Assessment of the correlations between nicotine dependence, exhaled carbon monoxide levels and oral hygiene status: an observational study

BACKGROUND AND AIM: Cigarette smoking has negative effects on general health, including oral health. The aim of our study was to assess the correlations between nicotine dependence, exhaled carbon monoxide levels and oral hygiene status. METHODS: Smoker and non-smoker participants were enrolled in this observational study. The Fagerström test was used to classify nicotine dependences: low (score: 0–3), medium (score: 4–6) or high (score: 7–10). The oral hygiene status was classified according to the oral hygiene indices of plaque, calculus and gingival inflammation. Lastly, the exhaled carbon monoxide levels were measured with a MicroSmokelyzer (Bedfont Scientific Ltd., Kent, United Kingdom). RESULTS: Sixty five participants (50 smokers in the study group and 15 non-smokers in the control group) were enrolled between 11th and 29th of January 2016. No statistical differences were observed between the study group and the control group in terms of age (mean age±SD 23.5±1.9 and 24.0±1.5, respectively) or gender (50% and 26.6%, respectively). A statistically significant difference was observed between the 2 groups in terms of plaque, (p=0.036), calculus (p=0.001) and gingival indices (p<0.001). A positive correlation was found between the exhaled levels of carbon monoxide and the general Fagerström score (r=0.97, p<0.001) or the Fagerström score in smokers (r=0.93, p<0.001); a negative correlation was observed between the exhaled carbon monoxide levels and the number of tooth brushings daily (r=−0.41, p=0.001). The plaque index was statistically significantly associated with the exhaled carbon monoxide levels (p=0.008), general Fagerström score (p=0.016) and number of tooth brushings daily (p<0.001). The calculus and gingival indices were statistically significantly associated with the exhaled carbon monoxide levels (p<0.001), general Fagerström score (p<0.001) and score in smoker participants (p=0.029 and p=0.001, respectively) as well as the number of tooth brushings daily (p<0.001). CONCLUSION: Our study found a significant association between the plaque, calculus and gingival indices and smoking. Moreover, nicotine dependence was significantly associated with the number of daily tooth brushings and the gingival index.