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For Patients & Visitors

The Unsweetened Truth about Diabetes and Periodontal Disease

By Dr Jacinta Lu
12/3/2018 12:00 AM

"Do you have diabetes or a family history of diabetes? When was your last blood sugar check?" Dentists are often greeted with a puzzled look on patients' faces whenever these questions were being asked. Patients are often perplexed as to why dentists have such a keen interest in their medical health.

Diabetes mellitus is a growing worldwide health problem and its prevalence is increasing dramatically[1]. In light of this global epidemic of type 2 diabetes in particular, nationwide efforts have been stepped up to curb diabetes in recent years and there is a notable increase in public awareness with regards to diabetes as a chronic disease and its associated microvascular and macrovascular complications.

However, what is lesser known is that such long-term complications that may occur in type 1 and type 2 diabetes could have oral manifestations (Table 1). Multiple epidemiological studies have demonstrated that both variants of diabetes are predictors of periodontal disease when the systemic condition is poorly controlled. Hence apart from the five well recognised complications of diabetes, namely retinopathy, neuropathy, nephropathy, cardiovascular disease and peripheral vascular disease, periodontitis has been identified as the sixth complication of this condition[2].

Table 1

Long-term diabetic complication: Microvascular disease
Oral Implications: 

  • Xerostomia
  • Greater susceptibility of oral tissues to trauma
  • More opportunistic infections ( e.g. candidiasis)
  • Greater accumulation of dental plaque which may confer higher risk of caries and periodontal disease development and progression
  • Delayed wound healing

Long-term diabetic complication: Peripheral neuropathy
Oral Implications:

  • Oral paresthesia, including burning mouth or tongue
  • Altered taste sensations

Adapted from Rees[3]

What is periodontal disease?

Periodontal disease, also known as gum disease, is one of the most common dental conditions that specifically affect the supporting structures of the tooth/teeth. It is initiated and sustained by an aberrant host immune response against bacterial biofilm on the teeth in disease susceptible individuals[4]. It has also been identified as one of the two significant global burdens of oral diseases by the World Health Organisation.

At the initial stage, the inflammation in response to accumulation of bacteria is restricted within the gingiva/gums giving rise to gingivitis. Patients with gingivitis often complain of bleeding gums. As the condition is usually painless at this stage, patients tend to choose to overlook this early warning sign. As the disease progresses to a more severe state, known as periodontitis, the connective tissue attachment around the tooth and the underlying supporting alveolar bone are destroyed over time, leading to a reduction in tooth support and eventual tooth loss. According to the Singapore Health Survey conducted in 2003, about 85% of the local population suffer from mild to moderately severe periodontal disease. The global prevalence of severe periodontitis (presence of gum pocketing ≥6 mm) is generally estimated to be around 5-15% of adults[5].

Association between diabetes and periodontal disease

Although diabetes and periodontal disease may seem to be very different chronic inflammatory diseases of different etiologic origins, the association between these two common diseases has been recognised by dental professionals for many years. Several studies have demonstrated that diabetes mellitus severely exacerbates the onset, progression and severity of periodontitis[6,7]. The prevalence of periodontitis in patients with diabetes is estimated to be two to three times higher than in an otherwise healthy population[8]. Patients with diabetes, particularly those with uncontrolled diabetes, are more susceptible to infections and impaired wound healing;[9]therefore, periodontitis is considered to be a complication of diabetes mellitus.

Furthermore, diabetics with untreated periodontal issues generally have poorer metabolic control of their blood sugar levels. Control of severe, long-standing inflammatory periodontal infection in diabetic patients has been shown to reduce the levels of advanced glycation products (AGEs) in the serum[10]. However, even though there seems to be a positive association between periodontal treatment and improved metabolic control of diabetes, the key factor appears to be still the level of glycemic control. A three-year follow up study on diabetics and non-diabetics revealed that the level of periodontal health in diabetic patients with good or moderate control of their condition was similar to that in the non-diabetic controls. Those with poor control had more periodontal attachment loss and were more likely to exhibit recurrent disease[11]. Therefore, in view of the current evidence, prevention and control of periodontal disease must be considered as an integral part of diabetes control.


With the knowledge of the bidirectional inter-relationship between these two diseases, it has been advocated that dentists could help screen for pre-diabetes through the assessment of glycated haemoglobin (HbA1c) in the blood. At National University Hospital (NUH), patients presenting with severe forms of periodontal disease are educated and encouraged to go for point-of-care testing (POCT) HbA1c screening to check on their blood sugar status. Upon receipt of the results, patients with suspected pre-diabetic conditions or abnormally elevated HbA1c levels will be directed to the endocrinologist for further investigations.

Conversely, medical practitioners can recommend their patients who have been diagnosed with diabetes to go for a dental screening. Periodontal disease is known to be a 'silent killer' as symptoms may not appear until an advanced stage of the disease. Early recognition of the disease is crucial, so that timely management and intervention can be instituted to effectively prevent tooth loss, which has an inherent downstream impact on esthetics, function, quality of life and cost to the patient.

Warning signs of periodontal disease include the following:

  • Red, swollen or tender gums or other oral pain
  • Bleeding while brushing, flossing, or eating hard food
  • Receding gums
  • Mobile teeth with or without pathological migration of teeth
  • Suppuration, dental abscesses
  • Halitosis[12]

Upon identification of the presence of periodontal disease, the dentist, doctor and the patient have to work hand in hand to optimise patient's glycemic and oral disease control. The principles of treatment of periodontitis in diabetic patients are the same as those for non-diabetic patients and are consistent with our approach to all high-risk patients who already have periodontal disease. Treatment modalities include scaling and root planing, gum surgery and dental extractions of teeth with hopeless prognosis. Diabetic patients with poor metabolic control will be attended to more frequently, especially if periodontal disease is already present.

At the same time, efforts are also directed at preventing the development and/or progression of gum disease in patients who are at risk of diabetes or diabetics with no current dental issues. Prevention measures include oral hygiene instructions and placement on a regular periodontal maintenance schedule.

Classic clinical presentation of periodontal disease


1. Lam DW, LeRoith D. The worldwide diabetes epidemic. Curr Opin Endocrinol Diabetes Obes 2012;19:93–6.

2. Löe H. Periodontal Disease: The sixth complication of diabetes mellitus. Diabetes Care Jan 1993, 16 (1) 329-334

3. Rees TD. Periodontal management of the patient with diabetes mellitus. Periodontol 2000; 23(1):63-72

4. Pihlstrom  BL, Michalowicz  BS, Johnson  NW. Periodontal diseases. Lancet 2005;366:1809–20.

5. Dye B A. Global periodontal disease epidemiology. Periodontol 2000 2012; 58: 10–25.

6. Lalla  E, Papapanou  PN. Diabetes mellitus and periodontitis: a tale of two common interrelated diseases. Nat Rev Endocrinol 2011;7:738–48.

7. Mealey  BL, Rose  LF. Diabetes mellitus and inflammatory periodontal diseases. Curr Opin Endocrinol Diabetes Obes 2008;15:135–41.

8. Mealey  BL, Oates  TW. American Academy of Periodontology. Diabetes mellitus and periodontal diseases. J Periodontol 2006;77:1289–303.

9. Muller  LM, Gorter  KJ, Hak  E, et al. Increased risk of common infections in patients with type 1 and type 2 diabetes mellitus. Clin Infect Dis 2005;41:281–8.

10. Grossi SG, Skrepcinski FB, DeCaro T, Robertson DC, Ho AW, Dunford RG, and others. Treatment of periodontal disease in diabetics reduces glycated hemoglobin. J Periodontol 1997; 68(8):713-9.

11. Tervonen T, Karjalainen K. Periodontal disease related to diabetic status. A pilot study of the response to periodontal therapy in type 1 diabetes. J Clin Periodontol 1997; 24(7):505-10.

12. Adapted from

Dr Jacinta Lu
Associate Consultant
Division of Periodontics
National University Centre for Oral Health, Singapore (NUCOHS)

Dr Lu obtained her dental degree from National University Singapore (NUS) and was awarded the Singapore Dental Association President's Bronze Medal and Dean's list twice. She completed her specialist training in Singapore and holds a Master of Dental Surgery (Periodontology). She is currently a fellow of Royal College of Surgeons of Edinburgh and holds a joint teaching appointment as Assistant Professor at NUS and Adjunct Lecturer at Nanyang Polytechnic (NYP) and Institute of Technical Education (ITE).

Dr Lu provides a comprehensive range of periodontal therapies and has special interest in the treatment of medically compromised patients and dental phobics.