After three consecutive applications of a 35% H(2)O(2) bleaching agent, the diffusion of the gel components through enamel and dentine caused severe toxic effects to cultured pulp cells.
Chlorhexidine gluconate (CHX) is recommended for a number of clinical procedures and
it has been pointed out as a potential cavity cleanser to be applied before adhesive
restoration of dental cavities. Objective: As CHX may diffuse through the dentinal
tubules to reach a monolayer of odontoblasts that underlies the dentin substrate,
this study evaluated the cytotoxic effects of different concentrations of CHX on
cultured odontoblast-like cells (MDPC23). Material and Methods: Cells were cultured
and exposed to CHX solutions at concentrations of 0.06%, 0.12%, 0.2%, 1% and 2%. Pure
culture medium (α-MEM) and 3% hydrogen peroxide were used as negative and
positive control, respectively. After exposing the cultured cells to the controls and
CHX solutions for 60 s, 2 h or 60 s with a 24h recovery period, cell metabolism (MTT
assay) and total protein concentration were evaluated. Cell morphology was assessed
under scanning electron microscopy. CHX had a dose-dependent toxic effect on the
MDPC-23 cells. Results: Statistically significant difference was observed when the
cells were exposed to CHX in all periods (p<0.05). Significant difference was also
determined for all CHX concentrations (p<0.05). The 60-s exposure time was the
least cytotoxic (p<0.05), while exposure to CHX for 60 s with a 24-h recovery
period was the most toxic to the cells (p<0.05). Conclusion: Regardless of the
exposure time, all CHX concentrations had a high direct cytotoxic effect to cultured
MDPC-23 cells.
OBJETIVO: este estudo teve como objetivo avaliar por meio de análise cefalométrica as diferenças nas proporções faciais de crianças respiradoras bucais e nasais. FORMA DE ESTUDO: coorte transversal. MATERIAL E MÉTODO: Foram selecionadas 60 crianças entre 6 e 10 anos que, após avaliação otorrinolaringológica para o diagnóstico do tipo de respiração, foram divididas em dois grupos: grupo I, constituído de crianças respiradoras bucais, com elevado grau de obstrução das vias aéreas e grupo II, composto de crianças respiradoras nasais. Os pacientes foram submetidos à avaliação ortodôntica por meio de radiografias cefalométricas em norma lateral, a fim de avaliar as proporções faciais, através das seguintes medidas cefalométricas: SN.GoGn, ArGo.GoMe, N-Me, N-ENA, ENA-Me, S-Go, S-Ar, Ar-Go; e os seguintes índices: iAF=S-Go / N-Me, iAFA=ENA-Me / N-Me e iPFA=N-ENA / ENA-Me. RESULTADO: Foi constatada que a inclinação do plano mandibular (SN.GoGn) nos pacientes respiradores bucais foi estatisticamente maior que nos respiradores nasais, enquanto que a proporção da altura facial posterior e anterior (iAF), e da altura facial anterior superior e inferior (iPFA) foram estatisticamente menores nos pacientes bucais, indicando altura facial posterior menor que a anterior e altura facial anterior inferior aumentada nesses pacientes. CONCLUSÃO: Pode-se concluir, então, que os respiradores bucais tendem a apresentar maior inclinação mandibular e padrão de crescimento vertical, evidenciando a influência da função respiratória no desenvolvimento craniofacial.
We concluded that mouth breathing children tend to have higher mandibular inclination and more vertical growth. These findings support the influence of the breathing mode in craniofacial development.
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