Peter Trefle Harnois DDS
Peter Trefle Harnois DDS
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Dr. Harnois practiced dentistry in the Hinsdale community for over 40 years. A graduate of Ohio Wesleyan, he was a much-loved member of the Phi Kappa Psi fraternity and a Hall of Fame swimmer. He went on to graduate from the University of Illinois Chicago College of Dentistry. He was a superior clinical and cosmetic practitioner dedicated to his patients' health, happiness, and confidence. Through his local practice, he touched the lives of countless patients and gave them new opportunities through their dental health and smiles.
He lectured internationally training other dentists in minimally invasive techniques and emerging dental technology. His lifelong passion was making dentistry accessible, comfortable, and approachable, for patients and clinicians alike.
Peter is survived by his loving children, Grace Harnois, Madeleine Harnois, Patrick Harnois (mother Elise Harnois) and Isabel Harnois (mother Beatriz Chalas Harnois), as well as his siblings Carol Potter, Libby Harnois and Robbie Fast.
Peter was a man of endless energy, passion and dedication to the ideas, realms and people that he loved. He was so at home in nature, birdwatching, traveling to the coasts, the mountains, biking, walking – experiencing all that the outdoors had to offer. He adored different worlds, especially the comics formative during his adolescence, and was delighted to witness the explosion of the Marvel universe on the silver screen. He had a boundless imagination and gave his children, family, and friends access to the incredible worlds that he could see. He worked tirelessly to take care of those he loved, and everyone in his orbit felt his support. He gave without thought, and there are innumerable lives bolstered by his generosity and kindness.
A celebration of life will be held on Saturday, March 8, 2025, with an open house from 1:00 until 4:00PM at the Katherine Legge Lodge, 5901 S. County Line Road, Hinsdale, IL 60521. All interested in remembering him are welcome. Arrangements by Sullivan Funeral Home 630-323-0275 or sullivanfuneralhomehinsdale.com
To plant trees in memory, please visit the Sympathy Store.
Christine Ellsworth Coyne
May 1, 2025
I had been thinking of Dr. Harnois recently and decided to see if I could contact him. I was utterly surprised to hear about his passing. Dr. Don Thorne was our primary dentist, and I remember when Dr. Harnois came into the practice. He was always so positive, caring and professional. He will certainly be missed.
Trisha Gray
March 4, 2025
I knew Dr Harnois more on the professional side working with him on his dental lab cases- he was always such a kind, generous, and helpful man. He will truly be missed.
Colleen Gallagher
February 12, 2025
I feel so sad to see this news. I love in Ireland now but Dr Harnois was a family dentist for years, I recently received a new mouth guard and it made me think k of Dr Harnois. I looked him up and found that he had passed away, I feel so sad and also send so much love from Ireland!
Brian Hickey
January 17, 2025
Peter was our family dentist. We started with him when he was an apprentice for practice owner Dr. Don Thorne many, many years ago. I used to look forward to my dental appointment because of how he treated me, always with a smile and kindness. I had so many great times at the dentist as Peter always was generous with his willingness to give me enough n2o to actually enjoy a root-canal. He took care of my whole family with grace and charm. We will miss him! Brian
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Lawrence Ansilio
January 9, 2025
At every visit to Peter's office, he found time to joke with me, We also shared updates on our children. We reminiced over Indian Princess campouts with our daughters. Peter's dental care was suberb, and my family and I were happy to be his patients for over 30 years. We wish all the best to his family and his memory will stay with us!
Mari Lee Bellman
January 8, 2025
Dr. Harnois was our family dentist for 30 years and even after moving to Wisconsin 10 years ago, my husband and I traveled back to Hinsdale to see him because he was that good and we trusted him. There was no doubt about how much he cared for his patients and certainly no doubt about how much he loved his kids. Such a big loss to so many lives he touched.
Mari Lee and Floyd Bellman
Josee Martens
January 7, 2025
Dr. Harnois was such a passionate, caring dentist with an amazing bedside manner. He was always smiling and sharing stories about how amazing his kids are. I hope the world smiles on his kids the way their dad smiled on everyone he crossed paths with.
Nick and Carole Feagler
January 7, 2025
Dr. Harnois was the field of Dentistry's "poster child"! I am sure he comforted and encouraged countless people to never fear a dentist again.
He was our dentist for over 30 years, and was one of the kindest men we ever knew. He cared about everyone, and remembered the details of their lives in a remarkable way. He will be greatly missed by all who knew him.
Carole and Nick Feagler
Paula Fuller
January 6, 2025
I am so sorry for the family loss of a wonderful man
He was kind and so talented with his profession
I´m grateful for everything he did for my family and myself
God´s blessings during this difficult time
Holly DiFabio
January 6, 2025
Sending blessing of love and healing to all the family, especially Isla. He will be missed by all.
I worked with Peter and it was always a pleasure to see him and hear how much he loved you.
Katie Moran
January 6, 2025
I have so many great childhood memories when it comes to Peter! The summer we landed on the moon, sitting around the little black and white TV on the porch with the Harnois family. Peter decided it was a good time to do his impression of the Martian from Bugs Bunny. He got in a bit of trouble with his parents for that but it still makes me laugh. Or him, chasing Robbie, Libby and I around swatting at us with a rolled up comic book, "I am Thor son of Oden". Such a tremendous sense of humor! Wishing Peter peace and sending his entire family my deepest sympathies.
Katie Moran
Jerry Good
January 5, 2025
Dear Harnois Family,
My family have been patients of Dr. Peter for almost 40 years. He treated us with kindness and utmost professionalism- in fact, when I was having some surgery done he gave me his personal cell phone!
I also know what amazing father he was.
He will be greatly missed by not only family but his staff, patients, and friends.
With deepest sympathy,
Jerry Good
From the Staff of Sullivan Funeral Home
January 5, 2025
Offering our deepest condolences during this difficult time.
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