Determination of sialic acid levels by using surface-enhanced Raman spectroscopy in periodontitis and gingivitis

Objectives To compare the sialic acid (SA) levels in saliva among periodontitis-affected, gingivitis and control patients. Methods The study involved 93 subjects. The participants were divided into three groups: (1) 30 subjects without periodontal disease (control group); (2) 30 subjects with gingivitis; and (3) 33 subjects with periodontitis. The oral parameters examined were as follows: (a) Simplified Oral Hygiene Index; (b) Calculus Index; (c) Gingival Index; (d) probing pocket depth; and (e) level of epithelial attachment. SA levels in saliva were measured by means of surface-enhanced Raman spectroscopy (SERS). This method has demonstrated the capacity to detect extremely low concentrations of molecules. The spectrum was calibrated using analytical reagent SA. Results The obtained median values for SA concentrations were 5.98, 7.32, and 17.12 mg/dl for control, gingivitis, and periodontitis patients, respectively. Conclusions Our measurements by SERS corroborate that in periodontitis-affected patients, the SA concentration is larger than their concentrations in either control or gingivitis patients. This confirms previous reports and opens the possibility of using SERS as a diagnostic tool.