I had a filling put back in at the dentist the other day.
I had a filling that came loose in one of my molars, so I went to the dentist to have it reset.
ーI had a filling put back in at the dentist the other day.
「先日歯医者で詰め物を詰め直してもらった」
to have a filling put back in で「詰め物を詰め直してもらう」
dentist で「歯医者」
the other day で「先日」
ーI had a filling that came loose in one of my molars, so I went to the dentist to have it reset.
「奥歯の一本から詰め物が取れたので、歯医者に行って詰め直してもらった」
to come loose で「緩む・抜ける」
molar で「奥歯」
to reset で「はめ直す」
ご参考まで！
カナダ 
