DEFINITIONS AND EPIDEMIOLOGY
Dental caries lesions, also known as dental cavities or tooth decay, are localized areas of demineralization of teeth, caused by acids resulting from bacterial metabolism of sugars and other carbohydrates. The disease of dental caries is typically caused by bacteria. Dental caries are among the most common chronic diseases in children worldwide and disproportionately affects underserved populations.1 Untreated cavities result in pain, loss of tooth structure, and infection of periodontal tissues, with lasting effects on function, growth, development, and quality of life.
The prevalence of dental caries has decreased in most developing countries over the past few decades. Although this decrease is multifactorial, increased exposure to fluoride is one of the most important factors influencing this decline.2 Dental caries remains prevalent, however, with substantial persistence in disparities. For example, the incidence of caries more than doubles from 23% in children aged 2–5 years to 56% in children aged 6–8 years.3 In children aged 2–8 years, Hispanic (46%) and non-Hispanic black (44%) children are substantially more likely to experience dental caries in the primary dentition as compared with non-Hispanic white children (31%). Additionally, 14% of children aged 6–8 years develop caries in their permanent teeth, with that proportion doubling to 29% by ages 9–11 years. By the age of 18 years, most children will have had some level of caries experience, with continued increases with age throughout adulthood. Thus, significant continued efforts are continuously needed to reduce caries prevalence and incidence around the world and throughout the lifespan.
As soon as teeth erupt, they are covered by bacteria arranged in a complex structure called an oral biofilm. Oral biofilms consist of many of hundreds of different types of microorganisms, varying in composition in different areas of the mouth. Oral biofilms accumulate predominantly in the pit and fissures of teeth, near the gum line and in between teeth when spaces are tight. Demineralization and remineralization of teeth are normal processes that occur in the oral cavity on a daily basis as people expose oral biofilms to nutrients that can be metabolized.
As a result of the metabolism of carbohydrates, especially simple and free sugars, oral biofilms produce acids, which can lead to loss of minerals in the tooth structure (i.e., demineralization). Saliva will naturally help regain minerals lost in a tooth, a process called remineralization. Dental caries is a biofilm-mediated, chronic and dynamic disease process, driven by sugars, that results from an imbalance between the processes of demineralization and remineralization. If not stopped or altered, over time, it will lead to a net loss of minerals and the development of defects in the tooth structure called caries lesions.
The imbalance between demineralization and remineralization is caused by an ecological shift or dysbiosis in the biofilm over time, because ...