Salivary mucins, key components of mucus, actively protect the teeth from cavity-causing bacteria, new research shows.
Mucus is a sophisticated bioactive material with powerful abilities to manipulate microbial behaviour, the researchers noted.
"The research suggests that bolstering native defences might be a better way to fight dental caries than relying on exogenous materials, such as sealants and fluoride treatment," said first study author Erica Shapiro Frenkel from Harvard University.
The cavity-causing bacteria called Streptococcus mutans attach to teeth using sticky polymers that they produce, eventually forming a biofilm - a protected surface-associated bacterial community.
As S. mutans grows in the biofilm, it produces organic acids as metabolic byproducts that dissolve tooth enamel, which is the direct cause of cavities.
"We found that salivary mucins do not alter S. mutans' growth or lead to bacterial killing over 24 hours," Frenkel said.
Instead, they limit biofilm formation by keeping S. mutans suspended in the liquid medium.
"This is particularly significant for S. mutans because it only causes cavities when it is attached, or in a biofilm on the tooth's surface," she added.
Frenkel noted that the oral microbiome is better preserved when naturally occurring species are not killed.
"The ideal situation is to simply attenuate bacterial virulence," she pointed out.
"Defects in mucin production have been linked to common diseases such as asthma, cystic fibrosis, and ulcerative colitis," Frenkel added.
The study appeared online in the journal Applied and Environmental Microbiology.
