1,082 research outputs found

    Bone implant sockets made using three different procedures: a stability study in dogs

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    Objective: This study compared the effects of three different methods of preparing bone implant sockets (drilling, osteotomes, and piezoelectric device) on osseointegration using resonance frequency analysis (RFA). Study Design: An experimental prospective study was designed. Material and methods: Ten adult beagle dogs were studied. After 5 weeks, 23 out of 28 initially placed implants in the iliac crest were evaluated, comparing these three different procedures of bone implant socket. Student's ttest (paired, two-tailed) was used to reveal differences among the three groups at each time point (SPSS 16.0, IL, USA). Results: After a 5-week healing period, the implants placed in sockets that were made using an osteotome or piezoelectric device were slightly more stable than those made by drilling. Reduced mechanical and heat injury to the bone is beneficial for maintaining and improving stability during the critical early healing period. Conclusion: Using RFA, there was evidence of a slight increase in implant stability in the iliac crest after 5 weeks of healing when the implant socket was made using a piezoelectric device or expansion procedure as compare with the drilling method

    Oral cancer, HPV infection and evidence of sexual transmission

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    The incidence of oropharyngeal cancer and oral cancer is growing worldwide, both in young non-smokers and in young non-drinkers (smoking and drinking are considered the main risk factors). Epidemiologic studies suggest a strong association between the infection by human papillomavirus (HPV), especially types 16 and 18 (high oncological risk) which have already demonstrated their etiological role in anal tumours as well as in cervix cancer. There is clear epidemiologic evidence that both types of tumours relate to changes in sexual behaviour and that both are linked to sexual transmission of HPV. The number of oral and oropharyngeal cancer cases is rising nowadays, especially among young individuals with no typical toxic habits, such as tobacco and/or alcohol. In this review we set out to update the aspects related to the onset of oral cancer, its relationship with HPV infection and whether this association may be due to the sexual transmission of the virus

    “Sexismo y homofobia en estudiantes de 4to y 5to de secundaria de una institución educativa pública del distrito de Los Olivos, 2018”

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    Esta investigación tiene como finalidad, conocer la relación entre el sexismo y la homofobia en estudiantes de 4to y 5to de secundaria de una institución educativa pública del distrito de Los Olivos, 2018. Se desarrolló este trabajo desde el enfoque cuantitativo con alcance descriptivo y, bajo las pautas del diseño no experimental de corte transversal. Se recoge información en base a una muestra constituida por 511 estudiantes de nivel secundaria, cuyas edades fluctuaban entre los 14 y 17 años, los instrumentos empleados fueron la escala de sexismo en adolescentes de Recio, Cuadrado y Ramos en 2007 y la escala de homofobia moderna de Sheela Raja. Los resultados indican que existe una correlación directa y significativa en las variables de sexismo y homofobia (Rho = ,103*) y (sig = ,020), donde se muestra que a mayor actitud sexista, menor será la actitud homofóbica

    Estudio de la anquilosis dental en una población infantil

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    Dentoalveolar ankylosis is a process defined as the fusión of the tooth’s root to the surrounding alveolar bone, due to a root resorption and a new bone formation throught substitution. The purpose of this study was to analyze the prevalence of dental ankylosis in a sample of 402 children between 6 and 9 years. We found a prevalence of 4,97%, more frequently in boys and with the highest rate of incidence ocurring in the group of 8 years. These results are similar to the findings other authors have found through the years.La anquilosis dentoalveolar se define como el proceso por el cual se produce la unión de la raíz de un diente al hueso alveolar circundante, debido a una reabsorción radicular y una formación de hueso por sustitución. El propósito de este estudio fue analizar la prevalencia de anquilosis en un grupo de pacientes infantiles con una muestra de 402 niños de entre 6 y 9 años. Se encontró una prevalencia del 4,97%, siendo más frecuente en niños y con el pico de incidencia en los 8 años de edad. Estos resultados se asemejan a los hallazgos de otros autores a lo largo de los años

    A front-fixing method for American option pricing on zero-coupon bond under the Hull and White model

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    ABSTRACT: A new efficient numerical method is proposed for valuation of American option on zero-coupon bond using Hull and White model. By applying the front-fixing transformation suggested by Holmes and Yang, the original free boundary problem is transformed into a new fixed boundary partial differential equation (PDE) problem, where the optimal stopping boundary is one of the unknowns of the problem. The numerical finite difference scheme for the transformed problem is constructed. Stability and convergence rate is studied empirically. Numerical simulation of the computation of both the option price and the optimal stopping boundary are illustrated with examples and the comparison with the Hull and White tree method.This work has been partially supported by the Ministerio de Ciencia, Innovación y Universidades, Spanish grant MTM2017-89664-P

    Evaluación de 80 implantes, sometidos a carga inmediata en desdentados inferiores tras un seguimiento de dos años

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    Objetivo: Analizar el comportamiento tanto clínico como radiológico de ochentas implantes con una nueva superficie tratada mediante una disolución de ácido sulfúrico y fluorhídrico con posterior tratamiento térmico, que han sido sometidos a carga inmediata en pacientes rehabilitados con sobredentaduras inferiores. Diseño del artículo: Estudio observacional, prospectivo en 20 pacientes rehabilitados con sobredentaduras inferiores, soportadas sobre cuatro implantes de 13 milímetros de longitud. Todos los pacientes fueron planificados e incluídos tras el consentimiento, anamnesis, exploración clínica y estudio radiográfico y mediante montaje clínico previo de la prótesis inferior. Resultados: Durante los dos años de seguimiento, se ha obervado que el acúmulo de placa y cálculo no ha sido importante, oscilando los índices (Silness y Löe) entre 0 y 1. El sondaje periodontal, ha sido favorable no encontrando pacientes que superasen 2 milímetros. Los controles radiográficos mostraron a lo largo del seguimiento ausencia de fracaso implantológico. Las pérdidas óseas cervicales, durante el primer año, no existieron en un alto porcentaje (65%), mientras que en un 10% se produjo la reabsorción de la mitad cervical y en el 35% restante sobre las ¾ partes cervicales. El comportamiento durante el segundo año fue compatible a los patrones estándares, observándose pérdidas que oscilaron entre 0,5 y 1,5 milímetros. Conclusiones: La rehabilitación mediante sobredentaduras inferiores, debiera contemplarse como una indicación prioritaria, planteándose la sustitución de los tratamientos implantológicos con períodos de reposo convencionales y/o precoces.Aim: An analysis is made of the clinical and radiological behavior of 80 implants with a new surface subjected to etching with a sulfuric and hydrofluoric acid solution followed by thermal treatment, and subjected to immediate loading in patients with lower overdentures. Study design: A prospective observational study was made of 20 patients with lower overdentures supported by four implants measuring 13 mm in length. All patients were included after the obtainment of informed consent, anamnesis, clinical examination and radiological study, with prior clinical elaboration of the lower dentures. Results: Over two years of follow-up, no important plaque or tartar accumulation was observed (with Silness and Löe indexes of 0-1). Periodontal probing proved favorable, with no pocket depths of over 2 mm in any case. The radiological controls showed no implant failures during follow-up. No cervical bone loss was recorded in the first year in a large proportion of cases (65%), while reabsorption of the cervical half was observed in 10%, and of three-quarters of the cervical portion in the remaining 35%. Performance in the second year was compatible with the standard references ' with losses of between 0.5-1.5 mm. Conclusions: Rehabilitation with lower overdentures should be regarded as a priority indication, and implantological treatment substitution by conventional and/or early resting periods should be considered

    Role of the dental surgeon in the early detection of adults with underlying HIV infection / AIDS

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    A review is made of the late diagnosis of human immunodeficiency virus (HIV) infection, a subject of growing interest in public health. It has been estimated that in Europe 30% of all HIV-infected people are unaware of their seropositive condition, and this in turn is associated with a poorer long-term disease prognosis and an increased risk of transmission to other individuals. The role of the dental surgeon in this context could be of great importance, since there are many oral lesions that can suggest the existence of underlying infection. The study also addresses the controversial subject of rapid HIV testing, and whether these tests should be performed on a routine basis in the dental clinic, or whether it is preferable to refer the patient to a specialized center

    Biomimetic Citrate-Coated Luminescent Apatite Nanoplatforms for Diclofenac Delivery in Inflammatory Environments

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    This research was funded by Spanish Agencia Estatal de Investigacion (AEI) of the Ministerio de Ciencia e Innovacion (MCI) and co-funded with FEDER, UE, Project No. PGC2018-102047-B-I00 (MCIU/AEI/FEDER, UE). M.P. acknowledges the Progetto di Ricerca Fondi di Ateneo per la Ricerca-FAR 2018 "Development of innovative biological materials for the functional regeneration of cardiac tissue models".Luminescent nanoparticles are innovative tools for medicine, allowing the imaging of cells and tissues, and, at the same time, carrying and releasing different types of molecules. We explored and compared the loading/release ability of diclofenac (COX-2 antagonist), in both undoped- and luminescent Terbium(3+) (Tb3+)-doped citrate-coated carbonated apatite nanoparticles at different temperatures (25, 37, 40 degrees C) and pHs (7.4, 5.2). The cytocompatibility was evaluated on two osteosarcoma cell lines and primary human osteoblasts. Biological effects of diclofenac-loaded-nanoparticles were monitored in an in vitro osteoblast's cytokine-induced inflammation model by evaluating COX-2 mRNA expression and production of PGE(2). Adsorption isotherms fitted the multilayer Langmuir-Freundlich model. The maximum adsorbed amounts at 37 degrees C were higher than at 25 degrees C, and particularly when using the Tb3+ -doped particles. Diclofenac-release efficiencies were higher at pH 5.2, a condition simulating a local inflammation. The luminescence properties of diclofenac-loaded Tb3+ -doped particles were affected by pH, being the relative luminescence intensity higher at pH 5.2 and the luminescence lifetime higher at pH 7.4, but not influenced either by the temperature or by the diclofenac-loaded amount. Both undoped and Tb3+-doped nanoparticles were cytocompatible. In addition, diclofenac release increased COX-2 mRNA expression and decreased PGE(2) production in an in vitro inflammation model. These findings evidence the potential of these nanoparticles for osteo-localized delivery of anti-inflammatory drugs and the possibility to localize the inflammation, characterized by a decrease in pH, by changes in luminescence.Spanish Agencia Estatal de Investigacion (AEI) of the Ministerio de Ciencia e Innovacion (MCI)European Commission PGC2018-102047-B-I0

    Surgical ciliated cyst of the maxilla. Clinical case

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    Surgical ciliated cyst is uncommon in Western countries but frequently reported in Asian populations as a delayed complication of surgery, with inclusion in the bone of nasal or sinus mucosa. Isolated cases have also been reported in the mandible after orthognathic surgery. We report a case in the maxillary region three years after radical sinus surgery for chronic sinusitis. Intraoral examination revealed a small painless tumefaction with no color change in the surrounding tissues. Computed tomography demonstrated a well-defined intraosseous lesion lateral to the maxillary sinus. The lesion was completely excised, when histology demonstrated a pseudostratified ciliated epithelial lining. Differential diagnosis from other lesions such as an odontogenic keratocyst or inflammatory cyst were also made. This case report,uncommon in Western countries, of a surgical ciliated cyst illustrates the need for a meticulous surgical technique, proper management of complications, and routine, long-term follow-up of patients undergoing any type of sinus surgery

    Retrospective study of 149 cases of salivary gland carcinoma in a Spanish hospital population

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    The clinical and histological characteristics of salivary gland tumors vary widely, complicating their diagnosis and management, and major differences have been recorded in the distribution of histopathological diagnoses among different countries. This retrospective study reviewed the demographic (age, sex) and clinicopathological (pathology diagnosis and localization) characteristics of cases diagnosed with primary SGC between June 1992 and May 2014 in the Pathology Department of the 12 de Octubre Hospital of Madrid. Diagnoses were recorded according to the 2005 WHO classification. The study included 149 SCG patients, aged between 11 and 94 yrs, with mean age at onset of 55.56 yrs and peak incidence in the eighth decade of life. The male:female ratio was 1.01. The parotid gland was the most frequently involved (75.2%). The most frequent carcinoma was mucoepidermoid carcinoma (24.2%), followed by acinic cell carcinoma (15.4%). The demographic and histopathological characteristics of patients with salivary gland carcinomas in Spain, reported here for the first time, are broadly similar to those found in other countries
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