Efeito de nanopartículas de trimetafosfato de sódio associadas a dentifrício com concentração reduzida de fluoreto sobre a desmineralização do esmalte bovino: estudos in vitro e in situ

• Ano de defesa: 2014
• Autor(a) principal: Souza, Maria Daniela Basso de [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Dentifrícios; Esmalte dentário; Fluoretos; Nanopartículas; Fosfatos; Desmineralização do dente; Dentifrices
• Link de acesso: http://hdl.handle.net/11449/123774; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/20-05-2015/000828986.pdf

The aim of this study was to evaluate the effect of low-fluoride dentifrices (250 ppm F) containing nano-sized sodium trimetaphosphate (TMPnano) on the demineralization of bovine enamel as well their action on the biofilm formed in situ. For study 1 (in vitro), blocks of bovine enamel (n=144) were randomly divided into 12 experimental groups of dentifrices (pH 7.0). Placebo (no F or TMP), 1,100 ppm F (conventional dentifrice), 250 ppm F (250), 250 ppm F plus micrometric TMP (250-TMP) or nano-sized TMP milled for 24h (250-TMPnano24) or 48h (250-TMPnano48). Micrometric and nano-sized TMP were added to the formulations at concentrations of 0.05%, 0.1% and 0.25%. Blocks were subjected to a pH-cycling regimen and treatments with dentifrice slurries during 7 days. To evaluate mineral loss, surface hardness (SH) and the percentage of surface hardness loss (%SH) were analyzed. Fluoride (F), calcium (Ca), phosphorus (P) and Ca/P molar ratio in enamel were also determined. Data were submitted to Kruskal-Wallis test, followed by StudentNewmanKeuls' test (p<0.05). All concentrations of TMPnano significantly reduced %SH (p˂0.05). In addition, the dentifrices 250-TMPnano24 and 250-TMPnano48 led to higher F, Ca, P and Ca/P content in enamel only at 0.05% (p˂0.05); but only the 250-0.05TMPnano48 did not show significantly statistical difference when compared with 1,100 in respect of Ca/P molar ratio in enamel (p˂0.05). For study 2 (in situ), nineteen subjects wore palatal appliances containing 4 blocks of bovine enamel, and were randomly assigned to brush their teeth with placebo (no F or TMP), 250 ppm F (250), 250 plus 0.05% nano-sized TMP milled for 48h (250-TMPnano) and 1,100 ppm F (1,100 - conventional dentifrice) dentifrices, under cariogenic challenge (30% sucrose solution, 2 times/day), during 7 days. Post-cariogenic...