Translation guide
A tooth that has decay, typically due to caries. In Japanese, the most common term is 虫歯 (mushiba), literally 'bug tooth'. Other terms exist for specific contexts.
The most common, everyday way to refer to a tooth with a cavity or decay.
The standard word for a decayed tooth or cavity. Used in both casual and formal contexts.
A more technical or medical term for a decayed tooth, often used in dental contexts.
う歯の予防にはフッ素が有効です。
Fluoride is effective for preventing decayed teeth.
A highly technical term for a carious tooth, rarely used outside dental literature.
齲蝕歯の治療法について研究している。
Researching treatment methods for carious teeth.
When you want to describe the condition of a tooth, rather than name the tooth itself.
Literally 'a tooth that has become a decayed tooth'. A natural way to say 'a decayed tooth' in context.
虫歯になった歯を抜いてもらった。
I had my decayed tooth pulled out.
Using the verb むしばむ (to decay, to rot). Slightly more descriptive.
むしばんだ歯を放置すると危険です。
It's dangerous to leave a decayed tooth untreated.
Unless you are in a highly technical dental context, 虫歯 (mushiba) is the word you want. It covers both the cavity and the tooth itself.