Dental caries is characterized as a hard tissue disease caused by the demineralization of tooth minerals and the destruction of organic matter owing to organic acids produced by bacteria breaking down carbohydrates, leading to damage and defects in teeth. Treatment of dental caries involves invasive procedures, making primary prevention before the onset of caries crucial[1].

Several methods have been suggested to prevent dental caries, including fluoride administration, fissure sealants, plaque control, and dietary adjustments. Fluoride inhibits the demineralization of the tooth surface and promotes remineralization of the demineralized areas[2]. The relationship between fluoride and teeth has been well established since 1916. Fluoride has shown significant effects for preventing damage to hard dental tissues (both systemically and topically) and in the repair of damaged tissues[3]. The Federation of Dentists International has stated that fluoride use is beneficial, safe, and effective for preventing dental caries[4]. Methods for fluoride use include water fluoridation programs, fluoride-containing toothpastes, fluoride rinses, and professional fluoride applications[5].

The use of fluoride toothpaste with 1000 ppm fluoride has been shown to prevent caries in both primary and permanent teeth[6]. Consequently, in Korea, the fluoride content in toothpastes had been regulated to 1000 ppm, and most commercially available toothpastes contain this amount[7]. The “Regulation on Approval, Notification, and Review of Quasi-drugs” was revised in September 2014, and the permissible fluoride content in toothpastes was increased from 1000 ppm to 1500 ppm, allowing for imports of toothpaste with higher fluoride content. Since 2020, domestically manufactured toothpastes have been permitted to contain 1450 ppm fluoride, and such products are now available for consumer purchase[8].

Public concerns about fluoride toxicity have persisted because excessive fluoride intake is known to cause diarrhea, vomiting, fluoride poisoning, and dental or skeletal fluorosis[9]. Children aged < 6 years are particularly at risk owing to their underdeveloped swallowing reflexes. Those aged < 3 years are especially vulnerable because this is a critical period for the formation of permanent tooth hard tissues[10], increasing the probability of dental fluorosis from excessive intake[11]. However, adverse effects of fluoride absorption typically occur only with excessive intake. To minimize the potential risks, various guidelines, including those from the American Dental Association, the European Academy of Paediatric Dentistry (EAPD), and the Korea Disease Control and Prevention Agency, recommend age-appropriate fluoride and toothpaste intake for infants and young children. These guidelines suggest using a smear or rice-grain sized amount of toothpaste for children less than 3 years of age, and a pea-sized amount for children aged 3 - 6 years. This approach aims to ensure proper fluoride exposure while minimizing the risk of excessive intake[12-14]. Despite numerous studies on the effects and characteristics of fluoride and guidelines on fluoride toothpaste use, there is a lack of research on fluoride toothpaste use in Korea.

Therefore, this study aimed to investigate the status and practices of fluoride toothpaste use. We also administered a survey to parents and children who visited the Yonsei University Dental Hospital to evaluate parental awareness of its benefits and risks. The survey focused on the actual use of fluoride toothpaste and the extent of knowledge of its benefits and risks.

Fluoride is recognized as an efficient and economical method of oral care that prevents dental caries and strengthens hard tooth tissues. Fluoride adheres to the crystal surface of teeth in the oral cavity, thereby protecting the tooth surface and preventing crystal dissolution. Furthermore, as the oral pH changes from acidic to neutral, fluoride has been shown to be absorbed into the enamel forming fluorapatite, which facilitates tooth remineralization and enhances tooth resistance to acidic environments[15].

In South Korea, the fluoride concentration in toothpaste had been regulated to an upper limit of 1000 ppm, with manufacturers producing and selling toothpaste at or below this concentration. However, several countries, including Germany, the United Kingdom, and the United States, have set their fluoride upper limit at 1500 ppm[16].

Recently, South Korea granted approval for manufacturing toothpaste containing 1450 ppm fluoride. Consequently, toothpastes with fluoride concentrations exceeding 1000 ppm have been introduced and marketed domestically in alignment with international standards. In 2022, South Korea revised its ‘2022 Oral Examination Dentist Counseling Manual’, recommending the use of toothpaste containing 1,000 to 1500 ppm fluoride. The manual advises using a smear or rice-grain sized amount of toothpaste for children aged 0 - 2 years, and a peasized amount for those aged 3 - 6 years[14]. However, this increase in fluoride content raises concerns regarding the potential side effects.

This survey examined parental criteria for selecting toothpaste for themselves and their children. Functionality (caries prevention, tooth whitening, gum improvement, and breath freshening) emerged as the primary consideration for adults, followed by those without specific criteria. This finding indicates that parents prioritize toothpaste efficacy, which is consistent with previous research[17] that identified functionality as the most influential factor in toothpaste selection. However, a significant proportion (19.6%) of parents without specific criteria indicated a lack of engagement in adult toothpaste selection, potentially leading to the purchase of familiar and readily available brands.

In contrast, most of parents reported selecting toothpaste for their children, prioritizing safe ingredients over fluoride concentrations. This disparity likely stems from the lower risk of toothpaste ingestion in adults than in children, allowing parents to focus more on functionality for themselves while emphasizing safety for their children. The selection of a fluoride concentration for children’s toothpaste has been attributed to a higher incidence of dental caries in pediatric and adolescent populations.

The majority of parents acknowledged the necessity of fluoride in both adults’ and children’s toothpaste; thus, demonstrating a high awareness of the presence and benefits of fluoride. However, awareness of the potential side effects was notably lower. A significant gender difference was observed in fluoride toothpaste awareness, with mothers showing greater interest than fathers. This suggests the need for increased promotion and information dissemination to fathers. Additionally, the level of awareness regarding fluoride toothpaste differed based on the child’s gender. However, this difference may be attributed to the sample characteristics in our study, where there were more female parents for male children compared to female children. Further research is needed to confirm and explore this relationship.

Most parents identified caries prevention as the primary benefit of fluoride. Information sources for obtaining fluoride-related information were diverse and included dentists, television broadcasts, and online platforms. Those aware of side effects primarily obtained information from digital media and personal contacts, with only 3 survey respondents citing medical professionals as their source of information. This highlights the potential gap in side-effects communication during dental and medical consultations.

These findings underscore the need for dental and medical professionals to provide comprehensive information on fluoride toothpaste usage, along with the potential side effects and precautions. Such guidance would enable parents to make informed decisions when selecting and using fluoride toothpaste for themselves and their children.

About 81.0% of parents reported that for their children they predominantly used children’s toothpaste, with low-fluoride toothpaste accounting for 40.5% of usage. According to Walsh et al.[18], toothpaste containing an average of 1000 ppm fluoride demonstrated a caries prevention rate of approximately 23%, whereas toothpaste with 2400 ppm fluoride showed a 36% prevention rate. However, toothpaste with an average fluoride concentration of 500 ppm did not exhibit significant caries prevention effects. This finding indicated that children using 500 ppm fluoride toothpaste may not receive adequate caries prevention benefits. Additionally, when comparing 1000 ppm and 1500 ppm fluoride toothpaste, the 1500 ppm fluoride toothpaste showed a tendency for higher remineralization effects, demonstrating a greater caries prevention effect[19]. Consequently, it is evident that parents should be informed and encouraged to select toothpaste with fluoride concentrations of 1000 ppm or higher for their children. Furthermore, for children with high caries risk, it is advisable to recommend 1500 ppm fluoride toothpaste.

Among households using either fluoride-free or fluoride-containing toothpaste, 42.3% of parents reported being aware of the fluoride content of their children’s toothpaste. Notably, the levels of awareness significantly differed based on the age of the parents and children. Parents of younger children, particularly those in infancy and early childhood, demonstrated greater concern and knowledge regarding the fluoride content of their children’s toothpaste than parents of school-age children.

These findings highlight the need for targeted education and guidance, especially for parents of older children, to ensure the appropriate selection and usage of fluoride toothpaste across all age groups. The data also highlights the importance of maintaining parental awareness and engagement in oral health practices throughout children’s developmental stages.

The practice of parents applying toothpaste to their children’s toothbrushes was predominantly observed in households with children aged < 6 years. Parents of children aged between 0 - 6 years generally reported the use of age-appropriate amounts of toothpaste. However, the majority of parents demonstrated a lack of awareness regarding the recommended toothpaste quantities for different age groups.

Notably, this study revealed that parents of children with “poor” or “very poor” oral health reported greater knowledge of the recommended toothpaste amounts. This finding suggests that parents become more attentive to preventive measures, such as fluoride use, when their children’s oral health is compromised.

The most common age for initiating fluoride toothpaste use has been reported as 3 - 6 years. Parents cited dentists, blogs, and television broadcasts as primary sources of influence in selecting to use fluoride-based toothpaste, indicating that dental professionals have been actively recommending fluoride toothpaste.

Parents of children aged 0 - 3 years preferred fluoride-free toothpaste, likely because of concerns about ingestion and potential side effects during the critical period of permanent tooth formation[10]. However, research has shown that the recommended daily fluoride intake for children is 0.05 - 0.07 mg/kg of body weight. The toxic dose of fluoride is reported to be 5 mg/kg, while the lethal dose is estimated at 16 mg/kg for young children and 32 mg/kg for adults. This indicates that fluoride toxicity occurs only when a considerably large amount of fluoride is ingested[20-23]. By using the American Academy of Pediatric Dentistry guidelines for toothpaste amounts, the actual fluoride intake from 1000 ppm toothpaste has been calculated as 0.2 mg/day in a rice-grain size (0.1 mg F) toothpaste application for children < 3 years and as 0.5 mg/day in a pea-sized (0.25 mg F) toothpaste application for children between 3 - 6 years[12]. These calculations indicate that the risk associated with the use of fluoride toothpaste in children aged 0 - 3 years is likely very low. Furthermore, the 2019 EAPD guidelines, the World Dental Federation, and the World Health Organization recommend the use of toothpaste containing at least 1000 ppm fluoride for children aged < 3 years[4,13,24]. Based on these findings, it has been suggested that fluoride toothpaste use should be recommended for children aged < 3 years and not just for children aged between 3 - 6 years, as previously reported. However, parental supervision and management are deemed necessary for children aged < 3 years to prevent potential side effects of excessive fluoride ingestion.

South Korea has implemented an oral health screening program for infants and young children alongside general health checkups. The participation rate in oral health screening has significantly increased over time[25]. Another study reported that 58.4% of parents cited oral health screening as the primary reason for their child’s first dental visit[26]. These findings are similar to those reported by the present study (61.0%). Prior to the screening, parents completed a questionnaire that enquired about fluoride use using questions such as the presence of fluoride in their child’s toothpaste, amount of toothpaste used, regular fluoride application, and whether they had received advice about fluoride.

This study found that dentists played a crucial role in providing information about the importance and necessity of fluoride to parents. Many parents reported receiving information from dental professionals about starting the use of fluoride toothpaste, and information on its effects and appropriate usage amounts shared during screening.

This study was limited by its focus on fluoride toothpaste, lacking consideration of other fluoride sources such as topical fluoride applications, fluoride rinses, fluoride supplements, and fluoride-containing foods. Additionally, it was limited by its focus on parents of children and adolescents who visited a specific department of a single university hospital in Seoul. This could have influenced the survey results owing to the participants’ potentially higher understanding of dental care. The impact of not only fluoride toothpaste but also other forms of fluoride intake should be considered in future studies. Parents visiting various institutions should be included to ensure a diverse and larger population is represented. Fluoride awareness among parents of children with disabilities, particularly in children who are unable to spit out toothpaste, should also be investigated. This could provide insights into the patterns and perceptions of fluoride toothpaste use in this population. Regional differences in fluoride toothpaste use and awareness among parents of children and adolescents could be further explored in follow-up studies. How parents of children who cannot spit out toothpaste perceive and use fluoride toothpaste should also be examined, which could inform the designing of guidelines for the proper use of fluoride toothpaste in these children.

This study investigated and evaluated the usage patterns and awareness of fluoride toothpaste use among parents of children and adolescents using a survey. Parents were knowledgeable in the necessity and importance of fluoride toothpaste; however, they had limited knowledge about its side effects. Female parents exhibited higher awareness of the presence of fluoride, its benefits, and its side effects in adult toothpastes. A trend was observed where younger parents and those with younger children showed higher awareness of fluoride content and appropriate toothpaste use for their children. While most parents reported using fluoride-containing toothpaste for their children, this study showed that more children started using fluoride toothpaste at ages 3 - 6 years (44.7%) than at ages 0 - 3 years (28.7%). Additionally, parents showed low awareness of the appropriate amount of toothpaste for their children. These findings highlight the need for efforts to educate parents about fluoride concentration in toothpaste and appropriate usage amounts, and to promote the timely initiation of fluoride toothpaste use. Such initiatives are necessary to improve the oral health of children and adolescents.