1 year old teeth care!?

What have your doctors/dentists said about teeth care for a one year old (16 months now)?

Our dentist said to start using fluoride tooth paste (size of a grain of rice) once a day since we do not have fluoride in our water. But since starting that I have noticed a small white spot appear on his teeth (from too much fluoride!?).

Ugh I am constantly stressing/worrying about what I should/shouldn’t be doing! #momlife

Let me know what you were told and what works for you! ESP if you’ve had other children 😜

Thanks!