1. The Protective Effects of Toothpaste Against Erosion By Orange Juice: Studies in Situ and in Vitro

The Protective Effects of Toothpaste Against Erosion By Orange Juice: Studies in Situ and in Vitro

Reference: Hooper SM, Newcombe RG, Faller R, Eversole S, Addy M, West NX. J Dent. 2007 Jun;35(6):476-81. Epub 2007 Feb 27


The results of this study provide further support for tooth brushing before meals. Results further suggest the stannous fluoride dentifrice could be used to provide significant erosion protection in susceptible patients versus that provided by conventional fluoride products.


Consumption of soft drinks, fruit juices and sport drinks has increased dramatically in the UK, the US, and elsewhere. Previous studies have demonstrated the erosive nature of these acidic soft drinks. The objective of this study was to determine the protective effects of experimental stannous fluoride-based toothpaste, containing sodium hexametaphosphate, against an erosive challenge (orange juice) on tooth enamel.


  • This research included a 15-day challenge in vitro study and a 15-day in situ single blind, 3-way, crossover clinical trial.
  • The following formulations were tested:
    1. experimental stannous fluoride dentifrice with sodium hexametaphosphate for cosmetic benefits (P&G);
    2. a benchmark sodium fluoride dentifrice (Crest® Cavity Protection, P&G);
    3. negative control, water.

  • Flat, polished human enamel samples with a surface profile of +/-0.1μm, were exposed to the three regimens.
  • The orange juice used as erosion challenge had a pH 3.8.
  • 15 volunteers wore an intra-oral appliance with 2 specimens of enamel embedded in the mid-palatal region from 9:00 to 17:00 (removed for 1 hour at lunchtime). Whilst appliances were in place, no food or drink other than water and the designated orange juice were consumed. Volunteers were asked to rinse with a toothpaste slurry or water at 9:00 and 13:00 followed by consumption of 250 ml orange juice 1 and 3 h later.
  • Subjects were treated with one study formulation for 5 days followed by two nontreatment days.
  • A profilometer was used to measure depths of the resulting eroded areas at days 5, 10 and 15.


There was significantly more erosive damage on the specimens exposed to the benchmark toothpaste (NaF) and negative control (water) compared to the test stannous fluoride toothpaste in both the in situ (Figure 1) and in vitro (Figure 2) studies.

Figure 1. In Situ Loss of Material*

In Situ Loss of Material

Figure 2. In Vitro Loss of Material*

In Vitro Loss of Material

* mean value based on duplicate determinations of two enamel specimens

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