Welcome to Our Practice


Welcome! The dental professionals at Prospect Dental Care are pleased to welcome you to our practice. We want all our patients to be informed decision makers and fully understand any health issues you face. That's why we've developed a website loaded with valuable information about dental problems and treatments. We encourage you to visit this site whenever you have concern about your teeth.

Our website also provides you with background about our staff, office hours, insurance policies, appointment procedures, directions to our office in and other useful information. We know how hectic life can be and are committed to making our practice convenient and accessible. We want you to feel confident that you're working with doctors and other professionals who are qualified, experienced and caring.

Please take a few moments to look through this site to get a better feel for Prospect Dental Care's capabilities and services. We also invite you to email or call our office to request an appointment or ask any questions. Thank you.

Meet Our Doctors

Learn Who We Are

  • Koushyar Keyhan,

    Dr. Keyhan has over 20 years of experience in clinical dentistry. He graduated in 1998 from McGill University in Montreal, Canada and subsequently completed a 2 year General Practice Residency (GPR) in Brooklyn, New York. He then moved to San Jose, California and entered into private practice, while being a part-time clinical instructor at UCSF School of Dentistry.

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  • Siamak Madani,

    Dr. Siamak Madani is a specialist in the fields of periodontics and dental implants. He completed both his dental school training and specialty program at the University of Pennsylvania in Philadelphia, PA.

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  • Sheila Nguyen, DDS, MS
    Board-Certified, Pediatric Dentist

    Dr. Sheila Nguyen has been part of the multi-specialty team at Prospect Dental Care since 2017. She is a Bay Area native. Growing up, she was a student-athlete, receiving her high school diploma from Saint Francis High School and her Bachelor of Science degree in Human Biology from the University of California San Diego (UCSD). 

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  • Alan Chee,

    Dr. Chee is a second generation dentist from San Francisco. After completing his undergraduate studies at UCLA, he earned his DDS at the University of the Pacific and completed a 1-year general practice residency at the Jesse Brown VA in Chicago, IL.

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  • Tiffany Bui,

    Bio Coming Soon...

  • Betsy Duell,

    Dr. Duell received her B.A. in psychology from University of California, Los Angeles, her D.D.S. from New York University, NY and her Pediatric Dental Specialty Residency from University of Southern California / Children’s Hospital of Los Angeles.

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What Our Patients Say About Us

    I would prefer never having to go to the dentist but when I have to I insist on seeing Dr. Keyhan and his helpful staff!  Dr. Keyhan is very detailed in his work and takes the time to explain the procedures and options carefully.  You will immediately benefit from his passion for dentistry and years of experience.  This type of genuine patient care is definitely becoming increasingly rare these days!

    Mr. N. A.

    Dr. Keyhan is a very knowledgeable and pleasant.  In every visit you feel confident that you are in great hands, that he is in complete control of the work and is making the right recommendations to you.  As an engineer I pay attention to details and admire those who do so as well.  Dr. Keyhan’s attention to details in his work is very commendable.  I would recommend Dr. Keyhan to anyone looking for a great dentist and would be more than happy to discuss it in more details. 

    Mr. M. B.

    I’ve personally known Dr. Keyhan for several decades and he has been my dentist for the past 10 years.  I am always impressed by the amount of attention and time he devotes to each individual patient.  His knowledge, expertise and experience are highly admirable and shine when he explains treatment thoroughly and professionally.  I am confident that Dr. Keyhan’s passion for density is one of the key elements of his success.

    Dr. D. A.

    I feel asleep while he was working on my teeth....
    And he is not about getting the most $$ out of you. I went to him because a previous dentist had told me I needed some 25 feelings and 3 root canals, and 7 crowns. Well, turns out i needed 9 feelings, with no root canals, and no crowns.

    Definitely recommend this guy.

    C. J.

Our Location

Find us on the map

Hours of Operation

Our Regular Schedule


8:30 am-5:30 pm


8:30 am-5:30 pm


8:30 am-5:30 pm


8:30 am-5:30 pm


8:30 am-5:30 pm