Science Update Series: Saliva, Dental Caries and Periodontal Disease

written by CariFree

pattern recognitionIt was an interesting year in Dental Caries research. For this update series we started with about 100 articles, and pared it down to 50 that we believe broaden our knowledge and will help us better diagnose and treat our patients. Over the next several weeks we will walk through the research, feel free to ask questions or provide your experience in the comments section.


The series will be organized by unpacking what we refer to as the “Usual Suspects” or patterns we have identified as being the common reasons patients suffer from dental caries. Our ability to recognize and identify these patterns allow us to focus our diagnosis and treatment of the disease. The first we will tackle is saliva flow. Low saliva flow is the number one self-reported risk factor in our data base of nearly 13,000 patients. 63% of these patients self-report dry mouth or low saliva. When beginning the conversation with patients, starting with saliva is smart.


An interesting study that came out in December looked at saliva flow and its relationship to dental caries and periodontal disease:



This study examined the relationship between stimulated salivary flow rate and oral health status in an adult population. Multinomial multivariate logistic regression analysis was used to examine the associations of salivary flow rate with dental caries status and periodontal status at the individual level among 2,110 Japanese adults with ≥10 teeth. Then, a spline model was used to examine the nonlinear relationship between salivary flow rate and teeth with dental caries or periodontal disease in multilevel analysis. Odds ratios were calculated for a 1.0-mL/min reduction in salivary flow rate at a point.


After adjusting for confounding variables, participants with a flow rate ≤3.5 mL/min had significantly higher odds ratios for high caries status, and participants with a flow rate ≤1.4 mL/min had a higher odds ratio for broad periodontal disease, than did those with a flow rate >3.5 mL/min. In spline models, the odds ratio for teeth with dental caries or periodontal disease increased with reduced saliva secretion. The present findings suggest that decreased saliva secretion affects both dental caries and general periodontal health status. (Shimazaki Y, Fu B, Yonemoto K, Akifusa S, Shibata Y, et al. Stimulated salivary flow rate and oral health status. J Oral Sci. 2016 Dec 28. 2110 Japan Ad >10 teeth).


So, not only does decreased saliva flow impact risk for dental caries, but also risk for periodontal disease. How does this information impact how you assess your patients?



What do you think? Have you noticed dry mouth as a usual suspect in dental caries and/or perio in your patients?

3 Responses to “Science Update Series: Saliva, Dental Caries and Periodontal Disease”

  1. Michele

    Dry mouth associates itself with caries and perio.
    Less saliva inhibits thorough chewing of food, food trapping and lodging which inhibits tongue cleaning.
    Dry mouth is very uncomfortable as well often inhibiting thorough cleansing.

  2. Lance

    Yes, as a pediatric dentist I see it a lot especially with Asthmatic kids taking a variety of meds for that disease. Saliva? I wish they had it. Compound that with these asthma meds are high in sugar (sucrose). THen, these same kids have a dry mouth, take the meds at bedtime – a time when there is decrease saliva flow on regular people.

    I would like to throw this out to the gang here. Recent study got my attention. Kids who drink lots of soda have drier mouths. Here is the reason why: soda that has caffeine causes the drinker to urinate more thus losing fluids and these kids (who weigh much less than an adult) can get dehydrated easier. Thus, soda and caffeine leads to dehydration and thus less saliva. Add this to the amount of sugar in soda and you can see we have a ticking time bomb.

    Hope this helps.


  3. Kenneth

    Interesting finding, that reduced salivary flow affects periodontal health. Many times I’d do a perio check on a patient that had perio pockets. Hygienist was seeing them every three months. Often these patients had no cavities and very few restorations. Decay was not their problem.
    To me periodontal disease is a bit more of a mystery. Dental decay today, I believe, is preventable.
    I’m wondering if the link between salivary flow and periodontal health is linked to a drying of the tissues and that somehow leads to periodontal breakdown.
    As to why reduced salivary flow leads to more cavities, it really should not if you don’t have the acid forming bacteria in your mouth, such as s.Mutans. Maybe giving patients with dry mouth Xylitol in water would be very helpful.

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