How does the early life environment influence the oral microbiome and determine oral health outcomes in childhood?

Abstract

The first 1000 days of life, from conception to 2 years, are a critical window for the influence of environmental exposures on the assembly of the oral microbiome, which is the precursor to dental caries (decay), one of the most prevalent microbially induced disorders worldwide. While it is known that the human microbiome is susceptible to environmental exposures, there is limited understanding of the impact of prenatal and early childhood exposures on the oral microbiome trajectory and oral health. A barrier has been the lack of technology to directly measure the foetal "exposome", which includes nutritional and toxic exposures crossing the placenta. Another barrier has been the lack of statistical methods to account for the high dimensional data generated by-omic assays. Through identifying which early life exposures influence the oral microbiome and modify oral health, these findings can be translated into interventions to reduce dental decay prevalence.

Keywords: -omics; Oral microbiome; dental caries; environment; exposures; postnatal; prenatal.

Figure 1:

Key aspects and factors effecting the oral microbiome trajectory. Relative abundance plot derived from Dzidic et al.[18]

Figure 2.

A. At 14 – 19 weeks in utero, enamel and dentine begin to mineralize at the future dentine-enamel junction (DEJ) on the cusp tip. Subsequently, enamel and dentine deposition occurs in a rhythmic manner forming incremental lines—akin to growth rings in a tree—in both enamel and dentine [109]. At birth, an accentuated incremental line, the neonatal line, is formed due to disturbances in the secretory cells during matrix deposition [110]. After birth, teeth continue to manifest daily growth lines, which reflect chronological ages at various positions within the tooth. B. Due to a change in crystal orientation and density, the neonatal line is a clear histological landmark that demarcates pre- and postnatally formed parts of teeth. The neonatal line forms regardless of the type of delivery (C-section vs vaginal).