Dr. Hammes is a native to the Chicago area, having grown up in Mt. Prospect, Illinois. He earned his Bachelors of Science in Mechanical Engineering from the University of Illinois at Urbana-Champaign and graduated from the University of Illinois at Chicago’s College of Dentistry in 2008. Upon graduation, Dr. Hammes began his dental career with the U.S. Navy, completing a one-year Advanced Education in General Dentistry residency at Great Lakes Naval Health Center. From there, Dr. Hammes served as the dental officer aboard two ships, the USS GERMANTOWN (LSD-42), and the USS HARPERS FERRY (LSD-49), homeported in San Diego, California. He then served as division officer of Oral Diagnosis at Recruit Training Command Great Lakes.

From 2013-2014, Dr. Hammes completed a one-year Fellowship in Implant Dentistry at the Southern Illinois University School of Dental Medicine in Alton, Illinois. Dr. Hammes is dedicated to excellent patient care in a comfortable environment, oral health, and staying up to date in the advances in dentistry through continuing education.

Dr. Hammes enjoys sports, volunteering, the outdoors, staying in shape, travel, and pulling for teams to break 100-plus-year championship droughts.

Peter Hammes

Dr. Tien earned her Doctor of Medicine in Dentistry degree from the Southern Illinois University School of Dental Medicine.  Having experienced first-hand the importance of oral health and the barriers to access to dental care, she decided to help others with significant dental needs and a lack of resources.  She fulfills this passion working full-time at a Federally Qualified Health Center.  We are grateful Dr. Tien brings her expertise and skills to Washington Dental Care on a part-time basis. 

In her free-time, she enjoys traveling to new places and experiencing different cultures and food.  Additionally, Dr. Tien enjoys volunteering to clean and groom animals at local shelters in her spare time.

Sarah Tien

Gaja has been working in the health care field for over 15 years with experience in orthopedics, gynecology and gastroenterology. She is a very knowledgeable and dedicated professional who's commited to exceptional quality work. Gaja works meticulously with Dr. Hammes as well as our patients and their families to make certain that all oral health needs are met in a timely, efficient, and caring manner. Gaja plays an essential role in the success of the practice.

In her spare time she enjoys spending time with her wonderful husband, two sons, cooking, decorating and traveling.


Tabitha has been in the dental field since 2008. She has worked as a clinical assistant on cases ranging from fillings to implant surgeries. Tabitha is an extremely skilled and organized team member, focused on comfortable and efficient patient care. She is a people person who loves working with and learning about our patients. She enjoys dentistry because there is the constant opportunity to learn and grow.

In her time away from the office, Tabitha loves being a mother to a very active little boy. She especially likes to take him outdoors, doing everything from playing in the snow to bike riding.