteitis after third molar surgery: Comparative study of the ... for surgical extraction of lower third molar were prospectively, consecutively, and ... Information on demographic, types and level of impaction, indications for ...

  18. Variant Root Morphology of Third Mandibular Molar in Normal and ...

    African Journals Online (AJOL)

    isaac kipyator

    2017-11-12

    Nov 12, 2017 ... ABSTRACT. The mandibular third molar poses a challenge to dental surgeons due to it's unpredictable morphology ... treatment in the School of Dental Sciences since 2010. ... mandibular third molar include presence of three.

  19. Efficacy and safety of combined piroxicam, dexamethasone, orphenadrine, and cyanocobalamin treatment in mandibular molar surgery

    Directory of Open Access Journals (Sweden)

    Barroso A.B.

    2006-01-01

    Full Text Available Third molar extraction is a common procedure frequently accompanied by moderate or severe pain, and involves sufficient numbers of patients to make studies relatively easy to perform. The aim of the present study was to determine the efficacy and safety of the therapeutic combination of 10 mg piroxicam, 1 mg dexamethasone, 35 mg orphenadrine citrate, and 2.5 mg cyanocobalamin (Rheumazin® when compared with 20 mg piroxicam alone (Feldene® in mandibular third molar surgery. Eighty patients scheduled for removal of the third molar were included in this randomized and double-blind study. They received (vo Rheumazin or Feldene 30 min after tooth extraction and once daily for 4 consecutive days. Pain was determined by a visual analogue scale and by the need for escape analgesia (paracetamol. Facial swelling was evaluated with a measuring tape and adverse effects and patient satisfaction were recorded. There was no statistically significant difference in facial swelling between Rheumazin and Feldene (control group. Both drugs were equally effective in the control of pain, with Rheumazin displaying less adverse effects than Feldene. Therefore, Rheumazin appears to provide a better risk/benefit ratio in the mandibular molar surgery. Since the side effects resulting from nonsteroidal anti-inflammatory drug administration are a severe limitation to the routine use of these drugs in clinical practice, our results suggest that Rheumazin can be a good choice for third molar removal treatment.

  20. Efficacy and safety of combined piroxicam, dexamethasone, orphenadrine, and cyanocobalamin treatment in mandibular molar surgery

    Directory of Open Access Journals (Sweden)

    A.B. Barroso

    Full Text Available Third molar extraction is a common procedure frequently accompanied by moderate or severe pain, and involves sufficient numbers of patients to make studies relatively easy to perform. The aim of the present study was to determine the efficacy and safety of the therapeutic combination of 10 mg piroxicam, 1 mg dexamethasone, 35 mg orphenadrine citrate, and 2.5 mg cyanocobalamin (Rheumazin® when compared with 20 mg piroxicam alone (Feldene® in mandibular third molar surgery. Eighty patients scheduled for removal of the third molar were included in this randomized and double-blind study. They received (vo Rheumazin or Feldene 30 min after tooth extraction and once daily for 4 consecutive days. Pain was determined by a visual analogue scale and by the need for escape analgesia (paracetamol. Facial swelling was evaluated with a measuring tape and adverse effects and patient satisfaction were recorded. There was no statistically significant difference in facial swelling between Rheumazin and Feldene (control group. Both drugs were equally effective in the control of pain, with Rheumazin displaying less adverse effects than Feldene. Therefore, Rheumazin appears to provide a better risk/benefit ratio in the mandibular molar surgery. Since the side effects resulting from nonsteroidal anti-inflammatory drug administration are a severe limitation to the routine use of these drugs in clinical practice, our results suggest that Rheumazin can be a good choice for third molar removal treatment.

  1. First molar cross-bite is more closely associated with a reverse chewing cycle than anterior or pre-molar cross-bite during mastication.

    Science.gov (United States)

    Tomonari, H; Ikemori, T; Kubota, T; Uehara, S; Miyawaki, S

    2014-12-01

    A posterior cross-bite is defined as an abnormal bucco-lingual relationship between opposing molars, pre-molars or both in centric occlusion. Although it has been reported that patients with unilateral posterior cross-bite often show unique chewing patterns, the relationship between the form of cross-bite and masticatory jaw movement remains unclear in adult patients. The objective of this study was to investigate masticatory jaw movement among different forms of cross-bite. One hundred and one adults were recruited in this study: 27 had unilateral first molar cross-bite (MC group); 28, unilateral pre-molar cross-bite (PC group); 23, anterior cross-bite (AC group); and 23, normal occlusion (control group). Masticatory jaw movement of the lower incisor point was recorded with six degrees of freedom jaw-tracking system during unilateral mastication. Our results showed that the reverse chewing ratio during deliberate unilateral mastication was significantly larger in the MC group than in the PA (P chewing cycle. © 2014 John Wiley & Sons Ltd.

  2. Molar incisor hypomineralization: current research evidences

    Directory of Open Access Journals (Sweden)

    Manikandan Ekambaram

    2016-06-01

    Full Text Available Molar-Incisor Hypomineralization (MIH is a condition of systemic origin that involves one to four first permanent molar teeth and often associated with affected incisors. Although several associations to prenatal/perinatal childhood medical conditions have been reported, the etiology of MIH still remains unclear. The degree of enamel hypomineralization in the affected teeth can vary and the clinical problems associated with the teeth include increased susceptibility to caries, rapid wear, and post-eruptive enamel breakdown. Affected teeth are extremely challenging to treat as the enamel is porous, sensitive and treating clinicians might encounter great difficulty in achieving profound anaesthesia. The first part of thispresentation will give an update on prevalence, potential etiological factors, and management strategies of this condition. The second part of the presentation will cover a systematic review results on bonding strategies to hypomineralized enamel.

  3. [Delayed wound healing post molar extraction].

    Science.gov (United States)

    Schepers, R H; De Visscher, J G A M

    2009-02-01

    One month post extraction of the second left maxillary molar the alveolar extraction site showed no signs of healing and was painful. The patient had been using an oral bisphosphonate during 3 years. Therefore, the lesion was diagnosed as bisphosphonate-induced maxillary osteonecrosis. Treatment was conservative. Since one month later the pain had increased and the wound healing had decreased, a biopsy was carried out. Histopathologic examination revealed a non-Hodgkin lymphoma.

  4. Enamel micromorphology of the tribosphenic molar

    OpenAIRE

    Hanousková, Pavla

    2014-01-01

    The tribosphenic molar is an ancestral type of mammalian teeth and a phy- lotypic stage of the mammalian dental evolution. Yet, in contrast to derived teeth types, its enamel microarchitecture attracted only little attention and the information on that subject is often restricted to statements suggesting a simple homogenous arrangement of a primitive radial prismatic enamel. The present paper tests this prediction with aid of comparative study of eight model species representing the orders Ch...

  5. Incidence of lower second permanent molar impaction.

    Science.gov (United States)

    Evans, R

    1988-08-01

    The incidence of lower second molar impaction was investigated, comparing the records of two samples of 200 orthodontic patients referred consecutively, in 1976 and 1986. A further study compared 50 cases showing both bilateral and unilateral impactions, with a non-impacted control group. This allowed possible causes of the impactions to be examined, particularly concerning the effect of premature loss of deciduous teeth on the distribution of crowding.

  6. Three-dimensional primate molar enamel thickness.

    Science.gov (United States)

    Olejniczak, Anthony J; Tafforeau, Paul; Feeney, Robin N M; Martin, Lawrence B

    2008-02-01

    Molar enamel thickness has played an important role in the taxonomic, phylogenetic, and dietary assessments of fossil primate teeth for nearly 90 years. Despite the frequency with which enamel thickness is discussed in paleoanthropological discourse, methods used to attain information about enamel thickness are destructive and record information from only a single plane of section. Such semidestructive planar methods limit sample sizes and ignore dimensional data that may be culled from the entire length of a tooth. In light of recently developed techniques to investigate enamel thickness in 3D and the frequent use of enamel thickness in dietary and phylogenetic interpretations of living and fossil primates, the study presented here aims to produce and make available to other researchers a database of 3D enamel thickness measurements of primate molars (n=182 molars). The 3D enamel thickness measurements reported here generally agree with 2D studies. Hominoids show a broad range of relative enamel thicknesses, and cercopithecoids have relatively thicker enamel than ceboids, which in turn have relatively thicker enamel than strepsirrhine primates, on average. Past studies performed using 2D sections appear to have accurately diagnosed the 3D relative enamel thickness condition in great apes and humans: Gorilla has the relatively thinnest enamel, Pan has relatively thinner enamel than Pongo, and Homo has the relatively thickest enamel. Although the data set presented here has some taxonomic gaps, it may serve as a useful reference for researchers investigating enamel thickness in fossil taxa and studies of primate gnathic biology.

  7. Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

    NARCIS (Netherlands)

    Livas, Christos; Pandis, Nikolaos; Booij, Johan Willem; Halazonetis, Demetrios J.; Katsaros, Christos; Ren, Yijin

    Objective: To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction. Materials and Methods: Panoramic radiographs of 21 Class II subdivision adolescents (eight

  8. One year Survival Rate of Ketac Molar versus Vitro Molar for Occlusoproximal ART Restorations: a RCT

    Directory of Open Access Journals (Sweden)

    PACHECO Anna Luisa de Brito

    2017-11-01

    Full Text Available Abstract Good survival rates for single-surface Atraumatic Restorative Treatment (ART restorations have been reported, while multi-surface ART restorations have not shown similar results. The aim of this study was to evaluate the survival rate of occluso-proximal ART restorations using two different filling materials: Ketac Molar EasyMix (3M ESPE and Vitro Molar (DFL. A total of 117 primary molars with occluso-proximal caries lesions were selected in 4 to 8 years old children in Barueri city, Brazil. Only one tooth was selected per child. The subjetcs were randomly allocated in two groups according to the filling material. All treatments were performed following the ART premises and all restorations were evaluated after 2, 6 and 12 months. Restoration survival was evaluated using Kaplan-Meier survival analysis and Log-rank test, while Cox regression analysis was used for testing association with clinical factors (α = 5%. There was no difference in survival rate between the materials tested, (HR = 1.60, CI = 0.98–2.62, p = 0.058. The overall survival rate of restorations was 42.74% and the survival rate per group was Ketac Molar = 50,8% and Vitro Molar G2 = 34.5%. Cox regression test showed no association between the analyzed clinical variables and the success of the restorations. After 12 months evaluation, no difference in the survival rate of ART occluso-proximal restorations was found between tested materials.

  9. Radiologic study of mandibular third molar of Korean youths

    International Nuclear Information System (INIS)

    Ahn, Hyung Kyu

    1982-01-01

    The author has made a study on the classification of the mandibular 3rd molars of Korean youths through dental radiography by means of Pell and Gregory's classification and on the prevalence of the dental caries of distal surface of the mandibular 2nd molar adjacent to the mandibular 3rd molars turned anteriorly. The results are as follow; 1. It was found that the largest case number was class I (272 cases, 52.9%) in the relation of the tooth to the ramus of the mandible and 2nd molar. 2. The mesio-angular position was the largest number (239 cases, 46.5%) in the relation of the long axis of the impacted mandibular 3rd molar to the long axis of the 2nd molar. 3. The mesio-angular position of class I was the largest number (140 cases, 27.2%) in the relation of the tooth to the ramus of the mandible and 2nd molar and the long axis of the impacted mandibular 3rd moral to the long axis of the 2nd molar. 4. The average angle of the long axis of mandibular 3rd molar in mesioangular position or horizontal position to the occlusal plane was 143 W 5. Mandibular 3rd molar with lesion such as dental cries or pericoronitis was 73 cases (14.2). 6. The caries incidence rate of the distal surface of the 2nd molar was about 3.1%.

  10. Bilateral lower second molar impaction in teenagers: An emergent problem?

    Directory of Open Access Journals (Sweden)

    Shinohara Elio

    2010-01-01

    Full Text Available The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impacted third molar for the eruption of the second molar through a vestibular incision. This incision offers excellent bone exposure and exit route for the third molar without disturbing the gingiva attached architecture on the distal face of the first molar providing good healing environment.

  11. Are Hypomineralized Primary Molars and Canines Associated with Molar-Incisor Hypomineralization?

    Science.gov (United States)

    da Silva Figueiredo Sé, Maria Jose; Ribeiro, Ana Paula Dias; Dos Santos-Pinto, Lourdes Aparecida Martins; de Cassia Loiola Cordeiro, Rita; Cabral, Renata Nunes; Leal, Soraya Coelho

    2017-11-01

    The purpose of this study was to evaluate the prevalence of and relationship between hypomineralized second primary molars (HSPM) and hypomineralized primary canines (HPC) with molar-incisor hypomineralization (MIH) in 1,963 schoolchildren. The European Academy of Paediatric Dentistry (EAPD) criterion was used for scoring HSPM/HPC and MIH. Only children with four permanent first molars and eight incisors were considered in calculating MIH prevalence (n equals 858); for HSPM/HPC prevalence, only children with four primary second molars (n equals 1,590) and four primary canines (n equals 1,442) were considered. To evaluate the relationship between MIH/HSPM, only children meeting both criteria cited were considered (n equals 534), as was true of MIH/HPC (n equals 408) and HSPM/HPC (n equals 360; chi-square test and logistic regression). The prevalence of MIH was 14.69 percent (126 of 858 children). For HSPM and HPC, the prevalence was 6.48 percent (103 of 1,592) and 2.22 percent (32 of 1,442), respectively. A significant relationship was observed between MIH and both HSPM/HPC (PMIH based on HSPM was 6.31 (95 percent confidence interval [CI] equals 2.59 to 15.13) and for HPC was 6.02 (95 percent CI equals 1.08 to 33.05). The results led to the conclusion that both hypomineralized second primary molars and hypomineralized primary canines are associated with molar-incisor hypomineralization, because children with HSPM/HPC are six times more likely to develop MIH.

  12. MANAGEMENT OF MANDIBULAR THIRD MOLAR SURGERY TO PRESERVE PERIODONTAL HEALTH OF SECOND MOLAR

    Directory of Open Access Journals (Sweden)

    Elitsa G. Deliverska

    2017-06-01

    Full Text Available Background: Extraction of impacted third molar violates surrounding soft and bony tissues. Various surgical approaches and surgical technics have an important impact on the periodontal health of the adjacent second molar. Purpose: The aim of this review is to analyse the causes that can affect postoperative periodontal outcomes for the mandibular second molars (LM2 adjacent to the impacted/ semi impacted mandibular third molars (LM3. Material and Methods: Electronic searches were conducted through the MEDLINE (PubMed, Scopus, etc. databases to screen all relevant articles published from inception to April 2017. Results: Different flap techniques had no significant impact on the probing depth reduction or on the clinical attachment level of LM2. Szmyd and paramarginal flap designs may be the most effective in reducing the probing depth after third molar surgery, and the envelope flap may be the least effective. Use of bone substitutes and guided tissue regeneration therapy has been proposed, to eliminate or prevent these periodontal defects, but there is still no consensus on their predictability or clinical benefit. Higher costs and the risk of postoperative inflammatory complications should also be taken into proper account, as with any surgical procedure. “Orthodontic extraction” is indicated for that impacted M3 that present a high risk of postoperative periodontal defects at the distal aspect of adjacent M2. Conclusion: Risk factors associated with bone loss following lower third molar extraction includes age, the direction of the eruption, preoperative bone defects, and resorbtion of the LM2 root surface. Prevention of such periodontal defects continues to challenge clinicians.

  13. Mandibular molar with five root canals.

    Science.gov (United States)

    Barletta, Fernando Branco; Dotto, Sidney Ricardo; Reis, Magda de Sousa; Ferreira, Ronise; Travassos, Rosana Maria Coelho

    2008-12-01

    The purpose of this study was to demonstrate the importance of knowledge of the internal anatomy of root canals for the success of endodontic treatment. Lack of knowledge of anatomic variations and their characteristics in different teeth has been pointed out as one of the main causes of endodontic therapy failure. In this report, the authors describe the endodontic treatment of a mandibular first molar with five root canals, evaluate the rate of occurrence of this number of canals, and discuss the importance of their identification and treatment.

  14. Root growth during molar eruption in extant great apes.

    Science.gov (United States)

    Kelley, Jay; Dean, Christopher; Ross, Sasha

    2009-01-01

    While there is gradually accumulating knowledge about molar crown formation and the timing of molar eruption in extant great apes, very little is known about root formation during the eruption process. We measured mandibular first and second molar root lengths in extant great ape osteological specimens that died while either the first or second molars were in the process of erupting. For most specimens, teeth were removed so that root lengths could be measured directly. When this was not possible, roots were measured radiographically. We were particularly interested in the variation in the lengths of first molar roots near the point of gingival emergence, so specimens were divided into early, middle and late phases of eruption based on the number of cusps that showed protein staining, with one or two cusps stained equated with immediate post-gingival emergence. For first molars at this stage, Gorilla has the longest roots, followed by Pongo and Pan. Variation in first molar mesial root lengths at this stage in Gorilla and Pan, which comprise the largest samples, is relatively low and represents no more than a few months of growth in both taxa. Knowledge of root length at first molar emergence permits an assessment of the contribution of root growth toward differences between great apes and humans in the age at first molar emergence. Root growth makes up a greater percentage of the time between birth and first molar emergence in humans than it does in any of the great apes. Copyright (c) 2009 S. Karger AG, Basel.

  15. Taking advantage of an unerupted third molar: a case report

    Directory of Open Access Journals (Sweden)

    Igor Figueiredo Pereira

    Full Text Available ABSTRACT Introduction: Treatments with dental surgery seek to displace tooth to the correct position within the dental arch. Objective: To report a clinical case that took advantage of an unerupted third molar. Case history: A male patient, 18 years of age, was referred by his dentist to evaluate the third molars. The clinical exam revealed no visible lower third molars. The computed tomography (CT exam showed the presence of a supernumerary tooth in the region of the mandibular ramus, on the left side, and impaction of the third molar, which was causing root resorption on the second molar, thus making it impossible to remain in the buccal cavity. The preferred option, therefore, was to remove both second molar and the supernumerary tooth, in addition to attaching a device to the third molar during surgery for further traction. Results: After 12 months, the third molar reached the proper position. Conclusion: When a mandibular second permanent molar shows an atypical root resorption, an impacted third molar can effectively substitute the tooth by using an appropriate orthodontic-surgical approach.

  16. Molar Incisor Hypomineralization, Prevalence, and Etiology

    Directory of Open Access Journals (Sweden)

    Sulaiman Mohammed Allazzam

    2014-01-01

    Full Text Available Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n=267  from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM, erupted or partially erupted. Demographic information, children’s medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB, atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P=0.01. The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P=0.001, adenoiditis (P=0.001, asthma (P=0.001, fever (P=0.014, and antibiotics intake (P=0.001. Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake.

  17. Onset of molar incisor hypomineralization (MIH).

    Science.gov (United States)

    Fagrell, Tobias G; Salmon, Phil; Melin, Lisa; Norén, Jörgen G

    2013-01-01

    The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age.

  18. Sealing Occlusal Dentin Caries in Permanent Molars

    DEFF Research Database (Denmark)

    Qvist, Vibeke; Borum, Mette Kit; Møller, Kirsten Dynes

    2017-01-01

    The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical and radiog......The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical...... longevity of sealings and restorations until retreatments, and 3) compare effectiveness of sealings and restorations to halt caries progression in sealed lesions and beneath restorations. Furthermore, we aimed to identify factors influencing longevity and the effectiveness of sealings and restorations.......001). The median survival time for sealings not replaced by restorations was 7.3 y (CI, 6.4 y to NA). Survival of sealings was increased in patients with low caries risk and/or excellent oral hygiene, second molars compared with first molars, and lesions not extending the middle one-third of the dentin. Survival...

  19. Extrações de molares na Ortodontia Molar extractions in orthodontics

    Directory of Open Access Journals (Sweden)

    Marco Antônio Schroeder

    2011-12-01

    Full Text Available O tratamento ortodôntico com extração de molares em pacientes adultos é tecnicamente mais complexo, devido a inúmeros fatores. Em geral, o espaço a ser fechado é maior do que o espaço dos pré-molares e, por isso, a ancoragem é crítica e o tempo de tratamento mais longo. É comum esses casos apresentarem algum grau de comprometimento periodontal por causa da idade dos pacientes e, portanto, necessitam de maior controle da mecânica ortodôntica para reduzir os efeitos colaterais do fechamento do espaço. Por isso, bons resultados de finalização são mais difíceis de ser alcançados. Sendo assim, este artigo tem como objetivo apresentar as razões para a indicação de extração de molares nos tratamentos ortodônticos, as contraindicações, as diferentes fases da mecânica ortodôntica, esclarecer os fatores envolvidos nesse tipo de planejamento e tratamento e apresentar casos clínicos tratados com extração de molares.Orthodontic treatment with extraction of molars in adult patients is technically more complex due to a number of factors. In general, the space to be closed is greater than premolar spaces rendering critical anchorage and longer treatment time. Often such cases exhibit some degree of periodontal involvement due to patient age. Hence, the need for greater control over orthodontic mechanics to reduce the side effects of space closure. Therefore, good finishing results can be more difficult to achieve. Thus, the purpose of this article is to determine the reasons for molar extraction indications, describe different stages of orthodontic mechanics, and explain the issues involved in this kind of planning and treatment. Additionally, it aims at describing some treatments with molar extractions.

  20. Autotransplantation of Mandibular Third Molar: A Case Report

    Directory of Open Access Journals (Sweden)

    Pabbati Ravi kumar

    2012-01-01

    Full Text Available Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38 without anatomical variances is used to replace a mandibular left second molar (37. The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

  1. Survival of sealants in molars affected by molar-incisor hypomineralization: 18-month follow-up

    Directory of Open Access Journals (Sweden)

    Camila Maria Bullio FRAGELLI

    2017-04-01

    Full Text Available Abstract The objective of this study was to evaluate the clinical survival of sealants applied in first permanent molars (FPMs affected by molar-incisor hypomineralization (MIH, at 18 months of follow-up. Forty-one first permanent molars were selected from 21 children, 6–8 years of age. MIH was classified by one calibrated examiner (kappa = 0.80 according to EAPD criteria. The inclusion criteria were fully erupted FPMs with MIH or sound FPMs (without MIH for which sealant treatment was indicated. The FPMs were assigned to two groups: CG (control group and HG (MIH group. Both groups were treated with sealant (FluroShield. Clinical follow-up was performed from baseline to 18 months to assess anatomical form, marginal adaptation, retention and presence of caries, according to criteria set by the United States Public Health Service-Modified, and was conducted by a blinded examiner (kappa = 0.80. The actuarial method was used to evaluate the survival of the sealants. The survival rates for the groups were compared using Fisher’s exact test (α = 5%. The cumulative survival rates were 81% at 1 month, 68.8% at 6 months, 68.8% at 12 months, and 62.6% at 18 months for CG, and 88% at 1 month, 84% at 6 months, 76% at 12 months, and 72% at 18 months for HG. No significant difference was found between the groups. The sealants in molars affected by MIH presented a survival rate similar to the sealants in the control, suggesting that sealants may be an adequate approach for preventing carious lesions in MIH-affected molars.

  2. Unusal canal configuration in maxillary and mandibular second molars

    Directory of Open Access Journals (Sweden)

    Ramachandran Ragunathan

    2016-01-01

    Full Text Available This clinical article describes three different case reports of maxillary and mandibular second molars with the unusual anatomy of single root with a single canal and their endodontic management. An unusual case of bilateralism is observed in the first two cases in the form of single-rooted second mandibular molars in both the quadrant of the same patient. The presence of maxillary second molar with single root and single canal in the third case is unusual.

  3. [Orthodontic Management of the Impacted Mandibular Second Molar Tooth].

    Science.gov (United States)

    Mah, Michael; Takada, Kenji

    2016-09-01

    When the mandibular permanent second molar becomes impacted, it is identified as a malocclusion that needs treatment as it often leads to unwanted complications such as caries and periodontitis of the adjacent permanent first molar. Other less common complications include root resorption of the adjacent first molar root or continued root development to be in close proximity to the inferior dental alveolar nerve. This paper seeks to differentiate various levels of severity of impaction and review treatment options that are considered clinically available for the proper management of the impacted mandibular permanent second molar. Treatment options that will be discussed in this article include timing of second molar removal for replacement by the third molar, relief of impaction via second premolar removal, surgical repositioning and the combination of third molar removal, surgical exposure and orthodontic uprighting of the impacted tooth. Depending on the severity of the impaction, most impactions can be easily and predictably corrected with nickel titanium archwires or auxillary open coil springs or uprighting springs. Uncommonly, the mandibular permanent second molar can become severely impacted and in close proximity to the inferior dentoalveolar nerve. In these instances, the use of temporary anchorage devices such as microimplants has shown to be successful in uprighting the severely impacted mandibular permanent second molars. © EDP Sciences, SFODF, 2016.

  4. Epidemiological Status of Third Molars in an Iranian Population

    Directory of Open Access Journals (Sweden)

    Mahnaz Sheikhi

    2016-07-01

    Full Text Available Background Impaction of third molars is a common phenomenon. The incidence of impacted third molars varies in different populations. Objectives The aim of this study is to assess radiographic status (root development degree, angulation, and eruption level of the third molar in Iranian population via panoramic radiographs. Patients and Methods 647 patients, ranging in age from 17 - 25, were selected from three regions of Iran. Based on their panoramic radiographs, their root development degree, angulation, and eruption levels were analyzed. Results The angulation of upper third molars were vertical (44.6%, distoangular (44.1%, mesioangular (10.7%, and horizontal (0.6%. For lower third molars, the angulation was mesioangular (44.5%, vertical (33.8%, distoangular (12.2%, and horizontal (9.5%. The eruption levels of maxillary third molars were C > A> B, and for mandibular third molars they were A > B> C. The order of root development prevalence of the maxillary and mandibular third molars was complete > 2/3 > 1/3. Conclusions The most common status of impaction of the third molars in the maxilla was vertical angulation, level C of eruption, and complete root formation. In the mandible it was mesioangular, level A of eruption, and complete root formation. Since the study sample consists of patients from the north, middle, and south of Iran, the sample can represent the whole population of Iran.

  5. Apparent molar volumes and compressibilities of selected electrolytes in dimethylsulfoxide

    International Nuclear Information System (INIS)

    Warminska, Dorota; Grzybkowski, Waclaw

    2010-01-01

    Densities at T = (293.15, 298.15, 303.15, 313.15, 323.15, and 333.15) K and sound velocities at T = 298.15 K of tetraphenylphosphonium bromide, sodium tetraphenylborate, sodium bromide, and sodium perchlorate in dimethylsulfoxide have been measured over the composition range from (0 to 0.3) mol . kg -1 . From these data, apparent molar volumes and apparent molar isentropic compressibilities at infinite dilution as well as the expansibilities have been evaluated. The results have been discussed in terms of employing tetraphenylphosphonium tetraphenylborate as a reference electrolyte in splitting the limiting apparent molar volumes and apparent molar isentropic compressibilities into ionic contributions.

  6. Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years.

    Science.gov (United States)

    Syed, Kamran Bokhari; Zaheer, Kamran Bokhari; Ibrahim, Mohammed; Bagi, Mustafa Abdel; Assiri, Mohammed Abdullah

    2013-02-01

    To report the prevalence of impacted third molars according to the age, gender and type among Saudi population. This retrospective study involved 3800 panoramic radiographs of subjects aged 18 to 45 years who presented to the College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia for oral care during the period from February 2009 to February 2011. Data collected was entered into a spreadsheet (Excel 2000; Microsoft, US) and analyzed using Statistical Package for Social Sciences (SPSS) version 16.0. A total of 713 impacted teeth were identified (18.76%) (p=0.003). The male to female ratio with impacted third molars was 604:109 (5.54:1) and the ratio of patients with impacted teeth was (5:1). Age group 1 (i.e., 20 to 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Incidence of tooth impaction is higher in the mandible than in maxilla. Males had a higher incidence of third molar impaction as compared to the females. Highest incidence is found in the age group of 20-25 years. Mesio-angular impaction was the most predominant type. How to cite this article: Syed KB, Kota Z, Ibrahim M, Bagi MA, Assiri MA. "Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years". J Int Oral Health 2013; 5(1):43-47.

  7. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement......The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2...

  8. Ceramic onlay for endodontically treated mandibular molar

    Directory of Open Access Journals (Sweden)

    Roopadevi Garlapati

    2014-01-01

    Full Text Available Restoration of endodontically treated teeth is important for the success of endodontic treatment. In full coverage restorations, maximum amount of tooth structure is compromised, so as to conserve the amount of tooth structure partial coverage restorations, can be preferred. This case report is on fabrication of a conservative tooth colored restoration for an endodontically treated posterior tooth. A 22-year-old male patient presented with pain in the mandibular left first molar. After endodontic treatment, composite material was used as postendodontic restoration. The tooth was then prepared to receive a ceramic onlay and bonded with self-adhesive universal resin cement. Ceramic onlay restoration was periodically examined up to 2 years.

  9. Presence of third molars in orthodontic patients from northern Greece

    Directory of Open Access Journals (Sweden)

    Barka G

    2012-05-01

    Full Text Available Georgia Barka,1 Georgios Tretiakov,1 Theodosios Theodosiou,2 Ioulia Ioannidou-Marathiotou31School of Dentistry, 2Biostatistics, Department of Informatics, School of Natural Sciences, 3Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, GreeceObjective: The purpose of the present study was to investigate the frequency of presence of third molar teeth and their distribution in each jaw and each side, according to sex, in a group of orthodontic patients with permanent dentition from northern Greece.Methods: The sample included panoramic radiographs from 220 patients with permanent dentition (mean age 13.62 ± 1.81. The Χ2 test was used to assess the relationships between the variables, and the Fisher's exact test was used in cases where the expected frequencies in each cell were <5.Results: The frequency of third molar presence was 79.1%, and 20.9% was the frequency of third molar agenesis. Intersexual differences in the number of third molars was not statistically significant. There was a correlation between the distribution of third molars on the right and the left side (Fisher's exact test = 100.788; P = 0. The two sides showed the same tendency toward the presence or absence of third molars. A correlation was also found between the distribution of maxillary and mandibular third molars (Fisher's exact test = 24.372; P = 0. In each jaw, the presence or absence of third molars was highly related to the number of third molars found in the other jaw.Conclusion: The present results showed that in this orthodontic group of northern Greek patients, presence accounted for 79.1% and agenesis for 20.9%. No significant difference was found between the frequencies of third molar presence on the left and right sides in either the maxilla or mandible.Keywords: third molars, presence, orthodontic population, Greeks

  10. Microleakage of different adhesive systems in primary molars ...

    African Journals Online (AJOL)

    Background and aim: This study aimed to examine the microleakage of class V cavities of primary molars prepared by either a conventional dental bur or Er:YAG laser and one of two different adhesive systems. Methods: A total of 50 tooth samples from primary molars were used in this study. They were randomly assigned ...

  11. Changes in heart rate during third molar surgery

    NARCIS (Netherlands)

    Hollander, M. H. J.; Schortinghuis, J.; Vissink, A.

    2016-01-01

    Anxiety is an undesirable psychological phenomenon. Patients are usually anxious when subjected to third molar surgery, but the pattern of anxiety is unknown. The aim of this study was to assess the intensity and course of anxiety during third molar surgery. This study included 48 consecutive

  12. Taurodont molars: Review of literature and radiological features

    International Nuclear Information System (INIS)

    Saini, T.; Wilson, C. A.

    1990-01-01

    Taurodontic molar teeth are present as a clinical entity in modem man. This is a suggestion that the occurrence has a racial bias. The importance of the differential diagnosis of teeth with enlarged pulp is discussed, and the possible influence of taurodontic molars on treatment planning is outlined. (author)

  13. Management of inflammatory complications in third molar surgery: A ...

    African Journals Online (AJOL)

    Background: Pain, swelling and trismus are common complications associated with third molar surgery. These complications have been reported to have an adverse effect on the quality of life of patients undergoing third molar surgery. Objective: To review the different modalities of minimizing inflammatory complications in ...

  14. Excess molar volumes and isentropic compressibilities of binary

    Indian Academy of Sciences (India)

    Excess molar volumes (E) and deviation in isentropic compressibilities (s) have been investigated from the density and speed of sound measurements of six binary liquid mixtures containing -alkanes over the entire range of composition at 298.15 K. Excess molar volume exhibits inversion in sign in one binary ...

  15. Molar incisor hypomineralisation: clinical management of the young patient.

    LENUS (Irish Health Repository)

    Daly, Dympna

    2009-04-01

    Molar incisor hypomineralisation (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. Early diagnosis is essential since rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its clinical management in young children.

  16. Association of the Mandibular Third Molar Position to the Pericoronitis

    Directory of Open Access Journals (Sweden)

    Tsvetan Tsvetanov

    2018-02-01

    Full Text Available Introduction: Pericoronitis is inflammation of the soft tissues surrounding the crown of a partially erupted tooth. Objective: To provide measurement of lower third molar angulation and determine relationship between mandibular third molar position and presence of pericoronitis. Material and methods: We studied 104 patients with lower third molar pericoronitis with clinical manifestations and measurement of lower third molar angulation. The mean age of patients was 25.7 years (range 18-35 years. Results: In this study was used the following statistical analysis, Pearson correlation coefficient and Spearman’s correlation coefficient (nonparametric version of the Pearson correlation coefficient for measure of the linear correlation between two variables - pericoronitis and angulation of the lower third molars. The chi-square test was used to assesses case incidences. The level of significance was p<0.05. 36.04% of partially impacted mandibular third molars were mesioangular followed by the vertical (25.47%, horizontal (18.97%, distoangular (9.21%, buccal (5.42% and lingual (3.79% position. The lowest part of the mandibular third molars is located in the ramus of mandible (1.08%. The present study was found in relation to mesioangular, distoangular, vertical impaction and pericoronitis (p<0.05. Conclusion: We conclude that the position of lower third molar may be able to be associated with presence of pericoronitis.

  17. Fatigue resistance of CAD/CAM resin composite molar crowns.

    NARCIS (Netherlands)

    Shembish, F.A.; Tong, H.; Kaizer, M.; Janal, M.N.; Thompson, V.P.; Opdam, N.J.M.; Zhang, Y.

    2016-01-01

    OBJECTIVE: To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. METHODS: Fully anatomically shaped monolithic resin composite molar crowns (Lava

  18. Variant root morphology of third mandibular molar in normal and ...

    African Journals Online (AJOL)

    The mandibular third molar poses a challenge to dental surgeons due to it's unpredictable morphology which leads to increased difficulty during its extraction. The root morphology of the third molar is considered to be the most variable in the human dentition. The study aims to document these variations which will be useful ...

  19. Prevalent of root resorption of second molar adjustment the impacted third molar in prepiacal and panoramic radiographs

    Directory of Open Access Journals (Sweden)

    Mohammad Ebrahimi Saravi

    2013-10-01

    Full Text Available   Background and Aims: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs.   Materials and Methods: In this cross-sectional descriptive study 54 patient (28 men, 26 women above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical, and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test.   Results: The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies, with respect to the limitation of the sample size were 46.3% and 31.5%, respectively, with 95% confidence(P>0.05. Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs.   Conclusion: Due to the increased risk of the resorption of the second molar adjacent to the third molar, extraction of the impacted third molars, especiall y mesially oriented or horizontal ones are recommended.

  20. Impacted third molar transplantation on the malpracticed extraction socket.

    Science.gov (United States)

    Kim, Soung Min; Amponsah, Emmanuel K

    2017-12-01

    Autotransplantation with or without endodontic therapy is regarded as an alternative treatment option for the replacement of missing teeth. A primary responsibility of a maxillofacial surgeon is to reverse any malpractice to promote successful outcomes and improve the patient's quality of life. This paper presents a malpractice case of incorrect extraction of the lower second molar instead of the impacted third molar. A simple technique of transplanting the impacted third molar to the site of the extracted second molar is introduced by a maxillofacial specialist in Ghana. By making an intentional root socket and fixation without using additional appliances, a novel second molar was achieved with complete recovery. This patient was followed after transplant for a four-year period with the best satisfaction. A grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea. (HI15C0689).

  1. PULPOTOMIES WITH PORTLAND CEMENT IN HUMAN PRIMARY MOLARS

    Science.gov (United States)

    Conti, Taísa Regina; Sakai, Vivien Thiemy; Fornetti, Ana Paula Camolese; Moretti, Ana Beatriz Silveira; Oliveira, Thais Marchini; Lourenço, Natalino; Machado, Maria Aparecida Andrade Moreira; Abdo, Ruy Cesar Camargo

    2009-01-01

    Two clinical cases in which Portland cement (PC) was applied as a medicament after pulpotomy of mandibular primary molars in children are presented. Pulpotomy using PC was carried out in two mandibular first molars and one mandibular second molar, which were further followed-up. At the 3, 6 and 12-month follow-up appointments, clinical and radiographic examinations of the pulpotomized teeth and their periradicular area revealed that the treatments were successful in maintaining the teeth asymptomatic and preserving pulpal vitality. Additionally, the formation of a dentin bridge immediately below the PC could be observed in the three molars treated. PC may be considered as an effective alternative for primary molar pulpotomies, at least in a short-term period. Randomized clinical trials with human teeth are required in order to determine the suitability of PC before unlimited clinical use can be recommended. PMID:19148409

  2. Angulation change of the third molar tooth in orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Ardiansyah S. Pawinru

    2017-04-01

    Full Text Available Objective : Impaction of the third molar tooth mandibular is often found in patients with orthodontic treatment. In orthodontic treatment, extraction cases of impaction of the third molar tooth are usually performed, but the patients often refuse this extraction. Extraction of premolar has a good effect on the third molar mandibular angulation during treatment. Material and Methods : This study is a retrospective clinical study with descriptive analytic to find out the effect of the first mandibular premolar tooth extraction to angulation change of the third molar mandibular in orthodontic treatment with a standard edgewise method. Angulation change was performed by comparing the third molar mandibular angulation before and after orthodontic treatment with panoramic radiographs. Angulation of the third molar tooth mandibular was calculated from the angle formed between the long axis of the tooth with the reference line infraorbita. Results : The sample comprised 60 of impacted mandibular third molar region of the left and right regions of 30 patients who had been treated declared cured in clinic of orthodontic specialist of Dentistry Faculty Padjadjaran University. The sample was divided into three (3 groups of patients before treatment angulation of the third molar tooth mandibular under 300, 300 to 600 and above 60o, then measured change of angulation and observed whether it increased, fixed or decreased. Results were analyzed by T- test and Wilcoxon test showed that there was a significant change in angulation of the third molar mandibular in orthodontic treatment with the first premolar tooth mandibular extraction. Conclusion : This study is that the first premolar tooth mandibular extraction affects the angulation of the third molar tooth mandibular after orthodontic treatment.

  3. Effect of OH/NCO molar ratio on properties of soy-based polyurethane networks

    Czech Academy of Sciences Publication Activity Database

    Petrovic, Z. S.; Zhang, W.; Zlatanic, A.; Lava, C. C.; Ilavský, Michal

    2002-01-01

    Roč. 10, 1/2 (2002), s. 5-12 ISSN 1566-2543 R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : soy * polyol * polyurethane Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.196, year: 2002

  4. Effect of ferrous/ferric ions molar ratio on reaction mechanism for ...

    Indian Academy of Sciences (India)

    Wintec

    Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan. MS received 25 ... methods, a mixed aqueous solution of Fe. 2+ ... (Quantum Design model MPMS) at a magnetic field of. 100 Oe ...

  5. Micro-computed Tomographic Analysis of Mandibular Second Molars with C-shaped Root Canals.

    Science.gov (United States)

    Amoroso-Silva, Pablo Andrés; Ordinola-Zapata, Ronald; Duarte, Marco Antonio Hungaro; Gutmann, James L; del Carpio-Perochena, Aldo; Bramante, Clovis Monteiro; de Moraes, Ivaldo Gomes

    2015-06-01

    The goal of the present study was to evaluate the morphometric aspects of the internal anatomy of the root canal system of mandibular second molars with C-shaped canals. Fifty-two extracted second mandibular molars with C-shaped canals, fused roots, and radicular grooves were selected from a Brazilian population. The samples were scanned with a micro-computed tomographic scanner at a voxel size of 19.6 μm. The root canal cross sections were recorded as C1, C2, C3, and C4 root canal configurations according to the modified Melton classification. Morphometric parameters, including the major and minor diameters of the root canals, the aspect ratio, the roundness, and the tridimensional configuration (merging, symmetric, and asymmetric), were evaluated. The 3-dimensional reconstruction images of the teeth indicated an even distribution within the sample. The analysis of the prevalence of the different cross-sectional configurations of the C-shaped molars revealed that these were predominantly of the C4 and C3 configurations (1 mm from the apex) and the C1 and C2 configurations in the cervical third. According to the morphometric parameters, the C1 and the distal aspect of the C2 configurations exhibited the lowest roundness values and higher values for the area, major diameter, and aspect ratio in the apical third. Mandibular molars with C-shaped root canals exhibited similar distributions of symmetric, asymmetric, and merging type canals. The C1 configuration and the distal aspect of the C2 configuration exhibited the highest area values, low roundness values, and large apical diameters. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Tooth Wear Inclination in Great Ape Molars.

    Science.gov (United States)

    Knight-Sadler, Jordan; Fiorenza, Luca

    2017-01-01

    Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorillagorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species. © 2017 S. Karger AG, Basel.

  7. Prevalence and severity of molar incisor hypomineralization in children aged 11-16 years of a city in Karnataka, Davangere

    Directory of Open Access Journals (Sweden)

    M Kirthiga

    2015-01-01

    Full Text Available Introduction: Molar incisor hypomineralization (MIH describes the clinical picture of hypomineralization of systemic origin affecting one or more first permanent molar. There is a rarity of prevalence studies in Indian population. Objectives: The main aim of this study was to investigate the prevalence of MIH in a population of South Indian children. Settings and Design: A cross-sectional epidemiological survey, included 2000 children aged 11-16 years chosen by stratified random sampling from government and private schools of Davangere, a city in South India. Materials and Methods: Evaluation of MIH and decayed, missing and filled teeth was carried out in these children by a calibrated examiner. The severity of hypomineralization was recorded according to the Wetzel and Reckel scale. Statistical Analysis: Chi-square test was used to analyze the categorical data. P ≤ 0.05 was considered for statistical significance. Results: About 8.9% of all examined children showed at least one ill-structured first permanent molar in terms of MIH. The male and female ratio was found to be 1:1.1. The decreasing order of occurrence of MIH affected teeth were permanent maxillary molars, maxillaryincisors, mandibular molars and the mandibular incisors. Conclusion: The prevalence of MIH in the permanent dentition of south Indian children was 8.9%. There is a need for a proper planned preventive and restorative program with regard to the increasing prevalence of MIH.

  8. The not-so-harmless maxillary primary first molar extraction.

    Science.gov (United States)

    Northway, W M

    2000-12-01

    Premature loss of primary molars has been associated with space loss and eruptive difficulties, especially when the loss occurs to the primary second molars and when it occurs early. This has not been thought to be the case for primary first molars. The author revisited 13 cases from an earlier study on the effects of premature loss of maxillary primary molars. These longitudinal cases were scrutinized, using serial panoramic radiographs, to explain the irregular response in terms of dental migration. The author presents two case reports. In the earlier study, the author used digitized study casts and the concept of D + E space--the space occupied by the primary first and second molars--to describe the dental migration that occurred after premature tooth loss. Using analysis of variance on data generated using an instrument capable of measuring in tenths of millimeters, the author produced findings regarding the amount of space loss, rate of space loss, effect of age at loss, amount of space regained at the time of replacement by the permanent tooth and effect on Angle's classification. Finally, the author created a simulation describing directional change; this revealed that the maxillary primary first molar loss resulted in a mesial displacement of the permanent canine during eruption. When the maxillary primary first molar is lost prematurely, the first premolar erupts in a more mesial direction than normal, as a result of the mesial incline of the primary second molar, and consumes the space of the permanent canine, which becomes blocked out. Rather than use a space maintainer after the premature loss of the maxillary primary first molar, the author suggests, clinicians can choose from a number of other options for preventing the first premolar from erupting too far in a mesial direction.

  9. A three-dimensional finite element analysis of molar distalization with a palatal plate, pendulum, and headgear according to molar eruption stage

    Science.gov (United States)

    Kang, Ju-Man; Park, Jae Hyun; Bayome, Mohamed; Oh, Moonbee; Park, Chong Ook; Mo, Sung-Seo

    2016-01-01

    Objective This study aimed to (1) evaluate the effects of maxillary second and third molar eruption status on the distalization of first molars with a modified palatal anchorage plate (MPAP), and (2) compare the results to the outcomes of the use of a pendulum and that of a headgear using three-dimensional finite element analysis. Methods Three eruption stages were established: an erupting second molar at the cervical one-third of the first molar root (Stage 1), a fully erupted second molar (Stage 2), and an erupting third molar at the cervical one-third of the second molar root (Stage 3). Retraction forces were applied via three anchorage appliance models: an MPAP with bracket and archwire, a bone-anchored pendulum appliance, and cervical-pull headgear. Results An MPAP showed greater root movement of the first molar than crown movement, and this was more noticeable in Stages 2 and 3. With the other devices, the first molar showed distal tipping. Transversely, the first molar had mesial-out rotation with headgear and mesial-in rotation with the other devices. Vertically, the first molar was intruded with an MPAP, and extruded with the other appliances. Conclusions The second molar eruption stage had an effect on molar distalization, but the third molar follicle had no effect. The application of an MPAP may be an effective treatment option for maxillary molar distalization. PMID:27668192

  10. Autotransplantation of a mandibular third molar: A case report

    Directory of Open Access Journals (Sweden)

    Elham Najafi

    2017-09-01

    Full Text Available Tooth autotransplantation defines as transition of one tooth from one position to another, in same individual. It is a biological procedure in which teeth have the potential to induce alveolar bone growth. It can be applied in patients before adolescence growth is finished. It significantly reduces time and cost compared to implants. Healing rapidly occurs and function is regained almost immediately. Our case was a 15-year-old male that his left mandibular third molar transplanted to the second molar sight after extraction of second molar because of unrestorable crown. During 9 month follow up transplanted tooth was asymptomatic, functional and responsive to sensibility tests. (Cold test, EPT.

  11. Maxillary First Molars with 2 Distobuccal Canals: A Case Series.

    Science.gov (United States)

    Fogel, Howard M; Cunha, Rodrigo Sanches

    2017-11-01

    An appreciation of the anatomic complexity of the root canal system is essential at every step of endodontic treatment. Endodontic treatment of teeth with unusual root canal anatomy presents a unique challenge. Eight patients underwent nonsurgical root canal treatment of 3-rooted maxillary first molars in a specialty endodontic private practice. Four cases of Weine type II and 4 cases of Weine type III canal configurations in the distobuccal root of maxillary first molars were presented.This article highlighted an uncommon anatomic variation of 2 canals in the distobuccal root of the maxillary first molar. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. An aegialodontid upper molar and the evolution of mammal dentition.

    Science.gov (United States)

    Lopatin, Alexey V; Averianov, Alexander O

    2006-08-25

    The most obvious key synapomorphy of the therian mammals is the tribosphenic pattern of their molars. Tribosphenic teeth are capable of both shearing and grinding, which substantially increase effectiveness of food processing and, in turn, permit evolution of a wide range of dietary specializations. Functional tribospheny developed repeatedly during mammalian evolution but was successful only in the Boreosphenida. The earliest stage in the development of boreosphenidan tribospheny has remained poorly understood, being documented only by lower molars of aegialodontids. Here, we report a known upper molar of an aegialodontid mammal, Kielantherium, from the Early Cretaceous of Mongolia.

  13. Prediction of postoperative pain after mandibular third molar surgery

    DEFF Research Database (Denmark)

    Rudin, Asa; Eriksson, Lars; Liedholm, Rolf

    2010-01-01

    To evaluate the predictive potential of preoperative psychological and psychophysiological variables in estimating severity of postoperative pain following mandibular third molar surgery (MTMS). Methods: Following ethical committee approval and informed consent, 40 consecutive patients scheduled...

  14. Excess molar volumes and isentropic compressibilities of binary ...

    Indian Academy of Sciences (India)

    Excess molar volume; binary liquid mixtures; isentropic compressibility; intermolecular interactions. ... mixtures are essential for fluid flow, mass flow and heat transfer processes in chemical ... Experimentally determined values of density(ρ).

  15. Evaluation of radiographic features of embedded primary molar ...

    African Journals Online (AJOL)

    2014-05-20

    May 20, 2014 ... Key words: Ankylosis, panoramic radiography, primary molar root ... coverage of the jaws is needed for diagnosis. ... and direct continuity of the bone, called as bony ankylosis. .... Floating retained root lesion mimicking.

  16. Cementoblastoma Relating to Right Mandibular Second Primary Molar

    Directory of Open Access Journals (Sweden)

    Sivakumar Nuvvula

    2016-01-01

    Full Text Available Cementoblastoma is a benign lesion of the odontogenic ectomesenchymal origin. It rarely occurs in primary dentition. This report describes a case of a cementoblastoma relating to the right mandibular second primary molar in a 7-year-old girl. Her panoramic radiograph revealed a well-defined radiopaque lesion with a radiolucent border extending from the distal surface of the mandibular right first primary molar to the distal surface of mandibular second primary molar. The tumor was attached to the mesial root of primary second molar and was excised along with the teeth involved and sent for histopathological evaluation, which showed irregular trabeculae of mineralized tissue interspersed with fibrovascular connective tissue, trabeculae of mineralized tissue with prominent reversal lines, and peripheral rimming of the mineralized tissue with blast cells. On a six-month follow-up, there has been no recurrence of the lesion.

  17. Study of Kissing Molars in Turkish Population Sample

    African Journals Online (AJOL)

    2017-06-28

    Jun 28, 2017 ... unerupted teeth; retention of the mandibular second molar is ... and November 2014 for surgical treatment retrospectively were evaluated. The cases of ... and treatment. Results: Of the 6570 radiographs included in the study,.

  18. Impacted Mandibular Third Molars: Review of Literature and a ...

    African Journals Online (AJOL)

    were screened, and 50 articles were included in the review. Causes of ... impaction rate is higher for third molars when compared with other teeth. The mandibular .... Hence, the surgical extraction of these impacted teeth has become the most ...

  19. Aspartic acid racemization in dentin of the third molar for age estimation of the Chaoshan population in South China.

    Science.gov (United States)

    Chen, Shisheng; Lv, Yanyi; Wang, Dian; Yu, Xiaojun

    2016-09-01

    Aspartic acid racemization in teeth has been increasingly used to estimate chronological age with a considerably high accuracy in forensic practice. The Chaoshan population in South China is relatively isolated in geography, and has specific lifestyle and dietary inhibits. It is still unknown whether this method is suitable for this population. The aim of this study was to analyze the relationship between chronological age and the d/l aspartic acid ratio in dentin in the third molar tooth of the Chaoshan population. Fifty-eight non-carious third molar teeth (31 mandibles and 27 maxillae), from 58 living individuals of known age (24 males and 34 females), were retrieved. Dentin was extracted from these teeth. The d- and l-aspartic acids in dentins were separated and detected by high performance liquid chromatography (HPLC). Linear regression was performed between the d/l aspartic acid ratio of dentins and chronological age. Results showed that the correlation coefficient (r) was 0.969, and the mean absolute error (MAE) was 2.19 years, its standard deviation (SD) was ±1.53 years, indicating excellent correlation. There was no significant difference in racemization rates of dentin between sexes (P=0.113, F=2.6), or between mandibles and maxillae (P=0.964, F=0.000). Results indicate that the ratio of the d and l forms of aspartic acid of dentins, in the third molar, is closely correlated with chronological age, special lifestyle do no obviously affect the accuracy of the age estimations by aspartic acid racemization of the dentin in the third molar and that aspartic acid racemization in the third molar dentin can be used as an accurate method to estimate chronological age in the Chaoshan population in South China. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Fusion or gemination? An unusual mandibular second molar

    Directory of Open Access Journals (Sweden)

    Angela Jordão Camargo

    2016-01-01

    Full Text Available Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving “second and third” molar.

  1. Managing molar-incisor hypomineralization: A systematic review.

    Science.gov (United States)

    Elhennawy, Karim; Schwendicke, Falk

    2016-12-01

    We systematically reviewed treatment modalities for MIH-affected molars and incisors. Trials on humans with ≥1 MIH molar/incisor reporting on various treatments were included. Two authors independently searched and extracted records. Sample-size-weighted annual failure rates were estimated where appropriate. The risk of bias was assessed using the Newcastle-Ottawa scale. Electronic databases (PubMed, Embase, Cochrane CENTRAL, Google Scholar) were screened, and hand searches and cross-referencing performed. Fourteen (mainly observational) studies were included. Ten trials (381 participants) investigated MIH-molars, four (139) MIH-incisors. For molars, remineralization, restorative or extraction therapies had been assessed. For restorative approaches, mean (SD) annual failure rates were highest for fissure sealants (12[6]%) and glass-ionomer restorations (12[2]%), and lowest for indirect restorations (1[3]%), preformed metal crowns (1.3 [2.1]%) and composite restorations (4[3]%). Ony study assessed extraction of molars in young patients (median age 8.2 years), the majority of them without malocclusions, but third molars in development. Spontaneous alignment of second molars was more frequent in the maxilla (55%) than the mandible (47%). For incisors, desensitizing agents successfully managed hypersensitivity. Micro-abrasion and composite veneers improved aesthetics. Few, mainly moderate to high-risk-studies investigated treatment of MIH. Remineralization or sealants seem suitable for MIH-molars with limited severity and/or hypersensitivity. For severe cases, restorations with composites or indirect restorations or preformed metal crowns seem suitable. Prior to tooth extraction as last resort factors like the presence of a general malocclusion, patients' age and the status of neighboring teeth should be considered. No recommendations can be given for MIH-incisors. Dentists need to consider the specific condition of each tooth and the needs and expectations of

  2. Bilateral maxillary fused second and third molars: a rare occurrence

    OpenAIRE

    Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

    2012-01-01

    This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the secon...

  3. Elongational viscosity of narrow molar mass distribution polystyrene

    DEFF Research Database (Denmark)

    Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...... above the linear viscoelastic prediction at intermediate strains, indicating strain hardening. The steady elongational viscosities are monotone decreasing functions of elongation rate. At elongation rates larger than the inverse reptation time, the steady elongational viscosity scales linearly...

  4. Subcutaneous emphysema during third molar surgery: a case report

    OpenAIRE

    Romeo, Umberto; Galanakis, Alexandros; Lerario, Francesco; Daniele, Gabriele Maria; Tenore, Gianluca; Palaia, Gaspare

    2011-01-01

    Extraction of third molars is the most common surgical procedure performed in oral surgery on a daily basis and, despite surgical skills and expertise, complications may occur. Complications observed during or after third molar removal may include pain, swelling, bleeding, infection, sinus perforation and nerve damage. Fortunately, with a proper management and a good surgical technique, the incidence of such events is low. Subcutaneous emphysema associated with dental extraction occurs when t...

  5. Molar exergy and flow exergy of pure chemical fuels

    International Nuclear Information System (INIS)

    Zanchini, Enzo; Terlizzese, Tiziano

    2009-01-01

    Expressions of the molar exergy and of the molar flow exergy of a pure chemical fuel are deduced rigorously from the basic principles of thermodynamics. It is shown that molar exergy and molar flow exergy coincide when the temperature T and the pressure p of the fuel are equal to the temperature T B and the pressure p B of the environment; a general relation between exergy and flow exergy is proved as a consequence. The deduction of the expression of the molar exergy of a chemical fuel for non-standard values of T B and p B is clarified. For hydrogen, carbon dioxide and several hydrocarbons, tables are reported to allow a simple calculation of the molar exergy of the fuel for any value of the temperature T B and the relative humidity φ B of the environment, in the range 268.15 K ≤ T B ≤ 313.15 K and 0.1 ≤ φ B ≤ 1, with reference to the standard atmospheric pressure. Additional tables are provided to evaluate the difference between the exergy or the flow exergy of the fuel in its given initial state and the exergy at T = T B and p = p B . In these tables, it is assumed that fuel and environment have the same temperature and that the fuel pressure varies in the range 1.01325 bar ≤ p ≤ 200 bar; the fuel may be gas or liquid.

  6. Standard molar enthalpy of formation of methoxyacetophenone isomers

    International Nuclear Information System (INIS)

    Amaral, Luísa M.P.F.; Morais, Victor M.F.; Ribeiro da Silva, Manuel A.V.

    2014-01-01

    Highlights: • Experimental and computational energetic study of methoxyacetophenone isomers. • Enthalpies of formation and phase transition determined by calorimetric techniques. • Quantum chemical calculations allowed estimation of enthalpies of formation. • Structure and energy correlations were established. - Abstract: Values of the standard (p o = 0.1 MPa) molar enthalpy of formation of 2′-, 3′- and 4′-methoxyacetophenones were derived from their standard molar energy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of sublimation/vaporization of the compounds studied. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T = 298.15 K, have been derived from the corresponding standard molar enthalpies of formation in the condensed phase and the standard molar enthalpies for the phase transition. The results obtained are −(232.0 ± 2.5), −(237.7 ± 2.7) and −(241.1 ± 2.1) kJ · mol −1 for 2′-, 3′- and 4′-methoxyacetophenone, respectively. Standard molar enthalpies of formation were also estimated from different methodologies: the Cox scheme as well as two different computational approaches using density functional theory-based B3LYP and the multilevel G3 methodologies

  7. Middle mesial canals in mandibular molars: incidence and related factors.

    Science.gov (United States)

    Nosrat, Ali; Deschenes, Raney J; Tordik, Patricia A; Hicks, M Lamar; Fouad, Ashraf F

    2015-01-01

    Although the internal anatomy of mandibular molars has been extensively studied, information about middle mesial (MM) canals is limited. The primary aim of this retrospective study was to evaluate the incidence of MM canals in mandibular first and second molars. The secondary aim was to correlate the incidence of MM canals with variables of molar type, sex, age, ethnicity, and presence of a second distal canal. All mature permanent first and second mandibular molars treated from August 2012 to May 2014 were included in the analysis. After completion of root canal instrumentation in all main canals, the clinician inspected the isthmus area of the mesial root using the dental operating microscope. If there was a catch point in this area with a file or explorer, the operator spent more time attempting to negotiate an MM canal. Seventy-five mandibular first and second molars were treated during the specified period. Fifteen (20%) teeth had negotiable MM canals. The incidence of MM canals was 32.1% in patients ≤ 20 years old, 23.8% in patients 21-40 years old, and 3.8% in patients > 40 years. Analysis of data revealed a significant difference in the distribution of MM canals among different age groups (P molar type, and presence of a second distal canal were not significant. The incidence of negotiable MM canals overall and their frequency of identification in younger patients were higher than in previous reports. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Cuartos molares supernumerarios: relato de caso clínico

    Directory of Open Access Journals (Sweden)

    Daniela Nascimento Silva

    2006-04-01

    Full Text Available Los dientes supernumerarios se diagnostican mediante exámenes radiográficos de rutina, pues generalmente son asintomáticos. Los cuartos molares representan el segundo grupo de dientes supernumerarios con más frecuencias; ocurren en posición distal a los terceros molares, especialmente en el maxilar superior, y en la mayoría de casos, estos están incluidos. El objetivo de este artículo es realizar la presentación de un caso, de una mujer de 30 anos con los cuartos molares incluidos en el maxilar inferior y describir la técnica para su remoción.Supernumerary teeth are generally asymptomatic and are diagnosed by routine X-ray tests. The fourth molar teeth represent the second group of the most frequent supernumerary teeth, occur in distal position to the third molar teeth, specially in the superior maxilla and, in most of the cases, they are included. The aim of this paper is to comment on the case of a 30-year-old woman with the fourth molar teeth included in the inferior maxilla and to describe the technique used for their removal.

  9. Effect of age, sex and level of surgical difficulty on inflammatory complications after third molar surgery.

    Science.gov (United States)

    Osunde, Otasowie D; Saheeb, Birch D

    2015-03-01

    Patients' factors such as age and sex and surgical variables such as level of difficulty have been linked with surgical outcome in third molar surgery. The aim of this study was to determine the effect of these variables on inflammatory complications in patients undergoing third molar surgery. Patients referred to our institution for surgical extraction of their impacted lower third molar between January 2007 and December 2008 were the subjects of the study. Patients' demographics as well as types of impaction, indication and level of difficulty based on Pederson criteria were obtained. Post operative pain, swelling and mouth opening limitation were evaluated at day 1, day 2, day 3, day 5 and 1 week after the surgery and analyzed. A p value of less than 0.05 was considered significant. A total of 150 patients aged 16-38 years (25.9 ± 4.47) met the inclusion criteria. Male accounted for 66 (44.0 %) while females were 84 (56.0 %), giving male to female ratio of 1:1.3. Age, sex and difficulty index had no effect on pain and trismus throughout the periods of postoperative evaluation (p > 0.05). Postoperative swelling was not affected by gender but patients above 25 years who had high scores of difficulty index had more facial swelling. The results of this study shows that age, gender and the level of surgical difficulty have no effect on pain and mouth opening limitation after third molar surgery.

  10. Magnetic resonance imaging of third molars: developing a protocol suitable for forensic age estimation.

    Science.gov (United States)

    De Tobel, Jannick; Hillewig, Elke; Bogaert, Stephanie; Deblaere, Karel; Verstraete, Koenraad

    2017-03-01

    Established dental age estimation methods in sub-adults study the development of third molar root apices on radiographs. In living individuals, however, avoiding ionising radiation is expedient. Studying dental development with magnetic resonance imaging complies with this requirement, adding the advantage of imaging in three dimensions. To elaborate the development of an MRI protocol to visualise all third molars for forensic age estimation, with particular attention to the development of the root apex. Ex vivo scans of porcine jaws and in vivo scans of 10 volunteers aged 17-25 years were performed to select adequate sequences. Studied parameters were T1 vs T2 weighting, ultrashort echo time (UTE), fat suppression, in plane resolution, slice thickness, 3D imaging, signal-to-noise ratio, and acquisition time. A bilateral four-channel flexible surface coil was used. Two observers evaluated the suitability of the images. T2-weighted images were preferred to T1-weighted images. To clearly distinguish root apices in (almost) fully developed third molars an in plane resolution of 0.33 × 0.33 mm 2 was deemed necessary. Taking acquisition time limits into account, only a T2 FSE sequence with slice thickness of 2 mm generated images with sufficient resolution and contrast. UTE, thinner slice T2 FSE and T2 3D FSE sequences could not generate the desired resolution within 6.5 minutes. Three Tesla MRI of the third molars is a feasible technique for forensic age estimation, in which a T2 FSE sequence can provide the desired in plane resolution within a clinically acceptable acquisition time.

  11. Primary molar pulpotomy: a systematic review and network meta-analysis.

    Science.gov (United States)

    Lin, Po-Yen; Chen, Hsueh-Szu; Wang, Yu-Hsiang; Tu, Yu-Kang

    2014-09-01

    Pulpotomy is a common procedure to treat asymptomatic reversible pulpitis in primary molars. The aim of this study is to undertake a systematic review and a network meta-analysis to compare the clinical and radiographic outcomes of different pulpotomy procedures in primary molars. Three authors performed data extraction independently and in duplicate using data collection forms. Disagreements were resolved by discussion. An electronic literature search was performed within MEDLINE (via PubMed), ScienceDirect, Web of Science, Cochrane, and ClinicalKey databases until December 2012. Medications for pulpotomy including formocresol, ferric sulfate, calcium hydroxide, and mineral trioxide aggregate (MTA), and laser pulpotomy are compared using Bayesian network meta-analyses. The outcome is the odds ratio for clinical and radiographic failure including premature tooth loss at 12 and 24 months after treatments amongst different treatment procedures. 37 studies were included in the systematic review, and 22 of them in the final network meta-analyses. After 18-24 months, in terms of treatment failure, the odds ratio for calcium hydroxide vs. formocresol was 1.94 [95% credible interval (CI): 1.11, 3.25]; 3.38 (95% CI: 1.37, 8.61) for lasers vs. formocresol; 2.16 (95% CI: 1.12, 4.31) for calcium hydroxide vs. ferric sulfate; 3.73 (95% CI: 1.27, 11.67) for lasers vs. ferric sulfate; 0.47 (95% CI: 0.26, 0.83) for MTA vs. calcium hydroxide; 3.76 (95% CI: 1.39, 10.08) for lasers vs. After 18-24 months, formocresol, ferric sulfate, and MTA showed significantly better clinical and radiographic outcomes than calcium hydroxide and laser therapies in primary molar pulpotomies. The network meta-analyses showed that MTA is the first choice for primary molar pulpotomies. However, if treatment cost is an issue, especially when the treated primary molars are going to be replaced by permanent teeth, ferric sulfate may be the choice. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Prevalence of missing and impacted third molars in adults aged 25 years and above

    Science.gov (United States)

    Jung, Yun-Hoa

    2013-01-01

    Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health. PMID:24380060

  13. Prevalence of missing and impacted third molars in adults aged 25 years and above

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yansan (Korea, Republic of)

    2013-12-15

    The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

  14. Prevalence of missing and impacted third molars in adults aged 25 years and above

    International Nuclear Information System (INIS)

    Jung, Yun Hoa; Cho, Bong Hae

    2013-01-01

    The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

  15. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Blanco, Elena; Ruso, Juan M.; Prieto, Gerardo; Sarmiento, Felix

    2005-01-01

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature

  16. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2005-12-15

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.

  17. Aetiology of molar-incisor hypomineralisation (MIH) in Brazilian children.

    Science.gov (United States)

    Souza, J F; Jeremias, F; Costa-Silva, C M; Santos-Pinto, L; Zuanon, A C C; Cordeiro, R C L

    2013-06-25

    To determine the potential aetiological factors related to molar-incisor hypomineralisation (MIH) in Brazilian children. A total of 1,151 children aged 7-12 years (mean 8.86 ± 1.28), born and living in the urban area of Araraquara, Brazil, were examined by two examiners evaluating the presence of MIH according to criteria suggested by the European Academy of Paediatric Dentistry (2003). Their mothers completed a structured questionnaire about medical history, from pregnancy to the first 3 years of the children's life. Descriptive analyses of data and odds ratios (OR) with 95 % test-based confidence intervals (CI) were estimated. Chi-square test was used to evaluate the differences between groups. The prevalence of MIH in the children was 12.3 %. The interviewing response rate was 90.4 %. The prevalence of miscarriage history (25 vs. 15.4 %; OR = 1.21; 95 % CI 0.30-4.92) and occurrence of anaemia (23 vs. 12.4 %; OR = 2.07; 95 % CI 0.50-8.63) were higher in mothers from MIH group than those from non-MIH group. However, these associations were not statically significant. In the children's medical history, rhinitis, bronchitis (56.5 vs. 52.5 %; OR = 1.17; 95 % CI 0.82-1.68), and high fever (20.4 vs. 18.2 %; OR = 1.14; 0.73-1.76) were more prevalent in MIH group, but there were no significant differences between the groups (p > 0.05). No possible aetiological factor investigated was associated with MIH. Prospective studies are needed to define the aetiological factors involved with MIH.

  18. Orthodontic Replacement of Lost Permanent Molar with Neighbor Molar: A Six-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Taisa Boamorte Raveli

    2017-01-01

    Full Text Available Extraction is very frequent indication in orthodontic planning, especially when there are crowding, biprotrusion, and aesthetically unpleasant profiles. Next to extraction comes space closure, which represents a challenge for orthodontists because of extended treatment time, discomfort created for the patient, tissue tolerance, and stability concerns. When it comes to what mechanics to choose for space closure, loops present two major advantages in relation to sliding mechanics: absence of abrasion and possibility to reach pure dental translation. A case is presented where an adult female patient with early loss of the first lower permanent molars, minor lower crowding, and tooth biprotrusion was treated with upper first bicuspids extraction along with upper and lower space closure done with T-loops to promote best space closure control in order to correct the malocclusion and enhance facial aesthetics.

  19. Orthodontic Replacement of Lost Permanent Molar with Neighbor Molar: A Six-Year Follow-Up

    Science.gov (United States)

    Shintcovsk, Ricardo Lima; Knop, Luegya Amorim Henriques; Sampaio, Luana Paz

    2017-01-01

    Extraction is very frequent indication in orthodontic planning, especially when there are crowding, biprotrusion, and aesthetically unpleasant profiles. Next to extraction comes space closure, which represents a challenge for orthodontists because of extended treatment time, discomfort created for the patient, tissue tolerance, and stability concerns. When it comes to what mechanics to choose for space closure, loops present two major advantages in relation to sliding mechanics: absence of abrasion and possibility to reach pure dental translation. A case is presented where an adult female patient with early loss of the first lower permanent molars, minor lower crowding, and tooth biprotrusion was treated with upper first bicuspids extraction along with upper and lower space closure done with T-loops to promote best space closure control in order to correct the malocclusion and enhance facial aesthetics. PMID:29318054

  20. Standardised studies on Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM): a need.

    Science.gov (United States)

    Elfrink, M E C; Ghanim, A; Manton, D J; Weerheijm, K L

    2015-06-01

    In November 2014, a review of literature concerning prevalence data of Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) was performed. A search of PubMed online databases was conducted for relevant articles published until November 2014. The reference lists of all retrieved articles were hand-searched. Studies were included after assessing the eligibility of the full-text article. Out of 1078 manuscripts, a total of 157 English written publications were selected based on title and abstract. Of these 157, 60 were included in the study and allocated as 52 MIH and 5 HSPM, and 3 for both MIH and HSPM. These studies utilised the European Academy of Paediatric Dentistry judgment criteria, the modified index of developmental defects of enamel (mDDE) and self-devised criteria, and demonstrated a wide variation in the reported prevalence (MIH 2.9-44 %; HSPM 0-21.8 %). Most values mentioned were representative for specific areas. More studies were performed in cities compared with rural areas. A great variation was found in calibration methods, number of participants, number of examiners and research protocols between the studies. The majority of the prevalence studies also investigated possible aetiological factors. To compare MIH and HSPM prevalence and or aetiological data around the world, standardisation of such studies seems essential. Standardisation of the research protocol should include a clearly described sample of children (minimum number of 300 for prevalence and 1000 for aetiology studies) and use of the same calibration sets and methods whereas aetiological studies need to be prospective in nature. A standardised protocol for future MIH and HSPM prevalence and aetiology studies is recommended.

  1. Endodontic treatment of an unusual connation of permanent mandibular molars: a case report.

    Science.gov (United States)

    Liu, Shengbo; Fan, Bing; Peng, Bin; Fan, Mingwen; Bian, Zhuan

    2006-10-01

    A 27-year-old patient with an anomalous mandibular molar was referred for endodontic therapy. Clinical and radiographic examination revealed the connation of a second mandibular molar with a third molar. Challenging endodontic therapy was performed in the unusual connated molars. A 2-year recall showed good treatment result.

  2. Pattern of third molar impaction in a Saudi population

    Directory of Open Access Journals (Sweden)

    Ali H Hassan

    2010-10-01

    Full Text Available Ali H Hassan11Department of Preventive Dental Sciences, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi ArabiaObjective: To evaluate the current pattern of third molar impaction in a sample of Saudi patients.Methods: One thousand thirty-nine orthopantomograms (OPG of patients ranging in age from 19 to 46 years (536 males and 503 females were evaluated to determine the frequency of impacted third molars, their levels of eruption, and their angulations.Results: Four hundred twenty-two (40.5% of the 1039 OPG showed at least one impacted third molar, with no significant difference between males (222; 52.6% and females (200; 47.4% (P = 0.284. The most common number of impacted third molars per OPG was one (72.5%. Impacted third molars were 1.64 times more likely to occur in the mandible than in the maxilla. The most common angulation of impaction in the mandible was the mesial (33.4%, while the most common angulation in the maxilla, was the vertical (49.6%. Level B impaction was the most common in both maxilla (48.2% and mandible (67.7%. There was no significant difference in the frequency of impaction between the right and left sides in both jaws.Conclusion: The pattern of third molar impaction in the western region of Saudi Arabia is characterized by a high prevalence of impaction that is greater in the mandibles and with no sex predilection.Keywords: third molar, impaction, prevalence, Saudi 

  3. Genetic integration of molar cusp size variation in baboons.

    Science.gov (United States)

    Koh, Christina; Bates, Elizabeth; Broughton, Elizabeth; Do, Nicholas T; Fletcher, Zachary; Mahaney, Michael C; Hlusko, Leslea J

    2010-06-01

    Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone-metacone and protocone-hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the nonoccluding cusps consistently yield high genetic correlations, especially the metaconid-paracone and metaconid-metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar. Copyright 2009 Wiley-Liss, Inc.

  4. Odor concentration invariance by chemical ratio coding

    Directory of Open Access Journals (Sweden)

    Naoshige Uchida

    2008-08-01

    Full Text Available Many animal species rely on chemical signals to extract ecologically important information from the environment. Yet in natural conditions chemical signals will frequently undergo concentration changes that produce differences in both level and pattern of activation of olfactory receptor neurons. Thus, a central problem in olfactory processing is how the system is able to recognize the same stimulus across different concentrations. To signal species identity for mate recognition, some insects use the ratio of two components in a binary chemical mixture to produce a code that is invariant to dilution. Here, using psychophysical methods, we show that rats also classify binary odor mixtures according to the molar ratios of their components, spontaneously generalizing over at least a tenfold concentration range. These results indicate that extracting chemical ratio information is not restricted to pheromone signaling and suggest a general solution for concentration-invariant odor recognition by the mammalian olfactory system.

  5. Orthodontic space closure after first molar extraction without skeletal anchorage.

    Science.gov (United States)

    Jacobs, Collin; Jacobs-Müller, Claudia; Luley, Carolin; Erbe, Christina; Wehrbein, Heiner

    2011-03-01

    The aim of the study was an analysis of effects and side-effects during mesialization of second molars after extraction of the first permanent molars using the anterior dentition/premolars (PM) as an anchorage unit. A total of 35 patients were examined retrospectively who had undergone unilateral or bilateral first permanent molar extraction in the upper or lower arch due to carious lesions. Space closure was carried out in all cases through mesialization of the second molar using an elastic chain fixed to an edgewise stainless steel archwire and tying the anterior dentition/PM together with a continuous laceback ligature. Tooth movement was assessed from lateral cephalograms, orthopantomograms (OPGs) and images of the patient's study casts taken before and after the end of therapy. Space closure after first molar extractions by mesialization of the second molars without skeletal anchorage was largely achieved by bodily forward movement of the teeth, including a small tipping component or tooth-uprighting component when molars were already mesially inclined. Unilateral and bilateral mesialization of the second molars led to retrusion in the maxilla and mandible [(∆incl.=-3.6° (max., bil.), ∆incl.=-4.2° (mand., bil.)] and to translational retraction [(∆s=-2.3 mm (max., bil.), ∆s=-1.6 mm (mand., bil.)] of the incisors. Examination of the soft tissues revealed an increased posterior displacement of the upper and lower lips to the esthetic line [(∆s=-2.8 mm (max. bil.), ∆s=-2.2 mm (mand., bil.)]. In cases of unilateral mesialization less than 50% of the patients had a slight midline deviation in the mandible towards the extraction side. Side effects during mesialization of the second molars without skeletal anchorage in the anterior dentition/PM were observed primarily affecting the incisors integrated into the anterior anchorage unit. These side-effects resulted in posterior displacement of the soft tissues, including a change in profile. This must be

  6. Histopathologic Evaluation of Follicular Tissues Associated with Impacted Third Molars

    Directory of Open Access Journals (Sweden)

    M. Khorasani

    2008-06-01

    Full Text Available Objective: The aim of the present study was to histopathologically evaluate follicular tissues of third molars with pericoronal radiolucenciesof less than 2 millimeters.Materials and Methods: In this descriptive analytic study, 100 impacted third molars with normal follicular spaces were removed and their pericoronaltissues submitted for histopathologic examination. Different characteristicsof the epithelium and connective tissue were evaluated in all cases. Statisti-cal analysis was performed using chi square and Mann-Whitney tests.Results: In our study sample, 74% of the patients were female and 26% were male, ranging in age from 13 to 54 years (mean, 25.3 years. Lining epithelium was observed in 69% of the specimens of which 31%, 23% and 14% was cuboidal, squamous and columnar, respectively. A significant re-lationship was found between the presence of squamous epithelium and pa-tient age (P<0.05. Nonspecific chronic inflammation was the only patho-logic finding observed in 44% of the specimens. Inflammation was signifi-cantly associated with age and squamous metaplasia (P<0.05.Conclusion: Considering that pathologic lesions were not observed in anyof the studied cases, unerupted third molars should not be removed unless there is a clinical indication to do so, or in case the impacted molar shows evidence of pathological changes. Follow-up is suggested for asympto-matic impacted third molars.

  7. Elective extractions of first permanent molars: a review

    Directory of Open Access Journals (Sweden)

    Melike Kiraz

    2018-05-01

    Full Text Available Permanent first molar teeth possess a key role in the setting-up of the occlusion, contribute significantly to the chewing function and serve as a guide for other teeth. However, it is frequently encountered that permanent first molar teeth are extracted due to the predicted negative prognoses of caries or developmental defects. As a result of the uncontrolled extraction of the permanent first molar teeth during the growth and development period, drifting of adjacent teeth, continued eruption of the opposing teeth and displacements can be seen. Furthermore, following one-sided extraction, midline deviations, oppositional tooth eruption, skeletal and dental asymmetry, unilateral chewing habits, and temporo-mandibular joint disorders may occur. To prevent these pathological conditions and to maintain the stability of the occlusal relation, it is necessary to do compensation and balancing extractions of the permanent first molar teeth on the opposite/symmetric arc, assuming mesial drag of the permanent second and third molar teeth. With such controlled-extractions, especially in Class I cases, orthodontic or prosthetic treatments, which may require extra time, cost and effort, could be prevented and a conceivable occlusion can be established.

  8. Requirement of alveolar bone formation for eruption of rat molars

    Science.gov (United States)

    Wise, Gary E.; He, Hongzhi; Gutierrez, Dina L.; Ring, Sherry; Yao, Shaomian

    2011-01-01

    Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (BMP6), was inhibited by injection of the 1st mandibular molar of the rat with an siRNA targeted against BMP6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption either was delayed or completely inhibited (7 molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced as compared to the erupted first molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that BMP6 may be an essential gene for promoting this growth. PMID:21896048

  9. Lingual nerve injury following surgical removal of mandibular third molar

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    Abduljaleel Azad Samad

    2017-12-01

    Full Text Available Background and objective: The close proximity of lingual nerve in relation to the lingual cortical bone of the posterior mandibular third molar is clinically important because lingual nerve may be subjected to trauma during surgical removal of the impacted lower third molar. This prospective study aimed to evaluate the incidence of lingual nerve paresthesia following surgical removal of mandibular third molar in College of Dentistry, Hawler Medical University. Methods: A total of 116 third molars surgery were carried out under local anesthesia for 116 patients for removal of lower mandibular teeth Using Terence Ward's incision made in all cases, and after that, the buccal flap was reflected, lingual tissues had been retracted during bone removal with a periosteal elevator. The sensory disturbance was evaluated on the 7th postoperative day by standard questioning the patients: “Do you have any unusual feeling in your tongue, lingual gingiva and mucosa of the floor of the mouth?" Results: One patient experienced sensory disturbance, the lingual nerve paresthesia incidence was 0.9% as a transient sensory disturbance, while no patient of permanent sensory disturbance. Conclusion: The incidence of injury to the lingual nerve can be minimized by careful clinical evaluation, surgeon’s experience, surgical approach and knowledge about anatomical landmarks during surgical removal of an impacted lower third molar tooth.

  10. Western Saudi adolescent age estimation utilising third molar development.

    Science.gov (United States)

    Alshihri, Amin M; Kruger, Estie; Tennant, Marc

    2014-07-01

    The aim of this study was to establish reference data on third molar morphology/development for age estimation in Western Saudi adolescents, between ages 14 and 23 years of old. The orthopantomograms of 130 individuals (males and females), were examined, and the stage of third molar development were evaluated. Mean ages, standard deviations, and percentile distributions are presented for each stage of development. The mean estimated age for all participants (n = 130) was 219.7 months, and this differed significantly (P age (226.5 months). Deviations of predicted age from real age showed 28.5% of all participants had their age estimated within 1 year (±12 months) of their chronological age. Most (43%) had their age underestimated by more than 12 months and the remaining 28.5% had their age overestimated by more than 12 months of their chronological age. Differences in left-right symmetry information of third molars were detected and were higher in the maxilla (92%) than in the mandible (82%). For all molars reaching stage "H" most individuals (males and females) were over the age 18 years of old. Males reach the developmental stages earlier than females. Third molar tooth development can be reliably used to generate mean age and the estimated age range for an individual of unknown chronological age. Further studies with large populations are needed for better statistical results.

  11. Age of patient at the extraction of the third molar.

    Science.gov (United States)

    Kautto, A; Vehkalahti, M M; Ventä, I

    2018-04-13

    The purpose of this study was to assess the age of patients at the time of extraction of third molars. Our data included all routine and surgical extractions of third molars (n=8199 teeth) performed by general and specialist dentists of the public oral health services of the city of Helsinki over the period 2013-2014. Measurements included patient's age, gender, the identified third molar, the type of anaesthesia, the method of extraction, and the diagnosis at extraction. Patients' ages ranged from 10 to 99years. We found significant differences between younger and older age groups: third molar extractions occurred more often for women than for men below the age of 30years (Page of 40years, but the corresponding prevalences reversed after the age of 40years. Diagnoses at extraction differed between younger and older patients. We conclude that the treatment pattern of third molars at public health services varies greatly over a lifetime, and that a greater variety exists than had been reported previously from oral and maxillofacial units. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Autologous Platelet-rich Plasma after Third Molar Surgery.

    Science.gov (United States)

    Gandevivala, Adil; Sangle, Amit; Shah, Dinesh; Tejnani, Avneesh; Sayyed, Aatif; Khutwad, Gaurav; Patel, Arpit Arunbhai

    2017-01-01

    The aim of this study is to compare the efficacy of autologous platelet-rich plasma (PRP) in the third molar impactions, with respect to: pain, swelling, healing, and periodontal status distal to the second molar in patients who need surgical removal of bilateral impacted mandibular third molars. Twenty-five patients of both sexes aged between 16 and 60 years who required bilateral surgical removal of their impacted third molars and met the inclusion criteria were included in the study. After surgical extraction of the third molar, primary closure was performed in the control group, whereas PRP was placed in the socket followed by primary closure in the case group. The outcome variables were pain, swelling, wound healing, and periodontal probe depth that were follow-up period of 2 months. Quantitative data are presented as mean. Statistical significance was checked by t -test. There was a difference in the pain (0.071) and facial swelling (0.184), reduction between test and control on day 3, but it was not found to be significant. Periodontal pocket depth (0.001) and wound healing (0.001) less in case group compared with the control group was found to be significant. The use of PRP lessens the severity of immediate postoperative sequelae and decreases preoperative pocket depth.

  13. Evaluation of skeletal and dental age using third molar calcification, condylar height and length of the mandibular body.

    Science.gov (United States)

    Kedarisetty, Sunil Gupta; Rao, Guttikonda Venkateswara; Rayapudi, Naveen; Korlepara, Rajani

    2015-01-01

    To identify the most reliable method for age estimation among three variables, that is, condylar height, length of mandibular body and third molar calcification by Demirjian's method. Orthopantomograms and lateral cephalograms of 60 patients with equal gender ratio were included in the study, among each gender 15 subjects were below 18 years and 15 subjects were above 18 years. Lateral cephalograms were traced, height of condyle and mandibular body are measured manually on the tracing paper, OPG's were observed on radiographic illuminator and maturity score of third molar calcification was noted according to Demirjian's method. All the measurements were subjected to statistical analysis. The results obtained are of no significant difference between estimated age and actual age with all three parameters (P > 0.9780 condylar height, P > 0.9515 length of mandibular body, P > 0.8611 third molar calcification). Among these three, length of mandibular body shows least standard error test (i.e. 0.188). Although all three parameters can be used for age estimation, length of mandibular body is more reliable followed by height of condyle and third molar calcification.

  14. Standard molar enthalpies of formation of monochloroacetophenone isomers

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.

    2010-01-01

    The standard (p 0 =0.1MPa) molar enthalpies of formation of the liquids 2'-, 3'-, and 4'-chloroacetophenones were derived from the standard molar energies of combustion, in oxygen, to yield CO 2 (g) and HCl . 600H 2 O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet microcalorimetry was used to measure the enthalpies of vaporization of the three compounds. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the chloroacetophenone isomers, in the gaseous phase, at T = 298.15 K. (table) An empirical scheme, developed by Cox, was used to estimate the gas-phase enthalpies of formation and the obtained values were compared with the experimental ones.

  15. COMPLICATIONS AFTER EXTRACTION OF IMPACTED THIRD MOLARS - LITERATURE REVIEW

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    Elitsa G. Deliverska

    2016-07-01

    Full Text Available Third molar surgery is the most common procedure performed by oral and maxillofacial surgeons worldwide. This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Complications, such as pain, dry socket, swelling, paresthesia of the lingual or inferior alveolar nerve, bleeding, and infection are most common. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical history, oral contraceptives, presence of pericoronitis, poor oral hygiene, smoking, type of impaction, relationship of third molar to the inferior alveolar nerve, surgical time, surgical technique, surgeon experience, use of perioperative antibiotics, use of topical antiseptics, use of intra-socket medications, and anaesthetic technique. For the general dental practitioner, as well as the oral and maxillofacial surgeon, it is important to be familiar with all the possible complications after this procedure. This improves patient education and leads to prevention, early recognition and management.

  16. Standard molar enthalpies of formation of monochloroacetophenone isomers

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Amaral, Luisa M.P.F. [Centro de Investigacao em Quimica, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2010-12-15

    The standard (p{sup 0}=0.1MPa) molar enthalpies of formation of the liquids 2'-, 3'-, and 4'-chloroacetophenones were derived from the standard molar energies of combustion, in oxygen, to yield CO{sub 2}(g) and HCl . 600H{sub 2}O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet microcalorimetry was used to measure the enthalpies of vaporization of the three compounds. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the chloroacetophenone isomers, in the gaseous phase, at T = 298.15 K. (table) An empirical scheme, developed by Cox, was used to estimate the gas-phase enthalpies of formation and the obtained values were compared with the experimental ones.

  17. Pendulum Therapy of Molar Distalization in Mixed Dentition.

    Science.gov (United States)

    Patil, Raju Umaji; Prakash, Amit; Agarwal, Anshu

    2016-01-01

    Early and timely pedo-orthodontic treatment is aimed at eliminating the disturbances of skeletal or dentoalveolar development, to harmonize the stomatognathic system before the full eruption of all permanent teeth. The advantages of pendulum appliance are its minimal dependence on patient's compliance (child cooperation), ease of fabrication, onetime activation and adjustment of the springs if necessary to correct minor transverse and vertical molar positions. This article reports a successful treatment method of class II malocclusion with pendulum appliance in mixed dentition phase. Distalization of maxillary molar was done, followed by guidance of canine impaction orthodontically and other dental correction using 0.022 MBT appliances. Posttreatment results were stable and remarkable. How to cite this article: Patil RU, Prakash A, Agarwal A. Pendulum Therapy of Molar Distalization in Mixed Dentition. Int J Clin Pediatr Dent 2016;9(1):67-73.

  18. La hiperdontia en región de molares Hyperdontia in molar region

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    George Táccio de Miranda Candeiro

    2011-12-01

    Full Text Available La hiperdontia constituye una de las anomalías más estudiadas de la dentición humana. Esa alteración representa la aparición de uno o más dientes en cantidades mayores de lo normal, que puede ocurrir en la mandíbula o maxila y de manera unilateral o bilateral. La etiología de los dientes supernumerarios puede ser explicada principalmente por hiperactividad de la lámina dentaria en la fase inicial. Es importante la detección precoz de dientes supernumerarios porque se ha visto una serie de complicaciones como los diastemas, que pueden causar en la cavidad bucal: retardo de la erupción o dientes impactados, posicionamiento inadecuado de dientes permanentes, desajuste oclusal y el desarrollo de quistes y tumores odontógenos. Así el diagnóstico es normalmente realizado a partir de un examen radiográfico convencional, principalmente la radiografía panorámica. Este trabajo tuvo como objetivo relatar 4 casos clínicos de pacientes con presencia de molares supernumerarios, que fueron atendidos en el Servicio de Radiología de la Escuela de Odontología de la Universidad Federal de Ceará.Hyperdontia is one of the more studied anomalies of human dentition. This alteration represents the appearance of one or more teeth in a number greater of normal, occurring in mandible or in maxilla and could be unilateral or bilateral. The etiology of supernumerary teeth may be explained mainly due to the hyperactivity of dental plate in its initial phase; its early detection is important because of there have been a series of complications that may to cause diastemata, eruption retard or impacted teeth, inappropriate positioning of permanent teeth, occlusal misalignment and the development of odontogenic cysts or tumors. Thus, the diagnosis is normally made from a conventional radiographic examination, mainly the panoramic X-ray. The objective of present paper is the present four clinical cases of patients presenting with supernumerary molars, seen in

  19. Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction

    Science.gov (United States)

    Jiang, Qian; Qiu, Yating; Yang, Chi; Yang, Jingyun; Chen, Minjie; Zhang, Zhiyuan

    2015-01-01

    Abstract Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction. The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus. We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar. The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials. We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise. A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75–5.52, P piezosurgery groups. The number of included randomized controlled trials and the sample size of each trial were relatively small, double blinding was not possible, and cost analysis was unavailable due to a lack of data. Our meta-analysis indicates that although patients

  20. Fibrous epulis associated with impacted lower right third molar

    Directory of Open Access Journals (Sweden)

    Ni Putu Mira Sumarta

    2009-12-01

    Full Text Available Background: Epulis or epulides are lesions associated with gingival tissues. Fibrous epulis is a type of hyperplastic fibrous tissue mass located at the gingival which is slow growing, painless, having same color as the oral mucosa and firm on palpation. Anterior regions of the oral cavity are the frequently affected sites as these areas are more prone to be affected by calculus deposition and poor plaque control due to frequent teeth malposition. Removal of any irritating factors and excision of the lesion are the usual treatments. Purpose: This case report presents a rare case of fibrous epulis which occurred in the posterior region of the oral cavity and associated with impacted lower third molar. Case: A case of fibrous epulis at the lower right third molar area of three months duration is presented. The mass was slow growing, painless and on examination it was a pedunculated mass overlying the unerupted lower right third molar, having same color with the oral mucosa and firm on palpation. Clinically, the lesion was diagnosed as fibrous epulis associated with impacted lower right third molar. Case management: The treatment were surgical excision of the epulis and removal of the lower right third molar. The histopathology result showed tissue with squamous epithelial lining, achanthotic fibrous connective tissue, mononuclear inflammatory cells and few capillaries without signs of malignancy. This is consistent with the diagnosis of fibrous epulis. Conclusion: Fibrous epulis, although frequently occurred at the anterior region of the oral cavity, may rarely grow at the area of lower third molar. This phenomenon supports the theory that epulis can grow on any surface of oral mucous membrane as long as local irritants are present.

  1. Partial Molar Volumes of Aqua Ions from First Principles.

    Science.gov (United States)

    Wiktor, Julia; Bruneval, Fabien; Pasquarello, Alfredo

    2017-08-08

    Partial molar volumes of ions in water solution are calculated through pressures obtained from ab initio molecular dynamics simulations. The correct definition of pressure in charged systems subject to periodic boundary conditions requires access to the variation of the electrostatic potential upon a change of volume. We develop a scheme for calculating such a variation in liquid systems by setting up an interface between regions of different density. This also allows us to determine the absolute deformation potentials for the band edges of liquid water. With the properly defined pressures, we obtain partial molar volumes of a series of aqua ions in very good agreement with experimental values.

  2. Treatment of Ectopic Mandibular Second Permanent Molar with Elastic Separators

    Directory of Open Access Journals (Sweden)

    R. Rajesh

    2014-01-01

    Full Text Available Ectopic eruption is a developmental disturbance in which the tooth fails to follow its normal eruption pathway. Ectopic eruption of the second molar is relatively rare. This paper presents the case of thirteen-year-old male with an ectopic mandibular second permanent molar. The condition was corrected with surgical exposure and placement of elastic separators. This case report lays emphasis on the practice of basic methods to obtain acceptable results rather than extensive surgical or orthodontic corrections. It is advised that ectopic teeth should not be neglected especially when it concerns developing caries and malocclusion.

  3. Clinical and orthopantomographic evaluation of mandibular third molar

    Directory of Open Access Journals (Sweden)

    F K Saraswati

    2010-01-01

    Full Text Available Objective: To evaluate sensitivity of orthopentograph (OPG in assessing the number and morphology of roots of the mandibular third molar. Materials and Methods : The study population consisted of 100 ILTMs (impacted lower third molars ranging from 18 to 42 years with equal sex distribution. All the teeth were subsequently extracted , collected and compared with OPG features for position, numb,er, morphology, and relation to mandibular canal. Conclusion: In conclusion, a large sample study is suggested with techniques like Clark′s and right angle technique which determines the three-dimensional orientation of the impacted teeth.

  4. Endodontic Management of a Maxillary Molar with Three Mesiobuccal Canals

    Directory of Open Access Journals (Sweden)

    Sirisha Gundam

    2014-01-01

    Full Text Available It is imperative that the clinician should have comprehensive knowledge about the normal anatomy and its variations of the teeth as the deviations from the usual are very common. An increased awareness of unusual anatomy and a better understanding of the root canal system guide the clinician in accurate diagnosis and treatment of such variations in order to achieve a successful endodontic outcome. The maxillary first molar has been shown to have a wide variation in respect to the number of canals specifically noted in the mesiobuccal root. The current case report shows the successful management of a maxillary molar in which the mesiobuccal root had three canals.

  5. Double versus single cartridge of 4% articaine infiltration into the retro-molar area for lower third molar surgery.

    Science.gov (United States)

    Sawang, Kamonpun; Chaiyasamut, Teeranut; Kiattavornchareon, Sirichai; Pairuchvej, Verasak; Bhattarai, Bishwa Prakash; Wongsirichat, Natthamet

    2017-06-01

    There are no studies regarding 4% articaine infiltration injection into the retro-molar area for an impacted lower third molar (LITM) surgery. This study aimed to evaluate the efficacy of infiltration using 1.7 ml (single cartridge: SC) of 4% articaine versus 3.4 ml (double cartridges: DC) of 4% articaine with 1:100,000 epinephrine in LITM surgery. This study involved 30 healthy patients with symmetrical LITM. The patients were assigned to receive either a DC or SC of 4% articaine with 1:100,000 epinephrine as a local anesthetic for each operation. Onset, duration, profoundness, need for additional anesthetic administration, total volume of anesthetic used, vitality of the tooth, and pain score during operation were recorded. The DC of 4 % articaine had a significantly higher success rate (83.3%) than did the SC (53.3%; P molar region can be an alternative anesthetic for LITM surgery.

  6. Apparent molar volumes, isobaric expansion coefficients, and isentropic compressibilities, and their H/D isotope effects for some aqueous carbohydrate solutions

    International Nuclear Information System (INIS)

    Bernal, P.J.; Van Hook, W.A.

    1986-01-01

    The molar volumes, isobaric expansion coefficients, and isentropic compressibilities of solutions of a number of carbohydrates and their deuterated isomers were determined in H 2 O and D 2 O between 288.15 and 328.15 K and over a wide range of solute-to-solvent mole ratios. The results are discussed in terms of the specific hydration model. (author)

  7. Relationship between the partial molar and molar quantity of a thermodynamic state function in a multicomponent mixture – revisited

    International Nuclear Information System (INIS)

    Näfe, H.

    2013-01-01

    As far as a multicomponent mixture is concerned, different versions exist in the literature for the relationship between the partial molar and molar quantity of a thermodynamic state function with the most prominent example of the two quantities being the activity coefficient of an arbitrary component and the excess Gibbs free energy of a mixture comprising this component. Since the relationships published so far have to a large degree been derived independently of each other and result from apparently conflicting approaches, they are still considered as separate subjects in the literature. It is demonstrated that despite this curious situation all relationships are equivalent to each other from a mathematical point of view

  8. SIGNS Molar tooth sign − looking beyond the obvious

    African Journals Online (AJOL)

    tooth are represented by thick, perpendicular, non-decussated superior cerebellar peduncles, while the 'body' of the molar tooth is formed by the cerebral peduncles of the brainstem with a deep interpeduncular fossa (Fig. 1a).[3]. Diffusion tensor tractography confirms the failure of superior cerebellar peduncle decussation.

  9. Antibiotic prophylaxis in third molar surgery: a review

    NARCIS (Netherlands)

    Oomens, Marjolijn A. E.; Forouzanfar, Tymour

    2012-01-01

    Objective. Controversy exists about the efficacy of antibiotic prophylaxis in preventing complications after lower third molar surgery. For evidence-based recommendation, a review was performed on clinical trials reporting the use of antibiotic prophylaxis compared with no treatment or placebo with

  10. Antibiotic prophylaxis in third molar surgery: a review

    NARCIS (Netherlands)

    Oomens, M.A.E.; Forouzanfar, T.

    2012-01-01

    Objective Controversy exists about the efficacy of antibiotic prophylaxis in preventing complications after lower third molar surgery. For evidence-based recommendation, a review was performed on clinical trials reporting the use of antibiotic prophylaxis compared with no treatment or placebo with

  11. Molar extinction coefficients of solutions of some organic compounds

    Indian Academy of Sciences (India)

    efficients of these compounds have been used to calculate effective atomic numbers and electron densities. The additivity ... Molar extinction coefficients; effective atomic numbers; electron density. PACS Nos 29.30. ... the radiation path and is linearly dependent on the concentration of the absorbing species. This is most ...

  12. Partial Molar Volume of Methanol in Water: Effect of Polarizability

    Czech Academy of Sciences Publication Activity Database

    Moučka, F.; Nezbeda, Ivo

    2009-01-01

    Roč. 74, č. 4 (2009), s. 559-563 ISSN 0010-0765 R&D Projects: GA AV ČR IAA400720802 Institutional research plan: CEZ:AV0Z40720504 Keywords : water–methanol mixtures * partial molar volume * polarizability Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.856, year: 2009

  13. Standard molar enthalpies of formation of 1- and 2-cyanonaphthalene

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.; Barros, Ana L.M.; Bessa, Ana R.C.; Brito, Barbara C.S.A.; Vieira, Joana A.S.; Martins, Silvia A.P.

    2011-01-01

    Highlights: → Enthalpies of formation of 1- and 2-cyanonaphthalene were measured by combustion calorimetry. → Vapor pressures of crystalline 1- and 2-cyanonaphthalene obtained by Knudsen effusion mass loss technique. → Enthalpies, entropies and Gibbs functions of sublimation at T = 298.15 K were calculated. - Abstract: The standard (p o = 0.1 MPa) molar enthalpies of formation, in the crystalline state, of the 1- and 2-cyanonaphthalene were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static-bomb combustion calorimetry. Vapor pressure measurements at different temperatures, using the Knudsen mass loss effusion technique, enabled the determination of the enthalpy, entropy, and Gibbs energy of sublimation, at T = 298.15 K, for both isomers. The standard molar enthalpies of sublimation, at T = 298.15 K, for 1- and 2-cyanonaphthalene, were also measured by high-temperature Calvet microcalorimetry. (table) Combining these two experimental values, the gas-phase standard molar enthalpies, at T = 298.15 K, were derived and compared with those estimated by employing two different methodologies: one based on the Cox scheme and the other one based on G3MP2B3 calculations. The calculated values show a good agreement with the experimental values obtained in this work.

  14. Experimental standard molar enthalpies of formation of some methylbenzenediol isomers

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.

    2009-01-01

    The present work is part of a research program on the energetics of formation of alkyl substituted benzenediols, aiming the study of the enthalpic effect of the introduction of methyl substituents into benzenediols. In this work we present the results of the thermochemical research on 2-methylresorcinol, 3-methylresorcinol, 4-methylresorcinol, and methylhydroquinone. The standard (p 0 =0.1MPa) molar enthalpies of formation, in the crystalline phase, at T = 298.15 K, of the compounds mentioned above were derived from their standard massic energies of combustion, measured by static-bomb combustion calorimetry, while the standard molar enthalpies of sublimation of those compounds were obtained by the temperature dependence of their vapour pressures determined by the Knudsen effusion technique. From experimental values, the standard molar enthalpies of formation of the studied methylbenzenediols in the gaseous phase, at T = 298.15 K were then derived. The results are interpreted in terms of structural contributions to the energetics of the substituted benzenediols and compared with the same parameters estimated from the Cox Scheme. Moreover, the standard (p 0 =0.1MPa) molar enthalpies, entropies, and Gibbs energies of sublimation, at T = 298.15 K, were derived for the four isomers of methylbenzenediols.

  15. Temporal abscess after third molar extraction in the mandible.

    Science.gov (United States)

    de Oliveira Neto, Patrício José; de Souza Maliska, Maximiana Cristina; Sawazaki, Renato; Asprino, Luciana; de Moraes, Márcio; Moreira, Roger William Fernandes

    2012-03-01

    Dental infections resulting before or after third molar removal are complications in which the maxillofacial surgeon may have to initiate an earlier management. The severe dental infections resulting before or after this procedure is one of the few life-threatening complications in which the maxillofacial surgeon may have to initiate an earlier management. Infections involving the temporal space are rare and infrequently reported. Infections in this space have also been observed secondary to maxillary sinusitis, maxillary sinus fracture, temporomandibular arthroscopy, and drug injection, although more commonly associated to third molar infections. A 22-year-old man had undergone extraction of tooth 38 secondary to pericoronaritis by a general dentist. Physical examination of his face demonstrated severe trismus, pain, and swelling in temporal region. A CT scan showed an inflammatory area into the temporal space. He was started on IV cephalosporin, but the clinical course of the patient was not satisfactory. Incision and drainage were performed from an extraoral and intraoral approach. After discharged, the antibiotic was switched to clindamycin IO 600 mg. The retromaxillary and temporal infections are quite common after maxillary molar extractions but not after mandibular third molar, the spread mechanism of ascension must be involved with the virulence of microorganisms, but more studies are necessary to clarify this occurrence.

  16. excess molar volumes, and refractive index of binary mixtures

    African Journals Online (AJOL)

    Preferred Customer

    because (a) water molecules have hydroxyl group which can make stronger hydrogen bonding than methanol and (b) water molecules and glycerol have suitable kinetic energy for bulk volumes at high temperature. Thus, the mixture of glycerol + water have big excess molar volume than methanol. The hydrogen bonding ...

  17. Molar extinction coefficients of solutions of some organic compounds

    Indian Academy of Sciences (India)

    (C4H8O2), succinimide (C4H5NO2) as estimated from the measured absorbance of. 7 radiations in their ... species in the solution and ε is called the molar absorptivity or extinction coefficient. (l mol-1cm-1 or ... Integration of eq. (4) leads to.

  18. Lower molar and incisor displacement associated with mandibular remodeling.

    Science.gov (United States)

    Baumrind, S; Bravo, L A; Ben-Bassat, Y; Curry, S; Korn, E L

    1997-01-01

    The purpose of this study was to quantify the amount of alveolar modeling at the apices of the mandibular incisor and first molar specifically associated with appositional and resorptive changes on the lower border of the mandible during growth and treatment. Cephalometric data from superimpositions on anterior cranial base, mandibular implants of the Björk type, and anatomical "best fit" of mandibular border structures were integrated using a recently developed strategy, which is described. Data were available at annual intervals between 8.5 and 15.5 years for a previously described sample of approximately 30 children with implants. The average magnitudes of the changes at the root apices of the mandibular first molar and central incisor associated with modeling/remodeling of the mandibular border and symphysis were unexpectedly small. At the molar apex, mean values approximated zero in both anteroposterior and vertical directions. At the incisor apex, mean values approximated zero in the anteroposterior direction and averaged less than 0.15 mm/year in the vertical direction. Standard deviations were roughly equal for the molar and the incisor in both the anteroposterior and vertical directions. Dental displacement associated with surface modeling plays a smaller role in final tooth position in the mandible than in the maxilla. It may also be reasonably inferred that anatomical best-fit superimpositions made in the absence of implants give a more complete picture of hard tissue turnover in the mandible than they do in the maxilla.

  19. Dental caries pattern of first and second permanent molars and ...

    African Journals Online (AJOL)

    Objective: The study was carried out to assess the dental caries pattern of first and second permanent molars and treatment needs among adolescent Nigerians in Lagos. Method: Examinations for dental caries and treatment needs in accordance with the criteria of the World Health Organization Basic Methods for oral ...

  20. Piezosurgery versus Rotatory Osteotomy in Mandibular Impacted Third Molar Extraction

    Science.gov (United States)

    Bhati, Bharat; Kukreja, Pankaj; Kumar, Sanjeev; Rathi, Vidhi C.; Singh, Kanika; Bansal, Shipra

    2017-01-01

    Aim: The aim of this study is to compare piezoelectric surgery versus rotatory osteotomy technique in removal of mandibular impacted third molar. Materials and Methods: Sample size of 30 patients 18 males, 12 females with a mean age of 27.43 ± 5.27. Bilateral extractions were required in all patients. All the patients were randomly allocated to two groups in one group, namely control group, surgical extraction of mandibular third molar was done using conventional rotatory osteotomy and in the other group, namely test group, extraction of lower third molar was done using Piezotome. Results: Parameters assessed in this study were – mouth opening (interincisal opening), pain (visual analog scale VAS score), swelling, incidence of dry socket, paresthesia and duration of surgery in both groups at baseline, 1st, 3rd, and 7th postoperative day. Comparing both groups pain scores with (P piezosurgery group (51.40 ± 17.9) minutes compared to the conventional rotatory group with a mean of (37.33 ± 15.5) minutes showing a statistically significant difference (P = 0.002). Conclusion: The main advantages of piezosurgery include soft tissue protection, optimal visibility in the surgical field, decreased blood loss, less vibration and noise, increased comfort for the patient, and protection of tooth structures. Therefore, the piezoelectric device was efficient in decreasing the short-term outcomes of pain and swelling although taking longer duration than conventional rotatory technique it significantly reduces the associated postoperative sequelae of third molar surgery. PMID:28713729

  1. Molar Intubation for Intra Oral Swellings:Our Experience

    Directory of Open Access Journals (Sweden)

    Meenoti Potdar

    2008-01-01

    Full Text Available Molar intubation is a technique of laryngoscopy that can be used for anticipated difficult intubation in cases where standard laryngoscopy technique is difficult due to presence of any intraoral mass that anatomically hampers laryngoscopy or that bleeds on touch. This technique is very easy, reliable and rewarding but should be practiced on normal patients for easy application in actual difficult cases.

  2. Molar extinction coefficients of some carbohydrates in aqueous ...

    Indian Academy of Sciences (India)

    of plants and animals, both as structural elements and in the maintenance of functional ... In this paper we report the molar extinction coefficient ε, of carbohydrates ... as the area, which has to be hit by the photons in order to cause interaction.

  3. Fracture Resistance Force of Primary Molar Crowns Milled from ...

    African Journals Online (AJOL)

    2018-04-04

    Apr 4, 2018 ... molar stainless steel crown (SSC) and stored in water at 37°C for 30 days. The crowns were seated on Cr‑Co ... model) or chairside (in‑office system model) CAD/ ..... crowns, deformation may be observed instead of fracture.

  4. Canal pattern in mesiobuccal root of maxillary molars of Nigerians ...

    African Journals Online (AJOL)

    planed maxillary first and second molars respectively were sectioned transversely at three different points corresponding to the cemento-enamel junction, the peak of the external outline of the furcation and the margin of the middle and apical thirds ...

  5. Unilateral maxillary molar distalization with zygoma-gear appliance.

    Science.gov (United States)

    Kilkis, Dogan; Bayram, Mehmet; Celikoglu, Mevlut; Nur, Metin

    2012-08-01

    The aim of this study was to present the orthodontic treatment of a 15-year-old boy with a unilateral maxillary molar distalization system, called the zygoma-gear appliance. It consisted of a zygomatic anchorage miniplate, an inner bow, and a Sentalloy closed coil spring (GAC International, Bohemia, NY). A distalizing force of 350 g was used during the distalization period. The unilateral Class II malocclusion was corrected in 5 months with the zygoma-gear appliance. The maxillary left first molar showed distalization of 4 mm with an inclination of 3°. The maxillary premolars moved distally with the help of the transseptal fibers. In addition, there were slight decreases in overjet (-0.5 mm) and maxillary incisor inclination (-1°), indicating no anchorage loss from the zygoma-gear appliance. Preadjusted fixed appliances (0.022 × 0.028-in, MBT system; 3M Unitek, Monrovia, Calif) were placed in both arches to achieve leveling and alignment. After 14 months of unilateral distalization with the zygoma-gear appliance and fixed appliances, Class I molar and canine relationships were established with satisfactory interdigitation of the posterior teeth. Acceptable overjet and overbite were also achieved. This article shows that this new system, the zygoma-gear appliance, can be used for unilateral maxillary molar distalization without anchorage loss. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  6. Distribution and characteristics of molar-incisor hypomineralization

    Directory of Open Access Journals (Sweden)

    Janković Svjetlana

    2014-01-01

    Full Text Available Background/Aim. Developmental disorders of teeth are the problems that are becoming more present in pediatric dentistry, especially on first permanent molars and incisors. Molar Incisor Hypomineralization (MIH is proposed term for this phenomenon. The aim of this study was to establish the MIH prevalence in children living in the Foča municipality (Bosnia and Herzegovina as well as to assess characteristics and expression of hypomineralization within the tested population. Methods. A total of 141 children from the Foča municipality, 8 years of age, were included in this study. Criteria according to Weerhejm have been used for diagnosis of hypomineralization: demarcated opacity (DO, post-eruptive breakdown (PEB, atypical restoration (AR, extracted molars due to MIH (E-MIH and unerupted tooth (UT. Level and the prominence of color changes have been determined for patients with DO, PEB and AR. Results. MIH in this area was present in 12.8% of children. The prevalence of MIH changes expressed in percentages was as follows: DO was at 9.2%, PEB in 3.5%, AR in 5.6%, while E-MIH was 5.6%. A total of 9.9% of the examinees had mild, 5.6% moderate, and 7.8% severe form of MIH. White form of MIH defects was found in 9.9% of the examinees, white-yellow one in 5.6% and yellow-brown color in 3.5% of the examined children. These changes were more often present in the lower jaw (60.3%. In total, 6.4% of children had these changes present only on molars, while 6.4% of them both on molars and incisors simultaneously. Conclusion. A total of 12.8% of the examinees with MIH is not to be disregarded. With timely diagnosis, prevention and therapy complications could be avoided or mitigated.

  7. Three-dimensional space changes after premature loss of a maxillary primary first molar.

    Science.gov (United States)

    Park, Kitae; Jung, Da-Woon; Kim, Ji-Yeon

    2009-11-01

    A space maintainer is generally preferred when a primary first molar is lost before or during active eruption of the first permanent molars in order to prevent space loss. However, controversy prevails regarding the space loss after eruption of the permanent first molars. The purpose of this study was to examine spatial changes subsequent to premature loss of a maxillary primary first molar after the eruption of the permanent first molars. Thirteen children, five girls and eight boys, expecting premature extraction of a maxillary primary first molar because of caries and/or failed pulp therapy, were selected. Spatial changes were investigated using a three-dimensional laser scanner by comparing the primary molar space, arch width, arch length, and arch perimeter before and after the extraction of a maxillary primary first molar. Also, the inclination and angulation changes in the maxillary primary canines, primary second molars, and permanent first molars adjacent to the extraction site were investigated before and after the extraction of the maxillary primary first molar in order to examine the source of space loss. There was no statistically significant space loss on the extraction side compared to the control side (P = 0.33). No consistent findings were seen on the inclination and angulation changes on the extraction side. The premature loss of a maxillary primary first molar, in cases with class I molar relationship, has limited influence on the space in permanent dentition.

  8. Internal structure of mandible around mandibular molar using computed tomography. Anatomical consideration of molar anchorage in orthodontic treatment

    International Nuclear Information System (INIS)

    Enomoto, Yutaka; Yamashita, Daisuke; Saito, Katsuhiko; Kasai, Kazutaka

    2008-01-01

    For establishment of fine occlusion, facial profile and oral function in orthodontic treatment, molar anchorage in teeth movement is important manner in extracted cases. The aims of this study were to investigate the relationship between facial morphology and internal structure of mandibular body in molar region by computer tomography, and to discuss about molar anchorage in orthodontic treatment. The data for this study were obtained from 35 modern male Japanese skulls (mean age; 27 year-old, ranged from 18 year-old to 47 year-old). Measurement variables were FMA, SN to mandibular plane angle, gonial angle, alveolar breadth, cortical bone thickness of buccal and lingual sides, and the distance between dental root and cortical bone. As a result, alveolar breadth and the distance between dental root and cortical bone were narrow in long facial type, on the contrary, these variables were wide in short facial type. The result suggested that these variables were considered important factors as molar anchorage in extracted cases. (author)

  9. Acute inflammation in horizontal incompletely impacted third molar with radiolucency in the elderly

    Directory of Open Access Journals (Sweden)

    Minoru Yamaoka

    2009-07-01

    Full Text Available Minoru Yamaoka, Yusuke Ono, Masahiro Takahashi, Masahide Ishizuka, Takayuki Uchihashi, Kouichi Yasuda, Takashi Uematsu, Kiyofumi FurusawaMatsumoto Dental University, Oral and Maxillofacial Surgery, Shiojiri, Nagano, JapanAbstract: Although radiolucency has been shown as a risk of infection, the poorly understood effects of aging on radiolucency correlate with acute pericoronitis, which has a high risk of infection extending any complications. We reviewed the records of 346 consecutive patients aged more than 41 years to evaluate whether pericoronal radiolucency below the crown in mandibular horizontal incompletely impacted third molars is related to acute inflammation. The frequency of acute inflammation in teeth with pericoronal radiolucency below the crown was similar to that in teeth without; however, the odds ratio of acute inflammation exhibited in women aged more than 61 years compared to women aged 41–50 years was 9.77 (95% confidence interval [CI]: 1.67–57.29; P <<0.05, and in women aged more than 61 years compared to women aged 51–60 years was 26.25 (95% CI: 2.94–234.38; P < 0.01. The odds ratio of severe acute inflammation exhibited in men aged more than 61 years compared to men aged 41–50 years was 16.67 (95% CI: 1.76–158.27; P < 0.01. These odds ratios indicate an association of acute pericoronitis, including the severe forms of acute inflammation that result from pericoronitis, with pericoronal radiolucency below the crown in the elderly.Keywords: radiolucency, mandible, third molar, acute inflammation, aging

  10. Molaren Inzisiven Hypomineralisation und Milchmolaren Hypomineralisation - klinisches Erscheinungsbild, Prävalenz und deren Ursachen - Molar Incisor Hypomineralisation and Deciduous Molar Hypomineralisation - clinical appearance, prevalence and determinants for its occurrence

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Weerheijm, K.L.

    2012-01-01

    Background: Molar Incisor Hypomineralisation (MIH) and Deciduous Molar Hypomineralisation (DMH) are frequently occurring dental problems in children. Children with MIH have demarcated opacities in their erupting first permanent molars often in combination with demarcated opacities in their permanent

  11. Hydrogen bonding interactions between ethylene glycol and water: density, excess molar volume, and spectral study

    Institute of Scientific and Technical Information of China (English)

    ZHANG JianBin; ZHANG PengYan; MA Kai; HAN Fang; CHEN GuoHua; WEI XiongHui

    2008-01-01

    Studies of the density and the excess molar volume of ethylene glycol (EG)-water mixtures were carried out to illustrate the hydrogen bonding interactions of EG with water at different temperatures, The re-sults suggest that a likely complex of 3 ethylene glycol molecules bonding with 4 water molecules in an ethylene glycol-water mixture (EGW) is formed at the maximal excess molar volume, which displays stronger absorption capabilities for SO2 when the concentration of SO2 reaches 400×106 (volume ratio) in the gas phase. Meanwhile, FTIR and UV spectra of EGWs were recorded at various EG concentra-tions to display the hydrogen bonding interactions of EG with water. The FTIR spectra show that the stretching vibrational band of hydroxyl in the EGWs shifts to a lower frequency and the bending vibra-tional band of water shifts to a higher frequency with increasing the EG concentration, respectively. Furthermore, the UV spectra show that the electron transferring band of the hydroxyl oxygen in EG shows red shift with increasing the EG concentration. The frequency shifts in FTIR spectra and the shifts of absorption bands in UV absorption spectra of EGWs are interpreted as the strong hydrogen bonding interactions of the hydrogen atoms in water with the hydroxyl oxygen atoms of EG.

  12. Occlusal relief changes with molar wear in Pan troglodytes troglodytes and Gorilla gorilla gorilla.

    Science.gov (United States)

    M'kirera, Francis; Ungar, Peter S

    2003-06-01

    Most research on primate tooth form-function relationships has focused on unworn teeth. This study presents a morphological comparison of variably worn lower second molars (M(2)s) of lowland gorillas (Gorilla gorilla gorilla; n=47) and common chimpanzees (Pan troglodytes troglodytes; n=54) using dental topographic analysis. High-resolution replicas of occlusal surfaces were prepared and scanned in 3D by laser scanning. The resulting elevation data were used to create a geographic information system (GIS) for each tooth. Occlusal relief, defined as the ratio of 3D surface area to 2D planometric area of the occlusal table, was calculated and compared between wear stages, taxa, and sexes. The results failed to show a difference in occlusal relief between males and females of a given taxon, but did evince differences between wear stages and between taxa. A lack of significant interaction between wear stage and taxon factors suggests that differences in occlusal relief between chimpanzees and gorillas are maintained throughout the wear sequence. These results add to a growing body of information on how molar teeth change with wear, and how differences between primate species are maintained at comparable points throughout the wear sequence. Such studies provide new insights into form-function relationships, which will allow us to infer certain aspects of diet in fossils with worn teeth.

  13. A morphological study of the mandibular molar region using reconstructed helical computed tomographic images

    International Nuclear Information System (INIS)

    Tsuno, Hiroaki; Noguchi, Makoto; Noguchi, Akira; Yoshida, Keiko; Tachinami, Yasuharu

    2010-01-01

    This study investigated the morphological variance in the mandibular molar region using reconstructed helical computed tomographic (CT) images. In addition, we discuss the necessity of CT scanning as part of the preoperative assessment process for dental implantation, by comparing the results with the findings of panoramic radiography. Sixty patients examined using CT as part of the preoperative assessment for dental implantation were analyzed. Reconstructed CT images were used to evaluate the bone quality and cross-sectional bone morphology of the mandibular molar region. The mandibular cortical index (MCI) and X-ray density ratio of this region were assessed using panoramic radiography in order to analyze the correlation between the findings of the CT images and panoramic radiography. CT images showed that there was a decrease in bone quality in cases with high MCI. Cross-sectional CT images revealed that the undercuts on the lingual side in the highly radiolucent areas in the basal portion were more frequent than those in the alveolar portion. This study showed that three-dimensional reconstructed CT images can help to detect variances in mandibular morphology that might be missed by panoramic radiography. In conclusion, it is suggested that CT should be included as an important examination tool before dental implantation. (author)

  14. Relationship of third molar movement during orthodontic treatment and root angulation

    Directory of Open Access Journals (Sweden)

    Morteza Oshagh

    2012-01-01

    Conclusion: The relation between the amount of third molar movement and its root angulation was not statistically significant. Therefore movement of third molars during orthodontic treatment should not be assumed as an etiologic factor of root angulations.

  15. C-reactive protein a better indicator of inflammation after third molar ...

    African Journals Online (AJOL)

    operative pain and pre-operative levels of C-reactive and post-operative pain and swelling in impacted third molar surgery. Materials and Methods: In this prospective study subjects were patients indicated for mandibular third molar extraction.

  16. Outcomes of intentionally replanted molars according to preoperative locations of periapical lesions and the teeth

    Directory of Open Access Journals (Sweden)

    WooCheol Lee

    2012-06-01

    Conclusions: Within the limitations of this study, IR of mandibular molars seemed to provide a higher success rate than that for maxillary molars, regardless of the presence of preoperative periapical lesions.

  17. MMP20 Overexpression Disrupts Molar Ameloblast Polarity and Migration.

    Science.gov (United States)

    Shin, M; Chavez, M B; Ikeda, A; Foster, B L; Bartlett, J D

    2018-02-01

    Ameloblasts responsible for enamel formation express matrix metalloproteinase 20 (MMP20), an enzyme that cleaves enamel matrix proteins, including amelogenin (AMELX) and ameloblastin (AMBN). Previously, we showed that continuously erupting incisors from transgenic mice overexpressing active MMP20 had a massive cell infiltrate present within their enamel space, leading to enamel mineralization defects. However, effects of MMP20 overexpression on mouse molars were not analyzed, although these teeth more accurately represent human odontogenesis. Therefore, MMP20-overexpressing mice ( Mmp20 +/+ Tg + ) were assessed by multiscale analyses, combining several approaches from high-resolution micro-computed tomography to enamel organ immunoblots. During the secretory stage at postnatal day 6 (P6), Mmp20 +/+ Tg + mice had a discontinuous ameloblast layer and, unlike incisors, molar P12 maturation stage ameloblasts abnormally migrated away from the enamel layer into the stratum intermedium/stellate reticulum. TOPflash assays performed in vitro demonstrated that MMP20 expression promoted β-catenin nuclear localization and that MMP20 expression promoted invasion through Matrigel-coated filters. However, for both assays, significant differences were eliminated in the presence of the β-catenin inhibitor ICG-001. This suggests that MMP20 activity promotes cell migration via the Wnt pathway. In vivo, the unique molar migration of amelogenin-expressing ameloblasts was associated with abnormal deposition of ectopic calcified nodules surrounding the adherent enamel layer. Enamel content was assessed just prior to eruption at P15. Compared to wild-type, Mmp20 +/+ Tg + molars exhibited significant reductions in enamel thickness (70%), volume (60%), and mineral density (40%), and MMP20 overexpression resulted in premature cleavage of AMBN, which likely contributed to the severe defects in enamel mineralization. In addition, Mmp20 +/+ Tg + mouse molar enamel organs had increased levels

  18. Space loss following premature loss of primary second molars.

    Science.gov (United States)

    Alnahwi, Hassan H; Donly, Kevin J; Contreras, Claudia I

    2015-01-01

    This study was designed to evaluate the amount of space loss (SL) caused by premature loss of primary second molars, determine whether the eruption status of permanent first molars is an important factor in the amount of SL, and evaluate the effectiveness of space maintainers (SMs) in SL prevention. SL associated with 100 prematurely extracted primary second molars was evaluated in 87 healthy patients. Teeth were divided into groups based on the use of SMs (36 with SM and 64 without SM). Bitewing and periapical radiographs taken before extraction and 6, 12, 24, 36, and 48 months after extraction were used to determine the amount of SL. Not every patient attended every recall appointment, so the sample size varied at different evaluation times. The most significant amount of SL occurred in the first 12 months after extraction. In patients who did not use an SM, at 6 months there was a mean SL of 2.12 mm (SD, 1.65 mm) and at 12 months there was a mean of 4.02 mm (SD, 1.65), with significantly more SL in the first 6 months (P 0.05). When patients without an SM were grouped by the eruption status of the permanent first molar, there was significantly more SL in the groups with unerupted first molars than there was in the groups with erupted first molars at both 6 months (P < 0.001) and 12 months (P < 0.05). At both 6 and 12 months, the amount of SL in patients who had an SM (n = 13 and n = 14, respectively) was not significantly different from the amount of SL in those who did not have an SM (n = 33 and n = 23, respectively). SMs should be placed as soon as possible following tooth extraction to prevent undue SL. Placement of an SM a year or more after extraction has minimal benefit, since most SL takes place within the first year. SL does occur even when SMs are used.

  19. Roentgenographic studies on the growth and development of lower third molars in Korean female

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyoung Soon; Lee, Sung Woo [Department of Dental Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1976-11-15

    The author obtained the following results through the studies on 1012 roentgenograms of lower third molar regions of Korean female; 1. The rate of presence of lower third molars was 78.9 percent. 2. The period that crowns of lower third molars become completed was 16.1 years. 3. The period that completion of apices of lower third molars become completed was over 27 years.

  20. Endodontic Treatment of a Maxillary Second Molar with Developmental Anomaly: A Case Report

    OpenAIRE

    Asgary, Saeed

    2007-01-01

    Fusion is a rare occurrence in molar teeth. The purpose of this rare case presentation is to describe the nonsurgical endodontic treatment of maxillary molar. A 28-year-old patient was referred for endodontic treatment of her chronic apical abscess of right maxillary second molar. In the clinical examination, a sinus tract adjacent to involved tooth and a small crown of supernumerary tooth fused to the buccal surface of the molar at gingival margin was observed. Endodontic treatment was decid...

  1. A study of the eruption of the mandibular first permanent molar

    OpenAIRE

    河野, 美砂子; Kohno, Misako

    1995-01-01

    The object of this study was to know what positional changes of the mandibular first permanent molars occur just before their gingival emergence. The eruptive process of the mandibular first molars was investigated during the period from alveolareruption to preoraleruption. The subjects were 14 patients whose second primary molars were prematurely lost in one side and remained on the other side. Longitudinal oblique cephalograms were used to estimate the eruptive process of the first molars o...

  2. Co-relation of variables as determined from panoramic radiograph and evaluating their significance in eruption of permanent mandibular third molar

    Directory of Open Access Journals (Sweden)

    Kushal Amin

    2008-01-01

    Full Text Available Purpose of the Study: Purpose of the study is to investigate whether the variables associated with the permanent mandibular third molar (PMM3 and arch dimensions could be co-related and significantly differentiated between a fully erupted and mesially impacted PMM3 among a set of Indian population. Study Design: A standardized panoramic radiograph was taken of subjects of age 21 years and above. Patients with missing tooth from mandibular arch, subjects undergoing or having history of orthodontic treatment, subjects having disto-angular, horizontal or vertical impacted PMM3 were excluded from the study. Subjects were divided into 2 groups: (1 mesially impacted PMM3 and (2 vertically erupted PMM3. Following measurements were taken from acetate paper tracing of standardized panoramic radiograph: (1 Angulation of long axis of PMM3 to permanent mandibular second molar (theta (2 Angulation of PMM 3 to base of mandible (theta 2 (3 Gonial angle (theta 3 (4 Mesio-distal width of PMM 3 (5 Retro molar space. From these measurements Ganss ratio (retro molar space /PMM3 crown width. was calculated. Results and Conclusion: Results revealed that angle theta 1, angle theta 2, retro molar space and Ganss ratio were positively co-related and highly significant variables associated with the mesially and vertically erupted teeth as measured on panoramic radiograph. Using these variables a long-term study can be carried out to predict the ultimate position of lower third molar in the arch so that if there is a probability of the tooth being impacted at a later age, a prophylactic germectomy can be performed at an early age.

  3. Immediate Placement of Ultrawide-Diameter Implants in Molar Sockets: Description of a Recommended Technique

    NARCIS (Netherlands)

    Hattingh, A.C.; Bruyn, H. de; Ackermann, A.; Vandeweghe, S.

    2018-01-01

    Immediate implant placement is performed less frequently in molar extraction sockets than in single root sockets. This is mainly due to the tripodal anatomical configuration of molar roots, which is perceived as complex and therefore unsuitable. The mechanical burden of molar sites, combined with

  4. The origin of the lower fourth molar in canids, inferred by individual variation

    Directory of Open Access Journals (Sweden)

    Masakazu Asahara

    2016-11-01

    Full Text Available Background An increase in tooth number is an exception during mammalian evolution. The acquisition of the lower fourth molar in the bat-eared fox (Otocyon megalotis, Canidae, Carnivora, Mammalia is one example; however, its developmental origin is not clear. In some canids (Canidae, individual variation exist as supernumerary molar M4. This study focuses on the acquisition of the lower fourth molar in canids and proposes that the inhibitory cascade model can explain its origin. Methods Occlusal view projected area of lower molars was determined from 740 mandibles obtained from Canis latrans, Nyctereutes procyonoides, and Urocyon cinereoargenteus museum specimens. For each molar, relative sizes of molars (M2/M1 and M3/M1 scores affected by inhibition/activation dynamics during development, were compared between individuals with and without supernumerary molar (M4. Results Possession of a supernumerary molar was associated with significantly larger M2/M1 score in Canis latrans, M3/M1 score in Nyctereutes procyonoides, and M2/M1 and M3/M1 scores in Urocyon cinereoargenteus compared to individuals of these species that lacked supernumerary molars. Discussion We propose that, in canids, the supernumerary fourth molar is attributable to reduced inhibition and greater activation during molar development. In the bat-eared fox, altered inhibition and activation dynamics of dental development during omnivorous-insectivorous adaptation may be a contributing factor in the origin of the lower fourth molar.

  5. MicroCT study on the enamel mineral density of primary molars

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Kalin, K.; van Ruijven, L.J.; ten Cate, J.M.; Veerkamp, J.S.J.

    2016-01-01

    Aim The aim of this study is to report on the mineral density of the enamel of primary molars related to the age of the child and to compare the mineral density of sound and carious enamel in those molars. Materials and methods This study included 23 children and 41 extracted primary molars. The

  6. Prevalence of cheese molars in eleven-year-old Dutch children.

    Science.gov (United States)

    Weerheijm, K L; Groen, H J; Beentjes, V E; Poorterman, J H

    2001-01-01

    In the Netherlands, first permanent molars with idiopathic enamel disturbances (IED) are called cheese molars. Though concern is expressed about their prevalence, adequate figures on the subject are missing. The porous enamel of cheese molars can be very sensitive to cold air and can decay rapidly. The aim of the present study was to investigate the prevalence in eleven-year-old Dutch children of cheese molars (IED). During an epidemiological study performed in four cities in the Netherlands, the first permanent molars and central incisors of eleven-year-old children were examined for hypoplasia, opacities, posteruptive enamel loss, premature extraction, and atypical restorations. The observation of a hypoplasia excluded the possibility of cheese molar. A total of 497 children were examined. Six percent (n = 128) of the molars (n = 1988) showed signs of IED (cheese molars), 10 percent of the children had cheese molars of which 8 percent two or more. Incisors (4 percent) with opacities were found in 3 percent in combination with two or more cheese molars. Among the four cities, no significant differences in occurrence were found. The results of this study showed that in 10 percent of the Dutch children eleven years of age, cheese molars (IED) were found. The cause for the phenomenon called cheese molars appears to be child centered. Further studies on prevalence, causes and prevention are mandatory.

  7. Partial molar volume of anionic polyelectrolytes in aqueous solution.

    Science.gov (United States)

    Salamanca, Constain; Contreras, Martín; Gamboa, Consuelo

    2007-05-15

    In this work the partial molar volumes (V) of different anionic polyelectrolytes and hydrophobically modified polyelectrolytes (PHM) were measured. Polymers like polymaleic acid-co-styrene, polymaleic acid-co-1-olefin, polymaleic acid-co-vinyl-2-pyrrolidone, and polyacrylic acid (abbreviated as MAS-n, PA-n-K2, AMVP, and PAA, respectively) were employed. These materials were investigated by density measurements in highly dilute aqueous solutions. The molar volume results allow us to discuss the effect of the carboxylic groups and the contributions from the comonomeric principal chain. The PAA presents the smaller V, while the largest V value was for AMVP. The V of PHM shows a linear relationship with the number of methylene groups in the lateral chain. It is found that the magnitude of the contribution per methylene group decreases as the hydrophobic character of the environment increases.

  8. Standard molar enthalpies of formation of sodium alkoxides

    International Nuclear Information System (INIS)

    Chandran, K.; Srinivasan, T.G.; Gopalan, A.; Ganesan, V.

    2007-01-01

    The molar enthalpies of solution of sodium in methanol, ethanol, and n-propanol and of sodium alkoxides in their corresponding alcohols were measured at T=298.15K using an isoperibol solution calorimeter. From these results and other auxiliary data, the standard molar enthalpies of formation, Δ f H m o (RONa,cr) of sodium methoxide, sodium ethoxide, and sodium n-propoxide were calculated and found to be {(-366.21+/-1.38) (-413.39+/-1.45), and (-441.57+/-1.18)}kJ.mol -1 , respectively. A linear correlation has been found between Δ f H m o (RONa)andΔ f H m o (ROH) for R=n-alkyl, enabling the prediction of data for other sodium alkoxides

  9. Maxillary second molar with four roots and five canals

    Directory of Open Access Journals (Sweden)

    Xinjia Sha

    2018-06-01

    Full Text Available In this case report, we present a maxillary second molar variant, which had two palatal roots with two canals and two buccal roots with three canals, including a second mesiobuccal canal. A 44-year-old female patient complained about a tooth crown fracture and severe pain in her right maxillary second molar. A clinical intraoral inspection and radiography were carried out on the tooth, and a diagnosis of chronic apical periodontitis was made. Four roots (two buccal and two palatal and five canals (three buccal and two palatal were found. The anatomical variation of the tooth was further confirmed by cone-beam computed tomography, a cone-fit procedure, and a radiograph with a shifted projection angle. Root-canal treatment was performed under an endodontic microscope.

  10. Pulpal responses to cavity preparation in aged rat molars

    OpenAIRE

    Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato; 大島, 勇人

    2006-01-01

    The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, there are few available data concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense of aged pulp by investigating the responses of odontoblasts and class II major histocompatibility complex (MHC)-positive cells to cavity preparation in aged rat molars (300-360 d) and comparing the results with those in young adult rats (100...

  11. Management of third molar teeth from an endodontic perspective

    OpenAIRE

    Hany Mohamed Aly Ahmed

    2012-01-01

    Third molar teeth are subject to many dental complications because of their most posterior location, aberrant occlusal anatomy and abnormal eruption patterns. Owing to these anatomical limitations, their extraction remains the treatment of choice for many dental practitioners. Despite being a common dental procedure, minimum intervention and retaining every functional component of the dental arch are of prime importance in contemporary dental practice. As such, this review aims to discuss the...

  12. Distal displacement of the maxilla and the upper first molar.

    Science.gov (United States)

    Baumrind, S; Molthen, R; West, E E; Miller, D M

    1979-06-01

    Data from a sample of 198 Class II cases treated with various appliances which deliver distally directed forces to the maxilla were examined to determine the frequency of absolute distal displacement of the upper first molar and of the maxilla. Analysis revealed that such distal displacement is possible and that it is, in fact, a frequent finding following treatment. Long-range stability of distal displacement was not assessed.

  13. In vivo Dentin Caries Model using Rat Molars

    OpenAIRE

    Takashi, HIGASHI; Junji, TAGAMI; Nobuhiro, HANADA; Cariology and Operative Dentistry, Department of Restorative Sciences, Tokyo Medical and Dental University; Cariology and Operative Dentistry, Department of Restorative Sciences, Tokyo Medical and Dental University; Department of Oral Science The National Institute of Infectious Diseases(NIID)

    2000-01-01

    Experimental dentinal caries was induced in rat molars which were inoculated orally with Streptococcus mutans and maintained on a carionenic diet 2000. After 30 days on the diet, the rats were sacrificed. The caries lesions were confirmed with a caries detector, then nanohardness determination of caries dentin were measured with nanoindentation. After hardness measurement, the lesion was examined by SEM and EDS. Dentin caries in sixteen fissures was induced among 20 fissures in the mandibular...

  14. Fate of the Molar Dental Lamina in the Monophyodont Mouse

    Science.gov (United States)

    Dosedělová, Hana; Dumková, Jana; Lesot, Hervé; Glocová, Kristýna; Kunová, Michaela; Tucker, Abigail S.; Veselá, Iva; Krejčí, Pavel; Tichý, František; Hampl, Aleš; Buchtová, Marcela

    2015-01-01

    The successional dental lamina (SDL) plays an essential role in the development of replacement teeth in diphyodont and polyphyodont animals. A morphologically similar structure, the rudimental successional dental lamina (RSDL), has been described in monophyodont (only one tooth generation) lizards on the lingual side of the developing functional tooth. This rudimentary lamina regresses, which has been proposed to play a role in preventing the formation of future generations of teeth. A similar rudimentary lingual structure has been reported associated with the first molar in the monophyodont mouse, and we show that this structure is common to all murine molars. Intriguingly, a lingual lamina is also observed on the non-replacing molars of other diphyodont mammals (pig and hedgehog), initially appearing very similar to the successional dental lamina on the replacing teeth. We have analyzed the morphological as well as ultrastructural changes that occur during the development and loss of this molar lamina in the mouse, from its initiation at late embryonic stages to its disappearance at postnatal stages. We show that loss appears to be driven by a reduction in cell proliferation, down-regulation of the progenitor marker Sox2, with only a small number of cells undergoing programmed cell death. The lingual lamina was associated with the dental stalk, a short epithelial connection between the tooth germ and the oral epithelium. The dental stalk remained in contact with the oral epithelium throughout tooth development up to eruption when connective tissue and numerous capillaries progressively invaded the dental stalk. The buccal side of the dental stalk underwent keratinisation and became part of the gingival epithelium, while most of the lingual cells underwent programmed cell death and the tissue directly above the erupting tooth was shed into the oral cavity. PMID:26010446

  15. The maxillary second molar - anatomical variations (case report).

    Science.gov (United States)

    Beshkenadze, E; Chipashvili, N

    2015-01-01

    To be acquainted with dental anatomical specificity is of great importance for dental endodontic treatment algorithm. The subject of present publication is 2 clinical cases of upper second molars, detailed characterization of, which is considered very important for enrichment of anatomical knowledge about dental anatomical variations. In one case, the reason for admission to the clinic of a 38-year-old woman was complains as of esthetic character as well as functional misbalance (disturbance of chewing function due to the damage of orthopedic construction). The patient indicated to the existence of coronary defects of large size aesthetic discomforts, damage and discolouration of old orthopedic construction (denture) in maxillary right molar area. According to the data obtained after clinical and visiographical examinations, chronic periodontitis of 17 teeth was identified as a result of incomplete endodontic treatment. According to the data obtained after clinical and visiographical examinations, the diagnosis of chronic periodontitis of 17 teeth was identified, tooth 17 with 2 roots and 2 canals. In the second clinical case, the reason for admission to the clinic of a 39-year-old woman was severe pain in the upper right molar area. The patient indicated to the caries on the tooth 17. After completion of proper survey clinical and visiographical examinations, acute pulpitis (K04.00) - with three roots and 4 canals was diagnosed. In both cases after the proper examinations and agreement with the patients a treatment plan envisaging: 17 teeth endodontic treatment, filling of caries defects and their preparation on one hand for orthopedic construction (denture) and on the other hand for restoration of anatomical integrity by light-cured composite, was scheduled. The present study is designed to prevent complications of endodontic treatment of the second molar, to optimize diagnosis and treatment algorithm, once again proving reliable information indicating to the

  16. Determination of partial molar volumes from free energy perturbation theory.

    Science.gov (United States)

    Vilseck, Jonah Z; Tirado-Rives, Julian; Jorgensen, William L

    2015-04-07

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood-Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm(3) mol(-1). The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute-solvent interactions.

  17. Molar macrowear reveals Neanderthal eco-geographic dietary variation.

    Directory of Open Access Journals (Sweden)

    Luca Fiorenza

    Full Text Available Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources.

  18. 3-D diagnosis-assisted management of anomalous mandibular molar

    Directory of Open Access Journals (Sweden)

    Neelam Mittal

    2012-01-01

    Full Text Available This case report describes the successful non-surgical endodontic management of carious exposed three-rooted mandibular molar with four root canals detected on the pre-operative radiograph taken with 20 degrees mesial angulation and confirmed with a 64-slice helical computed tomography scan-assisted 3-D-reconstructed images. Access cavity shape was modified to locate the extra canal with respect to the distolingual root in the left mandibular first molar. Copious irrigation was accomplished with 5.25% sodium hypochlorite and 17% EDTA. Biomechanical preparation was done using protapers. Calcium hydroxide dressing was done for 1 week. The tooth was obturated using gutta percha and AH 26 root canal sealer, and it was permanently restored with composite. Clinical examination on follow-up visits revealed no sensitivity to percussion and palpation in the left mandibular first molar. Thorough knowledge of root canal variations and use of advanced diagnostic modalities lead to successful non-surgical management of the complex cases.

  19. Determination of partial molar volumes from free energy perturbation theory†

    Science.gov (United States)

    Vilseck, Jonah Z.; Tirado-Rives, Julian

    2016-01-01

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood–Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm3 mol−1. The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute–solvent interactions. PMID:25589343

  20. Variable permanent mandibular first molar: Review of literature

    Science.gov (United States)

    Ballullaya, Srinidhi V; Vemuri, Sayesh; Kumar, Pabbati Ravi

    2013-01-01

    Introduction: The success of root canal therapy depends on the locations of all the canals, thourough debridement and proper sealing. At times the clinicians are challenged with variations in morphology of root canal. This review article attempts to list out all the variations of permanent mandibular first molar published so for in the literature. Materials and Methods: An exhaustive search was undertaken using PUBMED database to identify published literature from 1900 to 2010 relating to the root canal morphology of permanent first molar by using key words. The selected artcles were obtained and reviewed. Results: Total ninty seven articles were selected out of which 50 were original article and forty seven were case reports. The incidence of third canal in mesial root was 0.95% to 15%. The incidence of three rooted mandibular first molar was 3% to 33%. Only ninety cases reported with c-shape canal configuration. Incidence of Taurodintism without congenital disorder was very rare. Conclusion: The root canal treatment requires proper knowlegde of variations in root canal morphology in order to recognise, disinfect and seal all portal of exit. This can be accomplished with proper diagnosis using newer modes, modification in access preparation, use of operating microscope, enhanced methods of disinfecting and sealing of all canals. PMID:23716959

  1. Interfacial Properties of Methylcelluloses: The Influence of Molar Mass

    Directory of Open Access Journals (Sweden)

    Pauline L. Nasatto

    2014-12-01

    Full Text Available The interfacial interactions of four methylcelluloses having the same average degree of substitution and distribution of methyl groups, but different molar masses, are studied at ambient temperature and at very low polymer concentrations. Firstly, the surface tension σ at the water/air interface is determined for the progressive addition of methylcellulose up to 100 mg/L; σ starts to decrease over 1 mg/L up to the critical aggregation concentration (CAC at 10 mg/L. The curves describing the influence of polymer concentration on σ are independent of the molar mass at equilibrium. Secondly, the adsorption of methylcellulose on silica particles is estimated from ζ-potential measurements. The data are interpreted in terms of an increase of the adsorbed layer thickness at the interface when the molar mass of methylcellulose increases. It is concluded that methylcellulose is adsorbed, forming trains and loops at the interface based on the equilibrium between surface free energy and solvent quality.

  2. Subcutaneous emphysema during third molar surgery: a case report.

    Science.gov (United States)

    Romeo, Umberto; Galanakis, Alexandros; Lerario, Francesco; Daniele, Gabriele Maria; Tenore, Gianluca; Palaia, Gaspare

    2011-01-01

    Extraction of third molars is the most common surgical procedure performed in oral surgery on a daily basis and, despite surgical skills and expertise, complications may occur. Complications observed during or after third molar removal may include pain, swelling, bleeding, infection, sinus perforation and nerve damage. Fortunately, with a proper management and a good surgical technique, the incidence of such events is low. Subcutaneous emphysema associated with dental extraction occurs when the air from the high-speed dental handpiece is forced into the soft tissue through the reflected flap and invades the adjacent tissues, leading to swelling, crepitus on palpation and occasionally spreading through the tissue spaces of the fascial planes. Although rare, iatrogenic subcutaneous emphysema can have serious and potentially life-threatening consequences. Care should be taken when using air-driven handpieces. The access of air into the facial tissues is not limited to tooth extractions, but may also occur through other portals of entrance, such as endodontically treated teeth, periodontium and lacerations of intraoral soft tissues. When subcutaneous emphysema occurs, it must be quickly diagnosed and properly managed to reduce the risk of further complications. This report presents a case of subcutaneous emphysema occurred during extraction of a mandibular third molar extraction with the use of an air turbine handpiece. Case management is described and issues relative to the diagnosis and prevention of this surgical complication are discussed.

  3. Incidence of trismus in transalveolar extraction of lower third molar

    Directory of Open Access Journals (Sweden)

    Gowri Balakrishnan

    2017-01-01

    Full Text Available Background: Conventional mandibular third molar removal produces tissue trauma that induces an inflammatory reaction, leading to postoperative sequelae, the most common ones being trismus which influences the patient's quality of life in the postoperative period. Identifying the factors determining trismus after mandibular third molar extraction helps us to evaluate and correlate the incidence of trismus with morphological and surgical factors that are associated with its incidence in the postoperative period. Methodology: Patients referred to our institution for surgical removal of their impacted lower third molar between November 2014 and February 2015 were the participants of the study. Type of impaction, indication, and level of difficulty based on Pedersen criteria were obtained. Postoperative pain, swelling, and mouth opening (MO limitations were evaluated at postoperative day (POD 0, POD1, POD3, POD5, and POD7 and were analyzed. P < 0.05 was considered statistically significant. Result and Conclusion: In this study, out of fifty patients, only nine patients had experienced limited MO during postoperative period when the duration of procedure exceeded 30 min. However, it occurred as cumulative of pericoronitis and tooth sectioning done. The postoperative trismus was more significant in disto-angular impaction (P < 0.05 due to postoperative sequelae, swelling and pain.

  4. The use of deciduous molars in EPR dose reconstruction

    International Nuclear Information System (INIS)

    El-faramawy, N.A.; Wieser, A.

    2005-01-01

    The use of deciduous teeth in EPR dose reconstruction has the unique potential to measure individual doses that were accumulated in the early childhood in the age up to 12 years. It was found previously that due to the small size of deciduous incisors, the available amount of enamel is not sufficient for EPR measurements. Therefore, dose assessment with deciduous incisors can only be done by measurement of whole teeth, including enamel and dentine. The measurement of whole teeth instead of enamel alone is possibly less reliable for dose reconstruction because the stability of CO 2 - radicals (that are an indicator for the absorbed dose) in biologically active dentine is not known. In the present study naturally loosed deciduous molars were investigated. The feasibility of separating enamel from small size molars was analysed. EPR spectrum parameters of whole molars and separated enamel only were evaluated before and after laboratory irradiation. The EPR signal amplitudes of the CO 2 - and native signals were determined by spectrum deconvolution, in dependence on radiation dose in the range 0.1 - 10 Gy. The fading at room temperature of native and CO 2 - EPR signals was analysed. The detection threshold for absorbed dose in enamel was determined.

  5. Evaluation of periodontal condition in intruded molars using miniscrews

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    Habib Ollah Ghanbari

    2015-12-01

    Full Text Available Introduction: The purpose of this preliminary study was to evaluate the periodontal condition of intruded molars in various phases of treatments. Methods: 30 patients with at least one overerupted upper first molar were selected. Upper molar bands with brackets were cemented. Two miniscrews were placed in the mesiopalatal and mesiobuccal aspect of the aforementioned teeth. A titanium molybdenum alloy (TMA spring was attached to the head of miniscrew in one end and ligated to the bracket in the other end to reach the predetermined force. Plaque index (PI, probing pocket depth (PPD, keratinized gingiva (KG, The distance between miniscrew (M.S and gingival level (GL, and bleeding on probing (BOP were recorded before loading and 1, 2, 3, 4 and 5 months post-loading .Results:  All patients completed the study and no complications were reported. Statistically significant intrusion (2.1 ± 0.9 mm was obtained during active treatment. Inserting miniscrews generally was presented with greater sulcus bleeding, plaque accumulation and plaque formation at follow-up visits. There was a statistically significant increase in PI, PPD and BOP indices. Furthermore, the results showed decrease in KG level and M.S to GL level. Conclusion: Miniscrews can provide a clinical benefit as an absolute anchorage device. However, keeping a good oral hygiene is essential to achieve ideal results, because the presence of miniscrews, as a foreign object in mouth, and intrusion force might be harmful for periodontal tissues

  6. Excess molar volumes and partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and p = 0.1 MPa

    International Nuclear Information System (INIS)

    Deenadayalu, N.; Bhujrajh, P.

    2006-01-01

    The excess molar volumes and the partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and at atmospheric pressure are reported. The hydrogen bonding between the OH133;NC groups are discussed in terms of the chain length of the alkanol. The alkanols studied are (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol). The excess molar volume data was fitted to the Redlich-Kister equation The partial molar volumes were calculated from the Redlich-Kister coefficients

  7. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  8. X-RAY MEASUREMENTS OF IMPACTED MANDIBULAR THIRD MOLARS

    Directory of Open Access Journals (Sweden)

    Petya G. Kanazirska

    2017-03-01

    Full Text Available The X-ray diagnostics is essential in case of retention of teeth. An important condition for proper treatment plan for impacted third molars of the mandible is the determination of the type of retention in the jaw in accordance with their medio-distal inclination and the space available for eruption (retromolar space. Purpose: The purpose of this article is to present an objective method for determination of the medio-distal inclination and the space for eruption of the third molars of the mandible. Materials and methods: The studied patients with impacted third molars of the mandible are 127, aged 17 through 60. They were examined with Cone-beam Computed Tomography (CBCT. On the orthopantomography, obtained after the scanning as a reconstructed image, we defined the medio-distal inclination and space for eruption of the third molars of the mandible. For this purpose, we summarized several methods. Results: The most common inclination of the third molars of the mandible with retained eruption is the medial one at 120 teeth (61.5% ± 3.5. Second in frequency is the vertical one-34 teeth (17.4% ± 2.7, followed by the distal inclination– 21 teeth (10.8% ± 2.2. With the lowest frequency are the teeth which are positioned horizontally –20 teeth (10.3% ± 2.2. Shortage of retromolar space is established for173 teeth (88.7% ± 2.3. In 22 teeth (11.3% ± 2.3 there is enough space in the jaw for eruption. Conclusion: An objective method for determination of the medio-distal inclination of the teeth and the space available for eruption is introduced for the first time in Bulgaria. By determining the inclination of impacted wisdom teeth under this methodology one can avoid the subjective factor–the seventh tooth. It is not a reference plane, because it can also be tilted or missing. With the help of the developed method the retromolar point can be determined more objectively.

  9. The molar hydrodynamic volume changes of factor VIIa due to GlycoPEGylation

    DEFF Research Database (Denmark)

    Plesner, Bitten; Westh, Peter; Hvidt, Søren

    2011-01-01

    The effects of GlycoPEGylation on the molar hydrodynamic volume of recombinant human rFVIIa were investigated using rFVIIa and two GlycoPEGylated recombinant human FVIIa derivatives, a linear 10 kDa PEG and a branched 40 kDa PEG, respectively. Molar hydrodynamic volumes were determined by capillary......, that the molar hydrodynamic volume of the conjugated protein is not just an addition of the molar hydrodynamic volume of the PEG and the protein. The molar hydrodynamic volume of the GlycoPEGylated protein is larger than the volume of its composites. These results suggest that both the linear and the branched...

  10. Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease

    International Nuclear Information System (INIS)

    McGinnis, J.P. Jr.; Hopkins, K.P.; Thompson, E.I.; Hustu, H.O.

    1987-01-01

    Sequential panoramic radiographs were assessed for mandibular third molar development in 47 long-term survivors of childhood Hodgkin's disease after treatment with 37 Gy mantle field radiation. To make a comparison, panoramic radiographs of 149 healthy, nonirradiated children were reviewed for the presence of mandibular third molars. In children between the ages of 7 and 12 years, bilateral agenesis of mandibular third molars was more frequent in patients who had been treated with mantle radiation than in nonirradiated patients. Unilateral agenesis, crown hypoplasia, and root growth impairment of mandibular third molars were also found. Similar, apparent, radiation-induced developmental anomalies were noted in maxillary third molars of the irradiated patients

  11. Prevalence of plaque and dental decay in the first permanent molar in a school population of south Mexico City.

    Science.gov (United States)

    Taboada-Aranza, Olga; Rodríguez-Nieto, Karen

    2018-01-01

    The first permanent molar is susceptible to acquire tooth decay since its eruption, due to its anatomy and because it has been exposed before other teeth. An observational, prolective, transversal and comparative study in 194 students, with an average age of 9.9 ± 1.8 years. The evaluation of the dentobacterial plate (DBP) was analyzed using the O'Leary index and the tooth decay experience with the DMFS (sum of decayed, missing, extracted and filling dental surfaces) and DMFT (sum of decayed, missing, extracted and filling per tooth) indexes. The prevalence of DBP in the first permanent molar was of 99.4% and tooth decay of 57.2%. The value of DMFT was 1.4 ± 1.4. The tooth decay experience was higher in children from 7.10 years old with a value of 2.2 ± 2.3, who are 7.9 times more likely to develop lesions than younger children (odds ratio: 8.9; 95% confidence interval: 4.1-19.5; p tooth decay experience indexes; even though these were weak in the case of DMF (r = 0.439), the model allowed to explain 19% of the association, and 22% for DMFT (r = 0.464). Tooth decay develops rapidly in the first permanent molars; however, it does not receive the necessary care because it is usually unknown that it is a permanent tooth. Copyright: © 2018 Permanyer.

  12. Assessment of age of majority by measurement of open apices of the third molars using Cameriere's third molar maturity index.

    Science.gov (United States)

    Sharma, Preeti; Wadhwan, Vijay; Ravi Prakash, S M; Aggarwal, Pooja; Sharma, Neeraj

    2017-01-01

    Evaluation of biological age of a living subject around the legal cutoff age for adulthood has become a grave concern for forensic experts in India, mainly due to the consequences of criminal obligations in judicial proceedings. Thus, this study was planned to examine the open apices of third molars in discriminating between individuals who are aged 18 years or older and who are not 18 years or older and to assign a cutoff for estimation of the age of 18 years. Orthopantomographs of 1062 individuals (14 and 23 years) were assessed, to verify Cameriere's third molar maturity index (I 3M ). The apical ends of the roots of the left mandibular third molar were analyzed. If the apical ends of the roots are completely closed, then I 3M is zero; otherwise, it is calculated as the sum of the distances between the inner sides of the two open apices divided by the tooth length. The sensitivity of the test for 0.08 value was 74.7% for males and 66% for females. Specificity was 83.6% for males and 79.6% for females. The probability that an Indian individual with an I 3M age in Indian population.

  13. On the Size Dependence of Molar and Specific Properties of Independent Nano-phases and Those in Contact with Other Phases

    Science.gov (United States)

    Kaptay, George

    2018-05-01

    Nano-materials are materials with at least one nano-phase. A nano-phase is a phase with at least one of its dimensions below 100 nm. It is shown here that nano-phases have at least 1% of their atoms along their surface layer. The ratio of surface atoms is proportional to the specific surface area of the phase, defined as the ratio of its surface area to its volume. Each specific/molar property has its bulk value and its surface value for the given phase, being always different, as the energetic states of the atoms in the bulk and in the surface layer of a phase are different. The average specific/molar property of a nano-phase is modeled here as a linear combination of the bulk and surface values of the same property, scaled with the ratio of the surface atoms. That makes the performance of all nano-phases proportional to their specific surface area. As the characteristic size of the nano-phase is inversely proportional to its specific surface area, all specific/molar properties of nano-phases are inversely proportional to the characteristic size of the phase. This is applied to the size dependence of the molar Gibbs energy of the nano-phase, which appears to be in agreement with the thermodynamics of Gibbs. This agreement proves the general validity of the present model on the size dependence of the specific/molar properties of independent nano-phases. It is shown that the properties of nano-phases are different for independent nano-phases (surrounded only by their equilibrium vapor phase) and for nano-phases in multi-phase situations, such as a liquid nano-droplet in the sessile drop configuration.

  14. Modified distal shoe appliance for the loss of a primary second molar: a case report.

    Science.gov (United States)

    Dhull, Kanika Singh; Bhojraj, Nandlal; Yadav, Shweta; Prabhakaran, Sheeja Devi

    2011-01-01

    Preservation of primary teeth until their normal exfoliation plays a crucial role in preventive and interceptive dentistry. Premature loss of the primary second molar prior to the eruption of the permanent first molar in the absence of the primary second molar can lead to mesial movement and migration of the permanent molar before and during its eruption. In such cases, an intra-alveolar type of space maintainer to guide the eruption of the permanent first molar is indicated. In certain cases, however, the conventional design is not practical. This paper describes a new design for distal shoe appliances in cases of primary second molar loss prior to the eruption of the permanent mandibular first molar.

  15. Exodoncia del tercer molar: Factores que determinan complejidad

    Directory of Open Access Journals (Sweden)

    Ivan Manotas Arevalo

    2014-06-01

    Full Text Available ResumenUno de los procedimientos más frecuentes en el campo de la Cirugía Oral es la exodoncia, o extracción dental. La prevención y la promoción de hábitos saludables dentro de los que se cuenta la práctica del cepillado dental, uso de dentífricos, hilo dental y enjuagatorios bucales, además de visitas periódicas de control a especialistas y odontólogos generales e higienistas bucales ha conllevado a una reducción en la perdida de estructuras dentarias por causa de la caries y las periodontopatìas. Sin embargo se mantiene alto el número de exodoncias indicadas por falta de espacio en la estructura de los maxilares para la erupción dental, así como alteraciones en la posición y angulacion de los órganos dentales sobre su eje que impide una adecuada ubicación logrando que se indique su extracción. Dentro de la serie dental los órganos dentarios más frecuentemente afectados por este tipo de alteraciones son los terceros molares. También se mencionan que son esos mismos dientes los que acusan mayor grado de complejidad para realizar el procedimiento de exodoncia, y los que causan mayor grado de morbilidad posquirúrgica en el paciente, con un número mayor de complicaciones y su severidad, descritas en la literatura. (Duazary 2008; 141-147. Este artículo pretende analizar los factores que determinan complejidad en la exodoncia del tercer molar a partir de una revisión bibliografía y comparación de ésta.AbstractOne of the most frequent procedure used in the field of Oral Surgery is extracted, or tooth extraction. The prevention and promoting healthy habits in mind that the practice of brushing teeth, use of toothpastes, mouthwashes and dental floss mouth, in addition to regular monitoring visits to specialists and general dentists and oral hygiene has led to a reduction in the loss of structures caused by tooth decay and periodontal pathology. However remains high number of extractions indicated by lack of space in the

  16. [Molar incisor hypomineralization (MIH)--a literature review].

    Science.gov (United States)

    Gotler, M; Ratson, T

    2010-04-01

    MIH was defined by Weerheijm (2001) as "hypomineralisation of systemic origin of 1-4 permanent first molars, frequently associated with affected incisors". The prevalence of MIH varies between 2.8% and 25%, dependent upon the study. At their sixth congress in 2003, The European Association of pediatric dentistry defined criteria for diagnosis of the phenomena. It included the presence of demarcated opacity, posteruptive enamel breakdown, atypical restoration, extracted molar due to MIH and unerupted teeth. According to the teeth involved and to the time of the crown formation, researches focused on environmental and systemic conditions as possible reasons for MIH.The etiologies were divided into five groups: Exposure to environmental contaminants, pre/peri and neonatal problems, exposure to fluoride, common childhood illnesses and medically compromised children. The clinical implications include highly sensitive teeth, difficulty to achieve adequate anesthesia, behavioral problems and anxiety, rapid progression of caries and the esthetic implications. A six step approach to management was described suggested: risk identification, early diagnosis, remineralization and desensitization, prevention of caries and posteruption breakdown, restorations and extractions and finally maintenance. Restoring an affected molar can vary from adhesive intra coronal restorations (resin composite is the material of choice) to extra coronal restorations (e.g. preformed metal crown). Esthetic solutions to affected incisors may include microabrasion (that shows little improvement) and resin composite or porcelain veneer. The key for a successful treatment is early diagnosis, intense follow up and usage of remineralizating agents as soon as the teeth erupt. There is still need for further research to clarify the etiological factors and improve the durability of restoration in affected teeth.

  17. Incidence of cystic changes in impacted lower third molar

    Directory of Open Access Journals (Sweden)

    Shridevi R Adaki

    2013-01-01

    Full Text Available Objective: To assess the incidence of cystic changes in the impacted lower third molar (ILTM in which the pericoronal (follicular space is less than 2.5 mm as measured from the radiograph. The relationship between the cystic changes and patient′s age, sex, and angular position and contact of ILTM with adjacent tooth was also evaluated. Materials and Methods: Follicular space less than 2.5 mm as measured from the panoramic radiograph was included in the study. A total of 73 tissue samples collected during the extraction ILTM were examined histopathologically. Then the data were analyzed for associations with age, sex, angular position, and contact of the ILTM with an adjacent tooth. Results: There were 37 male and 36 female patients, age ranging from 17 to 35 years (mean 23.95 years. Out of 73 specimens, 17 (23.3% showed cystic changes; among them 16 (22.1% showed dentigerous cysts and 1 (1.2% showed odontogenic keratocysts. Most of the cystic changes occurred in the 26-30 year age range. The cystic changes showed male predominance but could not gain statistical significance. The relationship between cystic changes and angular position was statistically significant (P < 0.05. Higher probability was found in distoangular positioned ILTM. The relationship between cystic changes and communication of ILTM with the second molar was not statistically significant. Conclusion: Incidence of cystic changes in ILTM justifies extraction of the impacted tooth associated with symptoms. The decision to extract or not to extract impacted third molar should be individualized, rather than generalized.

  18. Cameriere's third molar maturity index in assessing age of majority.

    Science.gov (United States)

    Galić, Ivan; Lauc, Tomislav; Brkić, Hrvoje; Vodanović, Marin; Galić, Elizabeta; Biazevic, Maria Gabriela Haye; Brakus, Ivan; Badrov, Jozo; Cameriere, Roberto

    2015-07-01

    Estimation of chronological age of an individual is one of the main challenges in forensic science. Legally to be able to treat a person as a minor or an adult, it is necessary to determine whether their age of majority (if they are older or younger than 18, in most countries). Methods for estimating age are especially important when an individual in question lacks personal documents or other means of identification. As the dental age differs in various populations, the aim of this study was to evaluate applicability of third molar method for assessing age of majority in Croatia. Cameriere's third molar maturity index (I3M) value of 0.08, measured by the open apices of the teeth, was verified in sample of 1336 panoramic images aged between 14 and 23 years. Chronological age gradually decreased as I3M increased in both genders. Males showed statistically significant advanced maturation when I3M was between 0.0 and 0.3 value. The results indicate that the sensitivity of the test for 0.08 value was 84.3% (95%CI 80.6%, 87.5%) for females and 91.2% (95%CI 88.7%, 93.1) for males. Specificity was 95.4% (95%CI 92.5%, 97.5%) and 91.9% (95%CI 88.8%, 94.3%). The proportions of accurately classified males were 88.8% and that of females 91.5%. The estimated post-test probabilities, of individuals, in other word the probability that a Croatian individual with an I3Mthird molar maturity index should be used as a determinant of the age of majority in Croatia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. VVER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (author)

  20. WWER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (Authors)

  1. La cirugía periapical de los molares

    OpenAIRE

    Gay Escoda, Cosme; Paredes García, Jordi; Berini Aytés, Leonardo

    1993-01-01

    Se han estudiado 65 pacientes sometidos a intervención quirúrgica periapical en 72 molares ( 120 raíces y 155 conductos radiculares). Se analizó una serie de características preoperatorias (edad, antecedentes patológicos, patologías asociadas, distribución de dientes afectados, tamaño de la lesión periapical, tipo de endodoncia ortógrafa y calidad radiológica de la endodoncia previa), peroperatorias (tipo de incisión, existencia de comunicación oroantral, afectación cortical, tamaño de la res...

  2. Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns

    Directory of Open Access Journals (Sweden)

    Roopak Bose Carlos

    2013-01-01

    Full Text Available Clinical success of endodontically treated posterior teeth is determined by the postendodontic restoration. Several options have been proposed to restore endodontically treated teeth. Endocrowns represent a conservative and esthetic restorative alternative to full coverage crowns. The preparation consists of a circular equigingival butt-joint margin and central retention cavity into the entire pulp chamber constructing both the crown and the core as a single unit. The case reports discussed here are moderately damaged endodontically treated molars restored using all ceramic endocrowns fabricated using two different systems, namely, CAD/CAM and pressed ceramic.

  3. Irregular Periapical Radiopacity in Mandibular Premolars and Molars

    Directory of Open Access Journals (Sweden)

    S. Aravind Warrier

    2014-01-01

    Full Text Available Increased deposition of cementum is observed in a wide number of both benign and malignant conditions. Many cases are often diagnosed during routine examination as an incidental finding. Diagnosing correctly without confusing it with other similarly appearing lesions, thus avoiding subjecting the patient to unnecessary investigations and stress, is of prime importance. We report one such case, where the patient presented with the routine complaint of a painful tooth, during the investigation of which he was also diagnosed with hypercementosis affecting the mandibular second premolars and molars bilaterally. The literature review reveals that not many cases of hypercementosis are frequently reported.

  4. Cervical and mediastinal emphysema secondary to third molar extraction.

    Science.gov (United States)

    Goodnight, J W; Sercarz, J A; Wang, M B

    1994-01-01

    A dramatic case of infected emphysema involving multiple deep cervical and mediastinal fascial planes following surgical extraction of a lower third molar in an otherwise healthy man is presented. The differential diagnosis and management of this condition are discussed, specifically contrasting it to necrotizing fasciitis. The direct cause of this complication was the use of an air turbine handpiece and air syringe for the tooth extraction. It is advised that air turbine handpieces and air syringes not be used during minor oral surgical procedures.

  5. Mini-implants: mechanical resource for molars uprighting

    Directory of Open Access Journals (Sweden)

    Susiane Allgayer

    2013-02-01

    Full Text Available INTRODUCTION: The early orthodontic treatment allows correction of skeletal discrepancies by growth control, and the elimination of deleterious habits, which are risk factors for the development of malocclusions, favoring for the correction of tooth positioning later in a second treatment stage. During development of teeth and occlusion, the mandibular second molars commonly erupt in the oral cavity after all other teeth of the anterior region. In their eruptive process there may be a condition known as tooth impaction, which precludes its complete eruption and requires proper uprighting treatment. The temporary anchorage devices allow disimpaction and movement of these teeth directly to their final position, without the need of patient compliance or reaction movements in other parts of the arch. OBJECTIVE: This paper aims at describing a case report of the treatment of a patient with Angle Class II malocclusion, performed in two phases, in which mini-implants were used for uprighting the impacted mandibular second molars.INTRODUÇÃO: o tratamento ortodôntico precoce permite a correção das discrepâncias esqueléticas por meio do controle de crescimento e a eliminação de hábitos deletérios, que são fatores de risco para o desenvolvimento de más oclusões, que favorecem a correção do posicionamento dentário mais tardiamente, em uma segunda fase do tratamento. Durante o desenvolvimento da dentição e da oclusão, normalmente o segundo molar inferior chega à cavidade bucal após todos os dentes posicionados anteriormente a ele. Durante seu processo eruptivo, pode ocorrer uma condição chamada "impacção dentária", em que sua erupção completa é interrompida, exigindo tratamento apropriado para verticalização. Os dispositivos temporários de ancoragem permitem a desimpacção e a movimentação desses dentes diretamente às suas posições finais, sem a necessidade de cooperação do paciente e sem movimento de reação nas

  6. Human age estimation combining third molar and skeletal development.

    Science.gov (United States)

    Thevissen, P W; Kaur, J; Willems, G

    2012-03-01

    The wide prediction intervals obtained with age estimation methods based on third molar development could be reduced by combining these dental observations with age-related skeletal information. Therefore, on cephalometric radiographs, the most accurate age-estimating skeletal variable and related registration method were searched and added to a regression model, with age as response and third molar stages as explanatory variable. In a pilot set up on a dataset of 496 (283 M; 213 F) cephalometric radiographs, the techniques of Baccetti et al. (2005) (BA), Seedat et al. (2005) (SE), Caldas et al. (2007) and Rai et al. (2008) (RA) were verified. In the main study, data from 460 (208 F, 224 M) individuals in an age range between 3 and 26 years, for which at the same day an orthopantogram and a cephalogram were taken, were collected. On the orthopantomograms, the left third molar development was registered using the scoring system described by Gleiser and Hunt (1955) and modified by Köhler (1994) (GH). On the cephalograms, cervical vertebrae development was registered according to the BA and SE techniques. A regression model, with age as response and the GH scores as explanatory variable, was fitted to the data. Next, information of BA, SE and BA + SE was, respectively, added to this model. From all obtained models, the determination coefficients and the root mean squared errors were calculated. Inclusion of information from cephalograms based on the BA, as well as the SE, technique improved the amount of explained variance in age acquired from panoramic radiographs using the GH technique with 48%. Inclusion of cephalometric BA + SE information marginally improved the previous result (+1%). The RMSE decreased with 1.93, 1.85 and 2.03 years by adding, respectively, BA, SE and BA + SE information to the GH model. The SE technique allows clinically the fastest and easiest registration of the degree of development of the cervical vertebrae. Therefore, the choice of

  7. Anesthetic management in thyroid crisis triggered by molar pregnancy

    Directory of Open Access Journals (Sweden)

    Harun Aydoğan

    2012-09-01

    Full Text Available Clinical thyrotoxicosis is one of the rare complications of molar pregnancy. The cause of the symptoms associated with hyperthyroidism in mol hydatiform is the thyrotrophic effects of high levels of β-hCG. The hCG molecule consists of α and β subunits; the α subunit is identical to TSH and the β subunit has a similar structure to TSH. In this case report it was aimed to discuss the anesthetic management of a dilatation and curettage case in a patient with mol hydatiform and thyroid crisis. J Clin Exp Invest 2012; 3 (3: 433-434Key words: Hydatidiform mole, hyperthyroidism, anesthesia

  8. Sharpening Sharpe Ratios

    OpenAIRE

    William N. Goetzmann; Jonathan E. Ingersoll Jr.; Matthew I. Spiegel; Ivo Welch

    2002-01-01

    It is now well known that the Sharpe ratio and other related reward-to-risk measures may be manipulated with option-like strategies. In this paper we derive the general conditions for achieving the maximum expected Sharpe ratio. We derive static rules for achieving the maximum Sharpe ratio with two or more options, as well as a continuum of derivative contracts. The optimal strategy has a truncated right tail and a fat left tail. We also derive dynamic rules for increasing the Sharpe ratio. O...

  9. Radiographic evaluation of third molar development in 6 to 24 year olds

    International Nuclear Information System (INIS)

    Jung, Yun Hwa; Cho, Bong Hae

    2014-01-01

    This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females.

  10. Radiographic evaluation of third molar development in 6- to 24-year-olds

    Science.gov (United States)

    Jung, Yun-Hoa

    2014-01-01

    Purpose This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females. PMID:25279338

  11. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1985-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs

  12. Detecting isotopic ratio outliers

    Science.gov (United States)

    Bayne, C. K.; Smith, D. H.

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers.

  13. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1986-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers

  14. Bacterial intensity and localization in primary molars with caries disease

    Directory of Open Access Journals (Sweden)

    A P Beltrame

    2012-01-01

    Full Text Available Aim: The aim was to assess the characteristics and outcomes of infections affecting the structures of carious primary molars. Materials and Methods: Forty primary molars were used and classified according to the following clinical situation: With profound caries lesion, with bone loss at the furcation region, with perforation of the pulp chamber floor, and residual roots. The teeth were demineralized, cut, and stained with both haematoxylin-eosin and Brown and Brenn staining techniques. Assessment was performed using optical microscopy. Results: Statistical analysis of the data by means of the Chi-square test suggests that there was a significant relationship (P<0.001 between the intensity and localization of infection and the level of destruction of dental structures. A significant difference was also observed in the intensity and localization of infection between the groups regarding crown, furca, and root (P<0.001. Conclusion: More intense and profound the infection, more severe is the dental destruction. The groups of residual roots showed the most severe bacterial infection compared to other groups.

  15. Assessment of skeletal maturation using mandibular second molar maturation stages.

    Science.gov (United States)

    Goyal, S; Goyal, S; Gugnani, N

    2014-01-01

    To investigate the relationship between cervical vertebrae maturation and mandibular second molar calcification stages. The study was designed as a retrospective, descriptive and crosssectional research project. Pre-treatment lateral cephalograms and panoramic radiographs of 99 males and 110 females in the age range of 7 to 18 years 7 months were evaluated with Demirjian Index (DI) and cervical vertebrae maturation indicators (CVMI) of Hassel and Farman. A null hypothesis was proposed that there is no relation between CVMI and DI. A highly significant association (Pearson's contingency coefficient 0.713 for males and 0.863 for females) was found between DI and CVMI. In males, the DI stage E corresponded to stage 2 of CVMI (pre-peak of pubertal growth spurt) and DI stages F and G corresponded to stages 3 and 4 of CVMI (peak of pubertal growth spurt). DI stage H was associated with stages 5 and 6 of CVMI (end of pubertal growth spurt). In females, the DI stages C, D corresponded to CVMI stages 1, 2; DI stages E, F with CVMI stages 3, 4; DI stages G, H with CVMI stages 5, 6. Mandibular second molar calcification stages can be used as indicators for assessment of skeletal maturity.

  16. Ovariectomy delays alveolar wound healing after molar extractions in rats.

    Science.gov (United States)

    Pereira, Michele Conceição; Zecchin, Karina Gottardello; Campagnoli, Eduardo Bauml; Jorge, Jacks

    2007-11-01

    This study was conducted to investigate the morphological effects of the absence of estrogen on alveolar wound healing of young female rats after tooth extraction. A total of 60 4- to 6-week-old female rats underwent bilateral ovariectomy (OVX) or sham operations. Three weeks later, the first mandibular molars were extracted. Subsequently, the animals were killed by cervical dislocation 3, 5, 7, 14, 21, or 28 days after tooth extraction. The mandibles were removed, and serial transversal sections of mesial alveolus of the first mandibular molars were obtained for histometric analysis. OVX sockets showed significant increases in fibroblasts and collagen content 3 and 5 days after the extractions, followed by significant decreases in these parameters in the subsequent periods. In accordance with the decreased collagen content in the latest period of healing, new bone formation was significantly reduced in the OVX animals. These findings suggest that the initial molecular changes observed in the absence of estrogen lead to delayed alveolar wound healing.

  17. Differential Expression of p63 in Hydropic and Molar Gestations

    International Nuclear Information System (INIS)

    Masood, S.; Kehar, S. I.; Shawana, S.; Aamir, I.

    2015-01-01

    Objective:To observe the differential expression of p63 in hydropic and molar gestation. Study Design: Cross-sectional analytical study. Place and Duration of Study: Department of Pathology, Basic Medical Sciences Institute, Jinnah Postgraduate and Medical Centre, Karachi, from January 2006 to June 2013. Methodology: Ninety placental biopsies including 30 cases each of hydropic abortions, partial hydatidiform mole and complete hydatidiform mole were analyzed for morphological features and results of immunohistochemical staining. Results were described as frequency. Significance was determined using test of proportions with significance at p < 0.05. Results: Out of 30 cases of hydropic abortion, 6 were negative, 15 were weak, 4 were moderate and 5 showed strong degree of intensity for p63. Out of 30 cases of partial hydatidiform mole, 3 were negative, 2 showed weak, 4 showed moderate and 21 cases showed strong degree of intensity for p63. All 30 cases of complete hydatidiform mole strongly stained for p63. Conclusion: The intensity of staining of p63 was stronger in cases of molar pregnancy as compared to hydropic abortion. There was loss of p63 expression in cytotrophoblastic cells in all abortions. In limited resources settings, where facilities for PCR/FISH and DNA ploidy analysis is not available, the authors advocate p63 in routine clinical practice to provide the most refined diagnosis of hydatidiform moles. (author)

  18. Infinitely dilute partial molar properties of proteins from computer simulation.

    Science.gov (United States)

    Ploetz, Elizabeth A; Smith, Paul E

    2014-11-13

    A detailed understanding of temperature and pressure effects on an infinitely dilute protein's conformational equilibrium requires knowledge of the corresponding infinitely dilute partial molar properties. Established molecular dynamics methodologies generally have not provided a way to calculate these properties without either a loss of thermodynamic rigor, the introduction of nonunique parameters, or a loss of information about which solute conformations specifically contributed to the output values. Here we implement a simple method that is thermodynamically rigorous and possesses none of the above disadvantages, and we report on the method's feasibility and computational demands. We calculate infinitely dilute partial molar properties for two proteins and attempt to distinguish the thermodynamic differences between a native and a denatured conformation of a designed miniprotein. We conclude that simple ensemble average properties can be calculated with very reasonable amounts of computational power. In contrast, properties corresponding to fluctuating quantities are computationally demanding to calculate precisely, although they can be obtained more easily by following the temperature and/or pressure dependence of the corresponding ensemble averages.

  19. Supplemental root in a mandibular first molar: a rarity

    Directory of Open Access Journals (Sweden)

    Poonam Mahajan

    2011-04-01

    Full Text Available Anatomic variations are common in human dentition. A clear understanding of these variations is very important for success of endodontic treatment. A dentist should be aware of these anatomic variations as this can affect the treatment outcome. A case of endodontic therapy is presented in which inability to locate an anatomically rare supplemental canal of a three rooted mandibular first molar resulted in treatment failure. A 21-year-old female reported with pain and swelling in relation to lower right first molar. An intra oral periapical radiograph revealed 3 roots; the first canal of the mesial root and a canal of one of the distal roots were found to be treated endodontically, which were infraobturated but the canal of the 2nd distal root had not been treated. The radiograph revealed periapical radiolucency and widening of periodontal space. Prior to starting the endodontic treatment the clinician must be aware of the anatomic variations in tooth pulp morphology and also the importance of preoperative radiographs cannot be underscored.

  20. Radiolucency below the crown of mandibular horizontal incompletely impacted third molars and acute inflammation in men with diabetes

    Directory of Open Access Journals (Sweden)

    Minoru Yamaoka

    2009-05-01

    Full Text Available Minoru Yamaoka, Yusuke Ono, Masahide Ishizuka, Kouichi Yasuda, Takashi Uematsu, Kiyofumi FurusawaOral and Maxillofacial Surgery, Matsumoto Dental University, Shiojiri, Nagano 399-0781, JapanAbstract: Although mandibular third molar has a high risk of infection extending any complications, the influence of diabetes on radiolucency and acute inflammation in pericoronitis remains unclear. The present study was to evaluate whether radiolucency below the crown is related to acute inflammation in mandibular horizontal incompletely impacted third molars and to review the records of 140 men more than 45 years with and without diabetes. The odds ratio of exhibiting acute inflammation was 3.38 (95% CI: 1.13–10.16, p < 0.05 and that of exhibiting severe acute inflammation was 15.38 (95% CI: 3.56–66.49, p < 0.0001, indicating an association of acute pericoronitis in diabetes. The frequency of radiolucency below the crown and below the root in diabetics was similar to that in nondiabetics. However, the odds ratio of exhibiting both radiolucency below the crown and acute inflammation under the diabetic condition was 4.85 (95% CI: 1.60–14.73, p < 0.01, whereas that of diabetics showing both radiolucency below the root and acute inflammation was 0.46 (95% CI: 0.06–3.74, p = 0.74. Radiolucency below the crown and acute inflammation were associated with diabetes, but that below root and acute inflammation were not associated with diabetes, indicating that the region below the crown carries susceptibility to acute pericoronitis, whereas the periodontium shows a protective effect against acute pericoronitis.Keywords: radiolucency, acute inflammation, mandible, third molar, diabetes, periodontium

  1. [Application of hand-use ProTaper instruments in endodontic treatment of molar canals].

    Science.gov (United States)

    Ma, Sui-qi; Xie, Qian; Zhou, Yin-feng

    2010-07-01

    To evaluate the application of hand-use ProTaper instruments in endodontic treatment of molar canals. A total of 203 permanent molars were randomly divided into the experimental group (99 molars) and control group (104 molars) prepared by hand-use ProTaper instruments and standard stainless steel K-file, respectively. The molars in the two groups were obturated by cold lateral condensation technique. The root canal preparation and obturation were evaluated by radiograph, and the working time of preparation and post-operative emergencies were analyzed. The preparation time in the experimental group was obviously shorter than that in the control group (Phand-use ProTaper instruments may improve the effect of root canal treatment of the molars and shorten the working time and reduce the post-operative emergencies.

  2. A rare case of retained fourth molar teeth in maxilla and mandible. Case report

    Directory of Open Access Journals (Sweden)

    Rahnama Mansur

    2014-06-01

    Full Text Available The study presents a case of the rarely occurring totally retained fourth molar teeth simultaneously in maxilla and mandible. The appearance of supernumerary teeth is a relatively uncommon dental anomaly and it is rare for patients to have impacted fourth molars in two quadrant. The aim of this work is to describe the presence of unilateral (right fourth molars in the maxilla and the mandible in a young female patient aged 24 years. Orthopantomogram revealed impacted lower third molars but also unerupted unilateral (right upper and lower fourth molars. Before orthodontic treatment, the patient was subsequently admitted for removal of third and fourth impacted upper and lower molars under local anesthesia.

  3. PAH diagnostic ratios for the identification of pollution emission sources

    International Nuclear Information System (INIS)

    Tobiszewski, Marek; Namieśnik, Jacek

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) diagnostic ratios have recently come into common use as a tool for identifying and assessing pollution emission sources. Some diagnostic ratios are based on parent PAHs, others on the proportions of alkyl-substituted to non-substituted molecules. The ratios are applicable to PAHs determined in different environmental media: air (gas + particle phase), water, sediment, soil, as well as biomonitor organisms such as leaves or coniferous needles, and mussels. These ratios distinguish PAH pollution originating from petroleum products, petroleum combustion and biomass or coal burning. The compounds involved in each ratio have the same molar mass, so it is assumed they have similar physicochemical properties. Numerous studies show that diagnostic ratios change in value to different extents during phase transfers and environmental degradation. The paper reviews applications of diagnostic ratios, comments on their use and specifies their limitations. - Highlights: ► PAH diagnostic ratios may identify pollution coming from petroleum spills, fuel combustion and coal or biomass burning. ► They are sensitive to changes during PAHs environmental fate processes. ► Some diagnostic ratios are of limited value due to fast photodegradation of one of the compounds. - The paper reviews PAH diagnostic ratios that are applied to identify pollution emission originating from petroleum products, fuel combustion or coal and biomass burning.

  4. Comparison of Articaine and Lidocaine for Buccal Infiltration After Inferior Alveolar Nerve Block For Intraoperative Pain Control During Impacted Mandibular Third Molar Surgery.

    Science.gov (United States)

    da Silva-Junior, Geraldo Prisco; de Almeida Souza, Liane Maciel; Groppo, Francisco Carlos

    In order to compare the efficacy of lidocaine and articaine for pain control during third molar surgery, 160 patients presenting bilateral asymptomatic impacted mandibular third molars were selected. They received 1.8 mL of 2% lidocaine with epinephrine 1:100,000 during inferior alveolar nerve block. In group 1 (n = 80), an infiltrative injection of 0.9 mL of 2% lidocaine with epinephrine 1:100,000 was performed in buccal-distal mucosa of the third molar. Group 2 (n = 80) received 0.9 mL of 4% articaine with epinephrine 1:100,000 in the contralateral side. All procedures were performed at the same visit, by a single operator, in a double-blind and parallel design. The duration of each surgery and the moment when the patient expressed pain were noted. Data were analyzed by nonpaired t test and chi-square test (alpha = 5%). Duration of surgery did not differ (p = .83) between Groups 1 (19.8 ± 2.3 minutes) and 2 (19.7 ± 3.0 minutes). Pain was expressed more in group 1 (26.3%) than in group 2 (10%) (odds ratio = 3.2, p = .0138). In both groups, tooth sectioning was the most painful event (p inferior alveolar nerve block in controlling intraoperative pain related to impacted mandibular third molar surgery.

  5. Management of Unilaterally Impacted Permanent Mandibular First, Second and Third Molars

    Directory of Open Access Journals (Sweden)

    Rohit Mehrotra

    2014-01-01

    Full Text Available This case report describes the treatment of a teenage patient with simultaneous impaction of all three right mandibular permanent molars. The impacted first and second mandibular molars were surgically exposed and orthodontically erupted into good alignment and occlusion while the impacted third molar in the same quadrant was extracted. The unique clinical presentation, various treatment alternatives, the decision making process in finalizing the treatment plan and its clinical implementation are discussed.

  6. Fate of third molar in line of mandibular angle fracture - Retrospective study

    Directory of Open Access Journals (Sweden)

    Preetha Balaji

    2015-01-01

    Conclusion: The present study fails to identify any concrete factors that would predict the failure of the retained third molar that were involved in the line of mandibular fractures. The proof presented here, especially with low complication rates indicate that all impacted third molar along the line of fracture be removed and unless necessary, the partially erupted teeth would also be extracted. In such a situation, the rate of infection and survival of the third molar would have been entirely different.

  7. Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation

    OpenAIRE

    Rodrigues, Clarissa Teles; de Oliveira-Santos, Christiano; Bernardineli, Norberti; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; Minotti-Bonfante, Paloma Gagliardi; Ordinola-Zapata, Ronald

    2016-01-01

    ABSTRACT The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present. Objectives: To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT. Material and Methods: CBCT images of 116 patien...

  8. Independent and Confluent Middle Mesial Root Canals in Mandibular First Molars: A Report of Four Cases

    Directory of Open Access Journals (Sweden)

    Mohanavelu Deepalakshmi

    2012-01-01

    Full Text Available Mandibular molars demonstrate considerable variations with respect to number of roots and root canals. The possibility of additional root canals should be considered even in teeth with a low frequency of abnormal root canal anatomy. This paper discusses the endodontic management of the rare anatomical complexity middle mesial canals in mandibular first molar and also serves to remind the clinicians that such anatomical variations should be taken into account during the endodontic treatment of the mandibular molars.

  9. The partial molar volume of BeSO4 in aqueous solutions

    International Nuclear Information System (INIS)

    Kuschel, F.; Seidel, J.

    1981-01-01

    The density of aqueous solutions of BeSO 4 has been measured as a function of the mole fraction in the range of 0.02487 x 10 -2 to 6.3082 x 10 -2 . From the results obtained the molar volume and partial molar volume have been calculated and the limiting value of the partial molar volume for Be 2+ was extrapolated in accordance with the Debye-Hueckel law

  10. Prevalence of missing and impacted third molars in adults aged 25 years and above

    OpenAIRE

    Jung, Yun-Hoa; Cho, Bong-Hae

    2013-01-01

    Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent ...

  11. Age estimation using development of third molars in South Indian population: A radiological study.

    Science.gov (United States)

    Priyadharshini, K Indra; Idiculla, Jose Joy; Sivapathasundaram, B; Mohanbabu, V; Augustine, Dominic; Patil, Shankargouda

    2015-05-01

    To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A-H) method of Demirjian et al. in Chennai population of South India. A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization.

  12. Molar volume dependence of the pressure of solid 3He at very low temperatures

    International Nuclear Information System (INIS)

    Mamiya, T.; Sawada, A.; Fukuyama, H.; Iwahashi, K.; Masuda, Y.

    1983-01-01

    The pressure of solid 3 He has been measured as a function of temperature T between 0.3 and 50 mK at molar volumes between 24.19 and 23.31 cm 3 . The entropy discontinuity obtained from the pressure jump at the ordering transition turned out to be almost independent of molar volumes, being about 0.40Rln2 in the studied range of molar volumes

  13. Endodontic Management of Maxillary Second Molar with Two Palatal Roots: A Report of Two Cases

    OpenAIRE

    Patel, Surbhi; Patel, Pawan

    2012-01-01

    Endodontic treatment may sometimes fail because morphological features of the tooth adversely affect the treatment protocol. Maxillary second molars are recognized as usually having a single palatal root with a single palatal canal. The incidence of second palatal root in the maxillary second molar is very rare. Two cases are presented in this paper describing the endodontic management of a four-rooted maxillary second molar with two distinct palatal roots and canals and two distinct buccal r...

  14. Modified Distal Shoe Appliance for Premature Loss of Multiple Deciduous Molars: A Case Report

    OpenAIRE

    Bhat, Prasanna Kumar; K., Navin H.; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

    2014-01-01

    Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist’s armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first...

  15. Treatment of ectopically erupting maxillary permanent first molars with a distal extended stainless steel crown.

    Science.gov (United States)

    Roberts, M W

    1986-01-01

    The exaggerated mesial eruption of the permanent first molar can result in the tooth becoming impacted, or the premature atypical resorption and exfoliation of the primary molar, with a resultant loss of space. A stainless steel crown with a distal guide plane was placed on a primary molar to correct the aberrant eruption angle of the permanent tooth. This procedure can be used successfully for both partially and totally tissue-impacted teeth, and is described in this report.

  16. DNAJB6 is a peptide-binding chaperone which can suppress amyloid fibrillation of polyglutamine peptides at substoichiometric molar ratios

    NARCIS (Netherlands)

    Mansson, Cecilia; Kakkar, Vaishali; Monsellier, Elodie; Sourigues, Yannick; Harmark, Johan; Kampinga, Harm H.; Melki, Ronald; Emanuelsson, Cecilia

    Expanded polyglutamine (polyQ) stretches lead to protein aggregation and severe neurodegenerative diseases. A highly efficient suppressor of polyQ aggregation was identified, the DNAJB6, when molecular chaperones from the HSPH, HSPA, and DNAJ families were screened for huntingtin exon 1 aggregation

  17. The molar H: Corg ratio of biochar is a key factor in mitigating N2O emissions from soil

    NARCIS (Netherlands)

    Cayuela, M.L.; Jeffery, S.L.; Zwieten, van L.

    2015-01-01

    A previously published meta-analysis of biochar impacts on soil N2O emissions by Cayuela et al. (2014) found a “grand mean” reduction in N2O emissions of 54 ± 6% following biochar application to soil. Here we update this analysis to include 26 additional manuscripts bringing the total to 56

  18. The unfolding effects on the protein hydration shell and partial molar volume: a computational study.

    Science.gov (United States)

    Del Galdo, Sara; Amadei, Andrea

    2016-10-12

    In this paper we apply the computational analysis recently proposed by our group to characterize the solvation properties of a native protein in aqueous solution, and to four model aqueous solutions of globular proteins in their unfolded states thus characterizing the protein unfolded state hydration shell and quantitatively evaluating the protein unfolded state partial molar volumes. Moreover, by using both the native and unfolded protein partial molar volumes, we obtain the corresponding variations (unfolding partial molar volumes) to be compared with the available experimental estimates. We also reconstruct the temperature and pressure dependence of the unfolding partial molar volume of Myoglobin dissecting the structural and hydration effects involved in the process.

  19. Periodontal considerations in the use of bonds or bands on molars in adolescents and adults.

    Science.gov (United States)

    Boyd, R L; Baumrind, S

    1992-01-01

    This longitudinal study compared the periodontal status of bonded and banded molars in 20 adult and 40 adolescent patients before, during and after treatment with fixed orthodontic appliances. Plaque accumulation (measured by the Plaque Index), gingival inflammation (measured by the Gingival Index and the bleeding tendency), and pocket depth were assessed by one examiner at sites along the mesio-buccal line angle of the maxillary right first molar and the mandibular left first molar. Assessments were made immediately prior to the placement of fixed appliances (pretreatment), at 1, 3, 6, 9, 12 and 18 months after appliances were placed; and 3 months after appliances were removed (posttreatment). Loss of attachment between the pretreatment and posttreatment visits also was determined. At pretreatment, no significant differences were found in gingival inflammation between maxillary and mandibular banded and bonded molars. During treatment, both maxillary and mandibular banded molars showed significantly (p less than 0.05) greater gingival inflammation and plaque accumulation than did bonded molars. Three months after appliance removal, the maxillary molars that had been banded continued to show significantly more gingival inflammation and loss of attachment than did the maxillary molars that had been bonded. When all banded and bonded teeth were grouped by patient age, mean values for plaque accumulation and gingival inflammation in the maxillary molar regions were significantly greater for adolescents than for adults.

  20. Immediate Placement of Ultrawide-Diameter Implants in Molar Sockets: Description of a Recommended Technique.

    Science.gov (United States)

    Hattingh, André C; De Bruyn, Hugo; Ackermann, Andrew; Vandeweghe, Stefan

    Immediate implant placement is performed less frequently in molar extraction sockets than in single root sockets. This is mainly due to the tripodal anatomical configuration of molar roots, which is perceived as complex and therefore unsuitable. The mechanical burden of molar sites, combined with much larger socket dimensions, make it amenable to the use of ultrawide-diameter dental implants. This article describes a practical, sequenced technique that can be used predictably for immediate implant placement in maxillary and mandibular first molar sockets, using a dry skull model for clarification. This detailed description is based on the experience of more than 580 clinical cases over a 10-year period.

  1. Molar Volume Analysis of Molten Ni-Al-Co Alloy by Measuring the Density

    Institute of Scientific and Technical Information of China (English)

    XIAO Feng; FANG Liang; FU Yuechao; YANG Lingchuan

    2004-01-01

    The density of molten Ni-Al-Co alloys was measured in the temperature range of 1714~1873K using a modified pycnometric method, and the molar volume of molten alloys was analyzed. The density of molten Ni-Al-Co alloys was found to decrease with increasing temperature and Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys increases with increasing Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys shows a negative deviation from the linear molar volume.

  2. CT analyses of the location of the maxillary third molar in relation to panoramic radiographic appearance

    International Nuclear Information System (INIS)

    Obayashi, Naofumi; Ariji, Yoshiko; Goto, Masakazu; Izumi, Masahiro; Naitoh, Munetaka; Kurita, Kenichi; Shimozato, Kazuo; Ariji, Eiichiro

    2009-01-01

    We compared the relationship between anatomical structures analyzed by panoramic radiographs and CT images of uninfected impacted maxillary third molars and investigated the pathway of infection originating from pericoronitis of maxillary third molars. Patients (n=62) with uninfected impacted maxillary third molars and patients (n=8) with odontogenic infection originating from pericoronitis of the maxillary third molars were selected from an image database. CT and panoramic images were evaluated separately by an oral surgeon and a radiologist for the vertical position of the tooth, the presence of bone around the crown, proximity to the maxillary sinus, visibility of masticatory muscles, and mesiodistal and buccopalatal inclinations. In uninfected patients, a significant correlation was observed between the vertical positions evaluated by the two methods. Of the third molars, 79 (63.7%) were identified as vertical type on both panoramic and CT images. Regarding the maxillary sinus, of the 19 molars classified as the separate type on panoramic images, 2 (10.5%) were identified as the close type on CT. CT examination revealed the involvement of buccal cortical plates and the buccal space in the majority of infected patients. CT images revealed that 94 molars (75.8%) showed vertical type on the buccopalatal inclination and that 45 impacted molars (36.3%) showed bone defects in the buccal area. Infections originating from pericoronitis of the maxillary third molar showed involvement of the buccal cortical plates, the buccal space, and other spaces, which were clearly depicted on CT images. (author)

  3. Prevalence and Pattern of Third Molar Impaction; A retrospective study of radiographs in Oman

    Directory of Open Access Journals (Sweden)

    Samira M. Al-Anqudi

    2014-08-01

    Full Text Available Objectives: The aim of this retrospective study was to investigate the prevalence and pattern of third molar impaction in patients between 19‒26 years old attending Sultan Qaboos University Hospital (SQUH in Muscat, Oman. Methods: The study reviewed 1,000 orthopantomograms (OPGs of patients attending the Oral Health Department of SQUH between October 2010 and April 2011. Patients were evaluated to determine the prevalence of third molar impaction, angulation, level of eruption and associated pathological conditions. Results: Of the study population, 543 (54.3% OPGs showed at least one impacted third molar. The total number of impacted molars was 1,128. The most common number of impacted third molars was two (41%. The most common angulation of impaction in the mandible was the mesioangular (35% and the most common level of impaction in the mandible was level A. Of the 388 bilateral occurrences of impacted third molars, 377 were in the mandible. There was no significant difference in the frequency of impaction between the right and left sides of both jaws. Pathological conditions associated with impacted lower third molars were found in 18%, of which 14% were associated with a radiographic radiolucency of more than 2.5 mm, and 4% of impacted lower third molars were associated with dental caries. Conclusion: This study found that more than half of Omani adult patients ranging in age from 19‒26 years had at least one impacted third molar.

  4. Three-dimensional analysis of third molar development to estimate age of majority.

    Science.gov (United States)

    Márquez-Ruiz, Ana Belén; Treviño-Tijerina, María Concepción; González-Herrera, Lucas; Sánchez, Belén; González-Ramírez, Amanda Rocío; Valenzuela, Aurora

    2017-09-01

    Third molars are one of the few biological markers available for age estimation in undocumented juveniles close the legal age of majority, assuming an age of 18years as the most frequent legal demarcation between child and adult status. To obtain more accurate visualization and evaluation of third molar mineralization patterns from computed tomography images, a new software application, DentaVol©, was developed. Third molar mineralization according to qualitative (Demirjian's maturational stage) and quantitative parameters (third molar volume) of dental development was assessed in multi-slice helical computed tomography images of both maxillary arches displayed by DentaVol© from 135 individuals (62 females and 73 males) aged between 14 and 23years. Intra- and inter-observer agreement values were remarkably high for both evaluation procedures and for all third molars. A linear correlation between third molar mineralization and chronological age was found, with third molar maturity occurring earlier in males than in females. Assessment of dental development with both procedures, by using DentaVol© software, can be considered a good indicator of age of majority (18years or older) in all third molars. Our results indicated that virtual computed tomography imaging can be considered a valid alternative to orthopantomography for evaluations of third molar mineralization, and therefore a complementary tool for determining the age of majority. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

  5. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....... hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...

  6. Indirect pulp capping in primary molar using glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Murtia Metalita

    2014-12-01

    Full Text Available Background: Indirect pulp capping in primary teeth, however, is more rarely conducted than permanent teeth, since it thought to have low impact and most suggestion is for taking caries lesion aggressively on primary teeth. Purpose: The study was aimed to evaluate the subjective complaint, clinical symptom, and radiographic appearance of indirect pulp capping treatment using glass ionomers cements in primary molar. Methods: Sixteen children in range of age 6 to 8 years old, who visited Clinic of Pediatric Dentistry Universitas Airlangga Dental Hospital, Surabaya Indonesia, were the subject of study. They had one occlusal dental caries on one side of maxillary or mandibular primary molar with the diagnose of pulpitis reversible. The experimental group, had indirect pulp capping treatment with glass ionomer cements (GC Fuji VII®, while the control group, had indirect pulp capping treatment with calcium hydroxide (Metapaste. Each group was filled with GC Fuji IX® as permanent restoration. After one week, one month, and three months later, the observations were made on subjective complaint, clinical symptom, and radiographic appearance. Results: The results showed no subjective complaint such as pain or problem on mastication; no negative clinical symptoms such as pain on palpation, gingivitis or periodontitis, and abnormal tooth mobility; no negative radiographic appearance such as pathological apical radioluscency, internal or external resorbtion, and change of ligament periodontal widthafter the treatment. Conclusion: The study suggested that indirect pulp capping treatment using glass ionomer cement materials on primary teeth might be considered to be the treatment choice.Latar belakang: Indirect pulp capping pada gigi sulung lebih jarang dilakukan dibandingkan gigi permanen, karena dianggap memiliki dampak yang rendah dan sebagian besar menyarankan untuk mengambil lesi karies secara agresif pada gigi sulung. Tujuan: Penelitian ini bertujuan

  7. Ectopic third molar in maxillary sinus: A rare case report

    Directory of Open Access Journals (Sweden)

    Abhishek Sinha

    2017-01-01

    Full Text Available Ectopic tooth eruption in a non-dental area is a rare entity, and is most common in oral cavity. There have been a few case reports of teeth erupting in mandibular condyle, chin, palate, coronoid process, and maxillary sinus. Ectopic tooth in the maxillary sinus are found incidentally on routine radiological examination, same time they can be symptomatic and associated with pathologies usually dentigerous cyst or odontogenic keratocyst. Facial pain, purulent rhinorrhoea, epistaxis, headache, swelling, and epiphora-related naso-lacrimal duct obstruction can also be seen. By Caldwell-Luc procedure the ectopic teeth within the maxillary sinus are often removed. In this study, a case of ectopic maxillary third molar tooth on right maxillary sinus is presented.

  8. Efficiency of Intraligamentary Anesthesia of Inferior Molars for Endodontic Treatment

    Directory of Open Access Journals (Sweden)

    Peycheva K.

    2014-12-01

    Full Text Available The periodontal ligament injection appears to be the most consistently reliable in achieving clinically adequate pulpal anaesthesia. Materials and Methods: 130 inferior molar teeth; technique: The tooth was first cleaned with chlorhexidine 0.2% solution. The penetration of the ligament is performed with special intraligamentary needle (30 G - 9, 17,21 mm “sliding” along the side of the tooth, 300º angle between the needle and the tooth, having taken the care of determining support points which will prevent the needle from twisting. The penetration must be deep enough to obtain the seal required for the injection, injection for each root in particular points; volume of solution per root is 0.2-0.4 ml. Results: In 125 cases the technique was absolutely efficient. In only 5 cases with pulpitis chronica ulcerosa there was need for additional intrapulpal anesthesia. Conclusions: The method could be used as a primary anesthetic method for endodontic treatment.

  9. Revascularization and Apical Plug in an Immature Molar

    Science.gov (United States)

    Roghanizadeh, Leyla; Fazlyab, Mahta

    2018-01-01

    Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year follow-up, both procedures were successful in relieving patient’s symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development. PMID:29692851

  10. Physicochemical characterization of irradiated high molar mass chitosan

    International Nuclear Information System (INIS)

    Rapado, Manuel; Paredes, Mayte; Altanes, Sonia; Barrera, Gisela; Otero, Isabel; Peniche, Carlos; Gonzalez, Maykel

    2006-01-01

    The present study is aimed to determination of the bio burden for assessing the sterilization dose and to identify the influence of the absorbed dose of gamma radiation on the molar mass and chemical structure of chitosan. The characterization includes the determination of the intrinsic viscosity, deacetylation degree as well as infrared spectrometry. The obtained results have been shown chain cleavage caused by irradiation. It was revealed by a decrease in the intrinsic viscosities of the polymers. The invariance of the infrared spectra of polymers indicated that chain degradation occurs without significant change of the chemical structure. The results obtained have practical implication in the field of radiation sterilization of chitosan used for microencapsulation of mammalian cells

  11. Molar extinction coefficients of some commonly used solvents

    International Nuclear Information System (INIS)

    Kumar, Ashok; Singh, Sukhpal; Singh Mudahar, Gurmel; Singh Thind, Kulwant

    2006-01-01

    Molar extinction coefficients of some commonly used solvents (ethanol (C 2 H 5 OH), methanol (CH 3 OH), propanol (C 3 H 7 OH), butanol (C 4 H 9 OH), water (H 2 O), toluene (C 7 H 8 ), benzene (C 6 H 6 ), carbontetrachloride (CCl 4 ), acetonitrile (C 4 H 3 N), chlorobenzene (C 6 H 5 Cl), diethylether (C 4 H 1 O) and dioxane (C 4 H 8 O 2 )) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV γ rays. The total γ ray interaction cross sections of these solvents have also been determined. A good agreement has been obtained between the experimental results with the theoretical values evaluated through XCOM calculations

  12. Prediction of postoperative pain after mandibular third molar surgery

    DEFF Research Database (Denmark)

    Rudin, Asa; Eriksson, Lars; Liedholm, Rolf

    2010-01-01

    . Standardized surgery was performed during local anesthesia. Postoperative pain management was with rescue paracetamol and ibuprofen. The patients were instructed to record each day their pain at rest and during dynamic conditions, and their requirement of analgesics for 14 days following surgery.......To evaluate the predictive potential of preoperative psychological and psychophysiological variables in estimating severity of postoperative pain following mandibular third molar surgery (MTMS). Methods: Following ethical committee approval and informed consent, 40 consecutive patients scheduled...... for MTMS were included. Preoperative psychometric indicators of anxiety, depression, and vulnerability were evaluated by patient questionnaires. Thermal thresholds and heat pain perception (1 second phasic stimuli: 44 degrees C to 48 degrees C) were evaluated with quantitative sensory testing techniques...

  13. Standard molar enthalpies of formation of hydroxy-, chlor-, and bromapatite

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Fernando J.A.L. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico 1049-001 Lisbon (Portugal); Minas da Piedade, Manuel E. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisbon (Portugal); Calado, Jorge C.G. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico 1049-001 Lisbon (Portugal)]. E-mail: jcalado@ist.utl.pt

    2005-10-15

    The standard (p{sup 0} =0.1MPa) molar enthalpies of formation in the crystalline state of hydroxyapatite, chlorapatite and a preliminary value for bromapatite, at T=298.15K, were determined by reaction-solution calorimetry as: {delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2},cr]=-(13399+/-11)kJ.mol{sup -1},{delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}Cl{sub 2},cr]=-(13231+/-82)kJ.mol{sup -1},and{delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}Br{sub 2},cr]=-(13063+/-81)kJ.mol{sup -1}. A critical assessment of these results and of previously published data is made. Finally, the standard molar enthalpy of formation of iodapatite is estimated as {delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}I{sub 2},cr]=-12949kJ.mol{sup -1}, from a linear correlation of {delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}X{sub 2},cr] (X=OH, F, Cl, Br) against the corresponding {delta}{sub f}H{sub m}{sup 0} [CaX{sub 2},cr].

  14. Piezosurgery or conventional rotatory instruments for inferior third molar extractions?

    Science.gov (United States)

    Piersanti, Luigi; Dilorenzo, Matteo; Monaco, Giuseppe; Marchetti, Claudio

    2014-09-01

    The purpose of this study was to compare the discomfort and surgical outcomes of a piezosurgery device with those of rotatory instruments in lower third molar extraction. A split-mouth, randomized, unblinded clinical study was designed; the 2 molars had to have the same extraction difficulty score. The test side was extracted using a piezosurgery technique and the control side was extracted using a conventional handpiece. The primary endpoint was patient discomfort evaluated with the Postoperative Symptom Severity (PoSSe) scale, which was administered to each patient; secondary endpoints were pain, trismus, swelling, and surgical time evaluation. Paired-samples t test and repeated-measures analysis of variance were used to compare outcomes within patients. Ten consecutive patients (6 female, 4 male; mean age, 22.4 ± 2.3 yr) were recruited. The total score on the PoSSe scale was significantly lower for piezosurgery compared with the conventional rotating handpiece (24.7 ± 10.3 vs 36.0 ± 7.6; t = -4.27; P = .002). Moreover, postoperative swelling 1 week after surgery was significantly lower for piezosurgery than for the conventional rotating handpiece (2.75 ± 0.23 vs 3.1 ± 0.39 cm; t = -2.63; P = .027). Piezosurgery was associated with less postoperative discomfort and yielded better results for swelling. Piezosurgery seems to be a good technique in daily surgical practice, especially if applied in the critical steps in which safety and respect for soft tissue, bone, and nerves are necessary. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  15. Radiation absorbed doses at radiographic examination of third molars.

    Science.gov (United States)

    Rehnmark-Larsson, S; Stenström, B; Julin, P; Richter, S

    1982-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. In the maxilla three, and in the mandible four different projections were used; also an extraoral lateral view. The greatest thyroid dose, 35 muGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. the thyroid dose from an extraoral lateral view with high sensitivity screens was 3.7 muGy. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. The corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50%. the Ekta-Speed film required approximately 40% lower exposure than the Ultra-Speed film. Without shielding the gonadal doses from a complete examination of four third molars were of the same order of magnitude as from a full survey with intraoral films, i.e. 3-7 muGy. A horizontal radiation shield reduced the thyroid doses by between 12 and 46% and the gonadal doses by between 50 and 95%. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses by between 15 and 42% and the gonadal doses by two orders of magnitude.

  16. Detection of Mesiobuccal Canal in Maxillary Molars and Distolingual Canal in Mandibular Molars by Dental CT: A Retrospective Study of 100 Cases

    Directory of Open Access Journals (Sweden)

    Sushma Rathi

    2010-01-01

    Full Text Available Objective. To detect presence of MB2 canal in maxillary molars and distolingual canal in mandibular molars by Dental CT. Material and Methods. A retrospective study of 100 Dental CTs was done. Axial and paraxial images obtained were used to assess the presence of MB2 canal in maxillary molars and distolingual canal in mandibular molars. Results. The youngest patient was of 11 years while the eldest patient was of 77 years. Males were 58 in number and females were 42 in number. MB2 canals were present in 57 patients and distolingual canal was present in 18 patients. Maximum MB2 canals were present in age group between 51 and 60 years, while distolingual canals were present in age group of 21–30 years. Conclusion. Dental CT allows adequate visualization of variation in root canal morphology and can be important diagnostic tool for successful endodontic therapy.

  17. Computed tomographic anatomy of the mandibular first and second molars and their surrounding structures in the spread of odontogenic infection

    International Nuclear Information System (INIS)

    Ohshima, Aya; Ariji, Yoshiko; Gotoh, Masakazu; Izumi, Masahiro; Naitoh, Munetaka; Kurita, Kenichi; Shimozato, Kazuo; Ariji, Eiichiro

    2009-01-01

    The purposes of this study were to analyze the CT anatomy of the mandibular first and second molars in uninfected subjects and to clarify the pathway of odontogenic infection originating from the mandibular first and second molars. CT anatomies, especially for bucco-lingual aspects and the surrounding soft tissues, were investigated in 100 uninfected subjects and 17 infected patients. At the level of bifurcation, disappearance of the cortical plates was frequently observed on the buccal and lingual sides of the first molars, and it was reduced on the buccal side in the second molar. In the first molar, the bony width was thinner on the buccal than the lingual side. The lingual cortices were thinner in the second molar. All medial pterygoid and 88% of masseter muscles were situated posteriorly, without horizontally overlapping the second molar, whereas the mylohyoid muscle (MhM) overlapped horizontally with the first and second molars. The MhM was positioned superior to the root apices in 10 and 39% of first and second molars, respectively. All patients with first molar infection showed involvement of buccal structures, and one showed lingual side involvement. In contrast, six of nine patients with second molar infection showed involvement on the lingual side. Infection originating from the second molar was more likely to spread to the lingual side than infection originating from the first molar. CT anatomy surrounding the causal teeth supported the spread pathways of mandibular first and second molar infection. (author)

  18. New quantitative classification of the anatomical relationship between impacted third molars and the inferior alveolar nerve

    International Nuclear Information System (INIS)

    Wang, Wei-Quan; Chen, Michael Y. C.; Huang, Heng-Li; Fuh, Lih-Jyh; Tsai, Ming-Tzu; Hsu, Jui-Ting

    2015-01-01

    Before extracting impacted lower third molars, dentists must first identify the spatial relationship between the inferior alveolar nerve (IAN) and an impacted lower third molar to prevent nerve injury from the extraction. Nevertheless, the current method for describing the spatial relationship between the IAN and an impacted lower third molar is deficient. Therefore, the objectives of this study were to: (1) evaluate the relative position between impacted lower third molars and the IAN; and (2) investigate the relative position between impacted lower third molars and the IAN by using a cylindrical coordinate system. From the radiology department’s database, we selected computed tomography images of 137 lower third molars (from 75 patients) requiring removal and applied a Cartesian coordinate system by using Mimics, a medical imaging software application, to measure the distribution between impacted mandibular third molars and the IAN. In addition, the orientation of the lower third molar to the IAN was also measured, but by using a cylindrical coordinate system with the IAN as the origin. According to the Cartesian coordinate system, most of the IAN runs through the inferior side of the third molar (78.6 %), followed by the lingual side (11.8 %), and the buccal side (8.9 %); only 0.7 % is positioned between the roots. Unlike the Cartesian coordinate system, the cylindrical coordinate system clearly identified the relative position, r and θ, between the IAN and lower third molar. Using the cylindrical coordinate system to present the relationship between the IAN and lower third molar as (r, θ) might provide clinical practitioners with a more explicit and objective description of the relative position of both sites. However, comprehensive research and cautious application of this system remain necessary

  19. The prevalence and pattern of deciduous molar hypomineralization and molar-incisor hypomineralization in children from a suburban population in Nigeria

    OpenAIRE

    Temilola, Oluwaseyi Dada; Folayan, Morenike Oluwatoyin; Oyedele, Titus

    2015-01-01

    Background Molar Incisor Hypoplasia (MIH) and Deciduous Molar Hypoplasia (DMH) have significant impact on the quality of life of affected individuals. The objective of the study was to determine the prevalence, pattern and clinical presentation of MIH and DMH in children resident in Ile-Ife, Nigeria, and their association with sex and socioeconomic status of the children. Methods Information on age, sex and socioeconomic status was collected from 563 children aged 3 to 5?years and 8 to 10?yea...

  20. Incisor and molar overjet, arch contraction, and molar relationship in the mixed dentition in repaired complete unilateral cleft lip and palate: A qualitative and quantitative appraisal.

    Science.gov (United States)

    Disthaporn, Suteeta; Suri, Sunjay; Ross, Bruce; Tompson, Bryan; Baena, Diogenes; Fisher, David; Lou, Wendy

    2017-07-01

    To compare the mixed dentition incisor and molar overjet, severity of contraction of the dental arch, and the sagittal molar relationship on the cleft side vs the noncleft side in children with repaired complete unilateral cleft of the lip and palate (UCLP). Orthodontic records taken prior to orthodontic preparation for alveolar bone grafting were screened to select study casts from patients with nonsyndromic repaired complete UCLP who did not have mandibular skeletal or dental asymmetry. The study sample comprised dental casts from 74 children aged 8.9 ± 1 years. Standardized digital photographs were acquired at 1:1 magnification. A coordinate system was developed using digital image-processing software (Photoshop CS4 and Adobe Illustrator). Incisor and molar overjet, Angle's classification, and arch contraction were recorded. Descriptive statistics, paired t-tests, and kappa statistics were used to compare the cleft and noncleft sides. A negative overjet of -1 to -5 mm was often present at the incisors, with greater frequency and magnitude on the cleft side. Class II molar relation was more frequent on the cleft side (61.1%) than on the noncleft side (47.2%). Significantly greater contraction of the cleft side deciduous canine and deciduous first molar was noted, while the difference was very minor at the first permanent molar. Cleft side maxillary arch contraction was most severe in the deciduous canine and first deciduous molar region and progressively less severe in the posterior region of the arch. A greater frequency and severity of negative overjet and Class II molar relationship was seen on the cleft side.

  1. Permanent first molar extraction in adolescents and young adults and its effect on the development of third molar.

    Science.gov (United States)

    Halicioglu, Koray; Toptas, Orcun; Akkas, Ismail; Celikoglu, Mevlut

    2014-01-01

    The aim of the present study was to determine the prevalence of permanent first molar (P1M) extraction among Turkish adolescents and young adult subpopulation, and to investigate the effects of P1M extraction on development of the third molars (3Ms) in the same quadrant. A retrospective study including 2,925 panoramic radiographs (PRs) taken from patients (aged 13-20 years) who were examined to identify cases of had at least one maxillary or mandibular P1Ms extracted was performed. Additionally, 294 PRs with the maxillary or mandibular unilateral loss of a P1M were used to assess the developmental grades of the 3Ms. Statistical analyses were performed by means of parametric tests after performing a Shapiro-Wilks normality test to the data. A total of 945 patients (32.3 %) presented with at least one P1M extraction with no gender difference (P = 0.297). There were more cases of mandibular P1Ms extracted (784 patients, 1,066 teeth) than maxillary P1Ms extracted (441 patients, 549 teeth) (P development of the 3Ms on the extraction side, in the both maxilla and mandible, was significantly accelerated when compared with the contralateral teeth (P = 0.000, P = 0.000, respectively). No statistically significant differences were found in the differences in the developmental of the 3Ms between the maxilla and mandible (P = 0.718). High prevalence of P1Ms extraction among Turkish adolescents and young adults shows a need for targeted dental actions, including prevention and treatment. The development of the 3Ms on the extraction side, in the both maxilla and mandible, was significantly accelerated. To date, no information about prevalence of P1Ms extraction among Turkish adolescents and young adults is documented. In addition, the present study has a larger population and complementary information about 3Ms development than previous studies.

  2. Molar mass of poly(ethylene terephthalate) (PET) during ultimate uniaxial drawing

    NARCIS (Netherlands)

    Göschel, U.; Cools, P.J.C.H.

    2000-01-01

    The changes of the average molar mass Mw, Mn, Mz, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection:

  3. Molar-Mass of Poly(Ethylene-Terephthalate) (PET) During Ultimate Uniaxial Drawing

    NARCIS (Netherlands)

    Göschel, A.G.P.U.; Cools, P.J.C.H.

    2000-01-01

    The changes of the average molar mass Mw, Mn, Mz, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection:

  4. Psychological impact of third molar surgery: a 1-month prospective study

    NARCIS (Netherlands)

    de Jongh, Ad; van Wijk, Arjen J.; Lindeboom, Jerome A.

    2011-01-01

    To prospectively examine the psychological impact of surgical third molar removal, and to identify possible psychological risk factors for the development of dental anxiety and symptoms of psychological trauma. Patients (N = 71) scheduled for surgical mandibular third molar removal were assessed

  5. Morphology and chemical composition of dentin in permanent first molars with the diagnose MIH

    NARCIS (Netherlands)

    Heijs, Suzanne C. B.; Dietz, Wolfram; Noren, Jorgen G.; Blanksma, Nynke G.; Jalevik, Birgitta

    2007-01-01

    The purpose of this investigation was to study the morphology and distribution of some inorganic elements in dentin in first permanent molars from children with Molar-Incisor Hypomineralization (MIH). Sixty four tooth sections from thirty two children were examined in polarized light. Fifteen

  6. Functional approach to a Class II patient with upper first molar impaction

    Directory of Open Access Journals (Sweden)

    Giacomo D′Orlandi

    2014-01-01

    Full Text Available The lack of the left first molar maxillary and the left second molar maxillary, caused respectively by impaction and agenesis is a very rare case, which determines an important occlusal imbalance and asymmetrical mandible movement. A gnatologic and functional orthodontic approach were planned to improve the retrognathic mandible and the muscular activity using kinesiograph and electromyography.

  7. Origin of choriocarcinoma in previous molar pregnancy proved by DNA analysis

    International Nuclear Information System (INIS)

    Vojtassak, J.; Repiska, V.; Konecna, B.; Zajac, V.; Korbel, M.; Danihel, L.

    1996-01-01

    A 17-year old woman had in a short time period (seven months) a very exciting reproduction history. Molar pregnancy in December 1993, choriocarcinoma in January 1994 and induced abortion in June 1994. DNA analysis proved the origin of the choriocarcinoma in the previous molar pregnancy. (author)

  8. Root canal morphology of primary molars: a micro-computed tomography study.

    Science.gov (United States)

    Fumes, A C; Sousa-Neto, M D; Leoni, G B; Versiani, M A; da Silva, L A B; da Silva, R A B; Consolaro, A

    2014-10-01

    This was to investigate the root canal morphology of primary molar teeth using micro-computed tomography. Primary maxillary (n = 20) and mandibular (n = 20) molars were scanned at a resolution of 16.7 μm and analysed regarding the number, location, volume, area, structured model index (SMI), area, roundness, diameters, and length of canals, as well as the thickness of dentine in the apical third. Data were statistically compared by using paired-sample t test, independent sample t test, and one-way analysis of variance with significance level set as 5%. Overall, no statistical differences were found between the canals with respect to length, SMI, dentine thickness, area, roundness, and diameter (p > 0.05). A double canal system was observed in the mesial and mesio-buccal roots of the mandibular and maxillary molars, respectively. The thickness in the internal aspect of the roots was lower than in the external aspect. Cross-sectional evaluation of the roots in the apical third showed flat-shaped canals in the mandibular molars and ribbon- and oval-shaped canals in the maxillary molars. External and internal anatomy of the primary first molars closely resemble the primary second molars. The reported data may help clinicians to obtain a thorough understanding of the morphological variations of root canals in primary molars to overcome problems related to shaping and cleaning procedures, allowing appropriate management strategies for root canal treatment.

  9. Management of early loss of first permanent molar: A new technique

    Directory of Open Access Journals (Sweden)

    B S Rajashekhara

    2012-01-01

    Full Text Available The loss of a permanent first molar in adolescent patient creates a need for early space maintenance and restoration of function. To ascertain function and esthetics, immediate treatments include interim restorative approaches. This paper describes a conservative, functional and cost-effective bridge as an interim restoration after the loss of permanent first molar in an early adolescent dentition.

  10. The analgesic efficacy of intravenous versus oral tramadol for preventing postoperative pain after third molar surgery

    NARCIS (Netherlands)

    Ong, Cliff K. S.; Lirk, Phillip; Tan, Juliana M. H.; Sow, Belle W. Y.

    2005-01-01

    The aim of this study was to compare the analgesic efficacy of single-dose preoperative intravenous versus oral tramadol for preventing pain after third molar surgery. Seventy-two patients undergoing elective third molar surgery were randomized to receive either intravenous (n = 36) or oral (n = 36)

  11. Using cone beam computed thomography in planning the extraction of impacted third molars

    Directory of Open Access Journals (Sweden)

    Vlahović Zoran

    2016-01-01

    Full Text Available The panoramic radiography is the most used diagnostic imaging method in planning impacted lower third molar extractions. However, often panoramic radiography does not provide enough information in treatment planning for performing safely surgical extraction of impacted third molars. CBCT (Cone beam computed tomography provides more precise information in diagnostic analysis especially for planning surgical procedures where complications can be expected due to close relationship between mandibular canal and lower impacted third molars. The aim of this study is comparative analysis of panoramic radiography and CBCT in evaluating the topographic relationship between mandibular canal and impacted third molars. The study included 50 patients with close relationship between mandibular canal and impacted third molars detected using panoramic radiography. After panoramic radiography analysis CBCT was performed in order to diagnose, plan and prevent complications during the surgical tooth extraction. CBCT examination considered comparative analysis with panoramic radiography, marking, volume rendering and assessment of mandibular canal in buccolingual direction. Out of total patients where suprimposition of mandibular canal and impacted third molar on panoramic radiography was detected, in 32 patients mandibular chanal was localised on lingual side. Mandibular canal was positioned at bucal side in 18 of 50 patients. Results of this research indicate that panoramic radiography can be useful in everyday practice for diagnosis, planning and preparing lower third molar extractions, but in cases where close relationship between mandibular canal and lower third molars is detected CBCT is recommended as more precise radiographic imaging method in order to prevent complications.

  12. Micro-CT analyses of apical enlargement and molar root canal complexity

    DEFF Research Database (Denmark)

    Markvart, Merete; Darvann, Tron Andre; Larsen, Per

    2012-01-01

    AIM: To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical enlargement in molar teeth and to quantify and visualize spatial details of instrumentation efficacy in root canals of different complexity. METHODOLOGY: Maxillary and mandibular molar teeth wer...

  13. Reimbursement rates and policies for primary molar pit-and-fissure sealants across state Medicaid programs.

    Science.gov (United States)

    Chi, Donald L; Singh, Jennifer

    2013-11-01

    Little is known about Medicaid policies regarding reimbursement for placement of sealants on primary molars. The authors identified Medicaid programs that reimbursed dentists for placing primary molar sealants and hypothesized that these programs had higher reimbursement rates than did state programs that did not reimburse for primary molar sealants. The authors obtained Medicaid reimbursement data from online fee schedules and determined whether each state Medicaid program reimbursed for primary molar sealants (no or yes). The outcome measure was the reimbursement rate for permanent tooth sealants (calculated in 2012 U.S. dollars). The authors compared mean reimbursement rates by using the t test (α = .05). Seventeen Medicaid programs reimbursed dentists for placing primary molar sealants (34 percent), and the mean reimbursement rate was $27.57 (range, $16.00 [Maine] to $49.68 [Alaska]). All 50 programs reimbursed dentists for placement of sealants on permanent teeth. The mean reimbursement for permanent tooth sealants was significantly higher in programs that reimbursed for primary molar sealants than in programs that did not ($28.51 and $23.67, respectively; P = .03). Most state Medicaid programs do not reimburse dentists for placing sealants on primary molars, but programs that do so have significantly higher reimbursement rates. Medicaid reimbursement rates are related to dentists' participation in Medicaid and children's dental care use. Reimbursement for placement of sealants on primary molars is a proxy for Medicaid program generosity.

  14. The third molar as an age marker in adolescents: new approach to age evaluation.

    Science.gov (United States)

    Rozkovcova, Eva; Dostalova, Tatjana; Markova, Marie; Broukal, Zdenek

    2012-09-01

    Adolescence is a relatively short period between childhood and adulthood. It is very difficult to determine adulthood based on biological indicators. The third molar may be considered a potential age marker for the period between the ages of 16-21. Our study evaluated a set of 1700 panoramic radiographs of individuals aged between 5 and 21 years. Results confirmed the statistically significant difference in the course of third molars development. The mean deviation for individuals with one third molar agenesis is -0.98 years, for individuals with two third molars agenesis -1.89 years, and with three molars agenesis -3.28 years. Thus, the extent of the deviation is directly proportional to the number of unformed third molars. The calculation of age according to the mean of stages of all third molars could lead to the underestimation of age. No intergender differences were found. Age determination using third molars could be used for forensic purposes. © 2012 American Academy of Forensic Sciences.

  15. Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults.

    Science.gov (United States)

    Karadayi, Beytullah; Kaya, Ahsen; Kolusayın, Melek Ozlem; Karadayi, Sükriye; Afsin, Hüseyin; Ozaslan, Abdi

    2012-11-01

    Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15-23 years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22 years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars' eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.

  16. Evaluation of third molar development and its relation to chronological age: a panoramic radiographic study.

    Science.gov (United States)

    Zandi, Mohammad; Shokri, Abbas; Malekzadeh, Hamid; Amini, Payam; Shafiey, Parastu

    2015-06-01

    Third molar development, in comparison to other teeth in the dentition, has the greatest variation in morphology, anatomical position, and time of development and eruption, and its reliability for chronological age estimation is controversial. The aim of the present study was to evaluate third molar development and its relation to chronological age using panoramic radiography. A total of 2536 digital panoramic radiographs of individuals aged between 5 and 26 years were selected. The developmental status of the third molars was assessed using eight-stage developmental scoring proposed by Demirjian et al., with one modification: a stage 0 was added. The collected data were entered into a checklist and subjected to statistical analyses. The mean ages of the first appearance of third molar bud, complete crown formation, and root apex closure were around 9, 14, and 22 years, respectively. In both jaws, third molar development occurred symmetrically, and sexual dimorphism was observed at some developmental stages. Finally, two formulas were presented to estimate age of the juveniles and adolescents based on their gender and developmental stages of the third molars, and validated on a second sample consisting of 523 individuals aged between 8 and 22. Assessment of third molar development was found to be a reliable method for age estimation of individuals between 11 and 22 years. Because of possible ethnic and geographic differences in third molar development, population specific researches were recommended.

  17. Age of majority assessment in Dutch individuals based on Cameriere's third molar maturity index

    NARCIS (Netherlands)

    Boyacıoğlu Doğru, H.; Gulsahi, A.; Burçak Çehreli, S.; Galić, I.; van der Stelt, P.; Cameriere, R.

    2018-01-01

    Radiological examination of the third molar is done in living individuals for estimation of chronological age, especially in the late adolescence. The aim of this study was to assess the application of Cameriere's third molar maturity index (I3M) to determine whether an individual is 18 years or

  18. Hypomineralized second primary molars: prevalence data in Dutch 5-year-olds

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Schuller, A.A.; Weerheijm, K.L.; Veerkamp, J.S.J.

    2008-01-01

    The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar

  19. Patterns of third-molar agenesis and associated dental anomalies in an orthodontic population.

    Science.gov (United States)

    Celikoglu, Mevlut; Bayram, Mehmet; Nur, Metin

    2011-12-01

    The aim of this study was to investigate the frequency of dental anomalies in orthodontic patients with different patterns of third-molar agenesis, comparing them with patients without third-molar agenesis. A sample of 374 patients with agenesis of at least 1 third molar was divided into 4 groups according to the third-molar agenesis pattern, and a control group of 98 patients without third-molar agenesis was randomly selected from the patient archives. Panoramic radiographs and cast models were used to determine the associated dental anomalies, such as hypodontia, hyperdontia, impaction, dilaceration, microdontia, ectopic eruption, transposition, and transmigration. The Pearson chi-square and Fisher exact tests were used to determine the differences in the distribution of the associated dental anomalies among the groups. The prevalence of agenesis of other teeth (11.2%, n = 42) was significantly greater in our study sample (groups 1-4) than in the control group (group 5) (4.1%, n = 4; P dental anomalies in patients with agenesis of 3 and 4 third molars compared with the control group. Permanent tooth agenesis, microdontia of maxillary lateral incisors, and total dental anomalies are more frequently associated with agenesis of 4 third molars than with the presence of third molars. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  20. Molar mass determination of lignins by size-exclusion chromatography: towards standardisation of the method

    NARCIS (Netherlands)

    Baumberger, S.; Abaecherli, A.; Fasching, M.; Gellerstedt, G.; Gosselink, R.J.A.; Hortling, B.; Li, J.; Saake, B.; Jong, de E.

    2007-01-01

    The reactivity and physicochemical properties of lignins are partly governed by their molar mass distribution. The development of reliable standard methods for determination of the molar mass distribution is not only relevant for designing technical lignins for specific applications, but also for

  1. Modified distal shoe appliance for premature loss of multiple deciduous molars: a case report.

    Science.gov (United States)

    Bhat, Prasanna Kumar; K, Navin H; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

    2014-08-01

    Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist's armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars.

  2. Accurate and sensitive determination of molar fractions of "1"3C-Labeled intracellular metabolites in cell cultures grown in the presence of isotopically-labeled glucose

    International Nuclear Information System (INIS)

    Fernández-Fernández, Mario; Rodríguez-González, Pablo; Hevia Sánchez, David; González-Menéndez, Pedro; Sainz Menéndez, Rosa M.; García Alonso, J. Ignacio

    2017-01-01

    This work describes a methodology based on multiple linear regression and GC-MS for the determination of molar fractions of isotopically-labeled intracellular metabolites in cell cultures. Novel aspects of this work are: i) the calculation of theoretical isotopic distributions of the different isotopologues from an experimentally measured value of % 13C enrichment of the labeled precursor ii) the calculation of the contribution of lack of mass resolution of the mass spectrometer and different fragmentation mechanism such as the loss or gain of hydrogen atoms in the EI source to measure the purity of the selected cluster for each metabolite and iii) the validation of the methodology not only by the analysis of gravimetrically prepared mixtures of isotopologues but also by the comparison of the obtained molar fractions with experimental values obtained by GC-Combustion-IRMS based on "1"3C/"1"2C isotope ratio measurements. The method is able to measure molar fractions for twenty-eight intracellular metabolites derived from glucose metabolism in cell cultures grown in the presence of "1"3C-labeled Glucose. The validation strategies demonstrate a satisfactory accuracy and precision of the proposed procedure. Also, our results show that the minimum value of "1"3C incorporation that can be accurately quantified is significantly influenced by the calculation of the spectral purity of the measured cluster and the number of "1"3C atoms of the labeled precursor. The proposed procedure was able to accurately quantify gravimetrically prepared mixtures of natural and labeled glucose molar fractions of 0.07% and mixtures of natural and labeled glycine at molar fractions down to 0.7%. The method was applied to initial studies of glucose metabolism of different prostate cancer cell lines. - Highlights: • Determination of molar fractions of "1"3C-labeled metabolites in cell cultures. • The method is based on multiple linear regression and GC-MS. • Validation of the method by

  3. Accurate and sensitive determination of molar fractions of {sup 13}C-Labeled intracellular metabolites in cell cultures grown in the presence of isotopically-labeled glucose

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Fernández, Mario [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo (Spain); Rodríguez-González, Pablo, E-mail: rodriguezpablo@uniovi.es [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo (Spain); Hevia Sánchez, David; González-Menéndez, Pedro; Sainz Menéndez, Rosa M. [University Institute of Oncology (IUOPA), University of Oviedo, Julián Clavería 6, 33006 Oviedo (Spain); García Alonso, J. Ignacio [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo (Spain)

    2017-05-29

    This work describes a methodology based on multiple linear regression and GC-MS for the determination of molar fractions of isotopically-labeled intracellular metabolites in cell cultures. Novel aspects of this work are: i) the calculation of theoretical isotopic distributions of the different isotopologues from an experimentally measured value of % 13C enrichment of the labeled precursor ii) the calculation of the contribution of lack of mass resolution of the mass spectrometer and different fragmentation mechanism such as the loss or gain of hydrogen atoms in the EI source to measure the purity of the selected cluster for each metabolite and iii) the validation of the methodology not only by the analysis of gravimetrically prepared mixtures of isotopologues but also by the comparison of the obtained molar fractions with experimental values obtained by GC-Combustion-IRMS based on {sup 13}C/{sup 12}C isotope ratio measurements. The method is able to measure molar fractions for twenty-eight intracellular metabolites derived from glucose metabolism in cell cultures grown in the presence of {sup 13}C-labeled Glucose. The validation strategies demonstrate a satisfactory accuracy and precision of the proposed procedure. Also, our results show that the minimum value of {sup 13}C incorporation that can be accurately quantified is significantly influenced by the calculation of the spectral purity of the measured cluster and the number of {sup 13}C atoms of the labeled precursor. The proposed procedure was able to accurately quantify gravimetrically prepared mixtures of natural and labeled glucose molar fractions of 0.07% and mixtures of natural and labeled glycine at molar fractions down to 0.7%. The method was applied to initial studies of glucose metabolism of different prostate cancer cell lines. - Highlights: • Determination of molar fractions of {sup 13}C-labeled metabolites in cell cultures. • The method is based on multiple linear regression and GC-MS.

  4. The rectilinear Steiner ratio

    Directory of Open Access Journals (Sweden)

    PO de Wet

    2005-06-01

    Full Text Available The rectilinear Steiner ratio was shown to be 3/2 by Hwang [Hwang FK, 1976, On Steiner minimal trees with rectilinear distance, SIAM Journal on Applied Mathematics, 30, pp. 104– 114.]. We use continuity and introduce restricted point sets to obtain an alternative, short and self-contained proof of this result.

  5. Standard molar enthalpies of formation and of sublimation of the terphenyl isomers

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Lima, Luis M. Spencer S.

    2008-01-01

    The standard (p 0 = 0.1 MPa) molar enthalpies of formation in the crystalline phases of ortho, meta and para-terphenyl isomers, at T = 298.15 K, were derived from the standard molar energies of combustion, measured by mini-bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the crystals with the temperature, thus deriving their standard molar enthalpies of sublimation by means of the Clausius-Clapeyron equation. Combining the standard molar enthalpies of formation and sublimation of the crystalline terphenyls, the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, were derived for the three isomers. Results are provided in a table. The results show small but detectable isomerization enthalpies between the terphenyls, indicating the following relative enthalpic stabilities: m- > p- ∼ o-terphenyl

  6. A New Anatomically Based Nomenclature for the Roots and Root Canals—Part 1: Maxillary Molars

    Directory of Open Access Journals (Sweden)

    Jojo Kottoor

    2012-01-01

    Full Text Available Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.

  7. C-shaped root canal in a maxillary first molar: a case report.

    Science.gov (United States)

    Yilmaz, Z; Tuncel, B; Serper, A; Calt, S

    2006-02-01

    This case report presents an unusual C-shaped root canal system in a maxillary first molar tooth. Although C-shaped root canals are most frequently seen in the mandibular second molar, they may also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. The present case describes a C-shaped canal in the buccal root of a maxillary first molar. The endodontic access cavity displayed two canal orifices, one leading to the canal system in the buccal root, the other into the palatal root canal system. In the buccal root, what appeared to be the mesial and distal canals joined to form a single C-shaped canal. --Careful examination of radiographs and the internal anatomy of teeth is essential.-- The location and morphology of root canals should be identified at high magnification under the microscope.

  8. A new anatomically based nomenclature for the roots and root canals-part 1: maxillary molars.

    Science.gov (United States)

    Kottoor, Jojo; Albuquerque, Denzil Valerian; Velmurugan, Natanasabapathy

    2012-01-01

    Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.

  9. Endodontic treatment of a maxillary second molar with developmental anomaly: a case report.

    Science.gov (United States)

    Asgary, Saeed

    2007-01-01

    Fusion is a rare occurrence in molar teeth. The purpose of this rare case presentation is to describe the nonsurgical endodontic treatment of maxillary molar. A 28-year-old patient was referred for endodontic treatment of her chronic apical abscess of right maxillary second molar. In the clinical examination, a sinus tract adjacent to involved tooth and a small crown of supernumerary tooth fused to the buccal surface of the molar at gingival margin was observed. Endodontic treatment was decided for the involved molar for functional reason. Recall examination, a year after completion of endodontic and restorative treatments, showed the tooth was clinically asymptomatic and there was no radiographic lucency around the apical region.

  10. Prevalence of Third Molar Agenesis: Associated Dental Anomalies in Non-Syndromic 5923 Patients.

    Science.gov (United States)

    Sujon, Mamun Khan; Alam, Mohammad Khursheed; Rahman, Shaifulizan Abdul

    2016-01-01

    The aim of this study was to investigate the prevalence of third molar agenesis and other associated dental anomalies in Bangladeshi population and to investigate the relationship of other dental anomalies with the third molar presence/agenesis. A retrospective study was performed using panoramic radiographs of 5923 patients, who ranged in age from 10 to 50 years. All radiographs were analyzed by Planmeca Romexis® 3.0 software (Planmeca Oy, Helsinki, Finland). Pearson chi-square and one way ANOVA (Post Hoc) test were conducted. The prevalence of third molar agenesis was 38.4%. The frequency of third molar agenesis was significantly higher in females than males (p dental anomalies was 6.5%, among them hypodontia was 3.1%. Prevalence of third molar agenesis varies in different geographic region. Among the other dental anomalies hypodontia was more prevalent.

  11. Excess molar enthalpies for binary mixtures of different amines with water

    International Nuclear Information System (INIS)

    Zhang, Ruilei; Chen, Jian; Mi, Jianguo

    2015-01-01

    Highlights: • Isothermal excess molar enthalpies for binary mixtures of different amines with water. • The Redlich–Kister equation and the NRTL model was used to fit the experimental data. • The excess molar enthalpies were discussed with different structures of amines. - Abstract: The isothermal excess molar enthalpies for binary mixtures of different amines with water were measured with a C-80 Setaram calorimeter. The experimental results indicate that the excess molar enthalpy is related to the molecular structure. The experimental excess molar enthalpies were satisfactorily fitted with the Redlich–Kister equation. They were also used to test the suitability of the NRTL model, and the deviations are a little larger than the R–K equation

  12. Characterization of stem and progenitor cells in the dental pulp of erupted and unerupted murine molars

    Science.gov (United States)

    Balic, Anamaria; Aguila, H. Leonardo; Caimano, Melissa J.; Francone, Victor P.; Mina, Mina

    2010-01-01

    In the past few years there have been significant advances in the identification of putative stem cells also referred to as “mesenchymal stem cells” (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulp from erupted molars displayed a reduced number of cells, contained higher percentage of CD45+ and lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts. PMID:20193787

  13. A combined experimental and computational investigation of excess molar enthalpies of (nitrobenzene + alkanol) mixtures

    International Nuclear Information System (INIS)

    Neyband, Razieh Sadat; Zarei, Hosseinali

    2015-01-01

    Highlights: • Excess molar enthalpies for the binary mixtures of nitrobenzene + alkanols mixtures were measured. • The infinite dilution excess partial molar enthalpies were calculated using the ab initio methods. • The PCM calculations were performed. • The computed excess partial molar enthalpies at infinite dilution were compared to experimental results. - Abstract: Excess molar enthalpies (H m E ) for the binary mixtures of {(nitrobenzene + ethanol), 1-propanol, 2-propanol, 1-butanol and 2-butanol} have been measured over the entire composition range at ambient pressure (81.5 kPa) and temperature 298 K using a Parr 1455 solution calorimeter. From the experimental results, the excess partial molar enthalpies (H i E ) and excess partial molar enthalpies at infinite dilution (H i E,∞ ) were calculated. The excess molar enthalpies (H m E ) are positive for all {nitrobenzene (1) + alkanol (2)} mixtures over the entire composition range. A state-of-the-art computational strategy for the evaluation of excess partial molar enthalpies at infinite dilution was followed at the M05-2X/6-311++G ∗∗ level of theory with the PCM model. The experimental excess partial molar enthalpies at infinite dilution have been compared to the computational data of the ab initio in liquid phase. Integrated experimental and computational results help to clarify the nature of the intermolecular interactions in {nitrobenzene (1) + alkanol (2)} mixtures. The experimental and computational work which was done in this study complements and extends the general research on the computation of excess partial molar enthalpy at infinite dilution of binary mixtures

  14. Comparison of Primary Molar Crown Dimensions with Stainless Steel Crowns in a Sample of Iranian Children

    Directory of Open Access Journals (Sweden)

    Hossein Afshar

    2015-06-01

    Full Text Available Background and aims. Due to anatomic variation in tooth anatomy between populations, this study compared the buccolingual (BL and mesiodistal (MD dimensions of primary molars with those of stainless steel crowns (SSCs in anIranian population. Materials and methods. Impressions were taken from both dental arches of children, and casts were poured. Teeth with caries, restoration, hypoplasia or other dental anomalies were excluded. 216 primary molars were selected and divided into 4 groups of 54 each (maxillary and mandibular first and second primary molars. MD/BL dimensions were measured using a digital caliper with 0.01 mm precision on casts and SCCs (3M brand. Data were assessed using paired t-test, post hoc test and ANOVA. P < 0.05 was considered statistically significant. Results. The MD dimension of the lower first molar SSC and the BL dimension of the lower second molar SSC had the least difference with the corresponding values of the respective teeth. The MD dimension of the upper second molar SSC and the BL dimension of the upper first molar SSC had the greatest difference with the corresponding values in the respective teeth. Comparison of the two different brands of SSCs for the upper first molar revealed that both types had significant differences with the teeth in terms of both MD (P = 0.0 and BL (P = 0.0 dimensions. Conclusion. In the studied population, best adaptation was seen in second lower molars and the least adaptationswere seen in first and second upper molars.

  15. Evaluation of telemedicine systems for impacted third molars diagnosis

    Directory of Open Access Journals (Sweden)

    Duka Miloš

    2009-01-01

    Full Text Available Background/Aim. In the last twenty years significant advances have been made in the fields of information and telecommunication technology in health care applications, with a positive impact on the health care practice. The need for remote diagnosis and planning of interventions is of special importance in military health care, and health management of immobile persons, and those with special needs. In cases such as these, availability of specialist health care is mainly limited by geographic and financial factors. The aim of this study was to investigate practical usability of telemedicine approaches in everyday management of oral surgery patients in terms of reliability of established diagnosis and indications for oral surgery treatment of the third molars. Methods. Our experimental randomized study enrolled 432 randomly selected patients of both genders, aged 20 to 87 years, undergoing panoramic radiography for some reason in the Centre for Dental Radiography in Belgrade. In addition to radiography, photographs of the face and mouth cavity were taken. These images were uploaded to the web server specially dedicated to the study purposes, and then transmitted to teledentists, i.e. oral surgeons, who made remote diagnoses. Diagnostic agreement was determined by way of the Cohen's kappa coefficient, and diagnostic sensitivity (SE, specificity (SP, and effectiveness (EFF were also established. Statistical significance was determined and comparisons performed by using the z-test, and testing of non-parametric characteristics by using the McNemar's χ2 test for p = 0.05 significance cut-off. Results. The results obtained by analyzed images and diagnostic assessment of the clinical diagnosis (kappa = 0.99, SE = 99%, SP = 99%, EFF = 99%, for 95% CI indicate an almost complete diagnostic agreement. The differences in diagnosis were not statistically significant. Conclusion. Diagnostic assessment of the clinical diagnosis of impacted or semi

  16. Transformer ratio enhancement experiment

    International Nuclear Information System (INIS)

    Gai, W.; Power, J. G.; Kanareykin, A.; Neasheva, E.; Altmark, A.

    2004-01-01

    Recently, a multibunch scheme for efficient acceleration based on dielectric wakefield accelerator technology was outlined in J.G. Power, W. Gai, A. Kanareykin, X. Sun. PAC 2001 Proceedings, pp. 114-116, 2002. In this paper we present an experimental program for the design, development and demonstration of an Enhanced Transformer Ratio Dielectric Wakefield Accelerator (ETR-DWA). The principal goal is to increase the transformer ratio R, the parameter that characterizes the energy transfer efficiency from the accelerating structure to the accelerated electron beam. We present here an experimental design of a 13.625 GHz dielectric loaded accelerating structure, a laser multisplitter producing a ramped bunch train, and simulations of the bunch train parameters required. Experimental results of the accelerating structure bench testing and ramped pulsed train generation with the laser multisplitter are shown as well. Using beam dynamic simulations, we also obtain the focusing FODO lattice parameters

  17. Intake to Production Ratio

    DEFF Research Database (Denmark)

    Nazaroff, William; Weschler, Charles J.; Little, John C.

    2012-01-01

    BACKGROUND: Limited data are available to assess human exposure to thousands of chemicals currently in commerce. Information that relates human intake of a chemical to its production and use can help inform understanding of mechanisms and pathways that control exposure and support efforts...... to protect public health.OBJECTIVES: We introduce the intake-to-production ratio (IPR) as an economy-wide quantitative indicator of the extent to which chemical production results in human exposure.METHODS: The IPR was evaluated as the ratio of two terms: aggregate rate of chemical uptake in a human......(n-butyl) phthalate, 1,040 ppm for para-dichlorobenzene, 6,800 ppm for di(isobutyl) phthalate, 7,700 ppm for diethyl phthalate, and 8,000-24,000 ppm (range) for triclosan.CONCLUSION: The IPR is well suited as an aggregate metric of exposure intensity for characterizing population-level exposure to synthesized...

  18. Morphometric evaluation of external root resorption of mandibular second molar teeth adjacent to the impacted third molars in CBCT imaging of Tehran\\'s population between 2011-2014

    Directory of Open Access Journals (Sweden)

    Fatemeh Ezoddini Ardakani

    2017-04-01

    Full Text Available Introduction: Presence of external root resorption in second molars associated with impacted mandibular third molars was not rare. The neglect of this issue may leads to penetration of the pulp and loss of the second molars. The aim of this study was to investigate the incidence and risk factors affecting the external root resorption in second molars associated with mandibular impacted third molars were inclined mesially and horizontally by Cone Beam Computer Tomography (CBCT images. Methods: In this cross sectional study the samples consisted of 231 scans with mesially and horizontally impacted mandibular third molars. Incidence of external root resorption of second molars and the effects of age, gender and clinical parameters such as location and intensity of external root resorption were considered. Moreover, depth and inclination of impacted mandibular third molar were evaluated by CBCT. The data were analyzed by Chi-square test. Results: The overall incidence of external root resorption in the second molars was 22.08%. Incidence of external root resorption in second molars was significantly related to gender and inclination of third molar. The relations between external root resorption and impaction depth of third molar or the patient's age was not statistically significant. However, the relationship between external root resorption and the intensity or depth of impacted third molar and location of root resorption was statistically meaningful. Conclusion: Patient’s gender and horizontal inclination of third molars are the most important factors affecting the presence of external root resorption in the second molars associated with mesially and horizontally impacted mandibular third molars.

  19. Trace element profiles in modern horse molar enamel as tracers of seasonality: Evidence from micro-XRF, LA-ICP-MS and stable isotope analysis

    Science.gov (United States)

    de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe

    2016-04-01

    A combination of laboratory micro-X-ray Fluorescence (μXRF) and stable carbon and oxygen isotope analysis shows that trace element profiles from modern horse molars reveal a seasonal pattern that co-varies with seasonality in the oxygen isotope records of enamel carbonate from the same teeth. A combination of six cheek teeth (premolars and molars) from the same individual yields a seasonal isotope and trace element record of approximately three years recorded during the growth of the molars. This record shows that reproducible measurements of various trace element ratios (e.g., Sr/Ca, Zn/Ca, Fe/Ca, K/Ca and S/Ca) lag the seasonal pattern in oxygen isotope records by 2-3 months. Laser Ablation-ICP-Mass Spectrometry (LA-ICP-MS) analysis on a cross-section of the first molar of the same individual is compared to the bench-top tube-excitation μXRF results to test the robustness of the measurements and to compare both methods. Furthermore, trace element (e.g. Sr, Zn, Mg & Ba) profiles perpendicular to the growth direction of the same tooth, as well as profiles parallel to the growth direction are measured with LA-ICP-MS and μXRF to study the internal distribution of trace element ratios in two dimensions. Results of this extensive complementary line-scanning procedure shows the robustness of state of the art laboratory micro-XRF scanning for the measurement of trace elements in bioapatite. The comparison highlights the advantages and disadvantages of both methods for trace element analysis and illustrates their complementarity. Results of internal variation within the teeth shed light on the origins of trace elements in mammal teeth and their potential use for paleo-environmental reconstruction.

  20. Hydrogen bonding interactions between ethylene glycol and water:density,excess molar volume,and spectral study

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Studies of the density and the excess molar volume of ethylene glycol (EG)-water mixtures were carried out to illustrate the hydrogen bonding interactions of EG with water at different temperatures. The re-sults suggest that a likely complex of 3 ethylene glycol molecules bonding with 4 water molecules in an ethylene glycol-water mixture (EGW) is formed at the maximal excess molar volume,which displays stronger absorption capabilities for SO2 when the concentration of SO2 reaches 400×10?6 (volume ratio) in the gas phase. Meanwhile,FTIR and UV spectra of EGWs were recorded at various EG concentra-tions to display the hydrogen bonding interactions of EG with water. The FTIR spectra show that the stretching vibrational band of hydroxyl in the EGWs shifts to a lower frequency and the bending vibra-tional band of water shifts to a higher frequency with increasing the EG concentration,respectively. Furthermore,the UV spectra show that the electron transferring band of the hydroxyl oxygen in EG shows red shift with increasing the EG concentration. The frequency shifts in FTIR spectra and the shifts of absorption bands in UV absorption spectra of EGWs are interpreted as the strong hydrogen bonding interactions of the hydrogen atoms in water with the hydroxyl oxygen atoms of EG.

  1. Digitized morphometric analysis of dental pulp of permanent mandibular second molar for age estimation of Davangere population.

    Science.gov (United States)

    Kumar, Nerella Narendra; Panchaksharappa, Mamatha Gowda; Annigeri, Rajeshwari G

    2016-04-01

    The aim of the present study is to estimate the age of Davangere population by evaluating the pulp to tooth area ratio (PTR) by using digitized intraoral periapical radiographs of permanent mandibular second molar. 400 intraoral periapical radiograph (IOPA) of permanent mandibular 2nd molar of both the sexes aged 14-60 years were used. Digital camera was used to image the radiographs. Images were computed and PTR was calculated by AUTOCAD software. Intra and Inter observer variability was also assessed. Regression analysis was used to estimate the age of an individual by taking PTR as dependent variable. The mean PTR of males and females was 0.10 ± 0.02 and 0.09 ± 0.02 respectively. Negative correlation was observed, when age was compared with PTR {r = -0.441, -0.406 & -0.419 among males, females and total subjects (p AUTOCAD software. Also high differences were observed between estimated and chronological age of 12 years which is not in the acceptable range. But it provides a new window for research in the forensic sciences in estimating the adult age. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  2. Clinical and radiographic comparison of platelet-rich fibrin and mineral trioxide aggregate as pulpotomy agents in primary molars

    Directory of Open Access Journals (Sweden)

    Surendra Patidar

    2017-01-01

    Full Text Available Aim: This study aimed to evaluate and compare the Platelet-rich fibrin (PRF and Mineral trioxide aggregate (MTA as a pulpotomy agent in primary molars. Material and Methods: In this study, 50 primary molars from 50 healthy children aged 5–9 years requiring pulpotomy were randomly allocated into two groups. In PRF group, after coronal pulp removal and hemostasis, remaining pulp tissue was covered with PRF preparation. In the MTA group, the pulp stumps were covered with MTA (Pro Root MTA-Root Canal Repair Material, Dentsply International Inc. paste obtained by mixing MTA powder with sterile water at a 3:1 powder to water ratio. All teeth were restored with reinforced zinc oxide eugenol base and glass – ionomer cement. Stainless steel crowns were given in both groups 24 h after treatment. Clinical evaluation was undertaken at 1, 3, and 6 months intervals whereas radiographic evaluation of the treated teeth was carried out at the interval of 6 months. Results: By the end of 6 months, the overall success rate was 90% in PRF group and 92% in MTA Group. A statistically significant difference was observed between the groups at 6 months of follow-up (P 0.05. Conclusion: Radiographic and clinical outcome in PRF group could suggest it as an acceptable alternative in pulpotomy of primary teeth. PRF holds a promising future in the area of primary tooth vital pulp therapy.

  3. Development of the first permanent mandibular molar in young children with unilateral complete cleft lip and palate (UCCLP)

    DEFF Research Database (Denmark)

    Hermann, Nuno Vibe; Darvann, Tron A; Kreiborg, Sven

    Development of the first permanent mandibular molar in young children with unilateral complete cleft lip and palate (UCCLP)......Development of the first permanent mandibular molar in young children with unilateral complete cleft lip and palate (UCCLP)...

  4. Evaluation of Root and Canal Systems of Mandibular First Molars in Taiwanese Individuals Using Cone-beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Chih-Chia Huang

    2010-04-01

    Conclusion: Our results showed a high overall incidence (32.6% of three-rooted mandibular first molars in Taiwanese individuals. CBCT could be a valuable tool for identifying an extra distolingual root in mandibular first molars.

  5. Elongational viscosity of narrow molar mass distribution polystyrene. A Bach, K. Almdal, H.K. Rasmussen and O. Hassager

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Bach, Anders; Almdal, Kristoffer

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distributin polystyrene melts ......Transient and steady elongational viscosity has been measured for two narrow molar mass distributin polystyrene melts ...

  6. Experience versus complication rate in third molar surgery

    Directory of Open Access Journals (Sweden)

    Al-Khawalde Mohammed

    2006-05-01

    Full Text Available Abstract Objectives The records of 1087 patients who underwent surgical removal of third molar teeth were prospectively examined to analyse the possible relationship between postoperative complications and the surgeon's experience parameter. Method and materials Seven surgeons (three specialists in surgical dentistry [specialists SD] and four oral and maxillofacial Senior House Officers [OMFS residents] carried out the surgical procedures. For each patient, several variables were recorded including age, gender, radiographic position of extracted teeth, treating surgeon, duration of surgery and postoperative complications. Results Analysis of the data revealed some differences in the incidence of complications produced by the specialists SD and OMFS residents. The main statistically relevant differences were increase the incidences of trismus, nerve paraesthesia, alveolar osteitis and infection in the resident-treated group, while the specialist-treated group showed higher rates of post-operative bleeding. Conclusion The higher rate of postoperative complications in the resident-treated group suggests that at least some of the complications might be related to surgical experience. Further work needs to compare specialists of training programmes with different years of experience, using large cross – sectional studies.

  7. Prevalence of molar incisor hypomineralization (MIH) in Singaporean children.

    Science.gov (United States)

    Ng, Jing Jing; Eu, Oy Chu; Nair, Rahul; Hong, Catherine Hsu Ling

    2015-03-01

    There is a lack of data on molar incisor hypomineralization (MIH) in Asia, but this is not an indication that MIH is rare in the Asian population. Early identification of MIH is important as affected teeth frequently display post-eruptive enamel loss which would result in rapid caries progression. This objective of this study was to assess the prevalence of MIH in Singaporean children. Patients were recruited from 30 schools across Singapore. All children were examined by a single dentist, and the judgement criteria used were based on the 2003 European Academy of Paediatric Dentistry criteria. A total of 1083 children; average age of 7.7 ± 0.3 years were examined. One hundred and thirty-five children (12.5%) had MIH. A significantly higher proportion of children of the Malay ethnicity had MIH, compared to Chinese children (P = 0.02). Post-eruptive enamel breakdown and the presence of atypical restorations were correlated with increasing number of MIH teeth/child (Rho= 0.599, P MIH occurrence and that MIH severity may be influenced by the number of MIH teeth/child and the cumulative enamel opacity colour score. © 2014 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Was molar incisor hypomineralisation (MIH) present in archaeological case series?

    Science.gov (United States)

    Kühnisch, Jan; Lauenstein, Anne; Pitchika, Vinay; McGlynn, George; Staskiewicz, Anja; Hickel, Reinhard; Grupe, Gisela

    2016-12-01

    With respect to the unknown aetiology of molar incisor hypomineralisation (MIH), it is unclear whether this phenomenon was overlooked in the last century as a result of a high number of caries in children or if this developmental disorder was not present until then. Therefore, this study determined the presence of MIH in historical dentitions and teeth. Dental remains from late medieval (n = 191, twelfth-sixteenth century, Regensburg, Germany), post-medieval (n = 33, sixteenth-eighteenth century, Passau, Germany) and modern age archaeological skeletal series (n = 99, nineteenth-twentieth century, Altdorf, Germany) were examined for MIH. In addition, linear enamel hypoplasia (LEH), diffuse opacities, hypoplasia and Turner's teeth were documented. MIH-related demarcated opacities or enamel breakdowns were found in only 15 (0.4 %) of the 3891 examined permanent teeth. Ten cases (3.1 %) from a total of 323 dentitions were classified as having MIH. In contrast, 98 individuals (30.3 %) showed LEH. Other enamel disorders were recorded in 64 individuals (19.8 %). With respect to the low number of affected dentitions and teeth, MIH most likely did not exist or was at least rarely present in the investigated archaeological case series. This study supports the hypothesis that MIH may be linked to contemporary living conditions or other health-related factors.

  9. Radiation absorbed doses at radiographic examination of third molars

    International Nuclear Information System (INIS)

    Rehnmark-Larsson, S.; Stenstroem, B.; Julin, P.; Richter, S.; Huddinge University Hospital

    1981-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. The greatest thyroid dose, 35 μGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. the corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50 %. The Ekta-Speed film requirted approximately 40 % lower exposure than the Ultra-Speed film. A horizontal radiation shield reduced the thyroid doses by between 12 and 46 % and the gonadal doses by between 50 and 95 %. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses between 15 and 42 % and the gonadal doses by two orders of magnitude. (Authors)

  10. Factors affecting root curvature of mandibular first molar

    International Nuclear Information System (INIS)

    Choi, Hang Moon; Yi, Won Jin; Heo, Min Suk; Kim, Jung Hwa; Choi, Soon Chul; Park, Tae Won

    2006-01-01

    To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Twenty six 1st graders whose mandibular 1st molars just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal place angle, gonial angle, and gonion-gnathion distance(Go-Gn distance) were measured. In panoramic radiograph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. The pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p 1 +0.745X 2 (Y: root angle, X 1 : variation of occlusal plane-tooth axis angle, X 2 : variation of ramus-occlusal plane angle). It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane

  11. Molar incisor hypomineralization in HIV-infected children and adolescents.

    Science.gov (United States)

    Andrade, Natália Silva; Pontes, Alessandra Silva; de Sousa Paz, Hélvis Enri; de Moura, Marcoeli Silva; Moura, Lúcia de Fátima Almeida de Deus; Lima, Marina de Deus Mourade

    2017-01-01

    The objective was to determine the prevalence of molar incisor hypomineralization (MIH) among individuals between 7 and 15 years old infected or noninfected with human immunodeficiency virus (HIV). The study was conducted with 33 HIV-infected individuals (study group; SG) and 66 non-HIV-infected schoolchildren (control group; CG), paired by gender and age. Data collection was based on medical records (SG), a questionnaire for caregivers and oral examination for diagnosis of MIH (European Academy of Pediatric Dentistry criteria) and caries (DMFT index and ICDAS). Data were analyzed with Mann-Whitney, chi-square, and Fisher's exact tests and logistic regression. In SG, MIH (45.5%) and caries (87.9%) had higher prevalence. MIH was associated with use of protease inhibitors in SG (OR: 2.14; 95% CI: 1.21 to 3.77) and incubator need in CG (OR: 2.80; 95% CI: 1.71 to 9.10). HIV-infected patients had a higher prevalence of MIH and dental caries in the permanent dentition. © 2016 Special Care Dentistry Association and Wiley Periodicals, Inc.

  12. La hiperdontia en región de molares

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    George Táccio de Miranda Candeiro

    2011-12-01

    Full Text Available La hiperdontia constituye una de las anomalías más estudiadas de la dentición humana. Esa alteración representa la aparición de uno o más dientes en cantidades mayores de lo normal, que puede ocurrir en la mandíbula o maxila y de manera unilateral o bilateral. La etiología de los dientes supernumerarios puede ser explicada principalmente por hiperactividad de la lámina dentaria en la fase inicial. Es importante la detección precoz de dientes supernumerarios porque se ha visto una serie de complicaciones como los diastemas, que pueden causar en la cavidad bucal: retardo de la erupción o dientes impactados, posicionamiento inadecuado de dientes permanentes, desajuste oclusal y el desarrollo de quistes y tumores odontógenos. Así el diagnóstico es normalmente realizado a partir de un examen radiográfico convencional, principalmente la radiografía panorámica. Este trabajo tuvo como objetivo relatar 4 casos clínicos de pacientes con presencia de molares supernumerarios, que fueron atendidos en el Servicio de Radiología de la Escuela de Odontología de la Universidad Federal de Ceará.

  13. Comparison Of Bond Strength Of Orthodontic Molar Tubes Using Different Enamel Etching Techniques And Their Effect On Enamel

    International Nuclear Information System (INIS)

    Abd el Rahman, H.Y.

    2013-01-01

    outer 10 micrometers on the enamel surface. The purpose of acid etching is to remove the smear layer and create an irregular surface by preferentially dissolving hydroxyapatite crystals on the outer surface. This topography will facilitate penetration of the fluid adhesive components into the irregularities. After polymerization, the adhesive is locked as proved by Dr. Bounocore into the surface and contributes to micromechanical retention. Sandblasting was introduced in orthodontics in an attempt to achieve proper etching for the enamel surface which would result in a better bond strength through aluminum oxide particles that are emitted from a specific hand piece at a high speed which produce roughness in enamel surfaces. Another method of increasing bond strength is by using an adhesion promoter. The expression 'adhesion promoter' was first used in connection with certain molecules which could achieve chemical bonding in dental structures. The word laser is an acronym for Light Amplification by Stimulated Emission of Radiation. The introduction of laser has revolutionized the bonding procedure. The first laser introduced was the helium-neon laser followed by Nd;YAG and CO 2 laser. Then the erbium family(Er;YAG and Er;Cr;YSSG) was introduced to dentistry. It has some advantages such as having no vibration or heat and producing a surface which is acid resistant by altering the calcium to phosphor ratio and formation of less soluble compounds. These characteristics make the erbium family more popular in orthodontics. If laser can achieve the above-mentioned function of acid etching, and even produce a favorable surface for bonding to a restorative material, it may be a viable alternative to acid etching. Although there are studies that have evaluated the effect of laser etching on bond strength, still further studies are needed for evaluating the shear bond strength of orthodontic molar tubes bonded to enamel prepared by the new Er;Cr;YSSG laser, sandblasting

  14. Comparison of clinical parameters and environmental noise levels between regular surgery and piezosurgery for extraction of impacted third molars

    OpenAIRE

    Chang, Hao-Hueng; Lee, Ming-Shu; Hsu, You-Chyun; Tsai, Shang-Jye; Lin, Chun-Pin

    2015-01-01

    Impacted third molars can be extracted by regular surgery or piezosurgery. The aim of this study was to compare clinical parameters and device-produced noise levels between regular surgery and piezosurgery for the extraction of impacted third molars. Methods: Twenty patients (18 women and 2 men, 17–29 years of age) with bilateral symmetrical impacted mandibular or maxillary third molars of the same level were included in this randomized crossover clinical trial. The 40 impacted third molar...

  15. Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments

    Directory of Open Access Journals (Sweden)

    Maryam Poosti

    2012-09-01

    Full Text Available Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction.

  16. Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments

    Directory of Open Access Journals (Sweden)

    Maryam Poosti

    2013-01-01

    Full Text Available Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction

  17. Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

    Science.gov (United States)

    Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

    2015-01-01

    SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698

  18. Restorasi Resin Komposit Menggunakan Pasak Tapered Self Threading Pada Molar Ketiga Kiri Mandibula

    Directory of Open Access Journals (Sweden)

    Ellen Krisanti

    2013-06-01

    Composite Resin Restoration Using Tapered Self Threading Poston Left Mandibular Third Molar. Root canal morphology of mandibular third molar has more complex variation than the other molars. In third molar, the extraction teeth are often executed; however, the third molar can be maintained in other conditions. One visit root canal treatment is a therapy option for this case. The purpose of this case report is to show the success of one visit root canal treatment in third molar with pulp necrosis by restoring the composite resin through tapered self-treading post. A 20 year-old female patient who came to the Prof Soedomo RSGM, FKG UGM complained about the pain when chewing food on her third molar and positive in percussion. The radiographs showed that there was an incomplete restoration. There was a gap between cavities with restoration. The treatment plan for this case was one visit root canal treatment and composite resin with tapered self-threading post as final restoration. From the case, it can concluded that one visit root canal treatment results in a smaller chance for microorganism recontamination than the multi-visit in order to ensure the success of the treatment. Direct composite resin restoration with tapered self-threading dowel is an alternative restoration after endodontic treatment because it works out faster and more retentive.

  19. Ectopic Molar Pregnancy: Diagnostic Efficacy of Magnetic Resonance Imaging and Review of the Literature.

    Science.gov (United States)

    Yamada, Yasushi; Ohira, Satoshi; Yamazaki, Teruyuki; Shiozawa, Tanri

    2016-01-01

    Ectopic molar pregnancy is extremely rare, and preoperative diagnosis is difficult. Our literature search found only one report of molar pregnancy diagnosed preoperatively. Moreover, there is no English literature depicting magnetic resonance image (MRI) findings of ectopic molar pregnancy. We report a case of ectopic molar pregnancy preoperatively diagnosed using MRI. A literature review of 31 cases of ectopic molar pregnancy demonstrated that lesions have been found in the fallopian tube (19 cases, 61%), ovary (5 cases, 16%), cornu (3 cases, 10%), peritoneum (2 cases, 6%), uterine cervix (1 case, 3%), and cesarean scar (1 case, 3%). Abdominal pain and abnormal vaginal bleeding were reported in 70% and 61% of the patients, respectively. Twenty-one cases (67%) presented with rupture and hemoperitoneum. All patients underwent surgical resection or dilatation and curettage. Methotrexate therapy was performed in one case because residual trophoblastic tissue was suspected. A second operation was performed in one case of ovarian molar pregnancy because serum hCG levels increased again after primary focal ovarian resection. No patients developed metastatic disease or relapsed. These findings suggest the prognosis of ectopic molar pregnancy to be favorable.

  20. Ectopic Molar Pregnancy: Diagnostic Efficacy of Magnetic Resonance Imaging and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Yasushi Yamada

    2016-01-01

    Full Text Available Ectopic molar pregnancy is extremely rare, and preoperative diagnosis is difficult. Our literature search found only one report of molar pregnancy diagnosed preoperatively. Moreover, there is no English literature depicting magnetic resonance image (MRI findings of ectopic molar pregnancy. We report a case of ectopic molar pregnancy preoperatively diagnosed using MRI. A literature review of 31 cases of ectopic molar pregnancy demonstrated that lesions have been found in the fallopian tube (19 cases, 61%, ovary (5 cases, 16%, cornu (3 cases, 10%, peritoneum (2 cases, 6%, uterine cervix (1 case, 3%, and cesarean scar (1 case, 3%. Abdominal pain and abnormal vaginal bleeding were reported in 70% and 61% of the patients, respectively. Twenty-one cases (67% presented with rupture and hemoperitoneum. All patients underwent surgical resection or dilatation and curettage. Methotrexate therapy was performed in one case because residual trophoblastic tissue was suspected. A second operation was performed in one case of ovarian molar pregnancy because serum hCG levels increased again after primary focal ovarian resection. No patients developed metastatic disease or relapsed. These findings suggest the prognosis of ectopic molar pregnancy to be favorable.

  1. Prevalence of radix entomolaris in mandibular permanent first molars: a study in a South Indian population.

    Science.gov (United States)

    Chandra, Saurabh S; Chandra, Supriya; Shankar, Padmanabhan; Indira, Rajamani

    2011-09-01

    Anatomical racial variations are an acknowledged characteristic in permanent molars. Generally, mandibular first molars have 2 roots; however, the presence of a third root, radix entomolaris (RE), is a major anatomic variant among many population groups. This study evaluated the prevalence of permanent mandibular first molars featuring a distolingual root in a South Indian population. Five hundred patients of South Indian origin possessing bilateral mandibular first molars were selected. The radiographs of these patients were evaluated under optimal conditions. A total of 1000 mandibular first molars were screened and the incidence of 3-rooted mandibular first molars and the correlation between left and right side occurrence and between either gender was recorded. The prevalence of 3-rooted mandibular first molars was 18.6% of the patients examined and 13.3% of the teeth examined. There was no statistically significant difference between genders or side of occurrence (P > .05). The bilateral incidence of a symmetric distribution was 43.01%. RE is considered an Asiatic trait. The occurrence of this macrostructure in the South Indian population was 13.3%, which was lower than that of other patients of Mongoloid origin. The clinician must thoroughly examine the radiograph before initiation of endodontic therapy. Copyright © 2011 Mosby, Inc. All rights reserved.

  2. Relationship between post-extraction pain and acute pulpitis: a randomised trial using third molars.

    Science.gov (United States)

    Zhang, Wei; Dai, Yong-Bo; Wan, Peng-Cheng; Xu, Dong-Dong; Guo, Yi; Li, Zhi

    2016-12-01

    The aim of the present study was to examine the relationship between post-extraction pain and acute pulpitis in third molars. This study was a randomised controlled trial. Sixty patients requiring removal of a single maxillary third molar with acute pulpitis were included and randomly divided into two groups: group A (n = 30); and group B (n = 30). In group A, third molars were directly extracted, and group B received endodontic therapy (pulp chamber opening and drainage) and underwent extraction 24 hours later, aiming to eliminate the acute inflammation. Another 30 patients requiring removal of a single maxillary third molar and with the same inclusion criteria but without caries or acute pulpitis were recruited into group C, in which the maxillary third molars were also directly extracted. The level of postoperative pain reported each day among the three groups was statistically evaluated. On the first, second and third days after surgery, there was a statistically significant difference between group A and group B and between group A and group C, but there was no statistically significant difference between group B and group C. The results of the present study indicate that there is more pain when third molars with acute pulpitis are directly removed compared with the pain level of the removal of third molars without acute pulpitis. © 2016 FDI World Dental Federation.

  3. Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars.

    Science.gov (United States)

    Abarca, J; Zaror, C; Monardes, H; Hermosilla, V; Muñoz, C; Cantin, M

    2014-06-01

    Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3-5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24-0.33 mm in maxillary first molars and between 0.25-0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully.

  4. Apparent molar volumes and compressibilities of electrolytes and ions in γ-butyrolactone

    International Nuclear Information System (INIS)

    Krakowiak, Joanna; Wawer, Jarosław; Farmas, Aleksander

    2012-01-01

    Highlights: ► Density and speed of sound for salts solutions in γ-butyrolactone were measured. ► The apparent molar volumes and compressibilities have been determined. ► The limiting molar quantities are split into independent ionic contributions. ► These data are used to describe ion–solvent interactions. - Abstract: The densities of tetraphenylphosphonium bromide, sodium tetraphenylborate, lithium perchlorate, sodium perchlorate and lithium bromide in γ-butyrolactone at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and speed of sound at 298.15 K have been measured. From these data apparent molar volumes V Φ at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and the apparent molar isentropic compressibility K S,Φ , at T = 298.15 K of the salts have been determined. The apparent molar volumes and the apparent molar isentropic compressibilities were fitted to the Redlich, Rosenfeld and Mayer equation as well as to the Pitzer and Masson equations yielding infinite dilution data. The obtained limiting values have been used to estimate the ionic data of the standard partial molar volume and the standard partial isentropic compressibility in γ-butyrolactone solutions.

  5. Third molars and periodontal pathology in American adolescents and young adults: a prevalence study.

    Science.gov (United States)

    Blakey, George H; Gelesko, Savannah; Marciani, Robert D; Haug, Richard H; Offenbacher, Steven; Phillips, Ceib; White, Raymond P

    2010-02-01

    To assess the association between visible third molars and the prevalence of periodontal inflammatory disease of non-third molars. Subjects aged 14 to 45 years with 4 asymptomatic third molars were enrolled in an institutional review board-approved study. Subjects were classified based on whether at least 1 third molar was visible or all third molars were not visible. Full-mouth periodontal probing depth (PD) data, with 6 sites per tooth, were obtained as a measure of a subject's periodontal status. At least 1 non-third molar PD of 4 mm or greater was indicative of periodontal inflammatory disease. Outcomes for the respective groups were compared by use of Cochran-Mantel-Haenszel row mean score statistics. The level of significance for differences was set at .05. The 342 subjects in the visible group were significantly older, with a median age of 26 years (interquartile range, 22.4-32.2 years), as compared with the 69 subjects in the not visible group, with a median age of 21 years (interquartile range, 18.8-24.9 years) (P .05). Most subjects were white. Significantly more subjects with at least a college education were in the visible group than in the not visible group (P adolescents and young adults was significantly associated with periodontal inflammatory disease of non-third molars. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography

    International Nuclear Information System (INIS)

    Choi, Mi Ree; Moon, Young Mi; Seo, Min Seock

    2015-01-01

    This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar

  7. Effect of Submucosal Injection of Dexamethasone on Post-operative Sequelae of Third Molar Surgery

    Directory of Open Access Journals (Sweden)

    S P Deo

    2011-06-01

    Full Text Available Introduction: This study was carried out to evaluate the effects of a single pre-operative sub-mucosal injection of dexamethasone after third molar surgery to see the effects on post-operative discomfort. Methods: This study was a prospective, double-blind, randomized, clinical trial. The subjects were forty patients who underwent surgical removal of the mandibular impacted third molar under local anesthesia and after being randomly assigned to receive either an 8 mg dexamethasone as submucosal injection or a normal saline injection into the lower buccal vestibule adjacent to the third molar. The maximum interincisal distance and facial contours were measured at the baseline and post-surgically on Day 2 and 7. Post-operative pain was evaluated subjectively using a visual analog scale and objectively by counting the number of analgesic tablets used. All subjects were operated upon by the same investigator to minimize the difference from inter-operator variability. Results: There was a signicant difference in the measurements of the degree of swelling and trismus between the two groups on the 2nd post-operative day. In contrast, there was no statistically signicant difference between the groups on the 7th post-operative day. The test group also used fewer analgesics post-operatively. Conclusions: Submucosal injection of dexamethasone after third molar surgery is effective in reducing postoperative swelling and trismus. It also delays the onset of post-operative pain. Keywords: dexamethasone, submucosal injection, third molar, third molar surgery, third molar extraction

  8. Radiographic correlation of dental and skeletal age: Third molar, an age indicator.

    Science.gov (United States)

    Suma, Gn; Rao, Balaji B; Annigeri, Rajeshwari G; Rao, Dayashankara Jk; Goel, Sumit

    2011-01-01

    Age estimation plays a great role in forensic investigations, orthodontic and surgical treatment planning, and tooth transplantation. Teeth offer an excellent material for age determination by stages of development below the age of 25 years and by secondary changes after the age of 25 years. Third molar is often not included for this purpose due to its notorious developmental patterns. The aim of this study was to evaluate the development of third molar anlage in relation to skeletal maturities and the chronological age. One hundred and fifty-six young individuals, 78 males and 78 females, were selected. The stages of development of all the third molars in every individual were determined from panoramic radiographs. The skeletal development was assessed using hand wrist radiographs. Data were analyzed statistically for mean value, standard deviation and the relationship between the recorded characteristics. A STRONG CORRELATION WAS FOUND BETWEEN THIRD MOLAR DEVELOPMENT AND SKELETAL MATURITY (IN MALES: r=0.88, Pthird molar and 0.89 for mandibular third molar, Page, developmental stages of third molars and maturation of epiphyses of hand. Any of the three parameters could be used for the assessment of other maturities.

  9. Morphometric variation of extant platyrrhine molars: taxonomic implications for fossil platyrrhines

    Directory of Open Access Journals (Sweden)

    Mónica Nova Delgado

    2016-05-01

    Full Text Available The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle Miocene stem platyrrhines lacking modern descendants, whereas the long lineage hypothesis argues for an evolutionary continuity of all fossil platyrrhines with the extant ones. Our geometric morphometric analysis of a 15 landmark-based configuration of platyrrhines’ first and second lower molars suggest that morphological stasis may explain the reduced molar shape variation observed. Platyrrhine lower molar shape might be a primitive retention of the ancestral state affected by strong ecological constraints throughout the radiation of the main platyrrhine families. The Patagonian fossil specimens showed two distinct morphological patterns of lower molars, Callicebus—like and Saguinus—like, which might be the precursors of the extant forms, whereas the Middle Miocene specimens, though showing morphological resemblances with the Patagonian fossils, also displayed new, derived molar patterns, Alouatta—like and Pitheciinae—like, thereby suggesting that despite the overall morphological stasis of molars, phenotypic diversification of molar shape was already settled during the Middle Miocene.

  10. Evaluation of the distortion rate of panoramic and peri apical radiographs in erupted third molar inclination

    International Nuclear Information System (INIS)

    Ezoddini Ardakani, F.; Zangouie Booshehri, M.; Behniafar, B.

    2011-01-01

    Panoramic and peri apical radiographs are normally used in impacted third molar teeth surgeries. The aim of the present study was to evaluate and compare the distortion of the erupted third molar teeth on panoramic and peri apical radiographs. Patients and Methods: A total of 44 radiographs were obtained of 22 patients (age range, 18-24 years) referred to the faculty of dentistry for orthodontic treatment. A plaster cast was prepared and panoramic radiography was taken for all patients to plan the orthodontic treatment and peri apical radiography was taken for investigation of tooth structure details. Therefore, a total of 66 views and samples were studied by two methods: 1) Measuring the angle between the longitudinal plane of the third molar and occlusal plane. 2) Measuring the angle between the longitudinal plane of second and third molar. Finally, 132 records were evaluated by one individual. Results: There was no significant statistical difference between the mean position of the third molar on panoramic, peri apical radiographs and the casts. However, measurements of the third molars on peri apical radiographs were slightly closer to the measurements of the casts compared to the panoramic radiographs. Conclusion: Distortion does not have a specific effect on the diagnosis of the position of the third erupted molars by peri apical or panoramic radiographs, though various studies have shown that these radiographs have an amount of distortion and peri apical radiographical distortion is less than that in panoramic radiography.

  11. A radiographic study of the mandibular third molar root development in different ethnic groups.

    Science.gov (United States)

    Liversidge, H M; Peariasamy, K; Folayan, M O; Adeniyi, A O; Ngom, P I; Mikami, Y; Shimada, Y; Kuroe, K; Tvete, I F; Kvaal, S I

    2017-12-01

    The nature of differences in the timing of tooth formation between ethnic groups is important when estimating age. To calculate age of transition of the mandibular third (M3) molar tooth stages from archived dental radiographs from sub-Saharan Africa, Malaysia, Japan and two groups from London UK (Whites and Bangladeshi). The number of radiographs was 4555 (2028 males, 2527 females) with an age range 10-25 years. The left M3 was staged into Moorrees stages. A probit model was fitted to calculate mean ages for transitions between stages for males and females and each ethnic group separately. The estimated age distributions given each M3 stage was calculated. To assess differences in timing of M3 between ethnic groups, three models were proposed: a separate model for each ethnic group, a joint model and a third model combining some aspects across groups. The best model fit was tested using Bayesian and Akaikes information criteria (BIC and AIC) and log likelihood ratio test. Differences in mean ages of M3 root stages were found between ethnic groups, however all groups showed large standard deviation values. The AIC and log likelihood ratio test indicated that a separate model for each ethnic group was best. Small differences were also noted between timing of M3 between males and females, with the exception of the Malaysian group. These findings suggests that features of a reference data set (wide age range and uniform age distribution) and a Bayesian statistical approach are more important than population specific convenience samples to estimate age of an individual using M3. Some group differences were evident in M3 timing, however, this has some impact on the confidence interval of estimated age in females and little impact in males because of the large variation in age.

  12. Internet use, online information seeking and knowledge among third molar patients attending public dental services.

    Science.gov (United States)

    Hanna, K; Sambrook, P; Armfield, J M; Brennan, D S

    2017-09-01

    While Australians are searching the internet for third molar (TM) information, the usefulness of online sources may be questioned due to quality variation. This study explored: (i) internet use, online information-seeking behaviour among TM patients attending public dental services; and (ii) whether patients' TM knowledge scores are associated with the level of internet use and eHealth Literacy Scale (eHEALS) scores. Baseline survey data from the 'Engaging Patients in Decision-Making' study were used. Variables included: sociodemographics, internet access status, online information-seeking behaviour, eHEALS, the Control Preferences Scale (CPS) and TM knowledge. Participants (N = 165) were mainly female (73.8%), aged 19-25 years (42.4%) and had 'secondary school or less' education (58.4%). A majority (N = 79, 52.7%) had sought online dental information which was associated with active decisional control preference (odds ratio = 3.1, P = 0.034) and higher educational attainment (odds ratio = 2.7, P = 0.040). TM knowledge scores were not associated with either the level of internet use (F (2,152) = 2.1, P = 0.094, χ 2 = 0.0310) or the eHEALS scores (r = 0.147, P = 0.335). 'The internet-prepared patient' phenomena exists among public TM patients and was explained by preference for involvement in decision-making. However, internet use was not associated with better TM knowledge. Providing TM patients with internet guidance may be an opportunity to improve TM knowledge. © 2017 Australian Dental Association.

  13. The Reference Return Ratio

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Faber Frandsen, Tove

    2008-01-01

    The paper introduces a new journal impact measure called The Reference Return Ratio (3R). Unlike the traditional Journal Impact Factor (JIF), which is based on calculations of publications and citations, the new measure is based on calculations of bibliographic investments (references) and returns...... (citations). A comparative study of the two measures shows a strong relationship between the 3R and the JIF. Yet, the 3R appears to correct for citation habits, citation dynamics, and composition of document types - problems that typically are raised against the JIF. In addition, contrary to traditional...

  14. Potential support ratios

    DEFF Research Database (Denmark)

    Kjærgaard, Søren; Canudas-Romo, Vladimir

    2017-01-01

    The ‘prospective potential support ratio’ has been proposed by researchers as a measure that accurately quantifies the burden of ageing, by identifying the fraction of a population that has passed a certain measure of longevity, for example, 17 years of life expectancy. Nevertheless......, the prospective potential support ratio usually focuses on the current mortality schedule, or period life expectancy. Instead, in this paper we look at the actual mortality experienced by cohorts in a population, using cohort life tables. We analyse differences between the two perspectives using mortality models...

  15. Radiographic assessment of third molars development and it's relation to dental and chronological age in an Iranian population.

    Science.gov (United States)

    Monirifard, Mohamad; Yaraghi, Navid; Vali, Ava; Vali, Asana; Vali, Amrita

    2015-01-01

    The aim of the present study was to estimate chronological age based on third molar development and to determine the association between dental age and third molar calcification stages. In this cross-sectional study, 505 digital panoramic radiographs of 223 males (44.2%) and 282 females (55.8%) between the age of 6 and 17 were selected from patients who were treated in Departments of Pediatrics and Orthodontics of Isfahan University of Medical Sciences between the years of 2009 and 2013. Correlation between chronological age and third molar development was analyzed with SPSS 21 using Spearman's Rank correlation coefficient, Chi-square test and multiple regression statistical tests (P third molars demonstrated a highly significant correlation with dental age (P age were mandibular left third molar in males and mandibular right third molar in females (r s = 0.072). When multiple regression was used to predict dental age based on molar calcification stage, the only significant correlation was between maxillary left third molar in males (P third molars in females. Relationship between chronological age and molars development stage was significant in all age subgroups and in both gender (P third molars and dental age in males. Results showed that third molar calcification stage can be used as an age predictor and in general mandibular teeth seems to be more reliable for this purpose in both genders and in all ages.

  16. Prevalence, association, and sexual dimorphism of Carabelli's molar and shovel incisor traits amongst Jordanian population.

    Science.gov (United States)

    Khraisat, A; Taha, Sahar T; Jung, R E; Hattar, S; Smadi, L; Al-Omari, I K; Jarbawi, M

    2007-09-01

    The correlation between dental morphological traits can be used as an indicator to show major ethnic differences. Therefore, this study investigated the prevalence of Carabelli's molar and shovel incisor traits and tested their association and sexual dimorphism in Jordanian population. Three hundred subjects of school children at their 10th grade and of 15.5-year as an average age were involved. Alginate impressions for the maxillary arch were taken, poured, and casts were then trimmed. The selected accurate casts were of 132 male- and 155 female-students. The examined morphologic traits were Carabelli's trait on the maxillary first and second molars and shovel-shaped incisors. The relationship between different traits was investigated by Nonparametric Correlation analysis and Independent Sample t test was used to test sexual dimorphism in trait expression. The prevalence of Carabelli's trait in maxillary first molar and shovel trait in maxillary central incisor was relatively high (65.0 % and 53.0 %, respectively). The prevalence of Carabelli's trait on maxillary second molars was 3.8 %. Nonparametric Correlations revealed a strongest positive correlation between Carabelli's trait on maxillary first molar and shovel trait in males (P = 0.005). Significant sexual dimorphism was only found in the prevalence of Carabelli's trait on maxillary first molar (P = 0.013) and shovel trait (P = 0.038). The Jordanian Population had comparatively high prevalence of Carabelli's molar and shovel incisor traits. There was a positive association between Carabelli's trait on maxillary first molar and shovel trait in males. Sexual dimorphism was evident in Carabelli's trait on maxillary first molar and shovel trait.

  17. Four osteotomy methods with piezosurgery to remove complicated mandibular third molars: a retrospective study.

    Science.gov (United States)

    Ge, Jing; Yang, Chi; Zheng, Jia-Wei; He, Dong-Mei; Zheng, Ling-Yan; Hu, Ying-Kai

    2014-11-01

    Piezosurgery has been used widely in oral and maxillofacial surgery, but there has been no report systematically describing an osteotomy method with piezosurgery for complicated mandibular third molar removal. The aim of this study was to introduce 4 osteotomy methods using piezosurgery and evaluate their effects. A retrospective study was conducted of patients with a complicated impacted mandibular third molar requiring extraction. The predictor variable was the extraction technique. Four osteotomy methods using piezosurgery were tested according to different impaction types: method 1 involved complete bone removal; method 2 involved segmental bone removal; method 3 involved bone removal combined with tooth splitting; and method 4 involved block bone removal. Outcome variables were success rate, operative time, major complications (including nerve injury, mandible fracture, severe hematoma, or severe edema), and serious pyogenic infection. Data were analyzed using descriptive statistics. The study was composed of 55 patients with 74 complicated impacted mandibular third molars. All impacted mandibular third molars were removed successfully. The average surgical time was 15 minutes (range, 8 to 26 minutes). Thirty-eight molars (51.4%) were extracted by method 1, 18 molars (24.3%) by method 2, 12 molars (16.2%) by method 3, and 6 molars (8.1%) by method 4. Two cases (2.7%) developed postoperative infections and recovered within 1 week using drainage and antibiotic administration. The 4 osteotomy methods with piezosurgery provide effective ways of removing complicated impacted mandibular third molars. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Developmental constraints revealed by co-variation within and among molar rows in two murine rodents.

    Science.gov (United States)

    Renaud, Sabrina; Pantalacci, Sophie; Quéré, Jean-Pierre; Laudet, Vincent; Auffray, Jean-Christophe

    2009-01-01

    Morphological integration corresponds to interdependency between characters that can arise from several causes. Proximal causes of integration include that different phenotypic features may share common genetic sets and/or interact during their development. Ultimate causes may be the prolonged effect of selection favoring integration of functionally interacting characters, achieved by the molding of these proximal causes. Strong and direct interactions among successive teeth of a molar row are predicted by genetic and developmental evidences. Functional constraints related to occlusion, however, should have selected more strongly for a morphological integration of occluding teeth and a corresponding evolution of the underlying developmental and genetic pathways. To investigate how these predictions match the patterns of phenotypic integration, we studied the co-variation among the six molars of the murine molar row, focusing on two populations of house mice (Mus musculus domesticus) and wood mice (Apodemus sylvaticus). The size and shape of the three upper and lower molars were quantified and compared. Our results evidenced similar patterns in both species, size being more integrated than shape among all the teeth, and both size and shape co-varying strongly between adjacent teeth, but also between occluding teeth. Strong co-variation within each molar row is in agreement with developmental models showing a cascade influence of the first molar on the subsequent molars. In contrast, the strong co-variation between molars of the occluding tooth rows confirms that functional constraints molded patterns of integration and probably the underlying developmental pathways despite the low level of direct developmental interactions occurring among molar rows. These patterns of co-variation are furthermore conserved between the house mouse and the wood mouse that diverged >10 Ma, suggesting that they may constitute long-running constraints to the diversification of the murine

  19. Tau hadronic branching ratios

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    From 64492 selected \\tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \\pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \\pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \\tau-\\mu universality in hadronic decays, g_\\tau/g_\\mu \\ = \\ 1.0013 \\ \\pm \\ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \\tau decay width: R_{\\tau ,V} \\ = \\ 1.788 \\ \\pm \\ 0.025 and R_{\\tau ,A} \\ = \\ 1.694 \\ \\pm \\ 0.027. The ratio (R_{\\tau ,V} - R_{\\tau ,A}) / (R_{\\tau ,V} + R_{\\tau ,A}), equal to (2.7 \\pm 1.3) \\ \\%, is a measure of the importance of Q...

  20. Hypohyperdontia: Agenesis of three third molars and mandibular centrals associated with midline supernumerary tooth in mandible

    Directory of Open Access Journals (Sweden)

    Sivakumar Nuvvula

    2010-01-01

    Full Text Available Agenesis of teeth in a patient who also presents with a supernumerary tooth is one of the rare numerical anomalies in human dentition. Agenesis of third molars was shown to be associated with other missing permanent teeth. A review of literature on hypodontia including third molar agenesis, hyperdontia and a concomitant presence of these two conditions which is termed as hypohyperdontia is presented along with a case showing agenesis of three third molars, both mandibular central incisors and a midline supernumerary tooth.

  1. A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization.

    Science.gov (United States)

    Ozkalayci, Nurhat; Yetmez, Mehmet

    2016-01-01

    The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth.

  2. A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization

    Directory of Open Access Journals (Sweden)

    Nurhat Ozkalayci

    2016-01-01

    Full Text Available The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth.

  3. Approximal morphology as predictor of approximal caries in primary molar teeth

    DEFF Research Database (Denmark)

    Cortes, A; Martignon, S; Qvist, V

    2018-01-01

    consent was given, participated. Upper and lower molar teeth of one randomly selected side received a 2-day temporarily separation. Bitewing radiographs and silicone impressions of interproximal area (IPA) were obtained. One-year procedures were repeated in 52 children (84%). The morphology of the distal...... surfaces of the first molar teeth and the mesial surfaces on the second molar teeth (n=208) was scored from the occlusal aspect on images from the baseline resin models resulting in four IPA variants: concave-concave; concave-convex; convex-concave, and convex-convex. Approximal caries on the surface...

  4. Two-rooted maxillary first molars with two canals: a case series.

    Science.gov (United States)

    Shakouie, Sahar; Mokhtari, Hadi; Ghasemi, Negin; Gholizadeh, Seddigheh

    2013-01-01

    Thorough understanding of the anatomic and internal morphology of a root canal system is absolutely essential for the success of endodontic treatment. Since permanent maxillary first molars have shown variation in internal anatomy, morphology, this tooth has been reviewed extensively. Presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. In this report, three cases are presented, which involve the root canal treatment of maxillary first molars with fusion of the two buccal roots.

  5. Standard molar enthalpies of formation of three N-benzoylthiocarbamic-O-alkylesters

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Schroeder, Bernd; Dietze, Frank; Beyer, Lothar

    2004-01-01

    The standard (p 0 =0.1 MPa) molar enthalpies of combustion in oxygen of three crystalline N-benzoylthiocarbamic-O-alkylesters, PhCONHCSOR, R=Et (Hbtcee), n-Bu (Hbtcbe), n-Hex (Hbtche), were measured at T=298.15 K by rotating bomb calorimetry. The standard molar enthalpies of sublimation of the three compounds were measured using Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the compounds in their crystalline and gaseous phases, respectively

  6. Pressure Dependence of Molar Volume near the Melting Point in Benzene

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pressure dependence of the molar volume was at constant temperatures close to the melting point in benzene. The molar volume of benzene was calculated using experimental data for the thermal expansivity for constant temperatures of 25℃, 28.5℃, 40℃, and 51℃ at various pressures for both the solid and liquid phases. The predictions are in good agreement with the observed volumes in both the solid and liquid phases of benzene. The predicted values of the molar volume for a constant temperature of 28.5℃ in the liquid phase of benzene agree well with experimental data in the literature.

  7. Low-tmperature Heat Capacities and Standard Molar Enthalpy of Formation of 4-Nitrobenzyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    MENG, Qingfen; TAN, Zhicheng; WANG, Xiaohuan; DONG, Yaping; LI, Wu; SHI, Quan

    2009-01-01

    Low-temperature heat capacities of 4-nitrobenzyl alcohol (4-NBA) have been measured by a high precision automated adiabatic calorimeter over the temperature range from 78 to 396 K. The melting temperature, the molar calculated in the range from 80 to 400 K at the interval of 5 K. The constant-volume energy and standard molar en- at T=298.15 K. The standard molar enthalpy of formation has been derived, ΔfHom(C7H7NO3, s)=-(206.49± namic quantities through a Hess thermochemical cycle.

  8. Endodontic therapy of a mandibular third molar with 5 canals: a case report.

    Science.gov (United States)

    Silberman, Adrian; Heilborn, Carlos; Cohenca, Nestor

    2009-06-01

    Endodontic treatment of third molars often becomes part of comprehensive treatment plans, as it represents a more conservative and less invasive approach than its therapeutic alternatives. The frequency of anatomic variations in mandibular molars, particularly root canal configuration, requires 2 periapical radiographs from different angles. Upon reading and interpretation of the radiographs, the clinician should consider the anatomy and level of difficulty of the endodontic procedure and refer the patient to an endodontist, if deemed necessary. The present article discusses the successful treatment and preservation of a mandibular third molar with 5 root canals, as well as methods for its clinical management.

  9. Apparent molar volumes and compressibilities of alkaline earth metal ions in methanol and dimethylsulfoxide

    International Nuclear Information System (INIS)

    Warminska, Dorota; Wawer, Jaroslaw; Grzybkowski, Waclaw

    2010-01-01

    Temperature dependencies of density of magnesium (II), calcium (II), strontium (II), barium (II) perchlorates as well as beryllium (II), and sodium trifluoromethanesulfonates in methanol and dimethylsulfoxide have been determined over the composition range studied. From density data the apparent molar volumes and partial molar volumes of the salts at infinite dilution as well as the expansibilities have been evaluated. The apparent molar isentropic compressibilities of alkaline earth metal perchlorates and beryllium (II) and sodium triflates in methanol and DMSO have been calculated from sound speed data obtained at T = 298.15 K.

  10. Thermodynamic interrelation between excess limiting partial molar characteristics of a liquid nonelectrolyte

    International Nuclear Information System (INIS)

    Ivanov, Evgeniy V.

    2012-01-01

    Highlights: ► Excess limiting molar volume may be regarded as a solvation-related characteristic. ► Volumetric and enthalpic effects of dissolution are interrelated thermodynamically. ► Possibility to estimate the partial change in solute compressibility is described. - Abstract: On the basis of thermodynamic analysis, it is concluded that the excess limiting partial molar volume, like the excess limiting partial molar enthalpy, can be considered as a solvation-related characteristic of a liquid nonelectrolyte. A thermodynamically grounded interrelation between standard volumetric and enthalpic effects of solution of a liquid nonelectrolyte (or series of nonelectrolytes) is suggested.

  11. Unusual facial pain secondary to inferior alveolar nerve compression caused by impacted mandibular second molar

    Directory of Open Access Journals (Sweden)

    Urvashi Sharma

    2014-01-01

    Full Text Available Symptoms of inferior alveolar nerve (IAN compression are reported during endodontic procedures, placement of implants, third molar surgeries, inferior alveolar nerve block injections, trauma, orthognathic injuries, ablative surgeries or use of medicaments. Presented is a rare case of a 15-year-old girl who reported severe pain in relation to an impacted permanent mandibular left second molar, the roots of which had entrapped the mandibular canal causing compression of IAN. Timely surgical intervention and sectional removal of the impacted molar is indicated to relieve the symptoms and avoid permanent damage to the nerve.

  12. Effectiveness of various sterilization methods of contaminated post-fitted molar band

    Directory of Open Access Journals (Sweden)

    Anggia Tridianti

    2013-06-01

    Full Text Available Background: Molar band as anchoring device may be contaminated during the fitting process. Thus, decontamination process is essential to prevent cross-infection between patients. Purpose: The objective of this research was to determine the amount of bacteria in molar band post-fitted on the patient teeth, after previously undergone pre-sterilization using alcohol and ultrasonic cleaning bath followed by sterilization using dry heat oven and steam autoclave, in order to find the best method in decontamination of post-fitted molar band. Methods: Four molar bands which already fitted on one patient then divided evenly into two groups. The first group was pre-sterilized using alcohol. One of the bands then sterilized using dry heat oven, while the other one was sterilized using steam autoclave. The second group was pre-sterilized using ultrasonic cleaning bath. One band from this group then sterilized using dry heat oven and the other was sterilized using steam autoclave. The next step was to immerse all the bands in a phosphate-buffered saline solution. Using micropipette, the solution was retrieved and dropped upon a petri dish containing Brain Heart Infusion broth. The dish was then stored in an incubator for 24 hours, prior to counting the number of bacteria existed. The same methods were used to the rest of the patients, with total 128 molar bands from 32 patients. Results: There was a profound difference in numbers of bacteria found between those methods of sterilization. However, there was a non significant difference between the two groups which were at the alcohol-steam autoclave group and at the ultrasonic cleaning bath-steam autoclave group. Conclusion: This study showed that steam autoclave is better than for sterilizing molar band, as it left the minimal amount of bacteria in post-fitted molar band.Latar belakang: Molar band merupakan suatu alat penjangkaran yang dapat mengalami kontaminasi selama proses fitting band, sehingga perlu

  13. Effects of ionizing radiation on wound healing of alveolar bone socket after extraction of rat maxillary molars

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Hiroshi; Yosue, Takashi [Nippon Dental Univ., Tokyo (Japan). School of Dentistry; Nasu, Masanori

    2001-05-01

    The purpose of this study was to examine the effects of radiation on the healing process of tooth extraction wounds. X-ray doses of 10 Gy or 20 Gy were delivered, once, to the maxillofacial area of Wistar-strain rats. Then, 24 hours after irradiation, the maxillary first molars were extracted bilaterally. The animals were sacrificed 3, 7, 10, 14, 21, 42, and 84 days after tooth extraction, and the maxilla were sliced, to make thin sections. These specimens were then double stained with alkaline phosphatase (ALP) and tartrate resistant acid phosphatase (TRAP). The ratio of bone area to socket area (bone formation ratio), the ratio of bone length to ALP positive area length (ALP positive ratio), and the number of TRAP-positive cells, were evaluated. The results showed: The bone formation ratios at days 3 and 7 after tooth extraction were significantly low in both irradiation groups, compared with those for the non-irradiation group. The ALP positive reaction ratio peaked 7 days after in the non-irradiation group. In both irradiation groups, the ratios that were worked out at 3 days and 7 days after were significantly lower than those in the non-irradiation group. There was no significant difference in the number of TRAP-positive cells between the non-irradiation group and the 10 Gy irradiation group. In the 20 Gy irradiation group, the TRAP-positive cell count plummeted to a significantly low level at 3 days after tooth extraction, compared with that in the non-irradiation group. (author)

  14. Effects of ionizing radiation on wound healing of alveolar bone socket after extraction of rat maxillary molars

    International Nuclear Information System (INIS)

    Iwata, Hiroshi; Yosue, Takashi; Nasu, Masanori

    2001-01-01

    The purpose of this study was to examine the effects of radiation on the healing process of tooth extraction wounds. X-ray doses of 10 Gy or 20 Gy were delivered, once, to the maxillofacial area of Wistar-strain rats. Then, 24 hours after irradiation, the maxillary first molars were extracted bilaterally. The animals were sacrificed 3, 7, 10, 14, 21, 42, and 84 days after tooth extraction, and the maxilla were sliced, to make thin sections. These specimens were then double stained with alkaline phosphatase (ALP) and tartrate resistant acid phosphatase (TRAP). The ratio of bone area to socket area (bone formation ratio), the ratio of bone length to ALP positive area length (ALP positive ratio), and the number of TRAP-positive cells, were evaluated. The results showed: The bone formation ratios at days 3 and 7 after tooth extraction were significantly low in both irradiation groups, compared with those for the non-irradiation group. The ALP positive reaction ratio peaked 7 days after in the non-irradiation group. In both irradiation groups, the ratios that were worked out at 3 days and 7 days after were significantly lower than those in the non-irradiation group. There was no significant difference in the number of TRAP-positive cells between the non-irradiation group and the 10 Gy irradiation group. In the 20 Gy irradiation group, the TRAP-positive cell count plummeted to a significantly low level at 3 days after tooth extraction, compared with that in the non-irradiation group. (author)

  15. Pulpal responses to cavity preparation in aged rat molars.

    Science.gov (United States)

    Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato

    2006-10-01

    The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, few data are available concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense in aged pulp by investigating the responses of odontoblasts and cells positive for class II major histocompatibility complex (MHC) to cavity preparation in aged rat molars (300-360 days) and by comparing the results with those in young adult rats (100 days). In untreated control teeth, immunoreactivity for intense heat-shock protein (HSP)-25 and nestin was found in odontoblasts, whereas class-II-MHC-positive cells were densely distributed in the periphery of the pulp. Cavity preparation caused two types of pulpal reactions based on the different extent of damage in the aged rats. In the case of severe damage, destruction of the odontoblast layer was conspicuous at the affected site. By 12 h after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border but subsequently disappeared together with HSP-25-immunopositive cells, and finally newly differentiated odontoblast-like cells took the place of the degenerated odontoblasts and acquired immunoreactivity for HSP-25 and nestin by postoperative day 3. In the case of mild damage, no remarkable changes occurred in odontoblasts after operation, and some survived through the experimental stages. These findings indicate that aged pulp tissue still possesses a defense capacity, and that a variety of reactions can occur depending on the difference in the status of dentinal tubules and/or odontoblast processes in individuals.

  16. Third molar surgery: the patient's and the clinician's perspective

    Directory of Open Access Journals (Sweden)

    Jerjes Waseem

    2009-10-01

    Full Text Available Abstract Background In this report, the problems of third molar surgery have been reviewed from the perspective of both patient and clinician; additionally an overall analysis of preoperative imaging investigations was carried out. Specifically, three main areas of interest were investigated: the prediction of surgical difficulty and potential complications; the assessment of stress and anxiety and finally the assessment of postoperative complications and the surgeon's experience. Findings In the first study, the prediction of surgical difficulty and potential injury to the inferior alveolar nerve was assessed. This was achieved by examining the patient's orthopantomograms and by using the Pederson Difficulty Index (PDI. Several radiological signs were identified and a classification tree was created to help predict the incidence of such event. In the second study, a prospective assessment addressing the patient's stress and anxiety pre-, intra- and postoperatively was employed. Midazolam was the active drug used against placebo. Objective and subjective parameters were assessed, including measuring the cortisol level in saliva. Midazolam was found to significantly reduce anxiety levels and salivary cortisol was identified as an accurate anxiety marker. In the third study, postoperative complications and the surgeon's experience were examined. Few patients in this study suffered permanent nerve dysfunction. Junior surgeons reported a higher complication rate particularly in trismus, alveolar osteitis, infection and paraesthesia over the distributions of the inferior alveolar and lingual nerves. In apparent contrast, senior surgeons reported higher incidence of postoperative bleeding. Discussion These studies if well employed can lead to favourable alteration in patient management and might have a positive impact on future healthcare service.

  17. Peak power ratio generator

    Science.gov (United States)

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  18. Actitud terapéutica ante sacos foliculares de terceros molares incluídos Therapeutic approach to impacted third molar follicles

    Directory of Open Access Journals (Sweden)

    R. González García

    2005-04-01

    Full Text Available El quiste dentígero o folicular es un quiste odontogénico del desarrollo. Está revestido por el epitelio del folículo dentario, y suele estar en relación con un diente permanente incluído. Presentamos el caso clínico de un paciente en el que se observa la aparición de un quiste dentígero a partir del saco folicular de un tercer molar incluído no exodonciado, y lo comparamos con la evolución de un cordal incluído y su saco folicular contralaterales en los que se realizó la exodoncia. El tratamiento definitivo del quiste dentígero asociado a un tercer molar incluído es quirúrgico, con la exodoncia de la pieza y enucleación del quiste. Los sacos foliculares mayores de 2 mm asociados a terceros molares incluídos evolucionan en numerosas ocasiones a quistes foliculares. Está indicada la exodoncia de dichos cordales para evitar la evolución a quiste dentígero.The dentigerous cyst or follicular cyst is a developmental odontogenic cyst. It is covered by the epithelium of the dental follicle, and it tends to be related to an impacted permanent tooth. The case report of a patient who was seen to develop a dentigerous cyst arising from the follicle of an impacted non-extracted third molar is presented. This is then compared with the evolution of the contralateral impacted third molar and its follicle that was extracted. The definitive treatment for a dentigerous cyst associated with an impacted third molar is surgical, the extraction of the tooth and enucleation of the cyst. Follicles measuring more+ than 2 mm and that are associated with impacted third molars often develop into follicular cysts. The extraction of these third molars is indicated in order to avoid the development of a dentigerous cyst

  19. Avaliação da anatomia de molares decíduos por meio de microtomografia computadorizada

    OpenAIRE

    Ana Caroline Fumes

    2013-01-01

    O conhecimento prévio da anatomia interna e externa dos dentes decíduos é de fundamental importância para o sucesso do tratamento endodôntico. O objetivo do presente estudo foi analisar a morfologia das raízes e dos canais radiculares de molares decíduos superiores e inferiores, por meio de microtomografia computadorizada (micro-CT). Foram usados 40 molares decíduos, divididos em quatro grupos, sendo 10 primeiros molares inferiores, 10 segundos molares inferiores, 10 primeiros molares superio...

  20. Molar-incisor-hypomineralisation (MIH). Retrospective clinical study in Greek children. I. Prevalence and defect characteristics.

    Science.gov (United States)

    Lygidakis, N A; Dimou, G; Briseniou, E

    2008-12-01

    This was to evaluate the prevalence and the clinical characteristics of MIH in a group of Greek children. During the years 2003--2005, all MIH cases diagnosed according to the recently set criteria were selected from the new patients clinic of a Community Dental Centre for Children (Athens). Age, gender and teeth involved were recorded. The severity of MIH was determined collectively by dividing the affected teeth in two groups; a) mild defect (demarcated opacities) and b) moderate/severe defect (enamel breakdown and atypical restorations). Evaluation of the distribution of the affected teeth within MIH cases was performed in a separate group of 225 affected children aged 8-12 years with their entire 12 'index' teeth erupted. From the 3,518, 5.5 to 12 year old children that were examined, there were 360 (10.2%) children with MIH, 211 (58.6%) females and 149 (41.4%) males, with 1,926 affected teeth, 1,231 molars and 695 incisors. In the molars group, maxillary molars were more frequently affected (87.8/90.3%) than mandibular (81.7/82.2%). In the central incisor group, maxillary teeth were also more frequently affected (50/55%) than mandibular (24.4/25%), while laterals were the least affected. In all there were 37.9% molars with moderate/severe defects as compared with 4.9% incisors, the remaining 62.1% and 95.1% respectively being mild. The various associations between the affected teeth were evaluated in the sub-group of 225 MIH children with all 'index' teeth erupted (1,286 affected teeth, 776 molars and 510 incisors), with mean number of affected teeth per child being 5.7; separately for molars 3.4 and for incisors 2.2. In these cases 28.4% of the children had only molars affected and 71.6% had both molars and incisors. In descending order the associations of affected teeth more frequently found were: 4 molars/2 incisors (23.5%), 4 molars/4 incisors (16.8%), 4 molars alone (15.1%) and 2 molars alone (9.7%), the remaining being much less. As age increased the