Assessment of dental students’ knowledge and attitudes regarding passive smoking and its effects on dental health

Abstract

Objective

Passive smoking is also called secondhand smoke (SHS) exposure remains one of the most important yet preventable threats to child health worldwide. Because dentists regularly encounter children and their caregivers, their contribution to household-level tobacco prevention depends on adequate professional training. This study aimed to evaluate dental students’ knowledge and attitudes regarding the oral and dental health consequences of passive smoking, with emphasis on child health and preventive responsibility.

Methods

This cross-sectional study included 748 undergraduate dental students from first to fifth academic year at a public university in Türkiye. Participants completed a structured 16-item questionnaire assessing knowledge of SHS-related systemic and oral health effects, perceived educational sufficiency, and attitudes toward recording SHS exposure during patient anamnesis.

Results

Overall awareness of the harmful effects of passive smoking was high, but significant differences were observed across academic years. Third-year students demonstrated the highest proportion of correct responses, whereas first-year students showed the lowest, and total knowledge scores differed significantly between years (p < 0.001). Although 58.9% of students reported having sufficient knowledge, only a minority had received formal education on SHS, with the lowest rate among second-year students (17.2%). Most students agreed that SHS exposure should be routinely recorded and considered during treatment planning (p < 0.001).

Conclusions

A clear gap exists between general awareness and structured education on SHS. Integrating comprehensive SHS-focused training into undergraduate dental curricula may strengthen child-centred tobacco prevention and enhance the role of dentists in reducing household tobacco exposure.

Introduction

Secondhand smoke (SHS) exposure remains a critical, preventable etiology of pediatric tobacco-related morbidity [1]. Unlike active smoking, SHS is an involuntary environmental hazard dictated by household behaviors and socioeconomic determinants [2]. Globally, hundreds of millions of children are routinely exposed to tobacco smoke, significantly elevating their risk for respiratory pathologies, cardiovascular dysfunction, and adverse neurodevelopmental outcomes [3, 4].

In Türkiye, despite comprehensive public tobacco control legislation, household-level exposure remains pervasive [5]. Evidence indicates that a substantial cohort of school-aged children encounter tobacco smoke in their primary living environments, suggesting that current policies fail to adequately protect the private sphere [6]. This discrepancy underscores the urgent necessity for health-professional–led interventions and family-centric tobacco control [7].

The oral cavity is a primary site of SHS exposure. Tobacco-derived toxins impede enamel mineralization, impair salivary defense mechanisms, and disrupt the oral microbiome. Furthermore, children of smoking parents exhibit earlier colonization by Streptococcus mutans, escalating caries susceptibility [8, 9]. Beyond these effects, SHS is implicated in craniofacial developmental disturbances, including microdontia and hypodontia, as well as Early Childhood Caries (ECC). These biological pathways provide a robust mechanistic foundation for the association between SHS and pediatric oral disease, independent of broader social determinants [8, 10–14].

Given these implications, dental professionals occupy a strategic vantage point to identify household smoking and deliver brief cessation interventions [15]. While previous research has scrutinized dental students’ attitudes toward active tobacco use, there remains a critical gap regarding their specific knowledge of the oral manifestations of SHS, particularly in pediatric populations. This study addresses this unresolved pedagogical gap by evaluating the longitudinal progression of SHS-related knowledge and professional attitudes across all five years of undergraduate dental education. This investigation seeks to determine the extent to which future dentists are prepared to undertake their role in pediatric tobacco prevention and public health advocacy [16, 17]. The primary hypothesis was that knowledge levels regarding the oral effects of SHS would significantly increase with the year of clinical training, yet professional attitudes toward preventive responsibility would remain inconsistent across the curriculum.

Materials and methods

Study design and ethical approval

This cross-sectional study was conducted following approval from the Bülent Ecevit University Clinical Research Ethics Committee (Date: 14 October 2022; Approval No: 2022-22-14/12). Written informed consent was obtained from all participants involved in the study. All participants were informed about the purpose of the study, that their participation was voluntary, and that they could withdraw at any time without penalty. All procedures were carried out in accordance with the Declaration of Helsinki. Participation was voluntary, and students were informed that their academic performance would not be affected by participation. No identifying information was collected, and all responses were analysed anonymously.

Study population and data collection

The study population consisted of all undergraduate dental students enrolled in the Faculty of Dentistry at Bülent Ecevit University. A total of 748 students participated, including 137 first-year, 145 s-year, 175 third-year, 139 fourth-year, and 152 fifth-year students. Data were collected using a self-administered paper questionnaire distributed at the end of scheduled lectures. Completion required approximately 10 min. The 16-item questionnaire was developed based on previous studies evaluating the oral health effects of passive smoking [8, 17, 18].

This study adheres to the standardized reporting protocols for medical surveys, specifically following the recommendations outlined in the relevant consensus-based checklists to enhance the validity and reproducibility of the findings [19]. A prequestionnaire was administered to 10 students from each class, selected at random, to identify comprehension issues and assess whether the questions addressed the research aims. The questionnaire was fine-tuned based on feedback from the pre-questionnaire stage, after which the definitive implementation phase was executed.

Questionnaire structure

The questionnaire comprised three sections using true/false/don’t know and yes/no response formats:

1. Demographic characteristics (year of study and gender);

2. Educational background and attitudes toward passive smoking;

3. Knowledge of the effects of passive smoking on oral and dental health.

Statistical analysis

Completed questionnaires were coded and entered into a database. Analyses were stratified by academic year. Descriptive statistics were reported as number (n), percentage (%), mean, standard deviation (SD), minimum, maximum, and median values. Associations between categorical variables were analysed using the Pearson chi-square test when expected cell counts exceeded five, and Fisher’s exact test otherwise. The Shapiro–Wilk and Levene’s tests were used to assess normality and homogeneity of variance. For comparisons among three or more independent groups with non-normally distributed data, the Kruskal–Wallis test was applied, with Bonferroni correction for post-hoc comparisons. All analyses were performed using IBM SPSS Statistics for Windows, version 25.0 (IBM Corp., Armonk, NY, USA). A p value < 0.05 was considered statistically significant.

Results

A total of 748 dental students participated, yielding a response rate of 100%. The distribution of participants by gender and year of study is presented in Table 1. No statistically significant association was observed between gender and year of study (p > 0.05).

Table 1.

Distribution of students by gender and year of study

Gender	1st year n (%)	2nd year n (%)	3rd year n (%)	4th year n (%)	5th year n (%)	p value
Female	84 (61.3)	93 (64.1)	108 (61.7)	98 (70.5)	98 (64.5)
Male	53 (38.7)	52 (35.9)	67 (38.3)	41 (29.5)	54 (35.5)
Total	137 (100.0)	145 (100.0)	175 (100.0)	139 (100.0)	152 (100.0)	0.497

Values are presented as number (percentage). Pearson chi-square test was used. A p value < 0.05 was considered statistically significant

Students’ knowledge of passive smoking differed significantly by year of study (Table 2). Statistically significant associations were observed for most knowledge items (questions 3 and 5–13; p < 0.05). The highest proportion of correct responses was observed among third-year students, while the lowest was recorded for first-year students. Total knowledge scores also differed significantly across years (p < 0.001), with first-year students presenting the lowest median score. Third- and fourth-year students achieved the highest scores, whereas fifth-year scores were lower than those of the third and fourth years, yet higher than first-year students (Table 3).

Table 2.

Relationship between students’ knowledge of passive smoking and year of study

Question	Correct answer	1st year n (%)	2nd year n (%)	3rd year n (%)	4th year n (%)	5th year n (%)	p value
1. Smoking not only harms the smoker but also affects those exposed to passive smoking in the same environment	True	126 (92.0)	140 (96.6)	172 (98.3)	135 (97.1)	147 (96.7)	0.052
2. Smoking during pregnancy is a risk to the health of the baby	True	128 (93.4)	140 (96.6)	172 (98.3)	137 (98.6)	150 (98.7)	0.065
3. Passive smokers are not affected by cigarette smoke in systemic organs	False	82 (59.9)	102 (70.3)	125 (71.4)	108 (77.7)	114 (75.0)	0.014*
4. Nicotine can easily cross biological membranes	True	64 (46.7)	58 (40.0)	75 (42.9)	56 (40.3)	59 (38.8)	0.677
5. Nicotine does not cross the placental barrier	False	32 (23.4)	50 (34.5)	82 (46.9)	58 (41.7)	56 (36.8)	< 0.001*
6. Maternal smoking increases asthma and wheezing risk in children	True	61 (44.5)	86 (59.3)	142 (81.1)	122 (87.8)	120 (78.9)	< 0.001*
7. Passive smoking causes vascular and coronary damage	True	86 (62.8)	121 (83.4)	159 (90.9)	129 (92.8)	134 (88.2)	< 0.001*
8. Smoking does not affect caries or periodontal disease	False	71 (51.8)	97 (66.9)	99 (56.6)	90 (64.7)	71 (46.7)	< 0.001*
9. There is a negative correlation between passive smoking and caries	False	82 (59.9)	118 (81.4)	143 (81.7)	110 (79.1)	94 (61.8)	0.002*
10. Passive smoking suppresses immunity and increases caries risk	True	59 (43.1)	91 (62.8)	117 (66.9)	105 (75.5)	88 (57.9)	< 0.001*
11. Passive smoking reduces salivary buffering and increases cariogenic bacteria	True	121 (83.4)	134 (88.2)	129 (92.8)	134 (88.2)	134 (88.2)	< 0.001*
12. Passive smoking protects against early S. mutans colonisation	False	40 (29.2)	65 (47.4)	77 (55.4)	62 (40.8)	87 (62.6)	< 0.001*
13. Maternal smoking affects primary and permanent tooth development	True	88 (60.7)	114 (65.1)	113 (64.6)	87 (62.6)		0.006*

Values are presented as number (percentage). Pearson chi-square or Fisher’s exact test was used where appropriate. A p value < 0.05 was considered statistically significant. Statistically significant results are marked with an asterisk

Table 3.

Distribution of total correct answer scores according to year of study

Year of study	n	Minimum	Maximum	Mean ± SD	Median	p value
1st year	137	0	13	8.00 ± 3.08	8
2nd year	145	0	13	9.00 ± 2.76	9
3rd year	175	2	13	10.00 ± 2.71	10
4th year	139	3	13	10.00 ± 2.42	10
5th year	152	0	13	9.00 ± 2.83	9	< 0.001*

Values are presented as number (n), minimum–maximum, mean ± Standard deviation (SD), and median. Kruskal–Wallis test was used. A p value < 0.05 was considered statistically significant

Students’ self-perceived knowledge was significantly associated with the perception of having received sufficient education (p < 0.05). Overall, 58.9% of respondents reported sufficient knowledge, the highest proportion in the third year and the lowest in the fifth year (44.1%). Reported rates of formal education on passive smoking and oral health were low across all years, with the minimum reported by second-year students (17.2%) (Table 4).

Table 4.

Educational background and attitudes of students regarding passive smoking

Question	Response	1st year n (%)	2nd year n (%)	3rd year n (%)	4th year n (%)	5th year n (%)	p value
Do you have sufficient knowledge about the effects of passive smoking on oral and dental health?	No	59 (43.1)	72 (49.7)	72 (41.1)	59 (42.4)	85 (55.9)
	Yes	78 (56.9)	73 (50.3)	103 (58.9)	80 (57.6)	67 (44.1)	0.048*
Have you received sufficient education on this topic?	No	85 (62.0)	120 (82.8)	113 (64.6)	96 (69.1)	106 (69.7)
	Yes	52 (38.0)	25 (17.2)	62 (35.4)	43 (30.9)	46 (30.3)	0.001*
Smoking habits and passive smoking of patients should be recorded in the anamnesis and considered during treatment planning	Agree	94 (68.6)	136 (93.8)	154 (88.0)	128 (92.1)	124 (81.6)
	Disagree	8 (5.8)	0 (0.0)	6 (3.4)	2 (1.4)	7 (4.6)	< 0.001*
	No idea	35 (25.5)	9 (6.2)	15 (8.6)	9 (6.5)	21 (13.8)

Values are presented as number (percentage). Fisher’s exact test was used for all comparisons. A p value < 0.05 was considered statistically significant

The majority of students across all years agreed that smoking habits and passive smoking exposure should be recorded during patient anamnesis and considered during treatment planning (p < 0.001).First-year students were less likely to endorse correct statements than students in higher years.

Discussion

This study provides empirical evidence that while dental students in Türkiye demonstrate a high general awareness regarding the harmful effects of secondhand smoke (SHS), their structured education and detailed scientific understanding of SHS-related oral health risks remain inconsistent across the curriculum. The observed variation in knowledge across academic years offers significant insight into the trajectory of tobacco-related competence acquisition—and its subsequent erosion—during professional dental training [19].

A particularly noteworthy finding is that third- and fourth-year students achieved the highest knowledge scores, whereas final-year students demonstrated a statistically significant decline in performance. This pattern may suggest that SHS-related knowledge is primarily consolidated during the preclinical and early clinical stages, when students are actively engaged with basic biomedical sciences such as pathology, pharmacology, and microbiology. However, as students progress into intensive clinical rotations, the relative salience of preventive tobacco-related content appears to diminish, possibly overshadowed by the demands of procedural and disease-focused clinical training. This trend reflects observations in broader medical and nursing education, where public health competencies have been shown to erode when curricula prioritize clinical interventions over preventive measures [20]. Within the framework of tobacco control, this potential erosion is concerning, as final-year students are at a critical juncture—approaching independent clinical practice where they are most likely to manage pediatric patients and provide caregiver counseling [21, 22].

Our findings align with international literature indicating that while a majority of dental students acknowledge the detrimental health impacts of tobacco exposure, a significant gap exists regarding their confidence and formal training in tobacco-related counseling [23, 24]. For instance, Virtanen et al. reported that a substantial proportion of dental students in Latvia did not fully recognize the specific health risks associated with passive smoking, while Fotedar et al. found that fewer than 10% of dental students had received structured training in smoking cessation strategies [18, 25]. In the present study, although approximately 58.9% of respondents perceived themselves as knowledgeable, only a minority reported receiving formal education on SHS and its implications for oral health. The notably low training rate observed among second-year students (17.2%) could suggest that tobacco-related content is not systematically integrated during the early stages of the curriculum, nor is it consistently reinforced in subsequent years.

This discrepancy between perceived knowledge and documented formal training is particularly relevant from a tobacco control perspective. Knowledge acquired through informal channels—such as general coursework, media exposure, or anecdotal experience—may often remain fragmented or incomplete, potentially failing to translate into evidence-based clinical practice [16]. Without the framework of a structured curriculum, students might not fully appreciate the complex pathophysiological mechanisms through which SHS contributes to oral pathology. These include, but are not limited to, impaired enamel mineralization, altered salivary buffering capacity, immune system modulation, and the promotion of microbial dysbiosis [26]. Such mechanisms are not merely theoretical constructs; they potentially provide the biological foundation for the increased prevalence of dental caries and enamel defects frequently observed in pediatric populations exposed to household tobacco smoke [8, 26, 27].

The high level of agreement among students regarding the necessity of recording SHS exposure during patient anamnesis is encouraging and points toward a developed sense of ethical and professional responsibility. However, international evidence consistently demonstrates that positive attitudes alone are often insufficient to drive tangible behavior change in clinical settings [28]. Studies involving practicing dentists indicate that only a small proportion routinely assess tobacco exposure or provide cessation advice, despite acknowledging its importance [29, 30]. This observed gap between theoretical awareness and clinical implementation is likely influenced by a lack of practical training, diminished professional confidence, and limited institutional support—factors that are frequently rooted in undergraduate dental education.

From a public health perspective, the implications of these findings could be significant [31]. Literature suggests that SHS exposure is often concentrated among socioeconomically disadvantaged populations, where children may simultaneously face a higher risk of poor oral health and reduced access to preventive dental care [31, 32]. In such contexts, dental professionals may serve as one of the few points of professional contact capable of identifying environmental risks and intervening early. Consequently, providing inadequate training to dental students in SHS assessment and counseling has the potential to indirectly sustain existing disparities in pediatric oral health and may undermine broader tobacco control initiatives.

Türkiye’s experience further underscores the critical nature of this issue. Although the country has implemented robust tobacco control legislation in alignment with the WHO Framework Convention on Tobacco Control, household smoking remains relatively widespread, and pediatric populations continue to be exposed at high rates [33]. This situation may indicate that legislative approaches, while necessary, should be ideally complemented by health-professional–led interventions that target family-level behavioral changes. Dentists, when provided with adequate training, could potentially play a pivotal role in this strategy by routinely documenting SHS exposure, educating caregivers, and reinforcing smoke-free home norms [1, 34–36].

The present study has several limitations that warrant consideration. Its cross-sectional design does not allow for definitive causal inferences regarding how knowledge is acquired or lost throughout the duration of professional training. Furthermore, data were obtained from a single institution, which may limit the generalizability of the findings to all dental schools across Türkiye. Additionally, as with many survey-based studies, self-reported responses might have been influenced by social desirability bias. Nevertheless, the substantial sample size, the inclusion of all five academic years, and the 100% response rate provide a significant empirical basis for the trends observed in this cohort.

Conclusion

Although dental students demonstrated a generally high awareness of the harmful effects of passive smoking, substantial deficiencies persist in their formal education and depth of scientific knowledge. Knowledge varied across academic years, with evidence of decline during final-year clinical training. Given children’s vulnerability to involuntary tobacco exposure and its contribution to preventable oral disease and health inequalities, these educational gaps represent a missed opportunity for early prevention. Integrating structured SHS and tobacco control education—together with practical counselling skills—into undergraduate dental curricula may strengthen the role of dentists in child-centred tobacco control and support broader public health goals.

Authors’ contributions

EHB and EBK contributed to the study concept and design. EHB, AA, and AC were involved in data collection. EBK performed the data analysis and interpretation. EHB and EBK drafted the initial manuscript. AA and AC critically revised the manuscript for important intellectual content. All authors read and approved the final manuscript.

Funding

This was a self-funded study.

Data availability

The data that support the findings of this study are available on re-quest from the corresponding author. The data are not publicly avail-able due to privacy or ethical restrictions.

Declarations

Ethics approval and consent to participate

Prior to the commencement of the study, ethical approval was obtained from the Zonguldak Bulent Ecevit University Clinical Research Ethics Committee. The decision was dated 14/10/2022 and numbered 2022-22-14/12. The research was completed in accordance with the Helsinki Declaration.

Competing interests

The authors declare no competing interests.