Yaeba Teeth

Around 2010, it became a trend in Japan for teen-aged girls and young women to have their dentists to cap their upper canines teeth. Certain pop-idols’ protruding canines were considered adorable and child-like, and it became a fad to emulate their looik. This fad is called yaeba, for "double tooth." 

One fairly recent text to document this trend is Beauty Around the World: A Cultural Encyclopedia by Erin Kenny and Elizabeth Gackstetter Nichols, but the yaeba look has also been the subject of lots of trendpieces in news outlets and magazines.