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Health Literacy, Dental Service Utilization, and Oral Health Status among High School Students in Hamedan and Saveh, Iran: A Cross-Sectional Study

This cross-sectional study of high school students in Hamedan and Saveh, Iran, reveals that while higher health literacy significantly increases dental service utilization and improves gingival health and oral hygiene, it does not correlate with reduced dental caries, suggesting a need for targeted educational programs to address these specific oral health outcomes.

Original authors: Zahra Rezaei, Alireza Bayat, Samaneh Vaziriamjad, Salman Khazaei, Hojatolah Gharaee

Published 2026-07-30

📖 6 min read🧠 Deep dive

CC BY 4.0

Original authors: Zahra Rezaei, Alireza Bayat, Samaneh Vaziriamjad, Salman Khazaei, Hojatolah Gharaee

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine your mouth as a bustling city. In this city, your teeth are the historic buildings, your gums are the protective parks, and the plaque and tartar are the graffiti and trash that can pile up if no one cleans up. Now, imagine that every citizen in this city has a "User Manual" for keeping the city running smoothly. This manual is called health literacy. It's not just about knowing how to read; it's about understanding how to find good information, figuring out what it means, and actually using it to make smart choices about your health.

But having a manual is only half the battle. You also need to actually go to the city maintenance crew (the dentist) when things get messy. This is called service utilization. Scientists have long wondered: Does having a better User Manual mean you visit the maintenance crew more often? And if you do visit them, does the city actually look cleaner and healthier? This question is especially important for teenagers, a time when hormones and busy schedules can make the city's parks (gums) and buildings (teeth) act up in new ways. If we can figure out how knowledge and visits work together, we might be able to fix the city before it gets too damaged.

The Story of the Teenage City

In this study, researchers from Hamedan University of Medical Sciences decided to investigate this exact scenario. They traveled to the cities of Hamedan and Saveh in Iran to check on the "cities" of 392 high school students. They didn't just ask the students what they thought; they gave them a detailed survey to measure their health literacy (how well they understood and could use health info) and asked them how many times they had visited the dentist in the past year. Then, the researchers put on their detective hats and performed actual clinical exams. They used three specific rulers to measure the health of the students' mouths:

DMFT: A score counting how many teeth were Decayed, Missing, or Filled. Think of this as a "damage report" of the buildings.
CPI: A score for the Community Periodontal Index, which checks the health of the gums (the parks) for bleeding or pockets.
SOHI: A Simplified Oral Hygiene Index, measuring how much debris and tartar (trash) was stuck to the teeth.

What They Found: The Surprising Twist

The results of this investigation were a mix of what you might expect and some surprising twists.

First, the researchers found a clear link between having a good "User Manual" and actually going to the dentist. Students with higher health literacy visited dental services more often. It's like having a better map makes you more likely to drive to the repair shop. In fact, the study showed a strong, direct connection: as health literacy went up, the number of dental visits went up too.

However, when they looked at the actual health of the teeth and gums, the story got a bit more complicated.

The Gums and the Trash (CPI and SOHI):
Here, the User Manual worked perfectly. Students with higher health literacy had healthier gums and less trash on their teeth. The study found a strong inverse relationship: the smarter the students were about oral health, the lower their gum disease scores (CPI) and the cleaner their teeth (SOHI). It seems that knowing how to clean and care for your mouth directly translates to a cleaner city.

The Damage Report (DMFT):
This is where the plot thickens. The study found no significant link between health literacy and the DMFT index (the count of decayed, missing, or filled teeth). Even students with high health literacy had the same number of cavities and fillings as those with lower literacy. The researchers suggest this might be because the DMFT score is a "history book." It counts damage that happened in the past, perhaps before the student even learned how to read their User Manual. If a cavity formed years ago, knowing how to prevent it today won't change the fact that the building is already damaged.

The Visit Paradox:
Perhaps the most interesting finding was about the visits themselves. The study found that students who visited the dentist more often actually had higher DMFT scores (more fillings and missing teeth). This sounds backwards, right? Usually, we think visiting the doctor makes you healthier. But the researchers explained that in this context, frequent visits often meant the students were going for repairs (fillings) rather than prevention. It's like a city where the maintenance crew is only called when the buildings are already crumbling. The visits fixed the immediate problems (filling the holes), which increased the "Filled" part of the DMFT score, but didn't necessarily stop the decay from happening in the first place.

Interestingly, visiting the dentist more often did not show a significant link to improving gum health (CPI) or removing the trash on teeth (SOHI). While the students with higher health literacy had better gums and cleaner teeth, simply going to the dentist more often didn't automatically translate to lower CPI or SOHI scores in this group. This suggests that while visits are important, they might not be enough on their own to improve these specific indices if the visits are focused on treating existing problems rather than daily prevention and hygiene habits.

The Takeaway

So, what does this all mean for our teenage city? The study suggests that while knowing how to care for your mouth (health literacy) is fantastic for keeping your gums healthy and your teeth clean of trash, it doesn't instantly erase the damage of the past. Furthermore, just going to the dentist often doesn't automatically mean your teeth are "cavity-free" or your gums are healthier if those visits are mostly for fixing problems that have already happened.

The authors conclude that to truly improve the health of these teenage cities, we need to do two things: keep teaching students how to be their own best caretakers (boosting health literacy) and make sure they visit the dentist for prevention before the damage starts, not just for repairs after the buildings are already broken. By combining better knowledge with smarter timing for visits, we might finally see a city where the buildings stay standing and the parks stay green.

Technical Summary: Health Literacy, Dental Service Utilization, and Oral Health Status among High School Students in Hamedan and Saveh, Iran

Problem Statement
Oral and dental diseases constitute a significant global health burden, with data indicating that while Decayed, Missing, and Filled Teeth (DMFT) indices have declined globally, the oral health status of children and adolescents in Iran remains unsatisfactory. Specifically, the DMFT among Iranian high school students is reported to be twice the global standard. While the utilization of dental services is a known determinant of oral health, the specific interplay between health literacy (the ability to obtain, process, and understand health information), service utilization, and clinical oral health outcomes in Iranian adolescents remains under-investigated. This study addresses the need to understand how health literacy influences both the frequency of dental service use and the clinical status of oral health (caries, periodontal health, and hygiene) in high school students.

Methodology
This research employed a descriptive-analytical, cross-sectional design conducted in the fall of 2024 among high school students in Hamedan and Saveh, Iran.

Sampling: A multi-stage cluster sampling method was used. Schools were selected from two districts in each city, and classes were randomly chosen from each grade level. The final sample consisted of 392 students.
Inclusion/Exclusion: Participants were enrolled in upper secondary school and willing to participate. Students with systemic diseases or those undergoing orthodontic treatment were excluded.
Data Collection Instruments:
- Health Literacy: Assessed using the validated Adolescent Health Literacy Measurement Tool (44 items across 8 domains: Access, Reading, Comprehension, Evaluation, Application, Communication, Self-Efficacy, and Calculation).
- Service Utilization: Measured by the frequency of various dental services (examinations, fillings, scaling, etc.) utilized in the past year via self-report.
- Clinical Oral Health Status: Evaluated by researchers using WHO protocols and specific indices:
  - DMFT Index: For dental caries (Decayed, Missing, Filled Teeth).
  - CPI Index (Community Periodontal Index): For gingival health and periodontal disease status.
  - SOHI Index (Simplified Oral Hygiene Index): For oral hygiene (debris and calculus).
Statistical Analysis: Data were analyzed using SPSS. Descriptive statistics (means, standard deviations) were calculated. Pearson's correlation coefficients were used to determine relationships between health literacy, service utilization, and clinical indices. Independent t-tests and ANOVA were used for demographic comparisons.

Key Results

Demographics: The majority of participants were male (62.2%) and in the 9th grade (65.8%). Most parents held a high school diploma, and the majority of mothers were housewives.
Descriptive Statistics:
- Mean Health Literacy score: 3.52 (SD 0.625).
- Mean Dental Service Utilization: 4.57 visits (SD 6.645) over the past year.
- Mean Clinical Indices: DMFT (2.36), CPI (1.77), and SOHI (1.32).
Correlations:
- Health Literacy vs. Utilization: A significant direct positive correlation was found ( $r = 0.293, P < 0.001$ ). Higher health literacy was associated with increased utilization of dental services. All eight domains of health literacy showed significant positive correlations with utilization.
- Health Literacy vs. Oral Health Status:
  - DMFT: No significant relationship was found between health literacy and the DMFT index ( $P > 0.05$ ).
  - CPI: A significant inverse relationship was observed ( $r = -0.620, P < 0.001$ ), indicating that higher health literacy correlates with better gingival health (lower CPI scores).
  - SOHI: A significant inverse relationship was observed ( $r = -0.152, P = 0.003$ ), indicating that higher health literacy correlates with better oral hygiene (lower SOHI scores).
- Utilization vs. Oral Health Status:
  - DMFT: A significant direct positive correlation was found ( $r = 0.304, P < 0.001$ ). Increased service utilization was associated with higher DMFT scores.
  - CPI: A significant inverse relationship was found ( $r = -0.434, P < 0.001$ ).
  - SOHI: No significant relationship was found between service utilization and SOHI ( $P > 0.05$ ).

Key Contributions and Claims
The study contributes to the literature by simultaneously examining health literacy, service utilization, and three distinct clinical indices in an Iranian adolescent population.

Differential Impact of Literacy: The authors claim that health literacy acts as a determining factor with a differential role in oral health indices. While it strongly predicts the utilization of services and improves periodontal/hygiene indices (CPI and SOHI), it does not appear to correlate with the cumulative caries experience (DMFT) in this demographic.
Interpretation of Utilization: The paper posits that the positive correlation between service utilization and DMFT likely reflects a "reactive" healthcare model where increased visits are driven by existing disease (fillings and extractions) rather than preventive care. Conversely, the lack of significant improvement in SOHI despite increased utilization suggests that clinical visits alone, without preventive education, do not sufficiently alter daily hygiene behaviors.
Significance: The authors assert that the findings support the hypothesis that greater health literacy encourages active service utilization. However, they emphasize that utilization alone is insufficient for improving oral health status without targeted educational interventions.

Conclusion and Proposed Implications
The paper concludes that while health literacy is a key driver for utilizing dental services, it does not automatically translate to reduced caries (DMFT) in adolescents, possibly due to the cumulative nature of caries or the timing of literacy development relative to disease onset. However, higher literacy is strongly linked to better periodontal and hygiene outcomes.

The authors propose that to improve the oral health status of high school students, educational policies must be redefined. Specifically, they recommend:

Designing targeted educational programs focused on self-care and the prevention of gingival diseases.
Integrating health literacy programs directly into the public education system and school health services.
Shifting the focus from merely increasing service utilization to ensuring that utilization is coupled with preventive and educational interventions.

The study acknowledges limitations, including the reliance on self-reported utilization data (potential recall bias), the exclusion of household income as a variable, and the cross-sectional nature which limits causal inference. Nevertheless, the use of standardized clinical indices and a robust sampling method strengthens the validity of the observed associations.

The Story of the Teenage City

What They Found: The Surprising Twist

The Takeaway

Technical Summary: Health Literacy, Dental Service Utilization, and Oral Health Status among High School Students in Hamedan and Saveh, Iran

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