The trends of oral self-care and tobacco use among Iranian senior dental students during a decade were assessed to understand their conditions as future health-promoters. About one third of male students reported RTH and the rate of reported smoking among female students remained constant (15%) throughout the study period leaving plenty of room for improvement.
Dental professionals should first serve as role models for the public . Role modeling can be seen as important educational method. Within health care education role modelling is used not only to convey knowledge as a means of effective learning, but also it is a means to embed the students with such qualities as behaviour, attitudes and values .
A sampling method with stratification to collect representative data from all Iranian dental schools was applied. Additionally, the high response rate in all occasions with an overall response rate of 81% speaks for the representativeness of our sample. Using a self-administered questionnaire as a data collection tool may cause social desirability bias resulting in underestimation rather than overestimation of the behaviours reported.
In agreement with previous studies on Iranian dentists, female senior dental students reported more favorable RTH than their male counterparts . In the present study, the difference in RTH between male and female students unfortunaterly decreased from 2008 to 2015 as a result of decreased adherence of female students to RTH. The current study showed that adherence to RTH was more prevalent in non-smokers, which is in concordance with other studies in China, United States and Greece. [13–15]. Ghasemi et al. (2015) also reported that adherence to recommended oral self-care in smoking dental professionals was less than their non-smoker counterparts in Iran .
The overall ten-year trend of smoking prevalence among students surveyed showed no significant variation. In contrast to the present results an increasing trend in the prevalence of smoking among Iranian adolescents from 2002 to 2013 has been reported. In the present study the prevalence of smoking in dental students was 22.5%-28.5%, which is higher than that in Australia (13%) , Ireland (20%)  and Jordan (17%) , but lower than that in Romania (37.3%)  and Belgium (25%) .
As also reported in a previous study (22), the smoking rate among senior dental students was reported higher than that among the Iranian general population. In national surveys, the prevalence of smoking is reported to be 17.4% in Iranian students (23), 8.5% in 16 to 25-year-old young people , and 18.3% in males and 1.3% in females in the age group of 19–49 years . Smoking rates reported were significantly more prevalent in males than females, which is similar to the findings of previous studies in Iranian senior dental students [22, 26], oral health professionals , and Iranian general population . This can be a result of less social acceptance of women’s smoking in Iran, or their better health consciousness.
Data of previous studies in Iran shows that only 5% of tobacco use among Iranian youth population is smokeless [22, 27]. The most common types are cigarette, water pipe and cigar. Therefore, the questions applied only to various types of tobacco smoking in the present study. In line with previous findings , Smoking water pipe was the most popular tobacco use, and its prevalence was high in comparison with cigarette and pipe, even among women. This can be due to a traditional belief that hookah is less harmful although there is scientific evidence that even smoking hookah (shisha) plays a significant role in the development of lung cancer, respiratory diseases, low birth weight, and periodontal problems . Moreover, less social stigma is attached to hookah than other types of tobacco smoking.
During the 10-year study period the Tobacco Prevention and Control Research Center of Iran has organized national anti-smoking programs to decrease tobacco use among population. These projects are based on nationۥs need, partnership and collaboration with NGOs in health field providing educational, treatment and counseling services of smoking cessation. The projects also include training workshops on methods of smoking cessation for health care workers. However, the smoking population has increased in the country  showing challenges of such health promotion programs. An important social change with a possible effect on successfulness of such programs, and also on the present findings, is the rapid and pervasive diffusion of social networks, especially among youths, during these ten years. These networks are used mainly as entertainment. Moreover, youths spend a lot of time in these networks, which may have some adverse effects on their lifestyle, including health behaviours.
The role of sosio-economic background of dental students in their health behaviour seems somewhat controversial as compared to earlier studies. In our study, in the regression models, RTH showed no significant association with parents’ education level. Khami et al (2010) concluded that the prevalence of smoking increased in dental students with an increase in the father’s educational level . This is in contrast with the results of an earlier study that showed a lower educational level of the father increased the odds of smoking in Iranian young people . Our sample was selected from state universities of country, which accept students with varying socio-economic status (SES). It is reasonable to expect that professional training of students with any SES could eliminate the effect of some background factors putting students on the same line as health promotors.
There are several studies emphazising significance of teaching prevention in educational programs of health professionals to facilitate paradigma change and appreciation of prevention (30). The national curriculum of undergraduate dentists has been revised during the study period to emphasize prevention including smoking cessation activities (31). However, based on the findings of the present study, results of such educational activities still remains to be seen and further research is needed. Also, significance and potential of role modeling in dental education should be appreciated to avoid unprofessional behaviour among future dentists. This should particularly be targeted to those students with extra need of guidance . These activities could help dental students as future dentists to develop professional characteristics that would facilitate them to serve as role models for the public in acquiring and maintaining health-promoting behaviours.