If plaque is not carefully brushed away, it hardens to form a calcified deposit called calculus, or tartar, which may inflame the gums and make them pull away from the tooth.
On September 30, 1846, fellow American dentist William Morton performed a painless tooth extraction on a patient who submitted to ether—the same compound used by Long in 1842.
When the mother hears chirping sounds, she removes the nest covering, sometimes breaking the eggs if the hatchlings have not already done so with their specially provided shell-breaking tooth.
In 1890, Willoughby Miller, an American dentist working in Germany at the University of Berlin, identified the cause of tooth decay, which is a major cause of toothache.
But while studying that local problem, researchers stumbled across a fact of worldwide importance for the prevention of toothache: People raised where drinking water contains inadequate fluoride have more tooth decay.