Fluoride-Free Toothpastes for Caries Prevention: A Systematic Review of Clinical Evidence on Active Ingredients

Introduction

Caries remains highly prevalent worldwide.¹ The primary cause of caries is dental plaque, where bacteria metabolize sugars into acids that demineralize the mineral phase of the tooth structure. Therefore, reducing sugar intake and maintaining effective preventive oral care are two key strategies to lower caries risk.²

Toothpastes play an important role in preventive oral health care and caries prevention.³ In toothpastes, effective plaque removal is essential and can be achieved with cleaning abrasives; antibacterial agents can also be included.² However, there is a general trend away from using strong antibacterials such as chlorhexidine in oral care products due to concerns about resistance development as well as due to negative impact on the oral microbiome.^4,5 To strengthen and remineralize enamel, toothpastes can incorporate remineralizing agents.² Overall, toothpaste formulations, ingredients, and efficacy have continually evolved and improved.⁶

While fluoride compounds have been used in toothpaste for decades,⁴ various fluoride alternatives have been introduced in recent years, many of which are already used in commercial toothpaste products.⁵ One rationale behind fluoride-free concepts for toothpastes is that, although fluorides are frequently used around the globe, still caries remains highly prevalent globally,¹ so new approaches are needed. Additionally, there are ongoing discussions about potential side effects of fluoride, especially in children.⁶ These concerns include not only dental fluorosis,⁷ but also possible negative effects on the developing brain.^6,8,9 Although studies were conducted with fluoride in drinking water, it is important to note that, on one hand, infants and toddlers often swallow relatively large amounts of toothpaste,¹⁰ and on the other, dosing of fluoridated toothpastes for children is frequently excessive.^11–13

Taken together, there is a need for fluoride-free caries-preventing agents for the use in toothpastes. Several reviews have been published on fluoride-free anti-caries agents. A review titled “Non-Fluoride Anticaries Agents” published as early as 1994 classified fluoride-free active ingredients into several categories:¹⁴ phosphorus-containing agents, calcium-containing agents, antimicrobials and antibiotics, metals, and miscellaneous agents. While studies back then were mainly performed under in vitro conditions, the field of fluoride-free anti-caries agents has been shown to be highly dynamic, and the clinical evidence has grown significantly in recent years.

Recent review articles in this field focus on calcium phosphates including hydroxyapatite (HAP), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), calcium sodium phosphosilicate (CSPS), and β-tricalcium phosphate (β-TCP),¹⁵ as well as general reviews on agents specifically intended to prevent caries in primary dentition.¹⁶ There are also reviews focusing solely on single active ingredients, such as, hydroxyapatite,^17,18 arginine,^19,20 and xylitol,²¹ with in-depth literature analysis. Fluoride-free caries-preventing agents may differ between their modes of action, eg., some agents such as calcium-containing agents promote remineralization of early caries lesions, while others exert antibacterial/biofilm reducing effects.¹⁴

For patient-centered recommendations, it is important to know which fluoride-free anti-caries agents have been described in the dental literature and, most importantly, what the clinical evidence for these agents in caries prevention is. As toothpastes are the most widely used vehicle for daily caries prevention, this systematic review focuses exclusively on fluoride-free toothpastes. As outlined above, there are articles that have addressed fluoride-free agents; however, to our knowledge, a more recent and comprehensive overview that also considers newly published clinical trials is still not fully available.

The aim of this systematic review was to present a current overview on fluoride-free agents used in toothpastes for caries prevention and to summarize the clinical evidence in comparison to fluoride toothpastes. Additionally, the modes of action of those agents in caries prevention are presented. While the main focus of the present review was on in vivo studies, some findings from the past years were included to capture the latest developments in toothpaste technology regarding caries prevention.

Methods

The PICO Framework

For the literature search the following PICO framework was used:

P (Population): participants of all ages, with primary, mixed, or permanent dentition.

I (Intervention): the use of a toothpaste with an active ingredient that is not fluoride.

C (Comparison): a fluoride-containing toothpaste as control.

O (Outcome): a measurable oral health effect that is based on a caries estimation in vivo.

Databases

Informed by, but not fully sticked to the PRISMA guidelines for literature reviews (Supplemental Table S1), MEDLINE (via PubMed), and EMBASE (via Scopus) were screened for literature.²² Full texts and supplementary information were extracted for each publication. The search was limited to English-language publications and conducted on the 17th of October 2025 using the following inclusion and exclusion criteria. All studies conducted in vivo in humans as clinical trial, using a fluoride-free toothpaste, focusing on caries and were written in English were included in the synthesis. Studies on animals or in vitro studies, studies not directly focusing on caries (eg., plaque studies etc.), studies only comparing fluoride products, and studies comparing other products than toothpastes were excluded from the review.

The search terms, following the inclusion and exclusion criteria were as follows:

(“fluoride-free”:ti,ab OR “fluoride free”:ti,ab OR “non-fluoride”:ti,ab OR “non-fluoridated”:ti,ab OR nonfluoride:ti,ab OR “without fluoride”:ti,ab) AND (toothpaste:ti,ab OR dentifrice*:ti,ab) AND (caries:ti,ab OR “dental caries”:ti,ab OR cavit*:ti,ab) AND (“clinical trial”/de OR “randomized controlled trial”/de OR randomized:ti,ab OR “in vivo”:ti,ab) NOT (“in vitro”:ti,ab OR “in situ”:ti,ab OR mouthwash:ti,ab OR “mouth rinse”:ti,ab) NOT (“review”/de OR “systematic review”:ti,ab OR “meta-analysis”/de) (for EMBASE), where “ti,ab” refers to title and abstract search. The same terms were used for PubMed with adaptation to the requirements.

Qualitative Synthesis

Qualitative synthesis was conducted on the included studies, demonstrating caries-preventive efficacy of fluoride-free toothpaste agents. The randomized clinical trials were suitable for Cochrane Risk of bias (RoB) analysis.²³ For the RoB analysis, study authors used the Cochrane RoB 2 tool.

Results

According to the inclusion and exclusion criteria, the search was conducted on both databases, as described above (Figure 1). The search resulted in 59 publications of which 51 remained after de-duplication. Titles and abstracts were screened using Rayyan software by two authors (JE and PU). 17 studies were excluded because they lacked caries-specific endpoints, 6 that only investigated fluoride-containing products, 6 that did not investigate toothpastes, 4 were not clinical trials, and one could not be fully read due to non-English language (Chinese) [the English abstract states that the tested fluoride-free toothpaste was inferior to fluoride toothpastes in terms of remineralization]. After full text screening, two more studies were excluded due to a non-caries-related focus.

Figure 1 PRISMA flow chart depicting the selection of studies according to Page et al 2021.21

Table 1 Overview of Selected Studies

Thus, in total 15 studies were included for qualitative synthesis (Table 1). Those 15 publications can be divided into two different groups, comparing a fluoride toothpaste with either 1) an abrasive non-therapeutic placebo toothpaste, or 2) with a toothpaste containing an active ingredient for caries prevention. Four studies are part of the latter group showing toothpastes with either hydroxyapatite or arginine as active ingredients in different concentrations. All other 11 studies are comparing fluoride toothpaste with an abrasive comparator. All study details are presented in Table 1. The results of the 4 studies investigating the caries-preventing effect of an active ingredient will be briefly summarized as follows.

Three studies analyzed the caries preventing effects of fluoride-free hydroxyapatite toothpastes: Paszynska et al reported in a 1-year trial using the International Caries Detection and Assessment System (ICDAS) that a fluoride-free toothpaste was non-inferior to a 500 ppm fluoride toothpaste in children with primary dentition.³² Schlagenhauf et al demonstrated the non-inferiority of a fluoride-free hydroxyapatite toothpaste compared with a 1400 ppm fluoride toothpaste in adolescents undergoing orthodontic treatment, in a 6-month study using ICDAS.³⁴ In adults, Paszynska et al showed that in a 18-month trial that a fluoride-free hydroxyapatite toothpaste was non-inferior to a 1450 ppm fluoride toothpaste based on Decayed, Missing, and Filled Surfaces (DMFS) outcomes.³⁹ One study investigated the caries-preventive effect of fluoride-free arginine toothpaste: In a large 2-year Phase 3 trial, Yin et al showed that arginine was an alternative to a 1450 ppm fluoride toothpaste in children with permanent dentition.³⁷

The RoB analysis based on the Cochrane RoB2 tool of the 4 included clinical trials, indicated low RoB for all four considering all five domains (Figure 2).

Figure 2 Risk of Bias (RoB) analysis of the included clinical trials according to Cochrane RoB 2.23 Green plus indicating low risk of bias. D1= Randomisation process, D2 = Deviations from the intended interventions, D3= Missing outcome data, D4 = Measurement of the outcome and D5= Selection of the reported result.

Discussion

Discussion of Results

Sugar reduction is essential to prevent caries.² Besides that, toothpastes are used worldwide for caries prevention,³ and both toothpaste formulation and selection of ingredients have been significantly improved over recent decades.⁴⁰ Various toothpaste ingredients such as remineralizing agents, cleaning abrasives, and antibacterial agents can contribute to caries prevention.² Consequently, it is important not to focus on single ingredients, but rather on the caries-preventive efficacy of the entire toothpaste formulation.

While fluoride was the sole caries-preventing agent for many decades, this has changed.^17,18,37 Mainly due to ongoing discussions addressing potential side effects of fluorides,^6–9,41,42 and, despite its widespread use, caries remains prevalent globally.¹

In the past, many additives in toothpastes were evaluated only in combination with fluoride (eg., 1.5% arginine with 1450 ppm fluoride,⁴³ or 10% xylitol with 1100 ppm fluoride).⁴⁴ Consequently, the caries-preventive effect of the fluoride-free active ingredient itself could not be determined. Recent clinical trials have addressed this by analyzing fluoride-free toothpaste formulations for caries prevention as well (Table 1).

Arginine and hydroxyapatite have been evaluated as fluoride-free alternative in caries prevention (see Table 1 for all study details). The caries-preventing efficacy of arginine at two concentrations (1.5% and 8.0%) was analyzed in a multicenter two year, phase 3, trial in China among children aged 10–14 years.³⁷ However, regarding toothpaste formulations used in this study, it is noteworthy that the arginine toothpastes used a calcium carbonate base, whereas the fluoride control toothpaste used a silica base. Therefore, future studies analyzing the caries preventing effect of arginine could also include head-to-head comparisons using identical toothpaste bases. On the other hand, the hydroxyapatite study by Paszynska et al used identical toothpaste bases that differed only in their active ingredients: 10% hydroxyapatite versus sodium fluoride (1450 ppm fluoride).³⁹ Another significant limitation of the arginine study is the difference in baseline caries scores (DMFS [Decayed, Missing, and Filled Surfaces] and DMFT [Decayed, Missing, and Filled Teeth]) between participants in the arginine groups and the fluoride control group.⁴²

The caries-preventing efficacy of hydroxyapatite toothpaste has been evaluated across different age groups, ie., children,³² adolescents,³⁴ and adults,³⁹ in Germany and Poland. The non-inferiority of hydroxyapatite compared to fluoride in caries prevention was consistent across all three clinical trials. Building on this evidence, a fluoride-free hydroxyapatite toothpaste for children (Health Canada; Natural Product Number: 80117093) offers the following oral health effects, as validated by the Canadian Dental Association: “Cavity protection” and “Helps rebuild tooth enamel”. Two recent systematic reviews and meta-analyses on the clinical evidence for fluoride-free hydroxyapatite toothpastes in caries prevention have been published.^17,18 Both reviews conclude that hydroxyapatite prevents caries and remineralizes early lesions, indicating that it is a safe and effective alternative to fluoride across all age groups.

For a recent comprehensive meta-analysis that includes all three clinical trials on hydroxyapatite identified in the present review, we refer to Pawinska et al¹⁸ To the best of the authors’ knowledge, the clinical trial on arginine has not yet been included in a meta-analysis, presumably due to its recent publication (August 2025).

The risk-of-bias analysis was performed for the four clinical trials that demonstrated caries-preventive efficacy of fluoride-free actives. The risk-of-bias analysis demonstrates an overall low risk of bias for the arginine trial and the three hydroxyapatite trials (Figure 2), supporting the methodological quality of these studies.

Arginine and hydroxyapatite have different modes of action in caries prevention.

Arginine contributes to caries prevention because it is metabolized by arginolytic bacteria via the arginine deiminase system to produce ammonia (NH₃), which increases plaque pH and thus reduces its acidity and demineralizing potential.^20,45,46 However, because arginine provides neither calcium nor phosphate, it cannot directly remineralize early caries lesions. Arginine has a high safety profile, as it is a naturally occurring amino acid in the human body.⁴⁷

Hydroxyapatite, on the other hand, directly remineralizes early caries lesions and forms a protective layer on the enamel surface.^48–53 Additionally, hydroxyapatite acts as a calcium and phosphate reservoir within dental plaque and can increase plaque pH due to its buffering properties.⁵⁴ The overall safety of calcium phosphates, including hydroxyapatite, has been demonstrated, as shown in a comprehensive review article.⁵⁵

The present review also identified 11 studies in which fluoride-free toothpastes were used as placebo controls (Table 1). It is important to note that the inferior caries prevention observed in these studies, compared with fluoridated toothpastes, can likely be attributed to the use of simple abrasive formulations devoid of active anti-caries agents. The rationale for the use of these placebo toothpastes was to isolate and evaluate the purely mechanical effects of the toothpaste; accordingly, the formulations were intentionally not designed as anti-caries toothpastes and did not include caries-preventive ingredients. This contrasts with other studies that investigated active alternatives (arginine or hydroxyapatite), which were formulated to deliver anti-caries benefits (Table 1).

In general, children, in particular, have advantages when using fluoride-free toothpastes, because swallowing does not pose a fluorosis risk.^7,8 Moreover, fluoridated toothpastes for children must be used in very small amounts (up to two years: a grain-of-rice amount; ages 2–6: a pea-sized amount),⁵⁶ which significantly limits tooth-cleaning efficacy and might diminish caries prevention.⁵⁷ Fluoride-free toothpastes, on the other hand, can be applied in larger amounts, significantly increasing their cleaning efficacy.⁵⁷ Another group that may benefit from fluoride-free oral care products is pregnant women, since fluoride in drinking water has been reported to show neurotoxic effects on offspring.⁶ Beyond these groups, people of all ages may benefit from fluoride-free oral care products. Fluoride has been shown to be cytotoxic to gingival fibroblasts in an in vitro study, leading to the conclusion that fluoride concentration should be reduced (though this would likely diminish its efficacy) or that suitable substitutes for fluoride should be considered.⁴²

Another important consideration is the publication date of the trials on hydroxyapatite and arginine (Table 1). Because these studies were published recently, they were conducted according to contemporary clinical trial standards. By contrast, most trials evaluating the caries-preventive effect of fluoridated toothpastes versus placebo toothpastes are considerably older (see Walsh et al for details).⁴

Strengths and Limitations

The literature search included only clinical toothpaste trials that mentioned “fluoride-free” or similar terms in the title or abstract (see Section 2.2 for details), which avoids preselecting specific active ingredients and ensures an objective literature search. On the other hand, studies describing toothpastes solely by their active ingredients without explicitly stating they are fluoride-free could have been overlooked. Furthermore, studies that note the absence of fluoride only in the full text may have been missed. Also, the PRISMA checklist was not followed completely eg. no protocol was prepared in advance. The risk-of-bias analysis was performed only for clinical trials demonstrating caries-preventive efficacy of fluoride-free toothpaste agents, and no meta-analysis was conducted. For meta-analyses on fluoride-free hydroxyapatite toothpastes, we refer to.¹⁷

Outlook – New Approaches in Caries Prevention

In general, there has been a well-documented improvement and evolution of toothpaste technology.⁴⁰ Due to the increased global interest in fluoride-free toothpastes, there is a lot of ongoing research in the field of fluoride-free anti-caries agents. Recent clinical trials have analyzed fluoride-free hydroxyapatite toothpastes^32,34,39 and fluoride-fee arginine toothpastes³⁷ in the field of caries prevention. Besides these two agents, there are various other promising agents, including calcium compounds such as calcium hypophosphite,⁵⁸ antimicrobial peptides,⁵⁹ self-assembling peptides such as P11-4,⁶⁰ and probiotics.⁶¹ These approaches, as well as others, are promising for use in toothpastes and are candidates for further investigation in future clinical trials.

Conclusions

This review shows that clinical studies have demonstrated the caries-preventive efficacy of certain fluoride-free active ingredients in toothpastes. Furthermore, recent research has identified additional promising fluoride-free agents that could be incorporated into toothpaste formulations and merit evaluation in future clinical trials.