If you would like to work as a dentist in Germany, you would have to apply for a so called approbation.
I do not know if this is possible before you have learned German,
but I found a page which gives you detailed info about the authorities which
would be responsable in your case and how the procedure to apply for an approbation is structured.
You just have to enter your profession and your residence and you will get feedback what the procedure would be like and who you need to contact: