Towards understanding the establishment and maintenance of a healthy oral ecosystem

Oral health is usually approached and studied as an isolated part from the rest of the human body, while there is a growing consensus that oral health should be considered an integral part of overall health. Several longitudinal birth cohort studies have been initiated, aiming at understanding the biological processes involved in the etiology and course of non-communicable diseases from childhood onwards. However, in most cohort studies that examine both the gut and oral microbiome, oral health data collection is either omitted, conducted using methods that omit the identification of early-stage caries, or based on self-reported oral health factors that may confound microbiome analyses. This thesis aimed to improve our understanding of the establishment of and maintaining a healthy oral ecosystem in the first 1 000 days of life.