Correlation between caries related bacteria in plaque and saliva in different age group children

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Zainab J. Ja’far
Yasameen A.A. Al-Bayati,
Ghada I. Taha


Background: Dental plaque contains bacteria that are both acidogenic and acidoduric. Different types of
streptococci were identified in saliva. Although many bacterial subspecies have been shown to be associated with
caries, streptococcus mutans is still believed to be the most important bacterium in the initiation of this disease while
lactobacillus is correlated with the active caries episode. This study was conducted in order to estimate the
correlation between caries related bacteria in plaque and saliva in different age group children.
Materials and methods: Fifty three children aged 3-10 years old were chosen for this study. Recording of dental caries
was carried out by the dmfs index for primary teeth and DMFS index for the permanent teeth according to the
criteria suggested by the WHO. One ml of unstimulated (resting) whole saliva was collected from the children using
spitting method then diluted and applied on the surface of agar media specific for streptococcus mutans and
lactobacilli growth. Dental plaque sample was taken from the buccal surface of the maxillary second primary molar
by a clean toothpick and store in Epindorf tube which contain 1 ml. normal saline then inoculated in the same
growth media that were used with the salivary samples. Colonies of the bacteria were counted with the aid of
dissection microscope (15 X) on the basis of their characteristic morphology.
Results: Strong positive significant correlation was found between dmfs and ds components of the primary teeth,
Positive results was found when correlating dmfs or ds with streptococcus mutans in dental plague while a negative
correlation was found with lactobacilli. Negative correlation was found when correlating dmfs with streptococcus
mutans in saliva while the relation is positive with lactobacilli. In dental plaque and in saliva there was a strong
positive highly significant correlation between the DMF and the DS. Correlation coefficient between DMFS with the
bacterial counts of the caries related microorganisms (streptococci and lactobacilli) in the dental plaque and in
saliva revealed weak, negative not significant correlations.
Conclusion: The relation is not significant between the caries related microorganisms with each other in different
media; either the dental plaque or saliva.

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Orthodontics, Pedodontics and Preventive Dentistry