Assessment of lingual nerve functions after smoking cessation

Objective: Cigarette smoking is associated with a variety of oral diseases. A previous study showed a reduction of thermal sensitivity in the innervation area of the lingual nerve in smokers possibly caused by a degeneration of thermosensitive receptors as a consequence of smoking. The current study investigates somatosensory changes in ex-smokers. Materials and methods: Sensory functions in innervation areas of lingual nerve were investigated in 40 ex-smokers by psychophysical means. Functions of lingual nerve in 40 ex-smokers were compared to those in 40 smokers and 40 non-smokers. Subjects were investigated using quantitative sensory testing (QST, cold and warm detection, thermal sensory limen, heat and cold pain, and mechanical detection). Results: Significant differences were found in both groups, ex-smokers and smokers compared to non-smokers. Cold (p < .001), warm (ex-smokers: p < .01; smokers: p < .001) detection thresholds and thermal sensory limen (p < .001) showed significantly lower sensitivity in ex-smokers and smokers in comparison to non-smokers. Conclusions: The lower temperature sensitivity of ex-smokers compared to that in non-smokers indicates a reduction of somatosensory function of the tongue, possibly caused by irreversible nerve degeneration associated with smoking. Influencing factors leading to sensory changes could be modulation of thermo-receptors, demyelination as well as a change of the epithelial structure.