T.J. Lasisi1 and A.A. Fasanmade2

  1. Department of Physiology, University of Ibadan, Ibadan.
  2. Department of Medicine, Endocrinology Unit, University College Hospital, Ibadan.


Background: A high incidence of periodontal disease has been reported among diabetics, however the role of saliva in the occurrence of this oral disease in these patients is yet to be understood.

Objective: To determine the effects of type-2 diabetes and periodontal disease on salivary flow rate and biochemical composition.

Design: A prospective study involving 40 adult human subjects divided equally into four groups of diabetics with periodontitis (group 1), diabetics without periodontitis (group 2), non diabetics with periodontitis (group 3) and non diabetics without periodontitis (group 4).

Methodology: Saliva samples were collected and analyzed for salivary glucose, total protein, calcium, sodium, potassium, chloride and bicarbonate. Salivary flow rates were also determined.

Results: Salivary glucose and potassium levels were significantly higher (P = 0.002 and 0.04 respectively) in diabetic patients regardless of periodontal disease (mean = 100.7 ± 9.33 mg/dl; 111.5 ± 32.85 mg/dl and 23.79 ± 5.19 mg/dl; 22.9 ± 6.25 mg/dl respectively) compared with non diabetic participants (mean = 80.5 ± 30.85 mg/ dl; 62.5 ± 31.89 mg/dl and 19.23 ± 5.04 mg/dl; 17.74 ± 4.68 mg/dl respectively). In contrast, there was no significant difference in saliva
flow rates and levels of total protein, Na+, Ca++, Cl- and HCO3 – between the groups.

Conclusion: Salivary glucose and potassium levels were significantly higher among diabetics with or without periodontitis compared with non-diabetics with or without periodontitis. However, biochemical composition of saliva in diabetic individuals has probably little role in their susceptibility to periodontitis.

Keywords: periodontitis, type 2 diabetes mellitus, salivary electrolytes, salivary glucose.


Dr. Taye J. Lasisi
Department of Physiology,
University of Ibadan, Ibadan


The role of saliva in oral health has been a subject of continued research1,2. However, the study of salivary functions has been challenging because of the high physiological variability of this fluid when compared to other body fluids such as plasma3,4.

Several systemic diseases affect oral health and diabetes mellitus is an established risk factor for periodontitis. 5 Most studies reported that periodontitis and xerostomia are common complications of both insulin dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM)6,7,8. These oral complications have been attributed to diminished flow of saliva resulting from systemic dehydration and an increase in the salivary glucose level8-10. A wide range of underlying pathogenic factors has been postulated to explain the increased prevalence and severity of periodontitis11,12 observed in diabetes but the role of salivary composition has not been fully studied. Furthermore, little is known concerning the relationship between diabetes and salivary biochemical parameters and the effect of these changes on oral health. In addition, despite the fact that periodontitis is highly prevalent among diabetics, most studies do not relate the salivary composition in diabetic patients to periodontitis.

The aim of this study was to determine the effects of diabetes and periodontal disease on salivary flow rate and biochemical composition.

Study Design
This is a prospective study involving 40 adult human subjects divided equally into four groups of diabetic with periodontitis (group 1), diabetic without periodontitis (group 2), non diabetic with periodontitis (group 3) and non diabetic without periodontitis (group 4).

The diabetic subjects were consecutive patients attending the Endocrine Unit of the Medical Out Patients Department, University College Hospital, Ibadan, while non diabetic subjects were members of the University of Ibadan community.

Participants were provided information regarding risks and benefit of the study and consents were taken. Diagnosis of periodontal disease was based on findings using the attachment loss scoring system (CPI Index). Subjects with periodontal indices of > 3 were considered as having periodontitis while those with periodontal indices of < 2 were considered as not having periodontitis.

The study received ethical clearance and approval from the Joint University of Ibadan/University College Hospital Health Research Ethical Committee.

Saliva collection
Saliva collection was undertaken between 8am and 9am and participants were instructed to observe overnight fast (last meal not later than 12 midnight). Un-stimulated saliva was collected by the spitting method13. Participants were asked to spit (after rinsing the mouth with deionized water) into calibrated universal plastic bottles for a period of 10 minutes. Rates of resting saliva secretions were expressed in mls/mins.

Immediately after collection, the bottles were examined to determine the volume and stored at -200C until used for laboratory analysis. Samples were defrosted at room temperature and then centrifuged at 6000 rpm for 10 minutes before being used in order to remove contaminants such as oral epithelial cells, micro organisms and food debris among others.

Salivary ions analysis
The saliva collected was analyzed for the concentrations of K+, Na+, Ca2+, Cl- and HCO3 -2.

For the determination of salivary ions, saliva was diluted at either 1/100 or 1/1000 and K+, Na+ and Ca2+ concentrations were determined using flame emission spectrophotometry14. Concentrations of Cland HCO3 2- were determined by Schale’s method using mercuric nitrate15.

Salivary glucose analysis
This was carried out by the glucose oxidase method using 4-Aminophenazone as oxygen acceptor16.

Salivary analysis of total protein
Saliva samples were defrosted at room temperature and then centrifuged at 6000 rpm for 10 minutes before use. Total protein concentration expressed as mg/dl was determined using established colorimetric methods with the use of Helios spectrophotometer by reading samples at 720nm. Bovine serum albumin was used for calibration purposes17.

Statistical analysis
All statistical analyses were carried out using SPSS Version 16. The Analysis of Variance (ANOVA) and Duncan tests were employed to evaluate differences within and between the groups. A p-value of 5% was considered to be statistically significant.