Our Team

Dr. Zak Dental Care has been serving the community of Southern California since 1994.

At Dr. Zak Dental Care, we are dedicated to continuously teaming up with the most qualified dental professionals and specialists.

Meet our Team

Our staff is extremely well-trained and skillful, and we are committed to providing enthusiastic and positive service to all our patients. All our team members are registered assistants, and the staff has had many years of experience in providing patients with superior care.

Dr_Ilya_ZakDr. Ilya Zak, DDS

Dr. Ilya Zak attended USC Dental School, graduating in 1990. He was one of only eight unique students to complete the ADAPT program, an accelerated 6-year dental program that allows one to complete both undergraduate and graduate requirements. After graduation, he completed TMJ/Pain Management residency at White Memorial Hospital and became a qualified medical examiner for TMJ dysfunction in California. He is also a part-time clinical instructor at his alma mater, USC Dental School, and he practices in Simi Valley, Valencia, Agoura Hills, and Long Beach since 1994.  Dr. Zak ensures that the dental care that is provided at Zak Dental offices is wholistic, comprehensive, and enhances patients’ overall wellness.

Dr. Howard Kopel, DDS

Dr. Howard Kopel, DDS, attended USC School of Dentistry and has been working in the field for more than 3 decades. He has received excellent training in every dental field, and he has received numerous awards for excellence in oral cancer diagnosis. He utilizes his keen understanding of comprehensive dental care to ensure that his treatment plans are optimized for the ultimate goal of enhancing patients’ wellness.  In his free time, Dr. Kopel loves to race fast cars, play tennis, and spend time with his family.

Dr. Shirashi, DDS, our teamDr. Ronald Shiraishi, DDS

Dr. Shiraishi was born and raised in California, and attended UCLA for undergrad and Washington University for dental school. He has been working in our Downey office for more than 25 years, and he has treated generations of patients. Dr. Shiraishi has almost 3 decades of experience and is committed to improving his patients’ health. In his free time, he enjoys being outdoors and fishing.

Dr. Olga Karnakova, DDS

Dr. Karnakova graduated from the Moscow Medical Stomatological Institute in 1991.  She worked for many years in Moscow before moving to the United States where she has worked for over 18 years as a general Dentist and part time instructor for the Duggan Study Institute.  Dr. Karnakova’s approach to patient care is wholistic to ensure a strong and positive link between oral health and patient wellness.

Dr. Olga Karnakova is fluent in English and Russian languages.

Dr. Charles Chung, DDS, our teamDr. Charles Chung, DDS

Dr. Charles Chung graduated from Loma Linda University’s School of Dentistry in 1999. While there, he went on many volunteer missions in southern California and South America that involved dental work and inner-city volunteering. He is a member of the American Dental Association and California Dental Association.  His work is always precise and performed calmly, making him very popular with patients.

Dr. Nadia Abazarnia, DDS, our teamDr. Nadia Abazarnia, DDS

Dr. Nadia is a Graduate of the Carlo Davila University of Bucharest in 1993. She is Fluent in English, Farsi, and Romanian. Dr Nadia has been practicing in California for over 14 years. She brings her wealth of knowledge in implantology to every patient that she sees and treats.  Dr. Nadia is an avid believer in developing treatment plans that are designed to enhance patients’ oral health and optimize their overall wellness.

Dr. William Olson, DDS, our teamDr. William Olson, DDS

Dr. William Olson attended Loma Linda University, graduating in 1987. His entire family is in the medical field which is what made him become a dentist. His passion is doing restorative and cosmetic work, and seeing his patients smile after the work is done. It brings him a huge satisfaction when he helps patients reach their ultimate goal when it comes to their smile. One fun fact about him is that he likes to go hiking, skiing and loves dogs.

Dr. Roshanak Momen, DDS, our teamDr. Roshi, DDS

Dr. Roshanak Momen (Roshi) received her degree in 2016 from Loma Linda University, School of Dentistry. She also got an award for being a Teacher’s Assistant in Restorative Dentistry. She has her DDS degree from Azad University in 2009 as well. Dr. Roshi speaks English and Farsi and is committed to improving his patients’ health.

Dr. Paul Bayat, DDS, our teamDr. Paul Bayat, DDS

Dr. Paul Bayat graduated from USC Dental School. He has  more than 15 years of experience in the dental field. Dr. Paul has been treatment planning and treating more than 50,000 patients. Dr. Paul’s emphasis on the patients’ overall well being and his ability to prioritize treatment plans to any budget has allowed his to enhance the oral health of nearly all patients that he sees irrespective of their financial challenges.

Dr. Tuyet Mai PhanDr. Tuyet Mai Phan

Dr. Mai Phan initially received her Bachelor’s degree in Electrical Engineering from the University of California, Irvine.  Then, Dr. Mai Phan went on to obtain her DDS from USC. She is a gentle individual by nature, and strives to provide great services and care to her patients. Dr. Mai Phan tries to complete her work in a fashion she truly stands behind. Her expertise as a dentist is laser assisted periodontal management, hygiene cosmetic fillings, veneers, inlay/onlays, teeth whitening. In her spare time, D. Mai enjoys books, traveling and spending time with her family.


Dr. Nicu Schrager

Expertise: Removable Prosthetics (dentures, partials)

Dr. Schrager completed his Doctor of Dental Surgery at the University of Southern California USC Los Angeles. He has been at Temecula Dental Group since the opening in 1990. His artistic eye for detail and precision help provide specialty care for patients needing dentures and partials – implant supported or not. When asked why he chose dentistry as his profession he immediately responded that for him, dentistry is not simply a profession but a passion for him to be able to offer the best dental treatment possible and fulfill the needs of the patient.

Dr. Kristen Miller, Our teamDr. Kristen Miller, Orthodontist

Dr. Kristen Miller is graduated from UCLA with general dental education and UCSF with her orthodontist training. She graduated the class as top 5% students. She  was also the Vice President of her dental school class. Dr. Miller participated in the UCSF mobile clinic. She is fluent in Spanish.