International Journal of Oral Health Sciences

: 2019  |  Volume : 9  |  Issue : 1  |  Page : 15--19

Relationship of salivary levels of sialic acid in obese patients with chronic periodontitis: A biochemical study

Vivek Kumar1, Amrita2, Gargee Rawat3, Mahendra Pratap4, Gaurav Kumar4, Anshul Verma5,  
1 Department of Periodontology, Hazaribag College of Dental Sciences and Hospital, Hazaribag, Jharkhand, India
2 Department of Periodontology, Uttaranchal Dental and Medical Research Institute, Dehradun, Uttarakhand, India
3 Department of Endodontics and Conservative Dentistry, Uttaranchal Dental and Medical Research Institute, Dehradun, Uttarakhand, India
4 Department of Orthodontics and Dentofacial Orthopedics, Uttaranchal Dental and Medical Research Institute, Dehradun, Uttarakhand, India
5 Department of Prosthodontics and Crown and Bridge, Uttaranchal Dental and Medical Research Institute, Dehradun, Uttarakhand, India

Correspondence Address:
Dr. Vivek Kumar
House No. 308/A, Prasad Flour Mill Road, Doranda, Ranchi, Jharkhand


Background: Sialic acid (SA) participates in multiple physiological functions, such as cell-to-cell interactions, cell migration, and proliferation. The levels of SA may provide intimation about the severity and state of underlying disease processes. Hence, the aim of the present study was to assess the salivary levels of SA in obese patients with and without chronic periodontitis (CP) and nonobese healthy patients. Materials and Methods: A total of 45 patients were divided into three groups: Group 1: nonobese healthy, Group 2: obese without CP, and Group 3: obese with CP. Whole saliva samples were collected, and SA levels were evaluated using the thiobarbituric acid method of Skoza and Mohos. The results were analyzed using SPSS and Mann–Whitney analysis. Results: The highest SA levels from the saliva were detected in Group 3 while the lowest in Group 1. A significant difference in SA levels in the saliva was found when Groups 1 and 2 were compared with Group 3 (P < 0.0001). Conclusion: The level of SA was higher in the saliva of CP patients. SA may be used as an inflammatory marker for the detection of periodontal disease.

How to cite this article:
Kumar V, Amrita, Rawat G, Pratap M, Kumar G, Verma A. Relationship of salivary levels of sialic acid in obese patients with chronic periodontitis: A biochemical study.Int J Oral Health Sci 2019;9:15-19

How to cite this URL:
Kumar V, Amrita, Rawat G, Pratap M, Kumar G, Verma A. Relationship of salivary levels of sialic acid in obese patients with chronic periodontitis: A biochemical study. Int J Oral Health Sci [serial online] 2019 [cited 2020 Jan 23 ];9:15-19
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Periodontitis is an infectious condition caused by periodontal pathogens, which affects the composition and integrity of periodontal structures and causes destruction of cells and connective tissue matrix, clinical attachment loss (CAL), alveolar bone resorption, periodontal pocket formation, and gingival inflammation.[1],[2] The association between periodontal disease and systemic conditions appears to be attributable to a low-grade inflammatory burden that links them through a common pathophysiologic mechanism.[3] Although microorganisms are implicated as the primary etiological agent causing altered inflammatory response, typical are the chemical mediators of inflammation, namely cytokines, eicosanoids, and matrix metalloproteinase, which play a critical role in the loss of connective tissue and supporting alveolar bone.[4]

The World Health Organization (WHO) has recognized obesity as a predisposing factor for major chronic diseases ranging from cardiovascular disease to cancer. Obesity is characterized by the presence of chronic subclinical inflammation with increased concentration of pro-inflammatory mediators.[5] It is a condition similar to overall inflammation, occurring with metabolic and immune characteristics, rendering one susceptible to periodontal disease.[6]

Saliva is used as a diagnostic tool to evaluate various biomarkers associated with periodontal disease.[7] Assessment of the composition of saliva may provide valuable information about biochemical markers for the assessment of periodontal diseases.[8]

Sialic acids (SAs) are the family of nine-carbon acidic monosaccharide that occurs naturally at the end of sugar chains attached to the surface of cells and soluble proteins.[9] SA participates in multiple physiological functions, such as cell-to-cell interactions, cell migration, and proliferation.[10] An important function of host SA is to regulate innate immunity. It occupies the interface between host and pathogenic microorganisms. Microorganisms incorporate SA into their cell surface, which helps them evade innate immune response of the host.[11] SA is present in several acute-phase proteins which are known to be associated with periodontitis.[12]

In the light of above facts, the current study was undertaken with an aim to assess the level of salivary SA in obese patients with and without chronic periodontitis (CP) and nonobese healthy patients.

 Materials and Methods

This case–control, cross-sectional study was performed from January 2017 to July 2017 in the Department of Periodontology after obtaining ethical approval from the institutional review board of the college. A total of 45 male and female participants aged between 25 and 50 years participated in this study. Written informed consent was obtained from all the participants before the start of the study.

Anthropometric measurement

Measurements were taken uniformly according to a standard protocol. Body mass index (BMI) was calculated as the ratio of body weight (kg) divided by square of the height (m). Obesity is usually defined as BMI. Overweight is defined as BMI between 25.0 and 29.9 kg/m2, and obesity is defined as BMI of ≥30.0 kg/m2.[13]

The WHO STEPS protocol for measuring waist circumference (WC) instructs that measurement be made at the approximate midpoint between the lower margin of the last palpable rib and the top of iliac crest. WC is used to measure the body fat distribution; the cut-off point for abdominal obesity in men was kept at 102 cm and in women 88 cm. The waist–hip ratio (WHR) was calculated as WC (cm) divided by hip circumference (cm).[14]

The participants were categorized into three groups based on gingival index (GI), pocket probing depths (PPD), BMI, and WC.

Group 1 (healthy) consisted of 15 individuals with healthy gingiva of probing depth ≤3 mm and a GI ≤1 mm and CAL = 0Group 2 (obese with healthy gingiva) consisted of 15 individuals (BMI ≥30.0) with healthy gingiva of probing depth ≤3 mm and a GI ≤1 mm and CAL = 0Group 3 (obese with CP) consisted of 15 (BMI ≥30.0) individuals who had signs of clinical inflammation, presence of at least 12 teeth, excluding third molars, and a diagnosis of CP with GI >1 and PPD ≥5 mm and CAL ≥3 mm.

Exclusion criteria

Cigarette smoking or tobacco use and alcoholismSystemic diseases such as diabetes mellitus, hypertension, and rheumatoid arthritisPregnancySystemic bacterial, viral, or fungal infectionHistory of antibiotic therapy or use of anti-inflammatory medications during the past 6 monthsPeriodontal therapy during the past 2 yearsPatients with a diagnosis of aggressive periodontitis.

Sample collection

Participants were requested to refrain from eating and drinking for at least 2 h before saliva collection. Using the spitting method, unstimulated saliva was collected between 11:00 am and 13:00 pm for 5 min (one spit per minute). The saliva was collected in sterile tubes, the samples were centrifuged at 3000 rpm for 10 min, and the supernatant was analyzed. The samples were stored at −70°C until the experiment. SA content was determined by a combined modification of the thiobarbituric acid method of Skoza and Mohos.[15] The samples (100 μl) were treated with 70 μl of periodate reagent and incubated at 37°C for 30 min. The reaction was terminated through the addition of 70 μl of sodium arsenite; then, 140 μl of thiobarbituric acid (0.1M) was added and this solution was heated in a boiling water bath for 7.5 min and then cooled in ice water up to room temperature. Dimethyl sulfoxide (560 μl) was added, and the solutions were measured on a spectrophotometer at a wavelength of 549 nm. Total SA content in the saliva and serum was measured in mg/dl.

Data analysis

Statistical analyses were performed using SPSS software version 21 (SPSS Inc., Chicago, IL, USA). The salivary levels of SA were compared between two groups using the Mann–Whitney and t-test. P < 0.05 was considered statistically significant. Data were presented as mean ± standard deviation (SD).


The mean values of clinical and biochemical parameters were expressed as mean ± SD [Table 1]. The highest SA levels from saliva were detected in Group 3 (88.54 ± 4.47 mg/dl) while the lowest were detected in Group 1 (38.04 ± 3.28 mg/dl) [Graph 1].{Table 1}[INLINE:1]

Intergroup comparisons of clinical and biochemical parameters are summarized in [Table 2]. A significant difference in SA in the saliva was found when Group 1 was compared with Group 3 (P < 0.0001) and Group 2 was compared with Group 3 (P < 0.0001). Statistically significant differences were observed when the comparison of GI and PPD scores was made with Groups 1 and 2 versus the periodontally diseased Group 3. A significant difference in BMI, WC, and WHR was found when Group 1 was compared with Groups 2 and 3.{Table 2}


The potential role of saliva in the diagnosis of oral and systemic health is evident in researches. Salivary biomarkers could be used to screen periodontal health status and disease progression.[16],[17] Saliva is the first defense fluid, and an important salivary biomarker is SA which is a family of nine-carbon acidic monosaccharide, systemic inflammatory markers, and component of salivary glycolipids, glycoproteins, including IgA, and other immunological and acute-phase proteins.[18] SA is a marker of acute-phase response and predictor of several systemic disorders, cardiovascular events, rheumatoid arthritis, and diabetes.[19],[20]

The results of the present study revealed that the mean salivary SA level of Group 3 was higher than that of Groups 1 and 2. The increased levels of SA in periodontitis patients were attributed to the fact that the presence of certain Gram-negative bacteria (periodontopathogenic) adheres only to low molecular weight and free form of salivary mucin throughout the SA residues present on low molecular weight of mucin which may cause an increase in SA.[21] Second, high mean concentrations of SA might be attributed to the rapid synthesis of sialoproteins and to a significant increase in the release of globulins, resulting from tissue damage.[22] The finding in this study is in accordance with the studies conducted by Davis and Gibbons,[23] Shinohara et al.,[24] Jawzaly et al.,[25] and Rathod et al.[26] Ogasawara et al.[27] concluded that SA of mucin acts as scavengers for hydroxyl free radical and reacts directly with it. SA concentration increases rapidly following the inflammatory and injury processes. Elevated levels of SA in the saliva and serum may have a protective role in periodontitis as elevated levels of total sialic acid might be considered as a defense molecule against the increased oxidative stress in inflammatory diseases including periodontitis.

Patients in Groups 1 and 2 showed no statistically significant difference when the GI and PPD were compared. Statistically significant difference was observed when Groups 1 and Group 2 were compared with Group 3 (P < 0.0001). A mean probing depth of 6.80 ± 1.21 mm and a GI score of 2.32 ± 0.49 mm in Group 3 established the presence of an active inflammatory component along with a destructive component to the prevalent periodontal disease.

The salivary SA levels were correlated with obesity measures such as BMI, WC, and WHR, but this correlation was not significant in Groups 1 and 2. Further, a significant difference was noted in salivary SA levels when Groups 1 and 2 were compared with Group 3. Thus, salivary SA levels increased with periodontal inflammation, but obesity did not affect the levels significantly when compared among the groups. In this study, the increase in salivary SA level in obese patients with periodontitis could be enhanced by the preexisting active inflammation (CP).


At present, there are several biomarkers studied in relation to periodontitis and obesity. However, there are very few studies addressing the relationship between CP and SA. In the current study, the level of SA was higher in the saliva of CP patients. SA may be used as an inflammatory marker for the detection of periodontal disease. The limitation of this study was that we did not have information about the level of SA after treatment of periodontitis. Further long-term and interventional studies with larger sample sizes are required to assess the efficacy of this biomarker for early detection of periodontal disease and prevention of its progression. Finally, for considering SA as a biomarker of inflammation in periodontitis, further studies are needed with more sample size in different populations.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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