Protective HLA alleles against severe COVID-19: HLA-A*68 as an ancestral protection allele in Tapachula-Chiapas, Mexico.

HLA is a polymorphic antigen presenter which has provided valuable information on the susceptibility of populations to viruses. Therefore, the study of HLA can reveal specific susceptibility or resistance alleles to severe COVID-19 in an ethnically dependent manner. This pilot study investigated HLA alleles associated with COVID-19 severity in Tapachula, Chiapas, Mexico. A total of 146 Mexican Mestizos were typed for HLA class I and II using PCR-SSP. The patients were classified according to the outcome (death or improvement) and the infection's severity (mild or severe). In addition, a group of exposed uninfected individuals was included. HLA-A*68 was found to be a protective allele against the severe infection and fatal outcome; pC = 0.03, OR = 0.4, 95% CI =0.20-0.86, and pC =0.009, OR = 0.3, 95% CI =0.13-0.71 respectively. HLA-DRB1*03 also appears to be a protective factor against fatal outcome pC = 0.009, OR = 0.1, 95%IC = 0.01-0.66; however, the low frequency of this allele in the studied population limits the statistical power. The severity and fatal outcome of COVID-19 patients in Tapachula, Chiapas depend more on the lack of resistance than susceptibility HLA alleles.

Influência do complexo flúor-xilitol no controle da placa dentária e do sangramento gengival em pacientes herbiátricos com aparelho ortodôntico fixo / Influence of fluorine-xylitol complex in the dental plaque and gingival bleeding control in herbiatric patients with fixed orthodontic brace

OBJETIVO: avaliar os efeitos de um dentifrício contendo flúor/xilitol na redução da adesão da placa à estrutura dentária, bem como no índice de sangramento gengival, em portadores de aparelho ortodôntico fixo. METODOLOGIA: foram avaliados 22 jovens, com idade entre 14 e 17 anos. Após a quantificação inicial dos índices, os jovens receberam instruções de escovação e começaram a utilizar somente os dentifrícios da pesquisa. Houve uma divisão aleatória da amostra em dois grupos (A e B). Na primeira semana todos utilizaram um dentifrício padrão e a partir da segunda semana os jovens do grupo A receberam um dentifrício contendo flúor, enquanto os do grupo B receberam um dentifrício contendo o complexo flúor-xilitol, que utilizaram durante vinte e oito dias, quando foram novamente avaliados (T1). Para a segunda fase (T2) houve inversão dos dentifrícios. RESULTADOS: foram comparados os resultados intra-grupo e nos dois grupos houve redução estatisticamente significante entre as fases inicial e T1, inicial e T2 e entre T1 e T2. Já na comparação entre os grupos não houve diferença estatisticamente significante entre eles, embora o dentifrício contendo flúor/xilitol tenha proporcionado uma porcentagem de redução do índice de sangramento gengival maior que o dentifrício contendo apenas o fluoreto de sódio, principalmente entre as fases inicial e T2, onde a redução no grupo A foi de 90,13 por cento e no grupo B foi de 78,84 por cento. CONCLUSÃO: a utilização de dentifrícios contendo flúor e xilitol, associada à instrução e motivação, parece ser um recurso bastante promissor para a manutenção da saúde bucal nos pacientes ortodônticos.

AIM: to evaluate the effects of a dentifrice containing fluorine/xylitol in the reduction of the adhesion of the plaque to the dental structure, as well as in the gingival bleeding index in patients who had orthodontic braces. METHODS: 22 teenagers, in between 14 and 17 years old were evaluated. After the initial quantification of the indexes, they received instructions of brushing and started to use only the dentifrices from the research. There was a random division of the sample into two groups, A and B. In the first week, they all used a standard dentifrice and since the second week the teenagers from group A received a dentifrice with fluorine, while the ones from group B received a dentifrice containing the fluorine-xylitol complex, using for 28 days, when they were evaluated again (T1). There was an inversion of dentifrices for second phase. RESULTS: the results were compared intra-groups and in both groups there was a statistically significant reduction between phases initial and T1, initial and T2 and between T1 and T2. However, comparing the groups, there was no statistically significant difference between them, though the dentifrice containing fluorine/ xylitol provided a percentage of reduction of gingival bleeding index bigger than the one containing only sodium fluoride, specially between phases initial and T2, where reduction in group A was 90.13 percent and in group B was 78.84 percent. CONCLUSION: the utilization of dentifrice containing fluorine and xylitol, associated to instruction and motivation, seems to be a promising resource for maintenance of oral health in orthodontic patients.

Utilization of xylitol as a preventive substance in dentistry

Dental caries is an infectious-contagious disease of multifactorial origin, which requires interference in one or more of its etiologic factors for prevention. Within this context, the utilization of xylitol is highlighted, which was initially studied as a sugar substitute because of its similarity as regards the sweetening power and later was also employed in other forms for caries prevention and control. The purpose of this study is to describe, by means of a review of the specialized literature, how xylitol can be used as an anticariogenic agent, demonstrating its properties and possible mechanisms of action in the prevention and control of dental caries. Analysis of many studies on xylitol revealed that it is available in many forms: chewing gums or tablets, mouthrinses, or even associated to toothpastes. Its anticariogenic properties are related to the reduction in plaque adhesion, remineralization of incipient carious lesions, and specific reduction of S. mutans.

A importancia do aleitamento natural na prevençao de alteraçöes miofuncionais e ortodônticas / The importance of the natural milk to prevent myofuncional and orthodontics alterations

Atualmente tem-se enfatizado a importância do aleitamento natural uma vez que o leite materno é o melhor alimento do ponto de vista nutricional, reforça o sistema imunológico do bebê e pode exercer um importante papel preventivo quanto a alteraçöes miofuncionais e ortodônticas. O presente estudo teve como objetivo observar o aspecto preventivo da amamentaçäo natural relacionada aos hábitos bucais deletérios e alteraçöes nas funçöes estomatognáticas e oclusäo dentária. Para tanto foram avaliadas l80 crianças, de ambos os gêneros, na faixa etária de quatro a seis anos de idade, matriculadas em pré-escolas de rede pública de Bauru-SP. Os resultados mostraram que a amamentaçäo natural previne a ocorrência de hábitos bucais deletérios, principalmente quanto à sucçäo de chupeta: diminui a incidência de alteraçöes quanto às funçöes estomatognáticas, mas näo há relaçäo com a oclusäo dentária. Quanto a este último aspecto, foi possível observar que quando alteraçöes na fonoarticulaçäo e deglutiçäo estäo presentes, ocorre um aumento de alteraçöes da oclusäo e vice-versa