Effect of cigarette smoking on the transition dynamics in experimental gingivitis

This paper reports the findings of an experimental gingivitis study conducted in smokers and non-smokers. 33 volunteers were examined and underwent prophylaxis during a period of 4 weeks. 28 subjects who showed a plaque index less than 0.20 on all prophylaxis occasions were permitted to continue in the study. Subjects then had their gingival status recorded, had their teeth polished and were requested to abstain from all oral hygiene measures for the following 21 days. After 5 days, 10 days and 21 days, plaque and gingival status were recorded using the criteria of the plaque index and gingival index. After the examination on day 21, the teeth were polished and oral hygiene was re-instituted. Following 2 weeks of supervised oral hygiene, recordings of plaque and gingival status were performed. At the initial examination, there was no difference between the clinical assessment of plaque and gingival status in smokers and non-smokers. Similar amounts of plaque accumulated in the 2 groups during the period of no oral hygiene, but smokers exhibited less gingival inflammation assessed clinically than non-smokers. This difference occurred as a result of an apparently lowered incidence rate and a markedly higher recovery rate in smokers compared to non-smokers. These findings may indicate that smokers for reasons yet unknown have a reduced capacity to mount and maintain an effective defense reaction to a given plaque challenge.