The Advantages of Using Fluoride-Free Oral Care Products with Hydroxyapatite
Dr. Hardy Limeback BSc, PhD (Biochem), DDS Toronto, Canada
Hardy Limeback is an emeritus professor of dental research at the Faculty of Dentistry at the University of Toronto, Canada. He served as Head of Preventive Dentistry, President of the Canadian Association for Dental Research, and in 2006 was a member of a committee of the National Research Council of the USA that addressed fluoride in drinking water. He is the author of more than 100 scientific articles and book chapters, as well as editor of the well-known textbook Comprehensive Preventive Dentistry.
He taught dental students and practicing dentists for nearly 40 years. In addition, he led a research laboratory focused on the effects of fluoride on teeth and bones, owned a dental practice, and worked part-time as a dentist. He remains active in dental research and is currently focusing on fluoride-free oral care products, for example those based on the active ingredient Hydroxyapatite.
Fluoridation preserves approximately one permanent tooth from cavities over a lifetime of exposure. The negative effects of fluoride intake far outweigh the benefits.
Dr. Hardy Limeback
Fluoridation: The Fluoride Era
For more than 75 years, the first measure for cavities has been to treat patients with fluoride. Frequent sugar consumption promotes the growth of plaque bacteria on the teeth, which convert sugar into acids. If left untreated, these acids gradually demineralize the teeth. The loss of minerals creates cavities into which bacteria can penetrate, which in turn can lead to a pulp infection and ultimately tooth loss.¹
The use of fluoride to prevent tooth decay dates back a long way and begins with fluoridation². Where it could not be added to drinking water, children received fluoride supplements³. Since the 1950s and 1960s, it has been added to toothpastes, and placebo-controlled studies have shown that it reduces cavities⁴. It is also found in mouth rinses⁵. Professionally applied fluoride gels were introduced, although these are currently often being replaced by fluoride varnishes. However, they may not offer any additional benefit for the general population compared to fluoridated toothpastes⁶.
Side Effects: Side Effects of Fluoride Intake
Throughout the entire 20th century, it was assumed that fluoride, in the amounts used to reduce cavities in humans, was safe, regardless of whether it was ingested through drinking water or in the form of dietary supplements, consumer oral care products, or those administered by professionals.
In the 21st century, however, research has shown that increasing fluoride exposure can lead to health damage that no longer justifies the widespread use of fluoride. Based on current knowledge, the use of fluoride potentially poses more health risks than it benefits the general population⁷.
Dental Fluorosis
From birth to the age of 6, children's permanent teeth are in the developmental stage. Excessive fluoride intake during the first three years of life has a permanent and negative effect on the incisors. This is referred to as dental fluorosis⁸. Severe dental fluorosis is now considered a health impairment⁹.
Excessive fluoride intake is mainly attributable to diet as well as the early and improper use of fluoride-containing toothpaste¹⁰. The treatment of unwanted dental fluorosis is very costly¹¹.
Effects of Fluoride on the Brain
In animal studies, fluoride has been shown to be neurotoxic¹². Even exposure to only small amounts of fluoride is now also being associated with lower IQ in humans. The U.S. National Toxicology Program recently conducted a comprehensive meta-analysis of all human studies linking low fluoride exposure both before and after birth to lower IQ, finding a consistent and statistically significant negative association with no discernible threshold¹³.
Further Health-Damaging Effects of Fluoride Intake
It is well documented that lifelong accumulation of fluoride can impair bone quality¹⁴ ¹⁵. While this may only be a concern for older individuals living in areas with relatively high fluoride levels in drinking water, the use of fluoride-containing toothpaste can also result in significant amounts of fluoride remaining in the mouth on a daily basis, particularly in young children¹⁶.
In people with end-stage kidney damage, fluoride can have a negative impact¹⁷, which is why it would make sense to use a fluoride-free toothpaste for daily dental care in these cases. There is now also evidence that excessive fluoride intake can impair liver and kidney health in otherwise healthy individuals¹⁸.
Endocrine Effects
The intake of fluoride, even in small amounts, can impair both sperm quality and sperm count in men¹⁹. In addition, it has been shown that there is a negative correlation with sex hormone levels in children of both sexes²⁰.
Fluoride has been used for decades as a treatment for hyperthyroidism; however, in healthy individuals, ingested fluoride can impair thyroid function²¹.
Fluoride Alternatives: The Search for Safe Fluoride Alternatives for Oral Care Products
In 2015, approximately 1.5 billion people worldwide used fluoride-containing toothpaste²², and the World Health Organization recently declared topical fluoride an essential medicine that may not be affordable in low-income countries²³.
Due to the many unwanted side effects of fluoride intake, fluoride-free toothpastes are becoming increasingly popular. For example, 1/3 of toothpastes sold in the United Kingdom are now fluoride-free²⁴. But do they actually work?
Researchers have tested many fluoride-free formulations of oral care products. Among the most promising are toothpastes and mouth rinses based on Hydroxyapatite (HAP)²⁵. Hydroxyapatite added to toothpastes is biomimetic (i.e., it mimics nature), as it has the same structure as the natural mineral of teeth and bones.
There is extensive clinical evidence that fluoride-free Hydroxyapatite oral care products protect against cavities in children and adults. Several clinical studies show that Hydroxyapatite prevents cavities²⁶ ²⁷ ²⁸. The first systematic review and meta-analysis regarding the cavity-preventing effect of Hydroxyapatite was published in 2021²⁹.
Hydroxyapatite is also an effective active ingredient for sensitive teeth, as more recent systematic reviews and meta-analyses show³⁰ ³¹. An additional benefit is that Hydroxyapatite has been shown to whiten teeth in a gentle manner³². Patients with defective enamel, known as Molar Incisor Hypomineralization (chalk teeth), can also benefit from Hydroxyapatite toothpaste³³.
Hydroxyapatite toothpastes have been approved for sale in many countries worldwide for years; however, in Canada and the United States they are still relatively unknown. With the approval of Hydroxyapatite toothpastes by Health Canada and validation by the Canadian Dental Association, families in North America now have alternatives to fluoride toothpastes and mouth rinses that safely and effectively provide benefits for their oral health.
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⁴ Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A. Fluoride toothpastes of different concentrations for preventing dental caries. Cochrane Database Syst Rev. 2019 Mar 4;3(3):CD007868.
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⁶ Yu L, Yu X, Li Y, Yang F, Hong J, Qin D, Song G, Hua F. The additional benefit of professional fluoride application for children as an adjunct to regular fluoride toothpaste: a systematic review and meta-analysis. Clin Oral Investig. 2021 Jun;25(6):3409-3419.
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⁹ National Research Council. 2006. Fluoride in Drinking Water: A Scientific Review of EPA's Standards. Washington, DC: The National Academies Press.
¹⁰ Levy SM, Broffitt B, Marshall TA, Eichenberger-Gilmore JM, Warren JJ. Associations between fluorosis of permanent incisors and fluoride intake from infant formula, other dietary sources and dentifrice during early childhood. J Am Dent Assoc. 2010 Oct;141(10):1190-201.
¹¹ Hui A. Olympia Benefits. What are veneers and how much do they cost in Canada? www.olympiabenefits.com/blog/what-are-veneers-and-how-much-do-they-cost-in-canada.
¹² Ottappilakkil H, Babu S, Balasubramanian S, Manoharan S, Perumal E. Fluoride induced neurobehavioral impairments in experimental animals: a brief review. Biol Trace Elem Res. 2023 Mar;201(3):1214-1236.
¹³ National Toxicology Program, Fluoride: Assessment for developmental-neurotoxicity, 2023. ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/ongoing/fluoride.
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¹⁵ Helte E, Donat Vargas C, Kippler M, Wolk A, Michaëlsson K, Åkesson A. Fluoride in drinking water, diet, and urine in relation to bone mineral density and fracture incidence in postmenopausal women. Environ Health Perspect. 2021 Apr;129(4):47005.
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¹⁹ Liang C, He Y, Liu Y, Gao Y, Han Y, Li X, Zhao Y, Wang J, Zhang J. Fluoride exposure alters the ultra-structure of sperm flagellum via reducing key protein expressions in testis. Chemosphere. 2020 May;246:125772.
²⁰ Bai R, Huang Y, Wang F, Guo J. Associations of fluoride exposure with sex steroid hormones among U.S. children and adolescents, NHANES 2013-2016. Environ Pollut. 2020 May;260:114003.
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²² FDI World Dental Federation. The challenge of oral disease–a call for global action. Oral Health Atlas. Second edition. Geneva, Switzerland. 2015. www.fdiworlddental.org/oral-health-atlas.
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²⁵ Limeback H, Enax J, Meyer F. Clinical evidence of biomimetic hydroxyapatite in oral care products for reducing dentin hypersensitivity: An updated systematic review and meta-analysis. Biomimetics (Basel). 2023 Jan 6;8(1):23.
²⁶ Schlagenhauf U, Kunzelmann KH, Hannig C, May TW, Hösl H, Gratza M, Viergutz G, Nazet M, Schamberger S, Proff P. Impact of a non-fluoridated microcrystalline hydroxyapatite dentifrice on enamel caries progression in highly caries-susceptible orthodontic patients: A randomized, controlled 6-month trial. J Investig Clin Dent. 2019 May;10(2):e12399.
²⁷ Paszynska E, Pawinska M, Gawriolek M, Kaminska I, Otulakowska-Skrzynska J, Marczuk-Kolada G, Rzatowski S, Sokolowska K, Olszewska A, Schlagenhauf U, May TW, Amaechi BT, Amadeusz H, Luczaj-Cepowicz E. Impact of a toothpaste with microcrystalline hydroxyapatite on the occurrence of early childhood caries: a 1-year randomized clinical trial. Sci Rep. 2021 Jan 29;11(1):2650.
²⁸ Paszynska E, Pawinska M, Enax J, Meyer F, Schulze zur Wiesche E, May TW, Amaechi BT, Limeback H, Hernik A, Otulakowska-Skrzynska J, Krahel A, Kaminska I, Lapinska-Antonczuk J, Stokowska E, Gawriolek M. Caries-preventing effect of a hydroxyapatite-toothpaste in adults: a 18-month double-blinded randomized clinical trial. Front Pub Health 2023 11.
²⁹ Limeback H, Enax J, Meyer F. Biomimetic hydroxyapatite and caries prevention: a systematic review and meta-analysis. Can J Dent Hyg. 2021 Oct 1;55(3):148-159.
³⁰ Hu ML, Zheng G, Lin H, Yang M, Zhang YD, Han JM. Network meta-analysis on the effect of desensitizing toothpastes on dentine hypersensitivity. J Dent. 2019 Sep;88:103170.
³¹ Limeback H, Enax J, Meyer F. Clinical evidence of biomimetic hydroxyapatite in oral care products for reducing dentin hypersensitivity: An updated systematic review and meta-analysis. Biomimetics (Basel). 2023 Jan 6;8(1):23.
³² Limeback H, Meyer F, Enax J. Tooth whitening with hydroxyapatite: A systematic review. Dent J (Basel). 2023 Feb 12;11(2):50.
³³ Amaechi BT, Farah R, Liu JA, Phillips TS, Perozo BI, Kataoka Y, Meyer F, Enax J. Remineralization of molar incisor hypomineralization (MIH) with a hydroxyapatite toothpaste: an in-situ study. BDJ Open. 2022 Dec 10;8(1):33.