If you are going to say this to your teacher is "Gracias mi profesor" or "profesora" for a female teacher. Maestro o maestra is also used but less formal (but still appropriate) If you want to say that you have learnt something thanks to your teacher then you say "Gracias a mi maestro".. I have learnt this and that and so on...

`'Thank you my teacher' means 'Gracias profesor'. I've learnt that 'Thanks to my teacher' means 'Gracias a mi profesor'.

yeah they're right... it is "gracias profesor"

"thank you my teacher" is literally "gracias profesor", just as Sonia already told you. A sample sentence (well, dialogue) would be: - EdwardWu: Profesor, ¿qué nota saqué en el examen? -Profesor: Un 0! Hiciste un examen muy malo EdwardWu, pero como me regalaste un maletín lleno de billetes te pondré un 10 -EdwardWu: Wow! GRACIAS PROFESOR.

"Gracias a mi profesor"