When you are "dedicated to" something it means the same thing as being "devoted to" it. For example, you can be very dedicated to your job but a priest would be very devoted to his church. It is just that the terms are not used in exactly the same way in other instances. For example, you might say "I will dedicate this song to you" but you would not say "I will devote this song to you." Devote/devoted is used mainly to describe a more powerful version of dedicate/dedicated. Example: She is devoted to her children but he is a dedicated teacher.