The Effect of Smoking on Salivary Flow and Antioxidant Capacity

Objective: Smoking is a major risk factor for periodontitis but its impact on oral physiology is unclear. We have investigated the effect of smoking 1 cigarette upon saliva flow and total antioxidant content (TAOC). Methods: Saliva was collected from 40 periodontally healthy individuals (19 males, 21 females), classified by expired air CO analysis as light (<20ppm CO; n=20) or heavy (>21ppm CO; n=20) smokers, before, immediately, 10 and 60 minutes after smoking 1 low tar cigarette (6mg tar, 0.5mg nicotine, 7mg CO; mean self-reported cigarettes/day: 8.9+4.4, light group; 21.7+7.4, heavy group). Volunteers moved their tongue around the mouth and expectorated saliva for 5 minutes. Volumes were measured, flow rates determined and samples stored in liquid nitrogen. TAOC was determined by enhanced chemiluminescence (Chapple et al. Ann Clin Biochem 34:412-421, 1997) and reported as Trolox equivalents (Teq). Results: Mean saliva flow rates at baseline, immediately and 10 minutes after smoking (mean range: 0.80-0.93ml/min) were non-significantly higher in light smokers compared to heavy smokers and comparable to those of non-smokers (mean range: 0.87-0.91ml/min; Brock et al. J Clin Perio 31:515-521, 2004). Flow rates were not affected by smoking at these early times but were increased at 60 minutes compared to baseline (p=0.08 and p=0.015 for light and heavy smokers respectively). There were no significant differences in TAOC concentration or delivery (uM Teq/min) after smoking. Mean TAOC concentrations were non-significantly higher in heavy smokers (mean range: 302-335uM Teq) compared to light smokers (mean range: 258-290uM Teq) at all times and higher than levels reported in non smokers (mean range: 248-250uM Teq). Conclusion: These data show that smoking 1 cigarette has little immediate effect on saliva flow and TAOC content/delivery. Differences in flow rate and TAOC content between heavy, light and non-smokers may reflect the development of compensatory physiological process in chronic smokers.