Figure 1.
Smoking duration in smoker and ex-smoker participants.
Footnote: PD+, participants with a declared periodontal disease diagnosis present;
PD−, participants without a declared periodontal disease diagnosis.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.