The oral microbiota of Irish children in health and disease: a longitudinal and cross sectional study
University College Cork
The oral cavity harbours a very rich and diverse microbial community. In the last decade, the oral microbiota of children and adults has been studied in detail using continuously developing DNA sequencing methods. In particular focusing on the oral microbiome changes in the presence of diseases such as dental caries, periodontal disease and the relationship of the oral microbiome with oral health and disease states. The overall aim of these studies was to unravel the complexity of the oral ecosystem and the driving forces behind the imbalance of this ecosystem which leads to increased risk of disease and poor oral health. The oral microbiota of the edentulous neonate and infant is poorly characterised particularly the dynamics of the oral microbial changes of the neonate as it grows from birth to an older age. This is important as it would give researchers that study the oral health of children a better understanding of the foundation of the oral microbiome. An important addition would also be to explore the influence feeding modality (breast or formula), introduction of solid foods, eruption of teeth, antibiotic intake, fluoridation intake and oral hygiene habits all have on the infant oral microbiota. Gaining a better understanding of the dynamics and maturation of the oral microbiome of neonates from birth is important to identify any microbial factors which increase the risk of dental diseases in these children. In this ORALMET study, we recorded the oral microbial changes from birth to 2 years of age of infants (n=382) (year 3 data is not included in this thesis) born via C-section or Vaginal delivery. Factors included in our analysis of the oral microbiota of these infants included breast feeding duration and the influence of the maternal microbiota (saliva/skin or vaginal microbiota). We observed that breast feeding duration does not have an effect on the oral microbiota of infants, and birth mode has an effect on the oral microbiota of infants up to 4 weeks of age only, but not beyond that. The oral microbiota changes in composition are most apparent from 6 months of age to 2 years of age, with less microbial changes within the oral cavity from birth to 8 weeks of age. The oral microbiota composition is continually changing and developing up to 1 year of age and at 2 years of age, illustrating continuous maturation, with no evidence of stability by 2 years of age. The second part of the ORALMET study (cross-sectional study) compared the oral microbiota of children between 3-5 years with SECC (n=68) and without caries (n=70). We observed distinct microbiota differences in the caries microbiota of children with active ECC, and the presence of species in the salivary microbiota of children with active caries, but not in the salivary microbiota of children without caries. ORALMET is the first in depth longitudinal study of the oral microbiome from birth of the infant, together with the influence of the maternal microbiota and also the first microbiota study of Irish children with and without caries. Together these studies provide us with information of the infant oral microbiome and a better understanding of the microbial dynamics within the oral cavity of neonates, infants and children.
Neonates , Oral microbiota , Birth mode , Dental caries , Children
Hurley, E. 2017. The oral microbiota of Irish children in health and disease: a longitudinal and cross sectional study. PhD Thesis, University College Cork.