The first time a tooth fell out of his mouth, he was in elementary school, playing with other children: Bakugo and his little group. Izuku was already about six or seven years old. As always, they pushed him and wanted to leave him behind. But the insistent child followed them wherever they went.
It was in one of those shoves that he felt something fall on his tongue.
"OH!" The little green haired boy could only get up, feeling a little pain in his mouth and the taste of something metallic. He spat into her hand a small white piece stained with blood. A tooth. "E-Eh ?! What happened?!"
"Hey, Deku! What do you want no-? EWWWW!" The blond boy shouted, after starting to laugh in a mocking mode. "YOU'RE SO USELESS YOU CAN'T EVEN KEEP YOUR TEETH IN PLACE!"
Deku got up dizzy, blood on his mouth. He went to the classroom as fast as he could.
And then he was already with his mother at the dentist.
"Do I have a quirk to change my teeth?" asked the little boy, hoping that this had been some manifestation of his quirk.
"No... In fact, it's a show of your... Situation as a quirkless person" Said the dentist looking at the child with a raised eyebrow. He could only sigh and show him some X-rays they did on the kid that day before. "Look. Your current teeth will be replaced by stronger ones as soon as the ones you have all fall out. They will only be replaced once so, keep your dental hygiene and take more care of them". The dentist told him, shaking his hair trying to cheer him up.
That was the first baby tooth to fall out, and obviously it wouldn't be the last. But he never expected it to take so long for them to fall.
It took a few years for almost all of his teeth to fall out and be replaced by permanent teeth.
He was already at the UA, everything was calm while he attended some classes, and it was time to have the typical training sessions. That day, they were gonna do combat exercises in one of the school gyms.
"Midoriya and Bakugo are going to train together on that mat, Uraraka and Iida on that other, Yaoyorozu and Hagakure on that other..." Aizawa sensei said, while he waited for everyone to get into their positions. "Remember that this is hand-to-hand training without quirk..." He took out a bag of juice and put it in his mouth.
"Ha this is gonna be easy! Ready nerd?" Bakugo saw his opponent, and instantly grimaced.
Izuku had a finger in his mouth, distracted... Did he had a loose tooth? He moved it a little with his finger ... Yes, he was definitely about to fall.
"HEY! DON'T IGNORE ME WHILE I TALK TO YOU, DAMN DEKU!" The one with messy hair yelled.
"AH! Sorry Kacchan!" The one with curly hair was about to get into a fighting position, when the blonde one, who didn't even gave him time to settle in, already had his fist on the freckled kid's face.
Izuku fell down onto the mat, and could only spit.
"K-Kacchan! It's the third tooth you make me throw!" He demanded annoyed. He got up, rubbing his cheeks... "I'll be right back..."
"Hey! Deku! Be quick! Don't let me waiting!"
He walked towards the entrance still with the tooth in his hand and with a trail of blood trickling from his mouth to his chin. He passed next to the mat where Todoroki and Sero were doing their training.
"Midoriya-kun? What happened to you?" Todoroki asked after seeing the kid with blood on his mouth.
"Oh! It's nothing" He wiped his mouth with his hand, though a little blood was still dripping. "Kacchan made me threw a tooth at me, that's all", he said calmly, to which Sero and Todoroki blinked in surprise.
"BAKUGO DID WHAT?!" Sero yelled. "AIZAWA SENSEI, BAKUGO MADE MIDORIYA THROW A TOOTH!" He exclaimed alarmed, and so everyone instantly put down their mats and approached the freckled one to see what was right.
"Are you okay Deku-Kun?! Doesn't it hurt!?" Ochako asked, very scared.
"Bakugo! Pulling your teeth at others is not very masculine of you!"
"Guys I'm fine! It had to fall anyway! It's from the baby teeth set! It's going to be replaced anyway!" He said trying to calm them all. The blood was no longer coming out of the hole left by the tooth which relaxed him a bit.
"Did I hear what you said well?" Aizawa asked behind everyone. "The teeth are not replaced, Midoriya."
... Oh... People with quirk only have one set of teeth... now he remembered...
"W-Well.. A-At least mine get re-replaced?..." He said doubtfully.
"... Go to recovery Girl, I'm sure that doesn't happen, but whatever you say problem child..."
The boy took a few steps back and ran away.
"... Bakugo you're grounded."
"WHAT?! WHY?! IT'S NOT MY FAULT THAT THAT IDIOT'S TEETH LOSE AND GROWS AGAIN!"
That afternoon...
Midoriya was walking through the campu,s using his cell phone. The hole in his mouth was uncomfortable, but it was something he had passed through before so he didn't mind.
"Midoriya!" He heard a boy scream right behind him, he turned to find Denki. "Feelin' better?"
"Uh, hi Kaminari-kun! Yeah, I'm better" He smiled showing his teeth with everything and the hole.
"Eek!" Kaminari froze when he saw the small hole in the boy's mouth. "Is it serious that it will grow back? Aren't you tricking us all?" Said the boy raising his eyebrow and with a grimace of disgust.
"Yeah! Don't worry. This has happened to me since I was six or seven years old". Deku said, scratching the back of his neck and smiling nervously. "Besides, it's not that bad. The tooth fairy will give me money for my baby teeth.
"... Fairy? money?" The blonde's eyes shone a little.
Oh no. For children with quirk, since their teeth do not fall out, never get gifts from the tooth fairy...
"Who gives you money for your teeth? What do you mean?"
"Uh ... Eh ... Well ..." Miraculously, his cell phone rang instantly. "Uh, I have to answer! Goodbye Denki!" He said and instantly ran away.
"Hey! Midoriya don't lea-and he's gone. - Denki rolled his eyes. Tooth fairy?
Izuku could only sigh when he was already away. Well... At least that was the only thing that happened... He answered his cell phone and went back home.
The next day...
He didn't expected to see Kaminari and Kirishima fighting inside the classroom.
"PULL MY TEETH TO MAKE MONEY!" Denki shouted, who was looking straight at Kirishima. Kirishima, who had a hardened fist, gave another blow to the blonde's face, who already had quite a few bruises.
The other classmates who were there (only Bakugo, Iida, Yaoyorozu, and Todoroki), were either watching them or trying to stop them.
"Guys stop hitting each other! We are in a prestigious school!" Iida yelled stopping Kirishima from behind.
"But Denki told me to pull his teeth to make some money and we want to try it!"
"And do you think it's worth pulling teeth for money?!" Iida scolded the two fools. Yaoyorozu could only sigh, stopping Denki with one hand.
Midoriya stared at them for a few seconds and approached them a little nervous.
"Uh... what's happening now?"
"Midoriya! Isn't it true that when your teeth fall out someone gives you money?!" Denki said instantly as a lot of blood came out of his nose, but with intact teeth.
"Denki told me that you said that could happen, and we wanted to try! Did that witch gave you money for your tooth yesterday or not?!" Kirishima asked with encouragement.
Midoriya couldn't do anything other than ... Start laughing. A Lot. Almost crying of the laughter.
"What-what funny guys! You can't pull your teeth between yourselves! And they won't bring you anything because it only works with baby teeth!" He said still laughing, with tears in his eyes.
"I told you, couple of morons!" Shouted Bakugo, who was just watching the show. He was laughing since a few moments actually.
"... So I broke my nose for nothing? And what are the milk teeth you talk about so much about?!" Momo let go Denki, who went to claim Midoriya, who was still laughing on the floor.
After calming down, Deku was able to explain.
"Most people who have the same teeth throughout their lives from the moment they are born and come out, until the moment they die. But there are people who still have the physiognomy of the people before the quirks, who have an initial set of teeth called milk teeth, which are replaced over time by other teeth that are now permanent," he said calmly, pointing to his mouth. "Like this" He opened his mouth, showing a tiny, tiny, little white tip sticking out of the gum. "This the second tooth that will come out" He said, finishing the explanation.
"Now that I notice, Midoriya, the lack of your anterior tooth makes you pronounce the "s" strangely" Said Iida who also heard the explanation of the curly haired boy.
"I-I guess so"
"So does that mean you were born with theet?" Momo asked curiously.
"No, they're just called baby teeth because they got replaced by "adult" teeth after some time"
"I have seen that All Might suddenly spits blood, and when you dropped it you also spit blood. Are those things related?"
"Todoroki-kun, no"
"Are you sure you're not All Might's secret lovechild?"
"TODOROKI-KUN!"
"Yeah yeah yeah YEAH, we already heard the Todotheories but but BUT, then what does that have to do with that they give you money for your teeth and that thing with the Witch that buys your teeth?" Denki asked, looking badly at the boy, holding an ice pack in his hand and pressing it against his cheeks.
"Oh! That... Well, my mother told me that when a tooth falls out, we must leave it under the pillow so that the tooth fairy, a magical being that collected children's teeth before the quirks, would give me us some gifts. The fairy tooth always gives me money. But it only works with the first set, as the second is permanent. And well... You guys can't be visited by the tooth fairy because it's as if you've always had the second set" He said trying to downplay the situation by shrugging his shoulders.
"... Aw..." Denki's disappointment was heard instantly.
"oh... Oh no... Bro, Sorry for... Hitting you in the face" Kirishima said looking at the boy with the lightning bolt in his hair.
"Don't worry, It's ok..."
Midoriya could only smile with some nervousness.
"OI, DEKU!" Bakugo shouted from behind. "I knocked your tooth out, you owe me half of what that fairy shithead gave you this time!"
"WHAT?! NO!"