Cariogenic Biofilms and Caries from Birth to Old Age.

Caries is a complex microbial disease characterized by a multifactorial etiology. The disease is driven by cariogenic microbiota that metabolize dietary carbohydrates into acids, creating prolonged periods of low pH on the biofilm surrounding the teeth, which will result in loss of calcium from the teeth leading to carious lesions. Caries remains a major public health problem globally, ranking first for the decay of permanent teeth (2.3 billion people) and 12th for deciduous teeth (560 million children) according to the Global Burden of Disease study by the WHO in 2015. Different factors play a role in the development of the disease: (i) individual factors such as tooth morphology, saliva, and the oral microbiome, (ii) behavioral factors such as frequency and amount of fermentable carbohydrates in the host's diet and overall oral hygiene, and (iii) socioeconomic status and host genetics as well as modifying factors such as fluoride. Various models exist which explain the transition from a health-compatible oral microbiota to a cariogenic microbiota. Longitudinal studies may increase our knowledge of the oral microbial compositions in different age groups by analyzing the temporal sequence leading to carious lesions. Understanding the factors which control microbial colonization early in life as well as the keystone species that should be present or absent may provide us with strategies for the acquisition and maintenance of a health-promoting oral microbiome. Thus, the importance lies in understanding caries etiology to improve strategies for diagnosis, risk assessment, prevention, and (operative) treatment.