**Molar Incisor Hypomineralisation (MIH) & Hypomineralised Second Primary Molars (HSPM)** **Dr Jilen Patel** *PhD, BDSc (Hons) WA, DClinDent, MRACDS, FADI, FICD, FPFA, SFHEA* Specialist Paediatric Dentist Senior Lecturer, UWA Dental School Consultant, Perth Children’s Hospital #### Presenter Profile **Dr Jilen Patel** *PhD, BDSc (Hons) WA, DClinDent, MRACDS, FADI, FICD, FPFA, SFHEA* - Specialist Paediatric Dentist - Senior Lecturer, UWA Dental School - Consultant, Perth Children’s Hospital # **Lecture Outcomes** - Define MIH and HSPM - Describe the prevalence of both conditions - Understand the clinical manifestations of both MIH and HSPM - Explain the aetiological concepts of MIH - Identify treatment options for teeth affected by MIH and HSPM  #### Lecture Outcomes By the end of this session, participants should be able to: - Define Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) - Describe the prevalence of both conditions - Understand the clinical manifestations of both MIH and HSPM - Explain the aetiological concepts of MIH - Identify treatment options for teeth affected by MIH and HSPM The University of Western Australia logo featuring a shield with a swan and books. Hypoplasia Enamel hypoplasia is a quantitative deficiency of developmental defects of enamel, which usually arise from disruptions of matrix formation It may be expressed as: - pits - grooves - thin enamel - missing enamel Clarkson & O'Mullane, 1989   Enamel hypoplasia is a quantitative deficiency of developmental defects of enamel, which usually arise from disruptions of matrix formation. #### Clinical Expression It may be expressed as: - Pits - Grooves - Thin enamel - Missing enamel (Clarkson & O'Mullane, 1989) Clinical photo showing anterior teeth with visible enamel hypoplasia on the upper central incisors, characterized by pitted and discolored areas consistent with 'pits' or 'grooves' mentioned in the text. Clinical photo showing posterior teeth with severe enamel hypoplasia, including thin enamel and missing enamel sections, illustrating the developmental defects described in the OCR text. Hypomineralisation - **Qualitative enamel defect** - Usually associated with altered enamel mineralisation - May be expressed as changes in the translucency or opacity of the enamel - May be diffuse or demarcated, and colored white, yellow, or brown **THE UNIVERSITY OF WESTERN AUSTRALIA**  #### Characteristics of Hypomineralisation - **Qualitative enamel defect**: Usually associated with altered enamel mineralisation. - **Visual Appearance**: May be expressed as changes in the translucency or opacity of the enamel. - **Presentation**: May be diffuse or demarcated, and colored white, yellow, or brown. Clinical photo of a patient's anterior dentition showing hypomineralisation. The image displays the upper and lower central incisors with visible enamel defects characterized by opacities and discoloration ranging from white to yellow/brown patches, consistent with the text description of qualitative enamel defects. **Hypoplasia / Hypomineralisation** THE UNIVERSITY OF WESTERN AUSTRALIA  Hypoplasia / Hypomineralisation Clinical intraoral photograph of anterior teeth demonstrating hypoplasia and hypomineralisation. The upper central incisors show enamel defects; the right upper central incisor exhibits a distinct yellow-brown discoloration with surface pitting and rough texture, characteristic of severe enamel hypomineralisation. - Hypomineralisation of systemic origin affecting one, two or three or all first permanent molars and the permanent incisors - Sometimes secondary primary molars and the tips of the permanent canines are also involved (Weerheijm et al. 2001 and 2003)  #### Definition and Scope - Hypomineralisation of systemic origin affecting one, two, three, or all first permanent molars and the permanent incisors. - Sometimes secondary primary molars and the tips of the permanent canines are also involved. (Weerheijm et al. 2001 and 2003) Clinical photo showing a close-up view of the upper right posterior teeth in an oral cavity. The image demonstrates severe Molar Incisor Hypomineralisation (MIH). The first permanent molar exhibits extensive, opaque yellow-brown discoloration with significant surface breakdown and structural loss, consistent with the text description of hypomineralisation affecting first permanent molars. Adjacent teeth show varying degrees of enamel opacity. **Molar Incisor Hypomineralisation** THE UNIVERSITY OF WESTERN AUSTRALIA      Molar Incisor Hypomineralisation Clinical photo showing a posterior view of molars with visible yellowish-brown discoloration on the occlusal surfaces, consistent with Molar Incisor Hypomineralisation. Clinical photo showing another posterior view of molars with similar hypomineralised lesions characterized by chalky white to yellow-brown opacities. Clinical photo showing a close-up of a molar with a distinct yellow-brown lesion on the occlusal surface; a dental instrument is visible in the lower right corner. Clinical photo showing an occlusal view of a molar with significant yellow-brown discoloration and rough texture indicative of hypomineralisation. Clinical photo showing anterior teeth (incisors/canines) with smooth enamel surfaces, likely included for comparison or as part of the case presentation. # **Prevalence** - The world wide prevalence varies from 2.4 - 40.2% (Jälevik, 2010) - Australia: 22 - 44 % (Arrow et al. 2008; Balmer et al. 2005) - New Zealand: 14.9 - 18.8% (Mahoney & Morrison, 2009, 2011) #### Global and Regional Prevalence - **Worldwide**: Prevalence varies from 2.4 - 40.2% (Jälevik, 2010). - **Australia**: 22 - 44% (Arrow et al. 2008; Balmer et al. 2005). - **New Zealand**: 14.9 - 18.8% (Mahoney & Morrison, 2009, 2011). **Prevalence** The University of Western Australia Int J Paediatr Dent. 2018 Mar;28(2):170-179. doi: 10.1111/ipd.12323. Epub 2017 Jul 21. **The prevalence of molar incisor hypomineralization: evidence from 70 studies** Dongdong Zhao <sup>1</sup>, Bao Dong <sup>1</sup>, Dandan Yu <sup>1</sup>, Qiongqiong Ren <sup>1</sup>, Yehuan Sun <sup>1</sup><sup>2</sup> Affiliations + expand PMID: 28732120, DOI: **10.1111/ipd.12323** **Abstract** **Objective:** A growing number of studies have investigated the prevalence of Molar Incisor Hypomineralization (MIH) around the world. The aim of this study was to systematically estimate the pooled prevalence of MIH. **Methods:** A comprehensive literature research was completed in English and Chinese databases. Random effect models were used to calculate the pooled prevalence. To address the heterogeneity, meta-regression, and sensitivity analyzes were conducted. Publication bias was estimated by trim and fill method. **Results:** Seventy eligible studies were included. The pooled prevalence of MIH was 14.2% globally. In subgroup analysis, South America (18.0%, 95% CI: 13.8-22.2) and Spain (21.1%, 95% CI: 17.7-24.6) had the highest prevalence. There was no significant difference between males (14.3%, 95% CI: 12.0-16.6) and females (14.4%, 95% CI: 12.8-15.9). The prevalence of MIH among children 10 years of age or younger (15.1%, 95% CI: 12.1-18.2) was much higher than the prevalence of MIH among older children (12.1%, 95% CI: 8.0-16.3). Sample size explained 15.7% heterogeneity. **Conclusion:** MIH has a high incidence globally, especially among children <10 years old. It is, therefore, imperative to develop more appropriate dental healthcare strategies to care for these children and to identify the etiology of MIH to prevent it occurring. **14%** **or** **1 in 7** #### Systematic Review Findings (Zhao et al. 2018) - **Pooled Global Prevalence**: 14.2% (approximately 1 in 7 children). - **Regional Highs**: South America (18.0%) and Spain (21.1%). - **Demographics**: - No significant difference between males (14.3%) and females (14.4%). - Higher prevalence in children ≤10 years old (15.1%) compared to older children (12.1%). **Conclusion**: MIH has a high global incidence, necessitating appropriate dental healthcare strategies and further aetiological research. **Aetiology** - **Unknown** - **Pre-natal events** (Lygidakis et al 2008) — Mother hypertension — Drugs during delivery e.g. N₂O — Assisted delivery/emergency caesarian - **Peri-natal events** (Alaluusua 2010) — Foetal distress — Oxygen deprivation — Low birth weight / high birth weight/ premature birth #### Known and Suspected Factors - **General Status**: Unknown #### Pre-natal Events - Mother hypertension - Drugs during delivery (e.g., N₂O) - Assisted delivery or emergency caesarian #### Peri-natal Events - Foetal distress - Oxygen deprivation - Birth weight issues (low or high birth weight, premature birth) **Aetiology** Postnatal factors - Environmental toxins (Jalevik et al. 2001) - Disturbances in the calcium/phosphate metabolism (Jontell and Lindhe 1986) - Prolonged use of antibiotics (Jalevik et al. 2001) - Otitis media (Jalevik et al. 2001) - Frequent febrile childhood disease (Jalevik et al. 2001) - Respiratory disease including asthma (Jalevik et al. 2001) - Genetic predisposition (SCUBE1 gene being shown to be associated with MIH) (Kuhnish et al. 2014) #### Postnatal Factors - Environmental toxins - Disturbances in calcium/phosphate metabolism - Prolonged use of antibiotics - Otitis media - Frequent febrile childhood disease - Respiratory disease, including asthma - Genetic predisposition (e.g., SCUBE1 gene association) **Clinical Features** MIH presents as demarcated enamel defects can be seen as an abnormality in the translucency of the enamel (opacity). (Weerheijm et al. 2001 and 2003) **Severity of MIH vary greatly** - Demarcated opacities - May or may not be associated with post eruptive enamel breakdown (PEB) - Symmetrical: may be symmetrical or asymmetrical - Color: white, creamy yellow, yellow, yellow brown or brown - No. of molars affected: 1 to 4 - Incisors: may not be affected in mild cases or minimally affected - Sensitive to cold, heat and tooth brushing (Fagrell 2008) #### Clinical Presentation MIH presents as demarcated enamel defects seen as abnormalities in enamel translucency (opacity). #### Variability in Severity - **Opacities**: Demarcated opacities that may or may not be associated with post-eruptive enamel breakdown (PEB). - **Symmetry**: May be symmetrical or asymmetrical. - **Coloration**: White, creamy yellow, yellow, yellow-brown, or brown. - **Distribution**: Affects 1 to 4 molars; incisors may be unaffected or minimally affected in mild cases. - **Symptoms**: Sensitivity to cold, heat, and tooth brushing. **Composition** * **Darker lesion:** less mineral (↓ Ca/P; ↑ carbon) * **Brown enamel:** a 15–21-fold higher protein content than sound enamel * **White/opaque and yellow enamel:** eight times higher protein content than sound enamel * Protein found in MIH enamel is mainly serum proteins such as: – Albumin – alpha-1-antitrypsin and antithrombin III Mahoney & Farah, 2014 #### Chemical and Protein Analysis - **Darker lesions**: Lower mineral content (decreased Ca/P; increased carbon). - **Brown enamel**: 15–21-fold higher protein content than sound enamel. - **White/opaque and yellow enamel**: 8 times higher protein content than sound enamel. #### Protein Types Proteins found in MIH enamel are primarily serum proteins, including: - Albumin - Alpha-1-antitrypsin - Antithrombin III (Mahoney & Farah, 2014) **Management** The University of Western Australia **Problems related with management** • Large immature pulps • Crown height reduced • Difficult in achieving profound anaesthesia • Enamel quality may preclude good bonding • Restoration retention difficult • Dental caries may progress faster #### Challenges in Clinical Management - Large immature pulps - Reduced crown height - Difficulty in achieving profound anaesthesia - Poor enamel quality affecting bonding - Difficulty with restoration retention - Faster progression of dental caries  Cross-section micrograph of an MIH-affected first permanent molar showing enamel structure. Labels indicate 'Last Indent', 'Line of indentations' (spaced 250 μm parallel to adjacent dentin), and 'First Indent'. A bracket highlights a 'Transition Zone' between 'Hypomineralised Enamel' and 'Unaffected Enamel'. Source: Mahoney & Farah, 2014. # Prevention* ![The University of Western Australia logo]() * *Appropriate dietary advice* * *Use of fluoride* * *Fluoride tooth paste (1000 ppm)* * *Fluoride varnish* * *Fluoride mouthwashes* * *CPP-ACP* * *Sugar free gums* * *Fissure sealants* * *Recall appointments* (William et al. 2006; Willmott et al. 2008) \*Prevention of sensitivity, PEB, secondary caries #### Preventive Measures Focus on preventing sensitivity, post-eruptive breakdown (PEB), and secondary caries: - **Dietary Advice**: Appropriate nutritional counseling. - **Fluoride Therapy**: - Fluoride toothpaste (1000 ppm) - Fluoride varnish - Fluoride mouthwashes - **Remineralisation**: CPP-ACP (Casein Phosphopeptide-Amorphous Calcium Phosphate). - **Adjuncts**: Sugar-free gums. - **Protection**: Fissure sealants. - **Maintenance**: Regular recall appointments. (William et al. 2006; Willmott et al. 2008) # Management of Sensitivity * **Plaque removal** (using soft tooth brush and warm water) * **Use of fluoride** (Fluoride tooth paste 1000 ppm; Fluoride varnish; Fluoride mouthwashes) * **CPP-ACP** (Tooth mousse Plus) * **Desensitizing tooth paste** (Pro-Argin; Colgate) * Sealing with resin * Sealing with GIC * Resin infiltration * Compomers #### Sensitivity Control Options - **Plaque removal**: Using a soft toothbrush and warm water. - **Fluoride application**: Toothpaste (1000 ppm), varnish, and mouthwashes. - **Remineralising agents**: CPP-ACP (e.g., Tooth Mousse Plus). - **Desensitizing agents**: Pro-Argin (Colgate). - **Sealing and Infiltration**: - Sealing with resin or Glass Ionomer Cement (GIC) - Resin infiltration - Compomers # Restorative Management * Resin composite * Polyacid modified composite resins (compomers) * Glass inomers * Resin modified glass ionomers * Stainless steel crowns SSC's * Cast metal restoration- Gold or semi-precious metal onlays * Porcelain fused to metal crowns THE UNIVERSITY OF WESTERN AUSTRALIA (Harley, 1999; Mejare et al. 2005; Kotsanos et al. 2003) #### Materials and Techniques - Resin composite - Polyacid modified composite resins (compomers) - Glass ionomers and Resin-modified glass ionomers - Stainless steel crowns (SSCs) - Cast metal restorations (Gold or semi-precious metal onlays) - Porcelain fused to metal crowns (Harley, 1999; Mejare et al. 2005; Kotsanos et al. 2003) # Restorative Management      Clinical photo of the maxillary arch showing multiple teeth with discoloration and restorations. A red circle highlights a molar in the posterior region exhibiting significant carious lesions or decay. Lateral view of the lower anterior dentition showing spacing between incisors and potential restorative work on the central incisors. Frontal view of the maxillary anterior dentition showing alignment and condition of central and lateral incisors. Lateral view of the maxillary right dentition showing occlusion and tooth morphology. Clinical photo of the mandibular arch showing multiple teeth with varying degrees of wear and restorations. A red circle highlights a molar in the posterior region with visible caries or structural damage. Restorative Management **THE UNIVERSITY OF WESTERN AUSTRALIA**      Restorative Management Clinical intraoral photograph showing the maxillary occlusal view. The image displays the upper dental arch with a prominent silver amalgam restoration on the right posterior tooth (patient's left). The title 'Restorative Management' is visible at the top. Clinical intraoral photograph showing the left buccal segment of the dentition. It highlights crowding and malocclusion in the anterior region, specifically involving the premolars and canines. Clinical intraoral photograph showing the frontal view of the maxillary and mandibular anterior teeth. This view demonstrates significant anterior crowding and irregular alignment of both arches. Clinical intraoral photograph showing the right buccal segment of the dentition. It provides a view of the molars and premolars, showing the occlusal relationship between the upper and lower teeth. Clinical intraoral photograph showing the mandibular occlusal view. Similar to the maxillary view, it features a large silver amalgam restoration on the right posterior tooth. **Management with Extractions** Decision based on following: • Degree & extend of hypomineralisation/hypoplasia • Post-eruptive breakdown • Sensitivity • Age & co-operation of the child • Any developing malocclusion • No. of teeth missing/present (third molars) #### Criteria for Extraction Decisions - Degree and extent of hypomineralisation/hypoplasia - Presence of post-eruptive breakdown - Level of sensitivity - Age and cooperation of the child - Developing malocclusion - Number of teeth present or missing (including third molars) Management with Extractions **The University of Western Australia** Three main options: 1. Immediate extraction: infective, severely broken down 2. Delay extraction to optimize the eruption of surrounding teeth (to allow 7's to move in their place) 3. Extract them as part of orthodontics #### Timing and Strategic Options 1. **Immediate extraction**: For infective or severely broken down teeth. 2. **Delayed extraction**: To optimize the eruption of surrounding teeth (allowing second molars to move into the first molar space). 3. **Orthodontic extraction**: Planned as part of comprehensive orthodontic treatment. # Management with Extractions * **Class II malocclusion** * **Deep bite** * **Lip trap** * **Brachyfacial type** * **Spacings** #### Orthodontic Considerations - Class II malocclusion - Deep bite - Lip trap - Brachyfacial type - Spacings **Management with Extractions** Panoramic radiograph of 9-year-old female with an orthodontic plan to have all first molars extracted (severe hypomineralisation). Note positions of lower second premolars Drummond & Harding, 2014  #### Case Study: 9-Year-Old Female Panoramic radiograph showing an orthodontic plan for extraction of all first molars due to severe hypomineralisation. Note the positions of the lower second premolars. (Drummond & Harding, 2014) Panoramic radiograph of a 9-year-old female showing severe hypomineralisation (white spots) on the upper first molars. The image is relevant to an orthodontic plan for extraction of these teeth. Management with Extractions Panoramic 3 years after the extractions. Note eruption paths of lower second premolars Drummond & Harding, 2014  #### Follow-up: 3 Years Post-Extraction Panoramic radiograph showing the eruption paths of the lower second premolars following the extractions. (Drummond & Harding, 2014) Clinical panoramic radiograph showing the dentition 3 years after extractions. The image demonstrates the eruption paths of the lower second premolars, with visible root development and alignment relative to adjacent teeth. A radiopaque restoration is present on a molar in the upper right quadrant. # Management of Anterior Teeth **Permanet teeth** - Micro-abrasion (with or without bleaching) - PMMA resin - Composite veneers - Zirconia veneers/ crowns (Ashkenazi and Sarnat ,2000; Welbury 1991; Wong and Winter, 2002; Wright, 2002) #### Treatment Options for Permanent Anterior Teeth - Micro-abrasion (with or without bleaching) - PMMA resin - Composite veneers - Zirconia veneers or crowns (Ashkenazi and Sarnat, 2000; Welbury 1991; Wong and Winter, 2002; Wright, 2002) **Management of Anterior Teeth** **- Microabrasion** **THE UNIVERSITY OF WESTERN AUSTRALIA** a b Hanlin et al. 2014   #### Microabrasion Technique Visual representation of microabrasion results on anterior teeth. (Hanlin et al. 2014) Clinical photo labeled 'a' showing the anterior dentition before microabrasion treatment. The maxillary central incisors exhibit significant white spot lesions and surface irregularities. Clinical photo labeled 'b' showing the same anterior teeth after microabrasion treatment. The enamel surfaces appear smoother and more uniform in color compared to image 'a'. Reference text 'Hanlin et al. 2014' is present at the bottom right. **Management of Anterior Teeth – Composite veneers** a b The University of Western Australia Hanlin et al. 2014   #### Composite Veneers Visual representation of composite veneer application on anterior teeth. (Hanlin et al. 2014) Clinical photo (labeled 'a') showing the pre-treatment condition of anterior teeth. The central incisors exhibit severe discoloration with a yellow-brown hue and surface irregularities, consistent with enamel hypoplasia or fluorosis. Surrounding teeth show mild crowding. Clinical photo (labeled 'b') showing the post-treatment result after composite veneers application. The anterior teeth now display uniform, bright white coloration and smooth surfaces, effectively masking the previous defects and improving aesthetics. # Management Decisions **THE UNIVERSITY OF WESTERN AUSTRALIA** ## Extraction * **Immediate** * Severe pain or infection * **Intermediate** * Extract when 7's are in correct position * Manage sensitivity, pulp, enamel fractures * **Long term** * Extract as part of ortho treatment * Manage sensitivity, pulp, enamel fractures ## Long Term restoration * **Immediate** * Compomer, SSC, GIC * **Intermediate** * SSC, Composite * **Long term** * Gold /metal overlay, full crowns #### Extraction Pathways - **Immediate**: Required for severe pain or infection. - **Intermediate**: Extract when second molars (7's) are in the correct position; manage sensitivity and enamel fractures in the interim. - **Long term**: Planned orthodontic extraction; interim management of pulp and sensitivity. #### Restorative Pathways - **Immediate**: Compomer, SSC, or GIC. - **Intermediate**: SSC or Composite. - **Long term**: Gold/metal overlays or full crowns. <table><tbody><tr><td colspan="1"><b>Mild Defects</b></td><td colspan="1"><b>Moderate/Severe Defects</b></td></tr><tr><td colspan="1">Enamel opacities (white/yellow), no post-eruptive breakdown, no/slight sensitivity, mild aesthetic problems, no secondary caries</td><td colspan="1">Enamel opacities (brown), post-eruptive breakdown, atypical restorations, sensitivity, secondary caries, aesthetic problems</td></tr><tr><td><i>Molars</i></td><td><i>Incisors</i></td><td><i>Molars</i></td><td><i>Incisors</i></td></tr><tr><td>Application of fluoride varnish and consider use of CPP-ACP products for home use</td><td>In whiteish defects; microabrasion or resin infiltration and if needed this can be followed by a resin composite restoration</td><td>Early referral to specialist paediatric dental services (ideally before 8 years of age)</td><td>Resin composite restorations or veneers following micro-abrasion, reduction and intermediate opaque resins</td></tr><tr><td>Fissure Sealants of partially erupted teeth with glass-ionomer cements and resin composite sealants of erupted teeth using adequate isolation</td><td>In yellow-brown defects; etch-bleach-seal technique</td><td>Consider extractions following multidisciplinary paediatric and orthodontic consultation</td><td>Porcelain veneers, if required, in adulthood</td></tr><tr><td>Resin composite restorations with adequate isolation if localised breakdown or secondary caries is observed*</td><td>Resin composite restorations with conservative enamel reduction</td><td>Full coverage restorations including stainless steel crowns in children and adolescents</td><td></td></tr><tr><td colspan="5">Ongoing preventive care and clinical reviews for all cases</td></tr></tbody></table> *Multi-surface glass ionomer restorations are NOT recommended  #### Severity-Based Management Matrix | Feature | Mild Defects | Moderate/Severe Defects | | :--- | :--- | :--- | | **Clinical Signs** | White/yellow opacities, no PEB, slight sensitivity, no secondary caries. | Brown opacities, PEB, atypical restorations, sensitivity, secondary caries. | | **Molar Treatment** | Fluoride varnish, CPP-ACP, fissure sealants (GIC for partial eruption, resin for full), composite if breakdown occurs.* | Early specialist referral (<8 years), consider extractions (ortho consult), SSCs for children/adolescents. | | **Incisor Treatment** | White defects: Microabrasion or resin infiltration ± composite. Yellow-brown: Etch-bleach-seal. | Composite restorations/veneers after microabrasion and opaque resins. Porcelain veneers in adulthood. | *Note: Multi-surface glass ionomer restorations are NOT recommended for molars with breakdown. A structured clinical table titled 'Management strategies for hypomineralised teeth (revised Dec 2018)'. The table compares management options for Mild Defects versus Moderate/Severe Defects. It is subdivided by tooth type (Molars vs Incisors). Specific treatments listed include fluoride varnish, fissure sealants, microabrasion, resin infiltration, and stainless steel crowns. A footnote indicates multi-surface glass ionomer restorations are NOT recommended. **Eur Arch Paediatr Dent.** 2017 Dec;18(6):377-383. doi: 10.1007/s40368-017-0306-8. Epub 2017 Oct 28. ## Tooth mineral density of different types of hypomineralised molars: a micro-CT analysis **C Neboda** 1, **R P Anthonappa** 2, **N M King** 1 *Affiliations + expand* **PMID:** 29081019 **DOI:** 10.1007/s40368-017-0306-8 **Abstract** **Aim:** This study sought to evaluate the tooth mineral density (TMD) for the different lesion types in hypomineralised first permanent molars (FPMs) and compare them to unaffected enamel in clinically sound FPMs. **Design:** Eighteen FPMs with varying degrees of hypomineralised enamel were grouped into brown, yellow/creamy and white lesion types. Micro-CT was used to determine the TMD for each lesion type, and for unaffected enamel at different locations in the outer, middle, and inner-third of the enamel. **Results:** The average TMD for brown, yellow/creamy, white and unaffected enamel was 1.79, 2.21, 2.43 and 2.46 g/cm³, respectively. Brown and yellow/creamy lesions exhibited a statistically significant difference when compared to white lesions and unaffected enamel. However, no statistical difference was evident in TMD between white lesions and unaffected enamel. The TMD increased from the outer-third to inner-third for brown and yellow/creamy lesions (p < 0.05), while in white lesions and unaffected enamel, the TMD decreased from the outer-third to inner-third (p < 0.05). **Conclusion:** TMD was lowest for brown lesions followed by yellow/creamy lesions while the TMD for white lesions was similar to unaffected enamel. **Keywords:** Hypomineralisation; Molar-incisor hypomineralisation; Permanent molars; Tooth mineral density.  #### Tooth Mineral Density (TMD) Analysis (Neboda et al. 2017) - **Study Aim**: Evaluate TMD for different lesion types in hypomineralised first permanent molars (FPMs) using micro-CT. - **Average TMD Results**: - Unaffected Enamel: 2.46 g/cm³ - White Lesions: 2.43 g/cm³ - Yellow/Creamy Lesions: 2.21 g/cm³ - Brown Lesions: 1.79 g/cm³ - **Key Findings**: - Brown and yellow lesions have significantly lower density than sound enamel. - White lesions have a TMD similar to unaffected enamel. - TMD increases from outer to inner enamel in brown/yellow lesions, but decreases in white/sound enamel. Composite figure displaying four enamel lesion types (Clinically Normal Enamel, Chalky White, Creamy Yellow, Brown) with corresponding micro-CT cross-sections. Each panel includes a clinical photo of the tooth surface and an adjacent color-coded micro-CT scan showing mineral density variations. Labels indicate statistical significance (P<0.05) for creamy yellow and brown lesions. **Hypomineralised Second Primary Molars!** * Prevalence: ~10% (14% reported by a recent Australian study) Owen et al. 2017 * Are hypomineralised lesions on second primary molars (**_HSPM_**) a predictive sign of molar incisor hypomineralisation (**MIH**)? * OR 4.66, Co-occurence prevalence ~20% Garot et al. 2018 * Association between HSPM and hypomineralised primary canines... #### Prevalence and Predictive Value - **Prevalence**: Approximately 10% (up to 14% in recent Australian data; Owen et al. 2017). - **Predictive Sign**: Hypomineralised Second Primary Molars (HSPM) are associated with MIH (OR 4.66, co-occurrence ~20%; Garot et al. 2018). - **Associations**: Linked with hypomineralised primary canines.   Dental radiograph (X-ray) showing a section of the mandibular posterior teeth. Visible are molar crowns and roots with intact lamina dura, and adjacent alveolar bone trabeculation. A small dark artifact or marker is visible near the inferior aspect of the image. Dental radiograph (X-ray) displaying mandibular posterior teeth with well-defined root structures and periodontal ligament spaces. A circular metallic density (likely a fiducial marker or screw head) is present in the superior aspect of the field of view. Hypomineralised Second Primary Molars (HSPM) is a condition characterized by qualitative enamel defects in one to four second primary molars. This condition is considered a significant predictor for the development of Molar Incisor Hypomineralisation (MIH) in the permanent dentition. #### Clinical Presentation and Diagnosis - The clinical appearance of HSPM is similar to MIH, presenting as demarcated opacities that vary in color from white and yellow to brown. - These defects are often associated with rapid post-eruptive enamel breakdown due to the decreased mineral density of the affected enamel. - Diagnosis is typically made through visual inspection of the second primary molars once they have erupted into the oral cavity. #### Relationship with MIH - Research indicates a strong correlation between the presence of HSPM and the subsequent occurrence of MIH in the permanent first molars and incisors. - Children identified with HSPM are at a higher risk for dental caries and sensitivity in the primary dentition, requiring early monitoring and preventive interventions. #### Management Strategies - **Prevention:** Application of topical fluorides and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) to promote remineralization. - **Restoration:** Use of adhesive materials such as glass ionomer cements or composite resins to manage enamel breakdown and protect the tooth structure. - **Long-term Monitoring:** Regular dental check-ups to assess the transition from primary to permanent dentition and manage any emerging MIH symptoms. Practical Paediatrics **Dr Jilen Patel**  Practical Paediatrics **Dr Jilen Patel** Clinical intraoral photographs of a paediatric patient's dentition. The top panel shows the maxillary arch with significant carious lesions on the primary molars (stained orange/brown) and decayed permanent first molars. The bottom panel displays the mandibular arch with similar severe dental caries on the posterior teeth. Text in the upper right corner reads 'Practical Paediatrics Dr Jilen Patel'. ### Abstract **Objective:** A growing number of studies have investigated the prevalence of Molar Incisor Hypomineralization (MIH) around the word. The aim of this study was to systematically estimate the pooled prevalence of MIH. **Methods:** A comprehensive literature research was completed in English and Chinese databases. Random effect models were used to calculate the pooled prevalence. To address the heterogeneity, meta-regression, and sensitivity analyses were conducted. Publication bias was estimated by trim and fill method. **Results:** Seventy eligible studies were included. The pooled prevalence of MIH was 14.2% globally. In subgroup analysis, South America (18.0%, 95% CI: 13.8-22.2) and Spain (21.1%, 95% CI: 17.7-24.6) had the highest prevalence. There was no significant difference between males (14.3%, 95% CI: 12.0-16.6) and females (14.4%, 95% CI: 12.8-15.9). The prevalence of MIH among children 10 years of age or younger (15.1%, 95% CI: 12.1-18.2) was much higher than the prevalence of MIH among older children (12.1%, 95% CI: 8.0-16.3). Sample size explained 15.7% heterogeneity. **Conclusion:** MIH has a high incidence globally, especially among children <10 years old. It is, therefore, imperative to develop more appropriate dental healthcare strategies to care for these children and to identify the etiology of MIH to prevent it occurring.  #### Global Prevalence of Molar Incisor Hypomineralization (MIH) **Objective** A growing number of studies have investigated the prevalence of Molar Incisor Hypomineralization (MIH) around the world. The aim of this study was to systematically estimate the pooled prevalence of MIH. **Methods** A comprehensive literature research was completed in English and Chinese databases. Random effect models were used to calculate the pooled prevalence. To address the heterogeneity, meta-regression, and sensitivity analyses were conducted. Publication bias was estimated by trim and fill method. **Results** - Seventy eligible studies were included. - The pooled prevalence of MIH was 14.2% globally. - Subgroup analysis: South America (18.0%) and Spain (21.1%) had the highest prevalence. - Gender: No significant difference between males (14.3%) and females (14.4%). - Age: Prevalence among children 10 years of age or younger (15.1%) was higher than among older children (12.1%). - Sample size explained 15.7% of heterogeneity. **Conclusion** MIH has a high incidence globally, especially among children <10 years old. It is, therefore, imperative to develop more appropriate dental healthcare strategies to care for these children and to identify the etiology of MIH to prevent it occurring. Clinical intraoral photograph showing the maxillary arch of a patient. The image displays severe dental pathology consistent with Molar Incisor Hypomineralization (MIH). A close-up inset highlights a molar tooth exhibiting extensive yellow-brown discoloration and structural defects on the occlusal surface. Additionally, there is visible carious decay (dark brown lesion) on the mesial aspect of an adjacent premolar. RIGHT Dr Jilen Patel JUDGEMENT CRITERIA Weerheijm et al. 2003 | Criteria | Definition | | --- | --- | | **Demarcated opacity** | A demarcated defect involving an alteration in the translucency of the enamel, variable in degree. The defective enamel is of normal thickness with a smooth surface and can be white, yellow or brown in colour. | | **Posteruptive Enamel Breakdown (PEB)** | A defect that indicates deficiency of the surface after eruption of the tooth. Loss of initially formed surface enamel after tooth eruption. The loss is often associated with a pre-existing demarcated opacity. | | **Atypical restoration** | The size and shape of restoration are not conform the temporary caries picture. In most cases in molars it will handle about restorations extended to the buccal or palatal smooth surface. At the border of the restorations frequently an opacity can be noticed. In incisors a buccal restoration can be noticed not related to a trauma. | | **Extracted molar due to MIH** | Absence of a first permanent molar should be related to the other teeth of the dentition. Suspected for extraction due to MIH are: opacities or atypical restorations in the other first permanent molars combined with absence of a first permanent molar. Also the absence of first permanent molars in a sound dentition in combination with demarcated opacities on the incisors is suspected for MIH. It is not likely that incisors will be extracted due to MIH. | | **Unerupted** | The first permanent molar or the incisor to be examined are not yet erupted. | Notes: in case of a large caries lesion with demarcated opacities at the border of the cavity or on the non caries surfaces these teeth should be judged as MIH. Other changes in dental enamel such amelogenesis imperfecta, hypoplasia, diffuse opacities, white spot lesions, tetracycline staining, erosion, fluorosis, white cusp and marginal ridges should be excluded from the types of enamel defects outlined as above. **TABLE 1** - Definitions of the judgement criteria to be used in diagnosing *Molar Incisor Hypomineralisation (MIH)* for prevalence studies.    #### Judgement Criteria (Weerheijm et al. 2003) | Criteria | Definition | | :--- | :--- | | **Demarcated opacity** | A demarcated defect involving an alteration in the translucency of the enamel, variable in degree. The defective enamel is of normal thickness with a smooth surface and can be white, yellow or brown in colour. | | **Posteruptive Enamel Breakdown (PEB)** | A defect that indicates deficiency of the surface after eruption of the tooth. Loss of initially formed surface enamel after tooth eruption. The loss is often associated with a pre-existing demarcated opacity. | | **Atypical restoration** | The size and shape of restoration do not conform to the temporary caries picture. In molars, restorations often extend to the buccal or palatal smooth surface. Opacities are frequently noticed at the borders. In incisors, buccal restorations may be noticed unrelated to trauma. | | **Extracted molar due to MIH** | Absence of a first permanent molar related to other teeth. Suspected if other first permanent molars have opacities/atypical restorations, or if a sound dentition has demarcated opacities on incisors. | | **Unerupted** | The first permanent molar or the incisor to be examined are not yet erupted. | **Diagnostic Notes** - Large caries lesions with demarcated opacities at the border or on non-caries surfaces should be judged as MIH. - Exclude other enamel changes: amelogenesis imperfecta, hypoplasia, diffuse opacities, white spot lesions, tetracycline staining, erosion, fluorosis, white cusp, and marginal ridges. Clinical photo of the maxillary dentition showing a close-up view of a molar with significant yellow-brown opacities and defects on the occlusal surface. A dental mirror is visible retracting the cheek to expose the teeth. Clinical photo of the maxillary arch viewed from an occlusal perspective. It displays multiple first permanent molars exhibiting brown discoloration (opacities) and restoration materials. One molar shows a large defect or cavity preparation. Table 1 - Definitions of the judgement criteria to be used in diagnosing Molar Incisor Hypomineralisation (MIH) for prevalence studies. The table lists five criteria: Demarcated opacity, Posteruptive Enamel Breakdown (PEB), Atypical restoration, Extracted molar due to MIH, and Unerupted, providing specific definitions for each based on Weerheijm et al. 2003. Practical Paediatrics **Dr Jilen Patel** **Ultra-structural considerations** Rodd et al. 2007 Pulpal expression of TRPV1 in molar incisor hypominalisation H D Rodd 1 , C R Morgan, P F Day, F M Boissonade Affiliations + expand PMID: 136726848 **DOI: 10.1007/BF03262594** **Abstract** **Aim:** This was to compare the pulpal expression of the transient receptor potential ion channel (TRPV1), a noxious heat receptor, in sound and hypomineralised human first permanent molars. The rationale for the investigation was to gain further insight into pulpal changes in hypomineralized teeth and the possible biological mechanisms underlying thermal hypersensitivity. **Study design:** This was a laboratory study using a quantitative immunofluorochemical approach. **Methods:** The experimental material comprised 17 sound and 18 hypomineralised molars (10 with intact enamel and 8 with enamel loss), obtained from children requiring dental extractions under general anaesthesia. Coronal pulps were removed and processed for indirect immunofluorescence using antibodies raised against TRPV1 and either the general neuronal marker, protein gene-product 9.5 or alpha smooth muscle actin in conjunction with Ulex europaeus agglutinin 1 lectin to fully label the pulp vasculature. Computerized image analysis was used to quantify the expression of TRPV1 in both pulp nerves and blood vessels within different regions of the pulp including the pulp horn, subodontoblastic plexus and mid-coronal region. **Results:** Mean neuronal and vascular TRPV1 expression was greater in the pulps of hypomineralised teeth (both with and without enamel loss in comparison to sound samples (p<0.05, ANOVA). **Conclusions:** Increased TRPV1 expression within the pulps of hypomineralised teeth may be indicative of an underlying pulp inflammation and may help to explain the heat sensitivity experienced by some patients with this condition. However, future lines of enquiry should seek to correlate patient symptoms and responses to controlled hot and cold stimuli with TRPV1 expression of a variety of thermal receptors to gain further insight into dental pain mechanisms.    #### Pulpal Expression of TRPV1 in MIH (Rodd et al. 2007) **Aim** To compare the pulpal expression of the transient receptor potential ion channel (TRPV1), a noxious heat receptor, in sound and hypomineralised human first permanent molars to gain insight into biological mechanisms underlying thermal hypersensitivity. **Methods** - Material: 17 sound and 18 hypomineralised molars (10 intact enamel, 8 with enamel loss). - Approach: Quantitative immunofluorochemical analysis of coronal pulps using antibodies against TRPV1, neuronal marker PGP 9.5, and vascular markers. - Analysis: Quantification of TRPV1 in pulp nerves and blood vessels (pulp horn, subodontoblastic plexus, and mid-coronal region). **Results** Mean neuronal and vascular TRPV1 expression was significantly greater in the pulps of hypomineralised teeth (both with and without enamel loss) compared to sound samples (p<0.05). **Conclusions** Increased TRPV1 expression may indicate underlying pulp inflammation and help explain heat sensitivity. Future research should correlate patient symptoms with various thermal receptors. Clinical photo: A close-up intraoral view of a hypomineralised molar tooth. The image shows the occlusal surface with distinct white/opaque enamel defects and yellowish discoloration, set against pink gingival tissue. Clinical photo: An intraoral view showing multiple teeth in an arch, likely illustrating the clinical presentation of molar incisor hypomineralisation (MIH) affecting adjacent molars. Chart: A composite figure containing three bar charts (A, B, C) comparing quantitative immunofluorescence data across three pulp regions (Pulp horn, Subodontoblastic plexus, Mid-coronal region). Panel A shows 'Innervation density' (% area PGP 9.5), Panel B shows 'Leucocyte accumulation' (% area LCA), and Panel C shows 'Vascularity' (% area UEIL). All charts compare Sound, Hypomineralized (enamel intact), and Hypomineralized (enamel loss) groups using grey bars, with asterisks indicating statistical significance. **Practical Paediatrics** **Dr Jilen Patel** ## Ultra-structural considerations Fagrell et al. 2008 --- **Bacterial invasion of dentinal tubules beneath apparently intact but hypomineralized enamel in molar teeth with molar incisar hypomineralization** Tobias G Fagrell, Peter Lingström, Stina Olsson, Frank Steiniger, Jörgen G Norén **Abstract** **Background:** The most common problems for a patient with molar incisar hypomineralization (MIH) are the collapse of enamel and cavitations, loss of fillings, and secondary caries, but most of all, severe hypersensitivity. **Objective:** The aim of this paper was therefore to histologically study possible bacterial invasion of dentinal tubules beneath apparently intact, but hypomineralized enamel in permanent molars with MIH. **Material and methods:** Five extracted permanent first molars diagnosed with MIH were fixed, demineralized, and sagittally serially sectioned in a bucco-lingual direction in a microtome with a thickness of 4-5 microm. Sections were stained with a modified Brown and Brenn staining for bacteria, unstained sections were analysed in field emission SEM. **Results:** Stained sections from the cuspal areas, below the hypomineralized enamel, the staining indicated the presence of bacteria in the dentinal tubules. The HTX staining showed that the pulp in sections without any findings was normal and free from bacteria or infiltrates from inflammatory cells. In sections where bacteria were found in the cuspal areas or deeper in the dentin, a zone of reparative dentin was found, and in sections from one tooth, the coronal pulp showed an inflammatory reaction with inflammatory cells. In sections adjacent to those without any bacterial staining, the SEM analyses revealed empty dentinal tubules without any odontoblast processes or signs of bacteria. When odontoblast processes were found, the dentinal tubules were filled with bacteria located on the surface of the odontoblast processes. In some areas, a large number of tubules were found with bacteria. No bacteria were found close to the pulp. The odontoblast processes appeared larger in areas where bacteria were found. **Conclusions:** The presence of bacteria in the dentinal tubules and inflammatory reactions in the pulp indicate that oral bacteria may penetrate through the hypomineralized enamel into the dentin, thus possibly contribute to hypersensitivity of teeth with MIH. **Figure 2. Low-magnification SEM image of a permanent first molar with normal and hypomineralized enamel. NE = normal enamel; HM = hypomineralized enamel; D = dentin.**   #### Bacterial Invasion of Dentinal Tubules (Fagrell et al. 2008) **Objective** To histologically study possible bacterial invasion of dentinal tubules beneath apparently intact but hypomineralized enamel in permanent molars with MIH. **Material and Methods** Five extracted permanent first molars with MIH were fixed, demineralized, and sagittally sectioned. Sections were analyzed using modified Brown and Brenn staining and field emission SEM. **Results** - **Bacterial Presence:** Staining indicated bacteria in dentinal tubules in cuspal areas below hypomineralized enamel. - **Pulpal Reaction:** Sections with bacteria showed reparative dentin; one tooth showed an inflammatory reaction in the coronal pulp. Pulps in sections without bacteria appeared normal. - **SEM Findings:** Bacteria were found on the surface of odontoblast processes within the tubules. No bacteria were found close to the pulp. Odontoblast processes appeared larger in areas where bacteria were present. **Conclusions** Oral bacteria may penetrate through hypomineralized enamel into the dentin, contributing to pulpal inflammation and hypersensitivity in MIH teeth. Clinical photograph showing a close-up intraoral view of a molar tooth exhibiting severe molar incisor hypomineralization (MIH). The occlusal surface reveals significant enamel defects with discoloration and structural irregularities. Low-magnification Scanning Electron Microscope (SEM) image of a permanent first molar cross-section. The figure displays three labeled regions: HM (hypomineralized enamel), NE (normal enamel), and D (dentin). A scale bar indicates 2 mm. This visual demonstrates the ultra-structural relationship between normal and hypomineralized enamel layers in a tooth diagnosed with MIH. **Practical Paediatrics** **Dr Jilen Patel** # Behavioural considerations Jälevik et al. 2012 **Comparative Study** **Int J Paediatr Dent.** 2012 Mar;22(2):85-91. doi: 10.1111/j.1365-263X.2011.01161.x. Epub 2011 Jul 22. **Treatment outcomes and dental anxiety in 18-year-olds with MIH, comparisons with healthy controls – a longitudinal study** Birgitta Jälevik ${}^{1}$, Gunilla Klingberg Affiliations + expand PMID: 21781199 DOI: 10.1111/j.1365-263X.2011.01161.x **Abstract** **Background:** In a previous study, 9-year-old children with severe Molar Incisor Hypomineralization (MIH) had undergone dental treatment of their first molars nearly ten times as often as children in a control group. They also showed more management problems (BMP) and fear and anxiety (DFA). ** Aim:** To assess the long-term outcomes of dental treatments, dental anxiety, and patients' satisfaction in adolescents with MIH. **Design:** Sixty-seven patients, identical with those in the baseline study, were studied at age 18-years. The participants answered the Children's Fear Survey Schedule - Dental Subscale the Dental Visit Satisfaction Scale (DVSS). Data were compiled from the dental records concerning dental health, number of restorative treatments and BMP. **Results:** Molar Incisor Hypomineralization group had a significantly higher DMFT, and had undergone treatment of their permanent first molars 4.2 times as often as the controls. BMP was still significantly more common in the MIH group. However, DFS was reduced in MIH group and increased in the control groups. The DVSS scores did not differ between the groups. Conclusions. Patients with severe MIH had a poorer dental health and were still more treatment consuming at age 18-years. However, their dental fear was now at the same level as the controls.   #### Treatment Outcomes and Dental Anxiety (Jälevik et al. 2012) **Background** Previous studies showed 9-year-olds with severe MIH underwent treatment ten times more often than controls and exhibited more behavior management problems (BMP) and dental fear and anxiety (DFA). **Aim** To assess long-term outcomes, dental anxiety, and patient satisfaction in adolescents (age 18) with MIH. **Results** - **Treatment Burden:** The MIH group had significantly higher DMFT and had undergone treatment of first permanent molars 4.2 times as often as controls. - **Behavior:** BMP remained significantly more common in the MIH group. - **Anxiety:** Dental fear (DFS) in the MIH group reduced over time and was at the same level as controls by age 18. - **Satisfaction:** Dental Visit Satisfaction Scale (DVSS) scores did not differ between groups. **Conclusions** Patients with severe MIH have poorer dental health and higher treatment consumption into late adolescence, though dental fear levels eventually normalize. Clinical photograph of an upper dental arch showing severe Molar Incisor Hypomineralization (MIH). The image highlights a molar with extensive white and yellow opacities, indicating enamel defects. Another tooth in the arch shows a dark brown cavity or restoration, demonstrating the poor dental health discussed in the study. Clinical photograph of a lower dental arch showing teeth with MIH characteristics, including white spots on the occlusal surfaces. A prominent orange-colored filling is visible on one of the molars, illustrating restorative treatment mentioned in the study's results regarding higher treatment consumption in the MIH group. <div style="text-align: right;"><i>Practical Paediatrics</i><br>Dr Jilen Patel</div> <div style="text-align: center; font-size: large; font-weight: bold; text-shadow: 2px 2px 4px #000;">TREATMENT CRITERIA</div> <div style="text-align: center; margin-bottom: 20px;">Lygidakis et al. 2010</div> <table border="1" style="border-collapse: collapse; width: 100%;"> <thead> <tr> <th rowspan="2">Level of Severity</th> <th colspan="3">Dental Age</th> </tr> <tr> <th>Early Mixed</th> <th>Late Mixed</th> <th>Full permanent</th> </tr> </thead> <tbody> <tr> <td rowspan="4">Mild</td> <td colspan="3" style="text-align:center;">Prevention</td> </tr> <tr> <td colspan="3" style="text-align:center;">Adhesive + sealant for restoration</td> </tr> <tr> <td colspan="3" style="text-align:center;">Composite restoration</td> </tr> <tr> <td colspan="3" style="text-align:center;">Microabrasion, bleach + sealant for anterior</td> </tr> <tr> <td rowspan="6">Severe</td> <td colspan="3" style="text-align:center;">Prevention & symptom control</td> </tr> <tr> <td colspan="3" style="text-align:center;">Adhesive + sealant for posterior</td> </tr> <tr> <td colspan="3" style="text-align:center;">Microabrasion, bleach + sealant for anterior</td> </tr> <tr> <td colspan="3" style="text-align:center;">Glass ionomer restoration</td> </tr> <tr> <td colspan="3" style="text-align:center;">Composite restoration</td> </tr> <tr> <td colspan="3" style="text-align:center;">Porcelain metal crown</td> </tr> <tr> <td style="text-align: center">Orthodontic extraction</td> <td colspan="2" style="text-align:center;">Cast restoration</td> </tr> </tbody> </table>    #### Treatment Criteria (Lygidakis et al. 2010) | Level of Severity | Early Mixed Dentition | Late Mixed Dentition | Full Permanent Dentition | | :--- | :--- | :--- | :--- | | **Mild** | Prevention; Adhesive + sealant; Composite restoration; Microabrasion, bleach + sealant (anterior) | (Same as Early Mixed) | (Same as Early Mixed) | | **Severe** | Prevention & symptom control; Adhesive + sealant (posterior); Microabrasion, bleach + sealant (anterior); Glass ionomer; Composite; Porcelain metal crown | (Same as Early Mixed) | (Same as Early Mixed) | | **Severe (Ext)** | Orthodontic extraction | Cast restoration | Cast restoration | Clinical photograph showing an occlusal view of a maxillary arch with a prominent molar exhibiting extensive decay or restorative material. The image includes a circular inset magnifying the central tooth, highlighting its surface texture and coloration. Clinical photograph showing an occlusal view of a mandibular arch with multiple teeth displaying varying degrees of discoloration and possible carious lesions. The image provides context for the treatment criteria shown in the table. A structured table titled 'TREATMENT CRITERIA' by Lygidakis et al. 2010, summarizing dental treatment options based on severity levels (Mild, Severe) and dental age stages (Early Mixed, Late Mixed, Full permanent). The table lists specific treatments such as prevention, adhesive + sealant, composite restoration, microabrasion, glass ionomer restoration, porcelain metal crown, orthodontic extraction, and cast restoration. TREATMENT Dent Mater. 2018 Feb;34(2):331-340. doi: 10.1016/j.dental.2017.11.015. Epub 2017 Dec 6. Bonding strategies for MIH-affected enamel and dentin Norbert Krämer **Superscript 1 **, Ngoc-Han Nana Bui Khac **Superscript 1 **, Susanne Lücker **Superscript 2 **, Vitus Stachniss **Superscript 3 **, Roland Frankenberger **Superscript 4 ** Affiliations + expand PMID: 29208311 DOI: 10.1016/j.dental.2017.11.015 Abstract Objectives: Aim of the present study was to evaluate resin composite adhesion to dental hard tissues affected by molar incisor hypomineralisation (MIH). Methods: 94 freshly extracted human molars and incisors (53 suffering MIH) were used. 68 teeth (35 with MIH) were used for µ-TBS tests in enamel and dentin, 26 (18 with MIH) for qualitative evaluation. Specimens were bonded with Clearfil SE Bond, Scotchbond Universal, and OptiBond FL. For MIH affected enamel, additional OptiBond FL groups with NaOCl and NaOCl+Icon were investigated. Beside fractographic analysis, also qualitative evaluations were performed using SEM at different magnifications as well as histological sectioning. Results: Highest µ-TBS values were recorded with dentin specimens (ANOVA, mod. LSD, p<0.05). Results were independent of adhesive and dentin substrate (p>0.05). Pre-test failures did not occur in dentin specimens. Sound enamel specimens exhibited significantly higher µ-TBS values than MIH enamel (p<0.05). The two-step self-etch adhesive (Clearfil SE Bond) and the two-step etch-and-rinse adhesive (Scotchbond Universal) showed the lowest values in affected enamel specimens (p<0.05) with most pre-test failures (p<0.05). OptiBond FL on affected enamel showed better results than Clearfil SE Bond (p<0.05). An additional pre-treatment of affected enamel with NaOCl or NaOCl and Icon did not enhance enamel bonding (p>0.05), however, it caused less pre-test failures (p<0.05). Micromorphological analyses revealed that conventional phosphoric acid etching produces a much less pronounced etching pattern in affected enamel and a porous structure as weak link for the resin-enamel bond was identified. Significance: Bonding to porous hypomineralized MIH enamel is the limiting factor in adhesion to MIH teeth. MIH-affected dentin may be bonded conventionally. #### Bonding Strategies for MIH-Affected Enamel and Dentin (Krämer et al. 2018) **Objectives** To evaluate resin composite adhesion to dental hard tissues affected by MIH. **Methods** - 94 extracted teeth (53 with MIH) were tested for micro-tensile bond strength (µ-TBS) and qualitative evaluation. - Adhesives tested: Clearfil SE Bond, Scotchbond Universal, and OptiBond FL. - Enamel pre-treatments: NaOCl and NaOCl + Icon. **Results** - **Dentin:** Results were independent of adhesive and substrate; MIH-affected dentin bonds conventionally. - **Enamel:** Sound enamel had significantly higher µ-TBS than MIH enamel. - **Adhesive Performance:** OptiBond FL performed better on affected enamel than Clearfil SE Bond. Two-step self-etch and two-step etch-and-rinse adhesives showed the lowest values and most pre-test failures. - **Pre-treatment:** NaOCl or Icon did not enhance bond strength but reduced pre-test failures. - **Morphology:** Phosphoric acid etching produces a less pronounced pattern in MIH enamel; the porous structure acts as a weak link. **Significance** Bonding to porous hypomineralized MIH enamel is the limiting factor in adhesion. MIH-affected dentin may be bonded conventionally.   Clinical intraoral photograph (maxillary occlusal view) showing multiple teeth with carious lesions. The right first molar exhibits a large, dark brown/black cavity involving the occlusal surface and distal aspect. Adjacent to it, the second molar shows an orange-red discoloration on the occlusal surface, likely indicating early decay or post-operative staining. The left central incisor also displays some discoloration. Clinical intraoral photograph (mandibular occlusal view) showing multiple teeth with carious lesions. The right first molar has a significant orange-red lesion on its occlusal surface. The left second molar appears relatively intact but may show minor discoloration. Other visible teeth appear healthy. Hypomineralized second primary molars: prevalence data in Dutch 5-year-olds M E C Elfrink Affiliations + expand PMID: 18523388 DOI: 10.1159/000135674 Abstract The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar incisor hypomineralization molars were adapted to score second primary molars. The prevalence of hypomineralized second primary molars (HSPM) was 4.9% at child level and 3.6% at tooth level. Most HSPMs (87%) showed demarcated opacities, followed by posteruptive enamel loss (40%).   #### Hypomineralized Second Primary Molars: Prevalence Data in Dutch 5-Year-Olds **Author:** M. E. C. Elfrink **Reference:** PMID: 18523388 | DOI: 10.1159/000135674 **Study Overview** This cross-sectional observational study aimed to report the prevalence of hypomineralizations in second primary molars among 5-year-old Dutch children. The study included 386 participants (45% girls), all insured by a Health Insurance Fund. **Methodology** Scoring criteria typically used for Molar Incisor Hypomineralization (MIH) were adapted to evaluate second primary molars. **Key Findings** - The prevalence of hypomineralized second primary molars (HSPM) was 4.9% at the child level and 3.6% at the tooth level. - 87% of HSPMs exhibited demarcated opacities. - 40% of HSPMs showed posteruptive enamel loss. Clinical photo showing a close-up of a hypomineralized second primary molar with significant brown discoloration and enamel loss. Clinical photo of the lower dental arch of a child, showing multiple teeth with visible orange-brown lesions consistent with hypomineralization on the occlusal surfaces. Practical Paediatrics Dr Jilen Patel Aust Dent J. 2018 Mar;63(1):72-80. doi: 10.1111/adj.12567. Epub 2017 Oct 26. # Hypomineralized second primary molars: prevalence, defect characteristics and relationship with dental caries in Melbourne preschool children M L Owen 1 2, A Ghanim 1, D Elsby 1 3, D J Manton 1 Affiliations + expand PMID: 28881480 DOI: 10.1111/adj.12567 **Free article** ### Abstract **Background:** Dental caries and enamel defects (DDE) are prevalent amongst children. The presence of DDE, especially enamel hypomineralization, may increase caries experience. The reported prevalence of hypomineralized second primary molars (HSPM) is 2.7–21.8%, although the occurrence in Australian children remains unknown. These HSPM represent a potential predictive factor for molar-incisor hypomineralization (MIH). **Methods:** In total, 623 children aged 3–5 years from 30 randomly selected kindergartens participated. The HSPM were recorded using an index combining the European Academy of Paediatric Dentistry MIH Judgment Criteria and modified DDE Index. Caries was recorded using International Caries Detection and Assessment System criteria. **Results:** In total, 144 HSPM were observed in 88 of the 623 (14.1%) children, a tooth-level prevalence of 5.8%. The prevalence of dentinal carious lesions was 13.2%, and caries prevalence (d2-6 mft > 0) was 36.4%. Cavitated carious lesions affected 30.7% of HSPM. **Conclusions:** The relationship between an increase in HSPM lesion extent and increasing number of HSPM per child was statistically significant. A positive association between HSPM severity and extent at tooth level existed (P < 0.05). There was a positive relationship between the extent of HSPM and carious lesion severity (P < 0.05). In this population, children with HSPM did not have overall greater caries experience. **Keywords:** Australian preschool children; demarcated hypomineralized lesion of enamel; developmental enamel defects; early childhood caries; hypomineralized second primary molars.    #### Hypomineralized Second Primary Molars: Prevalence, Defect Characteristics, and Relationship with Dental Caries in Melbourne Preschool Children **Authors:** M. L. Owen, A. Ghanim, D. Elsby, D. J. Manton **Reference:** Aust Dent J. 2018 Mar;63(1):72-80 | DOI: 10.1111/adj.12567 **Background** Dental caries and developmental defects of enamel (DDE) are common in children. Enamel hypomineralization may increase caries experience. Reported global prevalence of HSPM ranges from 2.7% to 21.8%, but Australian data was previously unknown. HSPM is considered a potential predictive factor for Molar-Incisor Hypomineralization (MIH). **Methods** - **Participants:** 623 children (aged 3–5 years) from 30 randomly selected kindergartens. - **HSPM Recording:** Used an index combining European Academy of Paediatric Dentistry (EAPD) MIH criteria and the modified DDE Index. - **Caries Recording:** International Caries Detection and Assessment System (ICDAS) criteria. **Results** - **Prevalence:** 144 HSPM were observed in 88 children (14.1% child-level prevalence; 5.8% tooth-level prevalence). - **Caries Data:** - Overall caries prevalence (d2-6 mft > 0) was 36.4%. - Dentinal carious lesions prevalence was 13.2%. - Cavitated carious lesions affected 30.7% of the identified HSPM. **Conclusions** - There is a statistically significant relationship between the extent of HSPM lesions and the number of HSPM per child. - A positive association exists between HSPM severity and extent at the tooth level (P < 0.05). - A positive relationship exists between the extent of HSPM and carious lesion severity (P < 0.05). - In this specific population, children with HSPM did not demonstrate a higher overall caries experience compared to those without. Clinical photo showing an occlusal view of a child's upper dental arch. The image displays multiple teeth with visible brown discoloration and pitting on the biting surfaces (occlusal enamel), consistent with carious lesions or hypomineralization as described in the context. Close-up clinical photo of a single tooth exhibiting severe decay. The central portion shows extensive brown necrosis/cavitation surrounded by a white/yellow rim of demarcated hypomineralized enamel, matching the 'Hypomineralized second primary molars' topic. Clinical photo showing an occlusal view of a child's lower dental arch. Similar to the upper arch, several teeth show distinct brown staining and defects on the chewing surfaces, illustrating the prevalence of dental issues discussed in the abstract. **Practical Paediatrics** **Dr Jilen Patel** > **J Dent Res**. 2019 Jan;98(1):77-83. doi: 10.1177/0022034518792870. Epub 2018 Aug 3. **Etiology of Hypomineralized Second Primary Molars: A Prospective Twin Study** M J Silva **1 2**, N M Kilpatrick **1 2**, J M Craig **3 4**, D J Manton **5**, P Leong **2 4**, D Burgner **2 6 7 8**, K J Scurrah **1 9** Affiliations + expand PMID: 30074848 PMCID: **PMC6304715** DOI: 10.1177/0022034518792870 **Free PMC article** **Abstract** The etiology of hypomineralized second primary molars (HSPM) is unclear, but genetic and environmental factors have been proposed. The aim of this study was to investigate the relative contribution of genes and environment to the etiology of HSPM and to identify potential environmental risk factors in a longitudinal twin cohort. Children from twin pregnancies (N = 250) were recruited antenatally, and detailed demographic, health, and phenotypic data were collected at recruitment, 24- and 36-wk gestation, birth, and 18 mo of age. 25-Hydroxyvitamin D was quantified for mothers at 28-wk gestation and infants at birth. Dental examinations were conducted on the twins at 6 y of age to determine the presence, severity, and extent of HSPM per standardized criteria. To investigate associations of environmental risk factors with HSPM, multiple logistic regression models were fitted with generalized estimating equations to adjust for twin correlation. Within- and between-pair analyses were performed for unshared continuous variables: birthweight and birth 25-hydroxyvitamin D. Twin-twin concordance for monozygotic (MZ) and dizygotic (DZ) pairs was calculated and compared after adjusting for identified risk factors. A total of 344 twins underwent the 6-y-old dental assessment; HSPM occurred in 68 (19.8%). After adjusting for potential confounders, vitamin D levels at birth, infantile eczema, dizygosity, in vitro fertilization, socioeconomic position, and maternal smoking beyond the first trimester of pregnancy demonstrated the strongest associations with HSPM. Overall concordance for HSPM was 0.47 (95% CI, 0.32 to 0.62) with weak evidence (P = 0.078) of higher concordance in MZ twins (0.63; 95% CI, 0.38 to 0.89) as compared with DZ twins (0.41; 95% CI, 0.24 to 0.58). After adjusting for known risk factors, there was no evidence (P = 0.172) for an additive genetic influence. These findings suggest that shared and unshared environmental factors, such as maternal smoking later in pregnancy and infantile eczema, are important in the etiology of HSPM.  #### Etiology of Hypomineralized Second Primary Molars: A Prospective Twin Study **Authors:** M. J. Silva, N. M. Kilpatrick, J. M. Craig, D. J. Manton, P. Leong, D. Burgner, K. J. Scurrah **Reference:** J Dent Res. 2019 Jan;98(1):77-83 | DOI: 10.1177/0022034518792870 **Study Objective** To investigate the relative contribution of genetic and environmental factors to the etiology of hypomineralized second primary molars (HSPM) and identify potential risk factors within a longitudinal twin cohort. **Methodology** - **Cohort:** 250 twin pregnancies recruited antenatally. - **Data Collection:** Demographic, health, and phenotypic data collected at recruitment, 24- and 36-weeks gestation, birth, and 18 months. - **Biomarkers:** 25-Hydroxyvitamin D levels measured in mothers (28-weeks gestation) and infants (at birth). - **Assessment:** Dental examinations at age 6 to determine HSPM presence, severity, and extent. - **Analysis:** Multiple logistic regression with generalized estimating equations; within- and between-pair analyses for birthweight and vitamin D; twin-twin concordance for monozygotic (MZ) and dizygotic (DZ) pairs. **Key Findings** - **Prevalence:** 344 twins were assessed; HSPM occurred in 68 children (19.8%). - **Risk Factors:** Strongest associations with HSPM included: - Vitamin D levels at birth - Infantile eczema - Dizygosity - In vitro fertilization (IVF) - Socioeconomic position - Maternal smoking beyond the first trimester - **Genetic vs. Environmental Influence:** - Overall concordance for HSPM was 0.47. - MZ twins showed higher concordance (0.63) than DZ twins (0.41), but evidence was weak (P = 0.078). - After adjusting for risk factors, there was no evidence (P = 0.172) for an additive genetic influence. **Conclusions** Shared and unshared environmental factors, specifically maternal smoking later in pregnancy and infantile eczema, appear to be significant in the etiology of HSPM rather than direct genetic inheritance. Clinical intraoral photograph showing the maxillary arch with multiple second primary molars exhibiting hypomineralization. The teeth display white to yellowish opacities and brown discoloration on the occlusal surfaces, consistent with the condition of Hypomineralized Second Primary Molars (HSPM) discussed in the study abstract. # Are Hypomineralized Primary Molars and Canines Associated with Molar-Incisor Hypomineralization? Maria Jose da Silva Figueiredo Sé¹, Ana Paula Dias Ribeiro², Lourdes Aparecida Martins Dos Santos-Pinto³, Rita de Cassia Loiola Cordeiro³, Renata Nunes Cabral¹, Soraya Coelho Leal⁴ Affiliations + expand PMID: 29335050 ## Abstract **Purpose**: The purpose of this study was to evaluate the prevalence of and relationship between hypomineralized second primary molars (HSPM) and hypomineralized primary canines (HPC) with molar-incisor hypomineralization (MIH) in 1,963 schoolchildren. **Methods**: The European Academy of Paediatric Dentisty (EAPD) criterion was used for scoring HSPM/HPC and MIH. Only children with four permanent first molars and eight incisors were considered in calculating MIH prevalence (n equals 858); for HSPM/HPC prevalence, only children with four primary second molars (n equals 1,590) and four primary canines (<small>n</small>/</small> equals 1,442) were considered. To evaluate the relationship between MIH/HSPM, only children meeting both criteria cited were considered (n equals 534); chi-square test between MIH/HPC (n equals 408) and HSPM/HPC (<small>n</small> equals 360); chi-square test and logistic regression. 46% (12.0) percent (9.6); chi-square test and logistic regression (P<0.001). The odds ratio for MIH based on HSPM was 6.31 (95 percent confidence interval [CI] equals 2.59 to 15.13) and for HPC was 6.02 (95 percent CI equals 1.08 to 33.05). **Results**: The prevalence of MIH was 14.69 percent (126 of 858 children). For HSPM and HPC, the prevalence was 6.48 percent (103 of 1,592) and 2.22 percent (32 of 1,442), respectively. A significant relationship was observed between MIH and both HSPM/HPC (P<0.001). The odds ratio for MIH based on HSPM was 6.31 (95 percent confidence interval [CI] equals 2.59 to 15.13) and for HPC was 6.02 (95 percent CI equals 1.08 to 33.05). **Conclusion**: The results led to the conclusion that both hypomineralized second primary molars and hypomineralized primary canines are associated with molar-incisor hypomineralization, because children with HSPM/HPC are six times more likely to develop MIH.  Clinical photograph showing the upper and lower dental arches of a patient. The image displays multiple teeth with visible signs of hypomineralization, characterized by opacities and discoloration on the occlusal surfaces of the molars. **Practical Paediatrics** Dr Jilen Patel **Are Hypomineralized Primary Molars and Canines Associated with Molar–Incisor Hypomineralization?** Maria Jose da Silva Figueiredo Sé 1, Ana Paula Dias Ribeiro 2, Lourdes Aparecida Martins Dos Santos-Pinto 3, Rita de Cassia Loiola Cordeiro 3, Renata Nunes Cabral 1, Soraya Coelho Leal 4 Affiliations + expand PMID: 29335050 **Abstract** **Purpose:** The purpose of this study was to evaluate the prevalence of and relationship between hypomineralized second primary molars (HSPM) and hypomineralized primary canines (HPC) with molar-incisor hypomineralization (MIH) in 1,963 schoolchildren. **Methods:** The European Academy of Paediatric Dentistry (EAPD) criterion was used for scoring HSPM/HPC and MIH. Only children with four permanent first molars and eight incisors were considered in calculating MIH prevalence (n equals 858); for HSPM/HPC prevalence, only children with four primary second molars (n equals 1,590) and four primary canines (<small>n</small>=<small>1</small>,<small>4</small><small>4</small><small>2</small>) were considered. To evaluate the relationship between MIH/HSPM, only children meeting both criteria cited were considered (n equals 534), as was true of MIH/HPC (n equals 408) and HSPM/HPC (<small>n</small>=<small>3</small><small>6</small><small>0</small>); chi-square test and logistic regression. **Results:** The prevalence of MIH was 14.69 percent (126 of 858 children). For HSPM and HPC, the prevalence was 6.48 percent (103 of 1,592) and 2.22 percent (32 of 1,442), respectively. A significant relationship was observed between MIH and both HSPM/HPC (P<0.001). The odds ratio for MIH based on HSPM was 6.31 (95 percent confidence interval [CI] equals 2.59 to 15.13) and for HPC was 6.02 (95 percent CI equals 1.08 to 33.05). **Conclusion:** The results led to the conclusion that both hypomineralized second primary molars and hypomineralized primary canines are associated with molar-incisor hypomineralization, because children with HSPM/HPC are six times more likely to develop MIH.   Clinical intraoral photograph showing the maxillary arch. The image displays significant dental pathology: a large, dark brown cavity on the upper left primary molar and an orange-colored lesion (likely caries or restoration) on the upper right primary molar. Blue arrows point to specific areas of interest on the teeth. Clinical intraoral photograph showing the mandibular arch. Similar to the top image, this view shows an orange-colored lesion on the lower left primary molar and a dark brown cavity on the lower right primary canine/molar area. **Practical Paediatrics** Dr Jilen Patel **Hypomineralized second primary molars:** **prevalence, defect characteristics and relationship with dental caries in Melbourne preschool children** **M L Owen** **1 2** , **A Ghanim** **1** , **D Elsby** **1 3** , **D J Manton** **1** Affiliations + expand PMID: 28881480 **DOI: 10.1111/adj.12567** **Free article** **Abstract** **Background**: Dental caries and enamel defects (DDE) are prevalent amongst children. The presence of DDE, especially enamel hypomineralization, may increase caries experience. The reported prevalence of hypomineralized second primary molars (HSPM) is 2.7-21.8%, although the occurrence in Australian children remains unknown. These HSPM represent a potential predictive factor for molar-incisor hypomineralization (MIH). **Methods**: In total, 623 children aged 3-5 years from 30 randomly selected kindergartens participated. The HSPM were recorded using an index combining the European Academy of Paediatric Dentistry MIH Judgment Criteria and modified DDE Index. Caries was recorded using International Caries Detection and Assessment System criteria. **Results**: In total, 144 HSPM were observed in 88 of the 623 (14.1%) children, a tooth-level prevalence of 5.8%. The prevalence of dentinal carious lesions was 13.2%, and caries prevalence **(d2-6 mft > 0)** was 36.4%. Cavitated carious lesions affected 30.7% of HSPM. **Conclusions**: The relationship between an increase in HSPM lesion extent and increasing number of HSPM per child was statistically significant. A positive association between HSPM severity and extent at tooth level existed (P < 0.05). There was a positive relationship between the extent of HSPM and carious lesion severity (P < 0.05). In this population, children with HSPM did not have overall greater caries experience. **Keywords**: Australian preschool children; demarcated hypomineralized lesion of enamel; developmental enamel defects; early childhood caries; hypomineralized second primary molars.   Clinical intraoral photograph showing the occlusal view of a child's upper dental arch. Two second primary molars are highlighted with red circles to demonstrate hypomineralized lesions and dental caries. Clinical intraoral photograph showing the occlusal view of a child's lower dental arch. Two second primary molars are highlighted with red circles to demonstrate hypomineralized lesions and dental caries. 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