19th century sign, advertising teeth pulling
A 22nd century dental scan
Teeth (singular tooth) were bony structures found in the mouths of most species. They aided in chewing food and the speaking of their languages. They were typically cared for by the medical practice of dentistry.
The process of growing teeth was called teething. Human babies, when teething, often interrupted the sleep of those caring for them. While caring for the mimetic simbiot Sim in 2153, Doctor Phlox was at a loss to understand how Human adults endured the REM cycle interruptions their children caused. (ENT: "Similitude")
On Earth, most whales didn't have teeth. Instead, they had a soft gum-like tissue, called baleen, that strained vast amounts of tiny shrimp for food. (Star Trek IV: The Voyage Home)
Following the Horta's attack on Schmitter in 2267, only fragments of bone and teeth were found. (TOS: "The Devil in the Dark")
According to Greek mythology, teeth from a dragon slain in war, if spread over a battlefield, would produce one warrior per tooth, each of which would then continue fighting. In 2376, this myth was conveyed to Captain Janeway of USS Voyager by her first officer, Chakotay, in the presence of Gedrin, a member of the Vaadwaur species. He was relating the dragon's teeth and their hidden potential to a long-dormant cache of Vaadwaur ships Gedrin had led them to. (VOY: "Dragon's Teeth")
In the Ferengi and Klingon cultures, teeth were sharpened with a tooth sharpener. (ENT: "Broken Bow"; DS9: "Little Green Men")
The Cardassian Bureau of Identification collected a tooth (the first molar) from all citizens of the Cardassian Union at the age of ten. It also collected the molars of non-citizens caught up in the Cardassian legal system. Miles O'Brien experienced this firsthand in 2370 when mistakenly believed to have worked for the Maquis. (DS9: "Tribunal")
During the 19th century on Earth, barbers also served as dentists, and were often known for pulling teeth. (TOS: "Spectre of the Gun"; ENT: "North Star")
In 2293, shortly before he was assassinated, Klingon Chancellor Gorkon used a large tooth from an unknown lifeform as a cane. (Star Trek VI: The Undiscovered Country)
Mullibok told Kira Nerys, during supper, about how he had started as a farmer on the Bajoran moon Jerrado and how he grinded up mineralized clays with his teeth to enrich the soil. (DS9: "Progress")
Odo had no teeth, as he informed Makbar, the Chief Archon at Miles O'Brien's trial on Cardassia in December of 2370, when fulfilling the role of O'Brien's nestor during the proceedings. (DS9: "Tribunal")
Captain Benjamin Sisko referred to Klingon teeth as "fangs," and mentioned how he missed them after having a Klingon disguise he had worn removed from him. Odo disagreed, saying that he, for one, wouldn't miss the fangs at all. (DS9: "Apocalypse Rising")
During Tuvok's promotion to lieutenant commander in 2374, Harry Kim told a humorous anecdote about a joke of him. He noted that you could hear Tuvok grinding his teeth from across the bridge. (VOY: "Revulsion")
While getting angry, the psychopatic isomorph Dejaren described eating to B'Elanna Torres as "Grinding up bits of plants and animals with your teeth. Secreting saliva to force it down your esophagus into a pit of digestive acids." (VOY: "Revulsion")
When Commander Chakotay mentioned that diplomacy was not part of the Hirogen lifestyle, Captain Janeway responded that they have to convince the approaching Hirogen or the Voyager will show its teeth like any other cornered animal. (VOY: "Prey")