The effect of dentifrice quantity and toothbrushing behaviour on oral delivery and retention of fluoride in vivo

Abstract

While toothpaste FÀ concentration and rinsing regimen have well-characterised impacts on fluoride's effectiveness, other aspects of brushing regimen have much less well-established effects, in particular, dentifrice quantity and brushing duration. An in vivo study (n = 42) of oral fluoride delivery (i.e. oral disposition post-brushing), and retention (i.e. concentration of F À in saliva post-brushing, a known efficacy predictor), was performed to compare effects observed with those of dentifrice F À concentration and rinsing regimen. Subjects brushed with a NaF-silica dentifrice (Aquafresh Advanced, 1,150 ppm F À ) or a control dentifrice (250 ppm F À , same base), for 45, 60, 120 or 180 seconds with 0.5 or 1.5 g dentifrice, and rinsed with 15 ml water once or three times in a cross-over design. The F À concentration was measured in post-brushing expectorate, rinse and toothbrush washing samples, and in saliva between 5-120 minutes after brushing. Using 1.5 g versus 0.5 g dentifrice increased F À in all samples: oral retention of F À was almost doubled by this increase. Increasing duration of brushing had more complex effects. The amount of F À in the expectorate increased but decreased in both rinse and toothbrush washing samples. Oral F À retention increased, but only in the period 30-120 minutes after brushing. Over the ranges investigated, the order of importance on oral F À retention was: dentifrice F À concentration > quantity > rinsing regimen > brushing duration. Hence, increasing dentifrice quantity and, to a lesser extent, the duration of brushing, can elevate oral fluoride post-brushing. Evidence is accumulating that the importance of these variables to fluoride efficacy may have been underestimated.

Diet and the microbial aetiology of dental caries: new paradigms

“…Our results provide evidence in support of the importance of the duration of brushing reported for adults. Careful analysis of the fluoride values observed in this study shows that fluoride clearance is biphasic with an initial rapid loss of fluoride, followed by a much slower rate of loss for the ensuing 60 minutes, as previously reported by Duckworth and colleagues.…”

Whole-Saliva Fluoride Levels and Saturation Indices in 65+ Elderly during Use of Four Different Toothpaste Regimens

“…Previous studies typically measured the fluoride levels after a single or fewer tooth brushings [Duckworth and Morgan, 1991;Creeth et al, 2013;Nordström and Birkhed, 2013], but fluoride availability throughout 24 h of the day is most important for its ability to inhibit demineralization and enhance remineralization [ten Cate, 2013]. Peak values in saliva are certainly of interest, but decrease sharply immediately after application due to oral clearance and an exact cut-off level for beneficial effects is not established.…”

Período de wash-out en diseños experimentales cruzados con dentífrico de alta concentración de fluoruro

“…Estos residuos de F o depósitos podrían estar siendo liberados aun 12 h después del cepillado. Variaciones en el comportamiento de los voluntarios, como la duración del cepillado y el enjuague después del cepillado, han mostrado efecto en la concentración de F salivar cuando se ha analizado el clearance salivar 17 . En el estudio citado fue evaluada la concentración de F salivar inmediatamente al finalizar el cepillado y hasta 2 h después, mostrando que un uso de mayor concentración, mayor cantidad de pasta, mayor tiempo de cepillado y enjuague con menor volumen de agua favorecen la retención de F en la saliva.…”