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1.
Polymers (Basel) ; 14(6)2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35335499

RESUMO

Additive Manufacturing (AM) offers remarkable advantages in relation to traditional methods used to obtain solid structures, such as the capability to obtain customized complex geometries adapted to individual requirements. The design of novel nanocomposites suitable for AM is an excellent strategy to widen the application field of these techniques. In this work, we report on the fabrication of metal/polymer nanocomposites with enhanced optical/electrical behaviour for stereolithography (SLA). In particular, we analyse the in situ generation of Ag nanoparticles (NPs) from Ag precursors (AgNO3 and AgClO4) within acrylic resins via SLA. Transmission electron microscopy (TEM) analysis confirmed the formation of Ag NPs smaller than 5 nm in all nanocomposites, providing optical activity to the materials. A high density of Ag NPs with a good distribution through the material for the larger concentration of AgClO4 precursor tested was observed, in contrast to the isolated agglomerations found when the precursor amount was reduced to 0.1%. A significant reduction in the electrical resistivity up to four orders of magnitude was found for this material compared to the unfilled resin. However, consumption of part of the photoinitiator in the formation process of the Ag NPs contributed to a reduction in the polymerization degree of the resin and, consequently, degraded the mechanical properties of the nanocomposites. Experiments with longer curing times showed that, for the higher AgClO4 concentrations tested, post-curing times of 300 min allowed an 80% degree of polymerization to be achieved. These conditions turned these materials into promising candidates to obtain solid structures with multifunctional properties.

2.
Nanoscale ; 11(46): 22378-22386, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31730145

RESUMO

Photonic applications based on halide perovskites, namely CH3NH3PbI3 (MAPbI3), have recently attracted remarkable attention due to the high efficiencies reported for photovoltaic and light emitting devices. Despite these outstanding results, there are many temperature-, laser excitation power-, and morphology-dependent phenomena that require further research to be completely understood. In this work, we have investigated in detail the nature of exciton optical transitions and recombination dynamics below and above the orthorhombic/tetragonal ('O'-/'T'-) temperature phase transition (∼150 K) depending on the material continuity (continuous-like) or discontinuity (island-like) in MAPbI3 films. At low temperatures, continuous thin films of the perovskite can exhibit strain inhomogeneities associated with the formation of different 'T'-defective domains leading to an energy spread of states over more than 200 meV. On the other hand, a single photoluminescence line peak related to the perovskite 'O'-phase (associated with the distortion of the [PbI3]- anion) is observed in the island-like sample that we attribute to strain relaxation for this morphology. Moreover, the predominantly radiative recombination dynamics of the continuous-like sample mainly originates from nongeminate electron-hole formation of excitons in the 'O'-phase and the internal dynamics with carrier trapping levels. This observation is in strong contrast to the free exciton recombination dominantly found in the island-like sample.

3.
Sci Rep ; 9(1): 8950, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222059

RESUMO

Whilst the different forms of conventional (charge-based) memories are well suited to their individual roles in computers and other electronic devices, flaws in their properties mean that intensive research into alternative, or emerging, memories continues. In particular, the goal of simultaneously achieving the contradictory requirements of non-volatility and fast, low-voltage (low-energy) switching has proved challenging. Here, we report an oxide-free, floating-gate memory cell based on III-V semiconductor heterostructures with a junctionless channel and non-destructive read of the stored data. Non-volatile data retention of at least 104 s in combination with switching at ≤2.6 V is achieved by use of the extraordinary 2.1 eV conduction band offsets of InAs/AlSb and a triple-barrier resonant tunnelling structure. The combination of low-voltage operation and small capacitance implies intrinsic switching energy per unit area that is 100 and 1000 times smaller than dynamic random access memory and Flash respectively. The device may thus be considered as a new emerging memory with considerable potential.

4.
Artigo em Inglês | MEDLINE | ID: mdl-28800094

RESUMO

OBJECTIVE: To determine the frequency and associated factors of visits to the dentist in the last year by Nicaraguan schoolchildren to receive professionally applied topical fluoride (PATF). MATERIAL AND METHODS: A cross-sectional study was designed in children from public schools in the city of León, Nicaragua, were included. A series of socioeconomic, sociodemographic, and behavioural variables were collected through a questionnaire. The dependent variable was the visit to the dentist to receive professionally applied topical fluoride in the last year, which was dichotomised as (0) Did not receive PATF and (1) Yes received PATF. In the statistical analysis, binary logistic regression was used. RESULTS: The mean age of the students included was 9 years, and 49.9% were girls. The prevalence of visits to the dentist in the last year to receive PATF was 3.1%. In the multivariate model, the associated characteristics (p < 0.05) were: female (OR = 2.73, 95% CI = 1.34-4.50); the positive attitude of the mother to the oral health of her child (OR = 2.15, 95% CI = 1.03-4.50); and the best socioeconomic position (OR = 2.68, 95% CI = 1.36-5.31). CONCLUSIONS: The prevalence of visits to the dentist in the last year to receive professionally applied topical fluoride was very low (3.1%). The results of the socioeconomic position suggest the existence of certain inequalities in oral health. It is necessary to implement policies and programs aimed at improving this scenario.


Assuntos
Países em Desenvolvimento , Fluoretos Tópicos , Fatores Socioeconômicos , Criança , Estudos Transversais , Assistência Odontológica , Feminino , Humanos , Modelos Logísticos , Masculino , Nicarágua , Instituições Acadêmicas , Estudantes , Inquéritos e Questionários
5.
Nanotechnology ; 26(40): 405702, 2015 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-26377736

RESUMO

We present the mapping of the plasmonic properties of gold nanoparticles that are embedded in a TiO2 thin film deposited over two different substrates, glass and silicon. An improved electron energy-loss spectroscopy (EELS) imaging technique was used to extract plasmon maps with nanometre resolution. Several representative cases of randomly dispersed NPs have been examined to carefully evaluate surrounding effects on the optical response of such nanostructured material. Data were compared to analytical calculations and showed good agreement. These results validate previous structural and far-field optical results and provide a clear description of the optical phenomena that take place at a nanometre scale in these materials. They are of primary importance for enlightening the way to the fabrication of thin film materials including metallic nanostructures for photovoltaic applications.

6.
Ultramicroscopy ; 146: 33-8, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24929924

RESUMO

In this work we examined MoS2 sheets by aberration-corrected scanning transmission electron microscopy (STEM) at three different energies: 80, 120 and 200 kV. Structural damage of the MoS2 sheets has been controlled at 80 kV according a theoretical calculation based on the inelastic scattering of the electrons involved in the interaction electron-matter. The threshold energy for the MoS2 material has been found and experimentally verified in the microscope. At energies higher than the energy threshold we show surface and edge defects produced by the electron beam irradiation. Quantitative analysis at atomic level in the images obtained at 80 kV has been performed using the experimental images and via STEM simulations using SICSTEM software to determine the exact number of MoS22 layers.

7.
Nanoscale Res Lett ; 8(1): 513, 2013 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-24308663

RESUMO

The finite elements method (FEM) is a useful tool for the analysis of the strain state of semiconductor heterostructures. It has been used for the prediction of the nucleation sites of stacked quantum dots (QDs), but often using either simulated data of the atom positions or two-dimensional experimental data, in such a way that it is difficult to assess the validity of the predictions. In this work, we assess the validity of the FEM method for the prediction of stacked QD nucleation sites using three-dimensional experimental data obtained by atom probe tomography (APT). This also allows us to compare the simulation results with the one obtained experimentally. Our analysis demonstrates that FEM and APT constitute a good combination to resolve strain-stress problems of epitaxial semiconductor structures.

8.
Med Sci Monit ; 19: 1019-26, 2013 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-24247119

RESUMO

BACKGROUND: Our study aimed to evaluate the effect of various risk indicators for dental caries on primary teeth of Nicaraguan children (from Leon, Nicaragua) ages 6 to 9, using the negative binomial regression model. MATERIAL/METHODS: A cross-sectional study was carried out to collect clinical, demographic, socioeconomic, and behavioral data from 794 schoolchildren ages 6 to 9 years, randomly selected from 25 schools in the city of León, Nicaragua. Clinical examinations for dental caries (dmft index) were performed by 2 trained and standardized examiners. Socio-demographic, socioeconomic, and behavioral data were self-reported using questionnaires. Multivariate negative binomial regression (NBR) analysis was used. RESULTS: Mean age was 7.49 ± 1.12 years. Boys accounted for 50.1% of the sample. Mean dmft was 3.54 ± 3.13 and caries prevalence (dmft >0) was 77.6%. In the NBR multivariate model (p<0.05), for each year of age, the expected mean dmft decreased by 7.5%. Brushing teeth at least once a day and having received preventive dental care in the last year before data collection were associated with declines in the expected mean dmft by 19.5% and 69.6%, respectively. Presence of dental plaque increased the expected mean dmft by 395.5%. CONCLUSIONS: The proportion of students with caries in this sample was high. We found associations between dental caries in the primary dentition and dental plaque, brushing teeth at least once a day, and having received preventive dental care. To improve oral health, school programs and/or age-appropriate interventions need to be developed based on the specific profile of caries experience and the associated risk indicators.


Assuntos
Cárie Dentária/epidemiologia , Cárie Dentária/prevenção & controle , Placa Dentária/patologia , Dente Decíduo/patologia , Escovação Dentária/estatística & dados numéricos , Criança , Estudos Transversais , Cárie Dentária/etiologia , Cárie Dentária/patologia , Placa Dentária/complicações , Feminino , Humanos , Masculino , Nicarágua/epidemiologia , Análise de Regressão , Fatores de Risco , Fatores Socioeconômicos , Inquéritos e Questionários
9.
Nanoscale Res Lett ; 7(1): 681, 2012 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-23249477

RESUMO

The 3D distribution of self-assembled stacked quantum dots (QDs) is a key parameter to obtain the highest performance in a variety of optoelectronic devices. In this work, we have measured this distribution in 3D using a combined procedure of needle-shaped specimen preparation and electron tomography. We show that conventional 2D measurements of the distribution of QDs are not reliable, and only 3D analysis allows an accurate correlation between the growth design and the structural characteristics.

11.
Microsc Microanal ; 17(4): 578-81, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21615979

RESUMO

We show in this article that it is possible to obtain elemental compositional maps and profiles with atomic-column resolution across an InxGa1-xAs multilayer structure from 5th-order aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The compositional profiles obtained from the analysis of HAADF-STEM images describe accurately the distribution of In in the studied multilayer in good agreement with Muraki's segregation model [Muraki, K., Fukatsu, S., Shiraki, Y. & Ito, R. (1992). Surface segregation of In atoms during molecular beam epitaxy and its influence on the energy levels in InGaAs/GaAs quantums wells. Appl Phys Lett 61, 557-559].

12.
J Nanosci Nanotechnol ; 10(8): 5202-6, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21125871

RESUMO

Multilayer stacks of quantum dots (QDs) (10 periods) with a combination barrier layer of In0.21Al0.21 Ga0.58As (30 angstroms) and GaAs (70-180 angstroms) are grown by solid source molecular beam epitaxy (MBE) and reflection high-energy electron diffraction (RHEED) has been used for the in situ determination of the duration of dot formation in the QD layers. The increase in the duration of dot formation in the consecutive layers of the QD heterostructure with thinner barrier is attributed to the indium migration towards the defects in the strained QD layers. A thicker GaAs layer at 590 degrees C overgrown on the InAlGaAs is believed to remove the unevenness of the growth front for the subsequent QD layer resulting in good vertical stacking of islands till the final layer of the multilayer heterostructures.

13.
Rev Invest Clin ; 61(6): 489-96, 2009.
Artigo em Espanhol | MEDLINE | ID: mdl-20184130

RESUMO

OBJECTIVE: To identify the association between tooth brushing frequency and variables of socioeconomic position in Nicaraguan schoolchildren. MATERIAL AND METHODS: A cross sectional study was undertaken in 1353 schoolchildren ages 6 to 12 randomly selected from 25 elementary schools in Leon, Nicaragua. Using a questionnaire addressed to mothers, sociodemographic, socioeconomic and behavioral variables were collected. The dependent variable was tooth brushing frequency, which was dichotomized in 0 "at least one 7 times/week" and 1 "7 or more times/week". A multivariate analysis was carried out with logistic regression in STATA 9. RESULTS: The average age of child participants was 8.99 +/- 2.00 years and 49.7% were women. In the final model, older age (OR = 2.04), female sex (OR = 1.39) and having a mother with positive attitudes toward oral health (OR = 2.5) were positively associated with the tooth brushing frequency (p < 0.05). Larger family size (OR = 0.89) and having low socioeconomic status (1st quartile; OR = 0.54, 2nd quartile; OR = 0.62, 3rd quartile; OR = 0.67) showed a negative relationship with the tooth brushing frequency. To have had at least one preventive dental visit in the previous year was positively associated (p < 0.10) with tooth brushing frequency. CONCLUSION: This study suggested that existence of indicators of socioeconomic inequalities exist even within less developed countries, and thus emphasize the need to target health promotion programs to vulnerable socioeconomic groups.


Assuntos
Disparidades nos Níveis de Saúde , Saúde Bucal , Escovação Dentária/estatística & dados numéricos , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Nicarágua , Fatores Socioeconômicos
14.
J Public Health Dent ; 68(1): 39-45, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18179470

RESUMO

OBJECTIVE: To determine the factors associated with the dental health services utilization among children ages 6 to 12 in León, Nicaragua. MATERIAL AND METHODS: A cross-sectional study was carried out in 1,400 schoolchildren. Using a questionnaire, we determined information related to utilization and independent variables in the previous year. Oral health needs were established by means of a dental examination. To identify the independent variables associated with dental health services utilization, two types of multivariate regression models were used, according to the measurement scale of the outcome variable: a) frequency of utilization as (0) none, (1) one, and (2) two or more, analyzed with the ordered logistic regression and b) the type of service utilized as (0) none, (1) preventive services, (2) curative services, and (3) both services, analyzed with the multinomial logistic regression. RESULTS: The proportion of children who received at least one dental service in the 12 months prior to the study was 27.7 percent. The variables associated with utilization in the two models were older age, female sex, more frequent toothbrushing, positive attitude of the mother toward the child's oral health, higher socioeconomic level, and higher oral health needs. CONCLUSION: Various predisposing, enabling, and oral health needs variables were associated with higher dental health services utilization. As in prior reports elsewhere, these results from Nicaragua confirmed that utilization inequalities exist between socioeconomic groups. The multinomial logistic regression model evidenced the association of different variables depending on the type of service used.


Assuntos
Serviços de Saúde Bucal/estatística & dados numéricos , Países em Desenvolvimento , Criança , Estudos Transversais , Demografia , Feminino , Humanos , Renda , Modelos Logísticos , Masculino , Nicarágua , Análise de Componente Principal , Fatores Socioeconômicos
15.
Gac Sanit ; 19(4): 302-6, 2005.
Artigo em Espanhol | MEDLINE | ID: mdl-16050966

RESUMO

OBJECTIVE: To determine the prevalence of caries, deft and DMFT indices (sum of decay, messing, and filling tooth in primary and permanent dentition), and the Significant Caries Index (SiC) in scholars from Leon, Nicaragua. PATIENTS AND METHOD: Dental data from a representative sample of 1,400 children were collected and analyzed in a cross-sectional study (year 2002). All subjects were clinically evaluated by one of two calibrated and standardized examiners. RESULTS: 28.6% children were caries free in both dentitions. Caries prevalence in primary teeth in 6-years-old children was 72.6% and 45.0% in permanent teeth in 12-years-old children. Mean deft and DMFT were 2.98 +/- 2.93 (n = 1,125) and 0.65 +/- 1.43 (n = 1,379), respectively. The SiC at 12 years of age was 4.12. Children with caries experience in primary teeth were more likely to have caries in permanent teeth (odds ratio = 2.48; 95% confidence interval, 1.66-3.79) than children without caries in primary teeth. CONCLUSION: Low caries prevalence and experience were observed in the permanent dentition, with a substantial proportion of filled teeth. Such favorable finding was not observed in the primary dentition. Levels of caries failed to meet the oral health goal of FDI/WHO for the year 2000 in 6-years-old. However, the levels found in 12-year-olds had already met the goal for 2000. The present findings confirmed prior reports that the caries experience in primary teeth is associated with the experience of caries in permanent teeth.


Assuntos
Cárie Dentária/epidemiologia , Fatores Etários , Criança , Intervalos de Confiança , Estudos Transversais , Índice CPO , Cárie Dentária/prevenção & controle , Dentição Permanente , Humanos , Nicarágua/epidemiologia , Razão de Chances , Dente Decíduo
16.
Gac. sanit. (Barc., Ed. impr.) ; 19(4): 302-306, jul. 2005. tab
Artigo em Es | IBECS | ID: ibc-040298

RESUMO

Objetivo: Determinar la prevalencia de caries dental, el índice de caries significativo (SiC) y los índices ceod y CPOD (suma de dientes cariados, perdidos/extraídos y obturados en la dentición temporal y permanente) en escolares de 6 a 12 años de edad de León, Nicaragua. Pacientes y método:Los datos dentales de una muestra representativa de 1.400 niños escolares fueron recogidos y analizados en un estudio transversal (año 2002). Todos los sujetos fueron examinados visual y clínicamente por uno de los 2 examinadores capacitados y estandarizados. Resultados: El 28,6% de los niños estaba libre de caries en ambas denticiones. La prevalencia de caries en la dentición temporal a los 6 años de edad fue del 72,6% y la de la dentición permanente a los 12 años fue del 45,0%. El SiC fue 4,12 en los niños de 12 años de edad. La media de los índices de caries (ceod y CPOD) para la muestra fue 2,98 ± 2,93 (n = 1.125) y 0,65 ± 1,43 (n = 1.379). Los niños con antecedentes de caries en la dentición temporal tuvieron mayor probabilidad de presentar caries en la dentición permanente (odds ratio = 2,48; intervalo de confianza del 95%, 1,66-3,79). Conclusión: Se observó una baja prevalencia de caries en la dentición permanente con un alto porcentaje de dientes obturados, a diferencia de lo observado en la dentición temporal. A unos años de las metas propuestas para el año 2000 (FDI/OMS), no se cumplieron los objetivos en los niños de 6 años de edad. Sin embargo, la meta para el año 2000 en niños de 12 años fue satisfactoria. Como en otros estudios, observamos que la experiencia de caries en la dentición temporal se encuentra asociada con la presencia de caries en la dentición permanente


Objective: To determine the prevalence of caries, deft and DMFT indices (sum of decay, messing, and filling tooth in primary and permanent dentition), and the Significant Caries Index (SiC) in scholars from Leon, Nicaragua. Patients and method: Dental data from a representative sample of 1,400 children were collected and analyzed in a cross-sectional study (year 2002). All subjects were clinically evaluated by one of two calibrated and standardized examiners. Results: 28.6% children were caries free in both dentitions. Caries prevalence in primary teeth in 6-years-old children was 72.6% and 45.0% in permanent teeth in 12-years-old children. Mean deft and DMFT were 2.98 ± 2.93 (n = 1,125) and 0.65 ± 1.43 (n = 1,379), respectively. The SiC at 12 years of age was 4.12. Children with caries experience in primary teeth were more likely to have caries in permanent teeth (odds ratio = 2.48; 95% confidence interval, 1.66-3.79) than children without caries in primary teeth. Conclusion: Low caries prevalence and experience were observed in the permanent dentition, with a substantial proportion of filled teeth. Such favorable finding was not observed in the primary dentition. Levels of caries failed to meet the oral health goal of FDI/WHO for the year 2000 in 6-years-old. However, the levels found in 12-year-olds had already met the goal for 2000. The present findings confirmed prior reports that the caries experience in primary teeth is associated with the experience of caries in permanent teethObjective: To determine the prevalence of caries, deft and DMFT indices (sum of decay, messing, and filling tooth in primary and permanent dentition), and the Significant Caries Index (SiC) in scholars from Leon, Nicaragua. Patients and method: Dental data from a representative sample of 1,400 children were collected and analyzed in a cross-sectional study (year 2002). All subjects were clinically evaluated by one of two calibrated and standardized examiners. Results: 28.6% children were caries free in both dentitions. Caries prevalence in primary teeth in 6-years-old children was 72.6% and 45.0% in permanent teeth in 12-years-old children. Mean deft and DMFT were 2.98 ± 2.93 (n = 1,125) and 0.65 ± 1.43 (n = 1,379), respectively. The SiC at 12 years of age was 4.12. Children with caries experience in primary teeth were more likely to have caries in permanent teeth (odds ratio = 2.48; 95% confidence interval, 1.66-3.79) than children without caries in primary teeth. Conclusion: Low caries prevalence and experience were observed in the permanent dentition, with a substantial proportion of filled teeth. Such favorable finding was not observed in the primary dentition. Levels of caries failed to meet the oral health goal of FDI/WHO for the year 2000 in 6-years-old. However, the levels found in 12-year-olds had already met the goal for 2000. The present findings confirmed prior reports that the caries experience in primary teeth is associated with the experience of caries in permanent teeth


Assuntos
Masculino , Feminino , Criança , Humanos , Cárie Dentária/epidemiologia , Restauração Dentária Permanente/estatística & dados numéricos , Índice CPO , Nicarágua/epidemiologia , Saúde Bucal/normas
17.
Gac. sanit. (Barc., Ed. impr.) ; 19(4): 302-306, jul. 2005. tab
Artigo em Es | IBECS | ID: ibc-041803

RESUMO

Objetivo: Determinar la prevalencia de caries dental, el índice de caries significativo (SiC) y los índices ceod y CPOD (suma de dientes cariados, perdidos/extraídos y obturados en la dentición temporal y permanente) en escolares de 6 a 12 años de edad de León, Nicaragua. Pacientes y método:Los datos dentales de una muestra representativa de 1.400 niños escolares fueron recogidos y analizados en un estudio transversal (año 2002). Todos los sujetos fueron examinados visual y clínicamente por uno de los 2 examinadores capacitados y estandarizados. Resultados: El 28,6% de los niños estaba libre de caries en ambas denticiones. La prevalencia de caries en la dentición temporal a los 6 años de edad fue del 72,6% y la de la dentición permanente a los 12 años fue del 45,0%. El SiC fue 4,12 en los niños de 12 años de edad. La media de los índices de caries (ceod y CPOD) para la muestra fue 2,98 ± 2,93 (n = 1.125) y 0,65 ± 1,43 (n = 1.379). Los niños con antecedentes de caries en la dentición temporal tuvieron mayor probabilidad de presentar caries en la dentición permanente (odds ratio = 2,48; intervalo de confianza del 95%, 1,66-3,79). Conclusión: Se observó una baja prevalencia de caries en la dentición permanente con un alto porcentaje de dientes obturados, a diferencia de lo observado en la dentición temporal. A unos años de las metas propuestas para el año 2000 (FDI/OMS), no se cumplieron los objetivos en los niños de 6 años de edad. Sin embargo, la meta para el año 2000 en niños de 12 años fue satisfactoria. Como en otros estudios, observamos que la experiencia de caries en la dentición temporal se encuentra asociada con la presencia de caries en la dentición permanente


Objective: To determine the prevalence of caries, deft and DMFT indices (sum of decay, messing, and filling tooth in primary and permanent dentition), and the Significant Caries Index (SiC) in scholars from Leon, Nicaragua. Patients and method: Dental data from a representative sample of 1,400 children were collected and analyzed in a cross-sectional study (year 2002). All subjects were clinically evaluated by one of two calibrated and standardized examiners. Results: 28.6% children were caries free in both dentitions. Caries prevalence in primary teeth in 6-years-old children was 72.6% and 45.0% in permanent teeth in 12-years-old children. Mean deft and DMFT were 2.98 ± 2.93 (n = 1,125) and 0.65 ± 1.43 (n = 1,379), respectively. The SiC at 12 years of age was 4.12. Children with caries experience in primary teeth were more likely to have caries in permanent teeth (odds ratio = 2.48; 95% confidence interval, 1.66-3.79) than children without caries in primary teeth. Conclusion: Low caries prevalence and experience were observed in the permanent dentition, with a substantial proportion of filled teeth. Such favorable finding was not observed in the primary dentition. Levels of caries failed to meet the oral health goal of FDI/WHO for the year 2000 in 6-years-old. However, the levels found in 12-year-olds had already met the goal for 2000. The present findings confirmed prior reports that the caries experience in primary teeth is associated with the experience of caries in permanent teeth


Assuntos
Criança , Humanos , Cárie Dentária/epidemiologia , Fatores Etários , Intervalos de Confiança , Estudos Transversais , Cárie Dentária/prevenção & controle , Dentição Permanente , Dente Decíduo , Nicarágua/epidemiologia , Razão de Chances , Apoio à Pesquisa como Assunto , Índice CPO
18.
Acta odontol. venez ; 42(3): 1-7, dic. 2004. tab, graf
Artigo em Espanhol | LILACS | ID: lil-400111

RESUMO

Objetivos: la caries dental es una enfermedad crónica, infecciosa, multifactorial y transmisible. Es muy prevalente y es la causa principal de pérdida dental durante la infancia. El objetivo del presente estudio fue determinar la prevalencia de pérdida de dientes y los patrones de caries en niños preescolares de una comunidad suburbana de Campeche, México. Material y métodos: se realizó un estudio transversal en 109 preescolares de 5-6 años de edad. Los criterios para diagnosticar caries dental fueron el índice ceod (OMS) y el "criterio de magnitud de la lesión cariosa" (CMLC). Se consideró como pérdida dental a la ausencia total del diente o al grado 4 del CMLC (pérdida mayor a 2/3 parte de la corona clínica). Los patrones de ataque de caries registrados fueron: 1) patrón anterior, 2) patrón posterior y 3) patrón anterior-posterior. Todos los sujetos fueron evaluados clínicamente por dos cirujanos dentistas capacitados y estandarizados (kappa <0.85). El análisis consistió en el cálculo de medidas de frecuencia, de tendencia central y de dispersión, según la escala de medición de las variables. El análisis bivariado se realizó con la prueba de chi2. Resultados: trece (11.9 por ciento) de los 109 sujetos tuvieron 34 (1.7 por ciento) de dientes perdidos de un total de 2041 piezas temporales examinadas. Los dientes perdidos con mayor frecuencia fueron los 2dos molares inferiores. De los sujetos con caries (n=82) 47.6 por ciento presentaron el patrón anterior-posterior, 46.3 por ciento tuvieron patrón posterior y 6.1 por ciento exhibieron patrón anterior. No existieron diferencias sustanciales en relación a la edad y sexo. Conclusiones: la pérdida dental en esta población fue alta. El patrón de mayor prevalencia fue el anterior-posterior


Assuntos
Humanos , Masculino , Pré-Escolar , Feminino , Criança , Distribuição por Idade , Estudos Transversais , Índice CPO , Incisivo , Dente Molar , Índice de Gravidade de Doença , Interpretação Estatística de Dados , Dente Decíduo , México
19.
Rev. obstet. ginecol. Venezuela ; 58(4): 217-229, dic. 1998. tab
Artigo em Espanhol | LILACS | ID: lil-301428

RESUMO

Indicar la importancia del asesoramiento genético para la prevención de los defectos del nacimiento y una reproducción sana, utilizando una población blanco altamente motivada, tal como la madre de alto riesgo para defectos del nacimiento. Selección de madres de alto riesgo en la consulta prenatal, la consulta de niños sanos, el servicio de ultrasonido y el registro de malformados. Hospital Chiquinquirá de Maracaibo y consultas públicas y privadas de la región. En once años, 576 pacientes, se atendieron en la consulta de genética. La ultrasonografía realizada por el genetista, demostró ser mas eficiente (38,23 por ciento) que la realizada en el servicio de ultrasonido (11,1 por ciento),(p>0,001; prueba de Z de una cola). La atención prenatal a la madre es incompleta sin el asesoramiento genético ya que a través del mismo, es posible la selección de un 10 por ciento a un 50 por ciento de embarazos de alto riesgo para defectos fetales cuya prevención de incidencia y recurrencia es posible, con beneficios económicos cuantificables para la nación


Assuntos
Humanos , Feminino , Gravidez , Perinatologia , Gravidez de Alto Risco , Diagnóstico Pré-Natal , Ginecologia , Obstetrícia , Venezuela
20.
Invest. clín ; 37(4): 271-8, dic. 1996.
Artigo em Espanhol | LILACS | ID: lil-199245

RESUMO

La incidencia de anencefalia en el Estado Zulia, y especialmente en la Costa Oriental del Lago de Maracaibo, zona de industrialización petrolera, se ha denunciado alta desde comienzos de los años 80, coincidiendo con la generalización del uso del ultrasonido diagnóstico en la evaluación fetal. Nosotros hemos analizado la incidencia de defectos del nacimiento a través del Programa Preventivo de Defectos del nacimiento, dentro del Hospital Chinquinquira de Maracaibo, basándose en cuatro estrategias mancomunadas: i) análisis de 32.331 ecogramas realizados entre 1993 y 1996, ii) registro de malformaciones congénitas durante el año de 1995, un estudio caso-control, iii) análisis de malformaciones motinatos remitidos al Servicio de Anatomia Patológia derivados de 4232 partos, y iv) registro de 638 madres con embarazo de alto riesgo fetal. Como población de referencia se utilizaron 345 historias del Servicio de Genética Médica y Diagnóstico Prenatal del Hospital Coromoto registradas a partir de 1981. Este enfoque nos ha permitido concluir que la incidencia de anencefalia en el Estado Zulia es de 0,75/1000, significativamente igual a la esperada en la mayoría de las poblaciones


Assuntos
Recém-Nascido , Humanos , Masculino , Feminino , Anencefalia/diagnóstico , Anencefalia/patologia , Anormalidades Congênitas/diagnóstico , Mortalidade Fetal , Incidência , Ultrassonografia
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