Oral microflora in infants delivered vaginally and by caesarean section.

International Journal of Paediatric Dentistry 2011; 21: 401–406 Background.  Early in life, vaginally delivered infants exhibit a different composition of the gut flora compared with infants delivered by caesarean section (C-section); however, it is unclear whether this also applies to the oral cavity. Aim.  To investigate and compare the oral microbial profile between infants delivered vaginally and by C-section. Design.  This is a cross-sectional case–control study. Eighty-four infants delivered either vaginally (n = 42) or by C-section (n = 42) were randomly selected from the 2009 birth cohort at the County Hospital in Halmstad, Sweden. Medically compromised and premature children (<32 weeks) were excluded. The mean age was 8.25 months (range 6–10 months), and parents were asked to complete a questionnaire on socioeconomic factors, lifestyle, and hygiene habits. Saliva was collected and analysed using checkerboard DNA–DNA hybridization. Results.  A higher prevalence of salivary Streptococcus salivarius, Lactobacillus curvata, Lactobacillus salivarius, and Lactobacuillus casei was detected in infants delivered vaginally (P < 0.05). The caries-associated bacteria Streptococcus mutans and Streptococcus sobrinus were detected in 63% and 59% of all children, respectively. Conclusion.  A significantly higher prevalence of certain strains of health-related streptococci and lactobacilli was found in vaginally delivered infants compared with infants delivered by C-section. The possible long-term effects on oral health need to be further investigated.