Fluoride content in children’s dentifrices marketed in Argentina

ABSTRACT

Fluoridated dentifrices are the most widely used formulations for caries prevention and control.However, there is great concern regarding legislation on the use of fluoride formulations inearly childhood from the standpoint of avoiding increased risk of fluorosis while at the sametime achieving a concentration that ensures anticaries activity.

Aim

The aim of this study was to evaluate the stability of fluoride concentration in the mainchildren’s toothpaste brands marketed in Argentina.

Materials and Method

Twenty different brands of children’s toothpaste were evaluated by analyzing the concentration oftotal fluoride (TF), total soluble fluoride (TSF) and ionic fluoride (IF) in two or threesamples of each brand. Each sample was analyzed in duplicate using an ion-specific electrodecalibrated with fluoride standards, and the results were expressed in ppm (µg F/g).

Results

TF was found to be lower than stated by the manufacturer in 85% of the brands analyzed. TFconcentration found in fluoride toothpastes ranged from 651.5 to 1090.4 μg/ml F-, while TSFranged from 504.2 to 915.5 μg/ml F, and IF from 298.6 to 838.2 μg/ml F-.

Conclusions

The formulation and fluoride content in children’s toothpastes marketed in Argentina vary greatlyaccording to brand. In all the samples, TF concentration was lower than 1500 ppm F-, and TSFconcentration was lower than 1000 ppm F-, the minimum amount necessary to ensure anticarieseffect. This indicates the need for improved formulations and regulations.

INTRODUCTION

Dental caries is a dynamic, biofilm-mediated disease caused by the production of acids by cariogenicmicroorganisms. Its development is modulated by dietary habits and influenced by a combination ofbiological, behavioral and social factors ^{1, 2} , including the anatomical characteristics of the toothsurface, salivary flow and composition, oral microbiome composition, and exposure to fluoride. Fluoridepromotes remineralization and inhibits demineralization ³ .

Although dental caries can affect all age groups, its consequences are particularly significant inchildren, in whom the disease is associated with pain, school absenteeism, emotional distress, anddiminished quality of life1. There has been a great effort to control dental caries in recent decades,with an essential role being played by dentifrice formulations. However, other non-bacterial pathologiessuch as enamel defects, which are also studied in the area of cariology, require attention too ⁴ .

Among preventive measures, fluoridated formulations – particularly toothpastes – have proven highlyeffective in reducing the incidence of caries. As products intended for daily oral hygiene, they deliverfluoride consistently to the oral environment, thereby supporting remineralization and inhibiting cariesprogression ^{3, 5-8} .

Concerns have been raised regarding the use of fluoridated toothpastes during early childhood, primarilydue to the potential risk of dental fluorosis ^{8, 9} . However, fluorosis results from chronic excessivefluoride ingestion during enamel formation, regardless of the fluoride source, and not from appropriatetopical use ^{8, 10} . Although caries and dental fluorosis both require attention,it is important tohighlight that the critical period for fluorosis development is limited to the first 6–8 years of life,whereas caries risk persists throughout the individual’s lifetime, beginning with the eruption of thefirst tooth. Caries leave consequences and increase healthcare costs ^11-12 .

Fluoride toothpaste should be associated with tooth brushing as from the eruption of the first tooth.Considering both caries prevention and the risk of fluorosis, toothpastes with 1,000 to 1,500 ppm oftotal fluoride are recommended for children, with at least 1,000 ppm in soluble form ^{6, 13-15} . However,many toothpastes intended for children contain low fluoride concentration and therefore lack anticavityefficacy ⁷ . These may only be recommended for children under 3 years of agewith a low risk of cavitiesand a high risk of developing fluorosis in the permanent upper central incisors due to regular exposureto high fluoride intake from sources other than fluoridated toothpaste, such as food, especially if theylive in an area with fluoridated water ⁵ .

Due to concerns about the risk of fluorosis, Mercosur legislation only prioritizes the safety offluoridated toothpaste to the detriment of its anticaries potential, as it only establishes thatfluoride (F) concentration in the toothpaste shall not exceed 1,500 ppm, without establishing thesoluble fluoride concentration ¹⁴ . Therefore, some toothpastes on the market contain more than1,000ppm (F), but with a high concentration of insoluble salts, and several others are formulated with lessthan 1,000 ppm F because it is allowed by legislation, which is not in accordance with the best currentscientific evidence ^{6, 9, 14-16} .

The aim of this study was to determine the fluoride content in toothpaste brands recommended for childrenin Argentina.

MATERIALS AND METHOD

Sampling

A survey was conducted through websites, supermarkets and pharmacies to identify all commerciallyavailable toothpaste brands intended for children in Buenos Aires, Argentina. A total of 13 brandsand 20 different formulations were identified and acquired from various retail sources. For eachbrand, three distinct lots within the expiration date were purchased. All products were included inthe analysis. Each sample was encoded, and the analysis sequence was randomized using MicrosoftExcel to ensure blind evaluation (Table 1).

Table 1. Dentifrices for children marketed in Argentina and analyzed in this study.

Code	Brand	Country	Lot1 Lot2 Lot3	Abrasive stated	Source of (F)	Total Fluoride stated (ppm or %)	Other information stated
A	BUCALTAC	Argentina	06/24 07/23 07/25	CaCO3/ Hydrated Silica	MFP	700
B	CHICCO Niños 6-24 meses	Italy	0POL5053	Hydrated Silica	NaF	1000	Xilitol
C	CREST Kids	Greece USA	0434GR 31984354P1	Hydrated Silica	NaF	0,243%
D	COLGATE Kids	Brazil	2277BR122K 2195BR121C 2185BR122C	Hydrated Silica	NaF	1100
E	COLGATE Kids Zero	Mexico	1277MX111H 2039MX112H 1242MX111H	Hydrated Silica	NaF	1100
F	COLGATE Smiles	Mexico	2206MX1116 2132MX1126 2036MX1116	Hydrated Silica	NaF	1100
G	COLGATE Teens	Brazil	153BR122G 2034BR122K 2230BR121G	Hydrated Silica	NaF	1100
H	ELGYDIUM Niños 2/6 años	France	G00015 G00005 G00008	Hydrated Silica	Amine fluoride	500	Silyglicol
I	ELGYDIUM niños 3/6 años	France	G00043 G00039	Hydrated Silica	Amine fluoride	1000	Silyglicol
J	ELGYDIUM Junior 7/12 años	France	G00036 G00033 G00011	Hydrated Silica	Amine fluoride	1400	Silyglicol
K	FARMACITY	Argentina	11011 30711 05521	CaCO3/ Silica	MFP/ NaF	700
L	FLUOROGEL Chiquitos	Argentina	14585 14577 14589	Hydrated Silica	NaF	543	Xilitol 10%
M	FLUOROGEL Junior	Argentina	02604 02605 02602	Hydrated Silica	NaF	1086	Xilitol 10%
N	FRESH DENT Kids	unknown	220405 220102 220407	CaCO3/ Hydrated silica	MFP/ NaF	1000
O	GUM	Argentina	220921 220307 220516	Hydrated Silica	NaF	1100
P	JUNIOR SMILE (Dia)	Argentina	09521 11211 24321	CaCO3/ Hydrated silica	MFP NaF	700
Q	ODOLITO	Brazil	2221BR122C 2095BR122C 2221BR121C	Hydrated silica	NaF	1100
R	ORAL B Kids	Mexico	21434354P0	Hydrated silica	NaF	1100
S	ORAL B Stages	Mexico	2146435402 2192435401 2172435401	Hydrated silica	NaF	1100
T	SENSODYNE PRO-ESMALTE Niños	Slovaquia	20502KWC 13092KWA 11032KWC	Hydrated silica	NaF	1100

Sample information: code, brand, country of origin, lot numbers, abrasive substance stated,source of (F), total fluoride stated (ppm or %) by manufacturers and other informationstated.

Determination of fluoride concentration

Fluoride concentrations were determined following the protocol described by Cury et al. ¹⁷ . Eachsample was analyzed in duplicate, where 90 to 110 mg (± 0.01 mg) of each sample were weighed andhomogenized under vigorous stirring with 10 mL of distilled water until a suspension was obtained.Two 0.25 mL aliquots of each suspension were transferred to test tubes to determine theconcentration of total fluoride (TF) and soluble fluoride. The remaining suspension was centrifugedat 3,000 g for 10 minutes at room temperature to separate the insoluble fluoride bound to abrasives.

For each lot, two 0.25 mL aliquots of the supernatant were transferred to test tubes to determine theconcentration of total soluble fluoride (TSF) and to other tubes to determine the ionic fluoride(IF) concentration. All test tubes received 0.25 mL of 2.0 M HCl. TF and TSF tubes were incubated at45 ºC for 1h. All samples were neutralized by adding 0.5 mL of 1.0 M NaOH and buffered with 1 mL ofTISAB II (acetate buffer, pH 5.0, containing 1.0 M NaCl and 0.4% CDTA), and analyses were performedto determine the fluoride content.

Specimens were analyzed using the potentiometry method with an ion-specific electrode (Orion 96-09)coupled to an ion analyzer (Orion EA-740; Orion Research). Prior to analysis, the electrode wascalibrated using standard fluoride solutions with final concentrations of 0.5, 1.0, 2.0, 4.0, 8.0,16.0, and 32.0 μg/mL (ppm F).

Data analysis

A linear regression equation correlating the logarithm of fluoride concentration in the standardswith the measured electrode potential (mV) was calculated for each calibration (r² > 0.999) usingGraphPad Prism software. This equation was applied to determine the fluoride concentration in eachsample, expressed in parts per million (ppm or μg/g F).

RESULTS

This study analyzed 720 aliquots corresponding to 56 samples (1-3 lots per brand) of 20 brands ofdentifrices for children (Table 1). Sixty-five percent wereformulated with sodium fluoride (NaF), 5% were formulated with sodium monofluorophosphate (MFP) alone,15% combined NaF with MFP, and 15% used amine fluoride as the active agent. Regarding abrasivecomponents, 80% contained hydrated silica, and the other 20% had a mixture of CaCO3 and hydrated silica.

In 85% of the evaluated brands, the measured total fluoride (TF) was significantly lower than the amountstated by the manufacturer. Only three brands – H, I and K – had TF concentrations exceeding theirlabeled values.

The concentration of TF found in the fluoride dentifrices ranged from 651.5 to 1090.4 μg/ml F-, TSFranged from 504.2 to 915.5 μg/ml F, and IF ranged from 298.6 to 838.2 (Table 2).

Table 2. Concentration (μg/ml F-) of total fluoride stated and TF, TSF and IF found in the analysis ofdentifrices sold in Argentina .

Dentifrice label information (μg/ml F)	Fluoride (μg/ml F)	Mean	CI 95% (LL-UL)	p-value Student one-sample test
A (700)	TFa*	651.5	627.1 - 675.9	<0.001
	TSF	566.1	511.8 - 620.3
	IF	471.9	409.7 - 533.9
	TFa-TSF*	85.5	23.2 - 147.7	0.012
B (1000)	TFa	961.3	771.4 - 1151.1	0.662
	TSF	711.7	626.6 - 796.6
	IF	556.8	464.7 - 648.8
	TFa-TSF*	249.6	122.1 - 377.1	0.001
C (1500)	TFa*	772.3	731.6 - 812.8	<0.005
	TSF	504.2	498.7 - 509.6
	IF	466.6	456.5 - 476.5
	TFa-TSF*	268.1	225.6 - 310.6	0.001
D (1100)	TFa*	989.7	823.5 - 1155.9	<0.005
	TSF	772.4	739.1 - 805.7
	IF	709.8	694.4 - 725.1
	TFa-TSF*	217.3	71.9 - 362.7	0.007
E (1100)	TFa*	891.2	845.6 - 936.9	<0.001
	TSF	713.7	677.4 - 749.9
	IF	447.1	353.6 - 540.5
	TFa-TSF*	177.5	117.5-237.6	0.001
F (1100)	TFa*	880.9	819.3 - 942.4	<0.001
	TSF	508.6	474.7 - 542.5
	IF	298.6	187.7 - 409.4
	TFa-TSF*	372.3	335.3 - 409.2	<0.001
G (1100)	TFa*	954.2	916.4 - 991.9	<0.001
	TSF	760.5	711.7 - 809.3
	IF	680.2	614.9 - 745.3
	TFa-TSF*	193.6	144.2 - 243.1	<0.001
H (500)	TFa*	871.2	803.4 - 938.8	<0.001
	TSF	653.7	553.4 - 753.9
	IF	496.0	478.1 - 513.8
	TFa-TSF*	217.4	116.4 - 381.5	<0.001
I (1000)	TFa	1058.6	987.5 - 1129.7	>0.05
	TSF	764.7	711.6 - 817.6
	IF	597.9	506.9 - 688.8
	TFa-TSF*	293.9	271.1 - 316.7	<0.001
J (1400)	TFa*	1090.4	1054.5 - 1126.2	<0.001
	TSF	868.8	801.2 - 936.3
	IF	758.4	680.1 - 836.8
	TFa-TSF*	221.6	133.6 - 309.6	<0.001
K (700)	TFa*	849.0	804.6 - 893.4	<0.001
	TSF	770.0	702.8 - 837.1
	IF	472.4	280 - 664.8
	TFa-TSF*	79.0	35.8 - 122.1	0.002
L (543)	TFa*	977.0	952.1 - 1001.9	<0.001
	TSF	775.2	756.3 - 794.1
	IF	368.4	230.6 - 506.1
	TFa-TSF	201.8	161.9 - 241.8
M (1086)	TFa*	855.6	831.6 - 879.5	<0.001
	TSF	829.1	800.1 - 858.1
	IF	767.1	752.7 - 781.4
	TFa-TSF*	26.4	4.8 - 48.2	0.021
N (1000)	TFa*	837.1	809.2 - 864.9	<0.001
	TSF	796.8	780.3 - 813.2
	IF	760.6	735.9 - 785.2
	TFa-TSF*	40.3	8.7 - 71.8	0.017
O (1100)	TFa*	975.1	951.9 - 998.3	<0.001
	TSF	910.7	896.7 - 924.7
	IF	833.2	784.7 - 881.7
	TFa-TSF*	64.4	32.2 - 96.6	0.001
P (900)	TFa*	890.4	846.5 - 934.3	<0.001
	TSF	843.6	818.3 - 868.8
	IF	815.8	779.3 - 852.2
	TFa-TSF*	46.8	2.4 - 91.3	0.04
Q (1100)	TFa*	899.7	861.6 - 937.7	<0.001
	TSF	813.5	802.1 - 824.9
	IF	786.4	726.8 - 845.9
	TFa-TSF*	86.2	43.9 - 128.5	0.001
R (1100)	TFa*	911.0	896.3 - 925.5	<0.001
	TSF	915.5	902.1 - 928.8
	IF	838.2	823.9 - 852.3
	TFa-TSF	-4.5	-24.9 - 15.8	0.635
S (1100)	TFa*	892.9	853.1 - 932.8	<0.001
	TSF	853.8	832.7 - 874.7
	IF	824.6	811.2 - 837.9
	TFa-TSF*	39.1	6.4 - 71.9	0.023
T (1100)	TFa*	968.5	935.9 - 1001.1	<0.001
	TSF	896.3	846.2 - 946.4
	IF	784.7	762.3 - 807.1
	TFa-TSF*	72.2	28.6 - 115.7	0.004

Abbreviations: IF, ionic fluoride; TF, total fluoride; TSF, total soluble fluoride.

*Statistical significative differences (p <0.05)

DISCUSSION

This study aimed to evaluate the fluoride content in children’s toothpastes marketed in Argentina byassessing total fluoride (TF), total soluble fluoride (TSF) and ionic fluoride (IF), which are crucialfor understanding the potential anti-caries effectiveness of these formulations.

Regarding geographic origin, 40% of the products were manufactured in Argentina, followed by Mexico(20%), France (15%), Slovakia (5%), Greece (5%) and Italy (5%). These origins may involve differences inregulatory frameworks, manufacturing standards, or formulation practices that could influence fluoridecontent and availability. Previous studies on fluoride concentrations in dentifrices have primarilyfocused on products intended for adult use. In Argentina, for example, available data from Cury etal. ¹⁸ and Valadas et al. ¹⁶ have assessed adult formulations.

It is important to note that children’s dentifrices contain flavoring agents to make them more appealingby improving taste and scent. These components can also provide breath-freshening benefits by maskingodors and creating cooling or warming sensations. However, rather than merely encouraging regular use,pleasant flavors in children’s toothpaste may increase the risk of accidental ingestion ^{19, 20} . This isof particular concern because during the enamel development phase, children younger than 8 years old areat risk of developing dental fluorosis, a condition that causes enamel discoloration and, in severecases, affects enamel structure ^{21, 22} .

Therefore, current guidelines recommend that adults and caregivers supervise children’s toothbrushingusing fluoridated toothpastes with standard concentrations (1,000–1,500 ppm F), while ensuring that onlyage-appropriate amounts are applied ¹² .

The above highlights the importance of knowing the amount of fluoride content in each toothpaste,especially in those marketed for children. In its 2022 consensus statement, the InternationalAssociation of Paediatric Dentistry (IAPD) ²³ recommended brushing children’s teeth twice daily withfluoridated toothpaste containing 1,000–1,500 ppm of fluoride. The guideline emphasizes adjusting theamount of toothpaste to the child’s age (“smear” for children under 3 years; “pea-sized” for ages 3–6),rather than reducing fluoride concentration. Even with the recommendation to reduce the quantity and notthe concentration of toothpastes, 25% of toothpastes in Argentina contain less than 1,000 ppm. There isevidence suggesting that using low-fluoride toothpastes in children increases the risk of caries inprimary teeth ¹³ .

Anticaries activity is related to the available soluble fluoride concentration, which must be at least1000 ppm. While laws in USA, Canada, Australia and Chile require dentifrice labels to specify theconcentration of soluble fluoride, Argentina follows Mercosur legislation14, which only establishes thatthe maximum concentration of TF in a toothpaste should be 1500 ppm, whether for adults or children. Thesame is true in Brazil and Mexico ⁶ .

In the current study, in 100% of the samples, the soluble fluoride concentration was lower than the 1000ppm suggested by scientific evidence. The total fluoride (TF) levels in 85% of the analyzed brands werelower than those stated by the manufacturer, except for Dentifrices Elgydium niños 2/6años, Elgydium niños 3/6 años and Farmacity, whichcontained higher levels than stated. However, even when the concentrations were higher than stated, theywere still well below the 1,500ppm limit established by Mercosur legislation.

Several of the evaluated brands have also been assessed in previous studies conducted in Latin America.For example, the values we found for brands E and F were much lower than those reported by Chavez etal.15 in Peru, and Leite Filho et al. ⁶ in Brazil and Mexico. The concentration we found in brand F wasalso lower than those reported by Loureiro et al. ²⁴ in Uruguay and Valadas et al. ⁹ in Brazil. BrandsR, S, D and G in our study presented slightly lower fluoride values than those reported by Valadas etal. ⁹ , and brands D, G and H contained lower concentrations than thosereported by Leite Filho etal. ⁶ in Brazil. Brands C, D, R and S in our study contained lower concentrations than samples fromMexico reported by Leite Filho et al. ⁶ . On the other hand, brand O was found to have levels similar tothose reported by Valadas et al. ⁹ .

The findings suggest that most children’s dentifrices marketed in Argentina do not meet the statedfluoride content, potentially reducing their effectiveness in preventing dental caries. The presence oflower soluble fluoride levels highlights the need for regulatory revisions to ensure compliance withscientific recommendations and maximize anticaries benefits.

This study did not include an analysis of the chemical interaction between fluoride and the abrasive usedin each toothpaste, which can affect fluoride solubility and bioavailability. Future research shouldexplore how specific abrasive components influence fluoride stability over time, particularly afterproduct exposure to air or during repeated use, to better simulate real-world conditions. Additionally,longterm stability studies could help determine whether the soluble fluoride content declines over theshelf life of these products.

CONCLUSIONS

Children’s toothpastes marketed in Argentina showed substantial variability in formulation and fluoridecontent. Although all products complied with the regulatory upper limit of 1,500 ppm total fluoride(TF), none of them contained the minimum recommended concentration of 1,000 ppm total soluble fluoride(TSF) necessary to provide effective anti-caries effect. These findings suggest the need to revisecurrent regulatory policies to ensure that fluoride content is both accurately labeled and aligned withevidence-based thresholds for anticaries efficacy.

Funding Statement

This work was supported and financed by the Universidad de Buenos Aires (UBACYT20720160100).