Which are the clinical consequences of Molar Incisor hypomineralization (MIH) in children and adolescents? Systematic review and meta-analysis.

OBJECTIVE: This systematic review was conducted to address the following research question: "What are the clinical consequences (outcome) of Molar Incisor Hypomineralization (MIH) (exposure) in children and adolescents (population/patient)?". MATERIAL AND METHODS: After defining the strategy, a search was performed in different databases (MEDLINE via Pubmed, Cochrane Library, BBO, LILACS, Scopus, Web of Science, Embase) and Grey literature in August 2023. Cross-sectional observational studies that identified clinical consequences of MIH (dental caries, post-eruptive structural loss, atypical restorations, hypersensitivity and tooth extraction) were included. The risk of bias was assessed following the Joanna Briggs Institute protocol for cross-sectional studies. Meta-analyses were conducted for each outcome, taking into account the number of patients and teeth. The effect measure considered was the prevalence; random-effects model was adopted. Heterogeneity was assessed using I2 statistics and prediction intervals (PI). RESULTS: A total of 903 studies were identified; 41 were selected for qualitative analysis and 38 for quantitative analysis. Twenty eight studies were classified as presenting uncertain risk of bias, 11 as low risk and 3 as high risk of bias. The prevalence levels, ranked from highest to lowest and considering the tooth and patient units, respectively, were: caries lesions (0.252 - 95% CI 0.158-0.375; 0.512 - 95% CI 0.385-0.639); hypersensitivity (0.286 - 95% CI 0.190-0.407; 0.417 - 95% CI 0.197-0.674), post-eruptive fracture (0.125 - 95% CI 0.099-0.158; 0.257 - 95% CI 0.145-0.412); atypical restorations (0.048 - 95% CI 0.030-0.077; 0.167 - 95% CI 0.096 - 0.274); tooth extraction (0.012 - 95% CI 0.007-0.019; 0.090 - 95% CI 0.019 - 0.331). All meta-analyses resulted in heterogeneity greater than 85%, with the exception of the outcome "tooth extraction" according to the tooth unit (I2 = 57.83). This heterogeneity may be attributed to factors such as differences in the location where the study was realized, the socioeconomic conditions of the studied population, the asymmetric nature of MIH, and patient age. CONCLUSION: The most common consequences of MIH are caries lesions, hypersensitivity, and post-eruptive breakdown. (PROSPERO:CRD42020201410).

Assessment of the developmental defects of the enamel in children and adolescents with sickle cell disease: A comparative study.

BACKGROUND: Sickle cell disease (SCD) is the most important hemoglobinopathy in terms of frequency and social impact and can affect the stomatognathic system. AIM: To assess and compare the developmental defects of the enamel (DDE) in children and adolescents with and without SCD. DESIGN: This was a cross-sectional, analytical, and comparative study of 210 children and adolescents aged 5-18 years, who visited the Hematology and Hemotherapy Hospital of Pernambuco. RESULTS: Developmental defects of the enamel were observed in 55.2% of the SCD patients and 35.2% of the non-SCD patients (healthy group; p < .05). In the SCD group, DDE were more common in females than in males (69.1% vs. 40.0%; p < .05). The incidence of DDE in the permanent teeth was higher in the upper arch than in the lower arch (SCD group, 13.1% vs. 4.6%; healthy group, 8.9% vs. 3.6%; p < .05). CONCLUSION: Compared with the healthy group, the SCD patients were almost twice as likely to develop DDE, mostly affecting females and the permanent teeth. These findings suggest that individuals with SCD need early dental care to avoid future oral problems.

Is there a rise of prevalence for Molar Incisor Hypomineralization? A meta-analysis of published data.

Since Molar Incisor Hypomineralization was first described as a pathologic entity, public perception often suggests a considerable rise in prevalence of the respective disease. Since there are still considerable doubts regarding the etiology and-accordingly-prevention of MIH and respective therapeutic approaches are difficult this question is of considerable clinical and public interest. Accordingly, a systematic literature search in accordance with the PRISMA guidelines for systematic reviews on Medline, Cochrane Database, EMBASE, LILACS, Web of Science, Google scholar, Scopus was performed to retrieve original articles reporting the prevalence of MIH as defined by the European Academy of Pediatric Dentistry (EAPD). From initially 2360 retrieved titles, 344 full texts were assessed for possible inclusion and finally 167 articles of mainly moderate to high quality and based on data of 46'613 individuals were included in the meta-analysis. All studies published before 2001 had to be excluded since it was not possible to align the findings with the EAPD classification. Studies varied considerably regarding cohort size (25 to 23'320, mean 1'235)) and age (5.6-19 y, mean 9.8 y). Over all studies, the weighted mean for the prevalence for MIH was 12.8% (95% CI 11.5%-14.1%) and no significant changes with respect to either publication year or birthyear were found. A sub-analysis of eleven studies reporting on the prevalence in different age groups, however, revealed strong evidence for an increasing prevalence between the years 1992 (3%) and 2013 (13%).Therefore, based on data from cross-sectional studies a possible rise in prevalence of MIH remains unclear. Future prospective large-scale studies under standardized examination conditions with an emphasis on examiner calibration are needed to gain better understanding in the evolution of the prevalence of MIH.

Prenatal exposure to environmental toxins and comprehensive dental findings in a population cohort of children.

Environmental toxins are known to have many impacts on growth and development in humans, starting in utero. Alterations in amelogenesis, caused by chemical and physical trauma that occur during the antenatal, perinatal and postnatal time periods, may result in developmental defects in deciduous and permanent tooth enamel, as demonstrated in animal studies. These defects can be clinically visible and result in a variety of morphological and functional problems in the dentition. Since enamel does not remodel after formation, it may serve as a permanent record of insults during organ development.Our primary purpose was to investigate any possible relationship between intrauterine exposure to endocrine disrupting chemicals (phenols and phthalates) and developmental defects in enamel in children, while also accounting for fluoride exposure. Our secondary purpose was to report descriptively on findings from comprehensive dental examinations performed on 356 children that were drawn from the general paediatric population. A cohort of children from the Utah Children's Project (N = 356) that had full medical exams, comprehensive medical and family histories and available biospecimens were given extraoral and intraoral examinations. They also completed an oral health questionnaire. Standardized intraoral photographs were taken of the teeth and viewed by standardised examiners and the dental observations were recorded for a full inventory of findings, including: tooth morphology, caries, restorations, colorations, attrition, erosion, fractures and hypomineralization. Perinatal maternal urine samples were assessed for the concentration of fluoride, phenols and phthalates, including bisphenol A (BPA).Pairwise statistical analyses were done to correlate the dental findings with one another and with the presence of environment chemicals found in the urine samples. Hypomineralization was the most common finding (96% of children; 37% of deciduous teeth, 42% of permanent teeth), consistent with molar incisor hypomineralization (MIH) described in other human populations. No consistent correlations were seen between dental findings and the presence of phenols and phthalates in prenatal urine, but the number of samples available for the assessment was limited (n = 35).In conclusion, we found a high proportion of dental hypomineralization in a population based paediatric cohort, but did not find an association with prenatal exposure to phenols and phthalates.

Prevalence and clinical presentation of molar incisor hypomineralisation among a population of children in the community of Madrid.

OBJECTIVE: The main objective of this study was to estimate the prevalence of molar incisor hypomineralisation (MIH), an alteration of tooth enamel with an estimated worldwide prevalence rate of 14%, among children using primary care services in the Community of Madrid, Spain. MATERIALS AND METHODS: This was a descriptive, cross-sectional and multicentre study. After calibrating all researchers and following the diagnostic criteria of the European Academy of Paediatric Dentistry (EAPD), children aged between 8 and 16 years who were users of the dental services at 8 primary oral health units of the Madrid Health Service (SERMAS) were included. The children underwent a dental examination, and the parents were asked to complete a questionnaire. RESULTS: The prevalence of MIH was 28.63% (CI: 24.61-32.65%). The age cohorts most affected by MIH were 8 years (21.4%) and 11 years (20.7%). The presence of MIH was greater among girls (85; 60.71%) than among boys (55; 39.28%). The mean number of affected teeth per patient was 4.46 ± 2.8. The most frequently affected molar was the upper right first molar (74.3%), and the upper left central incisor was the most affected incisor (37.85%). Opacities were the defects most frequently recorded (63.57%). CONCLUSIONS: The prevalence of MIH in this study is the highest of all relevant studies conducted in Spain.

Molar-incisor hypomineralisation in Norwegian children: Prevalence and associated factors.

This study investigated the prevalence and associations of molar-incisor hypomineralisation (MIH) in 8-9 year-old children in Oslo. A total of 3013 children in one age cohort participated in the study during their regular dental examination at the Public Dental Service. Hypomineralised enamel defects were recorded according to the European Academy of Paediatric Dentistry criteria for MIH. Information on health and medications used during pregnancy and in the child's first 3 years of life was obtained from a questionnaire administered to parents. The overall prevalence of MIH was 28.2%, with no gender difference. A higher prevalence of MIH was found in children who had been ill or had used medication in early life and in those whose mother had been ill during pregnancy. No association was found between MIH and prematurity or maternal use of medication during pregnancy. The multivariable analyses showed that children with MIH were more likely to have suffered from illness in early life (OR = 1.41, 95% CI: 1.17-1.70), used antibiotics during the first year of life (OR = 1.68, 95% CI: 1.19-2.35), experienced tooth pain (OR = 1.33, 95% CI: 1.03-1.72), and experienced pain while toothbrushing (OR = 2.17, 95% CI: 1.46-3.23) than children without MIH. The prevalence of MIH was high in the children participating in this study.

Microcephaly as a risk factor for dental alterations: A case-control study.

OBJECTIVE: This study aimed to assess whether microcephaly is a risk factor for alterations in the chronology and sequence of tooth eruption and for developmental defects of enamel. MATHERIALS AND METHODS: In this case-control study, 81 children aged 30-36 months, including 40 normoreactive children and 41 with microcephaly, were submitted to oral clinical examination to determine the frequency of alterations in the chronology and sequence of tooth eruption and developmental enamel defects. The sample was matched for sex and age (1:1) and allocated to the case (presence of dental alterations) and control (absence of dental alterations) groups. Gestational age, birthweight and socioeconomic characteristics were also analyzed. Chi-square test and Fisher's exact test were applied (α = 0.05). RESULTS: Microcephaly was significantly associated with delayed tooth eruption, alterations in the sequence of tooth eruption, and defects in dental enamel (p < 0.001). Low birthweight also showed a significant association with this alterations (p < 0.005) and prematurity was associated with defects in enamel development (p < 0.005). CONCLUSION: Microcephaly is a risk factor for alterations in the tooth eruption process and enamel formation in primary teeth.

Prevalence of and factors associated with molar-incisor hypomineralisation in schoolchildren in the canton of Basel-Landschaft, Switzerland.

OBJECTIVES: As prevalence of molar-incisor hypomineralisation varies considerably in different countries and regions, the aim of this study was to obtain representative epidemiological data for schoolchildren living in the canton of Basel-Landschaft, Switzerland. MATERIAL AND METHODS: A representative population of schoolchildren of three different age groups, i.e. 1st grade (mean age: 7.4 years), 6th grade (mean age: 12.6 years), and 9th grade (mean age: 15.7 years) visiting compulsory schools in the canton of Basel-Landschaft, Switzerland, was examined. The presence or absence of molar-incisor hypomineralisation at time of examination was recorded as well as potential influencing factors such as age group, gender, nationality, or the children's place of residence. RESULTS: A total of 1252 schoolchildren could be included. On average, the prevalence of MIH in the study population was 14.8%. No statistically significant differences were found for nationality, gender, or place of residence. Although not statistically significant, children from the youngest age group had the highest while children from the oldest age group had the lowest MIH prevalence. CONCLUSION: With a mean value of 14.8%, MIH prevalence among schoolchildren living in the canton of Basel-Landschaft, Switzerland, is comparable to mean values recorded globally. CLINICAL RELEVANCE: This study represents the first study on MIH prevalence in Switzerland and also provides further evidence on potential influencing factors.

Validity of partial protocols to evaluate the prevalence of developmental defects of enamel in permanent dentition: a birth cohort study in Southern Brazil.

OBJECTIVES: To evaluate the validity of partial protocols (PP) to assess the prevalence of developmental defects of enamel (DDE) in permanent teeth and identify the strength of the association between DDE and some risk factors, using PP compared to the full-mouth (FM) exam. MATERIALS AND METHODS: This study was conducted in a population-based birth cohort of children born in 2004 in Pelotas, Southern Brazil. Socioeconomic, demographic, pre-, per-, and post-birth variables were collected. A subsample of 994 children was clinically examined for DDE in 2017, using the modified DDE index, using the "full- mouth" (FM) protocol. After FM had been performed, a dataset was created. Two different partial protocols (PP) were simulated from FM data: "only buccal surfaces (BS)" and "incisive and molars only (IM)." Sensitivity, absolute and relative bias, and inflation factors were calculated. RESULTS: For any DDE, FM had prevalence of 40.8%. The prevalence of DDE was 38.8% and 36.0%, for BS and IM protocols, respectively. When tested for any DDE, PP "BS" and "IM" showed high sensitivity. The underestimation of the true prevalence did not exceed 6.9% for PP "BS" and 16.1% for PP "IM." All protocols showed similar magnitude of association with the selected risk factors. CONCLUSION: Both PP "BS" and "IM" can be used to estimate the prevalence of DDE in epidemiological studies. CLINICAL RELEVANCE: Oral health surveys now have the option of using PP to collect DDE prevalence and investigate their association with risk factors, being less time-consuming, expensive, and labor intensive.

Molar Incisor Hypomineralization in adolescents and adults and its association with facial profile and occlusion.

OBJECTIVES: To date, there are no data available in the scientific literature about the diagnosis of Molar Incisor Hypomineralization (MIH) in adults. We aimed to assess the MIH prevalence and clinical characteristics in adolescents and adults and its association with facial profile and occlusion. MATERIALS AND METHODS: In this cross-sectional study, permanent teeth were evaluated in 275 patients between the ages of 12 and 49 at a dental clinic, using intraoral photographs. A calibrated examiner classified enamel hypomineralization using the MIH index. Statistical analyses were performed using chi-square, Fisher's tests, and ordinal logistic regression. RESULTS: MIH was observed in 12.73% of all patients. The most commonly affected teeth were permanent molars, while incisors, premolars, and canines were less affected. MIH usually appears as demarcated opacities, with less than one-third of the tooth affected. There was no association between severe defects and facial profile and occlusion, but rather with the higher age of the participants. CONCLUSION: Enamel hypomineralization mainly affects the first and second permanent molars, but it could also be observed in the third molars, although it is not associated with the orthodontic characteristics investigated. CLINICAL RELEVANCE: This is the first study to highlight the prevalence of MIH in adults. This result showed the importance of other specialists beyond Pediatric Dentistry in the diagnosis of this defect. In addition, hypomineralization of other permanent teeth (canines, premolars, and second molars) has been described previously in other studies, but this is the first to identify MIH in third molars.

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.

Determination of dental caries, molar-incisor hypomineralization, and oral health-related quality of life in schoolchildren: A structural equation modeling approach.

BACKGROUND: Some oral conditions can have psychosocial consequences that affect children's daily life and well-being. AIM: To create a structural model for the determination of dental caries, molar-incisor hypomineralization (MIH), and the impact of these conditions and socioeconomic status on schoolchildren's oral health-related quality of life (OHRQoL). DESIGN: A representative cross-sectional study was conducted in Lavras, Brazil, with 1181 female and male schoolchildren 8-9 years of age. OHRQoL was measured using the Brazilian version of the CPQ8-10. Clinical examinations were performed by a calibrated dentist for the diagnosis of dental caries (WHO) and MIH (EAPD). Parents/caregivers answered questionnaires addressing the child's medical history and socioeconomic status. Data were analyzed using structural equation modeling. RESULTS: The model revealed that greater MIH severity (ß = .874; p < .001) and worse socioeconomic status (ß = -.060; p = .001) were associated with a greater number of teeth with caries experience. The higher the number of teeth with caries experience (ß = .160; p = .007) and worse socioeconomic status (ß = -.164; p < .001), the greater the negative impact on OHRQoL. CONCLUSION: The model created showed that dental caries and socioeconomic status had a direct negative impact on the OHRQoL of schoolchildren and MIH had an indirect impact mediated by the occurrence of caries experience.

Is there an association between molar incisor hypomineralization and developmental dental anomalies? A case-control study.

BACKGROUND: The aim of this study was to determine whether there is any association between molar incisor hypomineralization and developmental dental anomalies. METHODS: Two pediatric dentists evaluated panoramic radiographs of 429 children aged 8-14 years with molar incisor hypomineralization (study group) and 437 children without molar incisor hypomineralization (control group) in terms of developmental dental anomalies. Twelve different developmental dental anomalies were categorized into four types: size (microdontia, macrodontia); position (ectopic eruption of maxillary permanent first molars, infraocclusion of primary molars); shape (fusion, gemination, dilaceration, taurodontism, peg-shaped maxillary lateral incisors); and number (hypodontia, oligodontia, hyperdontia) anomalies. RESULTS: No significant difference was observed in the frequencies of developmental dental anomalies between the study and control groups in total, females, and males (p > 0.05). A statistically significant difference was found between the distribution of developmental size, position, shape, and number anomalies between the study and control groups (p = 0.024). The most common anomaly in both groups was hypodontia (6.3% and 5.9%, respectively). There was a significant difference between the study and control groups in terms of subtypes of shape anomaly in all children and females (p = 0.045 and p = 0.05, respectively). CONCLUSIONS: While a significant difference was observed between the distributions of types of developmental dental anomalies between individuals with and without molar incisor hypomineralization, there was no difference in terms of the frequency of developmental dental anomalies.

Molar-incisor hypomineralisation: Knowledge and perception of Syrian undergraduate and postgraduate dental students.

INTRODUCTION: Dentists' knowledge and expertise, especially in their early career, are primarily shaped during undergraduate studies. This cross-sectional study aimed to assess the knowledge and perception of Syrian under- and postgraduate students regarding diagnosing and managing molar-incisor hypomineralisation (MIH)-affected teeth. MATERIALS AND METHODS: Final-year dental students (FY-students), postgraduates in paediatric dentistry (PD-postgraduates) and postgraduates in other lines of specialty (OS-postgraduates) in all Syrian dental schools were invited to participate in an established web-based survey covering the knowledge and attitudes regarding the prevalence, aetiology, diagnosis and management of MIH. Data were analysed with descriptive statistics and Fisher's exact/chi-squared tests at 5%. RESULTS: In total, 1142 post- and undergraduate students from six public and five private dental schools in Syria participated in this study (867 FY-students, 74 PD-postgraduates and 201 OS-postgraduates). PD-postgraduates were found to present statistically significantly better knowledge regarding MIH compared with the two other groups. Only 19% of FY-students and 54% of OS-postgraduates reported themselves familiar with MIH (compared with 97% of PD-postgraduates). Similarly, 18% of FY-students and 27% of OS-postgraduates were capable of diagnosing MIH (compared with 81% of PD-postgraduates). Stainless-steel crowns and direct composite fillings were chosen as most suitable for treating MIH-affected molars from all responders. CONCLUSIONS: FY-students and even OS-postgraduates in Syria lack knowledge and confidence when confronted with MIH. The university curricula need to include more educational materials to equip the students with the necessary tools to manage MIH clinically.

Assessment of oral manifestations in pediatric patients with celiac disease in relation to marsh types.

BACKGROUND: To investigate the presence of molar-incisor hypoplasia and recurrent aphthous ulcers, the level of caries experience, and oral hygiene status, and to measure salivary flow rate, salivary buffer capacity, and salivary cariogenic microflora with Marsh types. MATERIAL AND METHODS: A single-blind, prospective clinical study with 62 pediatric patients diagnosed with celiac disease with 64 controls. Clinical identification of molar-incisor hypomineralization (MIH) was followed according to the European Academy of Pediatric Dentistry criteria. DMFS and dfs index were used for the caries experience of each child. The clinical diagnosis of RAU was present or not. Oral hygiene was surveyed by recording the OHI-S and the CRT® Bacteria and Buffer Test was used to examine the cariogenic microflora of each child. RESULTS: The prevalence of MIH was 61% and the number of recurrent aphthous ulcers were significantly higher in children with celiac disease. There was no statistically significant difference in the CD group, when DMFS, dfs, and MIH parameters were investigated according to dietary compliance. Higher dietary compliance resulted in better oral hygiene status. There was an inverse relationship between the duration of celiac diagnosis and the presence of MIH. A positive relation was found between the duration of the disease and the severity of MIH. In addition to the higher S. mutans counts, the salivary flow rate was very low in children with celiac disease, indicating a positive correlation between poor dietary compliance and poorer oral hygiene. CONCLUSIONS: In children, enamel defects and recurrent mucosal lesions may be a sign of celiac disease. Higher numbers of dental caries in permanent teeth of children with celiac disease may be related to Marsh 2 type. The pediatricians and/or pediatric gastroenterologists should refer the chin with celiac disease to the pediatric dentist for the accurate treatment of intraoral manifestations of the disease itself.

Prevalence and associated factors of enamel developmental defects among Nigerian children with perinatal HIV exposure.

To evaluate the prevalence and pattern of developmental defects of the enamel (DDE) and their risk factors among children born infected with Human Immunodeficiency Virus (HIV) and those born to HIV-infected mothers compared with their unexposed counterparts (i.e., children born to uninfected mothers). This was an analytic cross-sectional study evaluating the presence and pattern of distribution of DDE in three groups of school-aged children (age, 4-11 years) receiving care and treatment at a Nigerian tertiary hospital, comprising: (1) HIV-infected (HI) on antiretroviral therapy (ART) (n = 184), (2) HIV-exposed but uninfected (HEU) (n = 186) and (3) HIV-unexposed and uninfected (HUU) (n = 184). Data capture forms and questionnaires were used to record the children's medical and dental history based on clinical chart review and recall from their parents/guardians. Dental examinations were performed by calibrated dentists blinded to the study grouping. CD4+ (Cluster of Differentiation) T-cell counts were assayed for all participants. The diagnosis of DDE corresponded with the codes enumerated in the World Dental Federation's modified DDE Index. Analyses relied on comparative statistics to determine risk factors associated with DDE. A total of 103 participants distributed among the three groups presented with at least one form of DDE, which indicated a prevalence of 18.59%. The HI group had the highest frequency of DDE-affected teeth (4.36%), while that of the HEU and HUU groups were 2.73% and 2.05%, respectively. Overall, the most encountered DDE was code 1 (Demarcated Opacity), accounting for 30.93% of all codes. DDE codes 1, 4 and 6 showed significant associations with the HI and HEU groups in both dentitions (p < 0.05). We found no significant association DDE and either very low birth weight or preterm births. A marginal association with CD4+ lymphocyte count was observed in HI participants. DDE is prevalent in school-aged children, and HIV infection is a significant risk factor for hypoplasia, a common form of DDE. Our results were consistent with other research linking controlled HIV (with ART) to oral diseases and reinforce advocacies for public policies targeted at infants exposed/infected perinatally with HIV.

Are yellow-brownish opacities in hypomineralized teeth more prone to breakage than white-creamy ones? A systematic review.

OBJETIVE: To evaluate all the available evidence assessing if in hypomineralized teeth, yellow-brownish opacities are more prone to post-eruptive breakdown (PEB) compared to white-creamy opacities. MATERIALS AND METHODS: Observational studies that evaluated the occurrence of PEB in hypomineralized teeth were considered for inclusion. Electronic searches were performed up to January 2022 in MedLine, LILACS, BBO, Cochrane Library, Web of Science, Scopus, and EMBASE. Neither publication date nor language restrictions were imposed to the searches. Two researchers independently performed the study selection, data extraction, and quality assessment of the included studies according to the Newcastle-Ottawa Scale (NOS). Datasets from studies were grouped for narrative synthesis based on the severity of the PEB (enamel or dentin), type of tooth (molar or incisor), unit of analysis (subject or tooth or tooth surface), and follow-up period (in months). The certainty of evidence was evaluated using the GRADE approach. RESULTS: Nine studies were included, five cohort and three cross-sectional. All studies assessed the opacities and PEB by visual examination and diagnosed MIH according to EAPD criteria. In the cohort studies, considering all follow-up periods (ranging from 6 to 36 months), dark opacities fractured more than light opacities, at both enamel and enamel/dentin levels, and molars fractured more than incisors. In two out of three cross-sectional studies, dark opacities also fractured more than light opacities, but the deep of the PEB (enamel or dentin breakdown) or the type of tooth (molar or incisor) was not considered in the analysis. CONCLUSION: Although it seems plausible to state that darker demarcated opacities in MIH patients broke more often than light ones, based on this systematic review of the literature, the certainty of the available evidence about this association is still very low. CLINICAL RELEVANCE: More reliable and valid research is still necessary to support any future recommendation that MIH children who present yellow-brownish opacities should be monitored at shorter intervals compared to those who present only white-creamy opacities.

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

AIM: To evaluate the prevalence of HSPM worldwide on a child and a tooth level and investigate the influence of diagnostic criteria on the prevalence of HSPM. DESIGN: A comprehensive literature search was performed through MEDLINE/PubMed, Scopus, and Web of Science databases. The grey literature was also screened as were the reference lists of included studies. An adaptation of the Newcastle-Ottawa Scale was used to evaluate the quality of the studies. A meta-analysis was performed to determine the pooled prevalence of HSPM. RESULTS: The search strategy identified 1,988 articles, 487 were retrieved for full-text evaluation, and 37 studies were included in the meta-analysis (32 for child and 23 for tooth level prevalence), providing data from 26,805 individuals and 81,107 molars. The prevalence of HSPM was 6.8% (95% CI 4.98%-8.86%) on a child level and 4.08% on a tooth level (95% CI = 2.80%-5.59%). The diagnostic criteria used did not seem to influence the prevalence results (P > .05). The majority of the papers (75%) showed a low-to-moderate risk of bias. CONCLUSION: There was a broad variation in the prevalence reported that may be attributed to differences in the study population. The present meta-analysis showed a HSPM prevalence worldwide of 6.8% on a child level and 4.1% on a tooth level.

Knowledge, perception, and clinical experiences on molar incisor hypomineralization amongst Portuguese dentists.

AIM: Molar incisor hypomineralization (MIH) is a prevalent oral health condition whose knowledge by dentists is key to the best clinical outcome. This study aimed to evaluate the knowledge, perceptions and clinical experiences of MIH among Portuguese dentists. METHODS: A cross-sectional structured questionnaire was distributed nationally through a web-based survey platform. Data concerning demographic variables, years of experience, dental specialty, MIH prevalence, diagnosis, severity, training demands and clinical management of MIH were collected. We calculated a knowledge score (KS), and compared data between Pediatric Dentists (PDs), General Dental Practitioners (GDPs) and other dental specialties (ODS). RESULTS: Overall, 2.2% of Portuguese dentists (n = 257) answered the questionnaire. Most participants reported having identified MIH in their practice (82.5%), with PD reporting the prevalence appeared to have increased, and practically all (91.7%) considered it a public health problem. Resin composite was often the used material to restore MIH teeth (56.0%), however PDs indicated glass ionomer cements as the preferred and preformed crowns a better option. The average KS on MIH was 41.3 (± 5.7), with GDPs having a similar score than PDs. Most respondents (94.9%) reported a lack of information about MIH and were willing to receive appropriate clinical training. CONCLUSIONS: The average knowledge on MIH was considered low among Portuguese dentists. Respondents perceived an increased incidence of MIH, despite the lack of prevalence data in Portugal. The material of choice was Glass Ionomer and performed crowns, by PDs, while GDPs and ODS reported poor confidence to manage MIH. These results may serve future programs to increase knowledge, perceptions and clinical experiences towards MIH.

Prevalence of Molar Incisor Hypomineralization in over 30,000 Schoolchildren in Switzerland.

OBJECTIVES: To quantify the prevalence of Molar Incisor Hypomineralization (MIH) in the canton of Geneva, Switzerland. STUDY DESIGN: Thirty-eight dentists of the state school dental services were trained to detect and classify MIH cases. All children (32,142) from age 4 to 12 were examined during the annual dental screening offered by the state. Cases were scored as mild, moderate or severe. RESULTS: The prevalence of hypomineralizations was found to be 7.45% when all hypomineralized teeth were taken into consideration. MIH cases were found to be at 6.6%. Out of the MIH cases, 51% scored as mild, 36% as moderate and 13% as severe. CONCLUSION: The mean prevalence of MIH in Geneva school children was found to be 6.6%. This seems to be lower than the European and the global average. However, with almost half cases being moderate or severe, asserting a proper management protocol is necessary.