1. Stannous fluoride protects against erosion
Two separate investigations assessed the ability of two fluoride dentifrices to protect against the initiation and progression of dental erosion; a predictive in vitro erosion cycling model and a human in situ erosion prevention clinical trial. A stabilised stannous fluoride (SnF2) dentifrice (0.454 % SnF2 + 0.077 % sodium fluoride [NaF]; total F = 1,450 ppm F) [dentifrice A] and a sodium monofluorophosphate [SMFP]/arginine dentifrice (1.1 % SMFP + 1.5 % arginine; total F = 1,450 ppm F) [dentifrice B] were tested in a 5-day in vitro erosion cycling model and a 10-day randomised, controlled, double-blind, four-period crossover in situ clinical trial. In each study, human enamel specimens were exposed to repetitive treatments followed by erosive acid challenges. Both studies demonstrated statistically significant differences between the two dentifrices, A providing significantly better enamel protection. In vitro, dentifrice A provided a 75.8 % benefit over dentifrice B, while in the in situ model, A provided 93.9 % greater protection. This support the superiority of stabilised SnF2 dentifrices for protecting human teeth against the initiation and progression of dental erosion.

West NX et al. Erosion protection benefits of stabilized SnF2 dentifrice versus an arginine–sodium monofluorophosphate dentifrice: results from in vitro and in situ clinical studies. Clin Oral Investig 2017 21: 533-540.

Q For these investigations into protecting human teeth against the initiation and progression of dental erosion, which of the following is true of the findings?
A Only the in situ trial found stabilised SnF2 dentifrices to be superior
B Only the in vitro model found the SMFP]/arginine dentifrice to be better
C Both investigations support the superiority of stabilised SnF2 dentifrices
D Neither dentifrice had the desired protective effect

  1. The unvarnished truth
A randomised controlled trial of 275, two- to three-year-old children with carious lesions that had not developed cavities from 28 nonfluoridated rural preschools assessed the effectiveness of six-monthly fluoride varnish applications to prevent early childhood caries. Oral health education was given to children, parents and educators. A new toothbrush and toothpaste for each child was delivered to the parents at baseline and at four follow-up visits. The participants were randomly allocated to receive fluoride varnish or placebo applications every six months with 131 participants in the intervention group and 144 participants in the placebo group (no fluoride); of these children, 89 (67.9%) 100 (69.4%) completed the protocol respectively. Trained, calibrated dentists unaware of which group the children were in, performed visual exams at 6, 12, 18 and 24 months. Caries incidence was 45.0% for the experimental group and 55.6% for the control group with a mean dmft of 1.6 and 2.1 respectively. No adverse effects were reported. The authors concluded that six-monthly fluoride varnish application was not effective in preschool children from rural nonfluoridated communities at a high risk of caries.

Munoz-Millan P et al. Effectiveness of fluoride varnish in preventing early childhood caries in rural areas without access to fluoridated drinking water: A randomized control trial.
Community Dent Oral Epidemiol 2017 Aug 29.

Q Did six-monthly application of fluoride varnish?
A Reduce the likelihood of early childhood caries by 50%
B Show no beneficial effect in this population
C Stop because it was too expensive
D Increase caries due to the type of varnish used

  1. What price varnish?
Overall, evidence finds fluoride varnish effective to prevent caries but this is mostly based on high-risk populations, so this research aimed to assess its cost-effectiveness in a clinic setting in populations with different caries risk. The effectiveness was derived from an update of the most recent systematic Cochrane scientific review and applied to three different risk groups. Varnish was assumed to be applied twice yearly between age 6 and 18 years. Costs were deduced from fee charts. In low-risk groups, fluoride varnish was nearly twice as costly and minimally more effective (293 Euro, 8.1 DMFT) than no varnish (163 Euro, 8.5 DMFT). The incremental cost-effectiveness ratio (ICER) was 343 Euro spent per avoided DMFT. Application of fluoride varnish in the clinic setting is unlikely to be cost-effective in low-risk populations. There is the need to either target high-risk groups or to provide fluoride varnish at lower costs, possibly in nonclinic settings.

Schwendicke F et al. Cost-effectiveness of caries-preventive fluoride varnish applications in clinic settings among patients of low, moderate and high risk. Community Dent Oral Epidemiol 2017 Jul 06.

Q Fluoride varnish:
A Is cost-effective if given twice a month to low income children
B May be cost-effective to high-risk groups
C Is available only when paid for in Euros
D All of the above

  1. A chewing habit rewarded
The caries preventive effect of 1 year use of low-dosage xylitol chewing gum in a high-caries-risk adult population was evaluated by assigning 179 high-caries-risk adults to two experimental groups, xylitol and polyols (another type of sweetener). Caries status, salivary mutans streptococci (MS), and plaque pH were re-evaluated after 2 years from baseline in 66 xylitol and 64 polyol subjects and the net caries increment for initial, moderate, and extensive caries lesions and for the caries experience were calculated. For the xylitol group it was 1.25 +/- 1.26 and for the polyol group 1.80 +/- 2.33. Subjects treated with xylitol chewing gums had a reduction of risk rate at tooth level of 23% with respect to those treated with polyols. The amount of acid produced was statistically significantly lower during the experimental period in the xylitol group as was a decrease of the concentration of salivary MS. Subjects using the low-dose xylitol chewing gum showed a significantly lower increment of initial and extensive caries lesions and overall a lower increment of caries experience.

Cocco F et al.  The caries preventive effect of 1-year use of low-dose xylitol chewing gum. A randomized placebo-controlled clinical trial in high-caries-risk adults. Clin Oral Investigations 2017 Mar 16.

Q Which of the following was caused by use of a xylitol chewing gum?
A An average rise in the acidity
B Caries risk rate rise
C A rise in salivary mutans streptococci
D A fall in extensive caries lesions