Prevalence of hypomineralised second primary molars (HSPM): A systematic review and meta-analysis

Influence of Vitamin D on Developmental Defects of Enamel (DDE) in Children and Adolescents: A Systematic Review

Background/Objectives: This systematic review aims to investigate the potential association between vitamin D levels and the occurrence of developmental enamel defects (DDE) in children, including conditions like molar-incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPMs). DDEs, which occur during tooth development, can result in significant aesthetic and functional issues, and their exact etiology remains unclear, with both genetic and environmental factors contributing. Among environmental factors, vitamin D deficiency has been proposed as a possible risk factor, given its role in enamel mineralization. Methods: A thorough literature search was conducted in PubMed, Scopus, and Embase. The search strategy included terms such as "vitamin D", "vitamin D deficiency", "developmental defects of enamel", "enamel hypoplasia", "molar-incisor hypomineralization", and "hypomineralized second primary molars". Studies were included if they were original human observational research (cohort, case-control, or cross-sectional) conducted in children under 18 years of age or involving maternal-child cohorts. Ten studies were included in the analysis, with a total of 15,891 participants. The primary data extracted from the selected studies included the following: study design, participants' age, sample size, vitamin D status in relation to developmental defects of enamel, and statistical significance Results: The findings were mixed, with only a few studies suggesting a significant association between low vitamin D levels and the presence of DDEs. Specifically, one study found a link between insufficient maternal vitamin D levels during pregnancy and an increased number of teeth affected by MIH in children. However, the majority of the studies did not report a significant association. Conclusions: This review concludes that while there is some evidence to suggest a possible relationship between vitamin D and DDEs, more research is needed to confirm these findings and better understand the underlying mechanisms.

Prevalence, clinical presentation and risk factors of molar incisor hypomineralisation and hypomineralised second primary molars among children in Buraydah, Saudi Arabia: A cross-sectional study

Background

Molar Incisor Hypomineralisation (MIH) and Hypomineralised second primary molars (HSPM) are qualitative defects of enamel of systemic origin. The objectives of this study were to investigate the prevalence and clinical presentation of MIH and HSPM among Saudi primary school children in Buraydah, Saudi Arabia, to investigate the association between MIH and HSPM, and to assess the association between MIH and HSPM with possible risk factors.

Design and Methods

This was a descriptive cross-sectional study involving 325 primary school children in Buraydah, Saudi Arabia. Data was collected via questionnaire and clinical examination that was conducted by two calibrated examiners, according to the criteria of the European Academy of Paediatric Dentistry (EAPD). Descriptive statistics, Chi-square tests/Fisher's exact tests and odds ratio were used; the significance level was set at p-value ≤ 0.05.

Results

The prevalence values of MIH and HSPM were 18.5% and 11.4%, respectively. There was a significant association between MIH and HSPM (OR = 8.38, 95% CI = 4.027-17.437, p < 0.05). Demarcated opacity (78.5%) was the most common clinical pattern in MIH affected teeth; atypical caries (42.4%) was the most common in cases with HSPM. MIH was significantly associated with otitis media during the first 4 years of life (OR = 3.552, 95% CI = 1.362-9.262, p < 0.05).

Conclusions

MIH and HSPM are common conditions amongst Saudi children (18.5% and 11.4% respectively). HSPM is a risk factor for MIH. Otitis media is associated with MIH. Further research on the aetiology of these conditions is needed.

Frequencies of enamel hypomineralisation in permanent and primary molars in a medieval and early-modern-age population (7th - 17th c.) in Sains-en-Gohelle (Pas de Calais, France)

Molar Incisor Hypomineralisation (MIH) is defined as a qualitative demarcated enamel hypomineralisation defect of tooth enamel affecting at least one first permanent molar (FPM), often affecting permanent incisors. More recently, the term Hypomineralised Second Primary Molar (HSPM) was used to describe similar defects affecting second primary molars. Our observational study aimed at determining HSPM and MIH frequencies in a medieval and early-modern-age population population (Sains-en-Gohelle, France, 7th - 17th centuries) and compare it to the current worldwide and French prevalence values. To date, there are no other studies on this subject in France. European studies have been published, but the diagnosis of these pathologies is based solely on a visual examination. Our study differs from others by using objective diagnostic. microtomography and X-ray fluorescence. The use of these diagnostic methods allows differentiation between hypomineralised and taphonomic lesions. The frequencies of MIH and HSPM were, respectively, 12.3% and 13.3%. In fact, there were 10 individuals with at least one first permanent molar affected by MIH amongst the 81 individuals with at least one first permanent molar present, and 15 individuals with at least one second primary molar affected by HSPM among the 113 individuals with at least one second primary molar present.The presence of MIH and HSPM in ancient populations with frequencies respectively equivalent and higher than current worldwide averages renews the debate and questioning about the aetiological factors of these pathologies.

K, Ramakrishnan M, Jh SF, Prasad M, I. J, Subramani S. Differential Expression of Hard Tissue Proteins in Hypomineralized Second Primary Molars in Comparison to Normal Teeth

OBJECTIVE

This study aims to identify the proteins in hypomineralized second primary molars (HSPMs) and correlate their function in Amelogenesis. HSPM is a qualitative defect of the enamel of the second primary molars with no clear etiology.

MATERIAL AND METHODS

Total protein quantification was performed using the Bradford Protein Assay, followed by the electrophoretic separation of samples using 2D-Gel electrophoresis to identify the proteins.

RESULTS

The results from the Bradford Protein Assay unveiled a five-fold increase in the protein content in HSPM. Proteins such as Dentin sialo-phosphoprotein (DSPP), Keratin, type I, Serum Albumin, Anti-thrombin III, Alpha-1-Antitrypsin, Histone H3.2, Actin, Heat shock Protein, Vimentin, Desmoglein-3, Glyceraldehyde-3-phosphate dehydrogenase, Inosine-5'-monophosphate dehydrogenase 2, Zinc Alpha 2 glycoprotein, Lysozyme C, Prothrombin, Vit-D binding Protein, Apolipoprotein A-1, Defensin 1, Immunoglobulin Gamma, Immunoglobulin Kappa, and Alpha-Amylase were all upregulated (p < 0.05) in HSPM.

CONCLUSION

This investigation conclusively demonstrates that HSPM-affected teeth have higher protein content than healthy teeth. The study also supports the theory of proteolytic inhibition attributed to reduced protease activity and heightened protease inhibitor activity.

Dentists' Knowledge, Attitudes, and Practices Regarding Molar Incisor Hypomineralization (MIH): A French Survey

INTRODUCTION

With an estimated 878 million cases worldwide in 2015, molar incisor hypomineralization (MIH) is a growing issue. Early detection and management require knowledge and application of good clinical practices. The aim of the study was to evaluate the knowledge, attitudes, and practices of French dentists regarding MIH.

METHOD

A self-administered questionnaire was distributed to different groups of practitioners between 30 January and 27 March 2023, including members of the French dental practice-based research network, members of the social network "French pediatric dentists," and members of the professional social network LinkedIn (LinkedIn, Sunnyvale, California, United States). The data from 311 questionnaires were analyzed.

RESULTS

Around 277 (89%) practitioners were familiar with MIH, 180 (58%) were perfectly aware of the clinical features of MIH, and 193 (62%) reported being able to clinically identify MIH. Nearly 100% (310) of dentists cited "environmental pollutants" as the most frequent etiological factor. Glass ionomer is the most used restorative material.

CONCLUSION

Education regarding MIH must be improved among dentists to correctly detect, treat, or refer patients. It would seem useful to carry out an MIH prevalence study in France.

Knowledge and management of molar-incisor hypomineralisation amongst dentists in The Netherlands

BACKGROUND

Molar-incisor hypomineralisation (MIH) is a frequently encountered dental condition in the clinical setting, and correct diagnosis can influence management outcomes.

AIM

To assess the knowledge of and attitudes towards the management of MIH amongst dentists in the Netherlands.

DESIGN

The study was conducted as a cross-sectional web survey. The questionnaire used included questions regarding respondent characteristics, awareness, knowledge and management of MIH and was distributed through the Royal Dutch Association for Dentistry (KNMT) to a random sample of 900 dentists. Variables were analysed using descriptive statistics, and differences between distinct groups of dentists were tested using the chi-squared test.

RESULTS

Respondents consisted of 76.6% general dental practitioners, 9.1% paediatric dentists and 14.3% differentiated (specialist) dentists, with a 25.6% overall response rate. The majority knew the term MIH and its clinical characteristics, and could distinguish MIH from other enamel defects. Regarding aetiological factors, 76.6% reported a genetic component. In an asymptomatic case, 47.3% reported non-invasive treatments. In a mild symptomatic case, treatments from non-invasive to invasive were reported (p < .05). In a severe symptomatic case, the majority reported invasive treatments. Two-thirds of respondents were interested in further clinical training about MIH.

CONCLUSIONS

Most respondents knew the term MIH and its clinical characteristics and would like further clinical training about MIH.

Pretreatments to bonding on enamel and dentin disorders: a systematic review

INTRODUCTION

This systematic review focuses on structural anomalies of enamel and dentin such as fluorosis (F), molar-incisor hypomineralization (MIH), amelogenesis imperfecta (AI), dentinogenesis imperfecta (DI), osteogenesis imperfecta (OI), and X-linked hypophosphatemia (XLH). These pathologies affect up to 31% of the population, posing challenges in the adhesion of direct restorations. The primary objective of this analysis is to examine the survival rate and/or bonding resistance of direct restorations on tissues affected by enamel and dentin disorders in humans. We aim to provide precise clinical recommendations for dentists to choose the appropriate bonding pretreatment for various enamel and dentin disorders.

METHODS

We systematically searched the medical literature to identify abstracts of interest indexed between 1993 and May 2024, from 4 databases (PubMed, PMC-PubMed, Web of Science and Cochrane Library). The results are reported following the PRISMA statement. The GRADE approach was used to assess the risk of bias.

RESULTS

The two authors included 27 studies out of the 600 identified. The data extracted from these studies are highly heterogeneous, and the mentioned bonding protocols are all different. 15 articles pertain to F, 7 to MIH, 5 to AI, and none focus on HSPM, dentin disorders and XLH. We identified 12 pretreatments of enamel or dentin (7 for F, 2 for MIH, and 3 for AI), including 3 strong recommendations. Additional studies are necessary to confirm the effectiveness of certain pretreatments. In developmental enamel defects, the main recommendation we collected is to bond on enamel with an etch-and-rinse technique on F and MIH. Considerations with lower strength of evidence include a deproteinization step on enamel on F, MIH and AI and modifications of the etching parameters on F and AI. The research strategy was registered on the Prospero platform (CRD42023447502).

Prevalence of hypomineralized second primary molars and association with socioeconomic characteristics and dental caries in a Brazilian population of preschoolers: a cross-sectional study

OBJECTIVE

To analyze the prevalence of hypomineralized second primary molar (HSPM) and its association with socioeconomic characteristics and dental caries in a Brazilian population of preschoolers.

MATERIAL AND METHODS

603 preschoolers, enrolled in public preschools in Itajaí (state of Santa Catarina, Brazil), took part in the study. To assess the participants' socio-economic characteristics, an original questionnaire was formulated and sent to the children's parents. The clinical evaluation was carried out by a calibrated examiner using the deft/DMFT index for dental caries and Ghanim et al. (Ghanim et al., Eur Arch Paediatr Dent, 2015) criteria for HSPM. The data were analyzed through Poisson regression, using STATA statistical software, and the association analyses were presented by prevalence ratios (PR).

RESULTS

The prevalence of at least one HSPM-affected second molar was 24.5%. The prevalence of HSPM was associated to the city's geographical regions of the Educational hubs (p < 0.001). A significant association was found between dental caries and HSPM (p = 0.003; PR: 1.31; 95% CI 1.09-1.56). Children with HSPM were 31% more likely to experience dental caries than children without HSPM. Geographical regions of educational hubs were also significantly associated with HSPM (p < 0.001). None of the socioeconomic characteristics was associated with HSPM (p > 0.05).

CONCLUSION

HSPM is a common developmental defect of enamel in children in our study. The HSPM distribution was associated with the city's geographic regions. Children with HSPM are more likely to experience dental caries. Socioeconomic characteristics were not associated with HSPM.

Prevalence and Association of Caries and Enamel Hypomineralisation/Molar-Incisor Hypomineralisation in 8- to 10-Year-Old Children from Bavaria, Germany

INTRODUCTION

The aim of this cross-sectional epidemiological study was to record caries and enamel hypomineralisation (EH), including molar-incisor hypomineralisation (MIH), and assess associations between both entities in 8- to 10-year-olds from Bavaria, Germany.

METHODS

A total of 5,418 children (mean age 9.8 years; 2,726 females, 2,692 males) were examined using the dmft/DMFT index with additional inclusion of initial or non-cavitated carious lesions (it/IT). EHs were recorded in the primary (eh) and permanent dentition (EH), and individuals with different EH phenotypes were determined as follows: at least one EH, at least one hypomineralised second primary molar (HSPM), at least one hypomineralised first permanent molar (MIH), and at least one hypomineralised first permanent molar and incisor (M+IH). Multiple logistic regression models were constructed to assess association between caries and EH.

RESULTS

The percentage of children without caries in the permanent dentition (DMF = 0) was 88.9%. When data regarding initial carious lesions were included (IDMF = 0), the prevalence decreased to 75.7%. The caries experience was idmf/t = 1.6 and the IDMF/T = 0.6. The mean number of carious teeth in subjects with no eh/EH was higher than that in subjects with HSPM, MIH, or M+IH. The presence of HSPM, MIH, and M+IH was associated with a significantly lower probability of caries in the permanent dentition; the corresponding adjusted odds ratios were 0.55 (95% CI: 0.41-0.75), 0.67 (95% CI: 0.56-0.81), and 0.54 (95% CI: 0.41-0.72), respectively.

CONCLUSIONS

Caries and EH are prevalent conditions in 8- to 10-year-old Bavarian schoolchildren; both dental diseases were negatively associated with each other.

Awareness of Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPMs) among Northern Italian Dentists: A Questionnaire Survey

BACKGROUND

The purpose of this study was to assess the awareness of molar incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPMs) among dental practitioners in Northern Italy, and to gather data on the occurrence of these conditions in their paediatric patients.

METHODS

A cross-sectional study was conducted using a structured online questionnaire administered through Google Forms. The survey comprised 10 single-choice questions addressing the occurrence of MIH and HSPM in caries-free patients aged 6-9 years.

RESULTS

A total of 315 dentists participated in the survey, yielding a response rate of 31.5%. The majority of respondents reported that 1-25% of their paediatric patients exhibited HSPMs. Among this group, 43.62% of respondents observed MIH in 1-25% of cases.

CONCLUSION

The findings from this survey suggest a consistent perception of MIH and HSPMs among dental practitioners, aligning with known prevalence data and indicating recognition of these conditions within the dental community in Northern Italy.

Hypomineralised second primary molars: the Würzburg concept

PURPOSE

In addition to molar incisor hypomineralisation, the occurrence of enamel hypomineralisation in the primary dentition has become increasingly important in recent years. Hypomineralised second primary molar (HSPM) is defined as hypomineralisation of systemic origin affecting from one to all four second primary molars. Some years ago, the "Würzburg concept" was introduced, which proposed a grading of MIH findings (MIH treatment need index) in combination with an appropriate treatment plan depending on the severity of the affected tooth. Recently, this concept was updated and new treatment approaches have been added. However, currently, the concept solely addresses the treatment plan for permanent teeth. As there is a need to expand its scope to encompass primary teeth and, consequently, HSPM, this paper seeks to develop the second component of the Würzburg concept, the treatment plan, for the primary dentition in response to the increased focus on the disease in recent years. Although the evidence base for the different treatment options is still weak, there is a need for guidance for clinicians in their day-to-day practice.

METHODS

The authors conducted a comprehensive review of the literature, encompassing clinical and laboratory studies along with published guidelines.

RESULTS

The treatment plan of the HSPM Würzburg concept contains prophylactic and regenerative aspects, non-invasive interventions, temporary and permanent restorative techniques, and extraction.

CONCLUSIONS

The intention is to provide practical guidance to practitioners, acknowledging the necessity for further validation through clinical trials.

Molar-Incisor Hypomineralisation: Severity, caries and hypersensitivity

OBJECTIVES

To investigate distribution of affected teeth and severity of molar-incisor hypomineralisation (MIH) in 8-9-year-old children. A second aim was to study association between severity of MIH and hypersensitivity, caries, and affection of incisors and second primary molars (SPM).

METHODS

A total of 3013 children in one age cohort participated in a cross-sectional study, of which 851 children were diagnosed with MIH. A majority of these children were re-examined and MIH diagnosis based on the European Academy of Paediatric Dentistry criteria was confirmed in 538 children. The re-examinations were undertaken at the local clinics by one calibrated dentist. Data were tested with bivariate logistic regression analysis. Results were reported using frequencies, proportions, odds ratios (OR) and confidence intervals (CI).

RESULTS

Almost half of the children with MIH (46.8 %) had at least one severely affected molar. Incisors were affected in 51.9 % of children with MIH, and the prevalence was higher in children with severe affection (57.4 %, p < 0.01). Among children with MIH, second primary molars were affected in 29.6 %, hypersensitivity in at least one first permanent molar was reported by 25.8 and 30.8 % had caries extending to dentine. Children classified with severe MIH were more likely to suffer from hypersensitivity (OR 5.62, 95 % CI 3.61-8.74) and dentine caries (OR 10.32, 95 % CI 6.46-16.50) than children with mild MIH.

CONCLUSION

Prevalence of hypomineralised incisors and SPM were high in the studied children with MIH. Children with severe MIH had higher probability of incisor affection, dentin caries and hypersensitivity.

CLINICAL SIGNIFICANCE

This study highlights the importance of understanding the association between MIH, caries and hypersensitivity, especially in children with severe MIH. These children need extensive and individualized care in the dental services to prevent caries and pain.

Household smoking impact on the oral health of 5- to 7-years-old children

BACKGROUND

Children's exposure to secondhand smoke, particularly by their parents, could adversely affect their oral health. Thereby, this study aimed to assess the oral health status of children subjected to household smoking and the impact of smoking patterns on the severity of oral health deterioration.

METHODS

A total of 210 healthy children were enrolled in this case-control study and allocated into children subjected to household smoking (HS) and control groups. Participants' guardians were asked to complete a questionnaire regarding sociodemographic characteristics and parental smoking habits. All participants were subjected to clinical dental examination to assess dental caries (ICDAS), hypomineralized primary molars (HSPM), and gingival status (GI). Stimulated saliva samples were collected to assess saliva composition and characteristics. Urine samples were collected and analyzed for cotinine concentration. Data were analyzed using SPSS (v.25) software at a test value of p ≤ 0.05. The t-student test was used to find significant differences between participants' age, gingival index score, saliva pH, flow rate, sIgA, and cotinine level. The Chi-square test was used to test for the significance of parental employment, number of rooms, gender, sweets consumption, brushing frequency, and HMPM. The correspondence analysis was used to test for significance of parents' levels of education, type of house ventilation, ICDAS score, smoking form, frequency, and smoking pattern. The correlation between cotinine level and sIgA was tested for association using Bivariate correlation test.

RESULTS

The HS group showed a significantly increased risk for dental caries (p < 0.000), HSPM lesions (p = 0.007), and GI score (p < 0.000). A significant reduction in salivary flow rate, saliva pH, and sIgA were evident in HS group (p < 0.000). Parental consumption of more than 20 cigarettes/day was accompanied by increased dental caries activity (p < 0.000) and higher risk for increased severity of gingival inflammation (p < 0.000) of children in the HS group. Children of parents who smoke cigarettes and use the hubble/bubble anywhere in the house found to have greater distribution of HSPM (p < 0.000). Reduced sIgA values were found to be significantly associated with increased cotinine concentrations in HS children (p < 0.000).

CONCLUSIONS

Frequent exposure to household smoking could be associated with an increased risk of dental caries progression, enamel hypomineralization, gingival inflammation, and saliva characteristics changes in children.

General dentists' perceptions and clinical management of hypomineralised second primary molars (HSPM) in Ireland

PURPOSE

This questionnaire aimed to explore how general dentists in the Republic of Ireland perceive and manage hypomineralised second primary molars (HSPM).

METHODS

Following ethical approval, a validated structured questionnaire containing 19 questions was sent to Irish dentists using Survey Monkey. Questions on awareness, dentist's experience, barriers to care and clinical scenarios with different treatment options were included. Binary outcomes and independent variables were compared using logistic regression analysis (α = 5%).

RESULTS

Responses from 279 general dentists were analysed. The majority of dentists were aware of HSPM (72%) and most dentists felt confident in diagnosing HSPM (71%). Dentists who had practiced for ≥ 15 years were significantly more likely to document HSPM frequently compared to those with less experience (OR 0.29; p = 0.012). No significant association was found between confidence in HSPM diagnosis and other variables, such as age group, years of practice and workplace. Dentists not working in private practice reported to be less comfortable in the management of HSPM (OR 0.49; p = 0.030). The most cited barrier to management of HSPM was child's behaviour. A broad variation was observed in the clinical scenarios, in particular when treatment planning more severe HSPM.

CONCLUSIONS

In general, Irish dentists are aware of HSPM and are confident in diagnosis and management. Variation existed in treatment options reflecting the disparity that exists in clinical management.

Autoimmune amelogenesis imperfecta in patients with APS-1 and coeliac disease

Ameloblasts are specialized epithelial cells in the jaw that have an indispensable role in tooth enamel formation-amelogenesis1. Amelogenesis depends on multiple ameloblast-derived proteins that function as a scaffold for hydroxyapatite crystals. The loss of function of ameloblast-derived proteins results in a group of rare congenital disorders called amelogenesis imperfecta2. Defects in enamel formation are also found in patients with autoimmune polyglandular syndrome type-1 (APS-1), caused by AIRE deficiency3,4, and in patients diagnosed with coeliac disease5-7. However, the underlying mechanisms remain unclear. Here we show that the vast majority of patients with APS-1 and coeliac disease develop autoantibodies (mostly of the IgA isotype) against ameloblast-specific proteins, the expression of which is induced by AIRE in the thymus. This in turn results in a breakdown of central tolerance, and subsequent generation of corresponding autoantibodies that interfere with enamel formation. However, in coeliac disease, the generation of such autoantibodies seems to be driven by a breakdown of peripheral tolerance to intestinal antigens that are also expressed in enamel tissue. Both conditions are examples of a previously unidentified type of IgA-dependent autoimmune disorder that we collectively name autoimmune amelogenesis imperfecta.

Predictive Value of Hypomineralization of Second Primary Molars for Molar Incisor Hypomineralization and Other Relationships between Both Developmental Defects of Dental Enamel

Molar incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPM) are dental enamel developmental defects with significant prevalence and psychophysical impact, posing a public health concern. We examined the relationship between HSPM and MIH in 426 children aged 7 to 10 years (213 with MIH, 213 without MIH). The frequency of HSPM was higher in children with MIH (37.1% vs. 11.3%, p < 0.001). However, there was no correlation between MIH severity and presence of HSPM (p = 0.296). In patients with both defects (n = 79), 90% of severe MIH cases were associated with severe HSPM, while 87.8% of mild MIH cases were associated with mild HSPM (p < 0.001). The involvement of permanent incisors by MIH was not influenced by the presence of HSPM or HSPM severity. HSPM exhibited a positive predictive value of 76.7, negative predictive value of 58.8, sensitivity of 37.1% (95% CI = 30.6-43.6%), and specificity of 88.7% (95% CI = 84.5-93%). The odds ratio for MIH based on HSPM was 4.64 (95% CI). HSPM may serve as a predictor of MIH, but its absence does not rule out the occurrence of MIH. The results highlight the need for surveillance programs in children presenting with HSPM to facilitate early diagnosis and preventive measures for MIH-related complications.

Association between genetic factors and molar-incisor hypomineralisation or hypomineralised second primary molar: A systematic review

OBJECTIVE

To determine the association between genetic factors and molar-incisor hypomineralisation (MIH) and/or hypomineralised second primary molars by means of a systematic review.

DESIGN

A search was performed in Medline-PubMed, Scopus, Embase and Web of Science databases; manual search and search in gray literature were also performed. Selection of articles was performed independently by two researchers. A third examiner was involved in cases of disagreement. Data extraction was performed using an Excel® spreadsheet and independent analysis was performed for each outcome.

RESULTS

Sixteen studies were included. There was an association between MIH and genetic variants related to amelogenesis, immune response, xenobiotic detoxification and other genes. Moreover, interactions between amelogenesis and immune response genes, and SNPs in the aquaporin gene and vitamin D receptors were associated with MIH. Greater agreement of MIH was found in pairs of monozygotic twins than dizygotic twins. The heritability of MIH was 20 %. Hypomineralised second primary molars was associated with SNPs in the hypoxia-related HIF-1 gene and methylation in genes related to amelogenesis.

CONCLUSION

With very low or low certainty of evidence, an association was observed between MIH and SNPs in genes associated with amelogenesis, immune response, xenobiotic detox and ion transport. Interactions between genes related to amelogenesis and immune response as well as aquaporin genes were associated to MIH. With very low certainty of evidence, hypomineralised second primary molars was associated to a hypoxia-related gene and to methylation in genes related to amelogenesis. Moreover, higher agreement of MIH in pairs of monozygotic twins than dizygotic twins was observed.

Dental enamel defects and dental caries of primary teeth among Indigenous children in Western Australia

BACKGROUND

Teeth affected with enamel defects (EDs) are at an increased risk of dental caries. In spite of improving oral health status overall in Australia, Indigenous Australians still experience higher rates of dental caries than non-Indigenous Australians. This study reports on the prevalence of EDs and dental caries experience among Indigenous children in the Kimberley region of Western Australia.

METHODS

Health status of all the primary teeth (ICDAS II criteria) and the presence of EDs on index teeth (modified Dental Defects of Enamel index; DDE) of young Indigenous children who participated in a 2-arm intervention trial was recorded. Generalized estimating equations were used to estimate the association between EDs and dental caries and effect estimates were presented as odds ratios and associated 95% confidence intervals.

RESULTS

Person-level prevalence, from 237 children (mean age 3.6 years, standard deviation 1.7) assessed for EDs, was 58% and tooth-level prevalence was 24%. Teeth affected with demarcated or diffuse defects were associated with a twofold higher odds of having caries experience, odds ratio (OR) 2.5, 95% confidence interval (CI) 1.7-3.7 and OR 2.7, 95% CI 1.7-4.0 respectively.

CONCLUSIONS

The presence of EDs among young Indigenous children was associated with a higher odds of caries experience among affected teeth.

The prevalence and characteristics of and the association between MIH and HSPM in South-Western France

BACKGROUND

Molar-incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPM) involve qualitative structural developmental anomalies of tooth enamel, affecting the first permanent molars (FPM) and the second primary molars, respectively. This developmental anomaly of systemic origin has important consequences for oral health.

AIM

To determine the prevalence of MIH and HSPM in south-western France and explore the distribution of hypomineralised lesions on permanent and primary molars.

DESIGN

Amongst 856 children (aged 7-9 years) in schools randomly selected by the Academy of Bordeaux (Ministry of Education), the FPM, permanent incisors and the second primary molars were examined by two examiners trained and calibrated for the diagnostic criteria for MIH and HSPM of the European Academy of Paediatric Dentistry.

RESULTS

Molar-incisor hypomineralisation was present in 160 children (18.7%) and HSPM in 81 children (9.5%); 4.9% had both HSPM and MIH (42 of 856). Hypomineralised lesions were present in 1-4 FPM in affected individuals (mean = 2.4) and were distributed in an asymmetrical manner with widely varying severity at the tooth and individual level. A child with HSPM was more likely to have MIH than a child without HSPM (95% CI OR = 6.0 [3.7-9.7]; p < .0001).

CONCLUSION

Molar-incisor hypomineralisation and HSPM have three main asymmetrical characteristics: tooth location, severity of hypomineralisation and number of teeth affected.