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Abstract Introduction: Dentists are a population at high risk of hearing loss due to their constant exposure to instruments that can generate noise of up to 100 dB during their practice. Objective: To determine the level of knowledge of dentists working in Chile regarding hearing loss caused by exposure to noise generated by dental instruments. Materials and methods: A cross-sectional study was conducted in 114 dentists, who completed a virtual survey of 22 questions regarding the perception and level of knowledge about hearing loss due to exposure to loud noises and about national regulations on occupational noise exposure. Differences between perception and knowledge levels were evaluated taking into account the years of professional practice and the average weekly workload in dental treatment rooms. Descriptive and inferential statistics (Chi-squared test) were used for data analysis. Results: Most participants were Chilean (99.1%); 58.8% were women, and 72.8% had less than 10 years of professional experience. In addition, 97.4% were unaware of national regulations on occupational noise exposure and 50% of the sample reported having experienced hearing loss; of these, 57.9% (n = 32) associated it with their practice. Conclusions: A very low percentage of participants knew that there are regulations regarding occupational noise exposure. For this reason, it is important that, both during their training and their professional practice, dentists in Chile have greater access to information about these regulations and hearing protection measures.
Resumen Introducción. Los odontólogos son una población con un alto riesgo de desarrollar pérdida auditiva debido a la constante exposición a instrumentales que deben usar en su práctica profesional y que pueden generar ruidos de hasta 100 dB. Objetivo. Determinar el nivel de conocimiento de odontólogos laboralmente activos en Chile respecto a la pérdida auditiva causada por la exposición al ruido generado por maquinarias dentales. Materiales y métodos. Estudio transversal realizado en 114 odontólogos, quienes diligenciaron una encuesta virtual de 22 preguntas relativas a la percepción y el nivel de conocimiento sobre pérdida auditiva por exposición a ruidos fuertes y sobre la normativa nacional respecto a exposición ocupacional al ruido. Se evaluaron las diferencias entre percepción y niveles de conocimiento según los años de ejercicio profesional y la carga promedio de trabajo semanal en boxes de atención. Para el análisis de los datos se utilizó estadística descriptiva e inferencial (prueba de chi-cuadrado). Resultados. La mayoría de participantes eran chilenos (99.1%); el 58.8% fueron mujeres, y el 72.8% tenía menos de 10 años de ejercicio profesional. Además, el 97.4% desconocía las regulaciones nacionales sobre exposición ocupacional al ruido y el 50% reportó haber experimentado pérdida auditiva; de estos, 57.9% (n=32) lo asoció a su profesión. Conclusiones. Un muy bajo porcentaje de los participantes sabe que hay disposiciones sobre exposición ocupacional al ruido, por lo que es importante que, tanto en su formación, como durante su ejercicio profesional, los odontólogos en Chile tengan un mayor acceso a información relativa a estas normativas y a medidas ocupacionales de protección auditiva.
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OBJECTIVE: To evaluate influences of vitrification and warming of metaphase II (MII) mouse oocytes on survival, spindle dynamics, spindle morphology, and chromatin alignment on metaphase plates. DESIGN: Experimental animal study. SETTING: University animal laboratory. ANIMAL(S): Eight-week-old B6D2F1 mice. INTERVENTION(S): Denuded MII oocytes were used fresh (control), exposed to vitrification/warming solutions (Sol Expos), or vitrified and warmed (Vitr). MAIN OUTCOME MEASURE(S): Oocyte recovery and survival after warming and the influence of solution exposure and cryopreservation on spindle dynamics and chromatin alignment. RESULT(S): Cryopreservation of two or 10 oocytes per straw resulted in recovery (100% +/- 0% and 95% +/- 4%, respectively; mean +/- SE) and survival (95% +/- 2% and 98% +/- 2%, respectively). Immediately after warming (Vitr), significantly fewer oocytes assessed with immunocytochemistry contained spindles, compared with control and Sol Expos. When oocytes were placed into a 37 degrees C environment for 2 hours after exposure or warming, the ability to recognize spindles by immunocytochemistry was not significantly different between groups. Using live-cell time-lapse imaging with LC-Polscope, similar time-dependent spindle formation dynamics were observed. At 2 hours after collection or treatment, spindle morphology and length were not significantly different between the groups, nor was the incidence of aberrant alignment of chromatin on metaphase plates. CONCLUSION(S): Immediately after warming of vitrified MII oocytes, beta-tubulin is depolymerized and chromatin remains condensed on the metaphase plate. Within a 2-hour period, beta-tubulin repolymerizes, forming morphologically normal metaphase spindles with properly aligned chromatin.