Introduction: There is no reliable historical record of the evolution of the practice of dental laboratory workers in the Aburrá Valley. Therefore, the types of procedures, equipment, and materials that have been used since the beginning of this art or occupation, and how it has evolved to the present, are unknown. Objective: To characterize and learn about relevant aspects of the evolution of the practice of dental laboratory workers in the Aburrá Valley. Materials and methods: A quantitative, descriptive, cross-sectional investigation was carried out, 100 people who work in dental laboratories from family tradition to technicians and technologists graduated from different institutions of the city participated, who voluntarily decided to be part of the investigation, by signing an informed consent form. A survey was conducted to make a sociodemographic characterization and to know relevant aspects of the occupation. Sociodemographic variables, aspects relating to the practice as dental laboratory workers and its origin were taken into account. Results: A significant difference was found among the level of education and the pursuing of further study and areas of expertise. There is also a significant difference among age and level of education and age and the type of equipment in the laboratory, situations where the values ​​found have p <0.05. Conclusions: Most of the participants are empirical and technicians, and it is a concern that 94% of them do not know about the origin of the occupation in the Aburrá Valley, in addition, there are 28% who are not updated and prefer old techniques. However, the fact that most are updated and have analog and digital equipment stands out, which makes the market more and more competitive. In addition, relevant aspects were known about the evolution of the practice of dental laboratory workers in the Aburrá Valley.

Introduction: Cobalt – Chromium alloys have been used for the fabrication of cast frameworks which withstand the dental prostheses, failures that happen during the process of casting, polishing and finishing the framework generate surface quality defects which affect the mechanical properties of dentures. Objective: To characterize the surface quality defects in cast frameworks for Cobalt – Chrome dental prostheses by scanning electron microscopy (SEM). Materials and Methods: An experimental study was conducted, where 19 cast frameworks made out of Cobalt – Chrome alloy were conveniently selected. The following variables were taken into account during the casting process: presentation of the alloy, type of centrifugal casting, way of polishing, shining and sanding the framework. Results: The main characteristics observed, by scanning electron microscopy (SEM) analysis, in the cast frameworks for Cobalt – Chrome dental prostheses were: irregularities, superficial heterogeneity, presence of carbon and cracks. There was also found a statistically significant association between the presentation of the alloy and the polishing with shinning and without shinning, with a value of p (0,04). Conclusions: Characterization by scanning electron microscopy (SEM) allows us to detect surface quality defects which generate mechanical failures and damages within medium and long term use, affecting the quality of dental prostheses.

Objective: to describe surface and micro hardness defects in cobalt chromium structures for dental prostheses made using the CAD-CAM technique. Method: Type of descriptive study. Population and sample: 10 cobalt-chromium alloy frameworks for 3-piece bar-type dental prostheses, dimensions 10 cm x 1.5 cm. The plaster model was obtained from a conventio-nal impression, the model was prepared for scanning and the design of the structure, then the structure was ordered to be milled under the supervision of the project researchers. Subsequently, they were analyzed in the scanning electron microscope and in the Shimadzu Micro Vickers Hardness Tester HMV-G 21 equipment. Results: through the scanning electron microscopy, images with magnifications of various sizes were obtained where different defects of surface such as surface irregularities, dirt and foreign bodies. The samples milled with three axes are found to have a hardness of 294.6 ± 21 HK0.1 and an elastic modulus of 239 ± 22.3 GPa, while the samples milled with five axes have a hardness of 336.2 ± 20.9 HK0.1 and an elastic modulus of 237.7 ± 18.3 GPa. Conclusions: through scanning electron microscopy, surface defects were observed that are not visible to the naked eye, such as surface irregularities, unevenness and mainly fatty dirt due to the high carbon content. However, cracks and porosities are not observed. Milling has a slight influence on the hardness, but not on the elastic modulus of the alloy.

Introducción: El yeso utilizado en la elaboración de prótesis dentales es el sulfato de calcio di hidratado CaSO4 (2H2O) casi puro, debido a que es indispensable para la obtención de modelos de estudio y laboratorio, además, representa un 55% de los residuos generados en los laboratorios dentales, es desechado sin identificar y clasificar; a la fecha, no hay protocolos para su disposición final que permitan su aprovechamiento y potencialidad del material reciclado. Objetivo: Realizar un protocolo para el reciclaje los residuos de yeso generados en los procesos de elaboración de prótesis dentales. Metodología: Se realizó una investigación experimental de enfoque cuantitativo. Las etapas del proceso de reciclaje fueron: recolección, cuantificación de los residuos de yesos tipo II, III, IV, limpieza, trituración, pre secado, tamizado, pesaje, empacado y rotulación del material reciclado. Además, se elaboraron probetas cilíndricas de 20 mm de diámetro con 40 mm de altura que sirvieron para someter el material a pruebas mecánicas. Resultados: luego de establecer un protocolo de adecuación de los residuos de yeso, el material se sometió a ensayos mecánicos y de acuerdo a las pruebas mecánicas de la Norma Técnico Colombiana NTC 562 de materiales dentales - yeso dental, el material reciclado tiene buenas propiedades mecánicas. Conclusiones: Se estableció un protocolo de adecuación del yeso reciclado y un protocolo para procedimientos de laboratorio en los cuales se puede utilizar el material reciclado, contribuyendo de esta forma al desarrollo sostenible y calidad ambiental en los procesos de elaboración de prótesis dentales.