Evaluation of oral mechanical and gustatory sensitivities and salivary cotinine levels in adult smokers.

Objective: The aim was to examine oral mechanical and gustatory sensitivities in adult smokers and to estimate salivary levels of cotinine by tobacco consumption. A total of 54 adults (20-45 years old; 28 males/26 females) were divided into two sex-paired groups: smoker group (n = 27), tobacco consumers with no other chronic disease/use of chronic medication, and a control non-smoker non-exposed group with similar age (n = 27).Materials and Methods: 24 h-Recall was used to gather information about tobacco consumption, date of onset and duration of the habit. Oral mechanical evaluation comprised touch detection threshold (MDT) of upper and lower lips and tongue tip and two-point discrimination (TPD) assessments. Taste sensitivities for sweet, salty, sour and bitter were evaluated in four concentrations. Salivary cotinine was determined by high performance liquid chromatography. Statistical analysis comprised Mann-Whitney, Two-way ANOVA test and regression analysis.Results: The mean smoking time was 13.6 years (mean 8.4 mg/day; 13 cigarettes/day). A sex-effect was observed on MDT of tongue tip (higher sensitivity in females), while group-effect was observed on TPD of lower lip, showing a smaller sensitivity among smokers (p < .05; moderate effect: Eta partial2 = 0.076). Although the total score of gustatory sensitivity did not differ between groups, smokers exhibited an irregular pattern of correctly identified tastants among the different concentrations of salty, sour and bitter. The predictive model showed that salivary cotinine was dependent on "nicotine consumption on the day before" (R2 = 49%).Conclusion: A difference in tactile sensitivity of the lower lip and qualitative changes in taste sensitivity were observed in smokers.