The Case for Fluoride in Dentifrice

Dental caries is the most widespread chronic disease in the world.^32,33 Tooth decay is initiated by acid production generated from sugar breakdown/metabolism (often in hard-to-clean tooth pits and fissures and interproximal crevices), and progresses over time to ever greater levels of severity unless it is detected and treated in its early stages. Over the past few decades there has been progress in the fight again caries – especially in tandem with fluoride exposure. A stark decline in the mean number of decayed, missing, or filled permanent teeth (DMFT) in 12-year-old U.S. children from 1967-1992 shows a clear association between an increase in those drinking fluoridated water (Figure 4). Importantly, fluoride dentifrice as topical application became commonplace during this timeframe as well.

Figure 4. The Association between Fluoridated Drinking Water and Dental Caries.³⁴

Figure 4. The Association between Fluoridated Drinking Water and Dental Caries.³⁴

Percentage of population residing in areas with fluoridated community water systems and mean number of decayed, missing (because of caries), or filled permanent teeth (DMFT) among children aged 12 years - United States 1967-1992.

Despite this, an estimated 35% of the global population (2-4 billion people) has untreated tooth decay in permanent teeth, varying by region and socioeconomic status (Figure 5).^32,35 A systematic caries epidemiological review concluded that “dental caries is a lifelong disease,” and while prevalence has declined in some age cohorts, there has been an increase in elderly persons having more teeth, root caries, and an average second prevalence caries “peak” at age 70, thus keeping the burden of disease high.³⁴ Dental caries constitutes one of the two leading causes of tooth loss, and is a major negative determinant of quality of life when it results in pain, eating difficulties, and missed school/work.^33,35

Figure 5. Estimated Global Prevalence of Untreated Dental Caries in Permanent Teeth for 2017.³²

Figure 5. Estimated Global Prevalence of Untreated Dental Caries in Permanent Teeth for 2017.³²

The multifactorial etiology of caries involves the interplay between sugars from ingested food, the bacterial biofilm in dental plaque, and the integrity of the tooth surface.³⁶ The importance of pH from ingested food and beverages in the modern diet also plays a role in rate of loss of tooth mineralization. The first two causative factors are theoretically modifiable; e.g., dietary sugar consumption can be reduced to lower acid attacks to tooth enamel, and good oral hygiene via diligent daily toothbrushing helps control the biofilm microbiota. In reality, however, sugar intake can be challenging to modify, especially given the high availability and consumption of sugary foods and drinks.^35,37 Similarly challenging is achieving complete oral hygiene plaque removal, which research has shown is infrequently achieved.^38,39

The third caries causative factor – the integrity of the tooth surface – may arguably represent the easiest intervention in the prevention of dental caries with use of a fluoride dentifrice. The mineral fluoride (from the trace element fluorine) is found in abundance in the environment and in natural water sources. One of the greatest public health achievements of the 20^th century was the recognition of fluoride as a significant contributor to the strengthening of tooth enamel and reduction of caries risk, first systemically via water fluoridation programs, and then as a topical agent delivered most commonly through fluoridated toothpastes or professional topical application.⁴⁰