A familiar side effect of marijuana smoking is increased appetite, often for sweet foods. It is doubtful that the marijuana smokers immediately rush to brush their teeth after eating “munchies.” If they smoke multiple times throughout a day, they may be constantly nibbling on sweets, leaving food lodged between teeth and gums, a fairly direct cause of gum disease.

Linda Walsh
Santa Cruz, Calif.

One result of such incessant munching would be plaque buildup. The researchers accounted for differences in plaque, as well as overall dental care, among the participants. These and other things being equal, pot smokers still had more periodontitis than people who didn’t smoke the herb. Periodontitis starts out as gingivitis, marked by red, bleeding gums. When this inflammation results in the gums separating from the teeth and jawbone, that’s periodontitis, which typically is irreversible. Gums receding from teeth make them look longer. This is often due to periodontitis in old age. Hence the term “long in the tooth.” —Nathan Seppa