Should i clean my teeth before or after breakfast?

Depends: I would strongly lean to brushing before eating. But if you are going to brush after the meal wait at least 30min after eating to allow for the acidity level to balance.

How about both!: You could consider doing both. Brush your teeth thoroughly before breakfast to remove the protein and bacteria that gather on them overnight. The reduced number of bacteria means less reaction to any sugar you may eat at breakfast. After breakfast, rinse vigorously with water to remove any food debris, then rinse and gargle with a good mouthwash. Cleaned twice and ready for the day.

After : I would clean your teeth after meals to remove food particles from your teeth.

< 25 min after meals: The 25 minute period after finishing a meal is the most prone your teeth will be to cavity causing effects. Brushing after meals greatly reduces this risk. This also coincides with the ada recommendation of cutting down on in-between-meal snacks. Essentially, you will reduce the number of times in a day that cavities can attack your teeth. And don't forget to floss!