About Cornerstone Dental Group

Cornerstone Dental Group is a family dentistry practice for patients of all ages, and is based in Westford. Our advanced dental equipment enables us to deliver the highest quality dental care treatment. In addition, we offer cosmetic dentistry services such as checkups, teeth cleaning, crowns, veneers and more.

We provide emergency dental services like bonding, root canals, crowns, and bridges. We aim to create lifelong relationships with our patients and their families, so we can provide our patients with a warm, comfortable and relaxed environment. Experience why our patients think Cornerstone Dental Group is one of the best dentists in Westford, Dr. Papapetros and our staff invite you to schedule an appointment by giving us a call at (978) 692-6012 .

Meet The Doctors


Dr. Stephen Cohen also earned his DMD degree from Tufts University School of Dental Medicine in 1992 where he graduated summa cum laude, and is a member of the dental honors fraternity – Omicron Kappa Upsilon. Dr. Cohen then went on to do a residency at the Boston VA Hospital. Dr. Cohen ran his own dental practice for 16 years in Toronto, Canada with cosmetic dentistry, implant dentistry, endodontics (root canal therapy) and complex restorative dentistry as his main focus. He has maintained dental licensure in both USA and Canada and now works solely in the United States.

Dr. Cohen graduated from Upper Canada College in Toronto for high school, then went on to attend
McGill University in Montreal where he obtained a Bachelor of Science degree with honors in anatomical sciences.

Dr. Cohen is also currently a member of the American Dental Association and the Massachusetts Dental Society, and has prior memberships in the Toronto Academy of Cosmetic Dentistry, Toronto Crown and Bridge Study Club, Ontario and Canadian Dental Associations, and the esteemed Spear Faculty Club in Scottsdale, Arizona.

Dr. Cohen continues to spend countless hours in continuing education across the country while staying happily married to his wife Shari for 24 years. They have 2 university aged children, Melanie and Warren. Dr. Cohen also enjoys local deep sea fishing, and would love to be an avid golfer if he could play better.


Dr. Lam was born and raised in Boston’s South End. He graduated from Boston Latin and the University of Massachusetts’ Commonwealth Honors College of Amherst with a Bachelor of Science in Kinesiology. He would then earn his DMD from Tufts University School of Dental Medicine.

Dr. Lam’s desire to help others who are less fortunate has been apparent in his involvement with Dentists for Humanity and Project Bridge. He has led multiple service trips to Haiti through Dentists for Humanity for three years in addition to volunteering for Project Bridge at local shelters in Boston for at-risk and homeless youth. He received the International College of Dentists Humanitarian Award in 2019 for his exemplified and demonstrated passion for altruistic humanitarian service.

He is an avid learner and enjoys taking continuing education courses, particularly in prosthodontics, complex restorative techniques, and aesthetic dentistry. He has taken courses in advanced surgical principles and implantology. He is an active member in the American Dental Association and Massachusetts Dental Society.

Dr. Lam is an outdoor enthusiast and especially loves camping and hiking in New England’s wilderness. He routinely participates in kickboxing, yoga, and Metcon training in Somerville, MA.

Dr. Lam will prioritize your autonomy and comfort while delivering uncompromising modern dentistry at every visit. He loves what he does and he looks forward to taking care of your dental and overall health.


Dr. Shivani Patel is originally from Methuen, MA and graduated valedictorian from Methuen High School. From high school she got accepted into an accelerated B.A./D.M.D. program at Tufts University. She received her bachelor of arts in Developmental Psychology and then her D.M.D. from Tufts School of Dental Medicine in 2008. At Tufts School of Dental Medicine she received the Quintessence Award for Excellence in Restorative Dentistry and was also an Academic Tutor and Clinical Teaching Assistant.

Dr. Patel has been as Assistant Professor at Tufts School of Dental Medicine since 2011. She loves teaching part time and being in private practice on the other days. Her practice focuses on all age groups (she especially loves working with children). Her goal is to make each patient comfortable through thorough diagnosis and treatment planning allowing her to provide comprehensive care to all her patients. She enjoys a wide range of cosmetic and restorative dentistry, root canal therapy, teeth whitening, implant restoration, veneers, teeth alignment (straightening), crowns and therapeutic Botox therapy. Dr. Patel is a member of the Massachusetts Dental Society and the American Dental Association.  Dr. Patel attends continuing education courses including the Yankee Dental Congress in Boston to keep up-to-date with the latest advancements in dentistry.

Outside of the dental office, Dr. Patel enjoys traveling, teaching and learning Indian dance, and spending time with her family.

Meet The Team


Heidi – Patient Coordinator

Heidi has been a part of our team since November of 2003, as a patient coordinator. Prior to her numerous years of experience in the dental field, she received her BA from Rutgers University in New Jersey. Heidi helps our team with front desk duties, and assists our patients during check-in and check-out. She communicates with insurance companies, assists with billing procedures, answers incoming calls, and helps our patients in scheduling appointments. During her free time, you can find Heidi traveling, painting, gardening and cooking.


Kelly – Practice Manager

Kelly received her education in dental assisting from Quinsigamond Community College and joined our office in April of 2013. Since then, she has advanced her training becoming a certified dental assistant, a certified preventive functions dental assistant, and an AADOM Fellow. Kelly was also the vice president of the Boston Chapter of AADOM. As a practice manager, she helps patients at the front desk, communicates with insurance companies, schedules appointments, handles billing procedures, and supports the front desk with additional duties. Kelly loves spending time with her family at the beach, camping, gardening, and hiking. She recently finished an amazing hike up Mount Washington!


Patty – Registered Dental Hygienist

Patty is a registered dental hygienist, and has been practicing with our team since November of 2000. She received her Associate of Science degree in dental hygiene from Middlesex Community College, and holds her license to administer local anesthetic, while also being CPR certified. When she’s not at the office educating her patients about oral health, she is often gardening, making arts and crafts, or spending time with her friends and family.


McKayla – Registered Dental Hygienist

As a registered dental hygienist with our team, McKayla spends one-on-one time with her patients discussing oral health, and encouraging happy, healthy smiles. She attended Middlesex Community College, where she obtained her Associate of Science degree in dental hygiene, and has been with our team since April of 2018. McKayla is passionate about dental hygiene and loves motivating her patients to continually improve their oral health. She takes annual continuing education courses in order to keep up-to-date with the latest advances, and pass her knowledge on to her patients. She enjoys spending time with her family and friends, walking her dog, reading, traveling and learning more about real estate.

Dawn – Dental Assistant

Dawn joined our team in 2006 after obtaining her certificate in dental assisting from Bryman Institute. She is CPR and radiology certified, and has advanced training in CEREC crown fabrication. Dawn assists our doctors in various dental procedures, while also helping our hygienists and our front office team. She is passionate about living a healthy lifestyle, and enjoys spending her time reading, gaming, and crocheting.