Attitudes of Students of Differenet Schools of University of Zagreb on Tooth Bleaching

Abstract

Objective

To compare the awareness that students from four different faculties within the University of Zagreb have of oral health and tooth bleaching procedure.

Materials and Methods

The study included 158 subjects (both male and female) - 38 students from the School of Dental Medicine and 40 students from each of the following faculties: the School of Medicine, the Faculty of Economics and the Faculty of Civil Engineering. The respondents were asked to fill out the survey with multiple choices by marking the answers they considered correct.

Results

Only 12% of the respondents followed the information on oral health. More than two thirds of all subjects brush their teeth twice a day, but there were no statistically significant differences between the subjects with respect to college or gender. More than half of the participants (55%) were satisfied, and 12% were completely satisfied with their dental appearance. About 80% of the respondents were aware of differences between teeth bleaching and teeth polishing procedures, with greater prevalence among Dental Medicine and Medicine students. 80% of all subjects would go to a dental office if they decided to whiten their teeth while less than a half (46%) of all the subjects believed that a tooth bleaching has some adverse side-effects.

Conclusions

There is a difference in knowledge on oral hygiene and tooth bleaching between the students from the School of Dental Medicine, the School of Medicine, the Faculty of Economics and those from the Faculty of Civil Engineering. Dental students have the best knowledge on tooth bleaching and oral health, which was in accordance with their educational guidance and level of education.

INTRODUCTION

The desire for a beautiful smile has been present throughout ages. Since a smile and the teeth are the most dominant details of our faces, it is not surprising that a beautiful smile and white teeth have become such a strong imperative, which is particularly evident at the present time. Tooth color is variable and numerous, and it is the result of the tooth structure and a combination of organic and inorganic components of the enamel and dentin and spectral distribution of incoming light (1-3). Certain factors trigger a cascade of chemical reactions in the tooth structure and thereby cause its discoloration. Considering the causes, discoloration can be endogenous (4-7) and exogenous (8, 9).

Tooth bleaching is considered the easiest and most cost-effective procedure for treating tooth discoloration. Bleaching can be performed internally on non-vital teeth or externally on vital teeth. Bleaching can be performed by applying carbamide peroxide, hydrogen peroxide or sodium perborate with/without additional light activation. There are different types of vital teeth bleaching procedures including in-office bleaching using high concentrations of bleaching agents with adequate soft tissue protection or at home bleaching procedures with lower concentration of bleaching agents (10-12). The mechanism of bleaching is also unclear. Bleaching is considered to be an oxidation reaction where hydrogen peroxide metabolizes into water and free radicals possess a single electron, which is thought to combine with the chromagens to decolorize or soubise them (13, 14).

Since tooth bleaching has become a common dental procedure, there are concerns about the biologic adverse effects of hydrogen peroxide. The collected data show that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. Cervical root resorption is a possible consequence of internal bleaching. Bleaching products do not cause major alterations of enamel and dentin structures or their surfaces. For a successful therapy, it is essential to define indications and contraindications, to correctly set the diagnosis and to select the most suitable tooth-whitening technique (15-17).

The aim of this study was to compare the awareness which students from four different faculties belonging to the University of Zagreb have about oral health and tooth bleaching procedures. The null hypothesis was that there is no difference in knowledge on oral hygiene and tooth bleaching between the students from the School of Dental Medicine, the School of Medicine, the Faculty of Economics and the Faculty of Civil Engineering.

SUBJECTS AND METHODS

The study was approved by the School of Dental Medicine, University of Zagreb Ethics Committee. The study included 158 participants (both male and female) - 38 students from the School of Dental Medicine and 40 students from each faculty as follows: the School of Medicine, the Faculty of Economics and the Faculty of Civil Engineering. The purpose of this study was explained to all participants and they were kindly requested to sign the consent.

After that, the respondents were asked to fill out the survey with multiple choices by marking the answers they considered correct (Figure 1). A statistical analysis was performed using SPSS System. Since the data distribution was not normal, the nonparametric Pearson chi-squared and Anova T- test were used.

Figure 1.

Survey on oral hygiene and tooth bleaching

RESULTS

Out of the participants surveyed at the School of Dental Medicine, 71.05% were female students, and the rest of them were male students. Similar percentages were found among the students from the School of Medicine and Faculty of Economics, while both sexes were equally represented at the Faculty of Civil Engineering. Age distribution is shown in Table 1. The participants of the study believed that physical appearance is important, but not crucial. The results of the abovementioned study revealed that the respondents’ answers did not differ much regarding gender, age or college. Information on oral health is only followed by 12% of subjects, mostly students from the School of Dental Medicine (29%). More than two thirds of all subjects brush their teeth twice a day, which shows that they are aware of the importance of oral health, but there was no statistically significant difference between the subjects with respect to college or gender (Figure 2). Although oral hygiene and interest about the oral hygiene is different between the subjects, it is interesting that the satisfaction with their own teeth is quite similar among the respondents. More than half of the subjects (55%) were satisfied, and 12% of them were completely satisfied by the appearance of their teeth, however, mostly female students (Figure 3). About 80% of the subjects make difference between the procedures of teeth bleaching and teeth polishing. A greater prevalence was observed in dental and medical students (Figure 4). Regarding media, television is the main medium through which they learn about the teeth bleaching procedures. One third of all the subjects who participated in the study (34%) would like to whiten their teeth. Male students are less interested in bleaching procedures (25%) compared to female students (39%). The students from the School of Dental Medicine have higher awareness about oral hygiene and, also, a better knowledge on oral health and tooth bleaching compared to other students. 80% of all subjects would go to dental office if they decided to whiten their teeth (Figure 5). Less than a half (46%) of all the subjects considered that tooth bleaching has some adverse effects.

Table 1. Description of samples.

		SEX		Total
		Male	Female
	18-20	14	16	30
	21-23	31	84	115
	24-26	10	1	11
	26 +	1	1	2
Total		56	102	158

Figure 2.

Tooth brushing frequency

Figure 3.

Satisfaction with own teeth

Figure 4.

Difference between teeth bleaching and teeth polishing.

Figure 5.

Option between at home or in-offic bleaching treatment

DISCUSSION

Our study included 38 students from the School of Dental Medicine and 40 students from other faculties within the University of Zagreb: the School of Medicine, the Faculty of Economics and the Faculty of Civil Engineering. According to previous studies, dental students have better oral hygiene (18) and better knowledge on tooth bleaching, which can be explained by education they receive during the study of dental medicine and by their attitude towards oral health (18, 20, 21). Šimat et al. (18) reported that students from the School of Dental Medicine have better oral hygiene habits than students from other faculties, while DMFT index is associated with a lack of prevention at a young age, regardless of the group of subjects. Similar results were obtained by Peker at al. who reported that the overall knowledge of oral health has improved in dental students with increased education (19). According to our results, female students visit their dentist at least once each year for a regular dental checkup, brush their teeth twice a day or more, and use dental floss. Also, a higher percentage of female dental students (80%) would like to whiten their teeth compared to male students. These results are expected since women pay more attention to oral hygiene, health and their appearance, which is similar to the results obtained by Peker et al. (19).

About two thirds of the subjects visit their dentist for a preventive dental checkup once in six months or more often, and the difference was found between sexes (females 70%, males 61%) in comparison to their college orientation where no statistically significant differences were found. 82% of dental students visit their dentist for a control dental check-up every 6 months, while only 55% of medical students visit their dentist for a control dental check-up, which was not expected (18, 22). Chrysanthakopoulos found that medical students in Greece did not possess good knowledge on oral health during their preclinical and clinical studies, but it increased as they progressed in their clinical part of education (22). When the respondents were asked whether there were any differences between tooth bleaching and tooth polishing it turned out that there was a statistically significant difference, which was in accordance with the type of their education i.e. vocational orientation (χ²=34,293, df=6, expected χ²=12,592). 78% of the subjects thought there was a difference between those two dental procedures; however the percentage was higher among dental and medical students (Table 2 and Figure 4). According to the results obtained in previous studies, the null hypothesis claiming that there was no difference in knowledge about oral hygiene and tooth bleaching among different students was rejected.

Table 2. Difference between tooth bleaching and tooth polishing.

			FACULTY								Total
			Dental Medicine		Medicine		Economics		Civil Engineering
	yes	freq.	36		37		29		22		124
		%	94.7%		92.5%		72.5%		55.0%		78.5%
	no	freq.	2		3		3		2		10
		%	5.3%		7.5%		7,5%		5.0%		6.3%
	don't know	freq.	0		0		8		16		24
		%	0%		,0%		20.0%		40.0%		15.2%
Total		freq.	38		40		40		40		158
		%	100.0%		100.0%		100.0%		100.0%		100,0%
Chi-Square Tests
	Value	d f
Pearson Chi-Square	34.293a	6

Every fourth respondent claimed that he/she had his/her teeth bleached, regardless of gender or faculty. These results suggest that the younger the student population, the more essential esthetics, smile and beautiful teeth are as distinctive facial details (22). One third of patients (34%) would like to whiten their teeth, while the percentage is lower among the population of dental students (28%), which is associated with their education during the study, especially as they progress and receive more information on indications, contraindications and potential side-effects during tooth bleaching procedures (23, 24). If they decided to bleach their teeth, 80% of the subjects would go to their dentist's office rather than use some of ‘over the counter’ bleaching products with statistically significant difference (χ²=10,985, df=3, expected χ²=7,815) (Table 3 and Figure 5, 6).

Table 3. Difference between bleaching treatments.

			FACULTY				Total
			Dental Medicine	Medicine	Economics	Civil Engineering
	Over the counter products	freq.	2	6	11	13	32
		%	5.3%	15.0%	27.5%	32.5%	20.3%
	In-office treatment	freq.	36	34	29	27	126
		%	94.7%	85.0%	72.5%	67.5%	79.7%
Total		freq.	38	40	40	40	158
		%	100.0%	100.0%	100.0%	100.0%	100.0%
Chi-Square Tests
	Value	df
Pearson Chi-Square	10.985a	3

Figure 6.

Frequency of dental visits

Less than half of all subjects (46%) considered that tooth bleaching has potential side-effects, mostly dental students (57%) but with no statistically significant differences between them. In 2010, Hatherell et al. (24) examined dental students in Cardiff, Cork and Malmö. The students in Cork had few hours of education on teeth bleaching, while students in Cardiff and Malmö didn't have any theoretical education on same subject. 76% of students in Cork and less than 70% students in Cardiff and 36% students in Malmö considered tooth bleaching a very safe procedure. Tanalp et al. reported that students considered bleaching of endodontically treated teeth not so effective (23). Many researchers have concluded that tooth bleaching has some negative effects (10, 13, 14, 17, 25, 26) but they stated that it is a safe procedure if performed professionally, under the dentist’s supervision. No clinical studies or case reports in the literature have documented macroscopically or clinically visible damage due to vital bleaching or clinically relevant tissue destruction (17). Tooth sensitivity can occur during or after the bleaching treatment (8, 11, 13) and it is considered a transient painful sensation which usually completely disappears in two to three days (13, 14, 27, 28). Pain and sensitivity can be explained by the irritating effect of hydrogen peroxide on the pulp cells because the molecules of hydrogen peroxide can penetrate to the pulp through enamel and dentin. There, they can cause mild reversible pulpitis which can be manifested as tooth hypersensitivity and intermittent spontaneous pain. Matis et al. found that the sensitivity peaks on the third day of treatment, which is associated with a higher concentration of peroxide radicals inside the pulp (29). Many desensitizing dentifrices contain potassium salts, which are believed to reduce the excitability of the intradental nerves and they should be more effective than tubule-occluding agents such as amorphous calcium phosphate (ACP). On the other hand, ACP may increase the mineral density of enamel hardening (28). Gingival and soft tissue irritation is also a common, but temporary side effect. It is usually related to high concentrations of whitening agents or to long term usage at home and can be avoided by proper soft tissue isolation or by individual tray application (29-31). Clinically, irritation can appear as an ulceration which fades away in a few days. Burgess reported that application of vitamin E directly to the ulceration leads to faster healing (32). Klarić et al. showed that bleaching agents with high concentrations of hydrogen peroxide resulted in a reduction in surface enamel and dentin microhardness while postoperative treatment with ACP demonstrated the increase in surface microhardness, improved surface roughness and enhance the remineralization of the hard dental tissues (17), which was also confirmed by a number of previous studies (33-35). Also, more acid bleaching gels can cause additional alterations in the enamel surface and a low pH of bleaching agents can sometimes be below critical pH for enamel demineralization (16, 33, 34).

It is important to point to possible adverse effect of tooth bleaching and to provide adequate patient preparation with proper clinical examination prior to bleaching. Also, some contraindications should be excluded such as carious teeth, teeth with exposed dentin or teeth with large fillings or those with damaged restorative fillings. Also, every discolored tooth should be tested for potential periapical or pulpal inflammation. Education on good and adequate oral hygiene certainly claims its place as part of primary and secondary education and is the best way to modify the attitude of adults towards oral health. Such education should result in better understanding of other dental procedures such as tooth bleaching or tooth whitening. The results of this study show that further research is needed which would include students of different faculties in order to gain insight into the cultural and socio-economic disparities, not only among students in Croatia but also international students.

CONCLUSION

Having identified the most important limitations to our study, we can conclude that there is a difference in knowledge about oral hygiene and tooth bleaching among the students from the School of Dental Medicine, School of Medicine, the Faculty of Economics and the Faculty of Civil Engineering. As expected, dental students have the best knowledge on tooth bleaching and oral health which was in accordance with their educational guidance and level of education. Information on the mechanism of tooth bleaching, types of bleaching treatments, indications and contraindications and possible adverse effects should be made available to the public. Further studies, with a time delay, for the purpose of comparison and monitoring of knowledge and information about tooth bleaching procedure, especially in the current student population, are required.