Meet Our Doctors:


Dr. Matthew LeightonOriginally from Vestal, NY, I grew up in a family of seven with a sister and three brothers. My father and mother instilled in me the value of higher education and health professions at home and as a clerk in their pharmacy business. I quickly learned how to provide customer service and the value of relationships with our customers.

I received my Bachelor’s Degree in Mechanical Engineering from Rochester Institute of Technology in 1989 and worked in a nuclear power plant before returning to college life to become a dentist, a dream I have had since the age of eleven. I received my Doctorate of Dental Surgery from SUNY Buffalo School of Dental Medicine in 1994, then a residency certificate in General Practice from St. Clare’s Hospital, Schenectady, NY in 1995. I returned to my hometown to practice for a few years, then moved to Amherst, NH with my wife Cathy, and joined Dr.’s Kayser and Clark in 1998.

I have been caring tirelessly to deliver the highest quality dentistry to the patients of our practice as well as provide a safe and comfortable environment for them and our team. The level of customer service our team provides is unsurpassed in our community.

Dedicated to lifelong learning, I attend continuing education and participate in study clubs to keep abreast of the latest advancements and treatment techniques. I am a Dawson Alumni and a member of Spear. I am a member of the American Dental Association, the New Hampshire Dental Society and the Nashua Dental Society.

Outside of my professional life, I give back to the community as a board member for the Northern New England chapter of the Cystic Fibrosis Foundation. I volunteer as a coach for my son’s Ice Hockey team, I am an adult leader with Amherst Boy Scout Troop 613 and strive to be the best husband and father my family could ask for.


Dr. Valerie PereiraOriginally from Windham, NH, I moved to Connecticut to complete my higher education. I received my Bachelor of Science Degree in Physiology and Neurobiology from the University of Connecticut in 2013. In 2017, I received my Doctor of Dental Medicine Degree from the University of Connecticut School of Dental Medicine. I stayed in Hartford, CT for another year to attend the General Practice Residency program at Saint Francis Hospital and Medical Center.

In July of 2018, I left Connecticut and came to work at Clark & Leighton. Their commitment to patient care is perfectly aligned with my practice philosophy. As part of my commitment to higher learning and continuing education, I am a member of the American Dental Association, the Academy of General Dentistry, and the New Hampshire Dental Society.

Outside of dentistry, I enjoy swimming, reading, and knitting; as well as spending time with my husband and toy poodle.


Our highly skilled team includes three dental hygienists, two dental assistants, and four business/treatment coordinators; all focused on making your dental visit both comfortable and worry free.

Our entire team attends continuing education seminars on a regular basis, to ensure you receive the best possible dental experience.

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Supporting Our Community

We believe in supporting local programs and charities in our community.

+ Click to see a list of those we have had the privilege to help support.

Amherst Fire Dept.

Amherst Fourth of July Celebration

Amherst Garden Club

Amherst Holiday Tree Lighting Festival

Amherst Junior Woman’s Club

Amherst Lion’s Club

Amherst PTA Annual Play

Amherst Police Dept.

Amherst Recreation Dept.

Boy’s and Girl’s Club of Souhegan Valley

Bridges for Peace

CBM Cares Luau

Crotched Mountain Foundation

Cystic Fibrosis Foundation

Friend’s of the Amherst Town Library

Greater Nashua Dental Connection

Home & Hospice of Milford, NH

Community Hospice House Merrimack, NH

Kim J. Cates Memorial Scholarship Fund

Kitty Angels Annual Craft Fair

Holiday Toy Store (annually since 1987)

Gateways Community Service

High Mowing School

Hollis Elementary PTA Auction

Honor Flight New England

Milford Crop Walk

Milford High School Robotics Team

Milford Rotary Club

Milford Wadleigh Memorial Library

New Hampshire Food Bank

New Hampshire Humane Society

Pan Mass Challenge (Dana-Farber Cancer Institute)

Post 74 Legion Baseball (Brookline, NH)

Share Food Bank

Share Outreach

Souhegan High School First Robotics Team

Souhegan High School Hope for Gus Fun Run

Souhegan High School Project Graduation

Souhegan PTA Annual Play

Souhegan Scholarship Foundation

Special Olympics of New Hampshire

Susan B. Koman Walk to cure Breast Cancer

Trinity High School Annual Golf Tournament

Wilton Destination Imagination

Wilton Lyndeborough High School

Wounded Warrior Project

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Office Staff