Can mouthwash, dentures, or chewing tobacco affect a breath test?

Mouthwash and some breath sprays contain alcohol, and using either shortly before a test can put alcohol in the mouth that has nothing to do with what's in the blood.

Dentures, partials, and dental work operate differently. They can trap fluid, and trapped fluid can hold alcohol past the point where the mouth would otherwise have cleared. Chewing tobacco does something similar.

Here's the part worth knowing: the observation period is the safeguard against all of it, and the rule directs the operator to reasonably ensure nothing has gone in the mouth. Whether the officer actually asked is a question with an answer — it's on the body cam, or its absence is.

An officer who ran a proper observation period and asked the right questions has closed the door. One who didn't has left something open, and whether that matters depends on the rest of the record.