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 Table of Contents  
Year : 2022  |  Volume : 66  |  Issue : 2  |  Page : 206-209  

Dental caries and their relation to hba1c in adults with type 2 diabetes mellitus

1 Oral and Maxillofacial Pathologist, Dental Department, Dr. Mohan's Diabetes Specialities Centre, Chennai, Tamil Nadu, India
2 Prosthodontist, Dental Department, Dr. Mohan's Diabetes Specialities Centre, Chennai, Tamil Nadu, India
3 Oral and Maxillofacial Surgeon, Dental Department, Dr. Mohan's Diabetes Specialities Centre, Chennai, Tamil Nadu, India
4 Dental Consultant, Dental Department, Dr. Mohan's Diabetes Specialities Centre, Chennai, Tamil Nadu, India
5 Scientist & Head, Department of Childhood and Youth Onset Diabetes, Madras Diabetes Research Foundation, Chennai, Tamil Nadu, India

Date of Submission16-Oct-2021
Date of Decision29-Apr-2022
Date of Acceptance02-May-2022
Date of Web Publication12-Jul-2022

Correspondence Address:
Sukanya Saravanan
Dental Consultant, Dr. Mohans Diabetes Specialities Centre, Chennai, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijph.ijph_1935_21

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Diabetes mellitus with poor glycemic control is often associated with dental caries. We aim to assess the relationship between dental caries and HbA1c levels among adults with type 2 diabetes (T2D) in Chennai. A cutoff of HbA1c ≥7.0 to 7.9% (53–63 mmol/mol) was used to define Group 1 (n = 113) as moderately controlled and HbA1c ≥8.0% (64 mmol/mol) to define Group 2 (n = 228) as poorly controlled T2D. The absolute numbers of decayed, missing, and filled teeth were examined to calculate the decayed, missing and filled teeth index. Group 2 had a significantly higher percentage (48.2%) of decayed teeth when compared to Group 1 (28.3%). Group 2 had a 2.65 times higher risk of decayed teeth when adjusted for mean carbohydrate consumption, sweets consumption, oral hygiene, and brushing habit. T2D with higher HbA1c levels is associated with an increased number of decayed teeth. Hence, there is a need for monitoring dental status in T2D as earlier treatment may prevent or delay decay teeth.

Keywords: Adults, decayed ,missing and filled teeth index, decayed teeth, glycated hemoglobin, India

How to cite this article:
Mohan D, Bhuvaneshwar Y, Jeyaram RM, Saravanan S, Amutha A, Research Team. Dental caries and their relation to hba1c in adults with type 2 diabetes mellitus. Indian J Public Health 2022;66:206-9

How to cite this URL:
Mohan D, Bhuvaneshwar Y, Jeyaram RM, Saravanan S, Amutha A, Research Team. Dental caries and their relation to hba1c in adults with type 2 diabetes mellitus. Indian J Public Health [serial online] 2022 [cited 2022 Aug 13];66:206-9. Available from:

Research team:
Radhakrishnan Subashini6
6Dental Department, Dr. Mohan′s Diabetes Specialities Centre, Chennai, India.

Ranjit Mohan Anjana, Viswanathanm Mohan7
7Dr. Mohan's Diabetes Specialities Centre & Madras Diabetes Research Foundation, Chennai, India.

The prevalence of diabetes is increasing all over the world, particularly in developing countries. China and India alone contribute about 40% of all people with diabetes in the world.[1] The human oral cavity and contiguous structures can be affected by diabetes. Both diabetes and dental caries are associated with ingestion of carbohydrates and an increase in insulin deficiency may lead to hyposalivation and an increase in salivary glucose level, leading to dental caries.[2] The present study aimed to assess the relationship between dental caries and glycated haemoglobin (HbA1c) levels among adults with Type 2 diabetes (T2D) seen at a diabetes center in South India.

This study is a retrospective data of 368 consecutive adults with T2D who visited the dental department of a tertiary care center for diabetes in Chennai from October 2017 to December 2017. Of the 368 adults, type 1 diabetes, gestational diabetes women, impaired glucose tolerance, fibrocalculous pancreatic diabetes, adults with no residual teeth, and those who did not do an A1c test (a total of 27 patients) during the visit were excluded from the study. Of the remaining 341, a cutoff of HbA1c ≥ 7.0 to 7.9% (53–63 mmol/mol) was used to define Group 1 as moderately controlled T2D and HbA1c ≥ 8.0% (64 mmol/mol) was considered Group 2 as poorly controlled T2D following the less stringent goals of the American Diabetes Association 2021 standards of medical care in diabetes.[3]

Basic demographic details, anthropometrics, dietary history, and lifestyle habits of all the study participants were recorded. Plasma glucose (hexokinase method) was measured on Beckman Coulter AU2700 Fullerton, California, USA) biochemistry analyzer. HbA1c was estimated by high-performance liquid chromatography using the variant machine (Bio-Rad, Hercules, California, USA). Diabetes was diagnosed if the fasting plasma glucose level was ≥126 mg/dL (7.0 mmol/L) and/or the 2-h postload glucose level was ≥200 mg/dL (11.1 mmol/L) and/or if the participants had been prescribed pharmacotherapy for diabetes by a physician.

Dentists clinically examined adults with T2D following the prestructured case sheet of the dental department. Dental caries was measured visually and no radiographs were taken. The absolute numbers of decayed (DT), missing (MT), and filled teeth (FT) were examined for the participants. DMF-T index is calculated which is a sum of DT + MT + FT. Both filled and crowned teeth were taken as FT. Third molars were included. Met Need Index (MNI) indicates the treatment received by an individual and it was calculated as ([MT + FT]/[DT + MT + FT] X100).[4] Bleeding on probing was considered positive if bleeding occurred within 30 seconds after probing. Periodontal probing was done on each tooth, and the number of teeth with periodontal probing depth ≥4 mm on at least one tooth surface was shown to be associated with periodontitis.[5] Ethical approval of this study was provided by the Institutional Ethics Committee of Madras Diabetic Research Foundation (MDRF/NCT/08-02/2020). Patient written informed consent to use their anonymized medical data was obtained from all study subjects.

All statistical analyses were conducted using SPSS statistical package version 15.0 (SPSS Inc., Chicago, Illinois, USA). Normally distributed continuous variables were summarized as mean ± standard deviation, whereas categorical variables were presented as proportions. Univariate logistic regression was performed with decayed tooth (Y/N) as the dependent variable to identify independent risk factors for a decayed tooth. Multiple logistic regression was conducted to identify the association between the decayed tooth and HbA1c ≥8% while adjusting for carbohydrate consumption, adherence to sweets consumption, oral hygiene index, and brushing habit.

Clinical characteristics, dental caries, and periodontal status of the moderately controlled T2D (Group 1; n = 113) and poorly controlled T2D (Group 2; n = 228) are presented in [Table 1]. The presence of dental caries (48.2% vs 28.3) and the mean number of decayed teeth (1.15±1.7 vs 0.60±1.3) are significantly higher in Group 2 when compared to Group 1. The mean number of DMF-T index was higher among Group 2 than in Group 1, but it does not reach significance. The MNI was lower among Group 2 (P = 0.023). Although the mean value of percentage of teeth with bleeding on probing is higher among Group 2, there was no significant difference (P = 0.110) between the two groups but percentage of teeth with periodontal pocket depth was significant between the two groups (6.55 vs. 9.54; P = 0.010). When compared to Group 1, poor oral hygiene index was higher (3.5% vs. 8.3%) in Group 2.
Table 1: Clinical characteristics, dental caries and periodontal status of adults with type 2 diabetes

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Analysis of food items and macronutrient intake showed that 77.3%, 67.6%, 68.6%, and 45.9% of Group 2 adults consumed more sweets, beverages, nuts, and oils, respectively, when compared to Group 1 (P = 0.027, P = 0.045, P = 0.018, and P = 0.010, respectively). A significant reduction of mean protein (P = 0.019) and fiber (P = 0.030) intake was seen in Group 2. In [Table 2], when adjusted for carbohydrate and sweets consumption, oral hygiene, and brushing habit, Group 2 had (odds ratio: 2.65; confidence interval: 1.50–4.65; P = 0.001) a higher risk of having a greater number of decayed teeth.
Table 2: Multiple logistic regression analysis using decayed teeth as dependent variable

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The study findings indicate that adults with T2D who have HbA1c ≥8.0% have a greater number of decayed teeth than those who have HbA1c ≥7.0%–7.9%. Consumption of sweets and carbohydrates was an additional risk factor along with HbA1c for decayed teeth among adults with T2D.

In our study, the percentage of decayed teeth was more in Group 2 (48.2%), which is similar to a study reported in Tokyo (49.7%).[6] Oral cariogenic organisms such as Treponema denticola, Streptococcus sanguis, Prevotella nigricans, and Streptococcus intermedius were present in the supragingival plaque of poorly controlled T2D patients due to hyposalivation, low salivary calcium level, and upregulated salivary alkaline phosphatase activity.[7] Our study results are in accordance with studies[8],[9] that found a significant association between decayed teeth and HbA1c in adults with T2D.

The MNI was significantly lower in those with poorly controlled diabetes, which suggests that their dental treatment needs were not fulfilled to the same extent as the group with better diabetes control, which is similar to a study done by Yonekura et al.[8] These results concerning MNI suggest that dental intervention for decayed teeth may be beneficial for those with poorly controlled T2D.

A cross-sectional study on 1897 participants revealed a significant association between decayed teeth and HbA1c levels in T2D adults with an HbA1c of ≥8.0% compared to those with a lower value even after adjusting for dental attendance.[6] However, in our study, an association with uncontrolled diabetes was seen even after adjusting for carbohydrate consumption along with sweets adherence, oral hygiene, and brushing habits.

There are several studies done in India relating diabetes mellitus with periodontitis[10] and dental caries[6],[8] between the diabetic and nondiabetic populations. The novelty of the study lies in the fact that to our knowledge, this is the first clinic-based study done to look at the association between the number of decayed teeth and HbA1c levels in adults with T2D and to link it to the dietary intake and other factors. Most dental patients in India turn up to the dentist only when they are in pain. Till now, there are no criteria for referring a diabetic patient to a dentist by general physicians unless they are symptomatic. Hence, we suggest that HbA1c can be considered as a criteria by the diabetologists and they can enlighten patients with poor glycemic control (HbA1c ≥8.0%) to have a regular dental checkup. This helps to maintain their oral hygiene and aids the patients financially by treating the dental problems at an early stage rather than spending more money for complex and costly dental treatment in a later stage of the oral disease.

One of the limitations of the study is that being a retrospective study, there is a possibility of selection bias. Second, the site of the caries was not taken into account namely whether it is coronal or root surface caries. Third, only bleeding on probing and periodontal pocket depth were assessed for the study participants. Finally, we selected only those who had HbA1c ≥7.0%–7.9% as moderately controlled and ≥8.0% as poorly controlled diabetes for the current study outcome and could not assess the association of dental caries in participants with good diabetes control (HbA1c <7.0%), as ADA glycemic target is <7.0%.

Hence, a prospective cohort study with adjustment for confounders including dental examinations (attachment loss, plaque index, gingival index, and alveolar bone resorption) and biological and immunological profile of saliva would throw more light on the association of diabetes with dental caries.

This study suggests that T2D with higher HbA1c levels have an increased number of decayed teeth than those with lower HbA1c levels. Hence, there is a need for monitoring dental status in T2D patients as earlier treatment may prevent or delay decay teeth and also educate them about the association between dental decay and control of diabetes. Thereby, this study calls attention to plan strategies to incorporate dental examination within the existing noncommunicable disease control programs.


The authors thank all the participants in the study and the staff of Dr. Mohans' Diabetes Specialities Centre and Madras Diabetes Research Foundation.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Mohan V. Expanding the concept of “clinical inertia in diabetes. J Diabetol 2019;10:1-3.  Back to cited text no. 1
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Moin M, Malik A. Frequency of dental caries and level of risk among type II diabetics. Dentistry 2015;5:334.  Back to cited text no. 2
American Diabetes Association. 6. Glycemic targets: Standards of medical care in diabetes-2021. Diabetes Care 2021;44:S73-84.  Back to cited text no. 3
Al-Maweri SA, Halboub ES, Al-Soneidar WA, Al-Sufyani GA. Oral lesions and dental status of autistic children in Yemen: A case-control study. J Int Soc Prev Community Dent 2014;4(Suppl 3):S199-203.  Back to cited text no. 4
Loesche WJ, Grossman NS. Periodontal disease as a specific, albeit chronic, infection: Diagnosis and treatment. Clin Microbiol Rev 2001;14:727-52.  Back to cited text no. 5
Suzuki S, Yoshino K, Takayanagi A, Ishizuka Y, Satou R, Nara N, et al. Relationship between blood HbA1c level and decayed teeth in patients with type 2 diabetes: A cross-sectional study. Bull Tokyo Dent Coll 2019;60:89-96.  Back to cited text no. 6
Hintao J, Teanpaisan R, Chongsuvivatwong V, Ratarasan C, Dahlen G. The microbiological profiles of saliva, supragingival and subgingival plaque and dental caries in adults with and without type 2 diabetes mellitus. Oral Microbiol Immunol 2007;22:175-81.  Back to cited text no. 7
Yonekura S, Usui M, Murano S. Association between numbers of decayed teeth and HbA1c in Japanese patients with type 2 diabetes mellitus. Ups J Med Sci 2017;122:108-13.  Back to cited text no. 8
Majbauddin A, Tanimura C, Aoto H, Otani S, Parrenas MC, Kobayashi N, et al. Association between dental caries indicators and serum glycated hemoglobin levels among patients with type 2 diabetes mellitus. J Oral Sci 2019;61:335-42.  Back to cited text no. 9
Sundar C, Ramalingam S, Mohan V, Pradeepa R, Ramakrishnan MJ. Periodontal therapy as an adjunctive modality for HbA1c reduction in type-2 diabetic patients. J Educ Health Promot 2018;7:152.  Back to cited text no. 10


  [Table 1], [Table 2]


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