MARK D. HOROWITZ, DDS For over 35 years, generations of patients return to Washington Square Dental Group because of our commitment to personal, high quality, and compassionate dental care. Two Fifth Avenue, Suite 4 NEW YORK , New York, NY 10011 New York MARK D. HOROWITZ, DDS This dental office is the best! Everyone is so welcoming and friendly. The care they provide is excellent, absolutely top-notch. I always feel like my teeth and oral health in general are in the best of hands.