1The act of brushing your teeth; can also refer to the daily routine or time spent on it. Used as 「歯磨きをする」 or directly as a suru-verb 「歯磨きする」. This is by far the more common everyday meaning.
寝る前と起きてからの歯磨きは欠かさないようにしている。
I make sure never to skip brushing my teeth before bed and after waking up.
子どもが嫌がるので、歯磨きの時間は毎晩ちょっとした戦いだ。
My kid really hates it, so brushing time is a bit of a battle every evening.
歯医者さんに、歯磨きのしかたが間違っていると指摘された。
The dentist pointed out that my brushing technique was wrong.
食後すぐより、三十分くらい経ってから歯磨きをしたほうがいいらしい。
Apparently it's better to brush your teeth about thirty minutes after eating rather than right away.
2A dentifrice — toothpaste, tooth powder, or gel used for brushing teeth. Note: in everyday speech most Japanese speakers say 歯磨き粉 (はみがきこ) for 「toothpaste」; using 歯磨き alone in this sense sounds somewhat old-fashioned or formal and is most often seen in product names, pharmacy shelves, and advertising (e.g., シュミテクト歯磨き).
薬局で歯科医おすすめの歯磨きを買った。
I bought some toothpaste recommended by my dentist at the pharmacy.
このメーカーの歯磨きは、知覚過敏向けに作られている。
This brand's toothpaste is formulated for sensitive teeth.