Dr. Ottosen graduated from The University of Washington School of Dentistry in 1994 and The University of Washington Endodontic Specialty Training in 1996. His research was in NiTi rotary instruments. He opened his first practice in 1996 in Wenatchee, WA.

Dr. Ottosen enjoys teaching his fellow dentists about Endodontics. He has taught for the University of Washington continuing education department. He provides Endodontic continuing education to several Washington study clubs and dental societies.

Dr. Ottosen is a member of The American Dental Association, The American Association of Endodontists and the Washington State Dental Association.

Dr. Ottosen is the founder and president of MicroEndo.