A Better Life Starts with a Beautiful Smile

Proudly serving North SLO County for over 30 years.

Welcome to Sienella Thomaszadeh, DDS

At Sienella Thomaszadeh, DDS, we believe that optimal dental health is an integral component of good overall physical and mental health. Through continuing education, advanced procedure training, state-of-the-art materials and techniques, technological advances and by teaming with a well established team of specialists in our community, we work to provide our patients a pathway to beautiful, durable and healthy smiles. We believe that by practicing preventive dentistry and providing patient education and encouragement, we can take a conservative approach to providing dental care.

Dentist clinic equipments

Meet The Doctor

Dr. Thomaszadeh started her career in dentistry over 20 years ago as a dental assistant. During her time chairside, caring for patients and educating them she realized her passion for dentistry was much more than just a career choice. Every day she eagerly went to work enthusiastic to help transform people's lives through their smiles. She enjoyed being part of a healthcare team that worked to better families lives through improved oral health. Becoming a dentist was a dream Dr. Thomaszadeh set her mind to accomplish. She earned her Bachelor’s in Biology at the University of California, Los Angeles. She continued to dental school on the east coast to earn her doctorate at New York University, College of Dentistry in 2012. While she enjoys the technical aspects of dentistry, the part of dentistry that gives her career purpose is the real connections she has with her patients. She spent a year of her time in New York providing dental care in a clinic serving survivors of torture and war traumas and their family members. Her most cherished and fondest memories of service in the field of dentistry are still, and will likely forever be, the time she spent in that clinic. She is passionate about a life of service and has spent time as a volunteer in multiple organizations in SLO as well. Don't be shy, Dr. Thomaszadeh loves chatting with patients about her favorite recipes and local hiking spots. When she's not transforming smiles, she enjoys relaxing and spending time with friends and family.

Dr. Sienella Thomaszadeh

Request an Appointment

Please complete this form, and a member of our team will contact you to confirm an appointment time.

(805) 461-1772

Complete Care on Your Schedule

Bringing Life to Your Smile
Experienced Staff

Our team is experienced, and will provide a seamless and comfortable treatment for our patients.

Advanced Treatment

Our extensive service offerings ensure all of our patients receive the care they deserve without compromises.

Modern Equipment ​

We are constantly investing in new, innovative equipment to provide the best care possible.

Dentistry for Today’s Lifestyle

We Have All Your Dental Needs Covered.
Dental X-Rays​
Exams & Cleanings
Cosmetic Dentistry
Periodontal Disease​
Root Canals​
Teeth Whitening​
Braces & Implants​

(805) 461-1772

Happy Stories

Let our patients speak for themselves!
Staff was fast and friendly, office was clean and tastefully decorated. Dr.Thomaszadeh was very thorough, one of the most thorough oral exams I’ve had, and easy to talk with. Working in the medical field myself these are all attributes of a well organized and run office. I’m looking forward to continuing my dental care with Dr Thomaszadeh’s team.
Caitlin P.
Had a filling fall out and they got me in the next day after I called. No waiting at all at office. Went right in and Dr T took care of it right away. Was as good as new in 25 min. Absolutely top notch care by Dr T and her entire staff. Could not be happier.😁
Patrick M.
Dr. Thomaszadeh and her staff are the best! We had been with Dr. Romanelli for almost 10 years before he retired and we couldn't have lucked out any more with her taking over his practice. We've been treated by her and her professional, amazing staff for many years now, with all levels of dental needs, and they never disappoint. So grateful for Dr. T, Beth Ann, Marissa, and the rest of her team!
Kathy M.
Dr.Thomaszadeh is amazing, patient, and gentle ! I used to see her at another office, and was thrilled to find her again. All the staff is wonderful. From the front office Marissa is kind and helpful. The dental hygienist is very gentle as well. Also, all the staff and assistants are sweet and gentle too. If you have any anxiety about the dentist, then this is the place to come. They will make you feel very comfortable and welcome.
Cat C.
Absolutely the best dentist I've ever been to!! Dr. Thomaszadeh is very nice, personable, knowledgeable, and skilled. Her office staff is kind and helpful. The dental hygienists in this office are also the best I've ever encountered. They're very detailed in their work and highly skilled at cleaning mouths with braces/orthodontic appliances as well. 10/10 would recommend over and over again.
Kasha G.



4555 El Camino Real, STE D
Atascadero, CA 93422





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