John Hill, Supervisor of Military Programs for Colonial Williamsburg, lays this one to rest. “I have heard many reenactors note the need for two opposing teeth as part of their musket-firing interpretations. Such a requirement isn’t mentioned in any of the drill manuals of the period. I don’t recall seeing anything requiring two opposing teeth in any of the recruitment documents or officers’ guides. It seems possible that a toothless soldier could have partially torn the musket cartridge in advance and then “gummed” it open or maybe even torn it open by hand. Tearing the cartridge in advance is seen as a safety hazard today, but I doubt if it would have been in the 18th century.” Perhaps this started as a joke in the reenactment community and was taken seriously by some.
Do Civil War sites hear this one too?
Another (minor) consideration: As far as dental health was concerned, things were not as bad as people are led to believe. There was much less sugar in the diet in the 17th and 18th centuries, largely because sugar was a luxury item and very expensive. Less sugar = fewer cavities = fewer rotten teeth.