DNA methylation pattern of apoptosis-related genes in ameloblastoma.

OBJECTIVES: DNA methylation is an important mechanism of gene control expression, and it has been poorly addressed in odontogenic tumours. On this basis, we aimed to assess the methylation pattern of 22 apoptosis-related genes in solid ameloblastomas. MATERIALS AND METHODS: Ameloblastoma fresh samples (n = 10) and dental follicles (n = 8) were included in the study. The percentage fraction of methylated and unmethylated DNA promoter of 22 apoptosis-related genes was determined using enzymatic restriction digestion and quantitative real-time PCR (qPCR) array. The relative expressions of the genes that showed the most discrepant methylation profile between tumours and controls were analysed by reverse-transcription quantitative PCR (RT-qPCR). RESULTS: Lower methylation percentages of TNFRSF25 (47.2%) and BCL2L11 (33.2%) were observed in ameloblastomas compared with dental follicles (79.3% and 59.5%, respectively). The RT-qPCR analysis showed increased expression of BCL2L11 in ameloblastomas compared with dental follicles, in agreement with the methylation analysis results, while there was no difference between the expression levels of TNFRSF25 between both groups. CONCLUSIONS: On the basis of our results, the transcription of the apoptosis-related gene BCL2L11 is possibly regulated by promoter DNA methylation in ameloblastoma. The biological significance of this finding in ameloblastoma pathobiology remains to be clarified.

Biannual fluoride varnish applications and caries incidence in preschoolers: a 24-month follow-up randomized placebo-controlled clinical trial.

UNLABELLED: Sound evidence on the effectiveness of fluoride varnishes (FV) to reduce caries incidence in preschool children is lacking. OBJECTIVE: To assess whether the application of FV in preschool children at 6-month intervals decreases the incidence of caries and produces any adverse effects. METHODS: A randomized, examiner- and patient-blind, placebo-controlled, parallel-group design, clinical trial, comprising 1- to 4-year-old children, 100 in each group (FV or placebo varnish, PV), was conducted in Rio de Janeiro, Brazil. Two trained pediatric dentists performed the clinical examinations (kappa = 0.85). Dental caries was recorded at the d2 (cavitated enamel) and d3 (dentine) levels using the International Caries Diagnosis and Assessment System. RESULTS: At baseline, the mean age of the participants was 2.4 years (SD 0.9) and the mean d3mfs was 0.8 (SD 1.9). Most of the children brushed their teeth with fluoride toothpaste and consumed fluoridated tap water. After 24 months, 89 and 92 children of the test and the control groups were analyzed, respectively. A total of 32 (35.9%) children in the FV group and 43 (46.7%) in the PV group presented new dentine caries lesions (χ(2) test; p = 0.14), showing relative and absolute risk reductions of 23% (95% CI: -9.5 to 45.9) and 11% (95% CI: -3.5 to 25.0). The mean caries increment differences between the test and control groups were -0.8 (95% CI: -2.0 to 0.4) at the d2 level and -0.7 (95% CI: -1.9 to 0.4) at the d3 level. Only 2 minor complaints regarding the intervention were reported. CONCLUSION: Although safe and well accepted, twice-yearly professional FV application, during 2 years, did not result in a significant decrease in caries incidence.

Bismuth recovery from acidic solutions using Cyphos IL-101 immobilized in a composite biopolymer matrix.

Impregnated resins prepared by the immobilization of an ionic liquid (IL, Cyphos IL-101, tetradecyl(trihexyl)phosphonium chloride) into a composite biopolymer matrix (made of gelatin and alginate) have been tested for recovery of Bi(III) from acidic solutions. The concentration of HCl slightly influenced Bi(III) sorption capacity. Bismuth(III) sorption capacity increased with IL content in the resin but non-linearly. Maximum sorption capacity reached 110-130mgBig(-1) in 1M HCl solutions. The mechanism involved in Bi recovery was probably an ion exchange mechanism, though it was not possible to establish the stoichiometric exchange ratio between BiCl(4)(-) and IL. Sorption kinetics were investigated through the evaluation of a series of parameters: metal concentration, sorbent dosage, type and size of sorbent particles and agitation speed. In order to reinforce the stability of the resin particles, the IL-encapsulated gels were dried; this may cause a reduction in the porosity of the resin particle and then diffusion limitations. The intraparticle diffusion coefficients were evaluated using the Crank's equation. Additionally, the pseudo-first-order and pseudo-second-order equations were systematically tested on sorption kinetics. Metal can be desorbed from loaded resins using either citric acid or KI/HCl solutions. The sorbent could be recycled for at least three sorption/desorption cycles.

Bruxismo y su asociación con la disfunción temporomandibular en niños. Revisión de literatura / Bruxism and its association with temporomandibular disorders in children. Literature review

Resumen Introducción: El bruxismo está definido como una actividad oral motora que consiste en el apretamiento o rechinamiento involuntario (rítmico o espasmódico no funcional) de los dientes, con una prevalencia de 5,9% a 49,6% en niños. Lo que podría contribuir a problemas clínicos asociados con la articulación temporomandibular. La asociación entre la disfunción temporomandibular (DTM) y el bruxismo en niños aún no está totalmente establecida. Objetivo: El objetivo de esta revisión de literatura es recopilar información actualizada de estudios que hayan abordado la asociación entre el bruxismo y la disfunción temporomandibular en niños de 3 a 12 años. Metodología: Se realizó una búsqueda en las bases de datos de Scopus, Pubmed y Scielo usando los descriptores "Niño", "Niños", "Preescolar", "Bruxismo", "Bruxismo del sueño", "Disfunción Temporomandibular"; y, "Síndrome de la Disfunción de Articulación Temporomandibular". Fueron incluidos artículos publicados en los últimos 15 años en idiomas español, inglés y portugués. Fueron incluidos estudios transversales, de cohorte, casos controles y ensayos clínicos aleatorizados. Resultados: Se evaluaron 242 artículos, de los cuales solo 11 fueron incluidos de acuerdo a los criterios de inclusión. Entre los estudios incluidos, dos de ellos no encontraron asociación entre DTM y bruxismo, tres encontraron una tendencia o probable asociación y seis encontraron una asociación positiva. Conclusiones: Existen estudios que relatan asociación entre el bruxismo y las disfunciones temporomandibulares en niños de 3 a 12 años, relacionando la presencia de signos y síntomas de la DTM con el bruxismo, pudiendo ser este último, un factor de riesgo para la presencia de DTM.

ABSTRACT Introduction: Bruxism is defined as an oral motor activity that consists of involuntary clenching or grinding (non-functional rhythmic or spasmodic) of the teeth, with a prevalence rate ranging from 5.9% to 49.6% in children, which could contribute to clinical problems associated with the temporomandibular joint. The association between bruxism in children and temporomandibular dysfunction (TMD) is not yet fully established. Objective: The objective of this literature review is to collect up-to-date information on studies that have addressed the association between bruxism and temporomandibular dysfunction in children ranging 3 - 12 years of age. Methods: A search was performed in the Scopus, PubMed and SciELO databases using the descriptors "Child", "Children", "Child, Preschool", "Bruxism", "Sleep Bruxism", "Temporomandibular Dysfunction" and "Temporomandibular Joint Dysfunction Syndrome." Articles published in the last 15 years in the Spanish, English and Portuguese languages were included. Results: A total of seventy-two articles were assessed. Only 11 articles were included according to the inclusion criteria. Among the included studies, two of them found no association between TMD and bruxism, three found a trend or probable association, and six found a positive association. Conclusion: There are studies that report an association between bruxism and temporomandibular dysfunctions in children ranging 3 - 12 years old, relating the presence of signs and symptoms of TMD with bruxism.