Introduction
Oral diseases are a significant health burden worldwide, affecting about half of the world’s population (World Health Organization, 2025). In the United States, improving access to oral health services and reducing oral disease burden remain public health priorities (Office of Disease Prevention and Health Promotion, 2024c). At the same time, Healthy People 2030 identified health literacy as a central focus for improving health, well-being, and equity (Office of Disease Prevention and Health Promotion, 2024b, 2024a). Health literacy serves as a cornerstone of effective health care delivery. It facilitates patient participation in care, enhances patient outcomes, and subsequently increases the effectiveness of the health care system (Rikard et al., 2016).
Health Literacy
A systematic review by Estrela et al. (2023) indicated that health illiteracy correlates with poor overall health, higher hospitalization rates, and increased emergency care use. This correlation is especially significant in chronic disease management, where patients face challenges in comprehending complex treatment regimens, adhering to prescribed medications, and recognizing early signs of complications. Patients with limited health literacy are 1.5 times more likely to experience poor health outcomes than those with adequate health literacy (Yeo et al., 2024). The population of women and children have faced significant challenges, including financial limitations, limited access to food assistance programs, difficulties obtaining care, and low levels of oral health literacy (Lieneck et al., 2023).
Oral Health Literacy
Health literacy also holds significant importance in dental health care. Research has established the connection between oral health and general health. Oral diseases correlate with systemic disorders, including heart disease, diabetes, and respiratory infections (Beyene et al., 2021). The high prevalence of caries is partly because many dental services have often been dismissed as a nonessential component of health systems (Foote et al., 2023). Low OHL can lead to poor oral hygiene practices, inadequate preventive care, and a tendency to rely on emergency services for dental issues, thereby exacerbating existing health problems. For instance, D’Agostino et al. (2023) found that patients with low OHL are twice as likely to skip regular dental checkups, resulting in a higher likelihood of dental issues, tooth decay, and gum disease.
Oral health literacy (OHL) extends beyond reading ability. It reflects a person’s capacity to access, process, interpret, and apply oral health information and services in ways that support appropriate decisions and behaviors (Horowitz & Kleinman, 2008; Jones et al., 2015). Low OHL has been associated with poorer oral health knowledge, weaker preventive behaviors, and less favorable oral health outcomes in some populations, although the strength and consistency of these relationships vary across studies (Firmino et al., 2017, 2018). Effective communication can help narrow this gap. Reviews of patient-provider communication emphasize the value of plain language, interactive dialogue, and techniques such as teach-back to reduce misunderstanding and promote adherence (Horowitz & Kleinman, 2012; Nouri & Rudd, 2015).
Oral Health Literacy in Community Settings
These issues are especially relevant in community-based and safety-net settings that are often underrepresented in the existing literature. Free dental clinics often serve patients facing financial, linguistic, cultural, and structural barriers to care. Such barriers can affect both access to services and the ability to understand and act on oral health information. California-based research with dental providers has highlighted the importance of communication training, plain-language materials, and language-concordant approaches when serving diverse patient populations (Tseng et al., 2021). In addition, oral/general health integration frameworks emphasize that both individual literacy and organizational communication practices shape patients’ ability to navigate care (Kleinman et al., 2021). For these reasons, baseline data from these environments may help educators and clinicians tailor communication strategies and identify practical interventions that support equitable care.
The Present Study
The purpose of this study was to examine baseline OHL levels among patients attending a free dental hygiene clinic, and whether OHL varied by gender, age, and socioeconomic status. Evidence suggests that gender-related factors may influence preventive dental service utilization, patient–provider communication, and the ability to understand and apply oral health information, with men having overall poorer oral health literacy (Lee et al., 2022; Lipsky et al., 2021). Age accounts for variations across the lifespan that may affect health knowledge, experiences, and behaviors (Meyer-Hofmann et al., 2026). Household income, a proxy measure of socioeconomic status, is a well-documented determinant of health because a higher income level is associated with access to resources, affordability of care, and health-related opportunities, all of which may influence outcomes (Darin-Mattsson et al., 2017).
Methods
Study Design and Setting
This study used a cross-sectional quantitative design. Data were collected at a free dental hygiene clinic in Anaheim, California, that provided preventive dental hygiene services, oral hygiene instruction, and screening-related care to underserved community members. The study included a primary patient survey component.
Ethical Approval
This study was approved by the William Howard Review Board, protocol no. IRB 004 signed by IRB representative. All participants provided informed consent before participation.
Patient Participants and Recruitment
Adult patients aged 18 years or older who presented for dental hygiene care during the study period were eligible to participate if they were able to provide informed consent and complete the survey in English or Spanish. Patients with severe dental anxiety or acute pain were excluded. Patients were approached during clinic visits and invited to complete the survey voluntarily using a standardized script. Data were collected from June 3, 2025, through June 20, 2025.
Measures
Patient OHL was measured with the Health Literacy in Dentistry scale short form (HeLD-14), a validated 14-item instrument developed to assess multiple dimensions of OHL, including access, understanding, support, utilization, economic barriers, receptivity, and communication (Jones et al., 2015). The HeLD-14 was selected for its robust psychometric properties, including high internal consistency (Cronbach’s α = 0.87) and validity across diverse populations (Jones et al., 2014).
Each item was scored using a 5-point Likert scale ranging from 1 (“without any difficulty”) to 5 (“unable to do”). The possible range of summary was shown after recoding of 5 to 0, 4 to 1, 3 to 2, 2 to 3, and 1 to 4. Higher scores indicated higher OHL. As part of the survey, subjects also self-reported their gender, age and household income.
Data Collection and Management
Patient surveys were completed electronically using SurveyMonkey during clinic visits. After obtaining written informed consent, a unique identifier number was associated with the subject’s survey to protect their identities, ensuring results remained anonymous. Data were stored in password-protected files accessible to the investigator.
Data Analysis
Survey responses were analyzed using descriptive and inferential statistical methods. Mean and standard deviation scores were calculated for the overall HeLD-14 score and individual items. HeLD-14 scores were compared by gender, age group, and socioeconomic status, using Kruskal-Wallis tests due to the non-normal distribution of the data.
Results
Patient Characteristics
A total of 183 adult patients participated. Respondents who completed the survey in English were 120 (66%) and 63 respondents (34%) completed the survey in Spanish. The sample was evenly divided by gender, with 91 respondents (50%) identifying as female, 88 (48%) as male, and 4 (2%) as nonbinary. The largest age group was 25-34 years (33%), followed by 18-24 years (18%) and 55-64 years (15%). Reported household income varied, although 26% of respondents preferred not to answer. Demographic distributions are presented in Table 1.
No statistically significant differences in total OHL scores were identified across the demographic variables examined. OHL did not differ by gender, H(2) = 1.63, p = .44; by age group, H(6) = 4.83, p = .57; or by household income, H(5) = 5.18, p = .39 (Table 1). Within this clinic sample, these findings suggest that overall self-reported OHL was relatively similar across the gender, age, and income categories included in the analysis.
Baseline Oral Health Literacy
Item-level and total OHL descriptive statistics are presented in Table 2. Overall, patients reported relatively high OHL. The mean total HeLD-14 score was 46.72 (SD = 7.80) out of a highest possible score 56. At the item level, most mean scores ranged from 3.09 to 3.62 on the recoded 0-4 scale, suggesting that participants generally experienced little difficulty with the oral health literacy tasks represented in the instrument. Question 6 of the HeLD-14 had a noticeably lower mean score of 2.62 (SD = 1.29). This question asked whether participants were able to pay from their own pocket for a dental prescription. This question was not as relevant as the others, since participants were patients receiving free dental hygiene services.
Discussion
This study evaluated OHL among adults receiving care at a free dental hygiene clinic. Two findings deserve emphasis. First, the patient sample demonstrated generally high self-reported OHL. Second, total OHL did not differ significantly by gender, age, or income in this clinic population.
The composite HeLD-14 scores indicated a generally strong understanding of oral health information, with most patients reporting they could interpret and apply oral health knowledge with little or no difficulty. These findings are consistent with previous research suggesting that structured access to dental services, even in low-income settings, can foster higher levels of health literacy when paired with supportive educational environments (Muscat et al., 2020; Nutbeam & Lloyd, 2021).
These findings should be interpreted cautiously. High average scores do not mean that every patient had uniformly strong OHL. One survey item had a noticeably lower mean score than the others, (Question 6) suggesting that specific aspects of oral health understanding, access, or application may remain challenging. The HeLD-14 is multidimensional, and a generally favorable total score can still mask targeted areas of difficulty. For this reason, even clinics serving seemingly high-literacy populations may benefit from communication strategies that assume misunderstanding is possible and proactively reduce literacy demands.
Statistical analysis using the Kruskal-Wallis test indicated no significant differences in OHL based on gender, age, or SES. The absence of statistically significant differences across gender, age, and income contrasts with some prior literature linking lower literacy with social disadvantage or reduced access to care (Firmino et al., 2017). One potential explanation for this discrepancy may be the educational emphasis and culturally responsive practices already embedded within the clinic’s service model. The clinic has protocols and patient centered policies in place that require each patient to be treated as an individual and provided with high quality, whole patient care.
Limitations
Several limitations should be acknowledged. The study was conducted at a single clinic over a short period, which limits generalizability. The patient sample was based on volunteer participation among those presenting for care, introducing the possibility of selection bias. The data were self-reported and did not include objective clinical outcomes, actual behavior change, or longitudinal follow-up. Income was used as a proxy for SES, and other potentially important variables, such as educational attainment, language preference, prior dental experiences, and health insurance status, were not analyzed in the reported results.
Future research should examine how different models of educational delivery of oral health information, such as mobile apps or digital media, can affect OHL outcomes across different groups within a free dental hygiene clinic. Longitudinal studies could also explore whether high literacy scores effectively translate into oral health behaviors, such as fewer missed appointments and higher preventive care. These studies would help to highlight whether high scores are indicative of putting knowledge into practice.
Conclusions
Adults receiving care at this free dental hygiene clinic reported generally high levels of oral health literacy as measured by the HeLD-14. No statistically significant differences in OHL were observed by gender, age, or income among the groups studied. These findings suggest that structured, supportive, and educationally rich care environments may help promote OHL among low-income and underserved populations. Equity-focused service delivery may also help reduce knowledge gaps traditionally linked to social determinants of health by emphasizing accessibility, patient education, and trust-building. Integrated, prevention-focused free community dental clinics may therefore represent a promising model for supporting OHL across diverse patient groups.
This study advances the field by providing baseline data on OHL in a specific underserved population. Free clinics can do more than treat disease; they can also empower patients with the knowledge, confidence, and skills needed for long-term oral health success.