The endodontic challenge in patients with diabetes

Dr Samer N. Hanna

Tue. 27 January 2026

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Diabetes mellitus (DM) is a chronic metabolic disorder that has emerged as a major global health concern. It is broadly classified into two main types. Type 1 DM, typically manifesting at a young age, is an autoimmune condition characterised by insufficient insulin production resulting from immune-mediated destruction of pancreatic beta cells. In contrast, Type 2 DM, which generally develops during adolescence or adulthood, is defined by reduced sensitivity of peripheral tissue to insulin, leading to insulin resistance and impaired glucose metabolism.¹

The global prevalence of DM continues to rise at an alarming rate. As of 2022, it is estimated that more than 800 million adults worldwide have DM—more than quadruple the number recorded three decades ago.² Around 7% of adults were affected in 1990, whereas by 2022, the prevalence had reached approximately 14%.² This escalating trend poses serious public health challenges, and an estimated 1.6 million deaths in 2021 were directly attributed to DM and its complications.²

DM is associated with a wide range of systemic complications; however, its impact on oral health is particularly significant. Individuals with DM are known to exhibit a higher prevalence of periodontal disease, an increased susceptibility to dental caries, persistent halitosis and xerostomia. Moreover, they are more prone to oral fungal infections and frequently experience delayed wound healing, which can complicate both routine and surgical dental procedures.³

Effects of DM on pulpal and periapical tissue

Hyperglycaemia in DM induces widespread microvascular damage and impaired blood flow, affecting not only systemic tissue but also the dental pulp and periapical region. Histopathological studies have shown basement membrane thickening, reduced vascular density and perivascular collagen deposition within pulpal tissue of patients with DM—factors that collectively restrict oxygen and nutrient supply essential for normal repair processes. Moreover, chronic hyperglycaemia promotes the formation of advanced glycation end-products, which exacerbate oxidative stress, enhance fibrotic changes, and further impair immune response and tissue healing in the pulpal and periapical tissue.^4, 5

“DM is associated with a wide range of systemic complications; however, its impact on oral health is particularly significant.”

Immunological dysfunction in DM further compromises the host’s ability to combat infection and inflammation. Reduced neutrophil activity, altered cytokine expression and a state of chronic low-grade systemic inflammation collectively impair the resolution of infectious processes. As a result, dental pulp in patients with DM is more susceptible to persistent inflammation, chronic pulpitis and delayed healing after injury or microbial insult.⁵

In a study investigating the effects of Type 2 DM on clinically normal pulpal tissue, the authors observed morphological alterations resembling those seen in age-related pulpal changes.⁴ These included fibrosis, reduced vascularity and pulpal calcifications, accompanied by enhanced pro-inflammatory activity. Such pathological changes may impair the pulp’s defence mechanisms, diminish its response to irritants and infections, and compromise its healing capacity after injury or restorative procedures.⁴

Endodontic implications

Clinical evidence strongly suggests that DM—particularly when poorly controlled (i.e. haemoglobin A_1c [HbA_1c] ≥ 7%)—is associated with an increased prevalence of periapical periodontitis, impaired periapical healing and lower success rates after root canal treatment. In a prospective cohort study, patients were categorised into three groups: no DM, well-controlled DM (HbA_1c < 7%) and poorly controlled DM (HbA_1c ≥ 7%).⁶ After a one-year follow-up, the authors concluded that DM significantly delays the healing of periapical periodontitis and that the presence of periapical periodontitis itself may further exacerbate systemic inflammation in individuals with Type 2 DM. Interestingly, the study also highlighted a potential bidirectional relationship between endodontic therapy and glycaemic control, suggesting that successful root canal treatment contributes to improved metabolic regulation in patients with DM.⁶ Similarly, another study evaluating the healing of periapical periodontitis in patients with DM reported that DM may negatively influence periapical tissue repair and delay healing after non-surgical root canal treatment.⁷ The study further found that patients with DM were approximately five times more likely to experience persistent periapical periodontitis after root canal treatment compared with those who did not have DM.

Chronic hyperglycaemia has also been shown to alter the nanostructure and mineral composition of root canal dentine, resulting in reduced mechanical integrity and greater susceptibility to structural damage during endodontic instrumentation and obturation.⁸ These pathological alterations highlight the importance of meticulous treatment planning and technique adaptation when managing endodontic care in patients with DM.⁸

Clinical considerations and treatment modifications: Step-by-step guide

Diagnosis
Prior to treatment, it is essential to confirm the patient’s DM status using recent HbA_1c results, as values above 7% indicate poor glycaemic control and are associated with delayed or impaired healing. Collaboration with the patient’s physician or endocrinologist is recommended to evaluate systemic stability and determine the safety of proceeding with endodontic therapy. Clinicians should also recognise that patients with DM may exhibit atypical or diminished clinical symptoms due to neuropathic alterations and chronic low-grade inflammation, making comprehensive pulpal testing and advanced radiographic assessment—including CBCT imaging—critical for accurate diagnosis and periapical evaluation.^5, 9 Moreover, pulp testing may yield unreliable results in patients with DM, as responses are often delayed or blunted, particularly in cases of poor glycaemic control.¹⁰

“DM profoundly influences endodontic outcomes, primarily by impairing pulpal and periapical healing through microvascular compromise and immune dysregulation.”

Anaesthesia
Local anaesthetics containing vaso-constrictors should be used with caution in patients with DM, especially those with hypertension or coronary artery disease, owing to potential cardiovascular risks. Preoperative blood glucose measurement is recommended, and treatment should be postponed if the patient presents with hypoglycaemia or hyperglycaemia in order to minimise the risk of adverse events. Clinicians should also anticipate a delayed onset or reduced efficacy of anaesthesia in individuals with DM because microvascular changes may impair local anaesthetic diffusion and distribution within the tissue.^9, 11

Access, shaping and cleaning
Adherence to minimally invasive endodontic principles is essential when treating patients with DM. Conservative access cavity design should aim to preserve as much tooth structure as possible, particularly the pericervical dentine, which plays a critical role in maintaining fracture resistance. This consideration is especially important in individuals with DM, whose dentine often demonstrates reduced mineralisation and altered nanomechanical properties, increasing its susceptibility to fracture.

Minimally invasive instrumentation protocols using flexible rotary nickel–titanium systems are recommended in order to limit stress on the weakened dentine. For irrigation, sodium hypochlorite remains the gold standard for antimicrobial disinfection. However, rather than using high-power ultrasonic activation, which may induce microcracks in the more brittle dentine of patients with DM, clinicians should opt for gentle sonic agitation to enhance smear layer removal while preserving dentine integrity.^8, 12, 13

Obturation and definitive restoration
The use of bioceramic sealers is highly recommended in patients with DM owing to their excellent biocompatibility, antibacterial potential and capacity to enhance periapical healing, even in cases with compromised immune response and delayed tissue repair. Achieving a dense 3D obturation is equally critical to prevent microleakage and bacterial persistence.⁶

Restorations should be carefully designed to maintain an effective ferrule, providing structural reinforcement and protecting the weakened root dentine, which is more susceptible to fracture in patients with DM owing to altered mechanical and mineral properties. Timely and well-sealed coronal restoration is essential to prevent microbial reinfection, as individuals with DM exhibit an increased vulnerability to bacterial invasion and compromised defence mechanisms against recurrent infection.^8, 9

Follow-up and monitoring
Regular follow-up is essential for evaluating healing progression after endodontic treatment in patients with DM. Clinical and radiographic assessments should be scheduled at six and 12 months, but it should be considered that radiographic healing may be slower or incomplete in cases of poor glycaemic control. In some patients, periapical healing may extend beyond 18 months, warranting prolonged observation for any signs of persistent lesions. Throughout the follow-up period, clinicians should reinforce the importance of maintaining optimal glycaemic control, as metabolic stability plays a critical role in promoting successful periapical repair. Close interdisciplinary collaboration with the patient’s medical team is strongly recommended to support systemic and oral health outcomes.^5, 7

Conclusion

DM profoundly influences endodontic outcomes, primarily by impairing pulpal and periapical healing through microvascular compromise and immune dysregulation. Achieving predictable success in these patients requires comprehensive assessment, adherence to minimally invasive techniques and the strategic use of bioactive materials that support tissue regeneration. Interdisciplinary collaboration with medical professionals and meticulous long-term follow-up are essential to optimise both systemic and endodontic outcomes. Continued clinical and translational research is crucial to refine evidence-based protocols and deepen our understanding of this complex and clinically significant relationship between DM and endodontic disease.

Editorial note:

This article was published in roots–international magazine of endodontics vol. 21, issue 2/2025. The list of references can be found here.