Dear patient and parents, we will start calling patients to schedule appointments on Monday May 18.


Welcome To Liu Orthodontics!




Beautiful , Confident Smile

Dr. Terry R. Wallen, DDS, MS


  • Two-phase orthodontic treatment is a very specialized process that intervenes early problems and prevents future issues. This involves tooth straightening, jaw growth modification, facial appearance, and speech.


In general, younger patients with crossbites, server crowding, excessive overbites can often lead to two-phase treatment. Early intervention can prevent further damage of teeth or gum tissue and maximize the opportunity to accomplish the ideal healthy, functional, aesthetic result that will remain stable throughout your life.


The disadvantage of waiting for complete eruption of permanent teeth and having only one phase of treatment for someone with a jaw discrepancy is facing the possibility of a compromised result that may not be stable. For example, growth of the jaw cannot be modified when the ideal timing of treatment is already passed.


Children sometimes exhibit early signs of jaw problems as they grow and develop. Jaw discrepancy due to the jaw growing too much or not enough can be recognized at an early age.

The goal of first phase treatment is to develop the jaw size in order to accommodate all the permanent teeth and establish a harmony jaw relationship. With a high growing potential in children, orthodontic appliances can redirect the growth of the upper and lower jaws. This early correction may prevent surgical procedures to align the upper and lower jaws. Permanent tooth extraction may be avoided with space management or expansion of the jaw for children with moderate crowding.


Once phase one of treatment is finished, braces will be removed. Patients usually wear retainers until all the permanent teeth erupt, during this time tooth eruption will be monitored. Dr. Liu or Dr. Wallen will see them usually every 6 months and supervise retainer wear or determine if removal of certain primary (baby) teeth is necessary during this break period.


The second phase is initiated after all permanent teeth have erupted for an average of 12-24 months. In the second phase, tooth position and detailing will be finalized using braces or clear aligners. A healthy, beautiful smile is created with balance of facial structures.


Retainers must be worn after this phase to ensure you retain your beautiful smile. At Liu Orthodontics, we usually use an upper clear retainer and lower fixed retainer with or without a clear retainer. It is very important for you to wear your retainers as instructed. Otherwise, teeth will move back where they were. You can click link to learn how retainers work.

Education and professional background

My passion in orthodontics has driven me to receiving many years of education and pursing professional development.  Being born and raised in Taiwan, I attended Taipei Medical University, where I earned my DDS and Master’s degree of Orthodontics in 1999 and 2003. I received my PhD degree from Baylor College of Dentistry, Dallas, Texas in 2008. Shortly before graduation, I was appointed as Assistant Professor of Orthodontics in the Indiana University School of Dentistry. Meanwhile, I completed my second Master’s degree in Dentistry and Orthodontic certificate from the Indiana University School of Dentistry.  Later in 2015, I was promoted to tenured Associated Professor and became a certified orthodontist by American Board of Orthodontists.

I love practicing, researching, and teaching orthodontics. There are more 40 scientific papers I published in American Journal of Orthodontics and Dentofacial Orthopedics, European Journal of Orthodontics, Angle orthodontists, and Bone.  I am also a coauthor of “Basic and Applied Bone Biology”.  In 2010, I was honored the Beni Solow Award because my article was selected the best paper of European Journal of Orthodontics. After serving as Director of Orthodontic Fellowship Program for 3 years, my enthusiasm of teaching was well recognized and honored the Outstanding Faculty Award in 2013.

Outside the office

  • Outside my professional life, I am also a loving husband and father of 2 boys. We love to travel and explore the outdoors. We enjoy clamming, camping, and hiking in state parks. My older son, Ryan, plays soccer all year round. You might run into us in the soccer fields of Washington Cup. My little boy, Jaylen, loves art. You might see us doing some craft projects together at school festival nights.

Professional Honor and Awards

Resident’s Choice- Outstanding Orthodontic Faculty Award

Indiana University School of Dentistry 2013


Beni Solow Award

European Orthodontic Society 2011


Albert P. Westfall Memorial Teaching Fellowship Award

American Association of Orthodontists 2010


Orthodontic Faculty Development Award American

Association of Orthodontists Foundation 2010


Faculty First Award

American Association of Orthodontists 2009


Outstanding Research Award

Congress of Taiwan Association of Orthodontics 2003


Best Graduate Resident

Taipei Medical University 2003

Dr. Terry R. Wallen, DDS, MS

Dr. Terry Wallen, the founder of our office, is one of the pioneer orthodontists in the northwest. He established our practice in 1974 and has treated more than ten thousand patients.

Academics and Accomplishments

  • Terry Wallen completed undergraduate studies at Seattle University.
  • He received his dental education at the University of Washington.
  • He received numerous awards for academic and clinical excellence.
  • Dr. Wallen was inducted into the Omicron Kappa Upsilon honor fraternity which is reserved for those graduating in the top 10% of each class.
  • At the University of Kentucky, he received his specialty training in orthodontics.


  • Wallen was a part-time Clinical Professor of Orthodontics at the University of Washington
  • A certified member of the American Board of Orthodontists.
  • A recipient of the Edward Hatton Award from the International Association of Dental Research
  • An Internationally-known lecturer and widely published author in the specialty of orthodontics
  • An editorial consultant to an orthodontic journal

118 SW 330th St #200, Federal Way, WA 98023

TEL:(253)838 - 0765

FAX:(253)838 - 3416

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