[ELISA analysis of salivary cotinine in smokers].

Background: The presence in saliva of cotinine, the main and inactive metabolite of nicotine, reflects the extent of systemic distribution of nicotine and explains the increased susceptibility to periodontal disease in smokers. The aim of this study was to investigate the comparative amount of cotinine in the saliva of habitual cigarette smokers, non-smokers and passive smokers.

Methods: Saliva sample were obtained from 14 cigarette smokers and 13 non-smokers (8 passive-smokers), all without periodontal disease, and analyzed by Microplate EIA (a variation of ELISA based on cross-reactivity of cotinine with anti-cotinine antibody revealed by absorbance in spectrophotometry) to determine the presence and the amount of cotinine.

Results: Cotinine was detected in the saliva of smokers with a mean of 92.3 +/- 4.15 ng/ml and, unexpectedly, there was evidence of cotinine also in the saliva of non-smokers (mean 5.4 +/- 1.22 ng/ml), particularly, in passive-smokers (mean 12.9 +/- 6.67 ng/ml).

Conclusions: The salivary concentration of cotinine can be used to estimate nicotine intake and its possible role in the pathogenesis of periodontal disease also in passive-smokers.