Cdc42 deletion yielded enamel defects by disrupting mitochondria and producing reactive oxygen species in dental epithelium.

Developmental defects of enamel are common due to genetic and environmental factors before and after birth. Cdc42, a Rho family small GTPase, regulates prenatal tooth development in mice. However, its role in postnatal tooth development, especially enamel formation, remains elusive. Here, we investigated Cdc42 functions in mouse enamel development and tooth repair after birth. Cdc42 showed highly dynamic temporospatial patterns in the developing incisors, with robust expression in ameloblast and odontoblast layers. Strikingly, epithelium-specific Cdc42 deletion resulted in enamel defects in incisors. Ameloblast differentiation was inhibited, and hypomineralization of enamel was observed upon epithelial Cdc42 deletion. Proteomic analysis showed that abnormal mitochondrial components, phosphotransferase activity, and ion channel regulator activity occurred in the Cdc42 mutant dental epithelium. Reactive oxygen species accumulation was detected in the mutant mice, suggesting that abnormal oxidative stress occurred after Cdc42 depletion. Moreover, Cdc42 mutant mice showed delayed tooth repair and generated less calcified enamel. Mitochondrial dysfunction and abnormal oxygen consumption were evidenced by reduced Apool and Timm8a1 expression, increased Atp5j2 levels, and reactive oxygen species overproduction in the mutant repair epithelium. Epithelium-specific Cdc42 deletion attenuated ERK1/2 signaling in the labial cervical loop. Aberrant Sox2 expression in the mutant labial cervical loop after clipping might lead to delayed tooth repair. These findings suggested that mitochondrial dysfunction, up-regulated oxidative stress, and abnormal ion channel activity may be among multiple factors responsible for the observed enamel defects in Cdc42 mutant incisors. Overall, Cdc42 exerts multidimensional and pivotal roles in enamel development and is particularly required for ameloblast differentiation and enamel matrix formation.

Oral health and related outcomes in children and adolescents with cystic fibrosis: a scoping review.

PURPOSE: Good oral health is important for children and adolescents with cystic fibrosis (CF). The purpose of this scoping review is to describe the existing evidence base regarding oral health in children and adolescents with CF and provide recommendations for future research. METHODS: Using a scoping review framework, a comprehensive search was undertaken using medline, embase, and PubMed. The search strategy included broad terms relating to CF, oral health, and children and adolescents and included only papers written in English. RESULTS: 61 articles were included. Topics investigated included dental caries, enamel defects, periodontal health, dental staining, oral health related quality of life, dental management, and dental development of children and adolescents with CF. CONCLUSION: Dental outcomes of children and adolescents with CF differ from the healthy population. The current literature describing dental health in children and adolescents with CF includes predominately descriptive analyses. A shift to hypothesis-based studies to explore causal relationships that explain the differences in dental outcomes seen in the CF population offers an opportunity to better understand the problems faced by children and adolescents with CF. Research that actively engages stakeholders, including children and adolescents with CF and their families will enable evidence-based recommendations to improve their oral health.

Celiac Disease-Related Enamel Defects: A Systematic Review.

INTRODUCTION: This systematic review aims to elucidate the intricate correlation between celiac disease (CD) and dental enamel defects (DED), exploring pathophysiological mechanisms, oral health implications, and a dentist's role in early diagnosis. MATERIALS AND METHODS: Following PRISMA guidelines, a comprehensive search from 1 January 2013 to 1 January 2024 across PubMed, Cochrane Library, Scopus, and Web of Science identified 153 publications. After exclusions, 18 studies met the inclusion criteria for qualitative analysis. Inclusion criteria involved study types (RCTs, RCCTs, case series), human participants, English language, and full-text available. RESULTS: The search yielded 153 publications, with 18 studies meeting the inclusion criteria for qualitative analysis. Notable findings include a high prevalence of DED in CD patients, ranging from 50 to 94.1%. Symmetrical and chronological defects, according to Aine's classification, were predominant, and significant associations were observed between CD severity and enamel defect extent. CONCLUSIONS: The early recognition of oral lesions, particularly through Aine's classification, may signal potential CD even in the absence of gastrointestinal symptoms. Correlations between CD and dental health conditions like molar incisor hypomineralization (MIH) emphasize the dentist's crucial role in early diagnosis. Collaboration between dentists and gastroenterologists is essential for effective monitoring and management. This review consolidates current knowledge, laying the groundwork for future research and promoting interdisciplinary collaboration for improved CD-related oral health outcomes. Further large-scale prospective research is recommended to deepen our understanding of these issues.

Dental caries in children and vitamin D deficiency: a narrative review.

Dental caries represents one of the most prevalent health problems in childhood. Numerous studies have assessed that vitamin D deficiency is highly related to dental caries in primary and permanent teeth in children. The aim of this study is to elaborate a narrative review about proposed mechanisms by which vitamin D deficiency interacts with dental caries process in children. Vitamin D deficiency during pregnancy may cause intrauterine enamel defects, and through childhood is accompanied by insufficient activity of antibacterial peptides, decreased saliva secretion, and a low level of calcium in saliva.  Conclusion: In conclusion, vitamin D deficiency would increase the risk of caries in the primary and/or permanent dentition. Relationship between vitamin D deficiency and dental caries is evident enough for vitamin D deficiency to be considered as a risk factor for dental caries in children. Optimal levels of vitamin D throughout pregnancy and childhood may be considered an additional preventive measure for dental caries in the primary and permanent dentition.

Association between molar hypomineralization, genes involved in enamel development, and medication in early childhood: A preliminary study.

BACKGROUND: Molar hypomineralization (MH) is defined as a multifactorial condition, and thus, its presence may be defined by interactions between environmental and genetic factors. AIM: To evaluate the association between MH, genes involved in enamel development, and the use of medication during pregnancy in early childhood. DESIGN: One hundred and eighteen children, 54 with and 64 without MH, were studied. The data collected included demographics, socioeconomic data, and the medical history of mothers and children. Genomic DNA was collected from saliva. Genetic polymorphisms in ameloblastin (AMBN; rs4694075), enamelin (ENAM; rs3796704, rs7664896), and kallikrein (KLK4; rs2235091) were evaluated. These genes were analyzed by real-time polymerase chain reaction using TaqMan chemistry. The software PLINK was used to compare allele and genotype distributions of the groups and to assess the interaction between environmental variables and genotypes (p < .05). RESULTS: The variant allele KLK4 rs2235091 was associated with MH in some children (odds ratio [OR]: 3.75; 95% confidence interval [CI] = 1.65-7.81; p = .001). Taking medications in the first 4 years of life was also associated with MH (OR: 2.94; 95% CI = 1.02-6.04; p = .041) and specifically in association with polymorphisms in ENAM, AMBN, and KLK4 (p < .05). The use of medications during pregnancy was not associated with MH (OR: 1.37; 95% CI = 0.593-3.18; p = .458). CONCLUSION: The results of this study suggest that taking medication in the postnatal period appears to contribute to the etiology of MH in some evaluated children. There may be a possible genetic influence of polymorphisms in the KLK4 gene with this condition.

Prenatal, neonatal and postnatal factors and the developmental defects of dental enamel / Fatores pré-natais, neonatais e pós-natais e defeitos de desenvolvimento do esmalte dentário

ABSTRACT Objective: To estimate the prevalence of developmental defects in dental enamel and its possible association with prenatal, neonatal and postnatal conditions in six-year-old schoolchildren in a southern Brazilian municipality. Methods: A cross-sectional study was conducted involving 655 six-year-old schoolchildren. Sociodemographic and health data were collected through interviews with mothers and children's oral examinations at schools. Multivariate analyses were performed using Poisson regression with robust estimator. Results: The prevalence of developmental defects of enamel was 44.0%. Demarcated opacities were the most prevalent, followed by diffuse opacities. Late pregnancy, maternal schooling less than eight years, female gender and child's white skin color were independently associated with the prevalence of demarcated opacities. Conclusions: The prevalence of developmental defects in dental enamel was 44.0%. Late pregnancy, maternal schooling less than eight years, female gender and child's white skin color were associated with the prevalences.

RESUMO Objetivo: Estimar a prevalência de defeitos de desenvolvimento do esmalte dentário e sua possível associação com fatores pré-natais, neonatais e pós-natais em escolares de seis anos de idade em um município do sul do Brasil. Métodos: Foi conduzido um estudo transversal envolvendo 655 escolares de seis anos de idade. Os dados sociodemográficos e de saúde foram coletados por meio de entrevistas com as mães e exames bucais das crianças nas escolas. As análises multivariadas foram realizadas por meio de regressão de Poisson com estimador robusto. Resultados: A prevalência de defeitos de desenvolvimento do esmalte foi de 44,0%. As opacidades demarcadas foram as mais prevalentes, seguidas das difusas. Gravidez tardia, escolaridade materna inferior a oito anos, sexo feminino e cor da pele branca da criança foram independentemente associados à prevalência de opacidades demarcadas. Conclusões: A prevalência de defeitos de desenvolvimento do esmalte dentário foi de 44,0%. Gravidez tardia, escolaridade materna inferior a oito anos de estudo, sexo feminino e cor da pele branca da criança estiveram associados às prevalências.

Recessive COL17A1 Mutations and a Dominant LAMB3 Mutation Cause Hypoplastic Amelogenesis Imperfecta.

Hereditary conditions that affect tooth enamel in quantity and/or quality are called amelogenesis imperfecta (AI). AI can occur as an isolated condition or as a symptom of a syndrome. An OMIM search with the term "AI" yielded 79 result entries. Mutations in the same gene cause syndromic or non-syndromic AI, depending on the nature of the mutations. In this study, we recruited two AI families and performed mutational analysis using whole-exome sequencing. The proband of family 1, with hypoplastic pitted AI and mild localized atopic dermatitis, had compound heterozygous COL17A1 mutations (paternal NM_000494.4: c.3598G>T, p.Asp1200Tyr and maternal c.1700G>A, p.Gly567Glu). The proband of family 2, with hypoplastic pitted AI and Jervell and Lange-Nielsen syndrome, had a recurrent LAMB3 mutation (NM_000228.3: c.3463_3475del, p.(Glu1155Thrfs*51)) in addition to compound heterozygous mutations in the KCNQ1 gene.

Asthma medication and risk of dental diseases in children - A prospective cohort study.

BACKGROUND: Dental caries and enamel defects are the main causes of poor dental health in children, with a substantial impact on their well-being. Use of inhaled asthma medication is a suspected risk factor, but there is a lack of prospective studies investigating this and other prenatal and early life risk factors. METHODS: Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort (COPSAC2010 ) consists of 700 women who were recruited at 24 weeks of pregnancy. 588 of their children participated in a dental examination at 6 years of age (84%) at the COPSAC2010 research unit. Caries was defined as decayed, missing, or filled surfaces. Enamel defect was defined as demarcated opacity, post-eruptive enamel breakdown, and/or atypical restoration on at least one molar. Caries and enamel defects were assessed in both deciduous and permanent dentitions. RESULTS: We found no associations between inhaled corticosteroids or ß2 -agonists or asthma symptoms in early childhood and the risk of caries or enamel defects by 6 years of age. Furthermore, we found no strong pre-, peri-, or postnatal risk factors for dental diseases at 6 years, except from nominally significant associations between antibiotic use in pregnancy (OR = 1.25, [1.01-1.54]), maternal education level (OR = 1.57, [1.01-2.45]), having a dog at home (OR = 0.50, [0.27-0.93]), and risk of enamel defects. CONCLUSIONS: Use of inhaled corticosteroids, ß2 -agonists, or asthma symptoms in the first 6 years of life were not associated with the development of caries or enamel defects. This finding is reassuring for parents and physicians prescribing asthma medication for young children.

Investigation on the effects of long-term antibiotic therapy in sickle cell disease associated with molar-incisor hypomineralisation-a pilot study.

The term Molar-Incisor Hypomineralisation (MIH) is used to describe hypomineralised defects of systemic origin that affect at least one of the first permanent molars and often involves the permanent incisors. Antibiotic therapy during amelogenesis may be associated with enamel hypomineralisation. By examining children with Sickle Cell Disease (SCD), who take prophylactic antibiotics daily from birth until age five, it may be possible to determine if there is an increased prevalence of MIH in this population. The aim of this study was to determine the effect of long-term antibiotic use on the prevalence and severity of MIH in children with SCD. In a prospective cohort pilot study over a period of seven months, children aged 7-17 years, with SCD at Boston Children's Hospital (n = 18) were examined for MIH. Information regarding peri-natal concerns, incidence of illness and antibiotic use were also collected. The results were compared to a group of control patients (n = 63) for prevalence and severity of MIH using Fisher's exact test. The patients with SCD, 4/18 (22%) taking daily antibiotics did not show a statistically significant greater prevalence of MIH compared to the control group, 24/63 (38%). There was no correlation between MIH and pneumonia, asthma, fever, flu, otitis media, breastfeeding, gender and birth weight. However, an association was noted between premature birth and MIH (p ≤ 0.05). No correlation was found between long-term antibiotic use and higher prevalence of MIH in the SCD group compared to the control group. However, MIH may be more severe in those with a history of long-term antibiotics.

Prevalence, Severity and Associated Risk Indicators of Molar Incisor Hypomineralization amongst 8-13-year-old Children of Vadodara District Gujarat: A Cross-sectional Study.

Context: Molar incisor hypomineralization (MIH) is an emerging clinical problem as the affected tooth is prone to dental caries with the lapse of time. Aims: To assess the prevalence, severity, and associated risk indicators of MIH amongst 8-13 years of children of Vadodara District, Gujarat, India. Materials and methods: A cross-sectional study with a sample size of 3,000 government schoolchildren. A total of 1,500 children each from urban and rural areas were randomly selected and examined. Only permanent incisors and first molars were examined. MIH was diagnosed clinically based on the diagnostic criteria established by the European Academy of Paediatric Dentistry (EAPD), 2003. To check the relation between the two variables-Pearson's chi-squared test was applied. Fisher's exact test was applied when less than five expected values were found. Results: A total of 286 children (9.6 %) had MIH, with 189 (rural) and 97 (urban) children. MIH was significantly higher in the rural population as compared to the urban. In the rural area, the cause was found to be a child suffering from an illness (>15 days) which was 35.98%, and in the urban area was due to prolonged use of antibiotics before 4 years of age, which was 28.87%. Conclusion: The overall prevalence rate of MIH among the screened children between the age-group 8 and 13 was found to be 9.6%. Males were more affected. The severity of MIH was more in molars compared to incisors and more in children of rural areas. Clinical significance: Protocol for early diagnosis and follow-up to access the squeal of breakdown should be undertaken along with parents and health workers. How to cite this article: Shah VU, Dave BH, Chari DN, et al. Prevalence, Severity and Associated Risk Indicators of Molar Incisor Hypomineralization amongst 8-13-year-old Children of Vadodara District Gujarat: A Cross-sectional Study. Int J Clin Pediatr Dent 2023;16(2):280-286.

The Evaluation of Oral Health Condition and Oral and Dental Care in Children with Congenital Heart Disease.

Objective: Congenital heart disease (CHD) plays a key role in oral and dental health regarding its own impacts on teeth (i.e., enamel hypoplasia), infective endocarditis and choice of dental treatment. The purpose of this study's comparing the oral and dental health status in children with or without CHD is to contribute to the literature by determining the effects of CHD on oral and dental health. Material and Methods: The present study was conducted using a descriptive and correlational design and consisted of 581 children aged between 6 months and 18 years who were healthy (n = 364) or experienced CHD (n = 217). CHD-impacted children were classified according to their shunt and stenosis and then their saturation values were noted. In the intraoral examination, caries data (dmft/DMFT, PUFA/pufa), oral hygiene (OHI-S) and enamel defect (DDE) indices were recorded. Statistical analyses were performed using SPSS 26.0 at a significance level of 0.05. Results: In our study, caries index scores of children with or without CHD in primary or permanent dentition were found to be similar. The mean OHI-S index (p < 0.001) and gingivitis findings (p = 0.047) of children with CHD had a higher prevalence than the healthy ones. The incidence of enamel defects was determined as 16.5% in CHD-affected children whereas an incidence rate of 4.7% was observed in healthy children. The mean saturation value of the participants with enamel defects (89 ± 8.9) was observed to be significantly lower (p = 0.03) than the patients with no enamel defects (95 ± 4.2). Conclusions: Whereas the caries index scores of CHD-affected children with a history of hypoxia in primary and permanent dentition were found to be similar to the healthy ones, children with CHD were observed to be more prone to enamel defects and periodontal diseases. Furthermore, considering the risk of infective endocarditis resulting from existing carious lesions and periodontal problems, it is highly important for pediatric cardiologists, pediatricians and pediatric dentists to collaborate in a multidisciplinary manner.

Oral health-related quality of life and oral manifestations of Syrian children with congenital heart disease: a case-control study.

BACKGROUND: There was an immense need for studies evaluating the oral health status of Syrian children with congenital heart disease (CHD) and its impact on their quality of life. No contemporary data are available. The objective of this study was to investigate oral manifestations and oral health-related quality of life (OHRQoL) of children with CHD and compare them with healthy controls aged 4-12 years. METHODS: A case-control study was undertaken. A total of 200 patients with CHD and 100 healthy children belonging to the same patient's family were included. Decayed, missed, and filled permanent teeth index (DMFT) and decayed, missed, and filled primary teeth index (dmft), Oral Hygiene Index (OHI), Papillary Marginal Gingivitis Index (PMGI), and dental abnormalities were recorded. The Arabic version of the Child Oral Health-Related Quality of Life Questionnaire (COHRQoL, 36-item) which was divided into 4 different domains (Oral Symptoms, Functional Limitations, Emotional Well-Being, Social Well-Being) were studied. Chi-square test and independent- t-test were used to perform statistical analysis. RESULTS: CHD patients experienced more periodontitis, dental caries, poor oral health, and enamel defects. The dmft mean was significantly higher in CHD patients than in healthy children (5.245 vs. 2.660, P < 0.05). No significant difference was found between patients and controls in the DMFT Mean (P = 0.731). There was a significant difference between CHD patients and healthy children in the mean of the OHI (5.954 vs. 1.871, P < 0.05), and PMGI (1.689 vs. 1.170, P < 0.05). CHD patients have significantly higher enamel opacities (8% vs. 2%) and hypocalcification (10.5% vs. 2%) than controls. Also, the 4 COHRQoL domains, showed significant differences between CHD children and controls. CONCLUSIONS: Evidence about the oral health and COHRQoL of children with CHD was provided. Further preventive measures are still required to improve the health and quality of life of this vulnerable group of children.

Crystalline analysis of dental enamel by X-Ray diffraction on pediatric patients with chronic kidney disease.

This study aimed to analyze the crystalline structure of dental enamel in pediatric patients with chronic kidney disease (CKD) by X-ray diffraction (XRD). The six tested samples had a mineral composition similar to hydroxyapatite, according to sheet JCPDS(Joint Committee on Powder Diffraction Standards) card #09-0432, which is normally found in dentine, and presented a lower amount of whitlockites (Ca, Mg)3(PO4)2. Pattern phases showed an increase in organic matter and a decrease in inorganic matter. At an interval of approximately 2θ = 15.7° to 27.2°, amorphous organic matter corresponding to hydrated glucose was found. The hydroxyapatite patterns in this study differed from that of dental enamel found on permanent teeth.

Dental Manifestations and Celiac Disease-An Overview.

This review summarizes recent investigations on dental manifestations in celiac disease. Particular attention is paid to delayed dental eruption and maturity, dental enamel defects, molar incisor hypomineralization, dental caries, dental plaque, and periodontitis. Most studies confirmed a higher frequency of delayed dental eruption and maturation in children and dental enamel defects in children and adults with celiac disease compared to healthy individuals. The malabsorption of various micronutrients, especially calcium and vitamin D, as well as immunity, is considered the main cause of these conditions. An early diagnosis of celiac disease and introducing a gluten-free diet might prevent the development of these conditions. Otherwise, the damage has already been established, and it is irreversible. Dentists can play an important role in identifying people who may have unrecognized celiac disease and may help prevent its progress and long-term complications. Investigations on dental caries, plaque, and periodontitis in celiac disease are rare and inconsistent; these complaints need further examination.

Novel WDR72 Mutations Causing Hypomaturation Amelogenesis Imperfecta.

Amelogenesis imperfecta (AI) is a heterogeneous collection of hereditary enamel defects. The affected enamel can be classified as hypoplastic, hypomaturation, or hypocalcified in form. A better understanding of normal amelogenesis and improvements in our ability to diagnose AI through genetic testing can be realized through more complete knowledge of the genes and disease-causing variants that cause AI. In this study, mutational analysis was performed with whole exome sequencing (WES) to identify genetic etiology underlying the hypomaturation AI condition in affected families. Mutational analyses identified biallelic WDR72 mutations in four hypomaturation AI families. Novel mutations include a homozygous deletion and insertion mutation (NM_182758.4: c.2680_2699delinsACTATAGTT, p.(Ser894Thrfs*15)), compound heterozygous mutations (paternal c.2332dupA, p.(Met778Asnfs*4)) and (maternal c.1287_1289del, p.(Ile430del)) and a homozygous 3694 bp deletion that includes exon 14 (NG_017034.2:g.96472_100165del). A homozygous recurrent mutation variant (c.1467_1468delAT, p.(Val491Aspfs*8)) was also identified. Current ideas on WDR72 structure and function are discussed. These cases expand the mutational spectrum of WDR72 mutations causing hypomaturation AI and improve the possibility of genetic testing to accurately diagnose AI caused by WDR72 defects.

Dietary and metabolic effects on the oral status of patients with phenylketonuria: a nation-based cross-sectional study.

OBJECTIVES: The aim of this study was to compare the prevalence of oral diseases (caries, periodontal disease, enamel defects) between patients with phenylketonuria (PKU), their siblings, and a matched control group. MATERIALS AND METHODS: A total of 109 patients with PKU, 14 siblings of PKU patients, and 100 healthy individuals aged 6 to 68 years were recruited. All participants completed a questionnaire based on their health status. The patients' decayed/missing/filled teeth index (dmft/DMFT), gingival bleeding index (GBI), plaque control record (PCR), periodontal screening and recording index (PSR), and developmental enamel defects index (DDE) were recorded. Descriptive statistics and regression modeling were used to examine potential associations between the exposure and the outcomes of interest. RESULTS: Patients with PKU had 1.6 times more caries (95% confidence interval (CI) 1.22 to 2.20; p = 0.001), seven times more enamel defects (95% CI 3.94 to 14.21; p < 0.001), and four times higher PSR values (95% CI 2.26 to 7.15; p < 0.001) than the control group. The siblings had significantly fewer enamel defects but no significant differences in caries and periodontal parameters compared to the PKU patients. CONCLUSIONS: The results showed a higher risk for the development of caries, periodontitis, and enamel defects in PKU patients. CLINICAL RELEVANCE: Implementation of preventive measures and regular dental care is necessary for patients with PKU.

Digital restorative workflows for developmental dental defects in young patients: A case series.

BACKGROUND: Digital technology is rapidly changing the provision of oral health care, although its adoption for the oral health care of young patients has lagged. The authors describe digitally supported treatment approaches for managing treatment of developmental dental defects in the early permanent dentition. CASE DESCRIPTION: Four adolescent patients with amelogenesis imperfecta received transitional anterior restorations for esthetic and functional rehabilitation using a variety of digital workflows. Combinations of restoration type, materials, and fabrication methods were selected to meet the needs of each patient on the basis of their specific amelogenesis imperfecta phenotype and chief symptoms. These cases highlight the application of digital technology in pediatric and adolescent dentistry for managing the treatment of developmental dental defects. PRACTICAL IMPLICATIONS: Digitally supported restorative approaches, as described in this report, offer broad applicability of materials and techniques directed at treating the complex restorative needs of young patients in the transitional and early permanent dentition.

Enamel defects of Axenfeld-Rieger syndrome and the role of PITX2 in its pathogenesis.

OBJECTIVES: To investigate the detailed ultrastructural patterns of dental abnormalities affected by Axenfeld-Rieger syndrome (ARS) with a heterozygous microdeletion involving paired-like homeodomain 2 (PITX2) and explored the underlying molecular mechanisms driving enamel defects. SUBJECTS AND METHODS: Sanger sequencing, genomic quantitative PCR analysis, and chromosomal microarray analysis (CMA) were used to screen the disease-causing mutation in one ARS proband. An exfoliated tooth from an ARS patient was analyzed with scanning electron microscopy and micro-computerized tomography. A stable Pitx2 knockdown cell line was generated to simulate PITX2 haploinsufficiency. Cell proliferation and ameloblast differentiation were analyzed, and the role of the Wnt/ß-catenin pathway in proliferation of ameloblast precursor cells was investigated. RESULTS: An approximately 0.216 Mb novel deletion encompassing PITX2 was identified. The affected tooth displayed a thinner and broken layer of enamel and abnormal enamel biomineralization. PITX2 downregulation inhibited the proliferation and differentiation of inner enamel epithelial cells, and LiCl stifmulation partially reversed the proliferation ability after Pitx2 knockdown. CONCLUSIONS: Enamel formation is disturbed in some patients with ARS. Pitx2 knockdown can influence the proliferation and ameloblast differentiation of inner enamel epithelial cells, and PITX2 may regulate cell proliferation via Wnt/ß-catenin signaling pathway.

Clinical status and assessment of caries on first permanent molars in a group of 6- to 13-year-old Tunisian school children.

AIM: The present survey aimed to highlight the clinical status of first permanent molars (FPMs) among a group of children aged between 6 and 13 years in public primary schools in Tunisia and to determine the association between FPMs' dental caries, gingival bleeding, malocclusion, dental fluorosis, and enamel defects. MATERIALS AND METHODS: The survey involved a cross-sectional study based on a dental examination conducted in public primary schools in Monastir Tunisia. A dental caries assessment was performed on FPMs using the International Caries Detection and Assessment System classification; the number of carious lesions in permanent and temporary dentition was established using the decayed/missing/filled teeth (DMFT) index. The Gingival Index and the Dental Aesthetic Index were used to determine the occurrence of gingival bleeding and malocclusions. Dean's index and the modified Development Defects of Enamel index were used to define the enamel defects. The χ2 test was used to assess the difference between more than two groups, and the level of statistical significance was set at .05%. RESULTS: A total of 545 children and 2080 FPMs were examined. The prevalence of dental caries in FPMs was recorded to be 35.8%. The overall mean DMFT index of the study population was 1.62 and the mean DMFT index was 1.41. The proportion of carious FPMs increased significantly with the age of the children (p < .05). The mandibular first permanent molar presented higher caries prevalence than its maxillary counterpart (p < .05). The presence of surfaces affected by molar incisor hypomineralization was recorded in 4.3% and the presence of surfaces affected by fluorosis was recorded in 4.6% of FPMs. No association was reported between FPMs' dental caries, gingival bleeding, malocclusion, and enamel defects (p > .05). CONCLUSION: Although the prevalence of caries in FPMs was considered moderate, health promotion programs should be implemented on a large scale to decrease the prevalence of dental caries among school children.

O impacto dos defeitos de esmalte no planejamento ortodôntico / The impact of enamel defects on orthodontic planning

Resumo A decisão pela extração de dentes permanentes para a solução de problemas ortodônticos considera, além da extração em si, outros fatores, dentre eles, as características clínicas do esmalte dos dentes a serem extraídos. O objetivo deste artigo foi apresentar como a presença de defeitos de esmalte dentário (DDE) influenciou na tomada de decisão e modificou o plano de tratamento ortodôntico proposto para o paciente. A severidade do defeito, o número de dentes afetados e a presença e complexidade de má oclusão são fatores que influenciaram na definição do plano de tratamento. Quanto mais grave os defeitos e mais complexa a má oclusão, maior a dificuldade no planejamento do tratamento e, em muitos casos, é indicado incorporar a contribuição de vários especialistas na tomada de decisões. Foi possível demonstrar que o tratamento da má oclusão associada a DDE com a exodontia dos dentes mais severamente afetados apresentou resultados estético e funcional adequados. Concluiu-se que um tratamento bem-sucedido da má oclusão com resultado estético dentofacial adequado, saudável e funcional, requer a compreensão da inter-relação entre os componentes estruturais bucais, oclusão dentária e estética facial.(AU)

Abstract The decision to extract permanent teeth to solve orthodontic problems considers, in addition to the extraction itself, other factors, and among them are the clinical characteristics of the enamel of the teeth to be extracted. The objective of this article was to present how the presence of dental enamel defects (DED) influenced decision-making and modified the proposed orthodontic treatment plan for the patient. The severity of the defect, the number of affected teeth and the presence and complexity of the malocclusion are factors that influenced the definition of the treatment plan. The more severe the defects and the more complex the malocclusion, the greater the difficulty in planning the treatment and, in many cases, it is indicated to incorporate the contribution of several specialists in the decision-making process. It was possible to demonstrate that the treatment of malocclusion associated with DED with the extraction of the most severely affected teeth, presented adequate aesthetic and functional results. It is concluded that a successful treatment of malocclusion with adequate, healthy, and functional dentofacial aesthetic results, requires understanding the interrelationship between oral structural components, dental occlusion and facial aesthetics. (AU)