noun
dental plaque
Refers to the soft, sticky film that forms on teeth. Often used in everyday conversation; the more formal medical term is 歯垢 (しこう).
See also: 歯垢
歯糞がたまると虫歯になりやすい。
If dental plaque builds up, you're more likely to get cavities.
歯医者で歯糞を取ってもらった。
I had the dental plaque removed at the dentist.
歯垢 is the formal medical term for dental plaque, while 歯糞 is a colloquial, somewhat crude expression.
Compound of 歯 (tooth) and 糞 (excrement, waste), literally 'tooth waste'. The colloquial nature reflects the earthy metaphor.