Prevalence and Clinical Patterns of Molar-Incisor Hypomineralisation and Hypomineralised Second Primary Molars among Children with Special Healthcare Needs: A Comparative Cross-Sectional Study

Prevalence and Clinical Patterns of Molar-Incisor Hypomineralisation and Hypomineralised Second Primary Molars among Children with Special Healthcare Needs: A Comparative Cross-Sectional Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Prevalence and Clinical Patterns of Molar-Incisor Hypomineralisation and Hypomineralised Second Primary Molars among Children with Special Healthcare Needs: A Comparative Cross-Sectional Study Ishwarya Shanmugam, Arulpari M, Selvakumar Haridoss, Priya Jayakumar, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8347247/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Purpose: Developmental enamel defects, commonly seen in children, have proven to pose clinical challenges for pediatric dentists. Among these, Molar-Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) are among the most common enamel defects and each of these has important clinical implications. Children with special healthcare needs (CSHCN) may be more likely to have developmental enamel defects due to systemic, perinatal & environmental factors. The aim of this study was to assess and compare the prevalence, distribution and clinical patterns of molar-incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPM) in children with special healthcare needs and neurotypical children aged 7–13 years. Methods: A comparative cross-sectional study was conducted among 216 children (108 neurotypical children and 108 CSHCN) by a calibrated examiner following the EAPD Diagnostic criteria for MIH/HSPM. Prevalence, severity and lesion extension of MIH and HSPM were noted. Data was analysed using the Chi-square test (p < 0.05 considered statistically significant). Results: The overall prevalence of MIH was 19.4%. MIH prevalence was greater in CSHCN (30.6%) than neurotypical children (8.3%). HSPM prevalence was 4.2% and showed no significance. Severity of MIH was greater within the CSHCN group with 42.1% having atypical caries and 15.8% showing post-eruptive breakdown due to MIH compared to neurotypical peers. Lesion extension was also greater in CSHCN. In CSHCN, most cases involved only molars (84.8%) while neurotypical children showed more molar-incisor involvement. Conclusion: Children with special healthcare needs have a significantly greater prevalence and severity of MIH. These findings emphasize the need to implicate early preventive strategies, proper parental awareness and timely intervention, thereby improving the overall well-being and quality of life in such individuals. children with special healthcare needs developmental enamel defects good health and well-being hypomineralised second primary molars molar-incisor hypomineralisation neurodevelopmental disorders pediatric dentistry Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. INTRODUCTION Tooth formation can be impacted by a variety of genetic and environmental factors both during and after birth (Alaluusua 2010 ). Enamel is a type of tissue that does not have the ability to remineralize, making it susceptible to structural changes resulting from systemic disturbances in the amelogenesis process (Emmatty et al. 2020 ). The term molar incisor hypomineralisation (MIH) refers to hypomineralisation of systemic origin that manifests as distinct, qualitative defects of the enamel of one to four first permanent molars (FPMs) and are often associated with incisors (Weerheijm K et al. 2003 ). The severity ranges from mild, demarcated opacities to post-eruptive enamel breakdown (PEB) which can lead to problems in aesthetics and hypersensitivity adversely affecting the quality of life (Silva et al. 2016 ). The presence of hypomineralised second primary molars (HSPM) serves as an indicator for Molar-Incisor Hypomineralisation (MIH), with a greater prevalence of MIH correlated to the presence of mild HSPM. These conditions exhibit a similar clinical presentation to MIH, mostly due to overlapping periods of amelogenesis (Singh et al. 2020 ). Molar-incisor hypomineralisation is widely prevalent, with rates ranging from 2.4% to 40.2% (Jälevik 2010 ). In India, the estimated prevalence of MIH is around 10.0% (Shetty et al. 2022 ). The observed wide range in prevalence rates can be attributed to variations in indices and age demographics (Yannam 2016). The limited awareness regarding MIH and HSPM may lead to various clinical findings that remain unnoticed, resulting in biased diagnoses and potentially affecting treatment options. Compared to their counterparts without the condition, children with MIH are at an increased risk of dental caries. Children with special health care needs (CSHCN) present with physical, developmental, mental, sensory, behavioural, cognitive, or emotional impairment or limiting condition requiring medical management. This condition can be congenital, developmental, or acquired through disease, trauma, or environmental factors, and it restricts their ability to carry out daily activities (American Academy of Pediatric Dentistry 2025 ). Prior research has indicated variable prevalence of enamel developmental defects in children with special health care needs (Aarthy and Kumar 2020 ; Lin et al. 2011 ). The children under this category may frequently present with medical complications peri and postnatally, which can elevate the risk of hypoxia. These hypoxic conditions can invariably affect the process of amelogenesis leading to such enamel defects. Evidence regarding the prevalence of developmental defects of enamel in children with special healthcare needs has been documented. However, there have been sparse studies assessing the prevalence of MIH and HSPM in such groups. Hence, the purpose of this comparative, cross-sectional study is to evaluate the prevalence of MIH and HSPM and to assess whether children with special health care needs (CSHCN) have a higher risk of MIH and HSPM than neurotypical children aged 7–13 years, by estimating and comparing prevalence, severity, distribution, and age-specific patterns. 2. METHODS 2.1 Study Design and Setting This cross-sectional study was performed on children aged 7 to 13 years. The study population was divided into two groups: children with special healthcare needs (CSHCN) and neurotypical children as the control group. A total of 216 children were examined, comprising 108 neurotypical children as control group and 108 children with special healthcare needs. The neurotypical children who reported to the outpatient department of the Department of Pediatric and Preventive Dentistry at Sri Ramachandra Dental College and Hospital, Chennai and Department of Paediatrics, Sri Ramachandra Hospital were examined, whereas the CSHCN group was selected from several special schools in Chennai. The study was conducted from April to June 2025. Ethical clearance was obtained from the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education and Research (CSP-III/25/FEB/17/103). Written informed consent was obtained from the parents or guardians of all participants wherever possible, and written assent was obtained from neurotypical children before clinical examination. Prior consent was obtained from the schools for children with special healthcare needs for conducting the study. 2.2 Inclusion and Exclusion Criteria The study included children aged 7 to 13 years who had at least one erupted first permanent molar for diagnosis of MIH and second primary molars for HSPM. Children exhibiting generalized developmental enamel defects, including amelogenesis imperfecta or fluorosis, as well as those with syndromic conditions that affect the dentition, were excluded. Children who were uncooperative or whose parents did not give permission were also excluded. 2.3 Sample Size Calculation Sample size was calculated using the formula as shown in Fig. 1 Where, ͞p = P 1 + P 2 / 2 P 1 = Proportion in first group P 2 = Proportion in first group α = Significance level 1-β = Power of the study G*Power software version 3.1 was used for a chi-square test comparing the proportions between CSHCN and neurotypical children groups. The power of the study was set at 80% and an effect size of 0.28 to derive a minimum size of 78 per group. The final sample size of 216 (108 neurotypical and 108 CSHCN) was finalized after considering the potential exclusions due to ineligibility or non-cooperation. 2.4 Clinical Examination All examinations were carried out by a single trained and calibrated examiner under natural daylight using sterile mouth mirrors and straight probes, with additional illumination provided when necessary. The diagnostic criteria recommended by the European Academy of Paediatric Dentistry (EAPD), 2003 were employed to identify MIH and HSPM based on the criteria described by Ghanim et al. (Lygidakis et al. 2021 ). Children were considered to be affected by MIH if one or more PFMs were involved with or without permanent incisor involvement. The clinical 2.5 Examiner Calibration The examiner underwent calibration before the study under the supervision of an experienced pediatric dentist. Intra-examiner reliability was assessed by re-examining 20 children at an interval of two weeks, and the results were compared using Cohen’s kappa statistic. A kappa value of 0.82 was obtained, indicating almost perfect agreement and confirming the reliability of the examiner in diagnosing MIH and HSPM. Data were recorded in a structured proforma noting the presence, severity and lesion extension of MIH and HSPM. 2.6 Statistical Analysis The collected data were entered into Microsoft Excel and descriptive and inferential statistics were analysed using IBM Statistical Package for the Social Sciences (SPSS) software version 30.0 (IBM Corp. Released 2024. IBM SPSS Statistics for Windows, Version 30.0. Armonk, NY: IBM Corp). Frequency and Percentage were used to summarize the qualitative data. Chi-square test was used for comparison of prevalence data between Neurotypical and CSHCN. A p value of ≤ 0.05 was considered as statistically significant difference. 3. RESULTS A total of 216 children, comprising 108 neurotypical children and 108 children with special healthcare needs (CSHCN), aged 7 to 13 years, 114 males and 102 females, were included in the study. After collecting the records from school, we investigated children with behavioural disorders such as autism spectrum disorder and attention-deficit hyperactivity disorder, cognitive disorders such as intellectual disability, developmental disorders like cerebral palsy, and congenital disorders such as Down syndrome. Among the 107 CSHCN, 30 (27.8%) presented with intellectual disability (ID), 20 (18.5%) with autism spectrum disorder (ASD), 19 (17.6%) with ADHD. Less commonly prevalent conditions were global developmental delay (6.5%, n = 7), cerebral palsy (5.6%, n = 6), mental retardation (0.9%, n = 1) and 17 children presented with multiple disabilities (n = 15.7%). 3.1 Age Group Distribution In the neurotypical group, the majority of children (54.6%, n = 59) were between 7–9 years of age, while 28.7% (n = 31) were 10–11 years and 16.7% (n = 18) were 12–13 years. In contrast, CSHCN were more evenly distributed, with 30.6% (n = 33) in the 7–9-year group, 25.9% (n = 28) in the 10–11-year group, and a higher proportion (43.5%, n = 47) in the 12–13-year group. The difference in age distribution between the two groups was statistically significant (χ² = 20.43, p < 0.001) as given in Table 2. The graph is shown in Fig. 5. 3.2 Gender distribution The CSHCN group had a higher proportion of males (56.5%; n = 61) than females (43.5%; n = 47). In the neurotypical group, females constituted 50.9% (n = 55) of the sample, while males accounted for 49.1% (n = 53). The gender difference between the two groups was statistically significant (χ² = 7.45, p = 0.006), indicating that males were disproportionately represented among the two groups (Table 2). 3.3 Prevalence of MIH and HSPM The overall prevalence of MIH was 19.4%. Among neurotypical children, the prevalence of MIH was 8.3% (n = 9), while in CSHCN it was significantly higher at 30.6% (n = 33). The difference was statistically significant (χ² = 17.025, p < 0.001). The prevalence of HSPM was 6.5% (n = 7) in neurotypical children and 1.9% (n = 2) in CSHCN. This difference was not statistically significant (χ² = 2.89, p = 0.170). Figure 6A and 6B shows the prevalence of MIH and HSPM. Table 1 shows the frequency of MIH in different conditions. Table 1 Descriptive data of frequency of MIH in different conditions among CSHCN Type of disability MIH Present Intellectual disability (n = 30) 7 (6.5%) Autism spectrum disorder (n = 20) 6 (5.6%) Attention-deficit hyperactivity disorder (n = 19) 3 (2.8%) Global developmental delay (n = 7) 4 (3.7%) Cerebral palsy (n = 6) 1 (0.9%) Down syndrome (n = 8) 6 (5.6) Multiple disabilities (n = 17) 6 (5.6%) Prevalence of HSPM was rare within the CSHCN population. Only two children (1.8%, n = 2) presented with HSPM, which was observed in children with cerebral palsy. Table 2 Distribution of gender, age groups, and prevalence of MIH and HSPM among children with special healthcare needs (CSHCN) and neurotypical controls Group CSHCN Controls N % N % p-value Gender Female 47 43.5 55 50.9 0.006* Male 61 56.5 53 49.1 Age group 7–9 years 33 30.6 59 54.6 0.001* 10–11 years 28 25.9 31 28.7 12–13 years 47 43.5 18 16.7 MIH Absent 75 69.4 99 91.7 0.001* Present 33 30.6 9 8.3 HSPM Absent 106 98.1 101 93.5 0.170 Present 2 1.9 7 6.5 3.4 Severity of MIH The severity of MIH lesions differed significantly between the groups (χ² = 25.09, p < 0.001). In neurotypical children with MIH, the most common presentation was white/creamy demarcated opacities (88.9%, n = 8), followed by post-eruptive breakdown (11.1%, n = 1), atypical restorations (11.1%, n = 1), and atypical caries (22.2%, n = 2). None of the teeth were missing due to MIH in this group. In contrast, CSHCN demonstrated a higher prevalence of severe forms, with 31.6% (n = 12) showing white/creamy demarcated opacities, 15.8% (n = 6) presenting with post-eruptive breakdown, 42.1% (n = 16) with atypical caries, and 5.3% (n = 2) with missing teeth due to MIH. 3.5 Severity of HSPM The severity of HSPM also showed significant variation between groups (χ² = 4.56, p = 0.012). In neurotypical children with HSPM, 71.4% (n = 5) presented with white/creamy demarcated opacities, 14.3% (n = 1) had atypical restorations, and 14.3% (n = 1) had atypical caries. In contrast, all cases of HSPM in CSHCN (n = 2) presented with white/creamy demarcated opacities, and no cases with atypical restoration or atypical caries were observed (Fig. 7). 3.6 Lesion Extension of MIH The distribution of lesion extension in MIH-affected teeth differed significantly between groups (χ² = 6.06, p = 0.03). In neurotypical children, 50% (n = 6) of lesions were classified as extension I, 33.3% (n = 4) as extension II, and 16.7% (n = 2) as extension III. In CSHCN, 31.4% (n = 11) of lesions were extension I, 25.7% (n = 9) were extension II, and 42.9% (n = 15) were extension III, indicating a greater proportion of extensive lesions in this group (Fig. 8). 3.7 Lesion Extension of HSPM Lesion extension of HSPM did not differ significantly between groups (χ² = 2.45, p = 0.12). In neurotypical children, 75% (n = 3) of lesions were classified as extension I and 25% (n = 1) as extension II. In CSHCN, 50% (n = 1) of lesions were classified as extension I and 50% (n = 1) as extension II. 3.8 Distribution of MIH The distribution of affected teeth varied significantly between the two groups (χ² = 6.95, p = 0.031). In neurotypical children with MIH, 22.2% (n = 2) had only incisors affected, 44.4% (n = 4) had only molars affected, and 33.3% (n = 3) had both molars and incisors affected. In contrast, among CSHCN, the majority (84.8%, n = 28) presented with only molar involvement, 9.1% (n = 3) with only incisors, and 6.1% (n = 2) with both molars and incisors affected (Fig. 9). 4. DISCUSSION This study is the first to systematically compare the prevalence, severity, and distribution of MIH and HSPM between neurotypical children and children with special healthcare needs (CSHCN). In our group of 216 children aged 7 to 13 years, we found an overall MIH prevalence of 19.4% and an HSPM prevalence of 4.2%. The MIH prevalence was significantly higher in CSHCN (30.6%) compared to neurotypical peers (8.3%), which is consistent with the findings reported by Shetty AJ et al (Shetty et al. 2022 ). This finding highlights the increased vulnerability of children with special needs to enamel hypomineralisation. These results were in concordance with the study by Mohamed RN et al. who reported an overall MIH prevalence of 24.5% in CSHCN in Saudi Arabia (Mohamed et al. 2021 ). This link suggests that common health issues or exposures in CSHCN populations may worsen enamel disturbances. Conversely, the 8.3% MIH prevalence in neurotypical children falls within the lower range of what Indian studies have reported, typically ranging from 8% to 12% (Chowdhury et al. 2024 ; Rachmawati et al. 2025 ). In our study, a significantly higher prevalence of MIH was observed in children with intellectual disability, confirming the results obtained by Rajic VB et al., who reported 11.1% prevalence of MIH in children with intellectual disabilities (Brzovic Rajic et al. 2021 ). Similar trends were also observed in a study by Martinez et al. where 37% of children with intellectually disabled children had some developmental defect of enamel (Martinez et al. 2002; Erika et al. 2016 ). MIH is a multifactorial disorder arising due to systemic or environmental factors during the early maturation or late secretory phase of amelogenesis (Juárez-López et al. 2023 ; Fonseca-Souza et al. 2021 ). Health problems and illnesses during the prenatal, perinatal or postnatal periods and antibiotic use during the first four years of life are the potential etiologic factors that can result in MIH (Juárez-López et al. 2023 ; Thankappan et al. 2024 ). The increased MIH prevalence in CSHCN indicates that factors more common in this group may be involved. MIH is known to have multiple origins, with genetic and environmental factors influencing different levels of susceptibility. Early childhood illnesses, like fever, asthma, pneumonia, and systemic infections, have consistently been linked to MIH risk. CSHCN often experience more of these health issues, along with more frequent medication use, nutritional challenges, and physiological stress, which might disrupt the function of ameloblasts during enamel maturation (Sierant and Bartlett 2012 ). This was in agreement with Shan S et al., who reported an increased prevalence of developmental disturbances of enamel in children with autism spectrum disorder and attention-deficit hyperactivity disorder, suggesting that neurodevelopmental and systemic disturbances may adversely impact amelogenesis (Shan et al. 2025 ). In addition to prevalence, the findings on severity and lesion distribution reveal significant disparities. In the neurotypical group, MIH lesions were mostly mild (white or creamy opacities), with little breakdown or tooth loss. In contrast, CSHCN showed positive MIH cases with more severity, including yellow-brown demarcated opacities, post-eruptive breakdown, atypical caries, and extractions due to MIH. The presence of yellow-brown enamel opacities is more susceptible for post-eruptive breakdown which justifies the prevalence of lesions with greater severity in CSHCN group (Da Costa-Silva et al. 2011 ; Neves et al. 2019 ). The study did not find a significant difference in HSPM prevalence between CSHCN and neurotypical children. However, severity patterns varied: neurotypical children displayed different lesion types (opacities, atypical restorations, caries), while the few cases of HSPM in CSHCN presented uniformly as opacities. The small number of HSPM cases limits strong conclusions, but the trend does not support HSPM as a reliable early indicator for MIH in this group. Although the prevalence of HSPM was not as comparable to MIH, its overall prevalence of 6.5% remains noteworthy, as conditions affecting more than 5% of a population are considered epidemiologically significant (Berenstein et al. 2023). The literature on the aetiology of HSPM is unclear. The simultaneous growth phases of second primary molars and first permanent molars may be the etiological origin for presenting with similar abnormalities, although distinct susceptibilities among tooth types may also contribute to this phenomenon (Garot et al. 2018 ). Regular maintenance of oral hygiene remains as a challenge for the CSHCN group, due to their neurological or motor impairments. The recommendations for the management of MIH and HSPM should emphasize on early diagnosis of the lesions, educating the parents or caregivers about the condition and future consequences and facilitating treatment interventions at an early stage. Preventive care should be initiated, focusing on application of fluoride varnishes which promotes remineralization of the affected enamel, and use of casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) based products, which forms a protective layer rich in calcium and phosphate ions (Bakkal et al. 2017 ; Inchingolo et al. 2023 ). Centres for children with special healthcare needs should regularly promote the conductance of oral hygiene awareness programs. As MIH is a major risk for caries, regular use of oral health services, oral hygiene education and appropriate dietary counselling should be employed. An important strength of this study lies in its comparative design, evaluating both neurotypical children and those with special healthcare needs at the same point of time. This is the first Indian study to assess and compare the prevalence of MIH and HSPM in CSHCN. The relevance of these findings is significant, and it aids in early diagnosis and preventive care. The observed findings are consistent with the existing literature which highlights the impact of systemic conditions on the development of teeth. The study’s limitation is that the probable aetiological factors of MIH and HSPM could not be assessed as the children were enrolled in the schools on a timely basis and parents were unavailable during that time to gather information. Another limitation is the study design which is cross-sectional and the small sample size. Future longitudinal studies are required to substantiate the results obtained by monitoring enamel mineralisation over time in CSHCN and neurotypical groups to establish a causal relationship, which involves assessing the prenatal and perinatal factors and early childhood exposures. In addition, evaluating the genetic or epigenetic susceptibility in CSHCN may explain the occurrence of MIH. Future studies with a larger sample size, and longitudinal studies are necessary to substantiate the observed results from this study. Studies in other geographical areas should be conducted to investigate the prevalence among different populations, including children with special needs. 5. CONCLUSION This study revealed that children with special healthcare needs present with MIH more frequently and with greater severity than their neurotypical counterparts. However, hypomineralised second primary molars were fairly uncommon in both groups. In children with special healthcare needs, MIH lesions were not only more frequent but also larger and more severe. They showed signs of post-eruptive breakdown, caries, followed by tooth loss, which emphasises their increased vulnerability. These results highlight the need for timely detection, the necessity of preventive measures, and appropriate management strategies for children with special healthcare needs. 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J Dent. 2018;72:8–13. https://doi.org/10.1016/j.jdent.2018.03.005 Bakkal M., Abbasoglu Z., Kargul B. The Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate on Molar-Incisor Hypomineralisation: A Pilot Study. Oral Health Prev. Dent. 2017;15:163–167. https://doi.org/10.3290/j.ohpd.a37928 . Inchingolo AM, Inchingolo AD, Viapiano F, Ciocia AM, Ferrara I, Netti A, Dipalma G, Palermo A, Inchingolo F. Treatment Approaches to Molar Incisor Hypomineralization: A Systematic Review. J Clin Med. 2023;12(22):7194. https://doi.org/10.3390/jcm12227194 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 31 Jan, 2026 Reviews received at journal 30 Jan, 2026 Reviewers agreed at journal 30 Jan, 2026 Reviews received at journal 22 Jan, 2026 Reviewers agreed at journal 21 Jan, 2026 Reviewers invited by journal 21 Jan, 2026 Editor assigned by journal 15 Dec, 2025 Submission checks completed at journal 15 Dec, 2025 First submitted to journal 12 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8347247","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":578829314,"identity":"90a6cb88-a06b-4702-9606-beae6f642e88","order_by":0,"name":"Ishwarya Shanmugam","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Ishwarya","middleName":"","lastName":"Shanmugam","suffix":""},{"id":578829315,"identity":"f9cdc726-5696-485a-a508-08c7702ea20a","order_by":1,"name":"Arulpari 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09:43:22","extension":"xml","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":88619,"visible":true,"origin":"","legend":"","description":"","filename":"2ca51dc7eeae4cc2a88715d921c51a471structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/fef8d4c572d05028d3dd99ae.xml"},{"id":101019549,"identity":"f7a415bd-2ba6-4f55-b819-ea5315ab52ef","added_by":"auto","created_at":"2026-01-24 00:39:05","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":98592,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/bf7a9ef85587f3ac84bc04d9.html"},{"id":101204104,"identity":"659efdd4-054a-4cde-9142-6baee2f5e066","added_by":"auto","created_at":"2026-01-27 09:41:36","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":45576,"visible":true,"origin":"","legend":"\u003cp\u003eFormula used for sample size calculation\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/9eb87606fbdb3a99c035749c.png"},{"id":101019560,"identity":"bce0c7a9-a714-4633-95b3-89ea47abbead","added_by":"auto","created_at":"2026-01-24 00:39:07","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1426630,"visible":true,"origin":"","legend":"\u003cp\u003eStandardized intraoral photographs of MIH-affected teeth taken during clinical examination under ambient or operatory lighting. \u003cstrong\u003eA \u003c/strong\u003eWhite, creamy opacity affecting the maxillary incisor; \u003cstrong\u003eB, C \u003c/strong\u003eYellow-brown, demarcated opacities affecting the maxillary molars; \u003cstrong\u003eD, E \u003c/strong\u003ePost-eruptive enamel breakdown with dentin exposure in molars\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/151ab85e1ca6f2745ff7937a.png"},{"id":101019537,"identity":"d6107ecd-1988-47ca-9750-094d005bb9d6","added_by":"auto","created_at":"2026-01-24 00:39:04","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":732939,"visible":true,"origin":"","legend":"\u003cp\u003eStandardized intraoral photographs of HSPM taken during clinical examination under ambient or operatory lighting. \u003cstrong\u003eA \u003c/strong\u003eYellow-brown, demarcated opacities; \u003cstrong\u003eB \u003c/strong\u003eAtypical caries; \u003cstrong\u003eC \u003c/strong\u003eAtypical restoration\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/6fe578d503170fe98dd0250d.png"},{"id":101019542,"identity":"ff030983-2df1-4ab4-a418-a8b6900ea068","added_by":"auto","created_at":"2026-01-24 00:39:04","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":175781,"visible":true,"origin":"","legend":"\u003cp\u003eProportion of children in each diagnostic category within the special healthcare needs (CSHCN) group, illustrating the relative frequency of attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), intellectual disability (ID), global developmental delay (GDD), cerebral palsy (CP), Down syndrome, mental retardation (MR), and multiple disabilities.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/2b850fa436adb3b183962f4d.png"},{"id":101019555,"identity":"459a6bd8-f3ea-4d55-a097-07664c5d7097","added_by":"auto","created_at":"2026-01-24 00:39:05","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":43470,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of age-group distribution between neurotypical children and CSHCN.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/9c4b1abd2ee3b08d64f39a4f.png"},{"id":101204442,"identity":"44853183-6524-48d1-8f21-5af41742d4c9","added_by":"auto","created_at":"2026-01-27 09:43:07","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":71678,"visible":true,"origin":"","legend":"\u003cp\u003eBar chart depicting the number of children with and without MIH in the two study groups; \u003cstrong\u003eB \u003c/strong\u003eBar chart depicting the number of children with and without HSPM in the two study groups.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/4e2dccd255d0d9cb9c456be7.png"},{"id":101019538,"identity":"c4bdde63-4050-4a5d-93ee-cb3979f3a26e","added_by":"auto","created_at":"2026-01-24 00:39:04","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":107542,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the severity of molar–incisor hypomineralisation (MIH) between CSHCN and neurotypical children\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/1d10233b789814465b8fee65.png"},{"id":101019539,"identity":"e046b0d6-1be7-4649-9f3f-aa756ec774e0","added_by":"auto","created_at":"2026-01-24 00:39:04","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":105825,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the lesion extension of molar–incisor hypomineralisation (MIH) between CSHCN and neurotypical children\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/e7cba3cb9da1042a0b805497.png"},{"id":101019540,"identity":"e35d6d54-19de-42b0-b92c-412598424340","added_by":"auto","created_at":"2026-01-24 00:39:04","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":67612,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the distribution pattern of molar–incisor hypomineralisation (MIH) between CSHCN and neurotypical children\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/6d7b143e808a9cc9a86286ed.png"},{"id":101398926,"identity":"171232ba-d407-4b25-98eb-3ef7752d4d3b","added_by":"auto","created_at":"2026-01-29 09:50:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6132426,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8347247/v1/8c3e3e61-32c0-4d7e-b8ab-b3f33ff98300.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Prevalence and Clinical Patterns of Molar-Incisor Hypomineralisation and Hypomineralised Second Primary Molars among Children with Special Healthcare Needs: A Comparative Cross-Sectional Study","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eTooth formation can be impacted by a variety of genetic and environmental factors both during and after birth (Alaluusua \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Enamel is a type of tissue that does not have the ability to remineralize, making it susceptible to structural changes resulting from systemic disturbances in the amelogenesis process (Emmatty et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The term molar incisor hypomineralisation (MIH) refers to hypomineralisation of systemic origin that manifests as distinct, qualitative defects of the enamel of one to four first permanent molars (FPMs) and are often associated with incisors (Weerheijm K et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). The severity ranges from mild, demarcated opacities to post-eruptive enamel breakdown (PEB) which can lead to problems in aesthetics and hypersensitivity adversely affecting the quality of life (Silva et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The presence of hypomineralised second primary molars (HSPM) serves as an indicator for Molar-Incisor Hypomineralisation (MIH), with a greater prevalence of MIH correlated to the presence of mild HSPM. These conditions exhibit a similar clinical presentation to MIH, mostly due to overlapping periods of amelogenesis (Singh et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMolar-incisor hypomineralisation is widely prevalent, with rates ranging from 2.4% to 40.2% (J\u0026auml;levik \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). In India, the estimated prevalence of MIH is around 10.0% (Shetty et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The observed wide range in prevalence rates can be attributed to variations in indices and age demographics (Yannam 2016). The limited awareness regarding MIH and HSPM may lead to various clinical findings that remain unnoticed, resulting in biased diagnoses and potentially affecting treatment options. Compared to their counterparts without the condition, children with MIH are at an increased risk of dental caries.\u003c/p\u003e \u003cp\u003eChildren with special health care needs (CSHCN) present with physical, developmental, mental, sensory, behavioural, cognitive, or emotional impairment or limiting condition requiring medical management. This condition can be congenital, developmental, or acquired through disease, trauma, or environmental factors, and it restricts their ability to carry out daily activities (American Academy of Pediatric Dentistry \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Prior research has indicated variable prevalence of enamel developmental defects in children with special health care needs (Aarthy and Kumar \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Lin et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The children under this category may frequently present with medical complications peri and postnatally, which can elevate the risk of hypoxia. These hypoxic conditions can invariably affect the process of amelogenesis leading to such enamel defects. Evidence regarding the prevalence of developmental defects of enamel in children with special healthcare needs has been documented. However, there have been sparse studies assessing the prevalence of MIH and HSPM in such groups. Hence, the purpose of this comparative, cross-sectional study is to evaluate the prevalence of MIH and HSPM and to assess whether children with special health care needs (CSHCN) have a higher risk of MIH and HSPM than neurotypical children aged 7\u0026ndash;13 years, by estimating and comparing prevalence, severity, distribution, and age-specific patterns.\u003c/p\u003e"},{"header":"2. METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Study Design and Setting\u003c/h2\u003e\n \u003cp\u003eThis cross-sectional study was performed on children aged 7 to 13 years. The study population was divided into two groups: children with special healthcare needs (CSHCN) and neurotypical children as the control group. A total of 216 children were examined, comprising 108 neurotypical children as control group and 108 children with special healthcare needs. The neurotypical children who reported to the outpatient department of the Department of Pediatric and Preventive Dentistry at Sri Ramachandra Dental College and Hospital, Chennai and Department of Paediatrics, Sri Ramachandra Hospital were examined, whereas the CSHCN group was selected from several special schools in Chennai. The study was conducted from April to June 2025. Ethical clearance was obtained from the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education and Research (CSP-III/25/FEB/17/103). Written informed consent was obtained from the parents or guardians of all participants wherever possible, and written assent was obtained from neurotypical children before clinical examination. Prior consent was obtained from the schools for children with special healthcare needs for conducting the study.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Inclusion and Exclusion Criteria\u003c/h2\u003e\n \u003cp\u003eThe study included children aged 7 to 13 years who had at least one erupted first permanent molar for diagnosis of MIH and second primary molars for HSPM. Children exhibiting generalized developmental enamel defects, including amelogenesis imperfecta or fluorosis, as well as those with syndromic conditions that affect the dentition, were excluded. Children who were uncooperative or whose parents did not give permission were also excluded.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Sample Size Calculation\u003c/h2\u003e\n \u003cp\u003eSample size was calculated using the formula as shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/p\u003e\n \u003cp\u003eWhere,\u003c/p\u003e\n \u003cp\u003e͞p\u0026thinsp;=\u0026thinsp;P\u003csub\u003e1 +\u003c/sub\u003e P\u003csub\u003e2\u003c/sub\u003e / 2\u003c/p\u003e\n \u003cp\u003eP\u003csub\u003e1\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;Proportion in first group\u003c/p\u003e\n \u003cp\u003eP\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;Proportion in first group\u003c/p\u003e\n \u003cp\u003e\u0026alpha;\u0026thinsp;=\u0026thinsp;Significance level\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003e1-\u0026beta;\u0026thinsp;=\u0026thinsp;Power of the study\u003c/h3\u003e\n\u003cp\u003eG*Power software version 3.1 was used for a chi-square test comparing the proportions between CSHCN and neurotypical children groups. The power of the study was set at 80% and an effect size of 0.28 to derive a minimum size of 78 per group. The final sample size of 216 (108 neurotypical and 108 CSHCN) was finalized after considering the potential exclusions due to ineligibility or non-cooperation.\u003c/p\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Clinical Examination\u003c/h2\u003e\n \u003cp\u003eAll examinations were carried out by a single trained and calibrated examiner under natural daylight using sterile mouth mirrors and straight probes, with additional illumination provided when necessary. The diagnostic criteria recommended by the European Academy of Paediatric Dentistry (EAPD), 2003 were employed to identify MIH and HSPM based on the criteria described by Ghanim et al. (Lygidakis et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). Children were considered to be affected by MIH if one or more PFMs were involved with or without permanent incisor involvement. The clinical\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e2.5 Examiner Calibration\u003c/h2\u003e\n \u003cp\u003eThe examiner underwent calibration before the study under the supervision of an experienced pediatric dentist. Intra-examiner reliability was assessed by re-examining 20 children at an interval of two weeks, and the results were compared using Cohen\u0026rsquo;s kappa statistic. A kappa value of 0.82 was obtained, indicating almost perfect agreement and confirming the reliability of the examiner in diagnosing MIH and HSPM. Data were recorded in a structured proforma noting the presence, severity and lesion extension of MIH and HSPM.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003e2.6 Statistical Analysis\u003c/h2\u003e\n \u003cp\u003eThe collected data were entered into Microsoft Excel and descriptive and inferential statistics were analysed using IBM Statistical Package for the Social Sciences (SPSS) software version 30.0 (IBM Corp. Released 2024. IBM SPSS Statistics for Windows, Version 30.0. Armonk, NY: IBM Corp). Frequency and Percentage were used to summarize the qualitative data. Chi-square test was used for comparison of prevalence data between Neurotypical and CSHCN. A p value of \u0026le;\u0026thinsp;0.05 was considered as statistically significant difference.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. RESULTS","content":"\u003cp\u003eA total of 216 children, comprising 108 neurotypical children and 108 children with special healthcare needs (CSHCN), aged 7 to 13 years, 114 males and 102 females, were included in the study. After collecting the records from school, we investigated children with behavioural disorders such as autism spectrum disorder and attention-deficit hyperactivity disorder, cognitive disorders such as intellectual disability, developmental disorders like cerebral palsy, and congenital disorders such as Down syndrome. Among the 107 CSHCN, 30 (27.8%) presented with intellectual disability (ID), 20 (18.5%) with autism spectrum disorder (ASD), 19 (17.6%) with ADHD. Less commonly prevalent conditions were global developmental delay (6.5%, n = 7), cerebral palsy (5.6%, n = 6), mental retardation (0.9%, n = 1) and 17 children presented with multiple disabilities (n = 15.7%).\u003c/p\u003e\n\u003cdiv id=\"Sec11\"\u003e\n \u003ch2\u003e3.1 Age Group Distribution\u003c/h2\u003e\n \u003cp\u003eIn the neurotypical group, the majority of children (54.6%, n = 59) were between 7–9 years of age, while 28.7% (n = 31) were 10–11 years and 16.7% (n = 18) were 12–13 years. In contrast, CSHCN were more evenly distributed, with 30.6% (n = 33) in the 7–9-year group, 25.9% (n = 28) in the 10–11-year group, and a higher proportion (43.5%, n = 47) in the 12–13-year group. The difference in age distribution between the two groups was statistically significant (χ² = 20.43, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001) as given in Table\u0026nbsp;2. The graph is shown in Fig.\u0026nbsp;5.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\"\u003e\n \u003ch2\u003e3.2 Gender distribution\u003c/h2\u003e\n \u003cp\u003eThe CSHCN group had a higher proportion of males (56.5%; n = 61) than females (43.5%; n = 47). In the neurotypical group, females constituted 50.9% (n = 55) of the sample, while males accounted for 49.1% (n = 53). The gender difference between the two groups was statistically significant (χ² = 7.45, \u003cem\u003ep\u003c/em\u003e = 0.006), indicating that males were disproportionately represented among the two groups (Table\u0026nbsp;2).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\"\u003e\n \u003ch2\u003e3.3 Prevalence of MIH and HSPM\u003c/h2\u003e\n \u003cp\u003eThe overall prevalence of MIH was 19.4%. Among neurotypical children, the prevalence of MIH was 8.3% (n = 9), while in CSHCN it was significantly higher at 30.6% (n = 33). The difference was statistically significant (χ² = 17.025, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). The prevalence of HSPM was 6.5% (n = 7) in neurotypical children and 1.9% (n = 2) in CSHCN. This difference was not statistically significant (χ² = 2.89, \u003cem\u003ep\u003c/em\u003e = 0.170). Figure\u0026nbsp;6A and 6B shows the prevalence of MIH and HSPM. Table\u0026nbsp;1 shows the frequency of MIH in different conditions.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 1\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eDescriptive data of frequency of MIH in different conditions among CSHCN\u0026nbsp;\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eType of disability\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMIH Present\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIntellectual disability (n = 30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7 (6.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAutism spectrum disorder (n = 20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6 (5.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAttention-deficit hyperactivity disorder (n = 19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3 (2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGlobal developmental delay (n = 7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4 (3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCerebral palsy (n = 6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1 (0.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDown syndrome (n = 8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6 (5.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMultiple disabilities (n = 17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6 (5.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003ePrevalence of HSPM was rare within the CSHCN population. Only two children (1.8%, n = 2) presented with HSPM, which was observed in children with cerebral palsy.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 2\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eDistribution of gender, age groups, and prevalence of MIH and HSPM among children with special healthcare needs (CSHCN) and neurotypical controls\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"7\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCSHCN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eControls\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGender\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.006*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e49.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7–9 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10–11 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12–13 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMIH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbsent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e91.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePresent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHSPM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbsent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e106\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e98.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e101\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e93.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.170\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePresent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\"\u003e\n \u003ch2\u003e3.4 Severity of MIH\u003c/h2\u003e\n \u003cp\u003eThe severity of MIH lesions differed significantly between the groups (χ² = 25.09, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). In neurotypical children with MIH, the most common presentation was white/creamy demarcated opacities (88.9%, n = 8), followed by post-eruptive breakdown (11.1%, n = 1), atypical restorations (11.1%, n = 1), and atypical caries (22.2%, n = 2). None of the teeth were missing due to MIH in this group. In contrast, CSHCN demonstrated a higher prevalence of severe forms, with 31.6% (n = 12) showing white/creamy demarcated opacities, 15.8% (n = 6) presenting with post-eruptive breakdown, 42.1% (n = 16) with atypical caries, and 5.3% (n = 2) with missing teeth due to MIH.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\"\u003e\n \u003ch2\u003e3.5 Severity of HSPM\u003c/h2\u003e\n \u003cp\u003eThe severity of HSPM also showed significant variation between groups (χ² = 4.56, \u003cem\u003ep\u003c/em\u003e = 0.012). In neurotypical children with HSPM, 71.4% (n = 5) presented with white/creamy demarcated opacities, 14.3% (n = 1) had atypical restorations, and 14.3% (n = 1) had atypical caries. In contrast, all cases of HSPM in CSHCN (n = 2) presented with white/creamy demarcated opacities, and no cases with atypical restoration or atypical caries were observed (Fig.\u0026nbsp;7).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\"\u003e\n \u003ch2\u003e3.6 Lesion Extension of MIH\u003c/h2\u003e\n \u003cp\u003eThe distribution of lesion extension in MIH-affected teeth differed significantly between groups (χ² = 6.06, \u003cem\u003ep\u003c/em\u003e = 0.03). In neurotypical children, 50% (n = 6) of lesions were classified as extension I, 33.3% (n = 4) as extension II, and 16.7% (n = 2) as extension III. In CSHCN, 31.4% (n = 11) of lesions were extension I, 25.7% (n = 9) were extension II, and 42.9% (n = 15) were extension III, indicating a greater proportion of extensive lesions in this group (Fig.\u0026nbsp;8).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec17\"\u003e\n \u003ch2\u003e3.7 Lesion Extension of HSPM\u003c/h2\u003e\n \u003cp\u003eLesion extension of HSPM did not differ significantly between groups (χ² = 2.45, \u003cem\u003ep\u003c/em\u003e = 0.12). In neurotypical children, 75% (n = 3) of lesions were classified as extension I and 25% (n = 1) as extension II. In CSHCN, 50% (n = 1) of lesions were classified as extension I and 50% (n = 1) as extension II.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec18\"\u003e\n \u003ch2\u003e3.8 Distribution of MIH\u003c/h2\u003e\n \u003cp\u003eThe distribution of affected teeth varied significantly between the two groups (χ² = 6.95, \u003cem\u003ep\u003c/em\u003e = 0.031). In neurotypical children with MIH, 22.2% (n = 2) had only incisors affected, 44.4% (n = 4) had only molars affected, and 33.3% (n = 3) had both molars and incisors affected. In contrast, among CSHCN, the majority (84.8%, n = 28) presented with only molar involvement, 9.1% (n = 3) with only incisors, and 6.1% (n = 2) with both molars and incisors affected (Fig.\u0026nbsp;9).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. DISCUSSION","content":"\u003cp\u003eThis study is the first to systematically compare the prevalence, severity, and distribution of MIH and HSPM between neurotypical children and children with special healthcare needs (CSHCN). In our group of 216 children aged 7 to 13 years, we found an overall MIH prevalence of 19.4% and an HSPM prevalence of 4.2%. The MIH prevalence was significantly higher in CSHCN (30.6%) compared to neurotypical peers (8.3%), which is consistent with the findings reported by Shetty AJ et al (Shetty et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This finding highlights the increased vulnerability of children with special needs to enamel hypomineralisation.\u003c/p\u003e \u003cp\u003eThese results were in concordance with the study by Mohamed RN et al. who reported an overall MIH prevalence of 24.5% in CSHCN in Saudi Arabia (Mohamed et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). This link suggests that common health issues or exposures in CSHCN populations may worsen enamel disturbances. Conversely, the 8.3% MIH prevalence in neurotypical children falls within the lower range of what Indian studies have reported, typically ranging from 8% to 12% (Chowdhury et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Rachmawati et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn our study, a significantly higher prevalence of MIH was observed in children with intellectual disability, confirming the results obtained by Rajic VB et al., who reported 11.1% prevalence of MIH in children with intellectual disabilities (Brzovic Rajic et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Similar trends were also observed in a study by Martinez et al. where 37% of children with intellectually disabled children had some developmental defect of enamel (Martinez et al. 2002; Erika et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMIH is a multifactorial disorder arising due to systemic or environmental factors during the early maturation or late secretory phase of amelogenesis (Ju\u0026aacute;rez-L\u0026oacute;pez et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Fonseca-Souza et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Health problems and illnesses during the prenatal, perinatal or postnatal periods and antibiotic use during the first four years of life are the potential etiologic factors that can result in MIH (Ju\u0026aacute;rez-L\u0026oacute;pez et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Thankappan et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). The increased MIH prevalence in CSHCN indicates that factors more common in this group may be involved. MIH is known to have multiple origins, with genetic and environmental factors influencing different levels of susceptibility. Early childhood illnesses, like fever, asthma, pneumonia, and systemic infections, have consistently been linked to MIH risk. CSHCN often experience more of these health issues, along with more frequent medication use, nutritional challenges, and physiological stress, which might disrupt the function of ameloblasts during enamel maturation (Sierant and Bartlett \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). This was in agreement with Shan S et al., who reported an increased prevalence of developmental disturbances of enamel in children with autism spectrum disorder and attention-deficit hyperactivity disorder, suggesting that neurodevelopmental and systemic disturbances may adversely impact amelogenesis (Shan et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn addition to prevalence, the findings on severity and lesion distribution reveal significant disparities. In the neurotypical group, MIH lesions were mostly mild (white or creamy opacities), with little breakdown or tooth loss. In contrast, CSHCN showed positive MIH cases with more severity, including yellow-brown demarcated opacities, post-eruptive breakdown, atypical caries, and extractions due to MIH. The presence of yellow-brown enamel opacities is more susceptible for post-eruptive breakdown which justifies the prevalence of lesions with greater severity in CSHCN group (Da Costa-Silva et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Neves et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe study did not find a significant difference in HSPM prevalence between CSHCN and neurotypical children. However, severity patterns varied: neurotypical children displayed different lesion types (opacities, atypical restorations, caries), while the few cases of HSPM in CSHCN presented uniformly as opacities. The small number of HSPM cases limits strong conclusions, but the trend does not support HSPM as a reliable early indicator for MIH in this group. Although the prevalence of HSPM was not as comparable to MIH, its overall prevalence of 6.5% remains noteworthy, as conditions affecting more than 5% of a population are considered epidemiologically significant (Berenstein et al. 2023).\u003c/p\u003e \u003cp\u003eThe literature on the aetiology of HSPM is unclear. The simultaneous growth phases of second primary molars and first permanent molars may be the etiological origin for presenting with similar abnormalities, although distinct susceptibilities among tooth types may also contribute to this phenomenon (Garot et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e Regular maintenance of oral hygiene remains as a challenge for the CSHCN group, due to their neurological or motor impairments. The recommendations for the management of MIH and HSPM should emphasize on early diagnosis of the lesions, educating the parents or caregivers about the condition and future consequences and facilitating treatment interventions at an early stage. Preventive care should be initiated, focusing on application of fluoride varnishes which promotes remineralization of the affected enamel, and use of casein phosphopeptide\u0026ndash;amorphous calcium phosphate (CPP-ACP) based products, which forms a protective layer rich in calcium and phosphate ions (Bakkal et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Inchingolo et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Centres for children with special healthcare needs should regularly promote the conductance of oral hygiene awareness programs. As MIH is a major risk for caries, regular use of oral health services, oral hygiene education and appropriate dietary counselling should be employed.\u003c/p\u003e \u003cp\u003eAn important strength of this study lies in its comparative design, evaluating both neurotypical children and those with special healthcare needs at the same point of time. This is the first Indian study to assess and compare the prevalence of MIH and HSPM in CSHCN. The relevance of these findings is significant, and it aids in early diagnosis and preventive care. The observed findings are consistent with the existing literature which highlights the impact of systemic conditions on the development of teeth. The study\u0026rsquo;s limitation is that the probable aetiological factors of MIH and HSPM could not be assessed as the children were enrolled in the schools on a timely basis and parents were unavailable during that time to gather information. Another limitation is the study design which is cross-sectional and the small sample size. Future longitudinal studies are required to substantiate the results obtained by monitoring enamel mineralisation over time in CSHCN and neurotypical groups to establish a causal relationship, which involves assessing the prenatal and perinatal factors and early childhood exposures. In addition, evaluating the genetic or epigenetic susceptibility in CSHCN may explain the occurrence of MIH. Future studies with a larger sample size, and longitudinal studies are necessary to substantiate the observed results from this study. Studies in other geographical areas should be conducted to investigate the prevalence among different populations, including children with special needs.\u003c/p\u003e"},{"header":"5. CONCLUSION","content":"\u003cp\u003eThis study revealed that children with special healthcare needs present with MIH more frequently and with greater severity than their neurotypical counterparts.\u003c/p\u003e \u003cp\u003eHowever, hypomineralised second primary molars were fairly uncommon in both groups. In children with special healthcare needs, MIH lesions were not only more frequent but also larger and more severe. They showed signs of post-eruptive breakdown, caries, followed by tooth loss, which emphasises their increased vulnerability. These results highlight the need for timely detection, the necessity of preventive measures, and appropriate management strategies for children with special healthcare needs. Future studies should evaluate the possible etiologic factors in a longitudinal basis in such populations to better understand the aetiology and improve prevention and treatment modalities.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eIS: conceptualization, methodology, data curation, formal analysis and investigation, writing and funding acquisition; AP: conceptualization, writing - review and editing, supervision; SH: writing - review and editing, resources, supervision; PJ: methodology, supervision; SSS: data curation, formal analysis and investigation; SLS: formal analysis and investigation\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlaluusua S. Aetiology of molar-incisor hypomineralisation: a systematic review. 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J Dent. 2018;72:8\u0026ndash;13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jdent.2018.03.005\u003c/span\u003e\u003cspan address=\"10.1016/j.jdent.2018.03.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBakkal M., Abbasoglu Z., Kargul B. The Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate on Molar-Incisor Hypomineralisation: A Pilot Study. Oral Health Prev. Dent. 2017;15:163\u0026ndash;167. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3290/j.ohpd.a37928\u003c/span\u003e\u003cspan address=\"10.3290/j.ohpd.a37928\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInchingolo AM, Inchingolo AD, Viapiano F, Ciocia AM, Ferrara I, Netti A, Dipalma G, Palermo A, Inchingolo F. Treatment Approaches to Molar Incisor Hypomineralization: A Systematic Review. J Clin Med. 2023;12(22):7194. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/jcm12227194\u003c/span\u003e\u003cspan address=\"10.3390/jcm12227194\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-archives-of-paediatric-dentistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"EAPD","sideBox":"Learn more about [European Archives of Paediatric Dentistry](https://link.springer.com/journal/40368)","snPcode":"40368","submissionUrl":"https://submission.springernature.com/new-submission/40368/3","title":"European Archives of Paediatric Dentistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"children with special healthcare needs, developmental enamel defects, good health and well-being, hypomineralised second primary molars, molar-incisor hypomineralisation, neurodevelopmental disorders, pediatric dentistry","lastPublishedDoi":"10.21203/rs.3.rs-8347247/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8347247/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose:\u003c/h2\u003e \u003cp\u003eDevelopmental enamel defects, commonly seen in children, have proven to pose clinical challenges for pediatric dentists. Among these, Molar-Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) are among the most common enamel defects and each of these has important clinical implications. Children with special healthcare needs (CSHCN) may be more likely to have developmental enamel defects due to systemic, perinatal \u0026amp; environmental factors. The aim of this study was to assess and compare the prevalence, distribution and clinical patterns of molar-incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPM) in children with special healthcare needs and neurotypical children aged 7\u0026ndash;13 years.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e \u003cp\u003eA comparative cross-sectional study was conducted among 216 children (108 neurotypical children and 108 CSHCN) by a calibrated examiner following the EAPD Diagnostic criteria for MIH/HSPM. Prevalence, severity and lesion extension of MIH and HSPM were noted. Data was analysed using the Chi-square test (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 considered statistically significant).\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e \u003cp\u003eThe overall prevalence of MIH was 19.4%. MIH prevalence was greater in CSHCN (30.6%) than neurotypical children (8.3%). HSPM prevalence was 4.2% and showed no significance. Severity of MIH was greater within the CSHCN group with 42.1% having atypical caries and 15.8% showing post-eruptive breakdown due to MIH compared to neurotypical peers. Lesion extension was also greater in CSHCN. In CSHCN, most cases involved only molars (84.8%) while neurotypical children showed more molar-incisor involvement.\u003c/p\u003e\u003ch2\u003eConclusion:\u003c/h2\u003e \u003cp\u003eChildren with special healthcare needs have a significantly greater prevalence and severity of MIH. These findings emphasize the need to implicate early preventive strategies, proper parental awareness and timely intervention, thereby improving the overall well-being and quality of life in such individuals.\u003c/p\u003e","manuscriptTitle":"Prevalence and Clinical Patterns of Molar-Incisor Hypomineralisation and Hypomineralised Second Primary Molars among Children with Special Healthcare Needs: A Comparative Cross-Sectional Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-24 00:38:59","doi":"10.21203/rs.3.rs-8347247/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-31T06:06:20+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-30T06:44:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"47039686190907994078458103259089374498","date":"2026-01-30T05:20:32+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-22T07:31:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"261844721606748531361497897422951889731","date":"2026-01-22T00:48:55+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-21T18:12:53+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-15T05:21:49+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-15T05:21:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Archives of Paediatric Dentistry","date":"2025-12-12T15:32:13+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-archives-of-paediatric-dentistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"EAPD","sideBox":"Learn more about [European Archives of Paediatric Dentistry](https://link.springer.com/journal/40368)","snPcode":"40368","submissionUrl":"https://submission.springernature.com/new-submission/40368/3","title":"European Archives of Paediatric Dentistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"94961861-e752-4e9c-818a-35848f0c914f","owner":[],"postedDate":"January 24th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-21T20:08:16+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-24 00:38:59","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8347247","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8347247","identity":"rs-8347247","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}