Intra-familial comparison of supragingival dental plaque microflora using the checkerboard DNA–DNA hybridisation technique

Salivary microflora and mode of delivery: a prospective case control study

Background

Previous cross-sectional studies have suggested that the mode of delivery can influence the composition of oral microflora. The aim of this prospective study was to compare the salivary colonization in vaginally delivered children with children delivered by Caesarian section (C-section) during their first 6 months of life.

Methods

The study group consisted of 149 consecutively enrolled infants, delivered either vaginally (n = 96) or by C-section (n = 53) that volunteered after consent of their parents. Saliva samples were collected within 2 days after birth and then after 1, 3, and 6 months. A saliva sample from the mothers was obtained 6 months after delivery. The parents were asked to complete a questionnaire on socioeconomic factors, lifestyle, and hygiene at baseline and throughout the study period. All samples were analyzed with 13 pre-determined bacterial probes using checkerboard DNA-DNA hybridization.

Results

The groups were balanced at baseline concerning all relevant background factors. Gram-positive streptococci (S. mitis, S. salivarius) displayed the highest counts in both groups but a greater diversity was observed in the vaginally delivered group. A. naeslundi, A. odontolytics, F. nucleatum and L. salivarius were only detected among the vaginally delivered infants. The prevalence of S. sanguinis, S. gordoni, R. denticariosa, and B. dentinum increased by age in both groups but the prevalence was significantly lower in the C-section group (p < 0.05). There was a link between the mothers and their offspring’s concerning the salivary microbial profile.

Conclusion

The microbial composition in saliva differs by the mode of delivery during the first six months of life.

Supragingival plaque microbial analysis in reflection to caries experience

Background

Dental caries develops as a result of the metabolism of carbohydrates by cariogenic bacteria present in a complex biofilm. The present study aimed to examine if bacteria in pooled supragingival plaque samples quantified using a “checkerboard DNA-DNA hybridization” based panel of caries-related bacteria, could reflect the caries experience in a manner similar to saliva samples analysed using a chair-side method in a previous investigation.

Methods

A total of 86 mothers and their children aged 4–6 years and 12–16 years old participated. Caries experience (DMFT/dmft; Decayed, Missing and Filled Teeth for permanent and primary teeth) was registered clinically and radiographically. Caries was recorded at the D₃ level (caries into dentine). The D/d component was divided into three categories. A pooled supragingival plaque sample per participant was obtained from posterior approximal sites. Analyses of 15 bacterial species were performed using the checkerboard DNA-DNA hybridisation technique.

Results

No significant relationships were found between the bacterial scores and DMFT/dmft nor D/d groups.

Conclusions

Unlike the saliva samples and the chair-side method, interproximal pooled plaque samples analysed using the “checkerboard DNA-DNA hybridization technique” did not reveal any significant relations between the bacterial counts and the caries experience.