Influence of salivary pellicle formation time on enamel demineralization – an in situ pilot study

Abstract

This study assessed the protective potential of salivary pellicles formed in situ over periods ranging from 2 to 24 h. Pellicles were produced on enamel slabs mounted on the palatal aspect of removable acrylic splints and exposed to the oral environment in three subjects for 2, 6, 12 and 24 h. Enamel specimens with and without pellicles were immersed in citric acid (1%) for 60 s, and the amount of dissolved calcium was measured by atomic absorption spectroscopy. In addition, specimens were processed for transmission electron microscopy (TEM). Mean values (standard deviations) for calcium release (mg/l related to the specimen's surface area of 5 x 5 mm(2)) were: 2-h pellicle 6.94 (1.55); 6-h pellicle 6.69 (2.05); 12-h pellicle 6.57 (2.31); 24-h pellicle 5.71 (2.46); enamel without pellicle 8.95 (1.66). There were no significant differences in calcium release that were dependent on pellicle formation time, but in comparison to enamel specimens without pellicle, significantly less (p <0.05) demineralization of the enamel was observed in pellicle-covered specimens. TEM showed that the pellicle was partly, but not completely dissolved following acid exposure. It is concluded that even a 2-h in-situ-formed pellicle layer protects the enamel surface to a certain extent against demineralization.

Methods for Assessment of Dental Erosion

“…Therefore, determination of dental enamel dissolution by assessing the amount of calcium or phosphate dissolved from the apatite crystals of dental hard tissue could also be regarded as a possible tool for assessing dental erosions. Hence, some authors had applied calcium determina-tion in erosive, acidic solutions after prolonged contact (range 2 min to 24 h) of the solutions with dental hard tissue using calcium sensitive electrodes, atomic adsorption spectrophotometer or the highly sensitive method of inductively coupled plasma mass spectrometry [68][69][70][71][72] Calcium-sensitive electrodes often need a specific pH of the environment to work precisely. Additionally, cal-cium complexes formed with certain acids (e.g.…”

“…Then a slice (50-200 tJm) is prepared perpendicular to the surface the same way as for tradi-tional TMR. Thereby, both depth of the erosive crater and the depth below the bottom of the crater at which mineral content was reduced (surface softening) can be assessed with TMR giving lesion depth and integrated Methods for Assessment of Dental Erosion 11 mineral loss as variables [89,90] [42] [67,68]. In these studies, TMR was used to record lesion depths from 20 tJm and more.…”

The cariogenic dental biofilm: good, bad or just something to control?

“…They also noted that short term exposure to phosphoric or citric acid could completely remove the protective pellicle. Later on, Hannig et al 11 (2003) demonstrated that a salivary pellicle only 3 minutes old conferred protection to enamel against citric acid attack. They demonstrated that the pellicle is 20-500 nm thick within the first two hours of exposure to saliva, depending on location, and is resistant to removal by a toothbrush (without toothpaste) and masticatory forces.…”

Determinação da mudança na composição da película adquirida formada sobre esmalte e dentina após exposição ácida: estudo proteômico

“…Uma vez que diferentes ácidos variam na sua capacidade de desmineralizarem o esmalte bovino , a proteção da película formada in situ na erosão do esmalte e da dentina causada pelos ácidos hidroclórico, cítrico e fosfórico foi analisada (WIEGAND et al, 2008 (HANNIG, M. et al, 2004;HANNIG, M. et al, 2003). A proteção média (30,5%) obtida para a dentina combinando os resultados dos 3 diferentes tipos de ácidos (WIEGAND et al, 2008) está de acordo com resultado de um estudo prévio , que encontrou uma redução da perda de cálcio da ordem de 27% após o tratamento com ácido hidroclórico (pH 2,3, 5 minutos).…”

“…Pode-se assumir que diferenças na estrutura do esmalte e da dentina poderiam afetar a composição da película adquirida (GLANTZ; BAIER; CHRISTERSSON, 1996) e, desta maneira, o seu potencial protetor, que é atribuído à sua habilidade em agir como uma barreira de difusão ou uma membrana semipermeável (HANNIG, M. et al, 2003). A maior porosidade e solubilidade da dentina comparada ao esmalte leva a uma desmineralização mais rápida, o que pode impedir que a película aja como uma barreira protetora (HARA et al, 2006).…”