Episode 107: Saliva Testing & DNA Diagnostics in Dentistry

Why Dentists Are Interested in Your Saliva

[00:00:48 – 00:07:10]

Saliva does far more than keep the mouth moist. It neutralises acid, washes away bacteria, and delivers minerals that help repair early enamel damage. When its quantity or quality drops, the risk of cavities, erosion, gum disease, and infection rises significantly.

Saliva testing can measure how much saliva a patient produces — both stimulated (triggered by chewing) and resting — as well as its acidity and buffering capacity. Even the presence of specific bacteria, including those linked to heart disease and Alzheimer’s, can be identified through saliva samples.

Whilst these tests are not currently routine at OptiSmile, falling costs and advances in AI mean targeted saliva diagnostics may well become part of everyday dental care in the near future.

DNA Testing and Your Genetic Risk for Gum Disease

[00:07:26 – 00:09:12]

Not everyone responds to plaque in the same way. Some patients develop severe gum disease with relatively little bacterial build-up, and genetics can explain why. A gene variant known as IL-1 (interleukin-1) has been linked to an exaggerated inflammatory response to bacterial challenge.

Knowing a patient carries this marker allows a dentist to personalise their prevention plan — more frequent professional cleans, targeted antibacterial therapies, or a referral to a periodontist. As the episode puts it, genetics loads the gun, but behaviour pulls the trigger.

Ultimately, the fundamentals remain the same regardless of genetic risk: floss regularly, attend professional cleans, and address any lifestyle factors such as smoking or poorly controlled diabetes.

Identifying Bad Breath Bacteria Through Saliva

[00:09:19 – 00:10:58]

Saliva and plaque samples can be tested to identify the anaerobic bacteria responsible for bad breath — those found on the tongue or within gum pockets. Pinpointing these bacteria in theory allows for more targeted treatment rather than trial and error.

In practice, however, consistent oral hygiene habits — tongue scraping, flossing, ensuring gums do not bleed — address the root cause in most cases. Prescribed chlorhexidine products such as Curasept may also be recommended, with caution around over-the-counter alternatives that can stain teeth.

The IL-1 Marker and Implant Risk

[00:11:08 – 00:12:00]

The same IL-1 genetic marker that signals heightened gum disease risk also has implications for dental implants. Patients who carry this variant may be more prone to inflammation and bone loss around an implant over time.

For patients with a history of gum problems, a referral to a periodontist — who may carry out genetic testing and tailor a closer monitoring schedule — can help safeguard long-term implant success.

Buffering Capacity: How Well Does Your Saliva Handle Acid?

[00:12:08 – 00:13:48]

Buffering capacity refers to how effectively saliva can neutralise acids in the mouth. A low buffering capacity means the saliva struggles to counteract dietary acid, gastric reflux, or acidic drinks, leaving teeth more vulnerable to erosion and decay.

Testing buffering capacity is straightforward — samples of both resting and stimulated saliva are collected and analysed. For younger patients in particular, early testing could motivate positive changes: drinking more water, chewing sugar-free gum, and improving diet before damage accumulates.

Using Saliva to Guide Antibiotic Selection

[00:13:57 – 00:14:36]

In specialist periodontal care, samples taken from within gum pockets — known as crevicular fluid — can be cultured and tested to identify which bacteria are driving an infection. This allows the clinician to select the most appropriate antibiotic rather than relying on a broad-spectrum approach.

Whilst not a routine procedure, this type of targeted testing is particularly valuable in complex or persistent cases where standard treatment has not resolved the problem.

Cost, Accessibility, and the Road Ahead

[00:14:47 – 00:16:43]

Saliva and DNA testing remains relatively expensive for most patients, particularly when paying out of pocket. However, selective use — for instance, IL-1 testing in a patient with unexplained aggressive gum disease, or bacterial culture in a stubborn infection — can offer genuine value when the insight changes treatment decisions.

The trajectory is towards greater accessibility. Just as COVID rapid tests moved from clinics to chemist shelves, at-home saliva diagnostics capable of flagging gum bleeding, bad breath bacteria, or blood sugar levels may become a routine part of personal health monitoring within the next few years.

Personalised Dentistry and the Future of Diagnostics

[00:16:44 – 00:19:59]

Combining saliva flow data, buffering capacity results, bacterial profiles, and genetic markers builds a detailed picture of an individual patient’s risk — moving dentistry from a reactive, fix-it model towards genuine prevention. This kind of evidence can also be a powerful motivator, making it easier for patients to understand why more frequent check-ups or specific hygiene habits matter for them personally.

Research is already underway into saliva-based detection of systemic conditions including diabetes and certain cancers, with experimental tooth-mounted biosensors capable of streaming blood sugar readings via Bluetooth. Whilst not yet in clinical use, these developments signal how closely oral health and general health diagnostics are converging.

The collection process itself remains simple and non-invasive: chew a piece of wax, spit into a small cup, or swab the inside of the cheek for a DNA sample. No needles, no discomfort — just information that could shape smarter, earlier care.