YOU SAID:

I have many loose teeth in my mouth

INTO JAPANESE

私は私の口の中にたくさんの緩い歯があります

BACK INTO ENGLISH

I have a lot of loose teeth in my mouth

INTO JAPANESE

私の口の中にはたくさんの歯が緩い

BACK INTO ENGLISH

Many teeth are loose in my mouth

INTO JAPANESE

多くの歯が私の口の中で緩んでいます

BACK INTO ENGLISH

Many teeth are loose in my mouth