General Dentists

John J. Ahern

John J. Ahern

Dr. John J. Ahern was raised in Syracuse, New York. He graduated from the College of the Holy Cross where he captained the football team in 1980. He then received his dental degree from Georgetown University. While at Georgetown, Dr. Ahern received the prestigious Fixed Prosthodontics Award.

Dr. Ahern moved to New Hampshire in 1985 following dental school and purchased a practice from Dr. Gene Larochelle with fellow partner Dr. Sean Nichols.

Dr. Ahern has been very involved within the community for the last thirty years, from coaching at all levels, to being an active member of the Greater Derry Boys and Girls Club Board of Directors.

Dr. Ahern lives in Londonderry, New Hampshire with his wife, Karen. He has three sons; Ryan, Cory and Tim. Ryan is married to Kate and his youngest son Tim is currently at Tufts Dental School.

Dr. Ahern enjoys all sports and is always trying to perfect his golf swing.

Sean Nichols

Sean Nichols

Dr. Sean Nichols attended Providence College, where he graduated with distinction, Cum Laude, with a bachelor’s degree in biology. He received his dental education from Georgetown University School of Dental Medicine in Washington D.C., graduating in 1985. He has been a partner in the Derry N.H. practice since 1985, and recently celebrated 30 years of private practice. He is also a partner in the Northeast Mobile Dental Service, a group of dentists and allied health professionals providing dental care to the elderly in long-term care facilities throughout the state.

He holds professional memberships in the American Dental Association, the New Hampshire Dental Society and the American Academy of Cosmetic Dentistry. Dr. Nichols enjoys all aspects of family dentistry and cherishes the long-term relationships he has developed with his patients and their families.

He has advanced training in cosmetic dentistry, including bonding, veneers, implants and CAD/CAM-computerized porcelain aesthetic restorations. He enjoys being involved in the community, a participant in the Alexander Eastman Foundation, the Community Health Service and is past president and a 25 year member of the Greater Derry Boys and Girls Club Board of Directors.

He participates each year in dental service trips with Remote Area Medical providing dental care to underserved or impoverished communities throughout the country.

He enjoys skiing, golf and traveling with his wife Donna and three children; Brendan, Kyle and Alyssa.

John Patrick Ahern

John Patrick Ahern

Dr. John Patrick Ahern was born in Essex Junction, VT, and raised in Marlboro, Mass. He earned a bachelor’s degree in biology from St. Anselm College in 1980, where he met and forged a friendship with the future Dr. Donald G. Hersey.

In 1984, Dr. Ahern graduated from Georgetown University School of Dental Medicine in Washington, D.C. He joined Dr. John J. Ahern and Dr. Sean E. Nichols as a partner in their Derry, NH practice in 1989.

Dr. Ahern was instrumental in the development of the Greater Derry Oral Health Collaborative School Based Dental Program and remains active today as an advisor and a provider. He also serves in an advisory capacity to the Dental Component of the Community Health Service, helping adults in need of low-cost dental care.

Dr. Ahern is a member of the International College of Dentist and the American Dental Association. He is active in the leadership of the New Hampshire Dental Society and is a member of the Granite State Study Club. He is CEREC Certified and completed certification in implant restorations through the 3i Corporation

Dr. Ahern and his wife, Kelly make their home in Londonderry, NH and are the parents of three adult sons Gregory, Brian and Martin.

Donald Hersey

Donald Hersey

Dr. Donald Hersey hails from Danvers, Massachusetts and Bucksport, Maine. He received his bachelor’s degree from St. Anselm College in 1981. Dr. Hersey graduated from Georgetown University School of Dental Medicine in 1985. Before moving to New Hampshire in 1983, Dr. Hersey practiced at the Total Dental Group in Waterford, Conneticut. While in Connecticut, Dr. Hersey received extensive training in the restoration of dental implants. In 2003, he earned his Invisalign certification, and recently reached Invisalign’s Premier-Provider level. He is also CAD/CAM Technology certified.

Dr. Hersey is a member of the American Dental Association and the New Hampshire Dental Society. He volunteers with the Alexander Eastman Foundation School Dental Program and the Community Health Service and is an active member of the Derry Rotary Club.

Dr. Hersey has four children; Megan, Erin, Sarah and Matthew. His spare time is spent playing golf wherever and whenever he can. Dr. Hersey is also a long standing member of Nashua Country Club.

Stephen Butterfield

Stephen Butterfield

Dr. Stephen Butterfield was raised in Derry, NH and graduated from Pinkerton Academy. He attended St. Anselm College where he graduated with distinction, Summa Cum Laude, with a Bachelor’s degree in biology. He received his dental education from the University of Connecticut’s School of Dental Medicine, graduating in 2004.

While in dental school Dr. Butterfield lead a dental mission trip to the Amazon River Basin in Peru. Following dental school, he completed a one year general practice residency at Hartford Hospital in Connecticut. Prior to joining the office Dr. Butterfield practiced in Bedford, NH.

Dr. Butterfield is excited about giving back to the community he grew up in. His dental knowledge covers all aspects of general dentistry for the entire family.

He enjoys hiking, mountain biking and spending time with his wife Gloria and son Benjamin.


Dental Specialists

mario abdennour

Mario E. Abdennour - Endondontist

Dr. Mario Abdennour is a microscope trained endodontist that specializes in conventional non-surgical root canal treatment as well as surgical root canal treatment.

Dr. Abdennour is a graduate of Washington University School of Dental Medicine where he received the Doctor of Dental Medicine degree in 1989. He was given the “outstanding clinical ability” award. Following his dental degree, he attended a postgraduate general practice residency at a U.S.C. affiliated hospital in California, graduating in 1990. He practiced dentistry in California for a total of eight years. In 1997 he entered a three year Advanced Graduate Endodontic Program at Harvard University School of Dental Medicine, receiving his Specialty certificate in Endodontics as well as a Master in Medical Sciences in Oral Biology in 2000.

Dr. Abdennour currently holds a faculty appointment as a clinical instructor at the Advanced Graduate Endodontic Program at Harvard School of Dental Medicine where he teaches surgical and non-surgical Endodontics. He has been lecturing Harvard Dental students annually, local component State Dental Societies in the areas of Endodontic Surgery and Non-Vital Intracoronal Bleaching.

Dr. Abdennour is a member at Real World Endo board of advisors, conducting lectures and seminars on Precision-Based Endodontics in the USA and Quebec Canada.

Dr. Abdennour is currently the Vice-President of the Massachusetts Association of Endodontists, member of the American Association of Endodontists, the American Dental Association, the Massachusetts Dental Society, the Harvard Odontological Society and the American Academy of Dental Sciences.

marc pearlstein

Marc Pearlstein - Periodontist

Dr. Marc Pearlstein graduated from the University of Pittsburgh School of Dental Medicine in 1992. Upon completion of a one-year General Practice Residency at Strong Memorial Hospital in Rochester, New York, he returned to the University of Pittsburgh to complete a three-year specialty residency in Periodontics. Marc has been in private practice in the Boston area since 1996 and specializes in treating gum disease (such as gum surgery) and performing implant surgery. His skills will be a true asset allowing us to provide more complex care in the comfort of our office. Marc enjoys golf and spending time with his wife and daughter.