Abstract
Background
Halitosis, or bad breath, significantly affects social and psychological well-being and is often caused by intraoral factors. Dentists play a key role in the diagnosis and treatment of halitosis, but inadequate education may lead to ineffective patient care. This study examines the levels of knowledge and awareness of halitosis among undergraduate dental students.
Methods
This study employed a cross-sectional design and used an online questionnaire that was developed via Google Forms. The questionnaire was distributed to a convenience sample of 250 undergraduate students from two different dentistry faculties who had completed their clinical internships. All the statistical analyses were performed using SPSS for Windows 11.5 (SPSS Inc., Chicago, IL, USA). Responses to the questionnaire were compared between groups using the Pearson chi-square test or Fisher’s exact test. The correct answer scores were compared between groups via the Mann‒Whitney U test.
Results
There was a significant difference in the degree of attention devoted to halitosis between X University and Y University (p < 0.05). When asked, “Have you ever treated patients with halitosis? “, 28.5% of fourth-year students and 60.5% of fifth-year students answered affirmatively, indicating a statistically significant difference (p < 0.001). There was no significant difference in the number of correct answers between fourth- and fifth-year students (U = 7714.00, p = 0.886). There was a significant difference in the number of correct answers between the universities (U = 5817.50, p = 0.001). The number of correct answers of X University students was slightly higher than that of Y University students.
Conclusions
These results support the importance of developing training programs to improve dentists’ self-confidence, social skills, and communication skills, thereby enhancing the diagnosis and treatment of halitosis. A manual for the diagnosis and treatment of halitosis could be helpful for improving dentists’ attitudes and behaviours and for promoting optimal oral health.
Keywords: Bad breath, Dentistry, Students
Background
The term halitosis is derived from the Latin words “halitus” (breath) and “-osis” (condition) and is used to describe the condition known as bad breath, also referred to as oral malodor, fetor oris, and fetor ex ore [1]. This condition has the potential to significantly impact an individual’s social interactions and self-confidence [2]. Halitosis has been recognized since ancient times, with references to this condition found in ancient Greek and Roman inscriptions and religious texts. For example, it was mentioned in the Jewish Talmud some 2,000 years ago [3]. Additionally, oral hygiene is highly important in the Islamic tradition: the Prophet advised against attending the mosque if one had consumed foods that cause bad odours, such as onions and garlic [4]. Currently, approximately half of the world’s population experiences some degree of halitosis. However, the prevalence of halitosis varies widely across countries and communities, thus reflecting the different methodologies used in epidemiologic studies [5].Halitosis can be divided into three groups: genuine halitosis, pseudohalitosis and halitophobia. Genuine halitosis is further divided into physiological halitosis, such as morning breath, and pathological halitosis, which includes oral causes (e.g. poor oral hygiene or periodontal disease) and extra-oral causes (e.g. systemic conditions such as gastrointestinal or metabolic disorders). Pseudohalitosis refers to cases where individuals perceive that they have bad breath without the presence of objective oral malodour; this condition can often be resolved by dentists through counselling and simple oral hygiene measures. Halitophobia, on the other hand, is a persistent fear of having bad breath in the absence of detectable malodour and usually requires psychological assessment and intervention, as these individuals persist in reporting an unpleasant breath odour despite the implementation of an appropriate treatment plan [6]. A variety of diagnostic techniques are used to identify halitosis. Organoleptic assessment is considered the gold standard diagnostic technique. Other diagnostic methods include gas chromatography and portable devices that measure volatile sulphur compounds (VSCs), such as the Halimeter® [7]. The primary cause of halitosis is the formation of VSCs by anaerobic bacteria in the oral cavity, which are induced by the breakdown of sulphur-containing amino acids. These compounds include hydrogen sulfide and methyl mercaptan, which are the primary components of the malodor associated with halitosis [8]. The most common causes of halitosis are intraoral, including tongue coating, periodontal disease, and poor oral hygiene. These factors account for 80–90% of the cases [9, 10]. Dentists play a pivotal role in the management of halitosis, with the majority of cases attributed to intraoral factors. Dentists address this condition by providing professional cleaning services and encouraging optimal oral hygiene practices. Bad breath is a common reason for patients to seek dental care [11]. Even people without clinically diagnosed halitosis may be interested in methods to reduce their breath odour. Recent reviews have highlighted the need for health professionals to increase their awareness of halitosis [9, 12]. The implementation of improvements in this area depends on addressing the challenges inherent in the educational process. Inadequate training can lead to a lack of confidence among dentists and an inadequate response to patients’ needs. Dentists who have not received adequate training in this area may lack the necessary skills to effectively diagnose and treat halitosis [13]. The purpose of this study was to evaluate dental students’ knowledge and awareness of halitosis and its treatment in order to identify possible deficiencies in existing educational programs.
Methods
This anonymous, multinational, cross-sectional survey study was designed and conducted in accordance with the Checklist for Reporting Results of Internet E-Surveys (CHERRIES), which is a standardized checklist for reporting the design, conduct, and results of Internet-based surveys to ensure transparency and reproducibility [14]. In this study, ‘awareness’ refers to the students’ recognition of and attentiveness to halitosis during clinical encounters, whereas ‘knowledge’ encompasses their understanding of the causes, diagnosis, and treatment of halitosis.
Study design and ethical approval
This study was conducted in accordance with the ethical standards outlined in the Declaration of Helsinki and approved by the Non-Interventional Clinical Research Ethics Committee of Uşak University (Approval No: 55-55-09). All participants provided informed consent prior to participation.
Sample and recruitment process
The duration of education in dental schools in Turkey is five years. The last two years of the curriculum include clinical training. Therefore, the study group was selected from fourth- and fifth-year students. A convenience sample of 250 fourth- and fifth-year undergraduate dental students from two universities was targeted. Students were invited to participate through an email that distributed the survey link exclusively via the universities’ internal communication platforms, ensuring a closed survey design limited to the target group. Participation was voluntary, and the survey was administered anonymously to protect participant confidentiality. Informed consent was obtained electronically. The participants received a detailed explanation of the purpose, procedures, risks, and benefits of the study before proceeding. They had to give explicit consent to continue. Not all the participants answered every question; therefore, each question had to be scored based on the number of respondents who answered it.
Questionnaire development and pretesting
The questionnaire items were inspired by Buunk-Werkhoven’s publication [15]. Before the study began, we sent an open letter to the author of the original study requesting permission to use the questionnaire. The questionnaire was translated in accordance with the guidelines outlined by Del Greco, Walop, and Eastridge [16].Initially, the questionnaire was translated into Turkish by bilingual experts. Then, back-translation was performed by a different expert to ensure that the meaning of the original questionnaire was accurately conveyed in Turkish. The original and back-translated versions were compared, and any discrepancies were evaluated and corrected. This process ensured that the translation was culturally and linguistically appropriate. Final questionnaire included questions designed to evaluate awareness (such as whether students routinely consider halitosis during patient assessments) and knowledge assessed through true/false statements related to the aetiology and management of the condition). It consisted of 13 items across five domains: attention to halitosis, experience with halitosis patients, referral practices, treatment protocols, and educational resources. The first 12 items were direct questions, whereas the 13th item required participants to assess statements as “true” or “false.” A pre-test was conducted with 20 dental students, consisting of 10 students from University X (5 fourth-year and 5 fifth-year students) and 10 students from University Y (5 fourth-year and 5 fifth-year students), to ensure the comprehensibility of the survey. Minor adjustments were made based on their feedback.
Survey administration
The survey was administered using Google Forms, and the participants were given one week to complete the questionnaire. The survey was available in Turkish, and all participants were confirmed to be proficient in the language. The online format allowed for broad and flexible distribution, ensuring easy access for participants. The survey was divided into four pages: the first page contained four questions, the second page had four questions, the third page included four questions, and the fourth page consisted of 12 statements to be evaluated as true or false. This distribution was designed to balance the presentation of material and minimize respondent fatigue.
Data collection
The data were collected using a structured online questionnaire administered via Google Forms. The participants were recruited from two universities, and the questionnaire link was distributed through internal communication channels. Responses were collected over a period of two weeks, and participation was voluntary. The questionnaire consisted of sections assessing both awareness and knowledge of halitosis, including 12 true/false knowledge-based items.
Data analysis
After data collection, the responses were exported from Google Forms and analysed using Statistical Package for the Social Sciences for Windows 11.5 (SPSS Inc., Chicago, IL, USA). Continuous variables were assessed for normality via the Kolmogorov‒Smirnov test. Categorical variables were summarized using frequencies and percentages. Descriptive statistics were used to summarize the demographic characteristics of the participants.
All continuous variables in this study were not normally distributed. Since they were not normally distributed, continuous variables were expressed as medians (minimum-maximum). Differences between the groups’ responses to the questions were examined using the Pearson chi-square test or Fisher’s exact test, where appropriate, for categorical variables. For continuous variables, the number of correct answers (for the 12 true/false questions) between groups was analysed using the Mann‒Whitney U test. A p value ≤ 0.05 was considered statistically significant.
Data protection and confidentiality
The survey was anonymous, and no identifying information was collected from the participants. The data were securely stored and accessible only to the research team. All procedures adhered to ethical guidelines for human subject research, ensuring participant confidentiality and data integrity.
Results
A total of 250 students participated in the study, of whom 172 (68.8%) were female and 78 (31.2%) were male. The participants were almost evenly distributed between the 4th and 5th academic years, with 131 (52.4%) students in the 4th year and 119 (47.6%) in the 5th year. In terms of university affiliation, the majority of the students were from X University (142 students, 56.8%), whereas the remaining 108 (43.2%) were from Y University (Table 1).
Table 1.
The demographic and academic characteristics of students
| Demographic and Academic Characteristics (n(%)) | |
|---|---|
| n = 250 | |
| Gender | |
| Female | 172 (68.8%) |
| Male | 78 (31.2%) |
| Class | |
| 4th | 131 (52.4%) |
| 5th | 119 (47.6%) |
| University | |
| X | 142 (56.8%) |
| Y | 108 (43.2%) |
The level of attention to halitosis was significantly greater among fifth-year students than among fourth-year students during patient contact (p < 0.001). In addition, the proportion of Y University students who answered “never” to this question was significantly greater than that of X University students (p = 0.001). A discrepancy was observed between the responses of fourth- and fifth-year students to the following question: “Do you consider halitosis in the dental history?” (p < 0.001). The answer “never” was chosen by 22.9% of fourth-year students and 10.9% of fifth-year students. A significant difference was observed between students at X and Y universities, with 2.1% of X University students and 10.2% of Y University students answering “always” to this question (p < 0.001) (Table 2).
Table 2.
Attention to halitosis by fourth- and fifth-year undergraduate dental students at X and Y universities
| Questions | Students | Universities | ||||
|---|---|---|---|---|---|---|
| Fourth Year | Fifth Year | p value | X | Y | p value | |
| 1. Are you attentive to halitosis during patient contacts? | ||||||
| Never | 14 (10.7%)a | 0 (0.0%)b | < 0.001 | 3 (2.1%)a | 11 (10.2%)b | 0.001 |
| Mostly not | 30 (22.9%)a | 5 (4.2%)b | 12 (8.5%)a | 23 (21.3%)b | ||
| Now and then | 64 (48.9%)a | 60 (50.4%)a | 79 (56.0%)a | 45 (41.7%)b | ||
| Usually | 18 (13.7%)a | 44 (37.0%)b | 37 (26.2%)a | 24 (22.2%)a | ||
| Always | 5 (3.8%)a | 10 (8.4%)a | 10 (7.1%)a | 5 (4.6%)a | ||
| Total | 131 (100.0%) | 119 (100.0%) | 141 (100.0%) | 108 (100.0%) | ||
| 2. Do you tell a patient that he/she has bad breath? | ||||||
| Never | 36 (27.5%) | 27 (22.9%) | 0.419 | 30 (21.3%)a | 33 (30.8%)a | 0.002 |
| Mostly not | 33 (25.2%) | 33 (28.0%) | 36 (25.5%)a | 29 (27.1%)a | ||
| Now and then | 41 (31.3%) | 46 (39.0%) | 62 (44.0%)a | 25 (23.4%)b | ||
| Usually | 15 (11.5%) | 7 (5.9%) | 11 (7.8%)a | 11 (10.3%)a | ||
| Always | 6 (4.6%) | 5 (4.2%) | 2 (1.4%)a | 9 (8.4%)b | ||
| Total | 131 (100.0%) | 118 (100.0%) | 141 (100.0%) | 107 (100.0%) | ||
| 3. Do you attend to halitosis in the dental anamnesis? | ||||||
| Never | 30 (22.9%)a | 13 (10.9%)b | < 0.001 | 24 (17.0%)a | 18 (16.7%)a | < 0.001 |
| Mostly not | 37 (28.2%)a | 33 (27.7%)a | 57 (40.4%)a | 13 (12.0%)b | ||
| Now and then | 29 (22.1%)a | 55 (46.2%)b | 42 (29.8%)a | 42 (38.9%)a | ||
| Usually | 25 (19.1%)a | 14 (11.8%)a | 15 (10.6%)a | 24 (22.2%)b | ||
| Always | 10 (7.6%)a | 4 (3.4%)a | 3 (2.1%)a | 11 (10.2%)b | ||
| Total | 131 (100.0%) | 119 (100.0%) | 141 (%100.0%) | 108 (%100.0) | ||
Superscripts (a, b) in the tables denote groups that are significantly different from each other based on post hoc tests with Bonferroni correction
In terms of clinical experience, 28.5% of fourth-year students reported having treated patients with halitosis, whereas this rate was 60.5% for fifth-year students; this difference was statistically significant (p < 0.001). However, there was no statistically significant difference between universities regarding this question (p = 0.069), although the trend suggests a potential difference that may warrant further investigation with a larger sample size.
A statistically significant difference was found in the number of patients treated in the past six months between year groups and universities (p < 0.001). Among fourth-year students, 58.0% treated fewer than 5 patients, whereas 34.8% of fifth-year students treated more than 15 patients. At X University, 43.1% of the students treated more than 15 patients, whereas only 3.8% at Y University treated more than 15 patients. Conversely, 43.8% of the students at Y University treated fewer than 5 patients, whereas 38.0% at X University treated fewer than 5 patients (Table 3).
Table 3.
Treatment of patients with halitosis by dentistry students in the two schools
| Questions | Students | Universities | ||||
|---|---|---|---|---|---|---|
| Fourth Year | Fifth Year | p value | X | Y | p value | |
| 4. Have you ever treated patients with halitosis? | ||||||
| Yes | 37 (28.5%)a | 72 (60.5%)b | < 0.001 | 68 (48.6%) | 40 (37.0%) | 0.069 |
| No | 93 (71.5%)a | 47 (39.5%)b | 72 (51.4%) | 68 (63.0%) | ||
| Total | 130 (100.0%) | 119 (100,0%) | 140 (100,0%) | 108 (100,0%) | ||
| 5. How many patients with halitosis did you treat in the past six months? | ||||||
| < 5 | 76 (58.0%)a | 23 (20.5%)b | < 0.001 | 52 (38.0%)a | 46 (43.8%)a | < 0.001 |
| 5–10 | 29 (22.1%)a | 29 (25.9%)a | 21 (15.3%)a | 37 (35.2%)b | ||
| 11–15 | 2 (1.5%)a | 21 (18.8%)b | 5 (3.6%)a | 18 (17.1%)b | ||
| > 15 | 24 (18.3%)a | 39 (34.8%)b | 59 (43.1%)a | 4 (3.8%)b | ||
| Total | 131 (100.0%) | 112 (100.0%) | 137 (100.0%) | 105 (100.0%) | ||
Superscripts (a, b) in the tables denote groups that are significantly different from each other based on post hoc tests with Bonferroni correction
When examining the referrals of halitosis patients, a significant difference was observed between fourth- and fifth-year students (p = 0.002) and between universities (p = 0.002) in response to the question “Have you ever referred a patient for treatment of halitosis?” Fifth-year students (34.2%) and students at X University (32.6%) were more likely to have referred a patient than fourth-year students (16.9%) and Y University students (15.7%). While no significant difference was found in the reasons for referral between year groups (p = 0.901) or universities (p = 0.221), the most common reason for referral in both groups was “I did not know how to treat the patient.” There was a significant difference between universities in response to “To whom do you usually refer?” Compared with Y University students, X University students were more likely to refer patients to a halitosis office. (p = 0.033) No significant difference was found in the reasons for not referring patients between year groups (p = 0.592) or universities (p = 1.000), with the most common reason being unfamiliarity with referral options. (Table 4)
Table 4.
Referral of patients with halitosis by fourth- and fifth-year students from two different dental schools
| Questions | Students | Universities | ||||
|---|---|---|---|---|---|---|
| Fourth Year | Fifth Year | p value | X | Y | p value | |
| 6. Have you ever referred a patient for treatment of halitosis? | ||||||
| Yes | 22 (16.9%)a | 40 (34.2%)b | 0.002 | 45 (32.6%)a | 17 (15.7%)b | 0.002 |
| No | 108 (83.1%)a | 77 (65.8%)b | 93 (67.4%)a | 91 (84.3%)b | ||
| Total | 130 (100.0%) | 117 (100.0%) | 138 (100.0%) | 108 (100.0%) | ||
| 7. What was/were the reason for referral? | ||||||
| Patient had a form of extraoral halitosis | 20 (36.4%) | 18 (36.0%) | 0.901 | 23 (30.3%) | 15 (51.7%) | 0.221 |
| I did not know how to treat the patient | 28 (50.9%) | 26 (52.0%) | 42 (55.3%) | 12 (41.4%) | ||
| My treatment did not succeed | 5 (9.1%) | 3 (6.0%) | 7 (9.2%) | 1 (3.4%) | ||
| Different reason | 2 (3.6%) | 3 (6.0%) | 4 (5.3%) | 1 (3.4%) | ||
| Total | 55 (100.0%) | 50 (100.0%) | 76 (100.0%) | 29 (100.0%) | ||
| 8. To whom do you usually refer? | ||||||
| A specialist outside the dental profession | 9 (8.4%) | 11 (11.3%) | 0.518 | 12 (9.5%)a | 8 (10.4%)a | 0.033 |
| A halitosis office hour within or without the practice | 71 (66.4%) | 57 (58.8%) | 87 (69.0%)a | 40 (51.9%)b | ||
| Different | 27 (25.2%) | 29 (29.9%) | 27 (21.4%)a | 29 (37.7%)b | ||
| Total | 107 (100.0%) | 97 (100.0%) | 126 (100.0%) | 77 (100.0%) | ||
| 9. What is the most important reason for not referring? | ||||||
| I do not treat halitosis patients | 17 (23.3%) | 12 (14.8%) | 0.592 | 17 (18.5%) | 12 (19.4%) | 1.000 |
| I am not acquainted with the possibilities for referral | 46 (63.0%) | 55 (67.9%) | 60 (65.2%) | 41 (66.1%) | ||
| I can treat halitosis patients myself | 9 (12.3%) | 12 (14.8%) | 13 (14.1%) | 8 (12.9%) | ||
| Different reason | 1 (1.4%) | 2 (2.5%) | 2 (2.2%) | 1 (1.6%) | ||
| Total | 73 (100.0%) | 81 (100.0%) | 92 (100.0%) | 62 (100.0%) | ||
Superscripts (a, b) in the tables denote groups that are significantly different from each other based on post hoc tests with Bonferroni correction
Regarding treatment protocols, no significant difference was found between fourth- and fifth-year students or between universities in their responses to the question “Is there a treatment protocol in the practice?” (p = 0.667 and p = 0.673, respectively) (Table 5). However, a discrepancy was found between the responses of students from X and Y Universities to the question “Would you find the presence of a treatment protocol useful?” with a statistically significant difference (p < 0.001). Among the students, 34.1% of the students from X University and 60.6% of the students from Y University found the presence of a treatment protocol useful (Table 5).
Table 5.
Presence of a treatment protocol for patients with halitosis
| Questions | Students | Universities | ||||
|---|---|---|---|---|---|---|
| Fourth Year | Fifth Year | p value | X | Y | p value | |
| 10. Is a treatment protocol present in the practice? | ||||||
| Yes | 39 (30.2%) | 39 (32.8%) | 0.667 | 43 (30.5%) | 35 (33.0%) | 0.673 |
| No | 90 (69.8%) | 80 (67.2%) | 98 (69.5%) | 71 (67.0%) | ||
| Total | 129 (100.0%) | 119 (100.0%) | 141 (100.0%) | 106 (100.0%) | ||
| 11. Would you find the presence of a treatment protocol useful? | ||||||
| Yes | 40 (38.8%) | 45 (48.9%) | 0.157 | 42 (34.1%)a | 43 (60.6%)b | < 0.001 |
| No | 63 (61.2%) | 47 (51.1%) | 81 (65.9%)a | 28 (39.4%)b | ||
| Total | 103 (100.0%) | 92 (100.0%) | 123 (100.0%) | 71 (100.0%) | ||
Superscripts (a, b) in the tables denote groups that are significantly different from each other based on post hoc tests with Bonferroni correction
In terms of educational resources, a significant difference was observed between fourth- and fifth-year students in terms of how they obtained information (p = 0.002). A total of 75% of fourth-year students and 51.3% of fifth-year students reported that they acquired their knowledge through education. There was no significant difference (p = 0.229) between universities in terms of the methods by which students acquired information (Table 6). A gender difference was observed in the responses to the question “How did you acquire your knowledge? A significantly higher proportion of men reported gaining knowledge through literature and consultation (p < 0.001).
Table 6.
Ways in which two dentistry school students have acquired knowledge of halitosis
| Questions | Students | University | ||||
|---|---|---|---|---|---|---|
| Fourth Year | Fifth Year | p value | X | Y | p value | |
| 12. In which way(s) have you acquired your knowledge? | 0.002 | 0.229 | ||||
| By education | 96 (75.0%)a | 60 (51.3%)b | 83 (60.1%) | 72 (67.9%) | ||
| Through literature | 5 (3.9%)a | 6 (5.1%)a | 7 (5.1%) | 4 (3.8%) | ||
| By peer contracts/peer consultation | 3 (2.3%)a | 4 (3.4%)a | 5 (3.6%) | 2 (1.9%) | ||
| By continuing vocational training | 5 (3.9%)a | 8 (6.8%)a | 11 (8.0%) | 2 (1.9%) | ||
| Through information from the professional organization | - | - | - | - | ||
| Through information from commerce | - | - | - | - | ||
| Number of mentioned knowledge sources | 19 (14.8%)a | 39 (33.3%)b | 32 (23.2%) | 26 (24.5%) | ||
| Total | 128 (100.0%) | 117 (100.0%) | 138 (100.0%) | 106 (100.0%) | ||
Superscripts (a, b) in the tables denote groups that are significantly different from each other based on post hoc tests with Bonferroni correction
In terms of individual knowledge, there was no significant difference between fourth- and fifth-year students in terms of the number of correct answers (U = 7714.00, p = 0.886). The median (min–max) number of correct answers was 6.00 (1.00–10.00) for fourth-year students and 6.00 (3.00–10.00) for fifth-year students. There was a significant difference in the number of correct answers between the universities (U = 5817.50, p = 0.001). The median (minimum-maximum) number of correct answers was 6.50 (4.00–10.00) for X University and 6.00 (1.00–9.00) for Y University. The number of correct answers of X University students was slightly greater than that of Y University students. The percentages of correct responses of the students of the Faculty of Dentistry to a number of statements about halitosis are shown in Table 7.
Table 7.
Percentage of correct responses of undergraduate dental students to a series of statements about halitosis (a, e, j, and l are correct statements)
| Statements | X Fourth Year | Y Fourth Year | Total | X Fifth Year | Y Fifth Year | Total |
|---|---|---|---|---|---|---|
| a) In cases of halitosis, the bad smell can come from the mouth as well as the nose | ||||||
| True | 59 (77.6%) | 34 (61.8%) | 93 (71.0%) | 51 (77.3%) | 35 (66.0%) | 86 (72.3%) |
| False | 17 (22.4%) | 21 (38.2%) | 38 (29.0%) | 15 (22.7%) | 18 (34.0%) | 33 (27.7%) |
| Total | 76 (100.0%) | 55 (100.0%) | 131 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| b) Pseudo-halitosis is the initial stage of pathological halitosis | ||||||
| True | 31 (41.3%) | 24 (48.0%) | 55 (44.0%) | 24 (36.4%) | 30 (58.8%) | 54 (46.2%) |
| False | 44 (58.7%) | 26 (52.0%) | 70 (56.0%) | 42 (63.6%) | 21 (41.2%) | 63 (53.8%) |
| Total | 75 (100.0%) | 50 (100.0%) | 125 (100.0%) | 66 (100.0%) | 51 (100.0%) | 117 (100.0%) |
| c) Extraoral halitosis is a variant of physiological halitosis | ||||||
| True | 63 (82.9%) | 40 (83.3%) | 103 (83.1%) | 58 (87.9%) | 42 (80.8%) | 100 (84.7%) |
| False | 13 (17.1%) | 8 (16.7%) | 21 (16.9%) | 8 (12.1%) | 10 (19.2%) | 18 (15.3%) |
| Total | 76 (100.0%) | 48 (100.0%) | 124 (100.0%) | 66 (100.0%) | 52 (100.0%) | 118 (100.0%) |
| d) A bad smell has always to do with poor oral hygiene | ||||||
| True | 5 (6.6%) | 2 (3.6%) | 7 (5.3%) | 7 (10.6%) | 6 (11.3%) | 13 (10.9%) |
| False | 71 (93.4%) | 53 (96.4%) | 124 (94.7%) | 59 (89.4%) | 47 (88.7%) | 106 (89.1%) |
| Total | 76 (100.0%) | 55 (100.0%) | 131 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| e) Mostly a bad morning breath disappears after toothbrushing or having breakfast | ||||||
| True | 76 (100%) | 53 (98.1%) | 129 (99.2%) | 64 (97.0%) | 53 (100.0%) | 117 (98.3%) |
| False | - | 1 (1.9%) | 1 (0.8%) | 2 (3.0%) | - | 2 (1.7%) |
| Total | 76 (100.0%) | 54 (100.0%) | 130 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| f) The remedy for extra-oral halitosis is the use of tongue scraper and/or the use of a mouth rinse | ||||||
| True | 53 (71.6%) | 37 (71.2%) | 90 (71.4%) | 36 (54.5%) | 38 (71.7%) | 74 (62.2%) |
| False | 21 (28.4%) | 15 (28.8%) | 36 (28.6%) | 30 (45.5%) | 15 (28.3%) | 45 (37.8%) |
| Total | 74 (100.0%) | 52 (100.0%) | 126 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| g) A bad taste in the mouth goes together with bad breath | ||||||
| True | 68 (89.5%) | 45 (83.3%) | 113 (86.9%) | 63 (95.5%) | 48 (90.6%) | 111 (93.3%) |
| False | 8 (10.5%) | 9 (16.7%) | 17 (13.1%) | 3 (4.5%) | 5 (9.4%) | 8 (6.7%) |
| Total | 76 (100.0%) | 54 (100.0%) | 130 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| h) A patient can well conceive if he/she has a bad breath | ||||||
| True | 64 (84.2%) | 46 (83.6%) | 110 (84.0%) | 58 (87.9%) | 41 (77.4%) | 99 (83.2%) |
| False | 12 (15.8%) | 9 (16.4%) | 21 (16.0%) | 8 (12.1%) | 12 (22.6%) | 20 (16.8%) |
| Total | 76 (100.0%) | 55 (100.0%) | 131 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| i) Performing an organoleptic measurement requires wearing a mouth cap | ||||||
| True | 23 (32.4%) | 28 (57.1%) | 51 (42.5%) | 19 (28.8%) | 31 (72.1%) | 50 (45.9%) |
| False | 48 (67.6%) | 21 (42.9%) | 69 (57.5%) | 47 (71.2%) | 12 (27.9%) | 59 (54.1%) |
| Total | 71 (100.0%) | 49 (100.0%) | 120 (100.0%) | 66 (100.0%) | 43 (100.0%) | 109 (100.0%) |
| j) If a patient suffers from halitophobia, referral to a psychologist is indicated | ||||||
| True | 58 (76.3%) | 40 (75.5%) | 98 (76.0%) | 56 (84.8%) | 31 (58.5%) | 87 (73.1%) |
| False | 18 (23.7%) | 13 (24.5%) | 31 (24.0%) | 10 (15.2%) | 22 (41.5%) | 32 (26.9%) |
| Total | 76 (100.0%) | 53 (100.0%) | 129 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| k) When halitosis has an extraoral cause, referral to a gastrointestinal specialist is indicated | ||||||
| True | 68 (89.5%) | 40 (72.7%) | 108 (82.4%) | 57 (90.5%) | 40 (75.5%) | 97 (83.6%) |
| False | 8 (10.5%) | 15 (27.3%) | 23 (17.6%) | 6 (9.5%) | 13 (24.5%) | 19 (16.4%) |
| Total | 76 (100.0%) | 55 (100.0%) | 131 (100.0%) | 63 (100.0%) | 53 (100.0%) | 116 (100.0%) |
| l) When uncertainty about the presence and/or origin of halitosis exists, referral of a patient for diagnosis to halitosis office hour is indicated | ||||||
| True | 74 (97.4%) | 47 (85.5%) | 121 (92.4%) | 64 (97.0%) | 48 (90.6%) | 112 (94.1%) |
| False | 2 (2.6%) | 8 (14.5%) | 10 (7.6%) | 2 (3.0%) | 5 (9.4%) | 7 (5.9%) |
| Total | 76 (100.0%) | 55 (100.0%) | 131 (100.0%) | 66 (100.0%) | 53 (100.0%) | 119 (100.0%) |
| Number of correct answers (Median-min/max) | (n = 76) | (n = 55) | (n = 131) | (n = 66) | (n = 53) | (n = 119) |
| 6 (4–10) | 6 (1–9) | 6 (1–10) | 7 (4–10) | 6 (3–9) | 6 (3–10) |
The statement “Mostly a bad morning breath disappears after toothbrushing or having breakfast” (e) received the highest number of correct answers from both universities. At X University, 100% of fourth-year students and 97.0% of fifth-year students responded correctly, whereas at Y University, 98.1% of fourth-year students and 100% of fifth-year students answered correctly.
Similarly, for the statement “When uncertainty about the presence and/or origin of halitosis exists, referral of a patient for diagnosis to halitosis office hour is indicated” (l), the majority of students provided correct answers. At X University, 97.4% of fourth-year students and 97.0% of fifth-year students answered correctly, whereas at Y University, 85.5% of fourth-year students and 90.6% of fifth-year students responded correctly.
The statement “A bad taste in the mouth goes together with bad breath” (g) had the lowest number of correct responses. At X University, only 10.5% of fourth-year students and 4.5% of fifth-year students answered correctly, whereas at Y University, 16.7% of fourth-year students and 9.4% of fifth-year students provided correct answers.
Another question with low correct responses was “When halitosis has an extraoral cause, referral to a gastrointestinal specialist is indicated” (k). At X University, only 10.5% of fourth-year students and 9.5% of fifth-year students answered correctly, whereas at Y University, 27.3% of fourth-year students and 24.5% of fifth-year students responded correctly.
Discussion
Bad breath is a common problem among the general population. It can be embarrassing and can interfere with socialization, creating a social handicap. Given the potential social consequences of halitosis, it is imperative that oral health professionals provide patients with comprehensive education regarding the presence of halitosis. It is imperative that they are adequately prepared to practice in a sensitive and appropriate manner with the goal of improving the oral health-related quality of life and well-being of patients. The purpose of this study was to determine the knowledge base of undergraduate dental students regarding halitosis and the manner in which they manage patients presenting with this condition.
Halitosis is a recognizable disease that requires professional intervention [17]. To diagnose this disease, dental schools must commit to ensuring that their students are particularly aware of it. The responses to the questions in the first section of the data sheet indicate that halitosis is not a routine element of patient communication during dental procedures. However, fifth-year students and students from X University paid more attention to this issue. It is evident that students are reluctant to inform patients about their halitosis. These findings are in alignment with those of a previous study utilising the same questionnaire, wherein it was observed that dentists exhibited similar attitudes [15]. This may be due to dentists’ concerns that disclosing unfavourable information to patients may cause feelings of shame or embarrassment. Research has shown that halitosis is one of the most significant “disappointments” in social interactions [18]. A 2009 Italian study revealed that approximately one-third of people who received feedback about bad breath from people around them had previously undergone a dental examination but were not informed [19].This suggests that dentists may avoid discussing bad breath, even if the patient has bad breath. It is crucial to implement a dental anamnesis form that emphasises attention to halitosis during clinical internships, where habits related to patient communication are formed. A study conducted in Nigeria showed that people were more satisfied when they were informed about their bad breath [20]. In this survey of 213 individuals, the primary reason for seeking such information was to identify potential solutions to the problem. In addition, perceptions of oral health vary by race and ethnicity. The 2018 Oral and Dental Health Profile Research Report, published in Turkey, revealed that 95.2% of the adult population owns their own toothbrush. Among this group, 25.1% of individuals brushed their teeth at least twice a day, whereas 38.0% brushed their teeth irregularly. These results suggest that oral hygiene habits remain suboptimal [21]. It can be postulated that halitosis resulting from poor oral hygiene may have become a less pressing concern for Turkish dentists. Although the students at Y University gave more positive responses, the majority of the students indicated that they did not discuss halitosis in their dental histories. Given its association with overall health and well-being, it is reasonable to conclude that patients are receptive to information and guidance regarding halitosis [22]. It is therefore imperative that dentists take greater responsibility for informing and educating their patients about halitosis and that dental students be encouraged to address this issue effectively. The differences in responses between universities indicate that there is no uniform approach to including questions related to halitosis in the dental history form, highlighting the need for standardization in this area.
In terms of experience, students from University X appeared to be more experienced than those from University Y. Although the relationship between number of patients treated and attentiveness was not assessed in this study, it could be a potential research question for future studies. Regarding halitosis, it may be posited that experience drives attentiveness. Although the relationship between number of patients treated and attentiveness was not assessed in this study, it could be a potential research question for future studies. Regarding halitosis, it may be posited that experience drives attentiveness.
The responses revealed that although fifth-year students were more likely to express a preference for referrals, students in general tended to treat patients with halitosis themselves and avoid referrals. When they do refer patients, they justify this decision by stating that they lack the necessary knowledge to treat halitosis. The most common referral option for halitosis is consultation within or outside the practice. In addition, the most cited reason for not referring was a lack of familiarity with the referral options available. Given that the majority of causes of halitosis are found in the oral cavity, it is clear that dentists must play a pivotal role in the evaluation and management of halitosis. A study conducted in India in 2019 revealed that university students outside the dental field lacked knowledge about extraoral factors associated with halitosis with the exception of gastrointestinal diseases [23]. This information asymmetry between patients and clinicians underscores the importance of the dentist’s ability to refer patients to appropriate resources.
The responses to the treatment protocol in the following section also support this assertion. The response rate to the questions in this section is relatively low. This finding indicates that there is little awareness of the existence of a specific halitosis treatment protocol. The majority of the students indicated that they did not have a treatment protocol for halitosis and that they considered existing treatment protocols to be ineffective. In a 2011 review, Loesch and Rösing reported that the majority of clinical procedures are based on opinion and that there is a paucity of scientific research on the topic [22]. To increase the effectiveness of educational programs, topics such as the biochemical mechanisms of halitosis, microbial aetiology, risk factors, and diagnostic criteria must be more fully integrated into the curriculum. In addition, preclinical simulation exercises focusing on halitosis assessment techniques, patient education, and treatment strategies should be incorporated to improve students’ clinical skills.
A review of students’ knowledge of halitosis indicates that fourth-year students are primarily gaining knowledge from current educational programs, whereas fifth-year students indicate a need for additional resources. These findings suggest that students who treat more patients with halitosis recognize the need for further information on diagnosis and treatment. A study conducted in Indonesia revealed that students enrolled in preclinical programs demonstrated superior knowledge compared with their counterparts in clinical programs [24]. While the discrepancy between preclinical and clinical students may not be directly attributable to clinical experience, both studies underscore a comparable concern: as clinical training intensifies, knowledge of and attention to halitosis may decrease. The fact that the fifth-year students in our study indicated a need for further education in this area serves to confirm the existence of this gap.
In the final section of the data form, an examination of the responses regarding knowledge of halitosis revealed that those of the Dutch students were comparable to those of the Turkish students in a previous study using this survey. However, in the aforementioned study, dental hygienists were found to have a greater proportion of correct responses. This may be because dental hygienists are more likely to interact with patients presenting with halitosis, thus gaining more experience in this area [15]. The results indicated that students who reported having a treatment protocol provided more accurate responses. This may indicate that an active treatment experience increases awareness and knowledge of bad breath. The majority of the students surveyed herein believed that bad taste in the mouth was associated with bad breath, a premise with a high rate of incorrect responses. However, the statement with the highest rate of correct responses was that bad breath disappears in the morning with breakfast and teeth brushing. These findings suggest that dental students are able to alleviate the symptoms of halitosis but lack an understanding of its aetiology and physiopathology. Furthermore, this conclusion can be drawn from personal experience without knowledge of the training program. In a 2019 study conducted in India, 62% of students reported an unpleasant taste in the mouth as a symptom of halitosis, a finding comparable to our own [25]. In a survey-based study conducted at Guilan University in 2018, fifth- and sixth-year students were found to be more knowledgeable than third- and fourth-year students [26]. The lack of significant differences in knowledge levels between students from different academic years may suggest that the curriculum does not address halitosis in sufficient depth. This suggests potential gaps in the depth and consistency of halitosis education among dental programs in Turkey. The fact that students at X University provided more correct answers may be related to the influence of multiple concurrent studies being conducted in the clinic. This finding underscores the potential positive impact that increased attention to the topic by academics and educators could have on student interest.
Our findings emphasized a crucial distinction between awareness and knowledge, both of which are essential for the effective clinical management of halitosis. Awareness, which is defined as students’ ability to recognize and address halitosis during patient interactions, appeared to improve with increased clinical exposure. In contrast, knowledge, which encompasses the understanding of the aetiology, diagnosis, and treatment of halitosis, has remained relatively consistent across academic years. Therefore, while students gain more awareness through experience, significant gaps persist in terms of their foundational knowledge. These outcomes underscore the need for dental curricula to foster both clinical awareness and theoretical understanding through ongoing education on halitosis.
Similar to many survey-based studies, this study has several limitations that should be acknowledged. First, self-report bias, social desirability bias, and acquaintance bias are potential limitations. Because the data rely on participants’ self-reported behaviours and knowledge, the surveys were administered anonymously, and the questions were carefully worded to minimize bias. However, despite these precautions, it cannot be guaranteed that some participants did not provide socially desirable answers or answers influenced by their acquaintances.
To address recall bias, we considered retrospectively reviewing internship records to objectively determine the number of patients with halitosis complaints. However, when we attempted this, we found that the records related to halitosis were significantly insufficient. Therefore, recall bias remains a limitation of our study.
We took several measures to minimize the risk of confirmation bias. Our study was conducted as a multicentre research project using a previously validated questionnaire to ensure reproducibility. In addition, our data analysis plan was clearly outlined and approved in our application to the ethics committee before the study began, and we strictly adhered to this plan. In particular, data analysis was performed by an independent statistician.
In addition, although the halitosis perception survey used in this study was valuable for assessing students’ general knowledge and treatment approaches, it had certain limitations. Unlike more detailed surveys, such as that of Grzech-Leśniak et al., our survey did not explore in depth the practical aspects of halitosis management, including classification, aetiology, and specific diagnostic tools [27]. In addition, the students’ limited clinical experience meant that their practical knowledge of halitosis treatment and management was not fully assessed, which may have hindered a full understanding of their knowledge of new treatment strategies and diagnostic procedures.
It would be beneficial for universities to include a section on halitosis in the medical and dental history forms they use. It is of paramount importance to instil confidence in students to address and question halitosis. The functionality of existing treatment protocols in dental schools should be reviewed, and a common protocol for halitosis should be established, given the multidisciplinary nature of this condition. The creation of a specific module on halitosis as a compulsory part of the curriculum and the introduction of interdisciplinary case discussions to support it would significantly improve the quality of education. The introduction of structured clinical examinations to objectively assess student performance would further enhance the effectiveness of the educational process. These initiatives could broaden the scope of dental education and better equip future dentists in halitosis management.
Conclusions
The findings suggest that as students interact with an increasing number of patients presenting with halitosis, their awareness and recognition of the need for further information and referral opportunities also increase. As these students will ultimately become the region’s future dentists, it is likely that this need will persist throughout their professional careers. A general lack of knowledge and attention to halitosis is evident.
Acknowledgements
We would like to express our gratitude to Yvonne Buunk-Werkhoven, Ph.D., for kindly sharing her survey with us, which greatly facilitated our research. Additionally, we would like to thank Assoc. Prof. Dr. Büşra Yılmaz for her assistance during the revision process. Her support was helpful in improving the quality of our study. Finally, we extend our thanks to the students of both universities for their participation and contributions to this research. Their cooperation made this study possible.
Author contributions
Emine Nur Kahraman: Conceived and designed the study, and drafted the initial manuscript.Şehrazat Evirgen: Collected and analyzed data, and conducted the literature review.Ahu Dikilitaş: Interperated the questionnaire, organized the translation, revised the manuscript.Ayşe Gülşahı: Collected data from the other university, and contributed to data interpretation.Esra Özge Aydın: Conducted the literature review and get the ethical approval.Funda Özalp: Performed statistical analysis, interperated the data.All authors reviewed the manuscript.
Funding
Not applicable.
Data availability
The datasets generated and/or analysed in the current study are available from the corresponding author upon reasonable request.
Declarations
Ethics approval and consent to participate
This study was conducted in accordance with the ethical standards outlined in the Declaration of Helsinki and was approved by the Ethics Committee of Uşak University. Approval was given on 10.03.2021 during the meeting of the committee, with reference number 55-55-09. All participants provided informed consent prior to their participation in the study.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets generated and/or analysed in the current study are available from the corresponding author upon reasonable request.