The benefits of using fluoride-free hydroxyapatite-based oral care products

For over 75 years, administering fluoride in patients experiencing dental decay has been the first line of defense. Frequent ingestion of sugars encourages the growth of plaque bacteria on teeth that convert sugar to acids. Unchecked, these acids slowly demineralize teeth. Mineral loss leads to bacterial invasion by means of the cavities that are formed and that can lead to infection of the tooth pulp and eventual tooth loss¹.  

The history of fluoride for preventing dental decay is extensive starting with fluoridation². Where it could not be added to drinking water, children were given fluoride supplements³. Since the 1950s and 1960s it was added to toothpastes and shown in placebo-controlled trials to reduce dental decay⁴. It is also added to mouthwashes⁵. Professionally-administered topical fluoride gels were introduced and these are being replaced by fluoride varnishes, but they may not provide additional benefit for the general population than simply using fluoridated toothpastes⁶.  

All during the 20th century, fluoride had always been assumed to be safe to administer in humans at the levels observed to lower dental decay, whether administered in the drinking water, supplements, consumer oral care products, or professional applications.  

However, research in the 21st century has shown that with increasing exposure to fluorides, there may now be unacceptable adverse health effects that do not justify its widespread use. The benefit today of the use of fluoride for the general public is considered minor compared to the potential adverse health effects⁷.

Dental fluorosis

Children from birth to age 6 have permanent teeth that are still undergoing development. Any excess ingestion of fluoride in the first 3 years of life will permanently and negatively affect the incisors that show when a child smiles. This is called dental fluorosis⁸. Severe dental fluorosis is now considered an adverse health effect⁹.  

Excess fluoride ingestion comes mainly from the diet, early introduction to fluoride toothpaste, and improper use of fluoride toothpaste¹⁰. Treating objectionable dental fluorosis is very expensive¹¹.  

Brain Effects of Fluoride

It has been established in animal studies that fluoride is neurotoxic¹². Exposure to low levels of fluoride in humans is also now linked to lowered IQ. The US National Toxicology Program recently conducted a comprehensive meta-analysis of all the human studies linking low levels of fluoride exposure both prenatal and postnatal, to lowered IQ, and found a consistent and statistically significant negative relationship with no apparent threshold¹³. 

Other negative health effects of fluoride ingestion

Endocrine

In 2015 about 1.5 billion people worldwide used fluoridated toothpaste²² and the World Health Organization recently declared topical fluoride as essential medicine, which may not be affordable in low-income countries²³. 

Because of the many troublesome side effects of fluoride ingestion, fluoride-free toothpastes have been gaining popularity. For example, 1/3 of toothpastes sold in the UK are now fluoride-free²⁴. But do they work?  

Researchers have been testing many fluoride-free formulations of oral care products. Among the most promising is hydroxyapatite (HAP)-based toothpastes and mouthwashes²⁵. Hydroxyapatite added to toothpastes is biomimetic (i.e., it mimics nature) in that it is the same structure that naturally occurs as the main mineral of teeth and bones. The clinical evidence that fluoride-free hydroxyapatite oral care products reduce dental decay in children and adults is extensive.  

Several clinical trials have been conducted to show that hydroxyapatite prevents tooth decay^26,27,28. The first systematic review and meta-analysis on hydroxyapatite’s caries preventing effect was published in 2021²⁹.  

Since hydroxyapatite is also an effective dentin desensitizing agent, it is useful for adults with problems with tooth sensitivity, as summarized in recent systematic reviews and meta-analyses^30,31. An added benefit is that hydroxyapatite has been shown to safely whiten teeth³². Patients who have had poorly formed teeth, called Molar Incisal Hypoplasia, can also benefit from hydroxyapatite toothpaste³³. 

Hydroxyapatite toothpastes have for years been approved for sale in many countries but are relatively unknown in Canada and the US. With Health Canada’s approval of the claims on hydroxyapatite toothpastes and the Canadian Dental Association’s validation of hydroxyapatite toothpaste, families in North America, can now choose alternatives to fluoride toothpastes and mouthwashes to safely, and effectively, provide a benefit to their oral health.

_References:

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_{² Mullen J; European Association for Paediatric Dentistry. History of water fluoridation. Br Dent J. 2005 Oct 8;199(7 Suppl):1-4.} 

_{³ Ismail AI, Hasson H. Fluoride supplements, dental caries and fluorosis: a systematic review. J Am Dent Assoc. 2008 Nov;139(11):1457-68.} 

_{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.} 

_{⁵ Marinho VC, Chong LY, Worthington HV, Walsh T. Fluoride mouthrinses for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2016 Jul 29;7(7):CD002284.} 

_{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.}

_{⁷ Ko L, Thiessen KM. A critique of recent economic evaluations of community water fluoridation. Int J Occup Environ Health. 2015;21(2):91-120.} 

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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.}

_{¹⁴ Chachra D, Limeback H, Willett TL, Grynpas MD. The long-term effects of water fluoridation on the human skeleton. J Dent Res. 2010 Nov;89(11):1219-23.}

_{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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_{¹⁷ Wimalawansa SJ. Does fluoride cause the mysterious chronic kidney disease of multifactorial origin? Environ Geochem Health. 2020 Sep;42(9):3035-3057.} 

_{¹⁸ Malin AJ, Lesseur C, Busgang SA, Curtin P, Wright RO, Sanders AP. Fluoride exposure and kidney and liver function among adolescents in the United States: NHANES, 2013-2016. Environ Int. 2019 Nov;132:105012.} 

_{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.} 

_{²¹ Griebel-Thompson AK, Sands S, Chollet-Hinton L, Christifano D, Sullivan DK, Hull H, Carlson SE. A scoping review of iodine and fluoride in pregnancy in relation to maternal thyroid function and offspring neurodevelopment. Adv Nutr. 2023 Mar;14(2):317-338.} 

_{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.} 

_{²³ Gkekas A, Varenne B, Stauf N, Benzian H, Listl S. Affordability of essential medicines: The case of fluoride toothpaste in 78 countries. PLoS One. 2022 Oct 19;17(10):e0275111.}

_{²⁴ Gupta A, Gallagher JE, Chestnutt IG, Godson J. Formulation and fluoride content of dentifrices: a review of current patterns. Br Dent J. 2021 Sep 21.} 

_{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.}