Topical fluoride hesitancy and opposition are significantly and positively associated: A cross-sectional study.

Introduction

Topical fluoride is an important part of preventive care provided during routine dental and medical visits [1] and is recommended by the U.S. Preventive Services Task Force and other professional organizations [2–4]. Fluoride prevents tooth decay by inhibiting demineralization of tooth enamel and promoting remineralization [5,6]. It is especially important for children at high risk for tooth decay, including those from low-income households, racial and ethnic minorities, and children with chronic medical conditions. In the U.S., 46% of children ages 2 to 19 years have tooth decay, making topical fluoride an important preventive intervention [7].

Despite strong evidence on the safety and effectiveness of topical fluoride [8,9], caregiver hesitancy and refusal are growing clinical and public health challenges [10,11]. Topical fluoride hesitancy is defined as “a delay in acceptance, thoughts of refusal, or refusal of topical fluoride despite availability” [12]. Being opposed is another term used to describe refusal. Caregivers may be hesitant about topical fluoride or refuse it for various reasons [13–16]. A 2018 study found that one-in-two caregivers had an inaccurate or incomplete understanding of fluoride varnish, a common modality of topical fluoride delivery in clinical settings [15]. Other studies have shown a significant association between topical fluoride refusal and immunization refusal [10,17], indicating general preventive care skepticism among some caregivers. This skepticism has become a more pressing issue as recent political changes associated with the U.S. presidential elections have suggested the possibility of a new federal push for eliminating water fluoridation [18]. Anecdotally, some U.S. dentists in clinical practice have reported an increase in the number of caregivers who are hesitant about or opposed to topical fluoride in the post-election period, which may increase further now that Robert F. Kennedy, Jr has been appointed as Secretary of the U.S. Department of Health and Human Services after being nominated by President Donald Trump and confirmed by the U.S. Congress. Previous qualitative research presented a five-domain model on reasons caregivers are hesitant about topical fluoride: thinking topical fluoride is not necessary, wanting to keep chemicals like fluoride out of their child’s body, thinking fluoride is harmful, thinking there is too much uncertainty about fluoride, and feeling pressured to get topical fluoride [12].

The prevalence of caregivers’ fluoride refusal and opposition is unknown because population-based studies do not exist. However, two smaller studies limited to mostly caregivers located in Washington state are informative. A 2014 pilot study estimated that 4.9% of caregivers refused topical fluoride based on a review of dental records for children in three dental clinics in the Seattle area [10]. A 2023 study reported that 32% of caregivers expressed some degree of opposition to topical fluoride [17].

Despite anecdotal evidence that the two phenomena of topical fluoride hesitancy and opposition are related, there is a dearth of empirical research assessing this relationship [19]. Evidence that hesitancy is a precursor to opposition would support efforts to target the former with the goal of preventing topical fluoride opposition and improving acceptance of fluoride among caregivers of children at high risk for tooth decay. The study goal was to test the hypothesis that topical fluoride hesitancy is positively associated with opposition.

Materials and methods

Results

Discussion

The study aimed to empirically evaluate associations between different measures of topical fluoride hesitancy assessed in three different ways (general, domain-specific, and severity) and topical fluoride opposition. Consistent with the study hypothesis, significant positive associations were observed between all the topical fluoride hesitancy measures and opposition.

First and most importantly, high degrees of topical fluoride hesitancy (82.9%) and opposition (39.1%) were observed. Although the study intent was not to assess prevalence, these estimates are informative nonetheless, as past studies have reported the prevalence of topical fluoride refusal. A 2014 study reported refusal prevalence as 12.7% and operationalized refusal with a single question asking if the caregiver had ever refused topical fluoride [10]. Both the current and previous studies were conducted in a limited number of study locations, which raises questions of how generalizable these reported prevalence rates are to other geographic and clinic sites. A 2023 study on COVID-19 vaccine hesitancy in underserved populations showed that hesitancy varied by geography [28]. Topical fluoride hesitancy and opposition may show similar geographic variation, which may be attributed in part to regional differences in political affiliation, with conservatism shown to be a determinant of vaccine hesitancy [29]. Vaccination mandates may be inconsistent with personal choice as an important value to politically conservative voters. Caregivers with conservative views may believe that public health measures, including fluoride, are an example of government overreach [30]. More caregivers in our study sample identified as liberal or very liberal (44.9%) than as conservative or very conservative (12.0%), potentially resulting in relatively lower prevalence of hesitancy in our study sample than might be observed in other more conservative geographic areas. In addition, our study sample was comprised of caregivers with a relatively high level of education – a factor that may lead to an overestimation of fluoride hesitancy and opposition. These findings underscore the importance of additional studies on fluoride hesitancy that are geographically and politically diverse as well as those that draw on caregivers from broader socioeconomic backgrounds. Cultural and psychological determinants should also be explored, given potential underlying mechanisms of these factors. Future studies are needed among caregiver populations across different states and practice settings. Similar to national studies of vaccine attitudes, a national, population-based study would help determine the prevalence of these fluoride-related phenomena, and enable assessment of potential sociodemographic and geographic variation in beliefs and behaviors [31].

Second, with regard to the association between topical fluoride hesitancy and opposition, although there is overlap between the two phenomena, topical fluoride hesitancy is not the same as topical fluoride opposition. A larger proportion of caregivers were hesitant about—but did not express any opposition to—topical fluoride. Among hesitant caregivers, 45.9% reported any opposition, whereas 97.3% of caregivers who expressed any opposition were hesitant. These findings have important clinical relevance. Large numbers of caregivers who accept topical fluoride during clinical visits for their children may have underlying concerns about fluoride that reflect a latent hesitancy. Some caregivers may not communicate these concerns to their child’s health care provider, which is worrisome from a patient-provider communication perspective. This is especially important if hesitancy is a precursor to opposition. Therefore, further research is needed to assess the causal links between fluoride hesitancy and opposition, specifically via longitudinal study designs that investigate the extent to which hesitancy across the various domains leads to opposition (e.g., designs that recruit new or expecting caregivers and follow them prospectively).

Third, there were substantively and statistically significant, positive associations between a variety of topical fluoride hesitancy measures and opposition. While there are no relevant studies to compare these findings to, notably, the results regarding the association of domain-specific hesitancy with opposition was generally dose-dependent. For example, the adjusted odds ratios for necessity-specific domain of hesitancy were 6.1 and 34.8 for those with moderate and high hesitancy, respectively. Longitudinal studies could help identify mechanisms underlying these associations and provide insight on the extent to which caregivers cross over from hesitancy to opposition.

Fourth, with respect to caregivers’ underlying rationales for hesitancy, the findings highlight specific reasons. More than 80% of caregivers in our study believed that topical fluoride was unnecessary (the necessity domain). The next most prevalent hesitancy domain was chemicals: 31.3% of caregivers viewed fluoride as a chemical to be avoided. These findings were consistent with results from the regression models where the adjusted odds ratios were highest among these two domains (chemicals and necessity, OR = 52.71 and OR = 40.38, respectively). Furthermore, among the caregivers who met the threshold for subscribing to two domains of hesitancy (approximately 9%), all subscribed to the necessity domain and one-half of them to both the necessity and chemicals domains. These findings suggest that chairside intervention efforts should focus on clarifying topical fluoride necessity by explaining to caregivers a child’s particular dental caries risk and addressing concerns caregivers may have that fluoride is a chemical. Communicating dental caries risk effectively to interested caregivers could include digital visual aids that display the teeth and show what intact but demineralized teeth look like. One possibility is the use of chairside fluorescence to show caregivers examples of early non-cavitated enamel caries lesions in their children, which are precursors to cavities that may require restorations [32]. There is also the possibility to demonstrate the beneficial effects of fluoride using these same chairside technologies. The feasibility, acceptability, and effectiveness of these approaches should be evaluated, especially with fluoride-hesitant caregivers.

Fifth, the findings provide insights to inform immediate strategies needed for caregivers of high-risk children who are hesitant about or express any opposition to topical fluoride. About 60% of caregivers in the study sample had children at high risk for caries, based on caregivers’ survey responses regarding their child having a history of cavities or high likelihood of getting a cavity in the future. Given clinical recommendations that topical fluoride application is indicated for children at high risk for caries [1], hesitancy and opposition may be warranted among caregivers with children who are low-risk children [33]. However, the proportion of caregivers who expressed general hesitancy in this study (82.9%) was much higher than the proportion of caregivers with low-risk children (40%), which underscores the need to proactively address topical fluoride hesitancy in clinical settings to all caregivers. Dental caries is a multifactorial disease linked to tooth-level factors (e.g., enamel defects), intraoral environment (e.g., cariogenic bacteria, hyposalivation, xerostomia), social factors (e.g., poverty, food availability), access to preventive dental care, and the balance between two main behaviors (fluoride exposure and sugar intake) [4]. If a caregiver does not want his or her child to receive topical fluoride during a health care visit, then a clinician should discuss with the caregiver alternative forms of fluoride, including fluoride toothpaste and fluoridated water. A 2022 study reported that topical fluoride-hesitant caregivers were four times as likely to favor fluoridated toothpaste over fluoridated water, presumably because dose, frequency, and ingestion can be controlled with the former [34]. Thus, not all fluoride-hesitant caregivers are hesitant about all forms of fluoride. In fact, daily exposure to fluoridated toothpaste through toothbrushing may yield greater oral health benefits at a fraction of the cost than professionally applied topical fluoride that occurs once or twice a year. Clinical strategies to address topical fluoride hesitancy and opposition may require dentists to overcome discomfort in talking to caregivers about fluoride-related decisions. Past studies show that 42.3% of dentists reported topical fluoride refusal as a growing problem, yet 37% reported feeling uncomfortable when speaking to caregivers who refused [35]. A 2023 study presented a model that showed how dentists responded to fluoride-hesitant caregivers with varying degrees of engagement [36]. While some dentists used a patient-centered and tailored approach, others used reductionist, detached, or insistent approaches [36], which may inadvertently increase hesitancy or lead to caregiver disengagement. Studies on evidence-based approaches to address vaccine hesitancy show that presumptive communication rather than participatory communication is associated with better vaccine uptake [37] though such approaches may not sustain behavior change in the long-term. A similar approach could be taken for fluoride, alongside other communication tools proven to be effective, such as motivational interviewing, decision aids, and diagrams for caregivers with lower health literacy [37]. On a larger scale, public health interventions such as broad and tailored community campaigns to build confidence in fluoride and positive reinforcement of fluoride uptake via immediate rewards are also evidence-based methods that may help to address hesitancy [37].

For caregivers who express any opposition to all forms of fluoride, the only feasible remaining option to reduce dental caries risk may be to address sugar intake. Sugar sweetened beverages (SSB) are the most common source of added sugars in U.S. children [38]. The American Academy of Pediatrics (AAP) recommends no SSBs for children under age 1 year and that daily 100% fruit juice intake be limited to four ounces for children ages one through three, four to six ounces for children ages four through six, and eight ounces for children ages seven through 18 [39]. A 2018 systematic review investigated education, technology, changes to physical access, and other intervention strategies to reduce SSB consumption and found that multiple strategies combined were successful, with the most common including individual education, group education, and pamphlets [40]. These interventions may be effective in educating caregivers about sugar intake. Nevertheless, while education is necessary in changing SSB intake, it is not likely to be sufficient. Behavioral interventions are needed for sustained and long-term behavior change [41]. Future research should focus on effective ways to communicate dental caries risk to caregivers as well as behavioral strategies to increase uptake of fluoride when appropriate and to reduce SSB intake.

Sixth, the analyses provide insight on modeling the relationship between hesitancy and opposition. The bivariate analyses indicate a common (e.g., caregiver race and political ideology) and a different set of confounders relevant in modeling various hesitancy measures and opposition. Future research should continue to identify relevant confounders in an effort to construct conceptually accurate epidemiologic models.

Limitations

There are two study limitations. First, surveyed caregivers were mainly recruited from a single urban area in Washington state and most caregivers were politically liberal (leading to potential underestimation of hesitancy and opposition) but were from a higher socioeconomic background (leading to potential overestimation). As such, the direction and magnitude of any potential parameter estimation bias are unclear. However, research on topical fluoride hesitancy, opposition, and refusal is nascent and the current study addresses a critical knowledge gap in the literature while serving as a starting point for additional studies. Our sample was comparable to the latest available U.S. Census Bureau data (2020, 2023) in terms of the proportion of white individuals and income distribution [42]. Our sample had less representation from Black and Hispanic and Latino caregivers. Our sample also had notably greater representation from Asian caregivers, nearly triple the prevalence in the population (17.9% vs 6.0%) [40]. For education, the sample had less representation from individuals who had less than a high school education and greater representation from caregivers having completed college or more [42]. This provides guidance on population subgroups that might be the focus of future studies. Second, the study design was cross-sectional, limiting the ability to draw causal conclusions. However, the study operationalized multiple domains of hesitancy, providing insight for future longitudinal studies that could help disentangle cause and effect and thus advance our understanding of the mechanisms linking hesitancy and opposition.

Conclusions

The high prevalence of fluoride hesitancy and opposition in this sample and the multifaceted nature of that hesitancy underscores the importance of dentists knowing how to identify and manage such behaviors in clinical settings. Dentists should feel empowered to talk to caregivers about fluoride-related decisions using patient-centered approaches. There is a need for research on the efficacy of various communication strategies tailored to the specific reasons for hesitancy, which would eventually allow for the development of evidence-based clinical management strategies.

In closing, the following conclusions are offered:

1. Significant positive associations were observed between topical fluoride hesitancy and opposition, though the two are not identical.
2. A large proportion of caregivers reported some degree of hesitancy about topical fluoride (81.3%) with a smaller but still relatively large proportion reporting some degree of opposition to topical fluoride (39.1%).
3. Additional studies on clinical approaches are needed to help dentists improve fluoride-related communications, especially with caregivers of children at high risk for tooth decay who are hesitant about or express any opposition to topical fluoride.

Supporting information

Acknowledgments

The authors would like to thank the caregivers who participated in the survey and the University of Washington Center for Pediatric Dentistry for allowing the study team to recruit participants from the clinic.