Home / Archives / Vol. 12 No. 1 (2024) / Articles SPATIAL DISTRIBUTION OF MOLAR INCISOR HYPOMINERALIZATION (MIH) OPACITIES IN FIRST PERMANENT MOLARS

Aim: To evaluate the spatial distribution of MIH opacities in first permanent molars (FPM). Materials and methods: an analysis of intraoral photographs of FPM with demarcated MIH opacities was conducted. The presence of opacity was computed in a digital matrix, discriminating the anatomical regions of the FPM surfaces. The frequencies of distribution of the opacities were descriptively analyzed through 227 FPM digital images of 89 children built in GIMP and Python and by Spearman correlation (= 0,05). Results: the occlusal surface was the most affected one (94% to 100%). In the upper FPM, the palatine surface was the second most affected one (84%-91%). In the lower FPM, the vestibular surface was the second most affected one (85%-80%). A similar pattern of opacity distribution was observed in the contralateral teeth. On smooth surfaces, opacities were more frequent in the regions closer to the occlusal surface than to the cervical one. Conclusion: MIH opacities were mostly present on occlusal, vestibular, and lingual/palatine surfaces, respectively. There is a possibility that the occurrences are in accordance with the chronology of dental formation.

Network meta-analysis of pembrolizumab as monotherapy and in combination with chemotherapy for first-line treatment of recurrent or metastatic head and neck squamous cell carcinoma / Metanálise em rede comparativa de pembrolizumabe como monoterapia e em combinação com quimioterapia para tratamento de primeira linha de carcinoma de células escamosas da cabeça e pescoço recorrente ou metastático

Pembrolizumab monotherapy or in combination with chemotherapy is approved as first-line treatment in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) based on improved overall survival (OS) versus EXTREME regimen in the KEYNOTE-048 trial. The clinical outcomes of pembrolizumab were compared with other recommended first-line treatments in R/M HNSCC in this study through a Bayesian network meta-analysis. A systematic literature review was conducted in July 2022, from which six trials that matched the KEYNOTE-048 patient eligibility criteria were included in the network. The OS and progression-free survival (PFS) outcomes were compared in the approved pembrolizumab indication (i.e., total population for pembrolizumab in combination with chemotherapy and combined positive score [CPS] ≥ 1 population for pembrolizumab monotherapy). A significant OS improvement was observed for pembrolizumab in combination with chemotherapy and pembrolizumab monotherapy versus EXTREME regimen (hazard ratio, 95% credible interval: 0.72, 0.60-0.86; 0.73, 0.60-0.88), platinum+5- FU (0.58, 0.43-0.76; 0.58, 0.44-0.78), and platinum+paclitaxel (0.53, 0.35-0.79; 0.53, 0.35-0.81), respectively. A non-significant numeric trend in OS improvement was observed versus the TPEx regimen. PFS was comparable with most first-line treatments and was improved versus platinum+5-FU (0.48, 0.36-0.64; 0.59, 0.45-0.79). Additional analyses in higher CPS subgroups also showed consistent results. Overall, our study results showed an improvement in OS outcomes versus alternative first-line treatments, consistent with the findings of the KEYNOTE-048 trial. These data support using pembrolizumab as a suitable firstline treatment option in R/M HNSCC.

Pembrolizumabe em monoterapia ou em combinação com quimioterapia é aprovado como tratamento de primeira linha em carcinoma de células escamosas recorrente/metastático de cabeça e pescoço (CECCP R/M) com base na melhora da sobrevida global (OS), em comparação com o esquema EXTREME no estudo KEYNOTE-048. Esse estudo comparou os resultados clínicos de pembrolizumabe com outros tratamentos recomendados de primeira linha em CECCP R/M por meio de uma metanálise de rede bayesiana. Uma revisão sistemática da literatura foi conduzida em julho de 2022, a partir da qual seis ensaios clínicos que atendiam aos critérios de elegibilidade de pacientes do KEYNOTE-048 foram incluídos na rede. Os desfechos de OS e sobrevida livre de progressão (PFS) foram comparados na indicação de pembrolizumabe (população total para pembrolizumabe em combinação com quimioterapia e população com escore positivo combinado [CPS] ≥ 1 em monoterapia com pembrolizumabe). Foi observada melhora significativa na OS para pembrolizumabe em combinação com quimioterapia e monoterapia com pembrolizumabe versus o esquema EXTREME (razão de risco, intervalo de confiança de 95%: 0,72, 0,60-0,86; 0,73, 0,60-0,88), platina+5-FU (0,58, 0,43-0,76; 0,58, 0,44-0,78) e platina+paclitaxel (0,53, 0,35-0,79; 0,53, 0,35-0,81), respectivamente. Uma tendência numérica não significativa de melhoria na OS foi observada em relação ao esquema TPEx. A PFS foi comparável com a maioria dos tratamentos de primeira linha e melhor em relação à platina+5-FU (0,48, 0,36-0,64; 0,59, 0,45-0,79). Análises adicionais em subgrupos com CPS mais elevado também mostraram resultados consistentes. No geral, os resultados de nosso estudo mostraram melhora nos desfechos de OS em comparação aos tratamentos de primeira linha alternativos, consistentes com os achados do estudo KEYNOTE-048. Esses dados apoiam o uso de pembrolizumabe como opção de tratamento em primeira linha em pacientes com CECCP R/M.

Costo y porcentaje de gasto en salud por COVID-19 en primer nivel de atención / Cost and percentage of health spending by COVID-19 at the first level of care

Antecedentes. Ante la pandemia de COVID-19 el sistema de salud reasignó recursos económicos para la atención. Objetivo. Determinar el costo de la atención y el porcentaje del gasto en salud por COVID-19 en una unidad de medicina familiar de primer nivel de atención. Metodología. Estudio de costo y porcentaje de gasto en COVID-19 en una unidad de primer nivel de atención. Se identificaron los servicios generales y finales, para construir el costo fijo se utilizó la técnica de tiempos y movimientos, se identificaron el total de partidas presupuestales ejercidas en la unidad médica para cada uno de los servicios, para desagregar el gasto de los servicios generales a los finales se construyeron ponderadores. El costo variable se realizó con la técnica consenso de expertos y microcosteo. El costo promedio se relacionó con la productividad por servicio y con el total de pacientes atendidos por COVID-19, el resultado se relacionó con el presupuesto ejercido de la unidad. Resultados. El costo anual de la atención de COVID-19 en módulo respiratorio fue 158.597,25 dólares americanos, en medicina familiar fue 192.549,36 dólares americanos, el costo total ejercido en el año 2021 para atención de SARS COV 2 en una unidad de primera atención fue 351.146,61 dólares americanos. Esta cantidad representa el 9,6 % del gasto en salud. Conclusión. El costo en atención de COVID-19 y el porcentaje del gasto en salud en primer nivel de atención es elevado (AU)

Background. In the COVID-19 pandemic, the health system reallocated financial resources for care. Objetive. To determine the cost of care and the percentage of health spending due to COVID-19 in a first level care family medicine unit. Metodology. Study of the cost and percentage of spending on COVID-19 in a first-level care unit. The general and final services were identified, to construct the fixed cost, the technique of times and movements was used, the total budget items exercised in the medical unit for each of the services were identified, to disaggregate the expense of general services to the endings were constructed weights. Variable costing was performed using the expert consensus technique and microcosting. The average cost was related to productivity per service and to the total number of patients treated for COVID-19, the result was related to the budget used by the unit. Results. The annual cost of COVID-19 care in the respiratory module was 158.597,25 US dollars, in family medicine it was 192.549,36 US dollars, the total cost incurred in 2021 for SARS COV 2 care in a unit of first attention was 351.146,61 US dollars. This amount represents 9,6% of health spending. Conclusion. The cost of COVID-19 care and the percentage of health spending at the first level of care is high (AU)

Eloísa Díaz en el Primer Congreso Latinoamericano de Medicina, Santiago 1901 / Eloísa Díaz in the First Latin American Congress of Medicine, Santiago 1901

Revisando el segundo volumen de actas del Primer Congreso Latinoamericano de Medicina, reunido en Santiago los nueve primeros días del siglo XX, encontramos una conferencia de Eloísa Díaz, primera mujer chilena y latinoamericana en graduarse de médico, pese a la discriminación sufrida, que la obligó incluso a asistir a clases acompañada por su madre. Se analiza tanto esta conferencia sobre la organización del servicio médico escolar, como la introducción a su tesis de grado, y de paso las presentaciones de otros médicos participantes, haciendo hincapié en la patología infecciosa discutida y en su lenguaje verboso y florido.

Analyzing the second volume of proceedings of the First Latin American Congress of Medicine held in Santiago on the first nine days of the twentieth century, we found a lecture by Eloísa Díaz, the first Chilean and Latin American woman to graduate as a doctor, despite the discrimination she suffered, which even forced her to attend classes accompanied by her mother. This conference on the school medical service is analyzed, as well as the introduction to her degree thesis, and incidentally the presentations of other participating doctors, emphasizing the infectious pathology discussed and its verbose and flowery language.

Natural canal deviation and dentin thickness of mesial root canals of mandibular first molars assessed by microcomputed tomography

Abstract The aim of this study was to assess the centralization and dentin thickness of mesial root canals of the first mandibular molars by microcomputed tomography (micro-CT). Material and methods: Ninety-nine mandibular molars of Vertucci's type IV canals were scanned by micro-CT. The mesiodistal deviation and centroid were assessed, in both mesiobuccal (MB) and mesiolingual (ML) canals, for the apical 4mm and the full canal length. Results: The dentin thickness was similar for both MB and ML canals. The narrowest thickness was in the distal wall of an MB canal (0.07mm), while the widest was found in the mesial wall of an MB canal (2.46mm). In centroid analysis, both the MB and ML canals exhibited deviations when compared to the root centroid, along the full canal length and the apical 4mm. For the MB canal, the mean deviation was 0.83mm (0.02 mm-2.30 mm) for the full canal and 0.18mm (0.01 mm-1.01 mm) for apical 4mm. Similarly, for the ML canal, the mean deviation measured 0.83 mm (0.05mm-3.99mm) for the full canal and 0.21 mm (0.01mm-1.01mm) for the apical 4 mm. Overall, deviations were observed towards the mesial of the roots, with 69% for MB and 57% for ML canals for the full canal, and 51% for MB canals within the 4 mm. The exception was the ML canal, which exhibited a higher deviation towards distal in the apical 4mm, accounting for 52% of cases. The dentin thickness was consistent between the mesial canals of mandibular molars. However, there is no centrality of mesial canals in their roots, with frequent deviation to mesial.

Resumo O objetivo deste trabalho foi avaliar a centralização e a espessura da dentina dos canais radiculares mesiais de primeiros molares inferiores por meio de microtomografia computadorizada (micro-CT). Material e métodos: Noventa e nove molares inferiores com canais tipo IV de Vertucci foram escaneados por micro-TC. O desvio mesiodistal e o centroide foram avaliados para os canais mesiovestibular (MB) e mesiolingual (ML), nos 4mm apicais e em todo o comprimento do canal. Resultados: A espessura da dentina foi semelhante para os canais MB e ML. A espessura mais estreita foi encontrada na parede distal de um canal MB (0,07mm), enquanto a mais larga foi encontrada na parede mesial de um canal MB (2,46mm). Na análise centroide, tanto o canal MB quanto o ML exibiram desvios quando comparados ao centroide da raiz, ao longo de todo o comprimento do canal e nos 4 mm apicais. Para o canal MB, o desvio médio foi de 0,83mm (0,02mm-2,30mm) para canal inteiro e 0,18mm (0,01mm-1,01mm) para o apical de 4mm. Da mesma forma, para o canal ML, o desvio médio mediu 0,83 mm (0,05 mm-3,99 mm) para o canal inteiro e 0,21 mm (0,01 mm-1,01 mm) para os 4 mm apicais. No geral, foram observados desvios em direção mesial das raízes, sendo 69% para canais MB e 57% para canais ML para canal inteiro, e 51% para canais MB dentro dos 4 mm. A exceção foi o canal ML, que apresentou maior desvio para distal nos 4mm apicais, representando 52% dos casos. A espessura da dentina foi consistente entre os canais mesiais dos molares inferiores. Entretanto, não há centralidade dos canais mesiais em suas raízes, com frequente desvio para mesial.

A importância do ensino e aprendizagem de técnicas de primeiros socorros para leigos: revisão integrativa / The importance of teaching and learning first aid techniques for laypersons: integrative review / La importancia de la enseñanza y el aprendizaje de las técnicas de primeros auxilios para los profanos: revisión integradora

Objetivo: analisar, a importância do ensino e aprendizagem sobre técnicas de Primeiros Socorros para leigos. Métodos: revisão integrativa nas bases de dados LILACS, MEDLINE via PUBMED, BDENF, CINAHL, SCOPUS e biblioteca Cochrane, sem recorte de tempo. Os descritores utilizados foram.: "Educação da População", "Educação em saúde", "Primeiros Socorros" e "Emergências", em inglês foram delimitados e cruzados os descritores.: "Population Education", "Health Education", "First aid" e "Emergencies" os operadores booleanos AND e OR. A amostra foi composta por 11 artigos. Resultados: capacitações em primeiros socorros têm um impacto significativo principalmente ao se aplicar questionários pré e pós-intervenções, pois os erros cometidos anteriormente já se transformavam em acertos. Conclusão: as intervenções educativas realizadas em escolas e comunidades levam a propagação de conhecimento e aprendizagem, podendo assim tangenciar a formação de multiplicadores, resultando em uma sociedade informada.

Objective: to analyze, the importance of teaching and learning about First Aid techniques for lay people. Methods: integrative review in the databases LILACS, MEDLINE via PUBMED, BDENF, CINAHL, SCOPUS and Cochrane library, without a time cut. The descriptors used were: "Population Education", "Health Education", "First Aid" and "Emergencies", in English the Boolean operators AND and OR were delimited and crossed the descriptors: "Population Education", "Health Education", "First aid" and "Emergencies". The sample consisted of 11 articles. Results: first aid trainings have a significant impact mainly when applying pre- and post-intervention questionnaires, because the mistakes previously made were already transformed into successes. Conclusion: the educational interventions carried out in schools and communities lead to the propagation of knowledge and learning, thus being able to tangent the formation of multipliers, resulting in an informed society.

Objetivos:analizar, la importancia de la enseñanza y el aprendizaje de las técnicas de Primeros Auxilios para los profanos. Métodos:revisión integradora en las bases de datos LILACS, MEDLINE a través de PUBMED, BDENF, CINAHL, SCOPUS y biblioteca Cochrane, sin corte de tiempo. Los descriptores utilizados fueron: "Population Education", "Health Education", "First Aid" y "Emergencies", en inglés se delimitaron y cruzaron los siguientes descriptores: "Population Education", "Health Education", "First aid" y "Emergencies" los operadores booleanos AND y OR. La muestra estaba compuesta por 11 artículos. Resultados: las formaciones en primeros auxilios tienen un impacto significativo sobre todo cuando se aplican los cuestionarios previos y posteriores a la intervención, ya que los errores cometidos anteriormente se transformaron en aciertos. Conclusión: las intervenciones educativas llevadas a cabo en las escuelas y comunidades conducen a la propagación del conocimiento y el aprendizaje, pudiendo así tangibilizar la formación de multiplicadores, dando lugar a una sociedad informada.

First-in-class small molecule drugs in 2023 / 药学学报

In 2023, drug discovery develops steadily, with improvement of small molecule drugs discovery keeps pace with biological drugs in this year. The Center for Drug Evaluation and Research of U.S. Food and Drug Administration has totally approved 55 kinds of new drugs which have significantly promotion compared to 37 new drugs approval in 2022, including 38 kinds of new molecular entities, 17 kinds of biological drugs, 5 kinds of gene therapeutics and 2 cell therapeutics. The proportion of first-in-class drugs increased steadily, with 13 small molecule first-in-class drugs and 7 biological first-in-class drugs approved this year, mostly in the fields of cancer and rare diseases. Among them, a plurality of first-initiated small molecule drugs exhibits breakthrough significance, such as the first neurokinin 3 (NK3) receptor antagonist fezolinetant, the first retinoic acid receptor (RIG-I) agonist palovarotene, the first protein kinase B (AKT) inhibitor capivasertib, the first complement factor B inhibitor iptacopan, etc. The pioneering drug has huge academic and commercial value, and has become the target of the academic and industrial circles. However, first-in-class drugs not only need new targets, new mechanisms and new molecules, but also need to comprehensively verify the causality between new targets and diseases, study the correlation between new mechanisms and drug efficacy, and explore the balance between new molecules and drug-manufacturing properties. This article analyzed the research background, development process and therapeutic application of three first-initiated small molecule drugs in this year, expecting to provide more research ideas and methods for more first-in-class drugs.

The biotin synthesis pathway in Mycobacteria tuberculosis is a new target for the development of anti-tuberculosis drugs / 药学学报

italic>Mycobacterium tuberculosis, responsible for tuberculosis (TB), remains a major health problem worldwide and is one of the infectious diseases causing increased morbidity and mortality worldwide. Biotin, namely vitamin H, is an important cofactor necessary for fatty acid biosynthesis, gluconeogenesis and amino acid metabolism in organisms including Mycobacterium tuberculosis. Due to its inability to ingestion biotin from outside, Mycobacterium tuberculosis can only obtain biotin through biotin biosynthesis. Different from the classical BioC-BioH, BioI-BioW and non-classical BioZ pathways, Mycobacterium tuberculosis synthesized biotin by "BioC-BioH(2)" pathway in the early stage. This review focuses on the unique biotin synthesis pathway of Mycobacterium tuberculosis and its key genes, especially the response of this pathway and biotin-dependent carboxylase to tuberculosis first-and second-line drugs, as well as inhibitors and natural products targeting biotin synthesis.

Meta-analysis of the efficacy of invisible orthodontic appliances for maxillary molar distalization in adult patients / 口腔疾病防治

Objective@#To evaluate the clinical efficacy of invisible orthodontic appliances without brackets for the distal movement of maxillary molars to improve the ability of orthodontists to predict treatment outcomes.@*Methods@#Web of Science, Cochrane Library, Embase, PubMed, Wanfang Database, CNKI Database, and VIP Database were searched for studies investigating the efficacy of invisible orthodontic appliances for distal movement of maxillary molars in adult patients and published from database inception to August 1, 2023. A total of three researchers screened the studies and evaluated their quality and conducted a meta-analysis of those that met quality standards.@*Results@#This study included 13 pre- and postcontrol trials with a total sample size of 281 patients. The meta-analysis revealed no significant differences in the sagittal or vertical parameters of the jawbone after treatment when compared with those before treatment (P>0.05). The displacement of the first molar was MD=-2.34, 95% CI (-2.83, -1.85); the displacement was MD=-0.95, 95% CI (-1.34, -0.56); and the inclination was MD=-2.51, 95% CI (-3.56, -1.46). There was a statistically significant difference in the change in sagittal, vertical, and axial tilt of the first molar before and after treatment. After treatment, the average adduction distance of the incisors was MD=-0.82, 95% CI (-1.54, -0.09), and the decrease in lip inclination was MD=-1.61, 95% CI (-2.86, -0.36); these values were significantly different from those before treatment (P<0.05).@*Conclusion@#Invisible orthodontic appliances can effectively move the upper molars in a distal direction and control the vertical position of the molars. When the molars move further away, there is some degree of compression and distal tilt movement, which is beneficial for patients with high angles. The sagittal movement of incisors is beneficial for improving the patient's profile.

Analysis of the current status and related factors of first aid knowledge among middle-aged and elderly residents in a community in Shanghai / 上海预防医学

ObjectiveTo investigate the current status of first aid knowledge among middle-aged and elderly residents aged 50 and above in a community in Shanghai， in order to provide reference for improving the self-rescue and mutual aid capabilities of middle-aged and elderly residents. MethodsA multi-stage stratified random sampling method was used to conduct a survey on 335 residents aged 50 and above in a community in Shanghai using a self-made survey questionnaire. The current situation and related factors of emergency knowledge level of residents aged 50 and above in the community were comprehensively analyzed. ResultsFirst aid knowledge level of 335 residents aged 50 and above was low， and the rate of high cognitive level was only 24.18%. Univariate analysis showed that male residents had a higher awareness rate than female residents （P=0.044）， while residents aged 70 and above and 60‒ had lower awareness rates than residents aged 50‒ （P<0.05）. Residents with chronic diseases had a higher awareness rate than those who did not （P=0.031）. Residents with family members suffering from chronic diseases had a higher awareness rate than those without （P<0.001）. Experience of first aid training affected residents’ awareness of first aid （P=0.003）. ConclusionThe level of first aid knowledge among middle-aged and elderly residents aged 50 and above in the community is low. Age， the presence of chronic diseases in family members， and emergency training are independent and relevant factors that affect the awareness of first aid knowledge among middle-aged and elderly residents. The government and relevant institutions should explore the establishment of a standardized emergency response training system， implement classification and grading for middle-aged and elderly groups with different characteristics， and provide targeted emergency training to strengthen their self-rescue and mutual aid capabilities and improve the success rate of pre-hospital emergency care.

Associations between lifestyle and comorbid anxiety and depression in pregnant women / 环境与职业医学

Background Anxiety and depression are common perinatal mental health issues that often occur together and can have serious negative effects on both maternal and infant health. Objective To examine the relationships between lifestyle factors and comorbid anxiety and depression (CAD) among pregnant women in Shanghai. Methods The study estimated the prevalence of CAD during the first, second, and third trimesters of pregnancy using the Self-rating Anxiety Scale (SAS) and Center for Epidemiological Studies-Depression (CES-D) based on data from the China National Birth Cohort (CNBC) embryonic-derived diseases with assisted reproductive technology (ART) sub-cohort. Information on demographics, sleep status, nutritional intake, and exercise during each trimester was collected through self-made questionnaires, the Pittsburgh Sleep Quality Index (PSQI), and the Food Frequency Questionnaire (FFQ). Lifestyle factors (such as sleep status, nutritional intake, and exercise during each trimester) were analyzed using logistic regression and generalized linear mixed models (GLMM) to determine their impacts on the prevalence of CAD (yes or no) among pregnant women. Results A total of 2876 pregnant women were included in this study. The prevalence of CAD was 10.6% (305), 3.6% (103), and 5.5% (159) in the first, second, and third trimesters of pregnancy, respectively. The logistic regression analysis revealed that poor sleep quality throughout the entire pregnancy were statistically associated with an increased prevalence of CAD, and the odds ratios (OR) with 95% confidence intervals (CI) were 2.817 (1.845, 4.301), 2.840 (1.855, 4.347), and 9.316 (5.835, 14.876) for the first, second, and third trimesters, respectively, when compared to good sleep quality. Additionally, compared to an intake frequency of 7 times per week, the frequency of egg intake ≤3 times per week in the first trimester (OR=2.025, 95%CI: 1.197, 3.425) and the frequency of egg intake of 4–6 times per week (OR=1.896, 95%CI: 1.117, 3.216) or ≤3 times per week (OR=1.906, 95%CI: 1.082, 3.357) in the third trimester were associated with an increased risk of CAD (P<0.05). Moreover, when compared to a frequency of exercise >3 times per week, never or almost never exercising in the second trimester (OR=2.218, 95%CI: 1.220, 4.035) was associated with an increased risk of CAD (P<0.05). The GLMM analysis also demonstrated a significant association between poor sleep quality, lower exercise frequency, or lower intake frequency of vegetables, eggs, or milk and an increased risk of CAD (P<0.05). Conclusion The prevalence of CAD among pregnant women in Shanghai follows a U-shaped distribution, with the highest rate occurring in early pregnancy and the lowest rate in mid-pregnancy. Factors such as poor sleep quality, inadequate intake of vegetables, eggs, or milk, and lack of exercise during pregnancy may increase the risk of CAD. Implementing lifestyle interventions during pregnancy could potentially reduce the risk of mental health problems and improve the overall health of both mothers and babies.

The Prevalence, Severity and Pattern of First Permanent Molars’ Dental Caries in Children Attending A Postgraduate Dental Hospital: A Retrospective Study

@#Introduction: First permanent molars (FPMs) erupt early and their anatomy and location leave them susceptible to dental caries. This study aimed to retrospectively determine the prevalence, severity and pattern of dental caries of FPMs and investigate their relationship if any with demographics and medical health status of the partcipants. Methods: This was a retrospective cross-sectional study. A sample of the digital case notes and radiographs of children aged 5 to 12 years who attended the only postgraduate dental hospital in Dubai were accessed. The recorded data included the children’s demographic variables and the carious status of each FPM as recorded in the notes on the initial assessment. Descriptive and statistical analyses were conducted (P<0.05). Results: A total of 2984 FPMs were obtained from the digital records of 774 children. Their mean age was 8.07 (±2.23) years and only those that met the inclusion criteria were included in the study. The prevalence of dental caries and mean Decayed Missing Filled Surfaces of FPMs, were 42% and 0.3 (±0.04), respectively. The most prevalent decayed surface was the occlusal (29.2%), followed by mesial, buccal, palatal/ lingual, distal surfaces (24.2 %; 6.6 %; 3.1 %; 2.3 %) respectively. Children with medical problems and/or special needs had a significantly higher level of caries in the buccal surfaces (12.3%) (P=0.042). Conclusion: Caries of FPMs in a sample of Dubai children studied was prevalent, especially in those with special healthcare needs, thus indicating a necessity for targeted prevention and treatment focused on these keystone teeth.

Risk assessment of nosocomial infection in patients with multiple myeloma in the first hospitalization / 公共卫生与预防医学

Objective To assess the risk of nosocomial infection in patients with multiple myeloma during their first hospitalization. Methods Totally 480 patients with multiple myeloma who were hospitalized for the first time in department of hematology of West China Hospital, Sichuan University from August 2021 to August 2022 were included, and the nosocomial infection during treatment was statistically analyzed. The patients were divided into infected group and uninfected group. The independent influencing factors of nosocomial infection were analyzed and a prediction model was established. The reliability of the prediction model was analyzed by receiver operating characteristic curve (ROC). Results The incidence rate of nosocomial infection was 31.2% among 480 patients hospitalized for the first time. There were statistically significant differences in age, ISS staging, controlling nutritional status (CONUT) score, agranulocytosis, hemoglobin, and albumin between the infected group and the uninfected group (P<0.05). Logistic multivariate regression analysis showed that age, ISS staging, CONUT score, agranulocytosis, hemoglobin level, and albumin level were all independent correlated factors of nosocomial infection in patients with multiple myeloma hospitalized for the first time (P<0.05). The area under the ROC curve (AUC), sensitivity and specificity of multivariate logistic regression prediction model were 0.88 (95%CI: 0.840-0.920), 85.00% and 76.36%, respectively. Conclusion The incidence rate of nosocomial infection is high among patients with multiple myeloma in the first hospitalization. The prediction model established according to independent correlated factors of nosocomial infection has high predictive value on the occurrence of nosocomial infection.

Characteristics of anterior segment structure in first-degree relatives of patients with primary angle-closure glaucoma / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the characteristics of anterior segment structure in first-degree relatives of patients with primary angle-closure glaucoma(PACG).METHODS: A total of 48 first-degree relatives of PACG patients aged 40-60 who were treated in the Affiliated Eye Hospital of Nanchang University from September 2020 to October 2022 were selected as the observation group. Additionally, 40 cases(40 eyes)of healthy individuals without glaucoma and family history of glaucoma at the same age group were collected as the control group. They were divided into younger group(40-49 years old)and elder group(50-60 years old). All subjects were examined with ultrasound biomicroscopy(UBM)and were measured using camera measure software. The parameters mainly included anterior chamber depth(ACD), anterior chamber area(ACA), anterior chamber width(ACW), anterior segment depth(ASD), angle open distance(AOD500), trabecular iris angle(TIA), trabecular iris area(TISA500), lens vault(LV), iris curve(IC), iris thickness(IT500), scleral ciliary process angle(SCPA), and iris ciliary process distance(ICPD).RESULTS: ACD, ACA, AOD500, TISA500 and TIA in the observation group were lower than those of the control group, and LV and IC were higher than those of the control group(all P&#x0026;#x003C;0.05). ACD, ACA, AOD500, TISA500, and TIA of the elder group were lower than those in the age-matched control group, while LV and IC were larger than those of the age-matched control group(all P&#x0026;#x003C;0.05). ACD, AOD500, TISA500, and TIA of the younger observation group were smaller than those of the age-matched control group, but LV and IC were significantly larger than those of the age-matched control group(all P&#x0026;#x003C;0.05). ACD, ACA, AOD500, TISA500 and TIA of the elder observation group were significantly lower than those of the younger observation group, and LV and IC were significantly larger than those of the younger observation group(all P&#x0026;#x003C;0.05). There was a difference in the distribution of ACD between the observation group and the control group(P&#x0026;#x003C;0.05), and the proportion of moderate to severe shallow anterior chambers was 10 times that of the control group. Correlation analysis showed that TISA500 was positively correlated with ACD and ACA, and negatively correlated with LV and IC, and TISA500 was mainly influenced by LV. IC had a positive correlation with LV and a negative correlation with ACD and ACA.CONCLUSION: First-degree relatives of PACG with normal axial length have a high risk of angle closure. The anterior segment structures of first-degree relatives of PACG are more crowded than normal individuals, and the lens forward shift may be the initial influencing factor for narrow angle.

Perception of first-order grating acuity and second-order spatial contrast sensitivity in anisometropia amblyopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the perception of first-order grating acuity and second-order spatial contrast sensitivity in patients with monocular anisometropia amblyopia.METHODS:A total of 715 children(715 eyes)diagnosed as monocular anisometropia amblyopia in our hospital from January 2018 to December 2022 were collected as amblyopia group, and 745 children(745 eyes)with normal corrected visual acuity were collected. The best corrected visual acuity(BCVA), first-order grating acuity and/or second-order spatial contrast sensitivity were measured, repectively. The perception ability of amblyopia patients to first-order grating acuity and second-order spatial contrast sensitivity were analyzed.RESULTS:There were significant differences between amblyopia group and normal control group in the perception of first-order grating acuity(11.58±6.10 vs. 20.27±3.47, P&#x0026;#x003C;0.001)and second-order spatial contrast sensitivity(0.33±0.16 vs 0.12±0.04, P&#x0026;#x003C;0.001). And there were significant differences between mild-to-moderate amblyopia and severe amblyopia patients in first-order grating acuity(12.10±6.23 vs. 8.13±3.70, P&#x0026;#x003C;0.001)and second-order spatial contrast sensitivity(0.32±0.16 vs. 0.37±0.17, P&#x0026;#x003C;0.05).CONCLUSION: The first-order and second-order visual pathway of the cerebral cortex in children with monocular anisometropia amblyopia have different degrees of damage. The injury of severe amblyopia is more serious than that of mild-to-moderate amblyopia.

Construção e validação de cartilha educativa sobre suporte básico de vida para estudantes do ensino médio / Construction and validation of an educational booklet on basic life support for high school students / Construcción y validación de carpeta educativa sobre soporte vital básico para estudiantes de secundaria

O objetivo deste estudo é construir e validar uma cartilha educativa para estudantes do ensino médio sobre Suporte Básico de Vida nas escolas. Trata-se de uma pesquisa metodológica, realizada em três etapas. Na primeira etapa foi realizada revisão bibliográfica, na segunda etapa procedeu-se a elaboração da cartilha educativa e por fim, a validação do material por especialistas. Entre os resultados destaca-se que a cartilha aborda as principais recomendações acerca da segurança do socorrista e suporte básico de vida no adulto e possui 14 páginas. Conclui-se que todos os itens da cartilha educativa obtiveram índice de validade de conteúdo maior que 0,82 conseguindo a validação.

The objective of this study is to build and validate an educational booklet for high school students about Basic Life Support in schools. This is a methodological research, carried out in three stages. In the first stage, a bibliographic review was carried out, in the second stage, the educational booklet was elaborated and, finally, the material was validated by specialists in the subject. Among the results, it is highlighted that the booklet addresses the main recommendations regarding rescuer safety and basic adult life support and has 14 pages. It was concluded that all items in the educational booklet had a content validity index greater than 0.82, achieving validation.

El objetivo de este estudio es construir y validar una cartilla educativa para estudiantes de secundaria sobre Soporte Vital Básico en las escuelas. Se trata de una investigación metodológica, realizada en tres etapas. En la primera etapa se realizó una revisión bibliográfica, en la segunda etapa se elaboró la cartilla educativa y, finalmente, el material fue validado por especialistas en el tema. Entre los resultados, se destaca que la cartilla aborda las principales recomendaciones sobre seguridad del reanimador y soporte vital básico del adulto y tiene 14 páginas. Se concluyó que todos los ítems de la cartilla educativa tuvieron un índice de validez de contenido superior a 0,82, lográndose la validación.

Conocimiento sobre primeros auxilios en estudiantes de la carrera Profesor de Educación Física de la Universidad de Tarapacá / Knowledge about first aid in students of the Professor of Physical Education career at the University of Tarapacá / Conhecimento de primeiros socorros nos alunos do curso de Professor de Educação Física da Universidade de Tarapacá, Chile

Resumen: Introducción: Evaluar el conocimiento (saber) sobre primeros auxilios (PA) en estudiantes de la carrera Profesor de Educación Física de la Universidad de Tarapacá, comparando el centro de estudios de procedencia y el género del alumnado. Metodología: Se efectuó un estudio mixto, con variables cualitativas y cuantitativas, en el que se indagó sobre el conocimiento en primeros auxilios en estudiantes de la carrera Profesor de Educación Física de la Universidad de Tarapacá. Se evaluó a 169 estudiantes, 99 con ingresos procedentes del Centro de Formación Técnica Tarapacá y 70 con incorporación a partir de la Prueba de Selección Universitaria. Se aplicó una encuesta, validada por criterio experto, que investigó sobre el conocimiento (saber) en relación con primeros auxilios. Se utilizó un pretest y, posteriormente, se intervino con un curso formativo teórico-práctico en primeros auxilios. Al finalizar el curso, se efectuó un postest, que tuvo como finalidad comprobar los conocimientos adquiridos sobre primeros auxilios. Resultados: Se observó que los hombres mostraron mayor conocimiento durante el pretest y el postest, con un 95.1 % y un 100 %, respectivamente, mientras que las mujeres registraron un 75 % en el pretest y 90.1 % en el postest. Por otro lado, el alumnado procedente del Centro de Formación Técnica mantuvo indicadores superiores en ambos análisis. Conclusiones: Los conocimientos adquiridos en enseñanza intermedia, así como la realización de cursos iniciales relacionados con primeros auxilios, favorecen la preparación del futuro profesorado de educación física, lo que conlleva un mejor accionar ante situaciones de emergencia, tanto en las escuelas como en la vida cotidiana.

Abstract: Introduction: To evaluate the knowledge (knowledge) about first aid (PA) in students of the Physical Education Professor career at the University of Tarapacá, comparing the study center of origin and the gender of the students. Methodology: A mixed study was carried out, with qualitative and quantitative variables, inquiring about knowledge in first aid in students of the Physical Education Professor Career, University of Tarapacá. 169 students were evaluated, 99 with income from the Tarapacá Technical Training Center and 70 incorporated from the University Selection Test. A survey was applied, validated by expert criteria, inquiring about knowledge (knowledge) in relation to first aid. A pre-test was used and subsequently a theoretical-practical training course in first aid was intervened. At the end of the course, a post-test was carried out, which the purpose of verifying the knowledge had acquired about first aid. Results: It was observed that the men showed greater knowledge during the pre-test and the post-test, with 95.1% and 100% respectively, while the women showed 75% in the pre-test and 90.1% in the post-test. On the other hand, students from the Technical Training Center maintained higher indicators in both analyses. Conclusions: The knowledge acquired in intermediate education, as well as the completion of initial courses related to first aid, favor the preparation of future Physical Education teachers, which leads to better actions in emergency situations, both in schools and in life everyday.

Resumo: Introdução: Avaliar o conhecimento sobre primeiros socorros (PS) dos estudantes da carreira de Professor de Educação Física da Universidade de Tarapacá, Chile, comparando o centro de estudos de origem e o gênero dos estudantes. Metodologia: Foi realizado um estudo misto, com variáveis qualitativas e quantitativas, no qual foram investigados conhecimentos sobre primeiros socorros em estudantes da carreira de Professor de Educação Física da Universidade de Tarapacá. O estudo avaliou 169 alunos, 99 provenientes do Centro de Treinamento Técnico de Tarapacá, e 70 que passaram no exame de admissão. Foi realizada uma pesquisa validada por especialistas, perguntando sobre os conhecimentos em relação aos primeiros socorros. Um pré-teste foi aplicado e, posteriormente, um curso teórico-prático de treinamento em primeiros socorros foi ministrado. Ao final do curso, foi realizado um pós-teste com o objetivo de verificar os conhecimentos adquiridos nos primeiros socorros. Resultados: Foi observado que os homens mostraram maiores conhecimentos durante o pré-teste e o pós-teste, com 95,1% e 100% respectivamente, enquanto as mulheres mostraram 75% no pré-teste e 90,1% no pós-teste. Por outro lado, os estudantes do Centro de Treinamento Técnico mantiveram indicadores mais elevados em ambas as análises. Conclusões: Os conhecimentos adquiridos no ensino médio, assim como a conclusão dos cursos iniciais de primeiros socorros, favorecem a preparação dos futuros professores de Educação Física, o que leva a melhores ações em situações de emergência, tanto nas escolas como na vida cotidiana.

Caracterización de los adultos mayores con cáncer colorrectal en la comunidad / Characterization of Community Older Adults with Colorectal Cancer

Introducción: El cáncer colorrectal es la neoplasia más frecuente del sistema digestivo en los adultos mayores. En Cuba es un problema de salud de primer orden por su elevada incidencia y mortalidad, que constituye la tercera causa de muerte. Objetivo: Caracterizar a los adultos mayores con cáncer colorrectal en el Policlínico Sur de Sancti Spíritus. Métodos: Investigación de tipo descriptiva en el Policlínico Sur del municipio y la provincia de Sancti Spíritus de enero a marzo del 2019. Muestra intencional de 127 adultos mayores, pertenecientes a consultorios urbanos. Las variables: edad, sexo, escolaridad, estadio del cáncer colorrectal al diagnóstico, estado de salud, comorbilidades, capacidad y percepción del autocuidado y supervivencia. Para determinar el estadio al diagnóstico se utilizó la clasificación anatomoclínica. La comorbilidad se midió mediante el índice de Chalson mientras que para medir la capacidad y percepción del autocuidado se empleó el Test de CYPAC-AM. Resultados: En la caracterización de la muestra predominaron las mujeres, el grupo de edad entre 70 y 79 años y la escolaridad de secundaria básica. El estadio II, con un mal estado de salud y la inadecuada percepción de autocuidado, fue mayoritario. La comorbilidad fue moderada con una supervivencia entre 40 a 60 meses. Conclusiones: La adecuada caracterización de los adultos mayores con cáncer colorrectal en la comunidad posibilita trazar estrategias dirigidas a la mejora del autocuidado y el estado de salud de los gerontes desde el primer nivel de atención(AU)

Introduction: Colorectal cancer is the most frequent neoplasm of the digestive system in older adults. In Cuba, it is a highly significant health problem due to its high incidence and mortality, also being the third cause of death. Objective: To characterize older adults with colorectal cancer at Policlínico Sur of Sancti Spíritus. Methods: A descriptive research was carried out in Policlínico Sur of Sancti Spíritus Municipality and Province from January to March 2019. The intentional sample was made up of 127 older adults, belonging to urban family medical offices. The variables were age, sex, school level, stage of colorectal cancer at diagnosis, health status, comorbidities, selfcare capacity and perception, and survival. The anatomoclinical classification was used to determine the stage at diagnosis. Comorbidity was measured using the Chalson index, while the CYPAC-AM (older adult selfcare capacity and perception) test was used to measure selfcare capacity and perception. Results: In the characterization of the sample, there was a predominance of women, the age group between 70 and 79 years, and the junior high school level. Stage II prevailed, together with poor health status and inadequate selfcare perception. Comorbidity was moderate, with survival between 40 to 60 months. Conclusions: The adequate characterization of older adults with colorectal cancer in the community makes it possible to outline strategies aimed at improving selfcare and their health status from the first level of care(AU)

La toma de decisión emocional afecta negativamente la eficacia de la primera ayuda psicológica, más allá del perfil psicológico del rescatista / Emotional Decision Making Negatively Affects the Effectiveness of Psychological First Aid, Irrespective the Rescuer's Psychological Profile / A tomada de decisão emocional afeta negativamente a eficácia dos primeiros auxílios psicológicos, além do perfil psicológico do socorrista

El protocolo de primera ayuda psicológica basado en el modelo de las 4 C (PAP-4C) establece pautas para brindar apoyo y rescatar a individuos afectados en el lugar y momentos inmediatos posteriores a un desastre. Los objetivos de esta investigación fueron estudiar los efectos de la toma de decisión y el entrenamiento presencial breve en la PAP-4C sobre la propensión al comportamiento eficaz de rescate según ese modelo, evaluada una semana después de la capacitación recibida; e identificar otras variables psicológicas que se vinculan con dicha propensión. Para este estudio, se adoptó un enfoque explicativo, que involucró la implementación de un diseño experimental factorial 2x2, con los factores toma de decisión y entrenamiento presencial breve en la PAP-4C, en una muestra de 175 estudiantes universitarios de una academia militar sin entrenamiento previo en rescate en situaciones de desastre. Los resultados de un ancova mostraron que la toma de decisión basada en la emoción perjudica la propensión al comportamiento eficaz en la PAP-4C en comparación con una toma de decisiones basada en la racionalidad, luego de controlar estadísticamente a las covariables. Con relación a la identificación de estas, una serie de características psicológicas se habían mostrado asociadas con la propensión al comportamiento eficaz de rescate. En este sentido, se habían hallado correlaciones positivas con tenacidad, honestidad, apertura, jovialidad, agradabilidad, la atracción afectiva hacia los demás y la toma de la perspectiva del otro. Además, se habían hallado asociaciones positivas con las estrategias de afrontamiento cognitivo dirigido a cambiar la situación, y cognitivo y conductual motor para reducir la emoción. Finalmente, se habían encontrado también asociaciones negativas con la aversión afectiva hacia los demás y el afrontamiento evitativo. En conclusión, por una parte, los resultados de este estudio apuntan a mostrar la importancia de que los líderes de grupos de rescate indiquen a los rescatistas que, cuando realizan la tarea del rescate de personas afectadas por desastres, eviten tomar decisiones emocionales. Por otra parte, los resultados también ofrecen orientación para la selección de personal sin experiencia previa en la asistencia en situaciones de desastre, ya que se identificó una amplia serie de variables psicológicas asociadas a la propensión al comportamiento eficaz en la PAP-4C. En suma, esta investigación proporciona un valioso aporte al campo de la asistencia psicológica en situaciones de crisis, al identificar factores y variables psicológicas que podrían influir en los comportamientos de los rescatistas no profesionales y sin experiencia previa cuando se debe rescatar y brindar apoyo psicológico a personas afectadas por un desastre.

The psychological first aid protocol based on the 4 Cs model (PAP-4C) establishes guidelines for providing support and rescue to affected individuals at the scene and in the immediate aftermath of a disaster. The ob-jectives of this research were to study the effects of decision making and brief training in the PAP-4C on the propensity for effective rescue behaviour according to that model, assessed one week after the training received; and to identify other psychological variables that are linked to that propensity. For this study, an explanatory approach was adopted, involving the implementation of a 2x2 factorial experimental design, with the factors decision making and brief face-to-face training in the PAP-4C, in a sample of 175 university students from a military academy with no previous training in disaster rescue. The results of an ancova showed that emotionbased decision making impaired the propensity for effective behaviour in PAP-4C compared to rationality-based decision making, after statistically controlling for covariates. In relation to the identification of covariates, a number of psychological characteristics had been shown to be associated with the propensity for efficient rescue behaviour. In this regard, positive correlations were found with tenacity, honesty, openness to experience, cheerfulness, agreeableness, affective attraction to the other and taking the other's perspective. In addition, positive associations were found with cognitive coping strategies aimed at changing the situation, and cognitive and behavioural motor coping strategies aimed at reducing the emotion. Finally, negative associations were also found with an affective aversion towards the other and avoidant coping. In conclusion, on the one hand, the results of this study aim to show the importance of rescue team leaders instructing rescuers to avoid making emotional decisions when carrying out rescuing disaster affected people. On the other hand, the results provide guidance for the selection of personnel with no previous expe-rience in disaster relief, as a wide range of psycho-logical variables associated with the propensity for effective behaviour in PAP-4C were identified. In sum, this research provides a valuable contribution to the field of psychological assistance in crisis situations by identifying psychological factors and variables that may influence the behaviours of non-professional and inexperienced rescuers when rescuing and providing psychological support to disaster-affected people.

O protocolo de primeiros auxílios psicológicos baseado no modelo 4 C (PAP-4C) estabelece diretrizes para fornecer apoio e resgatar indivíduos afetados no local e imediatamente após um desastre. Os objetivos desta pesquisa foram estudar os efeitos da tomada de decisão e do breve treinamento presencial no PAP-4C sobre a propensão para um comportamento de resgate eficaz de acordo com esse modelo, avaliado uma semana após o treinamento recebido; e identificar outras variáveis psicológicas que estão ligadas a essa propensão. Para este estudo foi adotada uma abordagem explicativa, que envolveu a implementação de um desenho experi-mental fatorial 2x2, com os fatores tomada de decisão e breve treinamento presencial sobre o PAP-4C, em uma amostra de 175 estudantes universitários de uma academia militar sem treinamento prévio em resgate em situações de desastre. Os resultados de uma ancova mostraram que a tomada de decisão baseada na emoção, prejudica a propensão para um comportamento eficaz no PAP-4C em comparação com a tomada de decisão baseada na racionalidade, após controlar estatisticamente as covariáveis. Em relação à identificação destas, uma série de características psicológicas mostraramse associadas à propensão para comportamentos de resgate eficazes. Nesse sentido, foram encontradas correlações positivas com tenacidade, honestidade, abertura, jo-vialidade, simpatia, atração emocional pelos outros e tomada de perspectiva do outro. Além disso, foram en-contradas associações positivas com estratégias de enfrentamento cognitivas destinadas a mudar a situação e estratégias de enfrentamento comportamentais cog-nitivas e motoras para reduzir a emoção. Finalmente, também foram encontradas associações negativas com aversão afetiva em relação aos outros e enfrentamento evitativo. Concluindo, por um lado, os resultados deste estudo pretendem mostrar a importância de os líderes dos grupos de resgate dizerem aos socorristas que, ao realizarem a tarefa de resgatar pessoas afetadas por de-sastres, devem evitar tomar decisões emocionais. Por outro lado, os resultados também oferecem orientação para a seleção de pessoal sem experiência anterior em assistência em situações de desastre, uma vez que foi identificada uma ampla série de variáveis psicológicas associadas à propensão para comportamentos eficazes no PAP-4C. Em resumo, esta investigação proporciona uma valiosa contribuição para o campo da assistência psicológica em situações de crise, ao identificar fato-res e variáveis psicológicas que podem influenciar os comportamentos de socorristas não profissionais e sem experiência prévia, ao resgatar e prestar apoio psicoló-gico a pessoas afetadas por um desastre

Analysis of the Internal and External Morphology of the Mandibular First Molar in a Chilean Sub-Population Using Cone-Beam Computed Tomography / Análisis de la Morfología Interna y Externa del Primer Molar Mandibular en una Subpoblación Chilena Mediante Tomografía Computarizada de Haz Cónico

SUMMARY: The mandibular first molar (MFM) commonly presents two roots with two canals in the mesial root and one or two canals in the distal root. However, morphological variations have been described in different populations, which must be considered when planning endodontic treatment. The aim of this study was to analyze the internal and external morphology of the MFM in a Chilean sub-population using cone-beam computed tomography (CBCT) images. An in vivo cross-sectional, descriptive, and observational study was conducted using CBCT exams from 351 right and left MFM. The data were analyzed by descriptive statistics using the Chi- Square test for categorical variables, Fisher's exact test, the Mann-Whitney U non-parametric test for two independent samples, and the Wilcoxon non-parametric test for related samples. Of the total sample, 1 root was observed in 2.27 % of the cases, 2 roots in 93.73 %, and 3 roots in 4 %. In relation to the number of canals, 71.23 % of the MFM showed 3 root canals, 16.81 % 4 canals, 9.69 % 2 canals, and 2.28 % 1 canal. Of all the studied cases, 2.3 % had a C-shaped anatomy. In terms of morphology, using Zhang's classification, variant 3 was observed in 71.23 %, variant 4 in 12.82 %, variant 1 in 9.67 %, variant 6 in 4 %, and variant 8 in 2.28 %. In conclusion, the morphology of the MFM is variable in a Chilean sub-population, and these variations must be considered before and during endodontic therapy. CBCT proved to be an effective tool for the in vivo study of tooth morphology.

El primer molar mandibular (MFM) comúnmente presenta dos raíces con dos canales en la raíz mesial y uno o dos canales en la raíz distal. Sin embargo, se han descrito variaciones morfológicas en distintas poblaciones, las que se deben tener en consideración al momento de planificar el tratamiento endodóntico. El objetivo de este estudio fue analizar la morfología interna y externa del MFM en una sub población chilena mediante el uso de imágenes de tomografía computarizada Cone Beam (CBCT). Se realizó un estudio transversal, descriptivo y observacional in vivo empleando exámenes CBCT de 351 MFM tanto derechos como izquierdos. Los datos se analizaron mediante estadística descriptiva empleando la prueba Chi-Cuadrado para variables categóricas, el test exacto de Fisher, la prueba no paramétrica de U-Mann-Whitney para dos muestras independientes y la prueba no paramétrica de Wilcoxon para muestras relacionadas. Del total de la muestra se observó 1 raíz en un 2.27 % de los casos, 2 raíces en 93.73 % y 3 raíces en un 4 %. En relación al número de canales un 71.23 % de los MFM mostraron 3 canales radiculares, un 16.81 % 4 canales, un 9.69 % 2 canales y un 2.28 % 1 canal. Del total de los casos estudiados un 2.3 % se presentó anatomía en forma de C. En relación a la morfología, empleando la clasificación de Zhang, se observó en un 71.23 % la variante tipo 3, en un 12.82 % la variante tipo 4, en un 9.67 % la variante tipo 1, en un 4 % variante tipo 6 y en un 2,28 % variante tipo 8. En conclusión, la morfología del MFM es variable en una subpoblación chilena y estas variaciones deben ser consideradas antes y durante la terapia endodóntica. El CBCT demostró ser una herramienta eficaz para el estudio in vivo de la morfología dentaria.