Abstract: Spiking neural networks (SNNs) using time-to-first-spike (TTFS) codes, in which neurons fire at most once, are appealing for rapid and low power processing. In this theoretical paper, we focus on information coding and decoding in those networks, and introduce a new unifying mathematical framework that allows the comparison of various coding schemes. In an early proposal, called rankorder coding (ROC), neurons are maximally activated when inputs arrive in the order of their synaptic weights, thanks to a shunting inhibition mechanism that progressively desensitizes the neurons as spikes arrive. In another proposal, called NoM coding, only the first N spikes of M input neurons are propagated, and these ``first spike patterns'' can be readout by downstream neurons with homogeneous weights and no desensitization: as a result, the exact order between the first spikes does not matter. This paper also introduces a third option - ""Ranked-NoM"" (R-NoM), which combines features from both ROC and NoM coding schemes: only the first N input spikes are propagated, but their order is readout by downstream neurons thanks to inhomogeneous weights and linear desensitization. The unifying mathematical framework allows the three codes to be compared in terms of discriminability, which measures to what extent a neuron responds more strongly to its preferred input spike pattern than to random patterns. This discriminability turns out to be much higher for RNoM than for the other codes, especially in the early phase of the responses. We also argue that RNoM is much more hardware-friendly than the original ROC proposal, although NoM remains the easiest to implement in hardware because it only requires binary synapses. Resumen: Las redes neuronales de picos o potenciales de acciôn (SNN) que utilizan códigos de tiempo hasta el primer pico (TTFS), en los que las neuronas se disparan una vez como máximo, son atractivas para un procesamiento rápido y de baja potencia. En este artículo teórico, nos enfocamos en la codificación y decodificación de información en esas redes, e introducimos un nuevo marco matemático unificador que permite la comparación de varios esquemas de codificación. En una propuesta inicial, llamada codificación por orden de rango (ROC), las neuronas se activan al máximo cuando las entradas llegan en el orden de sus pesos sinápticos, gracias a un mecanismo de inhibición de derivación que insensibiliza progresivamente las neuronas a medida que llegan los picos. En otra propuesta, denominada codificación NoM, solo se propagan los primeros N picos de las M neuronas de entrada, y estos ""primeros patrones de picos"" pueden ser leídos por las ""downstream neurons"" con pesos homogéneos y sin desensibilización: como resultado, el orden exacto entre los primeros picos no importa. Este documento también presenta una tercera opción: ""Ranked-NoM"" (R-NoM), que combina características de los esquemas de codificación ROC y NoM: solo se propagan los primeros picos de entrada N, pero las neuronas posteriores leen su orden gracias a pesos no homogéneos y desensibilización lineal. El marco matemático unificador permite comparar los tres códigos en términos de discriminabilidad, que mide en qué medida una neurona responde con más fuerza a su patrón de picos de entrada preferido que a patrones aleatorios. Esta discriminabilidad resulta ser mucho mayor para R-NoM que para los otros códigos, especialmente en la fase temprana de las respuestas. También argumentamos que R-NoM es mucho más compatible con el hardware que la propuesta ROC original, aunque NoM sigue siendo el más fácil de implementar en hardware porque solo requiere sinapsis binarias.

Abstract: Background: Deep brain stimulation (DBS) surgery is a treatment in the advanced stage of Parkinson's disease (PD). Despite close follow-up, multiple evaluations, and several months of timeconsuming programming sessions, the clinical response may not be optimal in some cases. Imageguided programming (I-GP) could help optimize programming sessions with better clinical outcomes. Objective: To evaluate clinical and quality of life (QoL) outcomes with I-GP in PD patients with DBS of the subthalamic nucleus (STN) and suboptimal clinical improvement and refractory symptoms to conventional clinical programming. Methods: A prospective study in 16 patients with a diagnosis of PD with STN-DBS and remaining adverse effects or symptoms despite a clinical programming adjustment. We simulate potentially effective stimulation based on volume tissue activated (VTA) using commercially available software tools. Clinical outcomes were assessed with motor and quality of life scales. Results: The most frequent suboptimal symptom was gait disorder 33.3% (n=9), residual motor symptoms 25.9%(n=7), and speech 25.9%(n=7). Statistically significant results (p=0.001) were found after I-GP with change in the global Deep Brain Stimulation – Impairment score (41%), The 8- item version of the Parkinson's Disease Questionnaire (47%), EuroQol visual analogue scale (62%), and motor scale (24%). Conclusions: In suboptimal cases of patients with PD and STN-DBS, especially with ongoing and residual motor symptoms, I-GP could be useful to optimize the programming of DBS and improve patients' QoL.

Abstract: Context: Whether due to geopolitical instability, as in Colombia or Venezuela, global warming, or simply tourism, the movement of lowlanders to high altitudes is increasing. This population movement is accompanied by increased symptoms of physiological deconditioning, among which sleep disturbances stand out. In this scenario, napping is a counter measurement for sleep disturbances; however, its benefits or physiological changes at high altitudes have not been explored. Objective: To evaluate the physiological changes during a nap in conditions simulating high altitude. Methods: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years. Volunteers underwent an evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: FiO2 21% (NN), FiO2 14.7% (NH15) and 12.5% (NH13). Results: Compared to NN, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p <0.001). Sympathetic predominance was evident by HRV and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as EPO (~6 UI/L) and cortisol (~100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Although sleep efficiency was preserved, polysomnography showed lesser N3 and REM sleep, and periodic breathing, predominantly in men. Conclusions: although napping may have metabolic and cognitive benefits, its implementation as a counter measurement in conditions of altitudinal hypoxia should be carefully evaluated as it could increase the occurrence of sleep disturbances with consequences on autonomic, endocrine and respiratory systems. Abstract: Context: Whether due to geopolitical instability, as in Colombia or Venezuela, global warming, or simply tourism, the movement of lowlanders to high altitudes is increasing. This population movement is accompanied by increased symptoms of physiological deconditioning, among which sleep disturbances stand out. In this scenario, napping is a counter measurement for sleep disturbances; however, its benefits or physiological changes at high altitudes have not been explored. Objective: To evaluate the physiological changes during a nap in conditions simulating high altitude. Methods: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years. Volunteers underwent an evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: FiO2 21% (NN), FiO2 14.7% (NH15) and 12.5% (NH13). Results: Compared to NN, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p <0.001). Sympathetic predominance was evident by HRV and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as EPO (~6 UI/L) and cortisol (~100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Although sleep efficiency was preserved, polysomnography showed lesser N3 and REM sleep, and periodic breathing, predominantly in men. Conclusions: although napping may have metabolic and cognitive benefits, its implementation as a counter measurement in conditions of altitudinal hypoxia should be carefully evaluated as it could increase the occurrence of sleep disturbances with consequences on autonomic, endocrine and respiratory systems. Resumen: Contexto: Ya sea por inestabilidad geopolítica, como ocurre en Colombia o Venezuela, por el calentamiento global, o simplemente por turismo, cada vez el desplazamiento de nativos de bajas alturas hacia las grandes alturas es mayor. Este movimiento poblacional se acompaña de un incremento en síntomas de desacondicionamiento fisiológico dentro de los que destacan las perturbaciones del sueño. En este escenario la siesta aparece como una medida contrarreguladora para las alteraciones del sueño; sin embargo, sus beneficios o cambios fisiológicos en las grandes alturas no ha sido explorado. Objetivo: Evaluar los cambios fisiológicos durante una siesta en condiciones que simulan la altura. Metodología: Este fue un estudio piloto aleatorizado, ciego, cruzado llevado a cabo con 15 sujetos nativos de bajas alturas (8 mujeres) con una edad promedio de 29 años (D.E.=6 años). Los voluntarios fueron evaluados fisiológicamente alrededor a una siesta de aproximadamente 90 min, siendo dispuestos en una secuencia aleatoria de tres condiciones: FiO2 de 21% (NN), FiO2 de 14,7% (NH15) y de 12,5% (NH13), con un periodo de reposo entre condiciones de una semana. Resultados: Comparado con NN, los intervalor RR durante la siesta se acortaron significativamente (p < 0,001) en 57 ms (NH15) y 206 ms (NH13). El predominio simpático fue evidente por el análisis de la variabilidad de frecuencia cardiaca y los niveles aumentados de adrenalina. Concomitántemente, hubo cambios significativos en parámetros endocrinos tales como al eritropoyetina (~6 UI/L) y cortisol (~100 nmol/L) (NH13 VS. NN, p < 0,001). La evaluación cognitiva mostró cambios en la prueba de Stroop. Adicionalmente, aunque la eficiencia del sueño se preservó, los resultados polisomnográficos mostraron una disminución en el sueño profundo y MOR, y un incremento de respiración periódica, fundamentalmente en hombres. Conclusiones: aunque tomar la siesta pueda tener beneficios metabólicos y cognitivos, su implementación como contrarreguladora en condiciones de hipoxia altitudinal debe ser evaluada cuidadosamente ya que podría incrementar la aparición de perturbaciones del sueño con efectos en los sistemas autónomo, endocrino y respiratorio.

Abstract: Introduction: Children born very preterm have an immature sucking reflex at birth and are exposed to neonatal care that can impede proper palate growth. Objectives: We aimed to describe the frequency of high-arched palate and posterior crossbite at the age of 5 in children born very preterm and to identify their respective risk factors. Methods: Our study was based on the data from EPIPAGE-2, a French national prospective cohort study, and included 2,594 children born between 24- and 31-week gestation. Outcomes were high-arched palate and posterior crossbite. Multivariable models estimated by generalized estimation equations with multiple imputation were used to study the association between the potential risk factors studied and each outcome. Results: Overall, 8 % of children born very preterm had a high-arched palate and 15 % posterior crossbite. The odds of high-arched palate were increased for children with low gestational age (24–29 vs. 30–31 weeks of gestation) [adjusted odds ratio (aOR) 1.76, 95% confidence interval (CI) 1.17, 2.66], thumb-sucking habits at the age of 2 (aOR 1.53, 95% CI 1.03, 2.28), and cerebral palsy (aOR 2.18, 95% CI 1.28, 3.69). The odds of posterior crossbite were increased for children with pacifier-sucking habits at the age of 2 (aOR 1.75, 95% CI 1.30, 2.36). Conclusions: Among very preterm children, low gestational age and cerebral palsy are the specific risk factors for a high-arched palate. High-arched palate and posterior crossbite share non-nutritive sucking habits as a common risk factor. The oro-facial growth of these children should be monitored. Resumen: Introducción: Los niños que nacen muy prematuros tienen un reflejo de succión inmaduro al nacer y están expuestos a cuidados neonatales que pueden impedir el correcto crecimiento del paladar. Objetivos: Nuestro objetivo fue describir la frecuencia de paladar ojival y mordida cruzada posterior a la edad de 5 años en niños nacidos muy prematuros e identificar sus respectivos factores de riesgo. Métodos: Nuestro estudio se basó en los datos de EPIPAGE-2, un estudio de cohorte prospectivo nacional francés, e incluyó a 2 594 niños nacidos entre las semanas 24 y 31 de gestación. Los resultados fueron paladar ojival y mordida cruzada posterior. Se utilizaron modelos multivariables estimados por ecuaciones de estimación generalizadas con imputación múltiple para estudiar la asociación entre los potenciales factores de riesgo estudiados y cada desenlace. Resultados: En general, el 8% de los niños nacidos muy prematuros tenían paladar ojival y el 15% mordida cruzada posterior. Las probabilidades de paladar ojival aumentaron para niños con edad gestacional baja (24–29 vs. 30–31 semanas de gestación) [odds ratio ajustado (ORa) 1,76, intervalo de confianza (IC) del 95 % 1,17, 2,66], hábito de succión del pulgar a los 2 años (ORa 1,53, IC 95% 1,03, 2,28), y parálisis cerebral (ORa 2,18, IC 95% 1,28, 3,69). Las probabilidades de mordida cruzada posterior aumentaron para los niños con hábitos de succión del chupete a la edad de 2 años (ORa 1,75, IC del 95%: 1,30, 2,36). Conclusiones: Entre los niños muy prematuros, la baja edad gestacional y la parálisis cerebral son los factores de riesgo específicos para paladar ojival. El paladar ojival y la mordida cruzada posterior comparten hábitos de succión no nutritiva como factor de riesgo común. El crecimiento orofacial de estos niños debe ser monitoreado.

Abstract: Background: Although Latin American migrants (LAMs) are one of the fastest-growing migrant populations in England, they still face health barriers that make them unaware of their HIV status, leading to late HIV diagnosis, AIDS, and even death. Thus, this study aims to assess the differences in HIV outcomes among newly HIV-diagnosed LAMs compared to other England populations. Methods: Data on new HIV/AIDS diagnoses in the UK during the 2011-2020 period were obtained from the HIV and AIDS New Diagnoses and Deaths Database (HANDD) and the HIV and AIDS Reporting System (HARS). Potential associations between the region of birth and late HIV diagnosis, AIDS at HIV diagnosis, and mortality were analysed by logistic regression. Furthermore, a comparison between LAMs and the main populations living in the UK was examined. Lastly, a descriptive trend analysis was made. Results: From 2011 to 2020, 47,828 new HIV diagnoses were reported in the UK, with almost a third (29.2%) being late diagnoses. Over half of new diagnoses (52%) were made in migrants, LAMs representing 9.3% of those diagnoses. In general, newly diagnosed HIV LAMs are not more likely to be diagnosed late than UK residents (aRRR: 1.02; 95%CI: 0.90–1.15). However, some subgroups are more likely to be diagnosed late than their UK counterparts (e.g., 15-24 years old). Regarding AIDS and mortality, LAMs are less likely to be diagnosed with AIDS (aOR: 0.50; 95%CI: 0.35–0.71) or die by any cause (aOR: 0.29; 95%CI: 0.16–0.52) than UK residents. Finally, the number of new HIV diagnoses among LAMs increased in those ten years, but the number of late diagnoses remained nearly constant. Conclusions: Although the current HIV epidemiological situation of LAMs living in the UK is not troublesome, the expansion of the LAM population and their increasing number of new HIV diagnoses could become a public health challenge in the coming years. Therefore, to accomplish the 2030 zero HIV transmission goal, it is necessary to integrate the migrant community into future public policies and categorise them as the ‘sixth’ HIV key population in the UK.

Abstract: The cell envelope is essential for the survival and adaptation of bacteria. Bacterial membrane proteins include the major porins that mediate the influx of nutrients and several classes of antimicrobial drugs. Consequently, membrane remodelling is closely linked to antimicrobial resistance (AMR). Knowledge of bacterial membrane protein biogenesis and turnover underpins our understanding of bacterial membrane remodelling and the consequences that this process has in the evolution of AMR phenotypes. At the population level, the evolution of phenotypes is a reversible process, and we can use these insights to deploy evolutionary principles to resensitize bacteria to existing antimicrobial drugs. In our opinion, fundamental knowledge is opening a new way of thinking towards sustainable solutions to the mounting crisis in AMR. Here we discuss what is known about outer-membrane remodelling in bacteria and how the process could be targeted as a means to restore sensitivity to antimicrobial drugs. Bacteriophages are highlighted as a powerful means to exert this control over membrane remodelling but they require careful selection so as to reverse, and not exacerbate AMR phenotypes.

Abstract: Antibiotic resistance is driven by selection, but how a bacterial strain’s evolutionary history shapes drug-resistance remains an open question. Here we reconstruct the genetic and evolutionary mechanisms of carbapenem resistance in a clinical isolate of Klebsiella. A combination of short and long read sequencing, machine learning, genetic and enzymatic analyses established that this carbapenem-resistant strain carries no carbapenemase-encoding genes. Genetic reconstruction of the resistance phenotype confirmed that two distinct genetic loci are necessary for the strain to acquire carbapenem resistance. Experimental evolution of the carbapenem-resistant strains in growth conditions without the antibiotic revealed that both loci confer a significant cost, and are readily lost by de novo mutation resulting in the rapid evolution of a carbapenem-sensitive phenotype. Thus, historical contingency - a patient’s treatment history - can shape the evolution of antibiotic resistance and suggests that the strategic combinations of antibiotics could direct the evolution of low-fitness, drug-resistant genotypes.

Abstract: Objective: To describe the prevalence pattern of anemia among Indigenous children in Latin America. Methods: PRISMA guidelines were followed. Records were identified from the databases PubMed, Google Scholar, and Lilacs by two independent researchers between May and June 2021. Studies were included if the following criteria were met: a) studied Indigenous people b) was about children (from 0 to 12 years old); c) reported a prevalence estimate of anemia; d) had been conducted in any of the countries of Latin America; e) was published either in English, Portuguese, or Spanish; f) is a peer-reviewed article; and g) was published at any date. Results: Out of 2,401 unique records retrieved, 42 articles met the inclusion criteria. A total of 39 different Indigenous communities were analyzed in the articles, and in 21 of them (54.0%) child anemia was a severe public health problem (prevalence ? 40%). Those communities were the Aymara (Bolivia); Aruak, Guaraní, Kamaiurá, Karapotó, Karibe, Kaxinanuá, Ma-cro-Jê, Suruí, Terena, Xavante (Brazil); Cabécar (Costa Rica), Achuar, Aguaruna, Awajún, Urarina, Yomybato (Peru); Piaroa and Yucpa (Venezuela); and Quechua (Peru and Bolivia). Children below two years had the highest prevalence of anemia (between 16.2% and 86.1%). Among Indigenous people, risk factors for anemia include nutrition, poor living conditions, access to health services, racism, and discrimination. Bolivia and Guatemala are scarcely studied, despite having the highest proportion of Indigenous communities in Latin America. Conclusions: Anemia constitutes a poorly documented public health problem among Indigenous children in 21 Indigenous communities in Bolivia, Brazil, Colombia, Costa Rica, Ecuador, Guatemala, Mexico, and Peru. In all Indigenous communities included in this study child anemia was an issue, especially in younger children. Resumen: Objetivo: Describir el patrón de prevalencia de anemia en niños indígenas de América Latina. Métodos: Se siguieron las directrices PRISMA. Los registros fueron identificados en las bases de datos PubMed, Google Scholar y Lilacs por dos investigadores independientes entre mayo y junio de 2021. Los estudios se incluyeron si cumplían los siguientes criterios: a) estudiaban a indígenas; b) eran sobre niños (de 0 a 12 años); c) reportaban una estimación de prevalencia de anemia; d) se habían realizado en cualquiera de los países de América Latina; e) se publicaron en inglés, portugués o español; f) eran artículos revisados por pares; y g) se publicaron en cualquier fecha. Resultados: De los 2.401 registros únicos recuperados, 42 artículos cumplían los criterios de inclusión. Un total de 39 comunidades indígenas diferentes fueron analizadas en los artículos, y en 21 de ellas (54,0%) la anemia infantil era un problema grave de salud pública (prevalencia ? 40%). Esas comunidades eran aymara (Bolivia); aruak, guaraní, kamaiurá, karapotó, karibe, kaxinanuá, macro- jê, suruí, terena, xavante (Brasil); cabécar (Costa Rica), achuar, aguaruna, awajún, urarina, yomybato (Perú); piaroa y yucpa (Venezuela); y quechua (Perú y Bolivia). Los niños menores de dos años presentaban la mayor prevalencia de anemia (entre el 16,2% y el 86,1%). Entre los indígenas, los factores de riesgo de la anemia son la nutrición, las malas condiciones de vida, el acceso a los servicios sanitarios, el racismo y la discriminación. Bolivia y Guatemala están escasamente estudiados, a pesar de tener la mayor proporción de comunidades indígenas de América Latina. Conclusiones: La anemia constituye un problema de salud pública poco documentado entre los niños indígenas de 21 comunidades indígenas de Bolivia, Brasil, Colombia, Costa Rica, Ecuador, Guatemala, México y Perú. En todas las comunidades indígenas incluidas en este estudio, la anemia infantil era un problema, especialmente en los niños más pequeños.

Abstract: Objective: Intestinal parasitic infections (IPIs) are a public health challenge in developing countries such as Colombia, causing anaemia and delayed growth and development in children. We aimed to estimate the geographical and prevalence trend of IPIs in the last 30years in school and preschool children in Colombia. Methods: We conducted a systematic review and meta-analysis. We identified potential manuscripts through PubMed, EMBASE, Web of Science, LILACS, Scielo and Google Scholar on the IPIs prevalence in school and preschool children in Colombia. Articles included in the qualitative analysis were published between 1990 and 2020 in English or Spanish and met the inclusion criteria. Subsequently, a random-effects meta-analysis, a meta-regression and a trend analysis were performed. Results: We identified 2292 articles; 109 were included in the qualitative review, and 79 articles were included in the meta-analysis. The estimated IPI prevalence was 55% (95% CI: 48–63). By age group, the prevalence in preschool children was 37% (95% CI: 26–49) and 66% (95% CI: 52–78) in schoolchildren. The prevalence by region was heterogeneous, with the Amazon being the highest (69%) and the Santanderes the lowest (28%). In the last 20years, the prevalence of helminthiasis has decreased (from 64.66% in 1990–1995 to 22.09% in 2016–2020). Conclusion: The prevalence of IPIs is high (>30%) in three of the seven regions in Colombia. Biannual administration of mass deworming in schoolchildren is recommended in the Amazon region. Public policies aiming to control IPIs should be reinforced. Further prevalence studies should include Cesar, Guaviare, Vichada and Vaupés, where the epidemiology of IPIs is unknown. Resumen: Objetivo: Las infecciones parasitarias intestinales (IPIs) son un desafío para la salud pública en los países en desarrollo como Colombia, ya que causan anemia y retraso en el crecimiento y desarrollo de los niños. El objetivo de este estudio fue estimar la tendencia de la prevalencia y la distribución geográfica de las IPIs en niños en edad escolar y preescolar en Colombia en los últimos 30 años. Métodos: Se llevó a cabo una revisión sistemática y un metaanálisis. Se identificaron estudios potenciales a través de PubMed, EMBASE, Web of Science, LILACS, Scielo y Google Scholar cuyo objetivo era estimar la prevalencia de las IPIs en niños en edad escolar y preescolar en Colombia. Se incluyeron artículos publicados entre 1990 y 2020, tanto en inglés como en español, que cumplieran con los criterios de inclusión. Posteriormente, se realizó un metaanálisis de efectos aleatorios, una meta-regresión y un análisis de tendencias. Resultados: Identificamos 2,292 artículos; 109 se incluyeron en la revisión cualitativa y 79 en el metaanálisis. La prevalencia estimada de las IPIs fue del 55% (IC del 95%: 48-63%). Según el grupo de edad, la prevalencia en niños preescolares fue del 37% (IC del 95%: 26-49%), y en niños en edad escolar fue del 66% (IC del 95%: 52-78%). La prevalencia por región fue heterogénea, siendo el departamento del Amazonas donde se ubicó la prevalencia más alta (69%) y los Santanderes la más baja (28%). En los últimos 20 años, la prevalencia de helmintiasis ha disminuido del 64.66% en 1990-1995 al 22.09% en 2016-2020. Conclusión: La prevalencia de las IPIs es alta (>30%) en tres de las siete regiones de Colombia. Se recomienda la administración bianual masiva de antiparasitarios en niños en edad escolar en la región del Amazonas. Las políticas públicas destinadas a controlar las IPIs deben reforzarse. Futuros estudios de prevalencia deben incluir a los departamentos de Cesar, Guaviare, Vichada y Vaupés, ya que son departamentos donde la epidemiología de las IPIs es desconocida.

Abstract: The aim of this in vitro study was to evaluate the wear and surface hardness of nine materials for conventional manufacturing, subtractive milling, and 3D printing of occlusal splints, as well as to evaluate the differences in wear and surface hardness between rigid and flexible 3D-printed occlusal splint materials. Two-body wear and Vickers hardness tests were performed. The vertical wear depth and Vickers hardness values were statistically analyzed. Vertical wear depth and surface hardness values were statistically significant among the investigated materials (p<0.05). The lowest vertical wear depth was observed for the heat-cured resin (27.5±2.4 ?m), PMMA-based milled material (30.5±2.8 ?m), and autopolymerizing resin (36.7±6.3 ?m), with no statistical difference (p<0.05). Flexible 3D-printed and CAD-CAM milled polycarbonate-based splint materials displayed lower surface hardness and higher wear than the PMMA-based materials. PMMA-based splint materials displayed the most consistent surface hardness and wear resistance regardless of the manufacturing technology. Resumen: El objetivo de este estudio in vitro fue evaluar el desgaste y la dureza superficial de nueve materiales para la fabricación convencional, fresado sustractivo e impresión 3D de férulas oclusales, así como para evaluar las diferencias en el desgaste y la dureza de la superficie entre Materiales rígidos y flexibles para férulas oclusales impresas en 3D. Se realizaron pruebas de desgaste de dos cuerpos y dureza Vickers. Se analizaron estadísticamente los valores de profundidad y dureza Vickers. Los valores de profundidad de desgaste vertical y dureza superficial fueron estadísticamente significativa entre los materiales investigados (p<0,05). La profundidad de desgaste vertical más baja se observó para la resina termocurada (27,5 ± 2,4?m), material molido a base de PMMA (30,5±2,8 ?m) y resina autopolimerizable (36,7±6,3 ?m), sin diferencia estadística (p<0,05). Los materiales flexibles para férulas a base de policarbonato impresos en 3D y fresados con CAD-CAM mostraron una menor dureza superficial y un mayor desgaste que los materiales basados en PMMA. Los materiales para férulas a base de PMMA mostraron la dureza superficial y la resistencia al desgaste más consistentes independientemente de la tecnología de fabricación.