(714) 784-5568



Dr. Tim Stegelvik, DDS

Dr. Tim Stegelvik has provided comprehensive dental care to residents of Orange County for over 30 years.  Dr. Stegelvik received his BS Degree from the University of California, Irvine and was a member of the schools first graduating class.  He then started his dental practice after graduating from the University of California San Francisco School of Dentistry in 1974.

Dr. Stegelvik is committed to excellence in dentistry and well-known for educating his patients and involving them in the diagnosis and treatment planning process. He is very conservative, honest, and appreciates the artistic side of dentistry.  He is a member of the California Dental Association, American Dental Association, and Orange County Dental Society.

In his free time, Dr. "Tim" and his wife travel all over the world playing famous Four & Five Star golf courses...Kingsbarn in Scotland, being his favorite.  His family are avid College Football fans and have attended multiple championship games. He enjoys reading and visiting bookstores where he can find wonderful old history books.  Dr. Stegelvik is also a former pilot, owning his own plane, so whenever he can he and his family hop on a plane and fly somewhere.


Dr. Don Nguyen, DDS

Dr. Don Nguyen was born in Ames, Iowa and spent the majority of his childhood growing up and traveling overseas. After returning to the States, he settled in the Southern California area, graduating from the University of California, Irvine with a BS Degree in Biological Science and earning his DDS Degree from the University Of Southern California School Of Dentistry.

Dr. Nguyen practices all phases of general dentistry, with an emphasis on Cosmetic, Fixed, Endodontic, and Restorative dentistry. He dedicates himself to providing the highest quality of comprehensive dental care, along with exceptional patient-service, by practicing both traditional and contemporary techniques. Along with continuing his postgraduate education and advancing his understanding of dentistry, he is also an active member of the American Dental Association, California Dental Association, and Orange County Dental Society.

Aside from dentistry, Dr. 'Don' as his patients know him, enjoys traveling abroad and has visited over 25 countries in six different continents. Dr. Don believes it is important to continually give back, while at USC he participated in the schools first dental externship to Vietnam, providing pediatric dental care to underserved children.  Dr. Don also enjoys college football (USC Trojans), golf, photography, and spending his free time with friends and family.

Dr. Ryan Lange, DDS

Dr. Ryan Lange is a native Californian who grew up in Riverside. After receiving a B.S. degree in Health Science from California Baptist University, he headed east in order to earn his Doctorate at Boston University's School of Dental Medicine.

Dr. Lange’s approach towards dentistry is very patient-centric. His comprehensive, yet conservative approach leaves his patients feeling confident about their treatment plans. And his honest caring manner provides them with the knowledge they need to make informed decisions, as well as give them an understanding of what to expect moving forward.

Dr. Lange’s extensive training and experience in CEREC® Technology, allows him to provide his patients with crowns and veneers in a single visit. His other disciplines in dentistry including Invisalign® braces, in office bleaching, endodontics, and restorative dentistry. Dr. Lange is an active member of the California Dental Association, American Dental Association, and the Orange County Dental Society.

Outside of spending time with his family and friends, Dr. Lange enjoys tinkering on cars, and using his carpentry skills to build furniture for his home.

Our MacArthur Staff



Buffy - Registered Dental Assistant

I’ve been a Registered Dental Assistant for 25 years and worked with Dr. Stegelvik for the last 12 years. I absolutely love the team/family I work with. I have two wonderful kids; my son works for a local high school and my daughter is just starting college. My recent ventures have included traveling to Costa Rica and enjoying time with my husband.


Nancy P. - RDH

I’m Nancy. I’ve been a hygienist for Dr. Stegelvik for almost 24 years. I have a gentle, caring touch. I treat my patients how I would like to be treated.


Dawn F. - Back Office Assistant

Hi, I’m Dawn. I am living proof that it’s never too late to pursue a new career. I began working part time at MacArthur Dental Arts in 2015, while still working as a Starbucks Barista. I retired after 13 years at Starbucks and I’m a full-time team member at MacArthur Dental Arts. I was at one time operating charter yachts as a USCG Licensed 100 ton Master. I am training to become a dental assistant and I couldn’t have found a better place to learn. I have a son Michael, a rescue pup Mitzee, and a little red convertible roadster.


Breanna A. - Treatment Coordinator

I’m Breanna and I have been with MacArthur Dental Arts for several years. Three of those years were spent working with and assisting the doctors. That experience has greatly benefitted me in my new position as Treatment Coordinator. I love traveling, mountain biking, watching the latest Super Hero Movie, and spending time with my friends and family. I love what I do and am so grateful to be working with all of the wonderful Doctors and Staff here at MacArthur Dental Arts.


Sommer R. - RDH

Hello, I am Sommer. I have been in the dental field for 14 years, first as a dental assistant and now as a hygienist. I feel so lucky to be part of this great dental family! I love my job and I am passionate about teeth and taking care of my patients. I spend my spare time watching my son play hockey and going to the beach with my husband.


Erika - RDH

Hello! I’m Erika! I have been in the dental field for 16 years. I started off as a Registered Dental Assistant before I became a hygienist. I am currently working on my Masters Degree and cannot wait to finish. I am looking forward to getting married this fall. I have worked with Dr. Stegelvik for several years and I’m very pleased to be part of the MacArthur Dental Arts team.


Tim - Insurance Specialist

Tim our Insurance specialist has been with the practice for over 10 years. Besides handling all of your insurance needs, he enjoys reading mystery thrillers, playing poker, and traveling.


Debi - RDH

I’ve been with our office for ten years. I still look forward to coming to work every day. Originally from Illinois, I grew up here in Orange County. Recently engaged, I now divide my time residing in Diamond Bar and the San Diego mountains.

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