Beyond the Tooth: How Endodontic Treatment May Improve Systemic Metabolic Health
Compiled by Elisabeth Lisican
For decades, the connection between oral health and systemic disease has focused largely on periodontal inflammation — leaving other common dental infections overlooked. In a landmark two-year longitudinal metabolomic study published in the Journal of Translational Medicine, Dr. Sadia Niazi and her team turn the spotlight on apical periodontitis, one of the world’s most prevalent oral diseases, and its potential role in metabolic dysfunction. Using advanced serum metabolomics, the research suggests that successful endodontic treatment may do more than save teeth — it may help rebalance systemic inflammation, glucose regulation, and lipid metabolism. In this Q&A, Dr. Niazi discusses the motivation behind the study, its key findings, and why this emerging evidence — detailed in the study “Longitudinal metabolomic analysis reveals systemic metabolic improvements following endodontic treatment” (read the study here) — could reshape how dentistry and medicine view root canal therapy as part of health care.
Context & Motivation
Lisican: What initially motivated your team to investigate whether root-canal / endodontic treatment might have systemic metabolic effects — beyond just resolving the local dental infection?
Dr. Niazi: What inspired my research was this gap that I observed, while the link between periodontal disease and systemic conditions such as diabetes and cardiovascular disease is globally recognized, the systemic impact of apical periodontitis had received surprisingly little attention and remained largely unexplored. Yet biologically, apical periodontitis and periodontal disease share similar inflammatory and microbial pathways that could plausibly influence systemic health.
What made this even more compelling was the high global prevalence of AP – it is the third most common oral disease, affecting nearly 50% of the global population. but its systemic impact and its recognition as a non-communicable disease remain largely ignored This raised an essential question: if AP is this widespread, could it also be contributing to systemic metabolic burden?
My earlier longitudinal study provided the first clue. We observed that after successful endodontic treatment, patients not only showed reduced systemic inflammatory markers but also improvements in key metabolic syndrome indicators such as HbA1C and lipid profiles. This suggested that treating the infection locally might exert broader metabolic benefits.
To understand why, I advanced the research using a multi omics longitudinal approach. By analyzing patients’ metabolomic profiles alongside serum biomarkers and clinical metabolic data over time, we sought to uncover the mechanistic pathways linking AP to systemic metabolic dysfunction, and to healing after endodontic treatment.
In short, my motivation stemmed from a major knowledge gap, the high global burden of AP, and early evidence from my own work showing that endodontic treatment may influence far more than the tooth – it may help rebalance systemic inflammation and metabolism.
Lisican: In your view, why has the connection between chronic dental infections (like apical periodontitis) and metabolic health been under-studied until now?
Dr. Niazi: The connection between chronic dental infections – such as apical periodontitis – and metabolic health has been under studied largely because medicine and dentistry have historically operated as two separate disciplines. This division has unintentionally reinforced the idea that the oral cavity is somehow disconnected from the rest of the body, when in reality it is the primary gateway to the entire body. By treating oral health in isolation, we overlooked the possibility that infections in the mouth could influence systemic inflammation and metabolic health.
Another reason is that global health research has traditionally focused on the “major” non communicable diseases – diabetes, cardiovascular disease, and obesity – without considering that chronic oral infections are also non communicable diseases that may act as persistent inflammatory drivers that worsen these conditions. Because the mouth is physically distant from many affected organs, its role as a potential source of systemic inflammation was simply not linked.
That mindset is now shifting. We now recognize that oral infections can disseminate pathogens and inflammatory mediators throughout the body, influencing metabolic pathways and contributing to disease vulnerability. The connection between oral and systemic health has become a central theme in modern global health discussions. Importantly, the World Health Organization now explicitly acknowledges this relationship and has integrated it into Global Health Strategies and the Bangkok Declaration, amplifying the powerful message: “No Health Without Oral Health.”
This shift and publication of this current study is finally bringing apical periodontitis – into the spotlight as an important contributor to metabolic health. It is only now that we are beginning to appreciate that what happens in the mouth doesn’t stay in the mouth – and chronic dental infections deserve the same attention as other inflammatory drivers of metabolic disease.
2. Study Design & Methods
Lisican: Could you walk us through the design of your two-year longitudinal metabolomic study — e.g., how many patients, what were the follow-up intervals, what kinds of analyses were done?
Dr. Niazi: Our study, published in the Journal of Translational Medicine, is the first two year longitudinal investigation to track how endodontic treatment influences systemic metabolism. We followed 65 patients treated at Guy’s and St Thomas’ NHS Foundation Trust, collecting blood samples before treatment and at multiple follow up intervals over two years.
Using nuclear magnetic resonance spectroscopy, we monitored 45 metabolites longitudinally, giving us a detailed picture of changes in amino acids, glucose, lipid metabolism, and insight into the broader metabolic pathways. This multi layered, integrated approach – combining metabolomics, serum biomarkers, microbiome, and clinical metabolic indicators data – represents one of the most comprehensive investigations to date into how endodontic treatment of apical periodontitis can influence whole body health.
Lisican: What were the key inclusion and exclusion criteria for participants (e.g., no diabetes, no systemic inflammatory disease, etc.), and why were those criteria important?
Dr. Niazi: We applied very strict inclusion and exclusion criteria to ensure the results reflected the true impact of apical periodontitis – without interference from other health conditions. We recruited medically healthy patients with AP who were referred for endodontic treatment at Guy’s Dental hospital.
To avoid confounding effects, we excluded anyone with factors known to influence inflammation or metabolism. This included smokers, pregnant women, patients with periodontal pockets >4 mm, and anyone with chronic inflammatory or autoimmune diseases such as asthma, inflammatory bowel disease, rheumatoid arthritis, Crohn’s disease, liver disease, or cancer. We also excluded patients who had taken antibiotics in the previous 3 months, had undergone surgery within 6 months, or were on medications that affect bone or metabolic pathways.
These criteria were essential because we wanted to isolate one question:
How much does apical periodontitis alone influence systemic metabolism and inflammatory profiles?
By removing all obvious confounders, we ensured that any metabolic or inflammatory changes we observed could be confidently linked to the infection, and to its resolution after endodontic treatment.
Lisican: Why did you choose nuclear magnetic resonance (NMR) spectroscopy of serum samples as your analytic method? What advantages does that method offer?
Dr. Niazi: I chose NMR spectroscopy because it is one of the most powerful and precise tools available for analyzing the body’s metabolic fingerprint. Unlike conventional blood tests that measure only a handful of markers, NMR allows us to track dozens of metabolites and lipoprotein subclasses simultaneously, giving a far richer picture of how the body processes fats, glucose, and other key molecules. For our longitudinal two year study, NMR detected subtle biochemical shifts over time, allowing us to follow how systemic metabolism changes, as an apical periodontitis infection is treated and healed. So, using NMR, we generated one of the most detailed metabolic profiles ever produced in endodontic research and uncovered changes that can’t be explored using standard laboratory methods.
3. Main Findings
Lisican: Your study reports significant changes in 24 out of 44 measured serum metabolites after successful endodontic treatment. Could you highlight which metabolic changes you found most meaningful (e.g., decreases in glucose, pyruvate, branched-chain amino acids; changes in lipids; increase in tryptophan)?
Dr. Niazi: One of the most striking findings was the clear shift toward a healthier metabolic profile after successful endodontic treatment. We observed reductions in serum glucose, pyruvate, cholesterol, and fatty acids, providing robust evidence that treating an endodontically infected tooth can meaningfully improve both glucose and lipid metabolism.
We saw a significant reduction in branched chain amino acids- metabolites strongly linked to insulin resistance, diabetes risk, and abnormal lipid profiles. Their decline suggests an improvement in the body’s ability to regulate glucose and fats.
Equally important was a progressive rise in tryptophan, a metabolite known to have protective effects against cardiovascular disease. Together, these changes indicate a shift toward a more favorable cardiometabolic state.
Lisican: How quickly did some of these changes become detectable (e.g., at 3 months, 6 months, 1 year, 2 years)? Are there both short-term and long-term effects?
Dr. Niazi: Some changes appeared surprisingly quickly. Within just a few months, patients already showed healthier cholesterol and fatty acid levels, indicating early improvements in lipid metabolism.
Other benefits unfolded more gradually. Blood glucose levels continued to fall over the entire two year follow up period, suggesting sustained improvements in insulin sensitivity and long term metabolic risk. Inflammatory markers also dropped progressively, showing that systemic inflammation steadily decreased once the endodontic infection was resolved.
Lisican: Your team suggests that metabolites associated with the tricarboxylic acid (TCA) cycle may be key regulators of the metabolic improvements. What does that imply about the biological mechanisms underlying the link between oral health and systemic metabolism?
Dr. Niazi: The metabolites that changed most consistently were those connected to the tricarboxylic acid (TCA) cycle – the central energy producing pathway of the body. This is a critical insight. It suggests that chronic apical periodontitis doesn’t just create local inflammation; it disrupts fundamental energy metabolism pathways, raising blood sugar, elevating cholesterol, and driving systemic inflammation.
Our findings imply a clear biological mechanism: Microbes and their toxins from an infected tooth can enter the bloodstream, trigger inflammatory responses, and interfere with energy metabolism. Once the infection is eliminated through endodontic treatment, the TCA cycle appears to normalize, restoring metabolic balance.
This is a powerful message. It shows that oral health is a metabolic health issue. An infection at the tip of a tooth can influence glucose processing, lipid regulation, and inflammatory pathways throughout the body. Treating that infection may help reduce long term risks of conditions such as diabetes and cardiovascular disease.
4. Clinical & Public Health Implications
Lisican: Based on your findings, what would you say to patients or general medical practitioners who view root canal therapy as purely “dental / cosmetic”? Could endodontic treatment now be considered part of holistic metabolic health care?
Dr. Niazi: It’s time to go beyond teeth and adopt a holistic approach to health, I firmly believe. For too long, dentistry and medicine have operated in separate silos, even though the mouth is biologically the main entry point to the entire body. What we now see in our metabolomic data is that a diseased tooth can influence blood sugar, cholesterol, inflammation, and even core energy production pathways and that successful endodontic treatment reverses many of these harmful effects.
This means endodontic therapy has real potential to become part of holistic metabolic health care, especially for patients at higher risk of cardiometabolic disease.
I envision a future where dentists and physicians work side by side, sharing information and co managing patients with chronic inflammation or metabolic risk or other vulnerable patients. That includes creating referral pathways, pilot programs for high risk patients, and training/educating clinicians on the profound links between oral infection and systemic disease. This isn’t just an academic idea; it’s a call to action.
Message for Patients
People must understand that their mouth is the main gateway to your general health, so looking after their oral health – and getting disease treated early – is the best course of action.
Ignoring an infected tooth isn’t a small issue: it can influence your whole body health for years.
Root canal treatment isn’t just about relieving pain or saving teeth – it’s about protecting your overall health, particularly the risk of chronic conditions like heart disease and diabetes.” So don’t ignore dental infections.
Ultimately, there’s nothing better than saving your own teeth – and safeguarding your systemic health in the process. Remember the WHO message: “No Health Without Oral Health.”
Message for Medical Practitioners
Root canal therapy should be recognized as an evidence based tool for lowering systemic inflammation and improving metabolic markers. Incorporating oral health assessments into general medical practice could transform prevention strategies for diabetes, cardiovascular disease, and chronic inflammatory conditions.
The best approach for high-risk patients should be referred to dental teams at the earliest stage of their journey to establish an effective preventative regime, so that timely endodontic treatment can be carried out to optimize oral health, and reduced related systemic risks
Lisican: Might it be possible to use serum metabolite markers (e.g., tryptophan, certain amino acids) as prognostic biomarkers for systemic health improvements after dental treatment? Your study hints at that — could you elaborate.
Dr. Niazi: Our findings suggest that serum metabolite markers – such as tryptophan, specific amino acids, glucose and lipids – could potentially serve as prognostic indicators of systemic health improvement following dental treatment, but this idea is still in an exploratory phase. What our study demonstrates is that treating chronic oral disease doesn’t just resolve local inflammation; it is also accompanied by measurable shifts in circulating metabolites that are linked to immune regulation, oxidative stress, and metabolic homeostasis. The pattern we observed indicates real potential; however, these need to be validated in larger, longitudinal cohorts. So, our study hints that serum metabolites may eventually become part of a precision health toolkit that links oral health interventions to whole body outcomes. But further research is essential before these markers can be translated into routine clinical practice.
Lisican: For patients with pre-existing metabolic risk — for example, people with prediabetes or elevated cardiovascular risk — do you think treating undiagnosed apical periodontitis could become part of a preventive strategy?
Dr. Niazi: Absolutely – that is one of the central messages of our study. For people already at higher metabolic risk, such as those with prediabetes, obesity, hypertension, or elevated cardiovascular risk, treating apical periodontitis – either symptomatic or asymptomatic – should absolutely be considered part of a preventive health strategy.
For high risk patients, addressing AP isn’t just a dental intervention – it’s an opportunity to reduce systemic disease burden. It adds a completely new dimension to preventive medicine.
So, yes – treating AP should be part of metabolic prevention. That is exactly the message this study delivers.
It’s time to rethink oral infections as silent contributors to chronic disease. By identifying and treating AP early, we can potentially help patients stabilize their blood sugar, improve lipid metabolism, lower inflammation, and reduce long term cardiometabolic risk.
In other words, endodontic treatment has a place in holistic healthcare. Treating a hidden dental infection today may help protect against diabetes and heart disease tomorrow.
5. Next Steps
Lisican: Are you or others planning investigations into how long these metabolic benefits last post-treatment — or whether repeated dental health monitoring could maintain systemic health over time?
Dr. Niazi: Yes – absolutely, our study opens the door, and the next phase is to scale up, diversify the cohorts, include patients with metabolic comorbidities, and follow them longitudinally to determine whether sustained endodontic health can indeed preserve systemic metabolic health in the long term.
6. Broader Perspective & Messaging
Lisican: What do you hope dentists, general physicians, and the public take away from your work?
Dr. Niazi:
Patient Message
Root canal treatment isn’t just about relieving pain or saving teeth, it’s about protecting your overall health, particularly your risk of chronic conditions like heart disease and diabetes. Dental infections shouldn’t be ignored; harmful bacteria from an untreated tooth can enter the bloodstream and impact the rest of your body. Ultimately, there’s nothing better than saving your own teeth and safeguarding your systemic health in the process.
Remember the WHO message: “No Health Without Oral Health.”
Dentist Message
Dental professionals must recognize that apical periodontitis, whether symptomatic or asymptomatic, is far more than a localized oral infection. It carries chronic systemic consequences. Early diagnosis and timely endodontic treatment are critical, especially for high risk or medically complex patients.
Our findings reinforce the need to view endodontic care not as an isolated procedure, but as a meaningful component of systemic health management and inflammation reduction and importantly the dentists should work closely with patient physicians to devise a more holistic care for the patients.
Medical Professional Message
We must move toward integrated care, where dentists and general physicians collaborate to identify and manage patient risk. Root canal therapy should be recognized as an evidence based tool for lowering systemic inflammation and improving metabolic markers. Incorporating routine oral health assessments into general medical practice could transform prevention strategies for diabetes, cardiovascular disease, and chronic inflammatory conditions. The best approach for high risk patients is early referral to dental teams, allowing timely endodontic treatment to optimize oral health and reduce systemic risks.
Lisican: Do you believe this study could shift how oral health is prioritized in broader healthcare guidelines (e.g., integration between dentistry and general medicine)?
Dr. Niazi: Yes – absolutely. Our study demonstrates clearly that oral health has tangible systemic effects, and that treating dental disease can influence biological pathways far beyond the mouth. These findings reinforce the urgent need for closer integration between dentistry and general medicine, especially within preventive health frameworks. Oral health must be recognized as a core component of healthcare policy, screening strategies, and chronic disease management — including conditions such as diabetes, cardiovascular disease, and the care of immunocompromised patients, such as cancer patients.
Lisican: If you could send one clear message to patients who might be apprehensive about root canal treatment, what would it be?
Dr. Niazi: My message for anyone feeling anxious about root canal treatment is: a root canal doesn’t cause harm-it prevents it. It is a safe, routine procedure designed to eliminate infection, save your natural tooth, and protect your overall health. Much of the fear surrounding root canals comes from misinformation, especially on social media, so before acting on anything you read online, it’s important to pause and check a few basics.
• First, check credentials – make sure the person giving advice is a qualified professional.
• Then look for reliable sources: Are they referring to reputable scientific evidence, or simply sharing a personal story that may not apply broadly?
• And be extremely wary of sensationalism. If a post sounds extreme, frightening, or too good to be true, it usually is.
Above all, seek guidance from a qualified dentist, not unverified social media sources, when making decisions about dental treatment. Dental infections are not something to ignore – when left untreated, the bacteria and their toxins can spread into the bloodstream and contribute to serious systemic issues, including increased risks of diabetes and heart disease. A root canal isn’t just about saving a tooth; it’s about preventing wider health problems.
And finally, remember that regular check ups and timely treatment are essential. Good oral health is closely linked to good systemic health, and preventive dental care is one of the simplest ways to protect both.
So my message is this: trust evidence, trust qualified professionals, and don’t let misinformation stop you from receiving a treatment that is safe, effective, and genuinely important for your overall health.