Impact of Smoking on Oral Health: Knowledge and Attitudes of Croatian Dentists and Dental Students.

OBJECTIVE: The aim of this study was to evaluate smoking habits, the level of knowledge and attitudes towards smoking, as well as the role of dental professionals in prevention of smoking among students of the School of Dental Medicine, University of Zagreb and compare them to attitudes of practicing Croatian dentists.
MATERIALS AND METHODS: The study was carried out among 1st and 6th year dental students at the School of Dental Medicine, University of Zagreb and dentists employed in primary practice throughout Croatia. A total of 159 subjects (51 1st and 53 6th year dental students and 55 dentists) participated in the study.
RESULTS: The prevalence of smoking was highest among 6th year dental students (39, 6%). It slightly decreased among dentists (34, 5%), while least smokers were found among first year dental students (7, 8%). The majority of dental student smokers expressed a desire to stop smoking (66, 7% of 1st year dental student smokers and 76% of 6th year dental student smokers), while less than half of dentist smokers had the desire to stop - only 45, 8% of them. Dental students of the 1st and 6th year of the study showed a statistically significantly higher level of desire for education about harmful smoking effects and patients counselling to quit smoking compared to dentists. The data gathered in this study indicate that it is necessary to increase awareness among dental professionals about harmful effects of smoking on oral and general health. Also, their awareness about the central role of healthcare workers as promoters of a healthy lifestyle among patients should be raised.

Introduction

Tobacco smoking, along with hypertension and obesity, is considered the leading preventable cause of death in the world (). As a result of smoking, more than 9,000 people - roughly one in five deaths die in Croatia every year. According to the latest data, 33% of the Croatian population are smokers, of which 37% are men and 30% women. One in two smokers in Croatia tried to quit smoking at least once, but only 16% of them succeeded ().

The adverse effects of tobacco smoking on oral health are well documented. This includes common and rare conditions, from benign to life-threatening diseases such as discoloration of teeth and dental restorations, bad breath, taste and smell disorders, impaired wound healing, periodontal disease, short-term and long-term implant success, oral mucosal lesions such as smoker's melanosis and smoker's palate, potentially malignant lesions and oral cancer ().

Health professionals, including dentists and their teams, have ethical, moral and professional obligations to help patients quit smoking. Due to the nature of their work and regular contact with patients, the dentist is in an ideal position to advise their patients about smoking cessation. Dentists have the necessary skills, competence and expertise for the recognition and treatment of oral lesions associated with smoking and can advise patients about harmful effects of smoking, as well as benefits of smoking cessation (). Dentists' activity in the prevention of smoking will have a double effect for patients: not only quitting smoking will improve oral health, but will also contribute to prevention of systemic diseases associated with smoking (). The Guideline on smoking cessation counselling include "5P Protocol" - a short briefing which in five steps examines the patient's smoking habits and his willingness to quit. A large number of smokers fail three to five times in the course of withdrawal before they finally manage to quit smoking (), and the role of the entire dental team is to provide support and encouragement during this period.

The aim of this study was to evaluate smoking habits, the level of knowledge and attitudes towards smoking, as well as the role of dental professionals in the prevention of smoking among students of the School of Dental Medicine, University of Zagreb and compare them to the attitudes of practicing Croatian dentists.

Materials and methods

This study included a total of 159 subjects: 51 1st year dental students and 53 6th year dental students, which amounts to nearly 50% of the students of the first and sixth year, and 55 practicing dentists. The study was conducted among 1st and 6th year dental students at the School of Dental Medicine, University of Zagreb and the dentists employed in primary practice throughout Croatia using an attached questionnaire. The questionnaire was completely anonymous. No personal information such as names, surnames, dates of birth, addresses etc. were registered. The questionnaire consisted of four parts: the first part of the questionnaire examined general parameters of subjects such as sex, age group, and belonging to one of three test groups.

The second part of the questionnaire examined the current and previous experience of smoking, age of first experience of tobacco smoking, the number of cigarettes smoked each month, and willingness to stop smoking. Also, it examined daily exposure to tobacco smoke, and the possible existence of smoking ban at college campus or workplace.

In the third part of the questionnaire, which is based on the available literature (, , -), 15 statements were made on the impact of smoking on oral cavity with three possible answers: YES, NO and DO NOT KNOW.

The fourth part of the questionnaire contained 15 statements that assessed the respondent's personal attitude towards tobacco smoking and the dentist’s role in the prevention of smoking and smoking cessation counselling for patients. The attitudes of respondents were assessed using a 5 stage Likert scale which indicated the level of agreement with a particular statement (from 1 - strongly disagree, to 5 - completely agree).

The data were organized in spreadsheet files (Microsoft Excel, Microsoft Inc. USA) and statistically analyzed using the SPSS (IBM Inc, USA). The normality of data distribution was tested by the Kolmogoroff- Smirnov test and it was found that data were normally distributed. Measures of central tendency were used (minimum, maximum, mean, standard deviation) for data presentation. To test differences between groups, the chi - square test for nominal and Student's t - test for ordinal variables were used. P - Values lower than 0.05 (p < 0.05) were considered statistically significant.

Results

According to demographic data collected in the first part of the questionnaire (Table 1), a significantly higher proportion of women comparing to men was found among first and sixth year students, compared to dentists.

Table 1

Demographic data

Spol N(%) / Sex N(%)	Studenti 1. godine / 1st year students	Studenti 6. godine / 6th year students	Stomatolozi / Dentists
Ženski / Female	44 (86.3)	44 (83)	34 (61.8)
Muški / Male	7 (13.7)	9 (17)	21 (38.2)
Dobna skupina N(%) / Age group N(%)
18-30	50 (98)	53(100)	9 (16.4)
31-40	1 (2)		20 (36.4)
41-50			13 (23.6)
51 i više / 51 and more			13 (23.6)
Zaposlenje* N(%) / Employment* N(%)
Dom zdravlja / Community health centre			17 (30.9)
Privatna ordinacija / Private practice			14 (25.5)
Ugovorna ordinacija / Practice under the contract with HZZO			24 (43.6)

*samo za stomatologe / *dentists only

The second part of the questionnaire examined previous experience of tobacco smoking and the current smoking habits (Table 2). The prevalence of smoking was highest among 6th year dental students (39, 6%). It slightly decreased among dentists (34, 5%), thus pointing to the fact that these results are consistent with the national average (33% of Croatian population are smokers) (), while least smokers were found among first year dental students (7,8%). Although a significantly larger number of non-smokers were found among 1st year dental students compared to 6th year dental students and dentists, a larger number of 1st year dental students started smoking at an earlier age compared to 6th year dental students and dentists.

Table 2

Experience of tobacco smoking and exposure to tobacco smoke

	Studenti 1. godine / 1st year students	Studenti 6. godine / 6th year students	Stomatolozi / Dentists	p
Pušite li? N(%) / Do you smoke? N(%)
Da / Yes	4 (7.8)	21 (39.6)	19 (34.5)	0.003*
Ne / No	36 (70.6)	27 (50.9)	30 (54.5)
Povremeno / Occasionally	11 (21.6)	5 (9.5)	6 (10.9)
Jeste li ikada u prošlosti probali cigarete / pušili? N(%) / Have you ever smoked? N(%)
Da / Yes	40 (78.4)	44 (83)	45 (81.8)	0.826
Ne / No	11 (21.6)	9 (17)	10 (18.2)
S koliko godina ste prvi put probali cigarete? N(%) / Age of first experience of tobacco smoking? N(%)
Manje od 12 / Less than 12	2 (3.9)	0	2 (3.7)	0.001*
12-18	37 (72.5)	27 (50.9)	22 (40.7)
19-25	1 (2)	17 (32.1)	17 (31.5)
Nakon 25 / After 25	0	0	2 (3.7)
Nikad nisam pušio / la / I have never smoked	11 (21.6)	9 (17)	11 (20.4)
U posljednjih mjesec dana, koliko dana ste pušili? N(%) / In the past month, how many days have you smoked?
0	37 (72.5)	27 (50.9)	31 (56.4)	0.003*
0-5	9 (17.6)	3 (5.7)	3 (5.5)
5-10	2 (3.9)	4 (7.5)	4 (7.3)
10-25	1 (2)	7 (13.2)	2 (3.6)
više od 25 dana / more than 25 days	2 (3.9)	12 (22.6)	15 (27.3)
Imate li želju prestati pušiti? + (N%) / Do you have a desire to quit smoking? + (N%)
Da / Yes	10 (66.7)	19 (76)	11 (45.8)	0.086
Ne / No	5 (33.3)	6 (24)	13 (54.2)
U posljednjih tjedan dana, koliko puta ste bili izloženi duhanskom dimu u svom domu? / In the past week, how many times have you been exposed to tobacco smoke in your home?
0	31 (60.8)	31 (58.5)	37 (66.7)	0.001*
1-2 dana / 1-2 days	10 (19.6)	4 (7.5)	2 (3.7)
2-6 dana / 2-6 days	6 (11.8)	8 (15.1)	0
svih 7 dana / all 7 days	4 (7.8)	10 (18.9)	16 (29.6)
U posljednjih tjedan dana, koliko puta ste bili izloženi duhanskom dimu u javnim prostorima? / In the past week, how many times have you been exposed to tobacco smoke in public places?
0	6 (11.8)	4 (7.5)	10 (18.2)	0.670
1-2 dana / 1-2 days	24 (47.1)	24 (45.3)	21 (38.2)
2-6 dana / 2-6 days	16 (31.4)	16 (30.2)	17 (30.9)
svih 7 dana / all 7 days	5 (9.8)	9 (17)	7 (12.7)
Postoji li na Vašem fakultetu / radnom mjestu službena zabrana pušenja? / Is there official smoking ban in your college / workplace?
Da / Yes	33 (64.7)	51 (96.2)	49 (89.1)	p<0.001
Ne / No	1 (2)	0	6 (10.9)
Nisam siguran / a / I'm not sure	17 (33.3)	2 (3.8)	0

+ samo za pušače / + smokers only

* statistički značajna razlika (p < 0.05) / * statistically significant result (p < 0.05)

Unlike students, among which the majority of smokers stated that they wanted to quit smoking (66.7% of 1st year dental student smokers and 76% 6th year dental student smokers), less than half of dentists-smokers had the desire to stop - only 45,8% of them.

The third part of the questionnaire was related to the level of existing knowledge about impact of smoking on the oral cavity, and results showed statistically significant differences in subjects' knowledge (Table 3). First year dental students had statistically significant less correct answers to almost all questions compared to 6th year dental students and dentists.

Table 3

Knowledge about the impact of tobacco smoking on oral health

	Tvrdnja / Statement	Ne (%) / No (%)	Da (%) / Yes (%)	Ne znam (%) / I don't know (%)	p
1.	Pušenje je povezano s nastankom raka usne šupljine. / Smoking is associated with development of oral cavity cancer.	0	155 (97.5)	4 (2.5)	0.013*
2.	Prestankom pušenja smanjuje se rizik za razvoj oralnog karcinoma. / Quitting smoking reduces the risk of developing oral cancer.	4 (2.5)	147 (92.5)	8 (5)	0.006*
3.	Pušenje ugrožava zdravlje pasivnih pušača u okolini pušača. / Smoking endangers passive smokers health.	0	158 (99.4)	1 (0.6)	0.345
4.	Brzim pregledom oralne sluznice pacijenta moguće je otkriti rak usne šupljine / prekancerozne lezije u najranijem stadiju. / It is possible to detect cancerous / pre-cancerous lesions at the earliest stage by quick inspection of patient’s oral mucosa.	16 (10.1)	105 (66)	38 (23.9)	<0.0001*
5.	Svaku suspektnu oralnu prekanceroznu leziju nužno je poslati na biopsiju. / Any suspicious oral precancerous lesion should be sent to biopsy.	4 (2.5)	131 (82.4)	24 (15.1)	<0.0001*
6.	Rak usne šupljine najčešće se otkrije u uznapredovalom stadiju. / Oral cancer is most commonly discovered in advanced stage.	18 (11.3)	99 (62.3)	42 (26.4)	<0.0001*
7.	Pušenje izaziva psihičku, ali ne i fizičku ovisnost. / Smoking causes psychic but not physical dependence.	81 (50.9)	57 (35.8)	21 (13.2)	0.244
8.	Alkohol u kombinaciji s pušenjem povećava mogućnost razvoja raka usne šupljine. / Alcohol combined with smoking increases possibility of developing oral cancer.	5 (3.1)	123 (77.4)	31 (19.5)	<0.0001*
9.	Rak usne šupljine u ranim fazama je asimptomatski. / Oral cancer is asymptomatic in early stages.	7 (4.4)	107 (67.3)	45 (28.3)	<0.0001*
10.	Prekancerozne lezije u manjem broju slučajeva maligno alteriraju. / Pre-cancerous lesions in a small number of cases malignantly alter.	19 (11.9)	84 (52.8)	56 (35.2)	<0.0001*
11.	Pušenje predstavlja rizični faktor za razvoj akutnog ulceroznog nekrotizirajućeg gingivitisa. / Smoking is a risk factor for development of acute ulcerative necrotizing gingivitis.	11 (6.9)	111 (69.8)	37 (23.3)	<0.0001*
12.	Pušačka melanoza spada u prekancerozna stanja. / Smokers melanosis is a precancerous condition.	45 (28.3)	42 (26.4)	72 (45.3)	<0.0001*
13.	Za postavljanje dijagnoze crnog dlakavog jezika nužna je biopsija. / Biopsy is required for black hairy tongue diagnosis.	114 (71.7)	6 (3.8)	39 (24.5)	<0.0001*
14.	Pušenje predstavlja čimbenik rizika za zubni karijes. / Smoking is a risk factor for dental caries.	70 (44)	62 (39)	27 (17)	<0.0001*
15.	Pacijentima s leukoplakijom uputno je raditi biopsiju jednom godišnje. / Leukoplakia patients are advised to have biopsy once a year.	17 (10.7)	80 (50.3)	62 (39)	<0.0001*

The fourth part of the questionnaire examined attitudes about tobacco smoking and the dentists' role in the prevention of smoking (Table 4). Dentists had statistically significantly higher disagreement with the statement that the dentist’s duty is to educate the patient about the dangers of tobacco smoke and suggest smoking cessation. In addition, dentists more often than students believed that there was a small possibility that their suggestion to stop smoking would affect the patient, and they expressed a greater degree of agreement with the statement that smoking is a matter of personal choice and private risk and that they have no right to interfere.

Table 4

Attitudes about tobacco smoking and the dentists' role in the prevention of smoking

Tvrdnja / Statement	Stupanj slaganja s tvrdnjom+% / Stage of agreement with statement+ %					p
	1	2	3	4	5
Smatram da je pušenje cigareta izuzetno štetno za zdravlje. / I find smoking cigarettes extremely harmful to health.		1.9	3.1	20.8	74.2	0.341
Dužnost stomatologa je da pacijenta educira o štetnosti duhanskog dima te mu sugerira prestanak pušenja. / The dentist's duty is to educate the patient about the dangers of tobacco smoke and suggest smoking cessation.	2.5	3.8	9.4	15.7	68.6	0.044*
Stomatolog svojim nepušenjem treba predstavljati uzor pacijentima. / Dentist should serve as a role-model for patients by his non-smoking behaviour.	10.1	4.4	11.9	10.7	62.9	0.276
Velika je šansa da će stomatologova sugestija o prestanku pušenja utjecati na pacijentovu odluku o prestanku pušenja. / There is a great chance that the dentist's suggestion of smoking cessation will affect the patient's decision to stop smoking.	21.5	24.1	34.2	12	8	0.031*
Pušenje je stvar osobnog izbora pojedinca i stomatolog se nema pravo uplitati. / Smoking is a matter of personal choice and the dentist has no right to interfere.	24.1	22.2	29.7	13.3	10.8	0.001*
Dužnost stomatologa je trudnici koja puši sugerirati prestanak pušenja te objasniti moguće štetne posljedice nastavka pušenja za plod. / The dentist's duty is to suggest smoking cessation to pregnant woman who smokes and to explain possible damaging consequences of smoking for fetus.	3.8	1.9	3.8	12	78.5	0.051
Dužnost stomatologa je roditelje pušače informirati o rizicima pasivnog pušenja za njihovu djecu te ostale ukućane. / Dentist's duty is to inform the parents about the risks of passive smoking for their children and other households members.	1.9	5.1	19.6	16.5	57	0.163
Stomatolog treba biti dostatno educiran o utjecaju pušenja na zdravlje. / The dentist should be adequately educated about the impact of smoking on health.	1.9	2.6	4.5	14.7	76.3	0.013*
Moje trenutno znanje je dovoljno za savjetovanje pacijenata o prestanku pušenja. / My current knowledge is sufficient for patients counseling on smoking cessation.	11.4	11.4	23.4	24.1	29.7	<0.0001*
Studentima / stomatolozima je potrebna bolja edukacija o savjetovanju pacijenata za prestanak pušenja. / Students / dentists need better education on patients counseling about smoking cessation.	3.8	7	28.7	34.4	26.1	0.225
Kad bi bilo specifičnog kolegija / tečaja o štetnim učincima pušenja te savjetovanju pacijenata za prestanak pušenja, pohađao / la bih ga. / If there had been a specific course about harmful effects of smoking and the patients counseling for smoking cessation, I would have attended it.	10.8	6.3	25.9	25.9	31	0.010*
Zabrana pušenja u svim prostorima zdravstvenih ustanova ima veliku ulogu u promociji zdravog okruženja bez duhanskog dima. / Smoking ban in all areas of health care institutions has a major role in promoting a healthy environment without tobacco smoke.	2.5	6.3	8.2	12.7	70.3	0.510
Zabrana pušenja u javnim prostorima pridonijela bi osvještavanju javnosti o štetnosti duhanskog dima. / Smoking ban in public spaces would have contributed to public awareness of dangers of tobacco smoke.	3.2	7	20.4	19.7	49.7	0.169
Zabrana pušenja u javnim prostorima predstavlja kršenje prava pušača. / Smoking ban in public space is violation of smokers rights.	56.3	9.5	17.7	7	9.5	0.054
Davanjem savjeta o pušenju mogla / mogao bih izgubiti pacijenta. / By giving advice on smoking I could lose my patient.	27.4	16.6	35	16.6	4.5	0.018*

+ 1 - U potpunosti se ne slažem; 2 - Ne slažem se; 3 - Niti se slažem niti se ne slažem; 4 - Slažem se; 5 - U potpunosti se slažem / + 1 - I completely disagree; 2 - I disagree; 3 - I do not agree or disagree; 4 - I agree; 5 - I completely agree

* statistički značajna razlika (p < 0.05) / * statistically significant result (p < 0.05)

Dental students of the 1st and 6th year compared to dentists showed a statistically significantly higher level of desire for education about harmful smoking effects and patients counselling to quit smoking compared to dentists. Also, a larger number of students believed that dentist should be sufficiently educated about harmful effects of smoking on health compared to dentists.

Discussion

This study gives us insights into habits, knowledge and attitudes of respondents towards the problem of smoking and the dentist’s role in the prevention of smoking.

Higher percentages of smokers were found among 6th year dental students and dentists, compared to 1st year dental students. On the other hand, 1st year dental students began smoking at an earlier age than 6th year dental students and dentists. This indicates that young people nowadays experiment with tobacco smoking at an earlier age, and that there is a need for anti-smoking campaigns, in particular the need for organized forms of education in primary and secondary schools, in order to prevent even earlier experimentation with cigarette smoking among young people.

A higher proportion of dental student smokers expressed a desire to stop smoking compared to less than half of dentist smokers. Such results could be explained by already established addiction, as well as long-standing habits that are very difficult to stop, as evidenced by the fact that very few smokers manage to quit after the first attempt ().

First year dental students showed a lower level of knowledge on smoking cessation compared to the 6th year dental students and dentists, which is expected given that they are at the beginning of their dental education and still lack specific theoretical and practical knowledge. It is worrisome that almost a third of respondents did not know that oral cancer could be detected at the earliest stage just by examination of the oral mucosa, and that, in practice, oral cancer is usually discovered in an advanced stage. Because of the availability of oral tissues to the dentist’s eye, it is important to educate the current and future dentists about the importance of inspection of oral mucosa during a routine dental check-up (, ).

The data obtained in the fourth part of the study, in which attitudes about tobacco smoking and the dentists' role in smoking cessation were examined, yielded some interesting results. Dentists have shown less interest in the activities of patients counselling for the purpose of informing, preventing and stopping smoking than dental students. Also, dentists thought more often that their patients’ smoking habits are private matters and that they have no right to interfere. This may be explained by the lack of awareness about the dentist’s role in the prevention and control of smoking in the population, as well as lack of knowledge about harmful effects of tobacco smoke and its long-term consequences, and poor practical measures that would educate healthcare workers about the techniques of patients counselling for smoking cessation, as well as lack of financial support by the insurer, all confirmed by some studies in the literature review (). In addition, more than half of dentist smokers had no desire to quit smoking and it is expected that their motivation for patients counselling would not be high. Subjects' opinions on the dentist’s role in the activities against smoking vary from study to study. According to the study of Dable et al. (), dental students have also shown a positive attitude towards dentists' roles in counselling for smoking prevention and cessation, and the authors have also proved that the implementation of educational programs and student retirement programs during the study can play a significant role in their motivation for future anti-smoking activities. Similar results were reported by Yip et al. () and Alrsheedi et al. (). On the other hand, the study results obtained by Uti et al. () showed that Nigerian dentists and dental students are negatively inclined to the role of dentists as health workers in the global anti-smoking campaign and activities that would encourage dentists to conduct smoking cessation activities. In addition, dentists and dental students do not generally believe that their advice may affect the patient's decision about quitting. Uti et al. () believe that this negative attitude may be due to lack of education and lack of formal training on smoking cessation. Moreover, in countries where poor organization of the health system and the lack of workforce are burdened with a large number of emergency patients, even three minutes for smoking counselling may pose a luxury that these dentists cannot afford ().

All of the above suggests that dentists lack enthusiasm for smoking cessation activities compared to dental students, which is why education about given subject should be available within academic programs. Besides, it should become part of lifelong learning. It is necessary to increase the awareness of dental professionals about negative effects of smoking on oral and general health. Furthermore, they should be more aware of their central role of healthcare workers as promoters of healthy lifestyle among patients. Also, it is necessary to develop specific courses in which participants could learn basic techniques for smoking cessation counselling, thus providing education materials and offering support for healthy decision-making among patients. These methods are not time consuming and do not require significant financial resources. Along with other anti-smoking activities, these measures could contribute to major changes in public views of cigarette smoking and smoking habits of society.