All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is permissible for you to pray in that dental clinic and you are not sinful by not going to the mosque, as the congregational prayer is valid everywhere, because the Prophet said: “The earth has been made for me a mosque.” [Al-Bukhari and Muslim]
It is permissible for your manager to prevent you from going to the mosque as long as this harms the work, and you have to pray in congregation where you are, and there is no sin on you.
Your prayers are valid, sufficient, and you have fulfilled the obligation, Allah willing.
Allah knows best.