Cigarette Smoking and Oral Microbiota

* INCLUSION CRITERIA This study will recruit a convenience sample of 50 volunteers (25 current smokers with at least 5 years of smoking history, 25 never smokers). Current smokers are defined as individuals who have smoked more than 100 cigarettes in their lifetime and have smoked 5 or more cigarettes in the last 24 hours. Recent use of other tobacco products (pipe, cigar, snuff, cigarillos, and chewing tobacco) is an overall exclusion, but use in the remote past (\> 6 month ago) is acceptable in smokers. Never smokers are defined as individuals who have never smoked cigarettes nor used any other tobacco products including pipe, cigar, snuff, cigarillos, or chewing tobacco. The ethnic mix of the clinic is roughly 50% Caucasians and 50% African- Americans with a small number of unspecified or other racial groups. The median age is about 50 and the gender mix consists of an equal number of men and women. We therefore will select smokers and frequency match to non-smokers based on ethnicity (White, African-American), gender (male, female), and age (above or below the median, estimated to be 50). EXCLUSION CRITERIA We will exclude pregnant women and other racial groups because they may represent very small numbers and thus be difficult to match. Hormonal changes associated with pregnancy and unique cultural habits associated with specific ethnic groups could be associated with highly unique or variable microbiome patterns, and therefore reduce the power to detect differences associated with smoking which is our primary goal. We will also exclude subjects with antibiotic usage in the last three months and subjects with previous diagnosed major periodontal disease or cancer because they might be potential confounders.