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Objective The aim of this study was to test the plausibility of using the ΦX174 bacteriophage as a tracer of viral aerosols spreading in a dental aerosol-generating procedure (AGP) model. Methods ΦX174 bacteriophage (~ 108 plaque-forming units (PFU)/mL) was added into instrument irrigation reservoirs and aerosolized during class-IV cavity preparations followed by composite fillings on natural upper-anterior teeth (n = 3) in a phantom head. Droplets/aerosols were sampled through a passive approach that consisted of Escherichia coli strain C600 cultures immersed in a LB top agar layer in Petri dishes (PDs) in a double-layer technique. In addition, an active approach consisted of E coli C600 on PDs sets mounted in a six-stage cascade Andersen impactor (AI) (simulating human inhalation). The AI was located at 30 cm from the mannequin during AGP and afterwards at 1.5 m. After collection PDs were incubated overnight (18 h at 37 °C) and bacterial lysis was quantified. Results The passive approach disclosed PFUs mainly concentrated over the dental practitioner, on the mannequin’s chest and shoulder and up to 90 cm apart, facing the opposite side of the AGP’s source (around the spittoon). The maximum aerosol spreading distance was 1.5 m in front of the mannequin’s mouth. The active approach disclosed collection of PFUs corresponding to stages (and aerodynamic diameters) 5 (1.1–2.1 µm) and 6 (0.65–1.1 µm), mimicking access to the lower respiratory airways. Conclusion The ΦX174 bacteriophage can be used as a traceable viral surrogate in simulated studies contributing to understand dental bioaerosol’s behavior, its spreading, and its potential threat for upper and lower respiratory tract. Clinical relevance The probability to find infectious virus during AGPs is high. This suggests the need to continue characterizing the spreading viral agents in different clinical settings through combination of passive and active approaches. In addition, subsequent identification and implementation of virus-related mitigation strategies is relevant to avoid occupational virus infections.

Objetivo: Validar un cuestionario para la identificación de factores asociados al desgaste dental erosivo (ETW) en adolescentes. Materiales y métodos: Con base en cuestionarios previos, se diseñó un instrumento de 73 preguntas (cuatro dominios: sociodemográficos, historia de salud general/bucal, dieta y hábitos de cuidado bucal). La validez de contenido fue evaluada por cinco expertos externos y la comprensibilidad de las preguntas fue evaluada en un estudio piloto (10 adolescentes). Tres expertos internos acordaron modificaciones. La validez de constructo se evaluó luego de aplicar el cuestionario resultante a 454 jóvenes de 12 a 15 años de Bogotá (Colombia). Los análisis estadísticos incluyeron análisis factorial exploratorio (AFE), consistencia interna y análisis factorial confirmatorio (CFA). Resultados: Después de la validación de contenido, el 52% de las preguntas fueron excluidas y las 38 preguntas restantes fueron ajustadas. Validación de constructo: El EFA resultó en la reagrupación de preguntas en los tres dominios restantes (KMO = 0,68; prueba de Bartlett: p < 0,001). La consistencia interna fue buena (cuestionario general α de Cronbach = 0,67; α de Cronbach de los factores individuales = 0,30-0,69; ICC = 0,39-0,62; p < 0,001), y el modelo mostró un ajuste satisfactorio. CFA mostró una buena validez convergente y discriminatoria sugiriendo la eliminación de 14 preguntas adicionales (χ2 = 238.518; p > 0.086; CFI = 0.96; TLI = 0.95; RMSEA = 0.017; PRATIO = 0.76). El cuestionario final validado constaba de 24 preguntas (antecedentes de salud general/oral: n = 5; hábitos dietéticos: n = 15; hábitos de cuidado bucal: n = 4). Conclusión: La validación del cuestionario ETW para adolescentes fue satisfactoria y resultó en una versión breve del cuestionario aplicable. Relevancia clínica: Este estudio logró un cuestionario satisfactoriamente validado, breve y aplicable para evaluar los factores de riesgo de desgaste dental erosivo en adolescentes, recomendado para la práctica clínica, la investigación y la epidemiología. Objective: To validate a questionnaire for the identification of factors associated with erosive tooth wear (ETW) in adolescents. Materials and methods: Based on previous questionnaires, a 73-question instrument was designed (four domains: socio-demographics, general/oral health history, diet and oral care habits). Content validity was assessed by five external experts, and the questions’ understandability was evaluated in a pilot study (10 adolescents). Three internal experts agreed on modifications. Construct validity was assessed after the resulting questionnaire was applied to 454 12- to 15-year olds from Bogotá (Colombia). Statistical analyses included exploratory factor analysis (EFA), internal consistency, and confirmatory factor analysis (CFA). Results: After the content validation, 52% of the questions were excluded and remaining 38 questions were adjusted. Construct validation: The EFA resulted in the regrouping of questions into the three remaining domains (KMO = 0.68; Bartlett’s test: p < 0.001). Internal consistency was good (general questionnaire Cronbach’s α = 0.67; individual factors’ Cronbach’s α = 0.30–0.69; ICC = 0.39–0.62; p < 0.001), and the model showed satisfactory fit. CFA showed good convergent and discriminatory validity suggesting the elimination of 14 additional questions (χ2 = 238.518; p > 0.086; CFI = 0.96; TLI = 0.95; RMSEA = 0.017; PRATIO = 0.76). The final validated questionnaire comprised 24 questions (general/oral health history: n = 5; dietary habits: n = 15; oral care habits: n = 4). Conclusion: The validation of the ETW questionnaire for adolescents was satisfactory and resulted in a short applicable questionnaire version. Clinical relevance: This study achieved a satisfactorily validated, short, and applicable questionnaire for assessing erosive tooth wear risk factors in adolescents, recommended for the clinical practice, research, and epidemiology.

Introduction and objective: dental fluorosis severity reflects fluoride exposure during dental enamel development. Recently, prenatal and postnatal exposure to fluoride has been associated with negative neurodevelopmental outcomes. The aim of this study was to describe and compare the severity and distribution pattern of dental fluorosis in the primary and permanent dentition, as a basis to discuss the timing and extent of fluoride exposure of children living in endemic areas of fluorosis in the department of Huila. Materials and methods: 840 children (preschoolers and schoolchildren) from four municipalities of the Huila Department were examined by trained dentists for dental fluorosis using the Thylstrup & Fejerskov Index. To estimate the prevalence of severities of fluorosis, each child was classified according to the most severe score. The distribution of the prevalence of enamel fluorosis severity by age-group and type of dentition were reported as prevalence rates (%). Results: Prevalence of dental fluorosis in preschoolers was of 97.2% and in schoolers of 99.9%. For both preschoolers and schoolers moderate fluorosis was the most prevalent (75.6% and 63.5%, respectively). For both primary and permanent teeth, mild fluorosis was more prevalent in anterior teeth than in posterior teeth. Moderate and severe fluorosis were more prevalent in posterior teeth than in anterior teeth. Conclusions: the distribution pattern of the severity of dental fluorosis suggests both prenatal and postnatal exposure to fluoride above recommended levels. This study raises the importance of the validation of dental fluorosis as a potential historical biomarker of fluoride exposure at moments that are critical for neurodevelopment.

A three-phase system consisting of alumina (Al2O3), magnesia (MgO) and 8 mol% yttria‐stabilized zirconia (8YSZ) was reactive flash sintered to produce MgAl2O4-8YSZ composites. We show that a critical volume fraction of the ionic conductor 8YSZ is required to promote the flash phenomenon, indicating a typical percolation behavior. The easy path for conduction could be reached with a smaller critical volume fraction when using agglomerated powders for producing the green bodies. Furthermore, microstructure and X-ray diffraction analyses demonstrate that both sintering and phase transformation largely depend on the mixing level of the precursors. Although the presence of agglomerates resulted in a decrease of the flash onset temperature, poor sintering and incomplete phase transformation were verified. This behavior is attributed to inhomogeneous heat distribution within those samples during the flash state, which could be explained by the electrical current percolation.

We investigate the reactive flash sintering of Mg0.2Ni0.2Co0.2Cu0.2Zn0.2O precursor powders prepared by a polymeric synthesis route. The flash experiments were performed at a constant heating rate of 10 °C min−1 with electric fields from 15 to 60 V cm−1. The single-phase rock-salt structure was obtained in just a few seconds at furnace temperatures as low as 500 °C, under an electric field of 60 V cm−1 and a current density of 150 mA mm−2. Success at processing an entropy-driven phase in a remarkably short time and low furnace temperature demonstrates the potential of reactive flash sintering for producing entropy-stabilized materials.

Roughness-tactile perception is part of activity assessment in initial-caries-lesions. Hypothesizing that a probe’s design influences this examiner’s assessment, four probes were designed. The aims of this study were to select the probe with highest inter-/intra-examiners’ roughness-assessment agreement and to determine its diagnostic accuracy on artificial initial-caries lesions. A pilot study was conducted with trained dentists to select one controlled-pressure probe design (n = 4) by assessing roughness on known-roughness metal plaques with 5-point Likert scale. Diagnostic accuracy of roughness assessment was conducted with the selected controlled-pressure probe and the WHO-probe on sound and artificial initial-caries-lesion (n = 20) human enamel blocks. Intra-class correlation coefficients (ICCs) and quadratic weighted-Kappa scores were used to assess examiners’ reproducibility and Multilevel Poisson models to determine diagnostic accuracy between both probes controlling for confounding variables. The probe design with the highest inter/intra-examiner’s agreement (ICC = 0.96) was selected for subsequent analyses. Unadjusted sensitivity, specificity and accuracy values were for the controlled-pressure and the WHO probes: 71.1%,90.6%,81.2%, and 67.4%,84.6%,75.8%, respectively (p > 0.05). Examiner remained the most important factor influencing diagnostic accuracy. While this study did not show significantly higher diagnostic accuracy of the designed controlled-pressure vs. the WHO-probe when used by trained dentists, all over roughness-assessment accuracy and reproducibility were high.

We report the transformation of an amorphous mixture of Li0.5La0.5TiO3 (LLTO) directly into a single phase dense polycrystal, all within a few seconds at about 800 °C by the flash method. The starting material is a chemically-prepared precursor powder that experiences concurrent crystallization and densification to cubic LLTO during the flash event, as shown by in-situ X-ray measurements. The experiments were conducted at a constant heating rate with fields from 80 to 120 V cm−1 and a current limit of 60 mA mm–2. The resulting polycrystal yielded a bulk conductivity of 0.5 mS cm–1.

Short sintering times and low furnace temperatures characterize the flash sintering process. The method can enable sintering of compounds of lithium since, in conventional sintering, which requires several hours at high furnace temperatures, it can become difficult to control the retention of lithium. Cubic Li6.25La3Zr2Al0.25O12 with a relative density of 96% was sintered in a few seconds in air at a furnace temperature of 850 °C. These specimens had an ionic conductivity of 0.5 mS cm−1 at room temperature, and an activation energy of 0.35 eV. Transgranular nature of the fracture surface suggests strong cohesion at grain boundaries.

Higher electric fields lower the temperature for the onset of flash. We explore the question “what can be the lowest temperature for initiating flash?”. Constant heating rate experiments at increasing electric fields reveal a surprising characteristic: the Debye temperature emerges as a the lower bound for the onset of flash. Data for flash temperature for three oxides are shown to exhibit this behavior in a universal plot.

Las lesiones dentales no cariosas, como los defectos de desarrollo del esmalte (DDE) y el desgaste dental erosivo (ETW), son objeto de una intensa investigación. Este artículo tiene como objetivo brindar perspectivas sobre DDE, incluida la fluorosis dental y la hipomineralización de incisivos molares (MIH), y ETW, presentando datos epidemiológicos de las Américas y aspectos de diagnóstico asociados. Además, es importante presentar evidencia para guiar el proceso de evaluación clínica, apoyando las decisiones de manejo de los clínicos hacia una mejor salud bucal de sus pacientes. El aumento general en la prevalencia mundial de lesiones no cariosas discutidas en este documento puede reflejar la necesidad de cambios en la percepción. Aunque el número de publicaciones relacionadas con estas condiciones ha ido en aumento en los últimos años, todavía existe la necesidad de concienciación sobre el diagnóstico clínico y el manejo para incluir estas condiciones en la práctica odontológica de rutina. Además, es importante brindar recomendaciones para criterios de evaluación clínica estandarizados, mejorando el proceso y ayudando a la adherencia de los clínicos. En este sentido, este trabajo discute los índices más comúnmente implementados para cada condición. Así, a pesar de la amplia gama de índices diagnósticos, se propone que BEWE sea el índice recomendado para la evaluación de ETW, los índices de Dean o Thylstrup & Fejerskov para fluorosis y preferiblemente los criterios EAPD (o índice DDE modificado) para MIH. En general, las lesiones no cariosas son una preocupación creciente, y es importante implementar medidas preventivas que controlen su gravedad y progresión, y un diagnóstico preciso por parte del odontólogo. Non-carious dental lesions such as developmental defects of enamel (DDE) and erosive tooth wear (ETW) are the subject of intensive research. This paper aims to give perspectives on both DDE, including dental fluorosis and molar incisor hypomineralization (MIH), and ETW, presenting epidemiological data from the Americas and associated diagnostic aspects. Besides, it is important to present evidence to guide the clinical assessment process, supporting the clinicians' management decisions towards better oral health of their patients. The overall increase in the worldwide prevalence of non-carious lesions discussed in this this paper may reflect the need of perceptual changes. Although the number of publications related to these conditions has been increasing in the last years, there is still a need for clinical diagnostic and management awareness to include these conditions in routine dental practice. Besides, it is important to provide recommendations for standardized clinical assessment criteria, improving the process and helping clinicians' adherence. In this sense, this paper discusses the most commonly implemented indices for each condition. Thus, despite the wide range of diagnostic indices, BEWE is proposed to be the index recommended for ETW assessment, Dean or Thylstrup & Fejerskov indices for fluorosis and preferably the EAPD criteria (or modified DDE index) for MIH. Overall, non-carious lesions are a growing concern, and it is important to implement preventive measures that control their severity and progression, and accurate diagnosis by the dental clinician.

We discuss the Arrhenius behavior of electrical conductivity σ during flash sintering of 3 mol% yttria stabilized zirconia (3YSZ). In situ x-ray diffraction is used to determine sample temperature. Sintering contribution to σ is excluded by investigating the flash event on a dense ceramic. We show that total conductivity follows an Arrhenius-like equation in both dense and green samples, even during Stage II of flash. The non-linearity often verified during flash sintering of 3YSZ is therefore related to the furnace temperature instead of the sample temperature when building the ln(σ) vs. 1/T plots. Furthermore, we verified a change in the activation energy for conduction prior to the ignition of the flash event and discussed the possible mechanisms. For instance, the decrease in activation energy from Stage I to II in the dense sample is attributed to a contribution from electronic carriers.

Introduction: Respiratory syncytial virus (RSV) is the most common cause of acute respiratory infections in children younger than two years but also produces infection in older children and even reinfection in people of any age, a characteristic related to the existence of different infecting subtypes and genotypes. Although Colombia has established the surveillance of classical respiratory viruses, there is no information about the RSV genotypes circulating in Colombian patients. Methodology: A subgroup of 227 previously RSV positive respiratory secretion samples were taken from a nationwide surveillance study, amplified and sequenced to define the circulation pattern of RSV subtypes and genotypes during 2000-2009 period in Colombia. Results. RSV exhibited seasonal behavior with an A subtype more prevalent. Both RSV subtypes had low nucleotide variability. During the study period, the GA2 and GA5 genotypes from RSV subtype A and the BA genotype from RSV subtype B were found. Conclusion. In this report, for the first time RSV genotypes circulating in Colombia were described, this information adds valuable information about virus epidemiology helping to understand the RSV epidemic and prepare our country for the introduction of new vaccines.

Objective To design and validate a questionnaire to measure caries management based on the Capability, Opportunity, and Motivation Behavior model (COM-B) and the International Caries Classification and Management System (ICCMS™). Methods A combination of Cariology and Psychology experts developed a 79-item pool that measured the COM-B components according to the ICCMS™ caries management recommended behaviours. After face and content validation and a pilot study, two samples of Colombian dentists participated: clinicians (n = 277) and clinical-practice educators (n = 212). Results Using parallel analysis and exploratory structural equation modelling (ESEM), the questionnaire was reduced to a 47-item 5-factor instrument that demonstrated good internal consistency and validity properties, including a robust factor structure, measurement invariance across samples and high predictive validity of ICCMS™ recommended behaviours. Scales' mean scores showed that dentists were conducting recommended behaviours "most-of-the-time" (Behavior), showed high confidence in their ability to conduct these behaviours (Capability) and considered recommendations as highly relevant (Opportunity-Relevance), while their appraisals of the available resources (Opportunity-Resources) and remuneration (Motivation) were notably lower. Conclusion Overall, the findings highlight the practical utility of the COM-B ICCMS™ Questionnaire in understanding the potential antecedent variables that may explain dentists' behaviours related to caries diagnosis and management and in suggesting avenues for achieving a positive change in their behaviour.

We propose an approach for estimating the error in depth data provided by generic 3D sensors, which are modern devices capable of generating an image (RGB data) and a depth map (distance) or other similar 2.5D structure (e.g. stereo disparity) of the scene. Our approach starts capturing images of a checkerboard pattern devised for the method. Then proceed with the construction of a dense depth map using functions that generally comes with the device SDK (based on disparity or depth). The 2D processing of RGB data is performed next to find the checkerboard corners. Clouds of corner points are finally created (in 3D), over which an RMS error estimation is computed. We come up with a multi-platform system and its verification and evaluation has been done, using the development kit of the board nVIDIA Jetson TK1 with the MS Kinects v1/v2 and the Stereolabs ZED camera. So the main contribution is the error determination procedure that does not need any data set or benchmark, thus relying only on data acquired on-the-fly. With a simple checkerboard, our approach is able to determine the error for any device. Envisioned application is on 3D reconstruction for robotic vision, with a series of 3D vision sensors embarked in robots (UAV of type quadcopter and terrestrial robots) for high-precision map construction, which can be used for sensing and monitoring.

Fluoride is an element that affects teeth and bone formation in animals and humans. Though the use of systemic fluoride is an evidence-based caries preventive measure, excessive ingestion can impair tooth development, mainly the mineralization of tooth enamel, leading to a condition known as enamel fluorosis. In this study, we investigated the geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples in four endemic enamel fluorosis sentinel municipalities of the department of Huila, Colombia (Pitalito, Altamira, El Agrado and Rivera), and its possible relationship with the prevalence of enamel fluorosis in children. The concentration of fluoride in drinking water, table salt, active sediment, rock, and soil was evaluated by means of an ion selective electrode and the geochemical analyses were performed using X-ray fluorescence. Geochemical analysis revealed fluoride concentrations under 15 mg/kg in active sediment, rock and soil samples, not indicative of a significant delivery to the watersheds studied. The concentration of fluoride in table salt was found to be under the inferior limit (less than 180 μg/g) established by the Colombian regulations. Likewise, exposure doses for fluoride water intake did not exceed the recommended total dose for all ages from 6 months. Although the evidence does not point out at rocks, soils, fluoride-bearing minerals, fluoridated salt and water, the hypothesis of these elements as responsible of the current prevalence of enamel fluorosis cannot be discarded since, aqueducts might have undergone significant changes overtime.

A critical summary of Pjetursson BE, Zwahlen M, Lang NP. Quality of reporting of clinical studies to assess and compare performance of implant-supported restorations. J Clin Periodontol 2012;39(suppl 12):139-159.