Introduction
The term “Molar-Incisor Hypomineralization” (MIH) was first proposed by Weerheijm et al. in 2001 to describe well-demarcated enamel hypomineralization defects affecting at least one first permanent molar, often accompanied by the involvement of permanent incisors[1]. The European Academy of Pediatric Dentistry subsequently recognized MIH as a clinically significant condition in pediatric dentistry and suggested that clinicians should consider a range of associated indicators, such as post-eruptive enamel breakdown, hypersensitivity, atypical restorations, and elevated caries risk, when making a diagnosis[2].
If not identified early, MIH may lead to substantial structural damage, repeated restorative failures, and increased long-term treatment needs, underscoring the importance of an early and accurate diagnosis in pediatric dental practice[3]. Owing to structural defects in the enamel, breakdown of the enamel and secondary caries commonly occur soon after an eruption. This can cause pain and dental fear, significantly impairing a child’s oral health-related quality of life[4,5]. A recent systematic review and meta-analysis has identified dental caries (51.2%), tooth hypersensitivity (41.7%), and post-eruptive enamel breakdown (25.7%) as the most common clinical outcomes in MIH patients, highlighting the substantial clinical burden associated with MIH[6]. Globally, approximately 878 million people are estimated to be affected by MIH, with around 17 million new cases diagnosed annually[7]. The global average prevalence of MIH is reported to be approximately 15.5%[8], with regional prevalence rates in Korea reported as high as 13.8%[9-11]. Although the etiology of MIH remains unclear, it is presumed to involve complex factors such as genetic predisposition and systemic health conditions during prenatal and immediate postnatal periods, antibiotic usage, and environmental toxins[12,13].
Despite the clinical importance of early detection and accurate diagnosis, MIH remains a diagnostic challenge because of its diverse clinical manifestations and the difficulty in differentiating it from similar conditions[14]. While dental students and early-career clinicians may be relatively familiar with the concept of MIH, their ability to apply diagnostic criteria accurately and make appropriate clinical decisions appears limited[15-18]. Indeed, international studies have consistently reported that dental practitioners experience clinical uncertainty when diagnosing MIH, attributing this to the absence of clear diagnostic guidelines and limited cumulative clinical experience[19-21].
In Korea, discussions on the diagnostic challenges and educational gaps related to MIH remain insufficient, and research on diagnostic competence and related educational systems in dental schools remains limited. These educational shortcomings may delay early diagnosis and optimal intervention, leading not only to repeated treatment burdens, but also to psychological distress in pediatric patients[22].
Therefore, the present study aimed to investigate the levels of awareness and understanding of diagnostic criteria, self-reported diagnostic capacity, and educational needs regarding MIH among dental students and residents of Chonnam National University School of Dentistry. These findings are intended to inform the current status of MIH diagnostic education and contribute to the development of an integrated educational framework involving interdisciplinary collaboration.
Materials and Methods
1. Study Design
This study was designed as a descriptive cross-sectional survey conducted between September and October 2024 at Chonnam National University School of Dentistry. The data were collected using structured questionnaires. Ethical approval for the study was obtained from the Institutional Review Board of Chonnam National University Dental Hospital (Approval No. CNUDH-2025-002) to ensure the ethical validity of the study. All participants received explanations of the study’s objectives and provided informed consent, with participation remaining entirely voluntary. All invited participants received an identical coffee coupon regardless of participation, minimizing perceived pressure or disadvantage. The survey was conducted anonymously, collecting only participants’ academic year for students and specialty and training year for residents, with no other personal information collected.
2. Participants and Sample Size Calculation
The study population included third- and fourth-year dental students at Chonnam National University School of Dentistry, and residents and interns affiliated with Chonnam National University Dental Hospital. The required sample size was calculated using the G*Power 3.1 software (Heinrich Heine University Düsseldorf, Düsseldorf, Germany), with an effect size of 0.5, an alpha level of 0.05, and a statistical power (1-β) of 0.85, resulting in a minimum required sample of 70 participants each for the student and resident groups. Actual data were collected from 145 students and 74 residents, totaling 219 participants. For data analysis, survey responses were initially compared between third- and fourth-year dental students, followed by comparisons among residents based on training year and specialty (pediatric/restorative dentistry residents vs. residents from the other dental specialties). Additionally, responses from all students and all residents were compared.
3. Survey Instrument and Structure
The questionnaire was developed based on a previous study by Gambetta-Tessini et al.[23], and was designed to comprehensively assess knowledge, perceptions, clinical experience, and educational needs regarding MIH. A pilot test involving ten third-year dental students was conducted to assess content validity, comprehension, and answer distribution. Based on their feedback, minor revisions were made to improve clarity and consistency, and a final version was established. The final questionnaire consisted of 28 items across five domains: awareness of MIH, knowledge of prevalence and etiology, clinical observation and diagnostic confidence, clinical perception, and recognition of clinical importance and educational needs (Table 1 ‒ 3). Additionally, one image-based identification question to select the MIH lesion was included (Fig. 1). The ten students who participated in this pilot test were not included in the final study sample.
The visual diagnostic question included clinical images of MIH and conditions requiring differential diagnosis (enamel hypoplasia and white spot lesion), presented as a four-option multiple-choice question. These specific conditions were selected because they are frequently confused with MIH in clinical practice due to their overlapping morphological features[24], as well as their relatively higher clinical prevalence compared to rare conditions such as amelogenesis imperfecta. High-resolution clinical images focusing on MIH lesions were selected by consensus of two pediatric dentistry specialists. For standardization of image, all photographs were captured under identical conditions of lighting, distance, and angle, and backgrounds were adjusted to exclude extraneous elements such as lips or tongue. To verify the objectivity of correct answers, two additional pediatric dentistry specialists independently evaluated this question, achieving complete agreement with a Cohen’s kappa coefficient of 1.00.
4. Statistical Analysis
All statistical analyses were performed using SPSS Statistics version 29.0 (IBM Corp., Armonk, NY, USA). Categorical variables were analyzed using the chi-squared test or Fisher’s exact test, while continuous variables were compared between groups using independent t-tests or one-way analysis of variance (ANOVA). Univariate logistic regression analyses were conducted to identify potential predictors. As none of the variables demonstrated statistical significance (p < 0.05), multivariate analysis was not performed. Statistical significance was set at α = 0.05, and effect sizes were assessed using Cohen’s h, Cohen’s d, Cramér’s V, and partial eta squared (η²), depending on the data type and statistical test used. Statistical comparisons were not performed for multiple response items, as these did not represent mutually exclusive categories.
Results
1. Students’ Awareness, Clinical Experience, and Educational Needs Regarding MIH
In this survey, students’ overall familiarity with MIH was relatively high at 69.0%, but only 3.4% of students reported knowing and being able to clinically apply the actual diagnostic criteria (Table 1). Most students were unaware of the precise national prevalence of MIH, though genetic factors were most frequently identified as etiological factors. Other selected etiological factors included maternal medication use, maternal medical conditions, and childhood medication use (Table 1). Only 17.2% of all students had clinical experience observing MIH patients (Table 2). The frequency of encountering MIH teeth in clinical practice was significantly higher among fourth-year students (36.3% annually) compared to third-year students (16.9%, p= 0.021), indicating increased clinical exposure with academic progression (Table 2). A total of 89% of students reported difficulty distinguishing MIH from other dental conditions, with third-year students (96.9%) significantly more likely to report difficulty than fourth-year students (82.5%, p= 0.006), implying greater confusion among junior students due to limited diagnostic experience (Table 2). Finally, most students perceived MIH as a clinically important issue and recognized the need for additional education, particularly preferring case-based practical sessions (Table 2, 3).
2. Comparison of Students’ and Residents’ Awareness, Clinical Experience, and Educational Needs Regarding MIH
Compared to students, residents demonstrated significantly higher familiarity with MIH, awareness of clinical features, and knowledge of diagnostic criteria (Table 4, each p < 0.0001). Residents also reported significantly higher clinical observation of MIH patients (p < 0.0001) and greater ability to identify MIH in practice (p= 0.010). Additionally, residents showed significantly higher diagnostic confidence (p < 0.0001) and greater accuracy in image-based MIH identification (p= 0.014).
3. Residents’ Awareness, Clinical Experience, and Educational Needs Regarding MIH
Residents exhibited high familiarity with MIH across all training years (Table 5). The proportion of residents who reported knowing and being able to clinically apply the diagnostic criteria increased significantly with advancing training year (Table 5, p= 0.006). Additionally, while residents showed an increasing trend in their reported ability to clinically identify MIH patients and fewer difficulties with differential diagnosis as their training year advanced, these trends were not statistically significant (Table 6). There were significant differences by training year in diagnostic confidence, which increased with advancing training year (p= 0.006), and in perceiving MIH as a clinical problem (p= 0.002, Table 6). Most residents indicated a need for expanded MIH education within dental school curricula, especially preferring case-based practical sessions (Table 7).
Residents specializing in pediatric dentistry and restorative dentistry demonstrated significantly higher awareness of clinical features (p= 0.03), diagnostic criteria (p < 0.0001), and associated caries patterns of MIH (p < 0.0001) compared to residents in the other specialties (Table 8). Frequency of clinical MIH observations (p < 0.0001) and reported ability to identify MIH patients (p < 0.0001) were also significantly higher. Additionally, pediatric and restorative dentistry residents reported significantly higher diagnostic confidence scores (p= 0.001) and awareness of the importance of early intervention (p= 0.001). Both groups showed similarly high agreement on the necessity of additional MIH education, with no significant difference.
4. Accuracy of Image-Based MIH Identification and Related Factors
In the image-based MIH identification question, students achieved an overall correct answer rate of 54.5% (Table 3), with incorrect answers primarily involving confusion with white spot lesions of early caries (31.7%) and enamel hypoplasia (19.3%). The resident group showed a higher accuracy rate of 71.6% (Table 7), although incorrect answer patterns were similar to those of students (white spot lesions 21.6%, enamel hypoplasia 10.8%). Considering that both groups most frequently confused MIH lesions with white spot lesions, distinguishing between MIH and early caries lesions is a common clinical challenge.
Logistic regression analysis revealed that academic year, resident training year, clinical awareness of MIH, clinical observation experience, and self-reported diagnostic confidence did not significantly predict accuracy in image-based MIH diagnosis (Table 9). Additionally, although a significant difference in self-reported diagnostic confidence scores was observed between correct and incorrect respondents on the image identification question (p= 0.029), the small effect size (Cohen’s d = 0.30) limits clinical significance (Table 10). These findings suggest that image-based MIH diagnostic ability is not solely determined by educational year, clinical experience level, or self-reported diagnostic confidence, highlighting the need for educational strategies incorporating more objective assessment methods.
5. Association Between MIH Diagnostic Confidence, Knowledge of Diagnostic Criteria, and Clinical Experience
In the combined analysis of students and residents, diagnostic confidence scores differed significantly according to knowledge of MIH diagnostic criteria, clinical observation experience, and frequency of lesion observation (Table 10). Respondents who knew the diagnostic criteria and those with clinical observation experience both demonstrated significantly higher diagnostic confidence, with similarly large effect sizes observed for both factors. These results suggest that both knowledge of diagnostic criteria and clinical exposure are critical factors influencing diagnostic confidence.
Discussion
In this study, dental students at Chonnam National University School of Dentistry demonstrated relatively high overall familiarity with MIH; however, only a small proportion reported knowing and being able to clinically apply the diagnostic criteria (Table 1). This finding suggests that rather than reflecting individual students’ lack of effort, the dental education curriculum might overly emphasize theoretical instruction, providing limited exposure to actual clinical cases. Additionally, despite fourth-year students having greater exposure to MIH cases compared to third-year students, both cohorts reported substantial difficulties distinguishing MIH from similar dental conditions (Table 2), suggesting that increased case observation alone does not automatically translate into improved diagnostic skills. Moreover, most students recognized the need for additional MIH-related education, which likely reflects their awareness of the limitations in their current training and low diagnostic confidence (Table 3).
Compared with European countries such as Germany, Switzerland, Austria, and Spain, students in this study reported relatively lower MIH awareness (69.0%) and less clinical observation of MIH (17.2%), highlighting notable gaps in practical training opportunities (Table 11). Nevertheless, students in these European countries[25-28] also identified limitations including lecture-centered MIH education and insufficient clinical practice, indicating that difficulties in distinguishing MIH from similar dental conditions represent a universal challenge in dental education internationally. Additionally, diagnostic confidence was generally low across most regions, except for Spain, implying potential differences in educational strategies and their impact on student self-assessment.
Recently, Humphreys et al.[29] investigated undergraduate MIH education in 16 dental schools in the United Kingdom. Their findings revealed that most dental schools provided fragmented MIH education primarily within pediatric dentistry departments, with inadequate interdisciplinary cooperation and integrated education involving orthodontics, conservative dentistry, and the other specialties. This fragmentation raised concerns about variability in students’ clinical competence and patient management capabilities.
In this study, significant differences emerged between students and residents regarding their awareness of MIH clinical features, knowledge of diagnostic criteria, and accuracy of image-based diagnosis (Table 4). Although these differences are expected due to varying levels of clinical experience, it is noteworthy that the gap between theoretical knowledge and clinical applicability persisted even among residents, suggesting that diagnostic competence issues identified among students remain unresolved during residency training.
Dental residents demonstrated high overall familiarity with MIH (98.6%), but only 17.6% reported knowing and being able to clinically apply the diagnostic criteria, indicating a substantial discrepancy between their theoretical knowledge and clinical performance (Table 5). More than half of the residents (56.8%) reported no clinical experience observing or diagnosing MIH patients (Table 6). Even residents who encountered MIH during undergraduate education might enter residency training with theoretical knowledge primarily oriented toward national licensing examinations, lacking direct clinical diagnostic experience. Additionally, residents from specialties other than pediatric and restorative dentistry may have limited opportunities to receive consistent and detailed clinical feedback on MIH, further increasing diagnostic uncertainty. Moreover, potential confusion between MIH and other enamel defects—such as dental fluorosis, amelogenesis imperfecta, and white spot lesions—often makes differential diagnosis challenging, a difficulty consistently reported by clinicians worldwide[30]. Taken together, these multifactorial issues may explain why residents’ high theoretical familiarity with MIH does not fully translate into clinical competence.
Furthermore, most residents (82.4%) reported difficulty distinguishing MIH from other enamel defects, and exhibited low diagnostic confidence (mean score 2.28 out of 5, Table 6), underscoring ongoing challenges in clinical application. In addition, perceptions regarding the importance of early intervention varied significantly by training year (Table 7), with higher importance assigned by third- and first-year residents. This irregular trend may reflect differences in clinical exposure, educational experiences, individual motivation, or residency program structures, although further research is needed for clarification.
In this study, residents in pediatric and restorative dentistry demonstrated significantly higher understanding of MIH clinical features, diagnostic criteria, and related caries patterns compared to those from the other specialties. The most notable difference was observed in the reported knowledge of diagnostic criteria (45.0% vs. 7.4%, p < 0.0001), likely reflecting differences in curriculum structure and clinical exposure between specialties (Table 8). First, pediatric and restorative residents have more frequent clinical encounters with MIH patients, enabling greater accumulation of case experience. Second, their residency programs provide structured diagnostic training through regular seminars and case presentations supervised by specialists, facilitating continuous clinical exposure to MIH cases. Similarly, Negrescu et al. emphasized structured clinical case analysis and regular, intensive diagnostic training as key factors for enhanced diagnostic accuracy among pediatric residents[31]. Lastly, pediatric and restorative residents tend to participate more frequently in external educational activities, such as conferences, seminars, and workshops, providing consistent exposure to the latest diagnostic criteria, restorative guidelines, and clinical approaches.
Although pediatric and restorative dentistry residents reported higher diagnostic confidence than residents from the other specialties, their overall self-assessed confidence remained relatively low (Table 8). Previous studies by Eva and Regehr[32] and Fraundorf et al.[33] suggest this might reflect metacognitive tendencies, as highly skilled clinicians tend to evaluate their own performance more critically and strictly. Thus, this metacognitive factor might partly explain the discrepancy between their theoretical knowledge and self-perceived diagnostic confidence.
These findings underscore the need for longitudinal and structural diagnostic training from undergraduate through residency levels to reduce diagnostic confusion and improve MIH diagnostic accuracy. In this study, image-based diagnostic accuracy was not significantly predicted by training year, clinical exposure, or self-reported confidence (Table 9), indicating that conventional educational milestones may not adequately capture diagnostic competence. However, diagnostic confidence was significantly associated with knowledge of diagnostic criteria and clinical observation experience (Table 10), demonstrating the potential value of targeted, experience-based instruction.
Diagnostic errors in MIH can negatively affect treatment planning and long-term prognosis management[ 34]; thus, consistent and structured education is crucial to build diagnostic confidence[35]. Particularly, mild MIH lesions may remain unnoticed by patients[36], reducing clinical training opportunities. Given the potential impact of MIH on orthodontic or restorative treatments beyond childhood[37], interdisciplinary education at the undergraduate level should be emphasized in similar dental educational settings.
Accordingly, a stepwise, integrated curriculum could be considered to enhance MIH diagnostic competence, while carefully accounting for institutional differences. Initially, theoretical education on clinical features, diagnostic criteria, and management strategies can be introduced or reinforced in the earlier academic years. Subsequently, practical training and case-based MIH exposure can be expanded through structured sessions or digital platforms, depending on available clinical resources. Small-group case discussions facilitated by faculty and peer feedback can further support students’ diagnostic skills and clinical reasoning. Interdisciplinary seminars involving pediatric dentistry, orthodontics, and restorative dentistry might promote integrated management approaches among dental students and residents, adapted according to each institution’s specific educational environment.
Moreover, incorporating selected digital educational tools could enhance MIH diagnostic training and evaluation. For example, standardized image-assessment systems and Artificial Intelligence (AI)-based training platforms might objectively assess lesion characteristics and improve diagnostic accuracy[38-40]. Virtual reality simulations and interactive digital modules could further support realistic clinical training and self-directed learning[41,42]. Peer assessment methods using standardized rubrics might also serve as complementary objective evaluation tools, fostering critical thinking and reflective learning[43]. Ultimately, collaboration among dental schools and relevant academic societies, led by the Korean Academy of Pediatric Dentistry, could facilitate the development of evidence-based MIH guidelines adapted to individual educational contexts.
This study has several limitations. First, as a single-institution study conducted among dental students and residents at Chonnam National University School of Dentistry, the findings may not be broadly generalizable to all dental education settings in Korea. Additionally, discrepancies in sample sizes between students and residents could affect the reliability and validity of statistical analyses, requiring cautious interpretation. Clinical exposure differences among residents from various specialties also need consideration, as these could influence diagnostic competence independently of educational interventions.
Second, the self-report survey method inherently involves subjective assessments, introducing possible respondent biases and limiting objective evaluations of actual clinical competence. Although the questionnaire used was based on internationally recognized items, self-assessments alone have inherent limitations in verifying actual clinical competence. Furthermore, employing only a single-image diagnostic assessment per item may not adequately represent the broad spectrum of MIH clinical presentations, thus limiting diagnostic accuracy and objectivity. Future studies should utilize multiple standardized clinical images and structured diagnostic assessments, such as image-based or AI-supported methods, to enhance reliability.
Lastly, to overcome these limitations and enhance the generalizability of findings, designing a multicenter collaborative study is recommended[44]. For practical implementation in Korea, establishing a research consortium and standardizing study protocols would minimize inter-institutional variability, providing more robust and generalizable findings.
To our knowledge, this study is the first to comprehensively investigate MIH awareness and educational needs among dental students and residents in Korea, including direct comparisons across training levels and specialties. These distinctive aspects may provide useful insights for further discussion and potential improvements in dental education.
Conclusion
This study investigated dental students’ and residents’ awareness, diagnostic experience, and educational needs regarding MIH at Chonnam National University School of Dentistry. The findings revealed generally low self-perceived understanding and diagnostic confidence, suggesting that theoretical knowledge alone may not sufficiently lead to confidence in clinical application. Given that diagnostic errors in MIH can significantly impact patient prognosis, practice-oriented educational strategies and objective evaluation systems are needed.
PDF Links
PubReader
ePub Link
Full text via DOI
Download Citation
Print
