Transmission of Periodontal Disease Through Saliva

Transmission of Periodontal Disease Through Saliva

Transmission of Periodontal Disease

Periodontal disease is associated with the pathogens Actinobacillus. actinomycetemcomitans and Porphyromonas gingivalis. These pathogens are found in both juvenile and adult periodontitis. People who don't have periodontitis are rarely found to have A. actinomycetemcomitans and P.gingivalis. Research has demonstrated that these pathogens are transmitted among family member.

When Do the Pathogens Colonize the Oral Ecosystem?

actinomycetemcomitans and P.gingivalis are not found in the mouths of infants and very young children. A Finnish study did not find the pathogens in a group of 1 to 7-month-old infants or in a group of young children aged 2 to 3 years. A variety of other pathogens are frequently found in low numbers in the mouths of people who are periodontally healthy, even when they are young children. In fact, young children who do acquire A. actinomycetemcomitans may only harbor the bacterium for a short time.

A. actinomycetemcomitans. Research indicates that children tend to acquire A. actinomycetemcomitans about the time that their permanent teeth erupt, which is generally around 5 to 11 years of age. Moreover, once the bacterium has colonized in the oral ecosystem during these years in a child's life, it becomes established.

P.gingivalis. Colonization of P.gingivalis generally occurs after the onset of puberty -- even then, according to empirical research, the bacterium does not colonize unless periodontal disease is present.

Saliva is a Vehicle for the Transmission of Bacterium

Periodontal pathogens thrive in inflamed periodontal pockets of infected gums. The pathogens are also found on the tongue, the mucosal surfaces, and in the saliva. Research has shown that people with periodontal disease exhibit periodontal pathogens in the inflamed pockets of infected gums that are genetically identical to the periodontal pathogens found in the saliva. This is taken as evidence that periodontal pathogens are spread from the diseased periodontal gums to the saliva. Moreover, the presence of periodontal pathogens in the saliva correlates with the presence of periodontitis. Research has further shown that treatment for periodontitis does markedly decrease or eradicate periodontal bacteria in the saliva; however, some periodontal bacteria in the saliva are seen to return to pretreatment levels as soon as six months post-treatment. The treatment implications are that follow-up periodontal treatment should occur within six months of the first or prior treatments. This treatment regimen is believed to help keep the levels of periodontal pathogens low in the saliva.

Propensity to spread microbiota. Research has shown that periodontal pathogens are spread from person to person through the saliva, just as most other bacterium may be shared. The likelihood of mouth-to-mouth transmission of periodontal bacteria is influenced by the susceptibility of the recipient to microbial colonization and by the frequency of exposure to the infectious saliva of others. Moreover, researchers theorize that mouth-to-mouth transmission of periodontal bacteria is more likely to result in colonization in a child than in adulthood. Developing oral bacteria microbiota may be more receptive to new bacterial invaders than established microbiota, which may be more resistant to colonization by new and different bacteria.

Bacterial transmission mechanics. A variety of research methods have been used to verify the modes of transmission of oral bacteria. Researchers have utilized fingerprinting techniques that permit the identification of specific clones or individual strains of bacteria. Historically, serotyping and biotyping was used to compare periodontal strains of bacteria. Most recently, researchers have been able to apply discriminative molecular methods to differentiate strains of bacteria at the deoxyribonucleic acid or DNA level. All periodontal pathogens exhibit a wide degree of genetic diversity across infected people. The heterogeneous mix of bacterial strains requires considerable research in order to verify transmission of the pathogens because the bacterial isolates of bacterial species must be examined and identified. Notably, once a periodontal pathogen has colonized in the mouth, it does tend to be stable and can persist in the oral ecosystem for years. Moreover, the propensity of bacteria to be transmitted from person to person is highly variable across the normal oral flora, with some bacteria colonizing in the mouths of children as young as 2-years of age -- but less variable for periodontal pathogens.

Routes of Transmission of Periodontal Disease

The vertical route of transmission. It is generally believed that parents can readily transmit periodontal pathogens to their children. In fact, one study found that A. actinomycetemcomitans was found in children under three years of age 26 times more often when the mother tested positive for periodontal disease. Moreover, when comparing A. actinomycetemcomitans colonization of in children, researchers found that one out of three children tested positive for the pathogen when a parent or parents tested positive for the bacterium, whereas children in families with parents who tested negative for the bacterium did not show evidence of colonization by A. actinomycetemcomitans. Given that prepubertal children rarely harbor P.gingivalis, when prepubertal children do harbor the bacterium, it was invariably transmitted to them by their parents.