When the British Expeditionary Force - composed of regular Army men and volunteers before conscription was introduced - set off for France in August 1914, most of the men would have had all or most of their teeth extracted and been fitted with dentures.
This was because the Army sent medical men to deal with injuries and illnesses, and vets to look after the many horses that went to the Front, but not a single dentist. It was only when the commander in the field, Sir John French, got a dose of toothache that anyone thought to remedy this oversight, with 12 dentists being sent in November 1914 to cover the entire Army.
Many soldiers therefore opted to have all their teeth removed before they embarked. This was one way of delaying their arrival, because their gums had to heal before dentures could be fitted.
However, it does sound like a drastic precaution to take, simply because the Army had not thought that soldiers without aching teeth would be more likely to concentrate on the job in hand.
© John Welford