/jp/ - Otaku Culture

Sometimes people are born with really crooked teeth, or they develop crookedly as they grow up due to having a mouth too small for their teeth or whatever. These cases are mostly genetic. If a person has enough money, they might have them straightened, crowned, or removed and implants implanted to replace them. Bad looking teeth don't always arise from failure to brush. At age 23, and not coming from poverty (caries are strongly correlated with low socioeconomic level) I think it is highly unlikely Nanase has lost a tooth merely from not brushing her teeth. And looking at the rest of her nice, neat teeth I'd say that, however minor, she's had some cosmetic dentistry done and the gap was a part of it (for example, removal before implants, or making room for other teeth).

Now gasp in horror at Himura's old teeth.