Influence of nano-structured alumina coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements

PURPOSE: The purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements. MATERIALS AND METHODS: A total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength (P<.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used. RESULTS: Groups treated with the nanostructured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating. CONCLUSION: Nano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.

Análisis de los factores ambientales y ocupacionales en la concentración de aerobacterias en unidades de cuidado intensivo del Hospital Universitario Fernando Troconis, 2009 Santa Marta- Colombia / Analysis of occupational and environmental factors in the concentration of aerobacters in intensive care units of the Fernando Troconis Universitary Hospital, 2009 Santa Marta-Colombia

Introducción: La evaluación de la calidad biológica del aire de ambientes hospitalarios resulta de especial interés debido a que los pacientes puedan servir como una fuente de bacterias patógenas para el personal del hospital, los visitantes y otros pacientes, siendo relevante en unidades de asistencia especializadas en atención de patologías crónicas como cáncer, SIDA y pacientes con trasplante de órganos o con complicaciones severas en su estado de salud, y que requieren una intervención masiva para su tratamiento en salas de cirugía y/o unidades de cuidado intensivo. Evaluar la influencia de factores ambientales y de ocupación de la unidad en la concentración de aerobacterias de unidades de cuidado intensivo del Hospital Universitario Fernando Troconis. Materiales y Métodos: Se colectaron muestras triplicadas con agar selectivo para Staphylococcus spp. y Pseudomonas spp., en dos estaciones de cada una de las tres UCI, mediante impactador de 2 etapas ubicado a altura de1.5m y caudal constante (28.3l/min) durante 5min, incubándolas a 37°C por 48h. Los factores ambientales se registraron con anemómetro Kestrel 4500 y ocupación de la unidad mediante registro manual del número de pacientes y personal asistencial de la unidad. Resultados: La máxima concentración fue 979.9±31.3UFC/m3 y el máximo promedio, 315.6±59.7UFC/m3. Staphylococcus spp. Superaron la concentración de Pseudomonas spp. La máxima ocupación fue en UCI Adulto, mayor temperatura en UCI Pediátrica y humedad más baja en UCI Adulto. Discusión y Conclusiones: La concentración de aerobacterias superó valores reportados por estudios aerobiológicos hospitalarios, y presenta relaciones leves con temperatura y escasa o nula con ocupación de la unidad.

Introduction: Assessing of biological quality of air in hospital environments is of particular interest because patients can be a source of pathogenic bacteria for hospital staff, visitors and other patients. It is relevant in specialized care of chronic diseases like cancer, AIDS and organ transplant patients or severe health complications, which require massive intervention for treatment in the operating room and/or intensive care units. To evaluate the influence of environmental factors and intensive care unit occupancy in the concentration of aerobacteria in intensive care units of Fernando Troconis Universitary Hospital. Materials and Methods: Triplicate samples were collected with selective agar for Staphylococcus spp. and Pseudomonas spp. using two-stage cascade impactor located 1.5 m high and constant flow (28.3l/min) for five minutes, locating two stations in each of the three ICU; the collected samples were incubated at 37°C for 48 hours. Environmental factors were recorded with anemometer Kestrel 4500 and occupancy of the unit by manually recording the number of patients and health care personnel of the unit. Results: Maximum concentration was 979.9±31.3CFU/m3 and maximum average 315.6±59.7CFU/m3. Staphylococcus spp. exceeded the concentration of Pseudomonas spp. Maximum intensive care unit occupancy was in adult ICU, higher temperature in pediatric ICU and lower humidity in adult ICU. Discussion and Conclusions: Aerobacteria concentration exceeded values reported by other aerobiological studies in hospital also has little relationship with temperature and little or no with intensive care unit occupancy.

Microbiological Identification and Distribution of Metal Components in Suspended Particulate Matter during Yellow Sand Phenomena at TaeAn Region in 2003 / 결핵및호흡기질환

BACKGROUND: Airborne particles during Yellow Sand phenomena are known to be associated with the respiratory disease. The purpose of this study was to evaluate the concentration and metal component properties of Yellow Sand particles and compare with airborne microbial concentration and species in non Yellow Sand and Yellow Sand phenomena. METHODS: Samplings were carried out in 2002 in Seosan, during non Yellow Sand and Yellow Sand phenomena. Samples were taken using the 8-stage Cascade impactor and metallic elements were analyzed by XRF. Those were culture on the media for bacterial and fungal culture and celline for virus. RESULTS: The concentration of total suspended particulate matter were respectively 80.2microgram/m3, 40.3microgram/m3 in non Yellow Sand and Yellow Sand phenomena. The concentration of metallic elements such as Ca, Fe, Cu and Zn in Yellow Sand phenomena were higher than its in non Yellow Sand. Two bacteria, Bacillus species and Staphylococcus were grown in two periods. In both periods, several fungal spores(Mucor species, Cladosporum, Alternaria, Aspergillus, Penicillium, and Alternaria species) were identified. The differences of bacteria and fungus species not observed in Yellow Sand and non Yellow Sand. Any viruses were not isolated in between both periods. CONCLUSIONS: The concentration of total suspended particulate matter and some metallic elements in Yellow Sand phenomena were higher than its in non Yellow Sand. The difference of bacteria and fungus species was not observed in non Yellow Sand and Yellow Sand phenomena.