Early 16th-century dentistry was a barbaric practice that specialised in pulling teeth, but hadn't perfected a method of replacing them. Attempts had been made as early as 700BC, when Etruscans put ivory dentures on a gold bridge, and rudimentary wrought iron dentures that had been nailed into the jaw of a Roman Gaul were recently discovered in rural France.
Odontologically speaking, the breakthrough came in early 18th-century Paris, when surgeon Pierre Fauchard, who coined the term dentist and is generally regarded as the father of the profession, produced a kind of spring-loaded set of dentures. They were supposed to let the wearer smile with confidence, but frequently jumped out of their mouths instead.
Until then, it had been a case of make-do. Even Elizabeth I had padded out her gums with cloth to give the appearance - at least from a distance - of a full set of teeth. For people with more money than teeth, ivory or porcelain dentures became available in the late 18th century, but they were fixed with silk thread and hardly functioned as incisors. In polite society, toothless guests at dinner parties would use a masticator to break down food, and apples were off the menu.
The mass casualties of the Battle of Waterloo in 1815 had a particularly grisly by-product. Waterloo teeth, salvaged from the dead, became popular with unscrupulous denture makers, being much more realistic and longer lasting than the cattle teeth which had been commonly used, even by American president George Washington, who wore a metal frame fitted with cow's teeth. He wasn't alone among world leaders - Winston Churchill had his dentures adapted to play down his lisp, and always carried a spare set in case he had a falling-out before a major speech.
Nowadays, dental implants can do away with the need for fixatives and beakers of fizzing water by the bedside. Nothing really can replace lost teeth, but for those a few short of a full set of 32, dentures fill the gap.