About us

Our Team

Our Mission

At ONE ENDO, our mission is simple: to create fear-free endodontic care. We strive to empower our patients to take steps towards achieving their healthiest smile. Getting your dental health back on track should be something you’re proud of, not afraid of. We are here to make the process as simple and stress-free as possible. Not only do we want you to feel relaxed at our office, but we also want you to enjoy your time with us. With a friendly team, modern amenities, and comfortable care, we are making this possible.

Meet Your Doctors

Nick Mastroianni, DDS

As a native New Yorker, Dr. Mastroianni was born and raised in Northern Westchester County. He attended North Salem Central School District where he excelled both academically and athletically alongside his good friend and now business partner, Dr. Dean Saccomanno. Dr. Mastroianni earned his Bachelor’s Degree in Biology from Boston College and later proceeded to the University of Medicine and Dentistry of New Jersey (UMDNJ) where he received a Master’s Degree in Biomedical Sciences.

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Nick Mastroianni, DDS

As a native New Yorker, Dr. Mastroianni was born and raised in Northern Westchester County. He attended North Salem Central School District where he excelled both academically and athletically alongside his good friend and now business partner, Dr. Dean Saccomanno. Dr. Mastroianni earned his Bachelor’s Degree in Biology from Boston College and later proceeded to the University of Medicine and Dentistry of New Jersey (UMDNJ) where he received a Master’s Degree in Biomedical Sciences.


During his time at Boston College and UMDNJ, Dr. Mastroianni not only developed a passion for science, but more specifically for healthcare and dentistry; especially after working alongside several dentists who he considers mentors. His passion continued to mature as he earned a Doctor of Dental Surgery (D.D.S.) from Stony Brook School of Dental Medicine, where he witnessed the profound physical, mental, and emotional wellbeing brought forth by a healthy smile. He went on to complete a General Practice Residency at the Veterans Affairs Medical Center in Northport, where he had the honor and privilege of treating the individuals who served our great nation. Dr. Mastroianni returned to Stony Brook School of Dental Medicine to complete his Advanced Education Program in Endodontics, where he trained using the most advanced technology to gather extensive knowledge in surgical and non-surgical Endodontics.


Dr. Mastroianni prides himself on giving back to the local, regional, and national communities as a healthcare provider. He travels across the country participating in Remote Area Medical missions to rural, underserved areas to provide dental care to individuals in need. Patient comfort, patient understanding, and overall patient wellbeing are of utmost importance to Dr. Mastroianni. He values building relationships with his patients beyond the dental chair, getting to know them on a personal level, and making sure their root canal experience is seamless and stress-free.


Outside of the office, Dr. Mastroianni enjoys spending time with his high school sweetheart turned wife, Nicole, his friends, and his family. He also enjoys traveling, physical fitness, and sports, while expanding his horizons with golf and playing guitar. Dr. Mastroianni says he was thrilled with the opportunity to join Dr. Cotter and the team because of the environment and culture they strive to promote. As Dr. Mastroianni puts it, “The philosophy of the practice is genuine and easy to get behind – appreciate, collaborate with, and respect those around you, and the rest will fall into place.”

Dean Saccomanno, DDS

The son of a registered nurse and a local ironworker, Dr. Saccomanno proudly comes from a “blue-collar” household from which he is the very first dentist in his family. When anyone asks Dr. Saccomanno what drew him into dentistry, his answer always stems from his upbringing and the way in which he was taught the basic value of ‘doing right by people.’ Dr. Saccomanno always says he saw a need in the healthcare field; that is, a need for more “down-to-earth” clinicians with the ability to relate to and connect with any patient who walks through the door. As he and his childhood friend, Dr. Mastroianni, like to say, “When someone sits in our chair, it’s someone special. That person may be a mother, father, husband, brother, etcetera. There’s only one way to treat them – as family”. By keeping this idea at heart, these two friends have been given the rare opportunity to deliver a refreshing style of patient-care, one that strongly emphasizes compassion and respect rather than focused solely on the procedures and protocols of dentistry and endodontics.

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Dean Saccomanno, DDS

The son of a registered nurse and a local ironworker, Dr. Saccomanno proudly comes from a “blue-collar” household from which he is the very first dentist in his family. When anyone asks Dr. Saccomanno what drew him into dentistry, his answer always stems from his upbringing and the way in which he was taught the basic value of ‘doing right by people.’ Dr. Saccomanno always says he saw a need in the healthcare field; that is, a need for more “down-to-earth” clinicians with the ability to relate to and connect with any patient who walks through the door. As he and his childhood friend, Dr. Mastroianni, like to say, “When someone sits in our chair, it’s someone special. That person may be a mother, father, husband, brother, etcetera. There’s only one way to treat them – as family”. By keeping this idea at heart, these two friends have been given the rare opportunity to deliver a refreshing style of patient-care, one that strongly emphasizes compassion and respect rather than focused solely on the procedures and protocols of dentistry and endodontics.


In addition to being born and raised in Westchester County, Dr. Saccomanno kept his feet planted in his beloved New York as his education and professional training progressed. He obtained his Bachelor of Science Degree in Chemistry at Iona College in New Rochelle and continued to New York University to complete his pre-doctoral studies. Dr. Saccomanno completed his General Practice Residency at Jacobi Medical Center in the Bronx, whereby he returned to New York University to complete his specialty training in the field of Endodontics. Currently and throughout his residency years, Dr. Saccomanno has treated patients throughout Westchester, the Bronx, and Manhattan. He finds great joy in treating the very communities from which he and his family were brought up and looks forward to building genuine relationships within the town of Greenwich and surrounding neighborhoods.


When not practicing, Dr. Saccomanno truly enjoys his out of office routine, which includes daily physical training, evenings out with his partner, Briana, as well as spending quality time with his brother and mother, Thomas and Donna. Dr. Saccomanno, alongside his mother and late father, Tommy, have spent many active years in the fight against Duchenne Muscular Dystrophy (DMD). These efforts are dedicated to Dr. Saccomanno’s older brother, Thomas, with Donna being the co-founder of an international non-profit organization called Parent Project Muscular Dystrophy (PPMD). It is accurate to say that advocating and raising awareness for Duchenne is embedded in Dr. Saccomanno’s genes as he has had the privilege of learning from his older brother and watching him make great strides over the years. Dr. Saccomanno hopes to translate these ideas of patient advocacy and education to his practice of endodontics.

Michael Cotter, DDS

Dr. Michael Cotter is a Major in the United States Army Reserve, a diplomate of the American Board of Endodontics, and a founding member of the International Academy of Endodontics. He is also an active member of the American Association of Endodontists and the American Dental Association. Dr. Cotter attended St. John's University where he played college football and double majored in communications and biology. He was awarded the Highest GPA award on the football team in senior year, as well as made Second Team All American. Dr. Cotter spent a year returning to his local high school, Mount Saint Michael Academy, where he taught health and biology as well as coached both baseball and football before being accepted to New York University College of Dentistry where he served four years as class president.

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Michael Cotter, DDS

Dr. Michael Cotter is a Major in the United States Army Reserve, a diplomate of the American Board of Endodontics, and a founding member of the International Academy of Endodontics. He is also an active member of the American Association of Endodontists and the American Dental Association. Dr. Cotter attended St. John's University where he played college football and double majored in communications and biology. He was awarded the Highest GPA award on the football team in senior year, as well as made Second Team All American. Dr. Cotter spent a year returning to his local high school, Mount Saint Michael Academy, where he taught health and biology as well as coached both baseball and football before being accepted to New York University College of Dentistry where he served four years as class president.


Following graduation from NYU in 2000, Dr. Cotter attended a one year general practice residency at Montefiore Medical Center. He then returned to NYU for a two year post graduate program in endodontics where he served as chief resident in his second year. In 2003, Dr. Cotter founded Endodontics of Westchester Shore, and in 2014 he founded Greenwich Endodontics. Dr. Cotter is the past president of the Westchester Shore Dental Forum and New Rochelle Dental Forum and is currently a member of the Westchester Shore Dental Forum and the Greenwich Study Club.


Dr. Cotter places value in high quality endodontic care and performs all non surgical and surgical endodontics exclusively under the surgical operating microscope. He strives to provide a stress-free environment for each and every one of his patients. He has published in the Journal of Endodontics and lectured nationally on multiple endodontic topics. He enjoys spending time with his wife, Chrissy; son, Drew; and daughter, Haylee; as well as outdoor physical activities, such as running, swimming, biking, playing golf, and fishing.

Yan Chen, DDS

With roots tracing back to Shenzhen, China, Dr. Chen was raised a city girl in the heart of Manhattan where she was convinced that she would one day become a fashion designer. She attended Clarkstown Central schools in Rockland County, NY where her love for fashion and art remained but her passion for healthcare soon took priority. Dr. Chen completed her undergraduate studies at Binghamton University, where she received her Bachelor of Arts in Economics.

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Yan Chen, DDS

With roots tracing back to Shenzhen, China, Dr. Chen was raised a city girl in the heart of Manhattan where she was convinced that she would one day become a fashion designer. She attended Clarkstown Central schools in Rockland County, NY where her love for fashion and art remained but her passion for healthcare soon took priority. Dr. Chen completed her undergraduate studies at Binghamton University, where she received her Bachelor of Arts in Economics. She went on to receive both her Doctor of Dental Surgery and Endodontic Certificate from New York University College of Dentistry. Additionally, she completed her general practice residency at NYU Langone Brooklyn, a Level 1 Trauma center, where she delivered comprehensive clinical care in various dental disciplines for patients with general and special needs.


During her pre-doctoral training, Dr. Chen was a member of the Omicron Kappa Upsilon National Honors Society and participated in humanitarian outreach programs in Machias, Maine and Pokhara, Nepal, where she provided dental care to underserved populations. During her specialty training, she was selected for the “Honors in Endodontic Teaching” course in which she lectured pre-doctoral and international students on current endodontic evidence-based practices. Dr. Chen is a member of the American Association of Endodontists, the American Dental Association, the New York State Dental Association, and the Ninth District Dental Society. She is a board eligible endodontist and fluent in both English and Mandarin Chinese. Dr. Chen is dedicated to providing the highest quality of care while putting patients at ease and making sure the experience from start to finish is that of a positive one.



Outside of the office, Dr. Chen loves spending time with friends and family, going to the theater, and traveling to new places. She is an avid fan of carbohydrates and is always on the lookout for the best pasta and pizza the city has to offer!

Meet the Team

Elvina

Elvina

Practice Manager

Both clinical and non-clinical operations, Elvina oversees it all. Starting her career with the practice in 2010, Elvina’s responsibilities quickly evolved into a managerial role. Through both her compassion for others and ambition to achieve, Elvina has helped build the practice’s vision for excellence. Her value is immeasurable and our patients find great comfort in her bubbly, positive personality and radiant smile. Elvina cherishes her time spent outside the office with her husband and two daughters, as well as her annual trip to family roots in Montenegro.

Martine

Martine

Clinical Operations Manager

Martine’s unparalleled ability to operate at both the front and back ends of the practice led her to her position of Clinical Operations Manager. Having been with the practice since 2012, Martine’s clinical and administrative versatility is second only to her culinary skills! Outside the office, Martine is likely to be found close to her family and friends, as well as close to a body of water where she loves scuba diving and boating. Her willingness to go the extra mile for the health of our patients has played a crucial role in the overall growth and well-being of the practice.

Gabby

Gabby

Senior Endodontic Assistant

One of the senior endodontic assistants at our practice, Gabby spends half her day laughing and the other half smiling! Not only is Gabby a fantastic chairside assistant, she also takes pride in making sure every patient has a smooth and pain-free experience at our practice. She thoroughly explains everything she does to prepare the patient for treatment with our doctors. After all the years with our practice, Gabby remains highly intrigued by the endodontic specialty and you will constantly find her asking questions to further her knowledge and understanding of the field. Outside the office, Gabby dedicates much of her time to her family and friends, as well as to strengthening community relations through numerous outreach and volunteer efforts.

Kristen

Kristen

Receptionist

One of the most recent additions to our team in 2019, you can expect a warm smile and a great helping hand upon arrival. Kristen obtained her Bachelor of Arts Degree from Hunter College in Manhattan and loves nothing more than her rock music! Kristen’s willingness to grow, learn, and take on new challenges has made her a fantastic addition to our team. Spending the majority of her time in the Mamaroneck location, Kristen plays a vital role in the practice’s daily operations through scheduling and pre-operative preparation of patients.

Margarita

Margarita

Senior Endodontic Assistant

With a kind heart, helping hand, and warm personality, Margarita is one of our senior endodontic assistants who has been with our practice since 2009. She takes pride in her work and always goes above and beyond for all of her patients. Margarita’s years as a specialty assistant show in her ability to be two steps ahead of even the doctor! Margarita’s highly-developed endodontic skillset facilitates the training and mentoring of the practice’s newest clinical staff additions. Margarita is a world-traveler (literally) and spends as much time as she can exploring new places, while simultaneously volunteering her free time to give back to her local and national communities.

Lori

Lori

Patient Coordinator

When the occasional rainy day comes, guaranteed is a little sunshine and a lot of humor from Lori! Lori spends most of her time in our Greenwich location where she oversees the delivery of patient care and acts as a liaison between patients and our endodontic providers. Lori brings exceptional healthcare experience to the practice having worked in the Montefiore Health System. Her enthusiasm keeps a constant flow of positive energy throughout the practice on a daily basis and is guaranteed to keep everyone on their toes!

We Value What Our Patients Say

Great guys and very professional, beautiful office. I actually referred my aunt to them and she couldn’t be happier with the work they did on such short notice! Hope I don’t need a root canal, but if I do, I know where I’m going!
– Kristie Fortuna
Great guys and very professional, beautiful office. I actually referred my aunt to them and she couldn’t be happier with the work they did on such short notice! Hope I don’t need a root canal, but if I do, I know where I’m going!
– Kristie Fortuna
Great guys and very professional, beautiful office. I actually referred my aunt to them and she couldn’t be happier with the work they did on such short notice! Hope I don’t need a root canal, but if I do, I know where I’m going!
– Kristie Fortuna

Judgment-Free Care, Always.

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