About Us

Welcome to Brea Ranch Dentistry

Drs. Karen and Johnny Koo are your trusted husband-and-wife dental team, dedicated to providing comfortable, quality care tailored to your unique dental needs. The Koos met and began dating after their freshman year at Loma Linda University School of Dentistry and were married shortly after their graduation in 2003. Along with their two young daughters, they reside in North Orange County, and have operated Brea Ranch Dentistry since July of 2012. Though they only recently took over the practice, they are pleased with the positive reception and extremely touched by the support and kind words from their patients and staff. Their goal is to provide you with a positive dental experience, a healthy smile, and a trusting relationship with their friendly, caring team.

Johnny Koo, DDS

Johnny began his path to dentistry by earning a degree in psychobiology, then continuing on with his four-year dental training at Loma Linda University School of Dentistry. As the associate dentist for a group practice, he has devoted the last decade to furthering his dental continuing education and advancing his clinical skills. He and his wife Karen have been serving the local community since the Summer of 2012 when they became the new owners of Brea Ranch Dentistry.

Dedicated to the pursuit of advanced training, Dr. Koo works to stay abreast of the latest techniques and technologies in dentistry. He has continued to pursue advanced education in areas important to his patients, such as cosmetic and implant dentistry.

Dr. Koo is passionate about helping his patients achieve excellent oral health and creating a quality patient experience. From offering alternative treatment options to helping each patient come to a decision they are comfortable with, his desire is for his patients to be happy with the treatment they receive.

In his spare time, Johnny enjoys an occasional round of golf or tennis and spending time with his family. His greatest joys are his 8 and 10 year old daughters, who have a blast playing games and outdoor activities with their hands-on dad. He is happily married to his best friend and fellow colleague Karen.

Karen Koo, DDS

Karen completed her undergraduate studies in the Napa Valley and graduated with a B.S. in Biology. She then earned her D.D.S. at Loma Linda University School of Dentistry and was the recipient of the Academic Excellence Gold Award for her performance on Parts I and II of the National Boards. Throughout her dental career, she has participated in various educational and training opportunities, including short term orthodontics. Dr. Koo is a certified provider for 6 Month Smiles short-term orthodontics, and she herself is also a 6 Month Smiles clear braces patient!

Before coming to Brea Ranch Dentistry, Karen enjoyed working as an associate dentist in private practice and was fond of working with all age groups, including small children. Her gentle, caring nature tends to put patients at ease. It is Dr. Koo’s ongoing mission to create a comfortable dental environment for her patients and to provide them with personalized, compassionate and quality dental care.

When not at the office, Karen is a busy mom to her high-spirited little daughters. She values quality time with her family and enjoys volunteering her time and service at her daughters’ school and at her church.