Dear, Best regards
In typing an email to a teacher or in general, what would be used to open the email (Dear XXXX,) and also to close the email (Best regards, sincerely, etc) Thank you!
Email is considered much more informal than even a short note or letter. It is commonplace to just use the persons name or to not even include a salutation in the correspondence. However, courtesy and politeness are never inappropriate. As a sign of respect for your teacher's position I would include the "Dear" salutation and the "Sincerely" closing. And do not worry the the "Dear" sounds overly familiar. It's recognized as a formal means for addressing even a stranger and is no more personal than closing with "besos" is in Spanish.