Episode 20

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Published on:

1st Dec 2025

20: Think Fluoride Is Simple? Think Again – The Hidden Chemistry That Decides What Actually Works with Dr. Rob Karlinsey

What if the fluoride in your toothpaste is not all the same, and the form you choose could change how well it works?

In this episode of Dental Formulator’s Playbook, Dr. Rob and co host Tami break down the chemistry, formulation challenges, and clinical performance of the three fluoride salts approved for use in the United States: sodium fluoride, sodium monofluorophosphate, and stannous fluoride. They explain why each compound behaves differently, how abrasives influence stability, and how manufacturing history shaped which toothpaste formulas became global standards. The conversation also includes new research confirming the safety of community water fluoridation and debunks long standing myths about cognitive effects. This episode is essential listening for anyone who wants to understand why fluoride choice matters and how formulation truly determines efficacy.

🔍 Highlights ↠

• How sodium fluoride differs from sodium monofluorophosphate in activation and availability

• Why MFP requires plaque enzymes and saliva to release active fluoride

• Why MFP performs poorly for people with dry mouth

• The real reason MFP dominated formulas in the 60s and 70s

• How calcium carbonate abrasives blocked early sodium fluoride formulas

• How sodium MFP is made using a water free fusion process at 900 degrees Celsius

• The surprising global history of MFP and why early records are often wrong

• Why stannous fluoride made a major comeback for gingivitis and sensitivity

• The difference between fluoride uptake testing and enamel solubility reduction

• Why sodium fluoride excels in fluoride uptake but stannous fluoride excels in acid resistance

• How abrasives, zinc salts, pyrophosphates, and calcium ingredients can reduce free fluoride

• Why many modern “fluoride toothpastes” fail availability tests

• The importance of choosing the right fluoride salt for cavities, sensitivity, or gum health

• New 2025 research showing no cognitive harm from regulated water fluoridation

💡 Key Takeaways

• Not all fluoride compounds work the same, and their efficacy depends heavily on formulation.

• MFP is stable with calcium abrasives but requires saliva activation, which reduces performance for dry mouth users.

• Sodium fluoride offers the strongest fluoride uptake but is sensitive to competing ingredients.

• Stannous fluoride provides superior acid resistance and gum health benefits when formulated correctly.

📲 Connect with Dr. Rob (Robert L. Karlinsey, PhD)

🌐 Website: customdentalformulations.com

📄 Research Profile: Robert Karlinsey on ResearchGate

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About the Podcast

Dental Formulator's Playbook
The Dental Formulator’s Playbook is where science meets strategy in the world of oral health innovation. Hosted by Dr. Rob Karlinsey, a seasoned dental researcher and independent formulator, this podcast is your behind-the-scenes pass to what really goes into creating cutting-edge dental products.

Whether you're a dentist, a dental brand, or just someone curious about how toothpaste, rinses, and other oral care products are developed, you'll find practical insights and real-world takeaways in every episode. Dr. Karlinsey keeps it straightforward and engaging—no fluff, just clear, thoughtful explanations based on years of experience in the lab and the industry.

This show is all about helping dental professionals and product developers think differently, make better decisions, and stay ahead of the curve. If you care about science, results, and doing things the right way, you're in the right place.

About your host

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Robert Karlinsey

Dr. Robert L. Karlinsey is a scientist and formulator with almost 20 years’ experience in dental research. He earned a BS in Physics (University of Scranton) and PhD in Chemical Physics (Indiana University), with postdoctoral work in physical chemistry (Indiana University). As a visiting assistant research professor at the Indiana University School of Dentistry, his research led to an impactful encounter with Dr. George Stookey, and shortly thereafter, the formation of Indiana Nanotech, LLC (now known as Custom Dental Formulations, LLC), of which he spearheaded all research and small-scale manufacturing efforts. Dr. Karlinsey is the inventor of Nanotech’s functionalized tricalcium phosphate systems, which continue to help generate over $100MM in global product sales for a major dental manufacturer. As Principal Investigator, his work has received significant funding through Federal (National Institutes of Health), State (Indiana and Texas), and industry grants and contracts. His research in patented calcium phosphate technologies continue to help generate over $100MM in global product sales. Previously, Dr. Karlinsey has served as Chief Scientific Officer at Therametric Technologies, Inc, and adjunct professor of chemistry at the University of Indianapolis.

Dr. Karlinsey addresses clients’ needs in preventive and cosmetic dentistry, including fluoride- and fluoride-free remineralization, antiplaque/gum health, whitening systems, and more. He is actively involved in clinical and laboratory research designs and performance-backed, customized oral care formulation solutions. And, whenever possible, he favors natural, nature-derived, and/or sustainably sourced ingredients