Can Infants Develop Dental Plaque Without Teeth?
No, infants cannot develop true dental plaque biofilm on their gums before teeth erupt, because bacterial colonization by cariogenic organisms requires the presence of erupted tooth surfaces for attachment and biofilm formation. 1
Why Teeth Are Required for Plaque Formation
Dental plaque biofilm formation begins soon after a tooth surface is present, not before, as the bacteria require hard tooth surfaces to adhere to and form the complex biofilm structure. 1
The oral mucosa and tooth surfaces of children who are beyond infancy (meaning after teeth have erupted) are populated by pathogenic and nonpathogenic bacteria that form plaque. 1
Infants acquire cavity-causing bacteria primarily from their mothers, but colonization requires the presence of erupted teeth as a substrate for bacterial attachment. 2
The typical "window of infectivity" for acquisition of cariogenic microorganisms, including Streptococcus mutans, occurs between 19 and 31 months of age—well after primary teeth have begun erupting at 6-8 months. 1, 2, 3
What Happens Before Teeth Erupt
Before tooth eruption (typically starting at 6-8 months), the infant's oral cavity contains bacteria on mucosal surfaces, but these do not form the structured biofilm characteristic of dental plaque. 3
Once a tooth surface is cleaned or newly erupted, a conditioning film of proteins and glycoproteins (acquired enamel pellicle) is rapidly adsorbed to the tooth surface, and only then can bacterial colonization and plaque biofilm formation begin. 4
The oral microbiome exists in infants before teeth erupt, but the complex, structured dental plaque biofilm specifically requires tooth surfaces for the adhesion mechanisms and biofilm architecture to develop. 5, 6, 4
Clinical Implications
Oral health care should begin immediately with the eruption of the first tooth, including twice-daily brushing with fluoridated toothpaste, because this is when plaque formation becomes possible. 3
The first dental examination should be scheduled within 6 months of first tooth eruption but no later than 12 months of age. 2, 3
Newly erupted teeth are most vulnerable to caries because they provide the substrate for bacterial colonization and plaque formation, and early colonization by cariogenic bacteria occurs soon after eruption. 1, 3
Important Caveat
While true dental plaque cannot form without teeth, infants do have oral bacteria on their gums and mucosal surfaces. However, this is fundamentally different from dental plaque biofilm, which is a structured microbial community embedded in a matrix that specifically forms on tooth surfaces. 5, 6, 4