A character's dental state will often be used to show their personality in fiction. A young child will often have missing teeth, typically the upper front ones, if they are supposed to be sweet and energetic or innocent. It may also be used with children who have had their baby teeth replaced to showcase someone who is troublesome or reckless, to the point where they knocked out or otherwise lost their adult teeth. A gap between teeth (not due to a lack of teeth) may be used to make a character look more innocent or youthful.
Compare to Youthful Freckles, another design trait used to showcase a character's youth.
Truth in Television: Most kids lose their baby teeth between six and eight years, and probably won't have orthodontic work done to repair more permanent gaps until the early teens. And of course, anybody can get a tooth knocked out if they're not careful.
- Subverted with Aiko from Goodnight Punpun. She is introduced as a little girl with missing front teeth. Punpun is instantly attracted to her and conjures up an image of her as a cute Manic Pixie Dream Girl. Aiko in reality is a Broken Bird, and it just gets worse as the manga continues. This is played darkly late into the series, where the now-adult Aiko gets a tooth knocked out which makes her look similar to how she did when introduced. Within fifteen chapters she's Driven to Suicide.
- One Piece: Sabo in his younger years was shown with a missing tooth gap. While it might've been a naturally detaching milk tooth, the fact that he prefers to live in the streets may also contribute to that.
- Child!Fuka is shown to be missing a tooth at the beginning of ViVid Strike! (it's implied that it got knocked out in a fight with some bullies). By the time the story proper starts, the gap is gone.
- Josuke Higashikata from JoJo's Bizarre Adventure has a a distinct gap between his front top teeth which accentuate's his "innocent amnesiac" somewhat childish naivete to the world. One of his Fan Nicknames is "Gappy". The reason for the gap isn't merely orthodontic.
- Heintz's Daddy's Girl daughter in Magnetic Rose is depicted with a gap in her teeth in flashbacks. It turns out they're flashbacks because Emily died at that age.
- In the 2016 version of Runaways, eleven-year-old Molly Hayes is depicted as having a prominent tooth gap. This annoyed some fans, as this was supposed to be the Earth-616 version of Molly, whose dad was a dentist.
- Ellie from Up had teeth in this fashion in her childhood flashbacks. She was a fiery, upbeat tomboy.
- Darla from Cats Don't Dance has a gap in her teeth but subverts the "innocent" cliche, being a strong example of Kids Are Cruel.
- Hiro Hamada from Big Hero 6 has a gap on his front teeth◊. He is the youngest major character but subverts it as he is a fourteen year old Teen Genius.
- 10-year-old Ben from Song of the Sea sports a tooth gap.
- Eleven year old Riley from Inside Out has a tooth gap.
- Kid Hero Hiccup from How to Train Your Dragon has a gap between his front teeth which he retains even after growing up in the Time Skip between the first film and the second.
- White from Tekkonkinkreet sport a tooth gap to accentuate his innocent demeanor.
- Miguel from Coco has a gap on the left side of his upper row of teeth.
- In Tales Of A Fourth Grade Nothing from Judy Blume's Fudge book series, Fudge, who at that point was only two years old, loses his two top front teeth when he falls off a jungle gym, pretending that he was a bird. His older brother Peter secretly calls him Fang, even though he never says it out loud because his mother doesn't like the nickname.
- In an inversion of this trope, Peter remarks that the missing teeth make Fudge look like "a very small first grader", since Fudge is much younger than the usual age for losing teeth
- Lodo from Yo-Kai Watch is a young looking youkai who is childish and likes milk. He has a tooth gap. It could also be related to his hygiene, as the youkai he is based on looks like a dirty, old man and gives people bad luck.
- In Tetrobot And Co, Maya has missing teeth in the photographs from her childhood.
- The goofy and childish Rabbids from Raving Rabbids all have buck-teeth with gaps in them.
- Finn from Adventure Time is a Kid Hero with only a few teeth. According to Word of God this isn't stylistic. Finn is missing several teeth because he is an Idiot Hero who bites things like rocks.
- Meng from Avatar: The Last Airbender, the Adorkable young girl from the episode "The Fortuneteller", has a missing front tooth.
- The titular protagonist of Clarence is missing two front teeth. He is an elementary school-aged boy. Clarence is Fun Personified and a Wide-Eyed Idealist.
- Inverted with Edd from Ed, Edd n Eddy; he's the most intelligent and mature of the trio, despite having a rather large gap between his two front teeth. Of course, this gets exaggerated when Eddy takes Double D's story off the rails in "Once Upon an Ed". His teeth become ridiculously large and the gap gets even wider.
- Parody Sue Chloe from The Fairly OddParents! has a gap in her teeth to emphasize her cutesy look.
- Harvey Street Kids: Audrey's redesign gives her a tooth gap to go with her new tomboyish personality.
- The Loud House: Lana and Lola both have gaps where their front teeth should be. Leif and Lexx, their gender-bent counterparts from "One of the Boys", have their front teeth, but are missing a tooth on either end of them.
- In Phineas and Ferb - Save Summer, there is a scene where Candace watches an old VHS she made when she was 5 years old. We discover that she had a gap in her teeth making her adorable.
- SpongeBob SquarePants: Spongebob has a noticeable gap between his buck teeth. He's a childish and innocent Manchild.
- Steven Universe:
- Inverted with Peedee, who is a cynical but Adorably Precocious Child.
- A young Steven has one as seen in "We Are the Crystal Gems", here◊. It, combined with his Blush Stickers, makes him look even cuter and more innocent than usual.
- Buck has a tooth gap when briefly seen in a flashback in "Three Gems and a Baby", set fourteen years in the past.
- Donatello has a tooth gap in Teenage Mutant Ninja Turtles (2012). He's the most adorkable of the brothers.
- Cody and Mike in the Total Drama series have this, likely to show their Adorkable and vulnerable side.
- Beast Boy has a gap in his teeth in the second season of Young Justice. He's the youngest member of the team and is energetic.