Meet our Dentists


Dr. Thomas Hartnett

Dr. Hartnett has been a Dentist and overall oral health provider for more than 35 years. He believes strongly in educating his patients on optimum oral health which helps to improve their overall health.  Dr. Hartnett graduated from the University at Buffalo School of Dental Medicine in 1979 and began his practice shortly thereafter.  In addition to growing his practice, Dr. Hartnett taught part-time at the University of Buffalo School of Dentistry for 15 years in the department of fixed prosthodontics.

Dr. Hartnett is a member of American Dental Association, American Endodontics Society, American Academy of Periodontics, American Association of Cosmetic Dentistry, New York State Dental Society, Eighth District Dental Society, American Association of Oral Systemic Health.

Dr. Hartnett lives in Allegany with his wife Marsha.  They have three children and three grandchildren.  When Dr. Hartnett is not working in his practice he enjoys skiing, sailing, snowboarding, golf and carpentry work.

Dr. Daniel Jammal

Dr. Hartnett is happy to welcome Daniel Jammal, DMD to our practice. Dr. Jammal joins our team of dentists to help take care of our growing dental family with a focus on general dentistry, sedation dentistry, sleep apnea and oral surgery.

Having grown up around teeth his whole life (his mother is also a dentist), Dr. Jammal has a great appreciation for the strong doctor/patient relationship. “He’s a very outgoing and friendly individual and we’re so happy to have him join us,” states Dr. Hartnett. “Dr. Jammal has a unique way of connecting with his patients. Not only is he a great dentist, he’s an all-around great guy too.”

A native WNY-er, he graduated from Boston University Dental School where he was awarded an Excellence in Oral Biology Designation upon graduation.

In his free time, he enjoys sailing, skiing, and spending time with family & friends and planning his upcoming wedding next year.

The Dental Team at Thomas E. Hartnett, DDS of Hamburg, P.C.


Patti Voit, RDH, Office Manager and Treatment Coordinator

Patti has worked in the dental field for over 20 years and started her career as a Dental Assistant for Dr. Hartnett.  In 2005 she earned her Associate Degree in Dental Hygiene from Erie Community College and is a member of the Dental Hygiene Honor Society.  She practiced dental hygiene in other dental offices after graduation,  and returned to Dr. Hartnett’s office in 2013 to assume the role of Office Manager and Treatment Coordinator.  In this role, she is responsible for managing the day to day operations of the practice and for making sure patients receive the quality care they deserve.

Like our Dentists, Patti is also a strong proponent in education and providing the latest education to patients, and is also a member of the American Association of Dental Office Managers.

Patti lives in Colden with her husband, Dan.  They have 3 sons and two beautiful granddaughters.

When she is not managing the practice, Patti enjoys spending time with her family and friends as well as going to the beach or hitting the ski slopes.


Diane Hagelin, RDH

Diane has been a Dental Hygienist for over 40 years practicing with Dr. Hartnett for over 30 years.   She loves her work and enjoys helping patients achieve overall oral health.

Diane graduated from Erie Community College with an honorary award from the Eighth District Dental Society.

Diane and her husband Eric, grew up in Hamburg, NY and still reside there today.  They have three daughters and 4 grandchildren.   When she is not practicing dentistry she is enjoys working in the garden, hiking, playing piano and most of all, being a Grandma.


Ellen Puckett, RDH

Ellen has been practicing dental hygiene for over 20 years and been with Dr. Hartnett’s practice for fourteen of them.  She is a graduate of Erie Community College where she received an Associate’s Degree in Applied Science. She was recognized with an award for patient management.

When she is not practicing dentistry she is working in her dance studio where she teaches children to dance.


Sandy Kwietniewski, RDH


Sandy has been a Dental Hygenist for 15 years and has been with Dr. Hartnett’s practice for 14 years.  She is a graduate of Erie Community College where she earned her degree in Dental Hygiene.

Sandy was raised in the Town of Hamburg, NY and still lives there today.  Sandy is the proud mother of two sons.

When she is not practicing dentistry, she enjoys music, being outdoors, and spending time with my family and friends.


Pattie Budzynski

Pattie has been the smiling face you see at Dr. Hartnett’s front desk.  She is the Dental Benefits and Treatment Coordinator and she has been working for Dr. Hartnett for over twenty years.

She lives in Lakeview with her husband Michael.  They have three daughters and three granddaughters. When she is not working in the practice she enjoys traveling, camping, gardening and spending time with family.