Meet the PDX Biotech Team

Like you, at PDX BIOTECH LLC we work as a team, for the good of your patients and to empower your team. With over a century of professional experience across our core team and another 100+ years among our board of clinical advisors, we have had ample time to consider what we are about. 

Our core values include:

We run a lean operation to make sure we can deliver OraStripdx to your team at an affordable price so the value of our test can be realized for the good of your patients.

As a team ourselves, we are from diverse backgrounds so our complementary strengths can come together to help your team communicate to your patients’ families the critical importance of oral health care to their family members’ long-term wellness.

Our company was founded, and OraStripdx was launched, because the data were just too compelling to ignore. Simply put, the thiols that we measure have been proven in clinical studies to track the progress of active periodontal disease, a lifelong condition that must be consistently managed.

From the very beginning we have made giving back a core of our identity. We have sent product around the world to those seeking to provide better oral health care. In the US we have supported rescue organizations as well as veterinary teams working with the unhoused. We have also provided product to educators of the next generation of veterinary teams.


Business Team

Reggie Gresham


30 years of successful business experience. Capping off a successful career as an IT sales executive, Reggie joined the PDX team in 2021 to head up sales and marketing. Reggie gives back by mentoring at-risk youth, providing them an accessible positive role-model, and through an organizational leadership role in 100 Black Men.

Biochemistry Team

Tony Burgess-Cassler PhD

Head of R&D and Manufacturing

35 years of successful biotechnology and diagnostics experience, including over a decade in animal health. After earning his doctorate in biochemistry from the University of Illinois, Tony did postdoctoral research at the University of Wisconsin and then worked as a researcher for the U.S. Department of Agriculture. Entering the diagnostics industry, he was an inventor of the first human saliva test for HIV and was lead developer of OraStripdx, having been with PDX BIOTECH since the very beginning. Tony gives back by addressing issues of food insecurity, driving deliveries for the local Food Bank. Tony is co-author on two peer-reviewed published clinical studies validating the OraStripdx technology.

David McClure PhD JD


25 years of pharmaceuticals and medical device experience, including over 15 years in animal health. David has worked on enzymes of sulfur metabolism since 1987; his graduate research at the University of North Texas, where he earned a doctorate in biochemistry, was on a Salmonella enzyme that produces hydrogen sulfide. A registered patent attorney, David has worked with the OraStripdx technology for 20 years and ended up liking the product so much he bought the company. In previous industry roles, David was head of Regulatory, Intellectual Property, and R&D. David gives back by working with migrants and other persons experiencing housing insecurity who face challenges with the legal system. David is co-author on three peer-reviewed published clinical studies validating the OraStripdx technology.

Board of Clinical Advisors

Jan Bellows


As president of the Veterinary Dental Foundation and past president of the American Veterinary Dental College, Dr. Jan Bellows is an unparalleled leader among veterinary dentists. Dr. Bellows is first author of the current (2019) American Animal Hospital Association (AAHA) Dental Care Guidelines for Dogs and Cats.alth.

Mary Berg

BS, RVT, RLATG, VTS (Dentistry)

Mary Berg is the most sought-after veterinary dental technician specialist in the US and is second author of the 2019 AAHA Dental Care Guidelines for Dogs and Cats. Mary is president of Beyond the Crown Veterinary Education, providing on-site and remote accredited continuing education to veterinary practices seeking to strengthen their dentistry programs.ealth.

Brook Niemiec


As first author of the 2020 World Small Animal Veterinary Association Global Dental Guidelines, and board-certified in veterinary dentistry in both Europe and the US, Dr. Brook Niemiec is recognized as a global leader in veterinary dentistry. Dr. Niemiec is past president of the Academy of Veterinary Dentistry (AVD) as well as the AVD representative to the World Small Animal Veterinary Association.

Kara Burns

MS, MEd, LVT, VTS (Nutrition), VTS-H (Internal Medicine, Dentistry)

Kara Burns is a thought leader in veterinary nutrition and dentistry and is a prime mover in empowering veterinary nurses and veterinary technicians to take initiatives to enable their teams to deliver ever-improving care for patients. Kara is Editor in Chief of Today’s Veterinary Nurse, the official veterinary nursing journal of the North American Veterinary Community (NAVC), and Director of Veterinary Nursing Development at WellHaven Pet Health.