Knowledge and Attitudes of a Group of Dental Students in Turkey About Molar Incisor Hypomineralization

Background

Molar incisor hypomineralization (MIH) was first described by Weerheijm et al [1] in 2001 as a developmental enamel defect of systemic origin affecting at least 1 first permanent molar and usually associated with lesions in permanent incisors [2]. Although the etiology is not clear, it is currently thought to be related to genetic factors, environmental factors, diseases and smoking during pregnancy, low birth weight, birth complications, diseases and medications in the first 3 years after birth, and vitamin D deficiency [3–5].

MIH clinically presents as white to yellow-brown opaque lesions with a distinct line between the lesion and healthy enamel. Depending on the severity, teeth with MIH may exhibit rapid wear, enamel loss after enamel breakdown and eruption under functional masticatory forces, increased sensitivity to caries, loss of fillings and, above all, severe sensitivity that often causes serious discomfort [6–11]. In addition, MIH causes a higher risk of caries in children, both in the permanent and primary dentition [12].

Considering several clinical problems that may arise, the clinical management of MIH can be challenging for the dentist [13]. Molars are often hypersensitive and can be difficult to anesthetize [14]; however, post-eruptive enamel breakdown can occur rapidly following eruption and may make teeth more susceptible to caries [15]. In addition to the potential for post-eruptive enamel breakdown in these teeth, MIH-affected enamel has structural differences such as higher protein content and lower mineral density than healthy enamel [16]. This, in turn, leads to poor retentive etching patterns and higher failure rates in adhesive fillings, which, among other factors, makes clinical management of MIH-affected teeth regarding cavity design and material choices a serious issue [17]. As it is a difficult condition for clinicians to manage, it is crucial for clinicians to develop awareness, identification skills, and knowledge of its treatment to provide efficient and high-quality oral health care to those affected [18].

At present, there is a scientific concern that MIH should be included as an essential topic in undergraduate curricula [19]. We suggest that the knowledge and experiences acquired at the undergraduate level are crucial in shaping students’ medical careers, and it is necessary to investigate the knowledge and attitudes of future dentists regarding diagnosis and treatment. For these reasons, this study was conducted to evaluate the knowledge, attitudes, and practices of 4th- and 5th-year dental students about MIH.

Material and Methods

STATISTICAL METHODS:

The data were analyzed with IBM SPSS V23. Yates’ correction and Pearson’s chi-square test were used to compare the responses to the questionnaire questions according to student year and sex, and multiple comparisons were made with the Bonferroni corrected Z test. The results of the analysis are presented as frequencies (percentages). The significance level was set as P<0.050.

Results

A total of 218 4th- and 5th-year dental students from among 259 (4th-year: 137, 5th-year: 122) students participated in our study. The detailed distribution was as follows: 111 4th-year students with 47 women and 64 men (51%) and 107 5th-year students with 46 women and 61 men (49%). Table 1 shows the responses of the participants to the questionnaire according to their year in the order in which they appear in the survey.

A statistically significant difference was found between the distributions of the participants’ having heard the term MIH before (P<0.001). While 68.5% of the 4th-year students had heard of it, 98.1% of the 5th-year students had heard of it. The difference in where they heard about it from was due to the options of dental journals, books, and clinic (P=0.001).

While the rate of those who knew the clinical features of MIH was 55.9% in the 4th-year students, this rate was 89.7% in the 5th-year students (P<0.001). A statistically significant difference was found between the years in terms of distribution of the participants’ knowledge of whether there are clinical criteria for diagnosing MIH (P<0.001). The difference here was observed between those who said “Yes I know the criteria, and I know how to apply them” and those who did not know. In the clinic, 31.5% of the 4th-year students said that they could identify a patient with MIH, whereas this value was 63.6% in the 5th-year students (P<0.001). A statistically significant difference was found between the years in terms of distributions of how confident the participants were in diagnosing MIH (P<0.001). Here, the difference was observed in the rates of those with great confidence, those with confidence, and those with no confidence at all.

While there was no statistically significant difference between the years in terms of difficulty in distinguishing MIH from other dental anomalies, dentinogenesis imperfecta anomaly was found to be statistically significant in the distribution of those who had difficulty in distinguishing it (P=0.007). A statistically significant difference was found between the 4th-year and 5th-year students in terms of how often they noticed teeth with MIH in the clinic (P<0.001). Here, the difference was observed in the distribution of monthly and those who had never noticed.

To the question “Are you aware of the prevalence of MIH in Turkey?”, 14.4% of the 4th-year students answered yes, whereas 30.8% of the 5th-year students answered yes (P=0.006). In the clinic, the rate of those who encountered a significant hypomineralized defect in the permanent teeth other than the first molar and incisors was 40.5% in the 4th-year students and 66.4% in the 5th-year students, and this difference was statistically significant (P<0.001). In the question about the etiology of MIH, a significant difference was observed between years in the option none of the above (P=0.013). Most of the participants who thought that MIH was a clinical problem stated that they had problems with aesthetics. Between the 4th-year and 5th-year students, a statistically significant difference was found in the distribution of those who had problems with both aesthetics and adequate restoration (P=0.012).

The students in both years stated that they mostly used composite resin material in the treatment ol1 f molars with MIH and emphasized the aesthetic factor in material selection.

Discussion

MIH is widely recognized as a clinical challenge for dentists and patients [17]. Severe MIH can affect quality of life and oral function in children [23]. If left untreated, after 2 years, molars affected by mild MIH can progress to moderate or severe MIH with enamel breakdown [24]. Developing countries bear most of the global burden of MIH [25]. If preventive measures are not taken, the cost of treating MIH will be very high for countries and individuals [26]. Therefore, it is important to study the etiology, treatment, and awareness of MIH, and the curricula of universities, especially in developing countries, must keep pace with this growing challenge and provide future dentists with the necessary training to deal with this problem.

The importance of this research is that it assessed the inadequacies of dental students on this subject and our results can be used to increase their awareness. There has been great interest in MIH in many countries, and surveys for dentists have been conducted [27–29]. In Indonesia, Switzerland, Austria, Syria, and Germany, students’ knowledge on this topic was specifically assessed [20–22,30,31]. To the best of our knowledge, this is the first study to examine the knowledge and attitudes of dental students in Turkey about MIH.

When the results of this cross-sectional study were analyzed, it was found that students generally have heard the term MIH, but 5th-year students were more familiar with it. In similar studies conducted in Austria, Egypt, Germany and Switzerland [20–22,32], it was reported that most students were familiar with MIH, but in a study conducted in Saudi Arabia, 64% of students had not heard the term MIH [33]. This may be related to the fact that the studies were conducted at different times. MIH, which has a history of 20 years, has become more publicized over time. When we evaluated where they heard the term MIH, lectures are the primary sources of knowledge in many countries [20,21,31], which is compatible with our study. MIH is included in the curriculum of the university where this study was conducted. It is explained to the students theoretically in the 3rd-year pediatric dentistry course.

According to the research at King Saud University in Riyadh, it was reported that 35% of the 4th-year students and 25% of the 5th-year students knew the clinical features of MIH [33], whereas in our study, these rates were 68% and 98%, respectively. It was observed that the level of students’ knowledge about the clinical features of MIH increased as their education progressed. Our results are in line with studies conducted in other countries [21,22,34].

While most of the students who participated in the present study stated that they were somewhat confident in diagnosing MIH, the number of students who chose the option of being very confident was quite low, in line with the results of a similar study conducted in Germany [21]. In a similar study conducted among dentists in Kuwait, 72% of general dentists reported that they were not confident, similar to our study [35].

With regard to this study’s results, all of our students stated that they had difficulty in distinguishing MIH from other dental anomalies, as in similar studies [18,31]. In a study conducted at the University of Nevada School of Dentistry in Las Vegas [18], postdoctoral dentists reported that they most often confused it with fluorosis, followed by amelogenesis imperfecta, whereas in a similar study in Syria [31], senior dental students reported that they had the most difficulty distinguishing it from amelogenesis imperfecta and enamel hypoplasia. In our study, the 4th-year students stated that they confused it with amelogenesis imperfecta and enamel hypoplasia and the 5th-year students confused it with enamel hypoplasia and amelogenesis imperfecta, respectively. These differences between studies may be due to the participants’ pre- and postgraduation status.

In a study conducted in Istanbul, the prevalence of MIH was found to be 14.2%, the same level as the global prevalence of MIH found by Zhao et al in 2018, and they concluded that it was a common condition [36,37]. However, most of the students who participated in the present study reported that they were not aware of the prevalence of MIH and that it would be worth investigating. However, both the 4th-year and 5th-year students stated that the prevalence of MIH in Turkey is less than 25%, which is consistent with the prevalence in these studies.

Most of the participants encountered significant hypomineralized defects in permanent teeth, except for the first molars and incisors. This is consistent with the findings of the study conducted by Skaare et al [27]. However, in their study, these defects were mostly encountered in permanent canine teeth, whereas in our study, these defects were mostly encountered in premolars by the 4th-year students and in the second molars followed by premolars by the 5th-year students. In a study conducted in Australia and Chile, MIH-like defects were mostly encountered in premolar teeth [38].

A study conducted by Hussein et al in Malaysia reported that the most common defects encountered by dental nurses were yellow/brown defects, whereas white defects were more often encountered by general practitioners [39]. In similar studies, it was reported that yellow/brown defects were encountered most frequently [27,38]. In the present study, the most common defect encountered by the 4th-year students was white defect (38.7%), whereas yellow/brown defect (47.7%) was more often encountered by 5th-year students. The prevalence of defects with enamel loss was low in both years, and the defect may have been masked by extensive caries or atypical restorations.

When questioned about the etiology of MIH, most of the 4th-year and 5th-year students indicated they thought it was genetic. In a study conducted at Wuhan University School of Stomatology, the 4th-year students emphasized genetics (87%) and pregnancy and postnatal factors (87%), whereas 87% of the 5th-year students reported genetics as the etiology [34]. In studies conducted in Egypt and Greece, similar to the present study, participants stated that genetics was the most important etiology [32,40].

In a similar study conducted in Syria, the senior dental students stated that they had the most difficulties in the long-term success of restoration and diagnosis [31]. In a study conducted in Greece, they reported that they most frequently had problems with aesthetics [40]. Most students who participated in our study reported that MIH is a clinical problem. Both the 4th-year and 5th-year students had the most problems with esthetics, but they also frequently reported problems with diagnosis, providing adequate restoration, and determining the cavity boundaries of the affected enamel.

Serna-Muñoz et al found that most participants preferred resin-modified glass ionomer cement for the treatment of post-eruption fractures and opacities, whereas they preferred composite resin for hypomineralized incisors [41]. In the study of Hamza et al in Syria, the senior dental students reported that they preferred stainless steel crowns (40.6%) and composite (40%) in the treatment of molars with MIH [31]. In the present study, similar to the results of Bekes et al and Gamboa et al, composite resin was the preferred material for treatment of teeth with MIH [22,42]. The students who participated in the present study also based their choice of materials on esthetic factors, as in the study by Yehia et al [32].

Since this study was limited to dental students in a single university, it cannot be generalized to the current knowledge on MIH of the overall population in Turkey. There is a need for studies with larger samples by including dental faculties of other universities. In fact, a similar questionnaire study can be applied to postgraduate dentists and the results can be compared. Another limitation of the study is that the questionnaire was presented to the students online; therefore, they could look up the information before answering, especially given that internet access is widely available and they are aware that their answers will be used for research or other purposes.

Conclusions

Although most of the students were theoretically familiar with MIH, they were not confident in diagnosis and found it difficult to differentiate MIH from other dental anomalies, but the awareness of 5th-year dental students was better than that of the 4th-year students. Nevertheless, MIH warrants greater emphasis in the theoretical and practical dental curricula.