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INTRODUCTION: Three-dimensional (3D)-printing technology can provide customizable simulations, but its effects on patient care quality have not been well studied. This study aimed to assess the impact of practicing with patient-specific 3D-printed teeth models on the quality of patients' dental preparations performed by students transitioning to clinical training. Accordingly, the quality of posterior crown preparations was evaluated by objectively analyzing digital scans and grades in two groups: the study group, which practiced beforehand with patient-specific 3D-printed teeth models, and the control group, which did not practice with these models. METHODS: All 78 fourth-year dental students who had just finished their fixed prosthodontics course at the simulation laboratory with training on phantom heads and without previous clinical experience in crown preparations were invited to participate in the study. Sixty-eight agreed to take part and were randomly divided into a study group that practiced crown preparations on 3D-printed models of their own patient's teeth and a control group that did not practice with 3D-printed models and started their clinical work straightforwardly after simulation training. Students completed validated perception questionnaires on self-confidence and clinical skills before and after the protocol, which were compared using a chi-squared test. Crown preparations performed on 3D-printed models and then on patients were digitally scanned and objectively graded by prepCheck software for critical parameters, such as undercuts, taper, and occlusion reduction. Non-parametric tests were used to compare preparations on 3D-printed models and on patients performed by the study group and those on patients made by the control group. RESULTS: Initially, both groups reported similar perceptions of self-confidence and clinical skills levels. The study group significantly improved both aspects after the protocol. Analysis of the scanned preparations demonstrated that the study group removed less tooth structure from actual patients than from the initial 3D-printed models. In contrast, the control group showed excess occlusal clearance in their patients compared to the study group. CONCLUSIONS: Practicing patient-specific 3D-printed teeth before performing procedures clinically appears to enhance preparation quality and minimize unnecessary tooth reduction in early clinical experiences.
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Arsenic (As), a semimetal toxic for humans, is commonly associated with serious health problems. The most common form of massive and chronic exposure to As is through consumption of contaminated drinking water. This study aimed to isolate an As resistant bacterial strain to characterize its ability to oxidize As (III) when immobilized in an activated carbon batch bioreactor and to evaluate its potential to be used in biological treatments to remediate As contaminated waters. The diversity of bacterial communities from sediments of the As-rich Camarones River, Atacama Desert, Chile, was evaluated by Illumina sequencing. Dominant taxonomic groups (>1%) isolated were affiliated with Proteobacteria and Firmicutes. A high As-resistant bacterium was selected (Pseudomonas migulae VC-19 strain) and the presence of aio gene in it was investigated. Arsenite detoxification activity by this bacterial strain was determined by HPLC/HG/AAS. Particularly when immobilized on activated carbon, P. migulae VC-19 showed high rates of As(III) conversion (100% oxidized after 36 h of incubation). To the best of our knowledge, this is the first report of a P. migulae arsenite oxidizing strain that is promising for biotechnological application in the treatment of arsenic contaminated waters.
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Resumen La participación es un derecho humano que debe ser garantizado. No obstante, variadas restricciones físicas y sociales dificultan el involucramiento de las personas con condiciones neurológicas en su comunidad. Muchos países de Latinoamérica no cuentan con instrumentos validados que permitan analizar la participación de estos grupos. Por esta razón, a través de un diseño instrumental esta investigación evalúa las propiedades psicométricas del cuestionario de hábitos de vida (LIFE-H) en una muestra de 123 personas con parálisis cerebral entre 9 y 21 años (M = 14.14; DE=2.89). Se detectaron adecuados índices de consistencia interna. No se replicó la estructura de dos dimensiones mediante análisis factorial confirmatorio. Sin embargo, el análisis factorial exploratorio de los datos evidenció un factor general que explicó el 69.55 % de la varianza. Se concluye que el LIFE-H es un instrumento idóneo para el estudio de la participación como un constructo global en esta población.
Abstract Participation is a human right that must be guaranteed. However, various physical and social restrictions make it difficult for people with neurological conditions to participate in their community. Many Latin American countries do not have validated instruments to analyze the participation of these groups. The present investigation used an instrumental design to evaluate the psychometric properties of the Life Habits Assessment Questionnaire (LIFE-H) in a sample of 123 people with cerebral palsy between 9 and 21 years old (M = 14.14; DE=2.89). Adequate internal consistency indices were detected. The two-dimensional structure proposed by the authors was not replicated through confirmatory factor analysis. However, the exploratory factor analysis of the data evidenced a general factor that explained 69.55 % of the variance. It is concluded that LIFE-H is an ideal instrument for the study of participation as a global construct in this population.
