KINGSPORT — Kingsport City Schools Dobyns-Bennett High School math teacher Theresa Fuller has been designated as a National Board Certified Teacher. Fuller is one of 20 Tennessee educators who are part of a group of 5,470 new National Board Certified Teachers (NBCT) from around the nation. “We know that teachers are the biggest factor in the success of our students, and it is an honor to celebrate educators who are helping their students grow, while serving as an example of what it means to be a lifelong learner,” said Candice McQueen, Tennessee Education Commissioner.