On the Etiology of Molar-Incisor Hypomineralization

Molar-incisor hypomineralization in a cohort of individuals born with cleft lip and palate

OBJECTIVE

This study aimed to investigate the frequency of molar-incisor hypomineralization (MIH) in individuals born with cleft lip and or cleft palate.

SETTINGS AND SAMPLE

Three hundred eighty-six individuals born with cleft lip and/or palate before orthodontic treatment.

METHODS

All the individuals were submitted to a clinical examination and intraoral standardized photos. The registration of MIH was taken by two orthodontists and analysed in association with the cleft type and laterality. The Kruskal-Wallis test and the regression test were used to compare the frequency of molars and incisors affected according to cleft type and laterality, sex and age.

RESULTS

We found a frequency of 67.87% of MIH in the studied sample. The frequency varied from 25% (in individuals born with cleft palate) to 77% in individuals born with bilateral cleft lip and palate). The number of affected molars was statistically different depending on cleft type and laterality (P < .001- Kruskal-Wallis test). Differences were found between individuals born with unilateral cleft lip and palate and unilateral cleft lip and alveolus (P = .03), and with isolated cleft palate (P = .03), and between individuals born with bilateral cleft lip and palate and born with unilateral cleft lip and alveolus (P = .01), and cleft palate (P = .01). Sex (P = .21) and age (P = .36) had no influence on the frequency of MIH. A positive correlation was found between the number of molars affected and incisors affected (P < .001).

CONCLUSION

Individuals born with cleft lip and palate have a higher frequency of MIH, and the complexity of cleft type was associated with the number of affected molars.

Gestational Serum Retinol Deficiency Is Associated with Enamel Hypoplasia

Enamel hypoplasia (EH) is a prevalent developmental defect of teeth that can result from various insults, including prenatal nutrient deficiencies. This study aimed to evaluate the association between prenatal serum retinol deficiency and EH in the deciduous teeth of offspring at 2-y of age. A cohort of 1,450 pregnant women was enrolled, and their prenatal nutritional status was assessed between 12 and 14 wk of gestation. Maternal serum retinol, serum 25-hydroxyvitamin D (25OHD), hemoglobin, body mass index, and birth outcomes, infant feeding practices, family socioeconomic status, and demographic information were recorded. Oral health examinations were conducted for the children semiannually, and EH was diagnosed using the Modified DDE index on all the surfaces of erupted teeth. A modified Poisson regression analysis was used to assess the cumulative risk of EH over a period of 2-y. A total of 920 (63.4%) mother-child pairs completed the study, and the cumulative EH prevalence among offspring after 2-y of follow-up was 16.5% (N = 152; 87/1,114 children in the first year and 132/920 in the second year, with 20/920 having EH only in the first year). After adjusting for potential confounders, maternal serum retinol deficiency significantly increased the risk of deciduous EH (risk ratio [RR], 2.0; 95% confidence interval [CI], 1.1-3.7). In addition, deficient serum 25OHD (RR, 6.5; 95% CI, 4.0-10.7), caesarean delivery (RR, 1.6; 95% CI, 1.0-2.4), Muslim (RR, 2.9; 95% CI, 2.0-4.1) and Christian (RR, 2.4; 95% CI, 1.6-3.5) versus Hindu religions, and very preterm birth (RR, 1.7; 95% CI, 1.1-2.9) increased the risk of EH. Children presenting with EH had 2 or more teeth affected, and the maxillary incisors were the most frequently affected, followed by the first primary molars and canines. In conclusion, maternal serum retinol deficiency during the 12 to 14 wk of gestation may increase the risk of deciduous EH, besides the well-established 25OHD deficiency.

Comparison between two molar incisor hypomineralization detection criteria in epidemiological surveys

BACKGROUND

There is no consensus on which molar incisor hypomineralization (MIH) indices are more suitable for epidemiological surveys.

AIM

To compare the operational aspects and diagnostic ability of the MIH index (simplified/MIH_s and extended/MIH_e) with the MIH-Severity Scoring System (MIH-SSS) in classifying and diagnosing MIH.

DESIGN

This cross-sectional study assessed the indices in a homogeneous group of 680 6- to 10-year-old schoolchildren in Bauru, Brazil, who had at least one first permanent molar, ensuring consistent conditions. Followed by toothbrushing, the children seated on school chairs were examined by the two calibrated researchers under artificial lighting, using mouth mirror and WHO probe, and chronometer recording the duration of examinations.

RESULTS

The prevalence of MIH was 24.7%. The most common characteristic of MIH was demarcated opacity, with a prevalence of 81.7% and 85.45% according to the MIH_s and the MIH-SSS, respectively. A positive association was observed among the MIH_s, the MIH_e, and the MIH-SSS (chi-squared test; p < .01). The MIH-SSS demonstrated a shorter average application time than both versions of the MIH index (ANOVA/Tukey; p < .05). Additionally, fluorosis was found to be the most prevalent among other developmental defects of enamel, with a prevalence of 38.38%.

CONCLUSION

All systems effectively diagnosed MIH and its characteristics.

Prevalence and severity of molar-incisor hypomineralization, is there an association with socioeconomic status? A cross-sectional study in Chilean schoolchildren

PURPOSE

Data about molar-incisor hypomineralization (MIH) prevalence and its severity remains limited for some Latin American countries. Furthermore, its association with socioeconomic status (SES) is still unclear. Thus, this study aims to determine the prevalence and severity of MIH in Santiago, Chile and explore its association with SES.

METHODS

A cross-sectional study with schoolchildren between 6 and 12 years was conducted. Children were evaluated using the European Academy of Paediatric Dentistry to diagnose MIH, and the Mathu-Muju and Wright criteria to determine its severity.

RESULTS

A total of 1,270 children were included. The MIH prevalence was 12.8% without association with gender (p = 0.609). Prevalence was higher among schoolchildren ages 8 and 9 (p = 0.002), and in lower SES (p = 0.007). MIH mild cases were the most prevalent (63%), and severity was not related to gender (p = 0.656), age (p = 0.060), or SES (p = 0.174).

CONCLUSIONS

The prevalence of MIH in the province of Santiago, Chile is 12.8% and was found to have a higher incidence in 8-9-year-old students and among those categorized by low SES. Furthermore, MIH prevalence was associated with low SES.

IMPLICATIONS

Public health policies to address MIH in Chile should start with schoolchildren aged 8 to 9, and with low SES.

Impact of molar incisor hypomineralization on oral health-related quality of life in 8-10 years old children: A systematic review and meta-analysis

OBJECTIVES

This study aimed to evaluate the impact of molar incisor hypomineralization (MIH) and its different severities on various aspects of oral health-related quality of life (OHRQoL) in children between 8 and 10 years of age.

DATA SOURCES

The search terms were chosen according to the Medical Subject Headings (MeSH) and non-MeSH. Potentially eligible studies involved the OHRQoL evaluation in 8-10 years old children with MIH. An electronic search of published studies was carried out in August 2022 on Scopus, Web of Science, and PubMed databases. Of 130 papers retrieved initially, 21 were eligible to be included in the systematic review, of which 8 were excluded. The OHRQoL questionnaires used in the studies included Caregivers Perceptions Questionnaire (CPQ) 8-10, Child Oral Health Impact Profile questionnaire, and Child Oral Impacts on Daily Performances questionnaire. Nine studies using CPQ8-10 contributed to the meta-analysis.

RESULTS

According to meta-analysis, the results revealed that in MIH children a significant increase was observed in the total score of CPQ 810 with the pooled mean of 15.89 (95% confidence interval [CI]:8.95-22.84; P-value = .001) and in oral symptoms, functional limitation and emotional well-being domains with the pooled means of 6.25 (95% CI:4.01-8.50; P-value = .001), 3.88 (95% CI:1.93-5.83; P-value = 0.001), and 3.24 (95% CI:0.96-5.52; P-value = .01), respectively. While the increase in social well-being with the pooled mean of 1.65 (95% CI: -0.47 to 3.76; P-value = .13) was not significant. Subgroup analysis based on MIH severity showed no significant difference in OHRQoL means for all variables.

CONCLUSION

Suffering from MIH, negatively affected the total score and all domains of the CPQ 8-10 questionnaire, except for social well-being. Furthermore, different severities of MIH had no significant impact on OHRQoL in children.

Insights into molar-incisor hypomineralisation in past populations: A call to anthropologists

OBJECTIVE

Molar incisor hypomineralisation (MIH) is a developmental defect of enamel affecting the first permanent molars and often the incisors and affecting approximately 13% of the current population worldwide. Here, we aim to highlight potential differential diagnoses of MIH in archaeological collections (taphonomic discoloration, amelogenesis imperfecta, fluorosis, rachitic teeth, etc.).

METHODS

Causative factors of dental discolourations are identified through a literature review.

RESULTS

In an archaeological context, the sediments contained in the burial soil can lead to tooth discoloration. Taphonomic staining of the dentition may have a similar appearance to enamel hypomineralisation, and thus is a confounding factor that has the potential to cause miscalculation of the true prevalence of MIH within archaeological collections. Some rare medieval cases are reported in the modern literature but without microanalysis, misdiagnosis is possible. The aetiological factors of MIH are unknown but probably follow the multifactorial model involving systemic medical and genetic factors.

CONCLUSIONS

Systematic detection and diagnosis of MIH during anthropological studies is therefore of great interest.

SIGNIFICANCE

The hypotheses that only contemporary agents are causative factors of MIH could be refuted by the discovery of individuals living before medication or pollutants. The identification of MIH in a group of individuals also provides information regarding the health status of a population and reflects stress occurring during the period of mineralisation of the first permanent molars after secretion of the enamel matrix.

LIMITATIONS

Taphonomic alterations of archaeological remains prevent MIH diagnosis.

SUGGESTIONS FOR FUTURE RESEARCH

MIH diagnosis can be difficult in archaeological series and further non-destructive methods (microtomography, elemental analyses, etc.) are required.

Etiological Factors of Molar Incisor Hypomineralization: A Systematic Review and Meta-Analysis

Molar incisor hypomineralization (MIH) is a defect of the dental enamel that predominantly affects first molars and permanent incisors. Identifying the significant risk factors associated with MIH occurrence is essential for the implementation of prevention strategies. The purpose of this systematic review was to determine the etiological factors associated with MIH. A literature search was carried out from six databases until 2022; it covered pre-, peri-, and postnatal etiological factors. The PECOS strategy, PRISMA criteria, and the Newcastle-Ottawa scale were used, and 40 publications were selected for qualitative analysis as well as 25 for meta-analysis. Our results revealed an association between a history of illness during pregnancy (OR 4.03 (95% CI, 1.33-12.16), p = 0.01) and low weight at birth (OR 1.23 (95% CI, 1.10-1.38), p = 0.0005). Furthermore, general illness in childhood (OR 4.06 (95% CI, 2.03-8.11), p = 0.0001), antibiotic use (OR 1.76 (95% CI, 1.31-2.37), p = 0.0002), and high fever during early childhood (OR 1.48 (95% CI, 1.18-1.84), p = 0.0005) were associated with MIH. In conclusion, the etiology of MIH was found to be multifactorial. Children with health disorders in the first years of life and those whose mothers underwent illnesses during pregnancy might be more susceptible to MIH.

Molar-Incisor Hypomineralization: Prevalence Comparative Study in 6 Years of Interval

The aim of this study was to evaluate the prevalence evolution rate of MIH (molar-incisor hypomineralization) after a 6-year period in Araraquara/SP, Brazil. This population-based study evaluated MIH in 545 schoolchildren (6-12 years of age) and other associated alterations, dental caries and dental fluorosis (DF). A semistructured questionnaire was sent to the schoolchildren's parents/guardians with the purpose of identifying the socioeconomic profile. Associations between MIH and the clinical characteristics were analyzed by the Poisson analysis of regression with robust variance, estimating the RPc (crude prevalence ratio) with CI 95%. The level of significance of 5% was adopted. The MIH prevalence in Araraquara/SP in 2016 was 14.3% (n = 78), and at this time, an increase of 2% was observed, in comparison with the data of the first prevalence study conducted in 2010 (12.3%). The mild degree compromise was the most prevalent diagnosis in the affected teeth (82.0%). Among children with MIH, the mean number of affected teeth was 2.78. Of the total number of children with MIH, 32.0% presented alterations in both first permanent molars and permanent incisors. There is no significant association between MIH and dental caries experience on permanent dentition (PRc = 1.141; CI 95% 0.709-1.835) or on primary dentition (PR c  = 1.132; CI 95% 0.749-1.709). Children with MIH presented significantly less prevalence of dental fluorosis (PR c  = 0.505; CI 95% 0.268-0.950). There is no association between MIH and monthly Brazilian minimal wage income (PR c  = 1.130; CI 95% 0.655-1.949). It was concluded that the number of MIH cases had increased, revealing a greater need for defining the etiological factors and establishing a correct diagnosis to make it possible to institute early intervention.

Identification by whole-exome sequencing of new single-nucleotide polymorphisms associated with molar-incisor hypomineralisation among the Lebanese population

OBJECTIVE

Molar-incisor hypomineralization (MIH) is a developmental qualitative enamel defect, causing a worldwide challenging dental problem. The etiology of this defect remains unclear. Here we identify by whole-exome sequencing (WES) new single-nucleotide polymorphisms (SNPs) in genes expressed during enamel mineralization and in those modulating prenatal, natal and postnatal risk factors among the Lebanese MIH children: immune system and xenobiotic detoxification.

DESIGN

Dental examination for MIH was performed based on the MIH index for diagnostic criteria. Saliva samples were collected from 37 non-related, MIH-diagnosed subjects for DNA extraction. WES was performed on the Illumina HiSeq2000 platform. The χ² test and Fisher's exact test were used to determine relationship between SNPs frequencies and MIH. OR and its 95% CI were used to report the strength of association. The significance threshold was set at 0.05.

RESULTS

Among the Lebanese population, 37 SNPs presented a significant association with MIH in the following genes: AMTN, MMP-20, STIM1, STIM2, ORAI1, SLC34A2, SLC34A3, VDR, PVALB, HSP90B1, TRPM7, SLC24A4, CA6, SLC4A2, TNFRSF11A, IL10RB, ARNT, ESR1 and CYP1B1.

CONCLUSION

This is the first WES study conducted in patients with MIH. Yet, interactions between polymorphisms in different gene categories are to be investigated for a better assessment of MIH susceptibility.

Are Molar-Incisor Hypomineralization and Hypomineralized Second Primary Molars Predictive of Dental Caries?: A Systematic Review

To estimate the prevalence of dental caries among children affected concomitantly with molar-incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPM).Electronic databases, including Medline via PubMed, Cochrane Library, Scopus, and Science Direct, were searched. Studies written in English involving children with MIH-HSPM and dental caries were considered eligible. Two reviewers extracted the data according to the PRISMA statement and assessed the bias risk with the Newcastle-Ottawa Scale (NOS) criteria.Out of 535 studies identified in the initial research, only two articles were included in the present review. A significant association between MIH-HSPM and dental caries in permanent dentition was reported in the two included records (AOR: 3.70; p < 0.001). Children with MIH-HSPM expressed significantly higher DMFT and PUFA values than children without MIH-HSPM. However, dmft values did not differ significantly between children with and without HSPM (1.79 [2.4] vs. 1.78 [2.5]; 1.88 [2.73] vs. 1.59 [2.53], respectively.MIH-HSPM lesions were correlated with a higher prevalence and more severe carious lesions in permanent dentition. However, the results should be interpreted cautiously because the findings were generated by only two studies performed by the same authors. Thus, further well-designed studies are highly recommended.

Analysis of Human and Microbial Salivary Proteomes in Children Offers Insights on the Molecular Pathogenesis of Molar-Incisor Hypomineralization

Molar incisor hypomineralization is a complex developmental enamel defect that affects the permanent dentition of children with significant functional and aesthetic implications. Saliva is an ideal diagnostic tool and ensures patients’ compliance by diminishing the discomfort especially in pediatric population. Lately, salivary proteome analysis has progressively evolved in various biomedical disciplines. As changes in saliva composition are associated with oral diseases, it is reasonable to assume that the saliva proteome of MIH-affected children might be altered compared to healthy children. This study analyzed the human and microbial salivary proteome in children with MIH in order to identify salivary markers indicative of the pathology. The conducted proteomic analysis generated a comprehensive dataset comprising a total of 1515 high confidence identifications and revealed a clear discrimination between the two groups. Statistical comparison identified 142 differentially expressed proteins, while the pathway analysis indicated deregulation of inflammation, immune response mechanisms, and defense response to bacteria in MIH patients. Bacterial proteome analysis showed a lower diversity for the microbial species, which highlights the dysbiotic environment established in the MIH pathology.

Association between hypomineralization of deciduous and molar incisor hypomineralization and dental caries

This study aimed to evaluate the association between the severity of hypomineralized second primary molars (HSPM), molar-incisor hypomineralization (MIH) and dental caries in children. 450 children between the ages of 6 and 7 years were included in this cross-sectional study. A calibrated examiner classified the enamel hypomineralizations and dental caries lesions using the MIH and HSPM and the Nyvad criteria, respectively. The primary outcome was the severity of MIH according to the severity of HSPM. Statistical analysis was performed using the generalized linear model and ordinal logistic regression. The prevalence of concomitant MIH and HSPM was 26% sex and age adjusted. Mild enamel defects were more frequent than severe enamel defects. An association was found between the severity of MIH and HSPM, both for mild defects (OR=87.54; 95%CI: 55.87, 137.17) and severe defects (OR=82.15; 95%CI: 45.72, 147.61). The severity of hypomineralization in permanent molars was associated with the activity of dental caries lesions (OR=29.85; 95%CI: 12.95, 68.83). To conclude, there is a strong association between the severity of HSPM and MIH, which is more significant in the presence of active dental caries lesions.

Molar Incisor Hypomineralization—Influence on Dental Caries Experience Indexes: A Cross-sectional Study

Aim and and objective

To evaluate the influence of the clinical characteristics inherent to Molar Incisor Hypomineralization on the values ​​and scores of the DMF-T and ICDAS indexes.

Materials and methods

Eight hundred and eight seven teeth were examined, from 39 individuals aged 3-14 years (8.95 ± 3.26), who had at least one first permanent molar (FPM) or second primary molar with signs of hypomineralization, according to the criteria of the European Academy of Paediatric Dentistry. Hypomineralized teeth were evaluated for the presence of restorations, post-eruptive breakdowns (PEB), and dental caries, being considered sound for the DMF-T when there was the presence of PEB without caries lesion. Chi-square and Kruskal Wallis tests (p ≤ 0.05) were used to detect differences.

Results

Two hundred and five teeth showed signs of hypomineralization. The average number of opacities was influenced by the period of dentition, with more opacities when the primary dentition and the eruption of FPM and permanent incisors were complete (p ≥ 0.05). Hypomineralized teeth showed a higher DMF-T value, mainly of the decayed component (12%), in contrast to 2.5% of nonhypomineralized teeth. It was not possible to associate ICDAS scores 1 and 2 to hypomineralized surfaces, due to the overlap with the diagnosis of early enamel caries. The values ​​of this index changed in the presence of cavitation by caries (scores 3,4,5,6), but not in the presence of PEB.

Conclusion

Due to the impossibility of differential diagnosis with caries lesion, PEB, and opacities present in hypomineralized teeth tend to overestimate the values ​​and scores of the DMF-T and ICDAS, respectively.

Clinical significance

Make future suggestions for epidemiological studies in the area.

How to cite this article

Vieira FG, Pintor AV, Silva FD, et al. Molar Incisor Hypomineralization—Influence on Dental Caries Experience Indexes: A Cross-sectional Study. Int J Clin Pediatr Dent 2022;15(1):65-68.

Protocol for a Case Control Study to Evaluate Oral Health as a Biomarker of Child Exposure to Adverse Psychosocial Experiences

Background: The early identification of children who have experienced adversity is critical for the timely delivery of interventions to improve coping and reduce negative consequences. Self-report is the usual practice for identifying children with exposure to adversity. However, physiological characteristics that signal the presence of disease or other exposures may provide a more objective identification strategy. This protocol describes a case–control study that assesses whether exposure to adversity is more common in children with tooth enamel anomalies compared to children without such anomalies. Methods: For 150 mother–child pairs from a pediatric dental clinic in Toronto, Canada, maternal interviews will assess the child’s adverse and resilience-building experiences. Per child, one (exfoliated or extracted) tooth will be assessed for suspected enamel anomalies. If anomalies are present, the child is a case, and if absent, the child is a control. Tooth assessment modalities will include usual practice for dental exams (visual assessment) and modalities with greater sensitivity to identify anomalies. Conclusion: If structural changes in children’s teeth are associated with exposure to adversity, routine dental exams could provide an opportunity to screen children for experiences of adversity. Affected children could be referred for follow-up.

Molar-incisor hypomineralisation: an updated view for aetiology 20 years later

BACKGROUND

The term Molar-Incisor Hypomineralisation (MIH) was introduced in 2001 by Weerheijm, Jälevik and Alaluusua, and describes a defect of systemic origin that affects one to four first permanent molars, often associated with permanent incisors. In the past 20 years, this definition dictated the work regarding MIH prevalence, associated risk factors, association with dental caries, impact on quality of life, and therapeutic options.

PURPOSE

In this report, we offer an updated and comprehensive view of MIH centred on the patient and the tooth.

CONCLUSION

MIH today is globally recognized as a potential public health problem and it is not a defect of purely systemic origin but rather a condition with complex aetiology that in some instances may be the result of gene-environmental interactions.

Perinatal hypoxia and the risk of severe Molar-Incisor Hypomineralisation (MIH): a retrospective analysis of the pH value of umbilical arterial blood after birth

PURPOSE

Molar-Incisor Hypomineralisation (MIH) remains a widespread developmental disorder of the teeth with a still largely unknown etiology. Perinatal events were blamed in previous studies for the development of MIH. The aim of the present study was to evaluate the influence of perinatal hypoxia-determined by the pH value of the umbilical cord blood-and to investigate its correlation with severe MIH retrospectively. In addition, cesarean section was recorded as differentiation variable.

METHODS

A total number of 138 children (mean age 8.0 years ± 1.7), who were treated for severe MIH in a dental office in Berlin between the years 2008 and 2019, were included in the study. The control group was comprised of patients with the same date of birth (44 children, mean age 7.7 years ± 1.7). Information on the pH value of the arterial blood from the umbilical cord taken immediately after birth, whose recording is mandatory in Germany, was received from the parents by letter survey requesting the entries from the German Child Health Booklet.

RESULTS

In the group of the male children born without cesarean section, the pH value of the control group was significantly lower (7.19 ± 0.09) than the pH value of the MIH group (7.27 ± 0.07, p = 0.0008). In female children born with or without cesarean section as well as in male children born by cesarean section there were no significant differences between the MIH and control group.

CONCLUSIONS

No significant association between MIH and the pH value of the umbilical cord blood or birth by cesarean section could be found in the examined patient population.

Does molar-incisor hypomineralization (MIH) affect only permanent first molars and incisors? New observations on permanent second molars

BACKGROUND

The second permanent molar plays an important role when considering extraction of first permanent molars severely affected by molar-incisor hypomineralization (MIH).

AIM

To assess the association between MIH and enamel hypomineralization of the second permanent molars in terms of presence and severity.

DESIGN

In this retrospective cross-sectional study, permanent teeth were evaluated in 453 patients between the ages of 13 and 16 at a dental clinic, using intraoral photographs. A calibrated examiner classified enamel hypomineralization using the MIH index and dental caries experience using the DMFT and DMFS indices. Statistical analyses were performed using a linear generalized model and ordinal logistic regression.

RESULTS

The most commonly affected teeth by enamel hypomineralization were permanent molars, whereas incisors, premolars, and canines were less affected. The presence of severe defects in the first permanent molars was associated with mild defects in the second permanent molars (OR = 4.01; 95% CI: 2.50-7.77). Enamel hypomineralization was associated with increased caries experience (PR = 5.54; 95% CI: 3.81-9.06).

CONCLUSION

Enamel hypomineralization mainly affects the first and second permanent molars. Mild defects in the second permanent molars tend to be more frequent in patients with severe MIH in the first permanent molars. The presence of enamel hypomineralization was associated with higher dental caries experience.

Loads of continuous mechanics for uprighting the second molar on the second molar and premolar

INTRODUCTION

This paper aims to evaluate the effect of tube height on uprighting a mandibular second molar with a continuous arch, specifically the main effects on the molar tube and the side effects on the second premolar bracket.

METHODS

Slot brackets (0.18-in) and tubes were passively bonded from the left second molar to the right second premolar of the patient's cast and fixed to an orthodontic force tester. A mesially tipped second molar along with its tube was positioned at 5 different heights in relation to the bracket slots of the remaining appliance: 2 mm below (group -2), 1 mm below (group -1), leveled (group 0), 1 mm above (group 1) and 2 mm above (group 2). Each group had 10 different 0.016 × 0.022-in superelastic nickel-titanium wires tied one at a time to the appliance to register the vertical forces (Fz) and tipping moments (Mx) produced at the molar tube and the premolar bracket, statistically. Analysis of variance was used to identify differences of load among the groups for wire response to the position of the tube in relation to the other brackets' slots.

RESULTS

As the molar tube was positioned more occlusally, Fz and Mx decreased at the molar tube from 1.31 N to 0.75 N and 13.98 N.mm to 11.84 N.mm, respectively, whereas at the premolar bracket, Fz and Mx decreased from 1.52 N to 0.88 N and 8.77 N.mm to 1.05 N.mm, respectively.

CONCLUSIONS

In all groups, the load system at the molar tube (the main effects) registered a distal tipping moment and an extrusive force, whereas at the premolar bracket, the load system (side effects) included a distal tipping moment and an intrusive force. As the tube moved occlusally, the extrusive force and the uprighting moment decreased, along with the side effects at the premolar bracket. Attempting to bond the molar tube more occlusally (within reasonable intraoral dimensions) when trying to upright a molar does not appear to be sufficient to keep a molar from extruding.

[Molar incisor hypomineralisation (MIH)-discussion of prevalence and etiology with special reference to the results from the Munich birth cohorts GINIplus and LISA]

After caries, molar incisor hypomineralisation (MIH)-also known as chalky teeth-is one the most common dental diseases in children and adolescents. In addition to aesthetic limitations, especially on the anterior teeth, hypersensitivities and enamel breakdowns on permanent molars are of functional importance. While the MIH prevalence rates range from ~ 10% to ~ 30% and is well described, the situation regarding aetiology is unsatisfactory. Although efforts have been made in the past to clarify the aetiology, no plausible reason is available so far. Aetiology research has to be judged as methodologically challenging, since it should ideally be embedded in prospectively planned birth cohort studies. The aim of this article is to summarize typical clinical characteristics of MIH, epidemiological findings and potential causes with special reference to the earlier published results from the two Munich birth cohort studies GINIplus and LISA.

Molar incisor hypomineralization: A review and prevalence in Japan

Molar incisor hypomineralization (MIH) is defined as hypomineralization of systemic origin of one to four first permanent molars, and incisors are also frequently affected. This disorder is a serious concern in pediatric dentistry. Teeth affected by MIH have many dental problems, such as hypersensitivity, poor aesthetics, and rapid progression of dental caries. The prevalence of MIH ranges from 2.8% to 21% among studies with more than 1000 subjects in different countries and age groups. The etiology of MIH is unclear, but genetic and environmental factors have been proposed. This review describes the prevalence, etiology, and clinical management of MIH. A detailed description of MIH prevalence in Japan is also provided.

Etiology of Molar-Incisor Hypomineralization (MIH): A Cross-Sectional Study of Saudi Children

(1) Background: Molar-incisor hypomineralization (MIH) is a common clinical condition with critical negative consequences for dental health. The etiology of MIH is still not completely understood, although several theories have been suggested. (2) Aim: To investigate the etiology of MIH defects in a sample of Saudi school children. (3) Method: A total of 893 school children in the age range of 8–10 years participated in the study. The sample was taken from Riyadh City, Saudi Arabia. The participating children were examined for MIH using the European Academy of Pediatric Dentistry Criteria. The children’s parents were asked about the child’s pre, peri-, and postnatal condition utilizing a structured and validated questionnaire. (4) Results: A total of 362 children (168 males and 194 females) were affected with MIH, for a prevalence of 40.5%. Among all analyzed etiological factors, only jaundice was found to be significantly associated with MIH in children (OR = 1.35, p = 0.047). Multivariate logistic regression analysis confirmed that the only significant etiological factor for MIH was newborn jaundice (p = 0.04). (5) Conclusion: Newborn jaundice was the only etiological factor that showed a significant association with MIH in the studied Saudi school children.

Inheritance pattern of molar-incisor hypomineralization

The aim of this study was to investigate the segregation patterns of molar incisor hypomineralization (MIH) in families, given the evidence that its etiology is influenced by genetics. Clinically, MIH may be detected in parents and/or siblings of MIH-affected children. Our study included children with at least one first permanent molar affected by MIH (proband) and their first-degree relatives (parents and siblings). The participants were examined clinically to detect MIH, according to the European Academy of Paediatric Dentistry criteria (2003). A total of 101 nuclear families (391 individuals) were studied. Proband diagnosis was followed by MIH classification of the subject, his parents and siblings, as affected, unaffected, or unknown. Segregation analysis was performed using the multivariate logistic regression model of the Statistical Analysis for Genetic Epidemiology package, and segregation models (general transmission, environmental, major gene, dominant, codominant and recessive models). The Akaike information criterion (AIC) was used to evaluate the most parsimonious model. In all, 130 affected individuals, 165 unaffected individuals, and 96 unknown individuals were studied. Severe MIH was found in 50.7% of the cases. A segregation analysis performed for MIH revealed the following different models: environmental and dominance (p = 0.05), major gene (p = 0.04), codominant (p = 0.15) and recessive models (p = 0.03). According to the AIC values, the codominant model was the most parsimonious (AIC = 308.36). Our results suggest that the codominant model could be the most likely for inheriting MIH. This result strengthens the evidence that genetic factors, such as multifactorial complex defect, influence MIH.

Enamel opacities in all other than Molar Incisor Hypomineralisation index teeth of adolescents

BACKGROUND

There are scarce data on the hypomineralisation of other permanent teeth (HOPT) than the index teeth of Molar Incisor Hypomineralisation (MIH).

AIM

To report on the prevalence and surface pattern of HOPT and seek associations with MIH.

DESIGN

Representative samples of urban Greek 14-year-olds were examined in classroom with a dental mirror. Their enamel defects were recorded using EAPD criteria for MIH. Descriptive statistics and correlation tests for HOPT vs previously reported MIH findings in the same samples were applied.

RESULTS

HOPT prevalence in 1156 consented adolescents was 22.9%. 148 (16.2%) of 912 no-MIH children had HOPT; 117 (48.1%) of the 244 MIH children had HOPT too (OR 3.0, 95% CI 2.4-3.6). There were more HOPT teeth per child in the MIH vs no-MIH children (P < .001). HOPT tooth frequency was as follows: second molar 33.7%, canine 25.7%, first premolar 23.6%, and second premolar 17.0%. Enamel breakdown was seen in 5.3% HOPT children. Vestibular to intraoral surface defect ratio differed between jaws (maxilla 187/88, mandible 149/17, P < .05).

CONCLUSIONS

Hypomineralisation defects in the MIH non-index teeth collectively had comparable prevalence and tooth surface patterns to MIH, but much lower severity. MIH was predictor for HOPT.

Molar Incisor Hypomineralization (MIH) in a Child with Congenital Chronic Intestinal Pseudoobstruction (CIPO)

Molar incisor hypomineralization (MIH) is a qualitative enamel defect of systemic origin affecting 1-4 permanent first molars (PFMs) frequently in association with affected permanent incisors (PIs). The exact etiology of MIH is still unclear but considered to be multifactorial. This present case report to the best of our knowledge is the first case reported which acknowledges MIH in a patient with chronic intestinal pseudoobstruction (CIPO) with underlying neurological disease due to somatic mitochondrial disorder. It also elicits the availability of various contemporary treatment options and their proper selection and early intervention to manage the functional and aesthetic problems caused by enamel defects and to improve the quality of life in the patients.

Gene-environment interaction in molar-incisor hypomineralization

Molar incisor hypomineralization (MIH) is an enamel condition characterized by lesions ranging in color from white to brown which present rapid caries progression, and mainly affects permanent first molars and incisors. These enamel defects usually occur when there are disturbances during the mineralization or maturation stage of amelogenesis. Both genetic and environmental factors have been suggested to play roles in MIH’s development, but no conclusive risk factors have shown the source of the disease. During head and neck development, the interferon regulatory factor 6 (IRF6) gene is involved in the structure formation of the oral and maxillofacial regions, and the transforming growth factor alpha (TGFA) is an essential cell regulator, acting during proliferation, differentiation, migration and apoptosis. In this present study, it was hypothesized that these genes interact and contribute to predisposition of MIH. Environmental factors affecting children that were 3 years of age or older were also hypothesized to play a role in the disease etiology. Those factors included respiratory issues, malnutrition, food intolerance, infection of any sort and medication intake. A total of 1,065 salivary samples from four different cohorts were obtained, and DNA was extracted from each sample and genotyped for nine different single nucleotide polymorphisms. Association tests and logistic regression implemented in PLINK were used for analyses. A potential interaction between TGFA rs930655 with all markers tested in the cohort from Turkey was identified. These interactions were not identified in the remaining cohorts. Associations (p<0.05) between the use of medication after three years of age and MIH were also found, suggesting that conditions acquired at the age children start to socialize might contribute to the development of MIH.

Estimating molar-incisor-hypomineralization among 8-year-olds based on 15-year public oral health practice-based data

Background: A wide range in the prevalence of molar-incisor-hypomineralization (MIH) has been reported. Population-based studies are recommended. However, such studies are expensive and time-consuming.Objectives: To estimate the magnitude of MIH condition among 8-year-olds based on routine oral health examinations and to associate first permanent molar (FPM) affection with that of other permanent teeth over time.Materials and methods: This retrospective study, with cross-sectional and longitudinal components, was based on electronic oral health records; all 8-year-olds examined between 2002 and 2016 were included.Results: The average estimated prevalence of MIH was 8.3%; yearly range was 4.8-15.9%. The mean number of affected teeth was 1.4; 62% had one affected tooth. One-surface defects were the most frequent (66%). Asymmetric distribution of affected teeth was observed. In follow-up, 10.7%, 8.4%, and 11.2% had at least one affected permanent canine, premolar, or second permanent molar, respectively. The proportion of children with other MIH-affected permanent teeth was higher in the group with ≥2 MIH-affected teeth than in group with one affected FPM at the age of 8.Conclusions: The average prevalence of MIH was comparable to that reported elsewhere. The number of MIH-affected teeth at early mixed dentition predicts the affection of other permanent teeth over time, mainly that of permanent canines. Further screening of children with MIH is recommended to improve individually tailored early preventive and restorative dental care.

The effect of amoxicillin on dental enamel development in vivo

The exposure to amoxicillin has been associated with molar incisor hypomineralization. This study aimed to determine if amoxicillin disturbs the enamel mineralization in in vivo experiments. Fifteen pregnant rats were randomly assigned into three groups to received daily phosphatase-buffered saline or amoxicillin as either 100 or 500 mg/kg. Mice received treatment from day 13 of pregnancy to day 40 postnatal. After birth, the offsprings from each litter continued to receive the same treatment according to their respective group. Calcium (Ca) and phosphorus (P) content in the dental hard tissues were analyzed from 60 upper first molars and 60 upper incisors by the complexometric titration method and colorimetric analysis using a spectrophotometer at 680 nm, respectively. Lower incisors were analyzed by X-ray microtomography, it was measured the electron density of lingual and buccal enamel, and the enamel and dentin thickness. Differences in Ca and P content and electron density among the groups were analyzed by one-way ANOVA. There was no significant difference on enamel electron density and thickness among the groups (p > 0.05). However, in incisors, the higher dose of amoxicillin decreased markedly the electron density in some rats. There were no statistically significant differences in Ca (p = 0.180) or P content (p = 0.054), although the higher dose of amoxicillin could affect the enamel in some animals. The amoxicillin did not significantly alter the enamel mineralization and thickness in rats.

Prevalence of molar-incisor-hypomineralisation (MIH) among 6-12-year-old children in Central Hesse (Germany)

AIM

The aim of the present cross-sectional study was to assess and compare the prevalence of MIH among 6-12-year-old school children living either in a rural area of Central Hesse (Germany) or in the city of Frankfurt on the Main (Germany). A possible association between hypomineralised second primary molars (HSPM) and MIH was investigated. Furthermore, the MIH prevalence data of the rural area were compared with those of a previous study conducted in this area in the school year 2002/2003.

METHODS

In the school year 2014/2015, 2103 children (6-12 years of age) were examined during the annual school-based dental examinations prescribed by law at nine schools in the rural area of Central Hesse (LDK) and five schools in the city of Frankfurt on the Main (Ffm). Eight previously calibrated dentists working for the public healthcare authorities assessed the prevalence of HSPM/MIH (EAPD criteria/severity scale by Wetzel and Reckel) and the caries experience (dmft/DMFT).

RESULTS

The prevalence of HSPM/MIH amounted 3.2%/9.4% in LDK and 2.9%/17.4% in Ffm. In the majority of cases, children with MIH had demarcated opacities. In LDK, hypomineralised first permanent molars were most commonly affected by severity degree 2, whereas in Ffm, severity degree 1 was predominant. Children suffering from HSPM had an odds ratio of 11.32 (95% CI: 6.73-19.03) for having MIH as well. Compared with the results of 2002/2003 in LDK (prevalence of MIH 5.9%), the MIH prevalence increased by 3.5% in the rural area. All in all, the caries experience among children under investigation was low (DMFT 0.14-0.15).

SIGNIFICANCE

MIH may be diagnosed in school children living in different areas of Germany with regional variations (rural-urban comparison). The presence of HSPM is of predictive value for MIH. The increasing number of hypomineralised first permanent molars over 12 years of time in the rural area indicates a need for further investigation on the aetiology of MIH.

The possible influence of genetic aetiological factors on molar-incisor hypomineralisation

OBJECTIVE

The present study searched for evidence of possible associations between some genetic factors that could affect the development of molar-incisor hypomineralisation (MIH).

METHODS

In 113 patients who were surgically treated at an Otorhinolaryngology and Cervicofacial Surgery Clinic (ORL) during early childhood, human leukocyte antigen (HLA) DQ2 and DQ8 haplotypes and single nucleotide polymorphisms (SNP) of eight amelogenesis-related genes were searched in genomic DNA. Genotypes were determined by high resolution melting (HRM), TaqMan genotyping assays, and Sanger sequencing. Association between MIH and the HLA DQ2 and DQ8 alleles was tested using a univariate logistic regression. The significance of genetic variants was analysed using the Cochran-Armitage tests for trend and the Fisher exact tests.

RESULTS

We identified MIH in 22 (19.5 %) of the 113 children. Among the evaluated genetic variants, SNP rs2245803 in the MMP20 gene in a homozygous form in a recessive model was associated with MIH development (OR, 2.796; 95 %CI, 1.075 - 4.783; p = 0.0496) with the genotype distribution of TT(3), TG(6) or GG(13) in children with MIH and distribution of TT(18), TG(42) or GG(31) in children without MIH.

CONCLUSIONS

While the aetiology of MIH remains unclear, our findings suggest that variants of genes associated with amelogenesis may play important roles in susceptibility to MIH.

Molar Incisor Hypomineralisation-To Extract or to Restore beyond the Optimal Age?

The management of compromised first permanent molars (FPMs) in children presents a clinical challenge to the dental team. Hypomineralised FPMs in molar incisor hypomineralisation (MIH) conditions could undergo post-eruptive breakdown, making them susceptible to caries, leading to their subsequent loss. The planned extraction of compromised FPMs is a valid alternative to complex restorative treatment. However, establishing the presence or absence of third permanent molars, amongst other considerations, is crucial to reaching a successful outcome. Clinicians should understand the importance of an orthodontic examination around the age of 8 years old with regard to establishing a differential therapeutic decision about the ideal timing of MIH-affected FPMs’ extraction in children. The aim of this article is to highlight that, with an interdisciplinary approach, a good outcome can be achieved following the extraction of poorly prognosed FPMs. The most cost-effective way of addressing MIH-affected FPMs is extraction, followed by orthodontic space closure when indicated. This obviates the need for the repeated restorative replacement and saves perfectly healthy premolars from being extracted for space creation in orthodontic treatment in several clinical scenarios.

Molar Incisor Hypomineralization: Etiology, Clinical Aspects, and a Restorative Treatment Case Report

CLINICAL RELEVANCE

Total-etch adhesive systems and resin composite are clinically viable dental materials for esthetic restorations in teeth presenting white/yellow/brown hypomineralization stains.

SUMMARY

Molar-incisor hypomineralization (MIH) is a condition that negatively affects enamel and dentin, especially the first molars and permanent incisors, causing esthetic and functional problems. The present clinical case report presents and discusses the etiology and clinical characteristics of MIH and describes a restorative protocol for MIH-affected teeth.

The relationship between molar incisor hypomineralization, dental caries, socioeconomic factors, and polymorphisms in the vitamin D receptor gene: a population-based study

OBJECTIVES

The purpose of this cross-sectional study was to investigate whether polymorphisms in vitamin D receptor (VDR) genes increase the prevalence of dental caries, molar incisor hypomineralization (MIH), and hypomineralized primary second molars (HPSM).

MATERIAL AND METHODS

A representative population-based sample of 731 schoolchildren, 8 years of age, was randomly selected in Curitiba, Paraná, Brazil. MIH, HPSM, and dental caries were clinically assessed by four calibrated examiners (kappa > 0.80) using European Academy of Pediatric Dentistry (2003) criteria, the modified Developmental Defects of Enamel (DDE) index, and the Decayed, Missing, or Filled Teeth (DMFT) index by the World Health Organization (2013), respectively. The VDR rs739837 and rs2228570 polymorphisms were genotyped using real-time polymerase chain reaction. Associations were analyzed by Poisson regression with robust variance (α = 0.05).

RESULTS

Schoolchildren with MIH presented a higher prevalence of dental caries (DMFT > 1, PR = 2.52, confidence interval = 1.60-3.97, p ≤ 0.001). No association was observed between MIH, HPSM, and dental caries, with rs739837 and rs2228570 polymorphisms. Individuals with the GT/GG genotype in rs739837 polymorphism presented a higher prevalence of MIH in molars and incisors than individuals TT (PR = 2.34, confidence interval = 1.08-5.07, p = 0.03).

CONCLUSION

Children with MIH presented a significant higher prevalence of dental caries than children without MIH. To carry at least one G allele in rs739837 was associated to higher prevalence of MIH in molars and incisors.

CLINICAL RELEVANCE

Our findings suggested that more severe cases with incisors affected by MIH could be associated with polymorphism in VDR gene.

Are the Internet users concerned about molar incisor hypomineralization? An infoveillance study

BACKGROUND

Molar incisor hypomineralization (MIH) is a developmental enamel defect characterized by well-demarcated discolorations frequently detected in molars, causing pain and esthetic alterations.

AIM

To assess the interests of Google users on MIH-related information.

DESIGN

Digital data were collected in Google Trends through two search strategies, 'molar incisor hypomineralization' (topic) and 'MIH' (search term), between January 2004 and November 2018. ARIMA models were applied to analyze trends of curves and to predict the activity of Google users during 12 months. Autocorrelation and partial autocorrelation (ACF/PACF) plots were used to detect trends in the variation of relative search volume (RSV) related to search strategies over time. The most popular queries were analyzed qualitatively, whereas geographical heat maps were retrieved to determine search volumes according to countries (P < .05).

RESULTS

Gradual increasing trends were detected, with forecasts indicating similar levels of RSVs to the period between December 2017 and November 2018. Most popular queries and topics were associated with MIH diagnosis, being retrieved predominantly in European countries.

CONCLUSIONS

The activity of Google users related to this condition is maintained low, with a reduced intensification over time, suggesting that the awareness on MIH is probably confined to dentists and affected people worldwide.

Evaluating the changes in molar incisor hypomineralization prevalence: A comparison of two cross-sectional studies in two elementary schools in Mexico City between 2008 and 2017

Background

Little information is available on the trends over time of the prevalence of molar incisor hypomineralization (MIH). This condition may be preventing dental caries decline.

Aim

(a) To compare the prevalence of MIH, in Mexico City schoolchildren, evaluated in 2008 with a group evaluated in 2017, (b) to identify the association of MIH with dental caries, and (c) to assess the mother's perception of her child's oral health status.

Design

Two cross‐sectional studies performed in 2008 and in 2017 were compared. The oral examiner and the selected schools were the same in both surveys.

Results

A total of 549 schoolchildren were evaluated. The prevalence of MIH in the first survey was 20.3%, and 31.9 % in the second survey, (p = .002). Children with MIH were more likely to have dental caries. The odds ratio was 2.24 (p = .036) and 4.18 (p ˂ .001) in the first and second surveys, respectively. Mothers of children with MIH perceived worse oral health status of their children than the mothers whose children did not have MIH (odds ratio = 4.47, p ˂ .001).

Conclusion

The findings portray a clear increase in prevalence of MIH and highlight the need for increased awareness about this condition among dentists and the general population.

A systematic review and meta-analysis of systemic exposure associated with molar incisor hypomineralization

OBJECTIVE

To evaluate systemic exposures associated with molar incisor hypomineralization (MIH).

METHODS

This systematic review was performed using published observational studies that evaluated the systemic exposures associated with MIH. The sources of articles searched were PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library and Grey literature. The risk of bias was analysed according to the Newcastle-Ottawa Scale for quality assessment. The meta-analysis was performed considering the exposures during the prenatal, perinatal and postnatal periods using the CMA software.

RESULTS

A total of 4207 articles were identified. Twenty-nine studies were eligible for inclusion and 27 were included in the meta-analysis. The studies presented low and moderate risks of bias, except for one that was classified as having a high risk of bias. Maternal illness during pregnancy (OR 1.40; 95% CI 1.18-1.65, P < 0.0001) and psychological stress (OR = 2.65; 95% CI 1.52-4.63; P = 0.001) was observed to be significantly associated with higher odds of MIH. During the perinatal period, caesarean delivery (OR = 1.32, 95% CI 1.11-1.57, P = 0.001) and delivery complications (OR = 2.06; 95% CI 1.47-2.88, P < 0.0001) were also associated with MIH. In the postnatal period, only respiratory diseases (OR = 1.98; 95% CI 1.45-2.70, P < 0.0001) and fever (OR = 1.50; 95% CI 1.22-1.84; P < 0.0001) were associated with higher prevalence of MIH. The evidence was graded as very low quality.

CONCLUSIONS

Maternal illness, psychological stress, caesarean delivery, delivery complications, respiratory diseases and fever during the first years of a child's life were significantly associated with a higher odds of MIH. However, this should be interpreted with caution, once the primary studies were observational, with serious limitations according to the risk of bias, imprecision, and inconsistency. Further, well-designed cohort studies are still required.

Hipomineralização molar incisivo em odontopediatria: considerações gerais

Hipomineralização molar incisivo (MIH) engloba a hipomineralização do esmalte que aflige um ou mais primeiros molares permanentes e que pode acometer também incisivos permanentes. Segundos pré-molares e caninos permanentes também podem mostrar-se envolvidos, assim como alguns decíduos, entre os quais cita-se os segundos molares. O objetivo do presente artigo foi averiguar as manifestações clínicas ocasionadas pela hipomineralização molar incisivo sob o enfoque da odontopediatria. Realizou-se estudo de revisão bibliográfica com busca nas bases de dados LILACS e Google Acadêmico. Na base LILACS empregou-se a expressão de busca: hipomineralização molar incisivo and odontopediatria. Na base de dados Google Acadêmico utilizou-se a expressão de busca: hipomineralização molar incisivo and odontopediatria. É importante que se proceda ao diagnóstico precoce e correto da MIH, baseando-se na realização de anamnese detalhada, que seja capaz de investigar a existência de possíveis doenças no período da infância e que se proceda concomitantemente ao feitio de exame clínico para que se estabeleça um prognóstico adequado. Concluiu-se que uma abordagem com cunho preventivo é capaz de minimizar eventuais danos, evitando tratamentos com maior complexidade.

On the Variable Clinical Presentation of Molar-Incisor Hypomineralization

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Original reports on the etiology of the condition and possible risk factors were inconclusive, and we refuted the original suggestion that MIH is an idiopathic condition and suggested that MIH has complex inheritance and is due to the interaction of more than one gene and the environment. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. Later we expanded this work to include genes related to the immune response. In this report, we provide a rationale to explain the variation seen in the clinical presentation of MIH, which can affect just one molar out of the four or just a portion of a particular molar.

Etiology of Hypomineralized Second Primary Molars: A Prospective Twin Study

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.

Prevalence and etiology of molar-incisor hypomineralization (MIH) in the city of Istanbul

Background/purpose

Molar-Incisor-Hypomineralisation (MIH) is the term used to depict a condition in which one or more of the permanent molar teeth and usually no less than one incisor tooth is hypomineralised and the prevalence rates vary from 2.4 to 40.2%. The aim of this study was to assess the prevalence and the risk factors of MIH in children in Istanbul, Turkey.

Materials and methods

A total of 1511 (760 M, 751 F), 8- to 11-year-old children were examined who had their first permanent molar and incisors evaluated using the EAPD criteria for MIH. Hypomineralized molars and incisors were recorded based on developmental defects of enamel index. The potential aetiological factors were retrieved through personal interview and etiological questions were asked to the parents. Statistical analysis was performed with a chi-Square test.

Results

MIH was observed in 215 (14.2%; 102 male, 113 female) children. The sample (1511 children) comprised 71 (9.9%) 8 year-olds with MIH and 144 (18.2%) 11 year-olds with MIH. A significant difference was found between 8 (9.9%) and 11-year-old (18.2%) children with MIH (p ≤ 0.001). Complications during the mother's pregnancy, birth prematurity, average breast feeding period, diarrhea frequency, digestive system diseases, asthma, frequent high fever, ear infection, renal failure, rubeola, chickenpox and parotitis were found to be significantly associated with MIH (p < 0.001).

Conclusion

There are many events that can cause MIH which we cannot control or predict. Therefore, longitudinal studies with large sample size are needed so as to determine how various likely etiological factors described affect the etiological role.

Investigation of Clinical Characteristics and Etiological Factors in Children with Molar Incisor Hypomineralization

Aim

The purpose of the present study was to evaluate the clinical defects and etiological factors potentially involved in the onset of MIH in a pediatric sample.

Methods

120 children, selected from the university dental clinic, were included: 60 children (25 boys and 35 girls; average age: 9.8 ± 1.8 years) with MIH formed the test group and 60 children (27 boys and 33 girls; average age: 10.1 ± 2 years) without MIH constituted the control group. Distribution and severity of MIH defects were evaluated, and a questionnaire was used to investigate the etiological variables; chi-square, univariate, and multivariate statistical tests were performed (significance level set at p < 0.05).

Results

A total of 186 molars and 98 incisors exhibited MIH defects: 55 molars and 75 incisors showed mild defects, 91 molars and 20 incisors had moderate lesions, and 40 molars and 3 incisors showed severe lesions. Univariate and multivariate statistical analysis showed a significant association (p < 0.05) between MIH and ear, nose, and throat (ENT) disorders and the antibiotics used during pregnancy (0.019).

Conclusions

Moderate defects were more frequent in the molars, while mild lesions were more frequent in the incisors. Antibiotics used during pregnancy and ENT may be directly involved in the etiology of MIH in children.