Meet Our Staff

image of the doctor Michael J. Collura

Michael J. Collura


Michael J. Collura, D.M.D.

Dr. Collura, a highly skilled and dedicated clinical endodontist, founded the office of Big Apple Endodontics (formerly Michael J Collura DMD PC) in 2003. He earned his DMD degree from the prestigious School of Dental Medicine, University of Pennsylvania in 1993. After completing a one-year General Practice Residency at North Shore University Hospital of Long Island, Dr. Collura pursued specialty training in endodontics back at his alma mater, University of Pennsylvania, in 1996.

Armed with advanced education and expertise in endodontics, Dr. Collura confidently ventured into private practice in the NYC and Long Island areas, where he continued to provide exceptional endodontic care and an unwavering commitment to the oral health of the communities for more than 27 years.

image of the doctor Chia-Yi Chen

Chia-Yi Chen

D.D.S., Diplomate, American Board of Endodontics.

Chia-Yi Chen, D.D.S., Diplomate, American Board of Endodontics.

Dr. Chen joined Big Apple Endodontics (formerly Michael J Collura DMD PC) as a partner of the practice in 2007. She was born and raised in Taiwan, where she also had her dental school education and her two-year general dentistry residency training. Dr. Chen then pursued endodontic specialty training at the College of Dental Medicine, Columbia University in 2000. After completing the postgraduate endodontic program, Dr. Chen joined the full-time endodontic faculty at Columbia from 2002-2007. She also earned her American DDS degree at Columbia University.

After that, Dr. Chen traded her academic career for a clinical endodontist practice serving in the NYC and Long Island areas. Even then, she continued to teach part-time at Columbia as an Assistant Clinical Professor of Dentistry from 2007 to the present. Driven by an unwavering commitment to excellence, Dr. Chen became a Diplomate of the American Board of Endodontics since 2010. For any professional communication or inquiries with Dr. Chen, please reach out at

image of the doctor Sara Hamzeinejad

Sara Hamzeinejad

D.M.D., M.S.

Sara Hamzeinejad, D.M.D., M.S.

Dr. Sara Hamzei is an endodontist associate at Big Apple Endodontics. She is dedicated to providing individualized and quality endodontic care to her patients in New York City.

Dr. Hamzei grew up in Southern California, where she completed her bachelor’s and master’s degrees in biology with a focus on Stem Cell Research at UCSD. Through volunteering and later managing the UCSD Free-Dental Clinics for the underserved community of San Diego, she found her passion in dentistry. Dr. Hamzei received her Doctor of Dental Medicine degree from University of Pennsylvania with honors in Community Oral Health. Additionally, she received comprehensive training in complex and hospital-based dentistry by completing her General Practice Residency at St. Barnabas Hospital in New York. After practicing as a general dentist in Los Angeles, California, Dr. Hamzei returned to New York City to pursue her specialty training in endodontics at Columbia University.

Dr. Hamzei is an active member of the American Association of Endodontics and the American Dental Association. She is committed to providing compassionate, high-quality care to her patients. In her free time, she enjoys painting, reading, attending live music events, dining at incredible restaurants in New York City and beyond, outdoor sports and activities, as well as traveling the world.

image of the doctor Kiara Arevalo

Kiara Arevalo

Patient Coordinator

Kiara Arevalo, Patient Coordinator

Meet Kiara, the warm and welcoming face of our dental clinic, and the cornerstone of our administrative team. With a passion for helping others and extensive experience in reception and customer service roles, Kiara brings a wealth of knowledge and a friendly, approachable demeanor to our practice. Beyond her exceptional organizational skills, Kiara’s true strength lies in her ability to connect with people. She greets each patient with a warm smile and genuine empathy, making them feel comfortable and valued. Her commitment to excellent customer service extends to assisting patients with scheduling, insurance inquiries, and any questions or concerns they may have. In her spare time, Kiara enjoys spending quality time with her family and giving back to the community through volunteer work. Her dedication to making a positive impact is not limited to the workplace but extends to the world around her.
image of the doctor Alison Crespo

Alison Crespo

Treatment Coordinator

Alison Crespo, Treatment Coordinator

Meet Alison, the person willing to go above and beyond to make sure you leave the office satisfied with the treatments. She is available for our patients after hours to answer any questions they may still have to help in any way. Alison loves her team and her patients.

Alison is constantly learning new things and, no matter how much she thinks she knows, she always values room for growth. Being open and adaptable in an ever-changing field is something that excites Alison, knowing that each day is an opportunity.

image of the doctor Lydia Mejias

Lydia Mejias

Lead Assistant

Lydia Mejias, Lead Assistant

Lydia loves that her career gives her the chance to make a significant difference in the lives of her patients. She has been with Big Apple Endo for over 15 years and has been part of a cultural change to a practice driven by quality delivery. At Big Apple Endo, Lydia is key to our patient satisfaction and team professional growth.

To Lydia, being part of a team means being there for one another, building each other up and lending a helping hand whenever it is needed.

image of the doctor Salma Valdez

Salma Valdez

Dental Assistant

Salma Valdez, Dental Assistant

Salma Valdez is our dental assistant and has been with us for the past two years. Known for her unwavering dedication and hard work, Salma is deeply committed to providing exceptional care to our patients. Her attentive and caring nature ensures that every patient feels comfortable and supported throughout their dental visit.

With Salma's expertise and genuine passion for dentistry, she plays a crucial role in delivering high-quality service and making a positive impact on our practice.


121 East 60th Street, Suite 4A,
New York, NY 10022

Office Hours

MON9:00 am - 4:00 pm

TUE7:00 am - 4:00 pm

WED - FRI9:00 am - 4:00 pm

SAT - SUNClosed