What Is The Correct Dosage For BV Medication?

hi doctor, i am 30 years old and have bv and i must use flagyl for 2 times a day ( 500mg*2) but also i will have an operation from my wisdom tooth and my dentist told i can also use flagyl to prevent an infection but she recommends to use the pill 3 times a day instead of 2, what must i do now? if i use flagyl 3 times a day (400*3)instead of 2(500*2) , is it gonna help my bv or i must take it 2 times a day for bacterial vaginitis ?