Enamel Hypomineralization Research Articles

Enamel Hypomineralization: Prevalence, Defect Characteristics in Primary Dentition in a Northern Indian Region.

No data is available on hypomineralization in the full complement of primary dentition. To report on the prevalence and clinical presentation of enamel hypomineralization (EH) in the primary dentition. A cross-sectional observational study with a random sample of 948, 4-6-year-old schoolchildren of Gautam Buddh Nagar, Uttar Pradesh, India, was conducted after approval from the Institutional Ethics Committee. European Academy of Paediatric Dentistry (EAPD) (2003) criteria were employed to score EH in all primary teeth. A single experienced examiner conducted an entire clinical examination of the study population. Data were expressed as the prevalence, type, extent, and distribution. Further analyses were conducted to compare the prevalence and distribution of different types of lesions in affected subjects using student t-tests and analysis of variance (ANOVA). An overall prevalence of 7.51% (71/948) was reported. A total of 2.75 ± 1.735 teeth/subject were reported to be affected. The most common lesion was creamy white opacity (p = 0.002), while posteruptive breakdown (PEB) was observed in 40.85% (29/71) of affected subjects. The prevalence of EH in primary dentition was 7.51%. Further studies mapping the prevalence as well as possible links with molar incisor hypomineralization (MIH) in other geographical locations of the world are required. Mittal N, Gupta N, Goyal A. Enamel Hypomineralization: Prevalence, Defect Characteristics in Primary Dentition in a Northern Indian Region. Int J Clin Pediatr Dent 2024;17(S-1):S67-S72.

The Impact of Vitamin Deficiencies on Oral Manifestations in Children.

Vitamins play a vital role in human health, particularly in the development and maintenance of oral health in children. These nutrients are broadly categorized into fat-soluble and water-soluble types, crucial for children's well-being. The objective of this study is to investigate the impact of vitamin deficiencies on the oral health of children, focusing on how these deficiencies contribute to various oral health issues and determining the relationship between specific vitamin shortages and oral diseases. Findings indicate that shortages in vitamins A and D lead to enamel issues and a higher susceptibility to dental diseases, vitamin E assists in treating oral mucositis, and vitamin K is essential for blood clotting in dental surgeries. Deficits in B-complex and vitamin C result in enamel hypomineralization and soft tissue ailments, including aphthous stomatitis and gingival petechiae. Additionally, a lack of vitamin B7 compromises the immune response, increasing oral candidiasis risk. Therefore, vitamin deficiencies markedly affect children's oral health, highlighting the need for joint efforts between dental professionals and caregivers for effective pediatric care. Addressing vitamin deficiencies through supplementation and tailored dental care emphasizes the significance of nutritional health in children's overall and dental well-being, advocating for a collaborative approach to achieve optimal health outcomes.

Regenerative Endodontic Procedures in Immature Teeth Affected by Regional Odontodysplasia

IntroductionRegional odontodysplasia (ROD) is a rare developmental disorder characterized by hypo-mineralization and hypoplasia of enamel and dentin. Symptoms include poorly developed tooth buds, delayed eruption of permanent teeth in affected quadrants, and ghost teeth. The affected teeth often become necrotic due to abnormal enamel and dentin development, making them susceptible to caries and infection. The aim of this case report is to describe the treatment of ROD through pulp revascularization. Case reportA 13-year-old girl was referred for endodontic treatment. The mandibular left incisors and first premolar, which were affected by regional odontodysplasia, lost their vitality because of the impaired structure of the enamel. Due to the teeth's early developmental stage, a regenerative endodontic treatment was attempted. All 3 teeth were treated using the same protocol following the AAE guidelines. After 4 weeks, treatment of the premolar was completed, whereas the incisor teeth remained symptomatic and were and therefore, intracanal dressing with calcium hydroxide was repeated and left in place for 5 months. Finally, the regenerative procedure was completed, and the crowns were restored. The patient was scheduled for follow-up examinations after 6 months, and then yearly for the next 3 years. After 1 year, the periapical lesion around the central incisor and premolar had resolved, the lesion around the apex of the lateral incisor was healing, and the roots had continued to develop. After 3 years, complete healing and pulp canal obliteration were observed in the central incisor and in the premolar. However, the root of the lateral incisor tooth was split, and it was recommended to extract this tooth. ConclusionThe positive outcomes of regenerative endodontics in the central incisor and premolar suggest that revascularization of the pulp may be optional for the treatment of immature necrotic teeth affected by developmental disorders, such as ROD, amelogenesis imperfecta, or dentinogenesis imperfecta.

Potential risk of dental fluorosis associated with different baby formulas and water brands marketed in Spain.

Despite efforts to promote breastfeeding, many babies aged <6 months receive only baby formula reconstituted with bottled water. The intake of high levels of fluoride during amelogenesis has been associated with hypomineralization of the tooth enamel, with aesthetic and mechanical repercussions. The objective of this study was to determine the potential risk of dental fluorosis associated with baby formulas marketed in Spain. We measured 26 baby formulas frequently consumed in Spain; 17 brands for babies aged <6 months, 5 for those aged >6 months, and 4 ready-to-use brands. They were prepared with 4 types of water: distilled water and three brands of bottled water with different levels of fluoride. The fluoride concentration (mg/L or ppm F) was measured with an ion-specific electrode coupled to an ion analyzer. Each sample was prepared according to the manufacturer's instructions and analyzed in triplicate. A descriptive analysis was carried out. The minimum fluoride level found was 0.04 mg/L and the maximum was 1.02 mg/L. Considering the daily intake of these formulas, none exceeded the clinically-acceptable daily dose limit risk for fluorosis (0.07 mg F/day/kg body weight) when mixed with bottled water with a low level of fluoride (0.1 mg/L). However, when the same brands of formula were reconstituted with bottled water with a higher fluoride content (0.99 mg/L), they all exceeded the daily dose limit for the risk of fluorosis. As the potential risk of dental fluorosis associated with the formulas tested depends exclusively on the fluoride concentration of the waters used for reconstitution, formula packaging should contain a warning.

Why orthodontists need to know about molar incisor hypomineralization

Molar incisor hypomineralization (MIH) is a systemic developmental qualitative defect of the enamel that affects 1-4 first permanent molars with or without incisor involvement. Enamel hypomineralization is identified visually as a demarcated opacity with a clear border with varying extensions and can be white, yellow, or brown. This opacity is characterized by a reduced quality of enamel that is of normal thickness but not fully mineralized. It is very common for the affected teeth to present with posteruptive breakdown, making them susceptible to caries, leading to their subsequent loss. Thus, MIH is a significant dental problem with clinical, economic, and psychosocial implications. The planned extraction of compromised teeth is a valid alternative to complex restorative treatment. Orthodontists' involvement is essential in developing effective treatment strategies for children affected by MIH, contributing to their oral health and well-being.

Impact of nutrition on the condition of the oral mucosa and periodontium: A narrative review.

Diet and eating habits significantly affect health and quality of life. Various diets and food eliminations can lead to nutritional deficiencies and malnutrition. This article discusses the relationship between nutrition, nutritional deficiencies, and the condition of the periodontium and oral mucosa. An analysis of PubMed materials was conducted to assess the impact of nutrition on the condition of the oral mucosa and periodontium. We also considered dietary habits such as vegetarianism, the ketogenic diet, the Paleo diet, the Mediterranean diet, the Western diet, and intermittent fasting. Vitamin deficiencies, both watersoluble and fat-soluble, as well as macroand microelements, can manifest in the oral cavity, among others, as gingivitis and bleeding, recurrent aphthous stomatitis, enamel hypomineralization, cheilitis, angular cheilitis, halitosis, glossitis, lingual papillae atrophy, and stomatitis. Malnutrition does not cause periodontal disease, but it increases the risk of its occurrence and accelerates disease progression. Inadequate nutrition, combined with other predisposing factors, may contribute to an increased risk of oral cancer and the development of leukoplakia.

Prevalence and Characteristics of Dental Fluorosis in a Group of Brazilian Children

Background: Dental fluorosis (DF) is characterized by hypomineralization of tooth enamel caused by ingestion of excessive fluoride during enamel formation. DF phenotype presents different severities, ranging from very mild to severe phenotypes according to the enamel alteration. This dental development alteration is a common disorder worldwide. It is important to understand the prevalence in certain populations as a preventive strategy for the child's aesthetic, functional and psychological impairment. Purpose: to evaluate a prevalence and characteristics of DF in a group of children from Brazil. Methods: Three hundred and fifty-three children, aged 8-11 years, were clinically evaluated according to the DF phenotype. Only erupted permanent teeth were assessed. Results: DF prevalence was 7.6 %. Boys showed a higher prevalence of DF than girls. Very mild DF phenotypes were more common than more severe phenotypes of DF. Conclusion: the prevalence of DF in this Brazilian population of children was low.

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

BackgroundChildren’s exposure to secondhand smoke, particularly by their parents, could adversely affect their oral health. Thereby, this study aimed to assess the oral health status of children subjected to household smoking and the impact of smoking patterns on the severity of oral health deterioration.MethodsA total of 210 healthy children were enrolled in this case-control study and allocated into children subjected to household smoking (HS) and control groups. Participants’ guardians were asked to complete a questionnaire regarding sociodemographic characteristics and parental smoking habits. All participants were subjected to clinical dental examination to assess dental caries (ICDAS), hypomineralized primary molars (HSPM), and gingival status (GI). Stimulated saliva samples were collected to assess saliva composition and characteristics. Urine samples were collected and analyzed for cotinine concentration. Data were analyzed using SPSS (v.25) software at a test value of p ≤ 0.05. The t-student test was used to find significant differences between participants’ age, gingival index score, saliva pH, flow rate, sIgA, and cotinine level. The Chi-square test was used to test for the significance of parental employment, number of rooms, gender, sweets consumption, brushing frequency, and HMPM. The correspondence analysis was used to test for significance of parents’ levels of education, type of house ventilation, ICDAS score, smoking form, frequency, and smoking pattern. The correlation between cotinine level and sIgA was tested for association using Bivariate correlation test.ResultsThe HS group showed a significantly increased risk for dental caries (p < 0.000), HSPM lesions (p = 0.007), and GI score (p < 0.000). A significant reduction in salivary flow rate, saliva pH, and sIgA were evident in HS group (p < 0.000). Parental consumption of more than 20 cigarettes/day was accompanied by increased dental caries activity (p < 0.000) and higher risk for increased severity of gingival inflammation (p < 0.000) of children in the HS group. Children of parents who smoke cigarettes and use the hubble/bubble anywhere in the house found to have greater distribution of HSPM (p < 0.000). Reduced sIgA values were found to be significantly associated with increased cotinine concentrations in HS children (p < 0.000).ConclusionsFrequent exposure to household smoking could be associated with an increased risk of dental caries progression, enamel hypomineralization, gingival inflammation, and saliva characteristics changes in children.

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.

Treatment Approaches to Molar Incisor Hypomineralization: A Systematic Review.

This systematic review aimed to comprehensively evaluate the available literature on treating molar incisor hypomineralization (MIH) or enamel hypomineralization published between 2013 and 2023, focusing on identifying relevant studies and their characteristics. The search process encompassed reputable academic databases, including PubMed, Scopus, Cochrane Library, and Web of Science, using a precise keyword strategy ("((molar incisor hypomineralization) OR (enamel hypomineralization)) AND (treatment)"). A total of 637 articles were initially retrieved, followed by a strict selection process adhering to PRISMA guidelines. The inclusion criteria encompassed Randomized Control Trials (RCTs), case series with more than five clinical cases (CSs), studies involving human participants, availability as free full-text or accessible with university credentials, and English-language publications. Exclusion criteria included systematic or literature reviews, editorials, single-case reports, studies conducted in vitro, those involving animals, paid articles, and non-English-language publications. The search yielded 864 articles, of which 23 met the stringent inclusion criteria after a meticulous selection process. These studies will serve as the basis for a comprehensive analysis of MIH treatment approaches. The systematic review ensures the quality and relevance of the chosen studies for a detailed assessment of MIH treatment strategies. This systematic review will provide valuable insights into the characteristics of selected studies, patient profiles, and available treatment options for molar incisor hypomineralization, contributing to a better understanding of this dental condition's management.

Influence of genetics on the occurrence of enamel hypomineralization affecting permanent and primary teeth: A scoping review.

Molar incisor hypomineralization (MIH) is prevalent worldwide and is a challenge for clinicians who provide oral care to children. Molar incisor hypomineralization has been considered a multifactorial disturbance that results from a combination of environmental and genetic factors. This scoping review followed the Joanna Briggs Institute protocol and aimed to identify the available evidence of the genetic influence on the etiology of MIH. The search strategy was conducted in multiple databases, including PubMed, BVS, Embase, Web of Science, and Scopus. Two trained reviewers, requiring a third reviewer in case of disagreements, collected evidence. Of 563 retrieved studies, 17 were included in the review. From 14 studies performed in humans, 10 investigated DNA polymorphisms, one analyzed DNA methylation, one aimed model of inheritance, and two focused on the phenotype in twins or in the family. Three animal studies were based on the null expression of genes. This scoping review, based on the studies that used different methodologies, reinforces the hypothesis of a genetic contribution to the multifactorial etiology of MIH. The available data are limited in terms of size and origin of the samples. Hence, further genetic studies are still required.

A clinical and statistical study on enamel hypomineralization of the first permanent molar in the period of mixed dentition.

The first permanent molar (FPM) is the first tooth in the permanent dentition that emerges in the oral cavity, at around the age of six and behind the deciduous teeth, thus converting the primary dentition into a mixed dentition. Its early formation represents a risk factor for the onset of hard dental tissues disorders, the most common being the molar incisor hypomineralization (MIH). The aim of the study was to assess the hypomineralization type of developmental defects of enamel at FPM level during the mixed dentition stage, in a group of Romanian children. The research was conducted on 87 patients, 44 females and 43 males, divided into the following age groups: 5-6 years, 6-7 years, 7-8 years, 8-9 years, 9-10 years, 10-11 years, 11-12 years and older than 12 years. All children were examined in the dental office by a pediatric dentist. Of the subjects, 40.2% presented hypomineralization lesions on the FPM. Among the affected children, 62.9% were girls and 37.1% were boys. Mild forms were the most prevalent, being found in 71.4% of the affected subjects. Moderate forms were present in 22.9% and severe forms in 5.7% of the affected children. MIH prevalence significantly decreased with increasing age. Only two children belonging to the group 8-9 years and 10-11 years, respectively, showed severe MIH lesions. Statistically significant differences were determined in what regards the distribution of MIH children according to the severity of the lesions in relation to age (p=0.007). Children 6- to 7-year-old have been the most affected by FPM hypomineralization, which indicates the need for early management of the disease, through a thorough diagnosis, and preventive and interceptive therapeutic approaches.

Assessment of Risk Factors for Developmental Defects of the Enamel in Preterm

This study aimed to determine the criteria for quantifying developmental defects of enamel in primary teeth in premature babies and to investigate the severity of developmental defects according to the gestational age, birth weight, systemic complications, and treatments received after preterm birth. Birth information, a history of complications, the duration of parenteral nutrition, and endotracheal intubation were investigated by retrospectively reviewing the admission and discharge records of premature babies in the neonatal intensive care unit. The Preterm Developmental Defects of Enamel (PDDE) index was designed by modifying the existing developmental defects of enamel index. Based on PDDE index, the evaluator scored developmental defects of enamel by classifying them as enamel hypomineralization and hypoplasia. The PDDE scores in the extremely preterm and extremely low birth weight groups were significantly higher than those in other groups. Furthermore, PDDE scores of premature babies with bronchopulmonary dysplasia, rickets, intraventricular hemorrhage, or necrotizing colitis were significantly higher than those in the control group. In addition, more than 50 days of endotracheal intubation and more than 20 days of parenteral nutrition were associated with significantly higher PDDE scores than those in the control group and were risk factors for developmental defects of enamel. This study provides basic information for identifying risk factors for developmental defects of enamel in premature babies.

TGF-β1/Smad3 Signaling Is Required to Alleviate Fluoride-Induced Enamel Hypomineralization.

Excessive fluoride intake during enamel development can affect enamel mineralization, leading to dental fluorosis. However, its potential mechanisms remain largely unexplored. In the present study, we aimed to investigate the impact of fluoride on the expressions of RUNX2 and ALPL during mineralization and the effect of TGF-β1 administration on fluoride treatment. A dental fluorosis model of newborn mice and an ameloblast cell line ALC were both used in the present study. The mice of the NaF group, including the mothers and newborns, were fed with water containing 150ppm NaF after delivery to induce dental fluorosis. The mandibular incisors and molars showed significant abrasion in the NaF group. Immunostaining, qRT-PCR, and Western blotting analysis indicated that exposure to fluoride markedly down-regulated RUNX2 and ALPL in mouse ameloblasts and ALCs. Besides, fluoride treatment significantly decreased the mineralization level detected by ALP staining. Furthermore, exogenous TGF-β1 up-regulated RUNX2 and ALPL and promoted mineralization, while the addition of SIS3 could block such TGF-β1-induced up-regulation. In TGF-β1 conditional knockout mice, the immunostaining of RUNX2 and ALPL was weaker compared with wild-type mice. Exposure to fluoride inhibited the expressions of TGF-β1 and Smad3. Co-treatment of TGF-β1 and fluoride up-regulated RUNX2 and ALPL compared with the fluoride alone treatment, promoting mineralization. Collectively, our data indicated that TGF-β1/Smad3 signaling pathway was necessary for the regulatory effects of fluoride on RUNX2 and ALPL, and the fluoride-induced suppression of ameloblast mineralization was mitigated by activating TGF-β1/Smad3 signaling pathway.

Deficiency of G protein-coupled receptor Gpr111/Adgrf2 causes enamel hypomineralization in mice by alteration of the expression of kallikrein-related peptidase 4 (Klk4) during pH cycling process.

Enamel is formed by the repetitive secretion of a tooth-specific extracellular matrix and its decomposition. Calcification of the enamel matrix via hydroxyapatite (HAP) maturation requires pH cycling to be tightly regulated through the neutralization of protons released during HAP synthesis. We found that Gpr115, which responds to changes in extracellular pH, plays an important role in enamel formation. Gpr115-deficient mice show partial enamel hypomineralization, suggesting that other pH-responsive molecules may be involved. In this study, we focused on the role of Gpr111/Adgrf2, a duplicate gene of Gpr115, in tooth development. Gpr111 was highly expressed in mature ameloblasts. Gpr111-KO mice showed enamel hypomineralization. Dysplasia of enamel rods and high carbon content seen in Gpr111-deficient mice suggested the presence of residual enamel matrices in enamel. Depletion of Gpr111 in dental epithelial cells induced the expression of ameloblast-specific protease, kallikrein-related peptidase 4 (Klk4), suggesting that Gpr111 may act as a suppressor of Klk4 expression. Moreover, reduction of extracellular pH to 6.8 suppressed the expression of Gpr111, while the converse increased Klk4 expression. Such induction of Klk4 was synergistically enhanced by Gpr111 knockdown, suggesting that proper enamel mineralization may be linked to the modulation of Klk4 expression by Gpr111. Furthermore, our in vitro suppression of Gpr111 and Gpr115 expression indicated that their suppressive effect on calcification was additive. These results suggest that both Gpr111 and Gpr115 respond to extracellular pH, contribute to the expression of proteolytic enzymes, and regulate the pH cycle, thereby playing important roles in enamel formation.

Postępowanie kliniczne w amelogenesis imperfecta w wieku rozwojowym – przypadki kliniczne

Amelogenesis imperfecta is a hereditary defect of enamel. It can affect both the primary and permanent dentition. It manifests as: change in enamel structure, shape of teeth, severe malocclusion and can also co-occur with changes in other tissues derived from the ectoderm. In the literature there are several classifications of this disease, the two main ones are the four-stage classification according to Witkop (1988) and the two-stage classification according to Sundell, distinguishing the form associated with enamel hypoplasia and enamel hypomineralization. The aim of this paper is to present the diagnostic and therapeutic management of patients with amelogenesis imperfecta at the developmental age, based on three clinical cases. Three cases were chosen to represent patients with AI: 1) hypoplastic type of AI in 14-year-old girl, 2) hypoplastic type of AI in 12-year-old girl with distoocclusion and retrusion of upper incisors, 3) hypoplastic type of AI in 13-year-old boy with deep overbite and functional retrognathia. Presented methods of treatment were selected depending on the form of lesions, patient’s age and coexisting malocclusion. Direct reconstruction with composite materials was used – free-hand, as well as the technique of indirect reconstruction with steel crowns combined with use of functional orthodontic appliances. Dental treatment in patients with AI should be interdisciplinary. The choice of treatment method depends on the coexisting disorders. It aims to eliminate caries associated with enamel development defects and to correct occlusal conditions, as well as to improve the psychosocial functioning of patients by improving the aesthetics of the teeth.

Treatment of hypomineralized maxillary central and canine teeth with resin infiltration technique: A case report

Aim: The resin infiltration technique is a minimally invasive approach that can be used to treat white spot lesions and arrest the progression of caries lesions. In this case report, it is aimed to eliminate the existing aesthetic problem by treating enamel hypomineralization in the maxillary central and canine teeth with the resin infiltration technique. Methodology: A 17-year-old male patient was referred to our clinic because of an aesthetic problem caused by a white spot lesion in his maxillary central and canine teeth. After clinical and radiological examination, his treatment options were evaluated, and we decided to treat it with the resin infiltration technique. After cleaning the surfaces of the teeth with a prophylaxis pad (Ultrapro Tx, Ultradent, South Jordan, UT, USA), isolation was achieved by applying a gingival barrier (Gingival Barrier, SDI, Bayswater, VIC, Australia). The adjacent teeth were protected using Teflon tape. A 15% hydrochloric acid gel (Icon Etch, DMG, Hamburg, Germany) was applied to the enamel surfaces for two minutes by mixing with a brush. After, the acid was removed using a water spray for 30 seconds. Ethanol (Icon Dry, DMG, Hamburg, Germany) was applied for 30 seconds and air dried. Then, a low-viscosity resin infiltrant (Icon Infiltrant; DMG, Hamburg, Germany) was applied to the tooth surfaces for three minutes by slight massage. After the application, the resin was light polymerized for 40 seconds (D-Light Pro, GC, Tokyo, Japan). The whole procedure was performed in such a way that there were two consecutive cycles. Results: Aesthetics improved after the procedure. The patient was followed up with control sessions. Conclusion: White spot lesions can be treated with a minimally invasive approach using the resin infiltration technique with appropriate indication. How to cite this article: Tüzel S, Çokkeçeci İT, Üçtaşlı MB, Arısu HD. Treatment of hypomineralized maxillary central and canine teeth with resin infiltration technique: A case report. Int Dent Res 2022;12(Suppl.1):124-7. https://doi.org/10.5577/intdentres.452 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Aesthetic Resolution of Enamel Hypomineralization in Single Central Incisor: a Case Report

Abstract Enamel development defects are important complaints of patients, being common in both primary and permanent dentition. This study aims to report a clinical case involving the aesthetic resolution of a permanent maxillary central incisor affected by enamel hypomineralization in a juvenile patient, through the direct restorative technique in a clinical-academic setting. A 16-year-old male patient attended the Clinic School of a college in the north of the state of Minas Gerais complaining of discomfort due to a white spot on the central incisor. In the dental clinical evaluation, a large opaque white spot was observed on tooth 21. The enamel had normal thickness and no surface alteration was observed, consistent with enamel hypomineralization. The decision of the appropriate treatment was taken after the transillumination exam, carried out with the photo-activator device, verifying that the spot was deep. Thus, the treatment option was the restoration with composite resin. The procedure was performed using the stratified technique, using enamel, dentin and effect resins, obtaining an excellent aesthetic result with a wear restricted to the staining area. It may be concluded that a correct diagnostic approach is extremely important for the selection of the appropriate therapy for enamel developmental defects. Composite resin becomes a material of choice when the wear is necessary. Composites have good optical properties and allow less wear compared to dental ceramics. Keywords: Esthetics, Dental. Composite Resins. Tooth Demineralization. ResumoOs defeitos de desenvolvimento de esmalte se apresentam como queixas importantes dos pacientes, sendo comuns tanto na dentição decídua quanto na permanente. O objetivo deste trabalho é relatar um caso clínico que envolve resolução estética de um incisivo central superior permanente afetado por hipomineralização de esmalte em paciente juvenil, através da técnica restauradora direta em ambiente clínico acadêmico. Paciente do sexo masculino, 16 anos de idade, compareceu à Clínica Escola de uma faculdade no norte do estado de Minas Gerais queixando incômodo devido a uma mancha branca em um incisivo central. Na avaliação clínica odontológica observou-se um manchamento branco opaco de grande extensão no dente 21. O esmalte encontrava-se com espessura normal e sem nenhuma alteração superficial, sugerindo ser uma hipomineralização do esmalte. A decisão do tratamento apropriado para o caso então foi tomada mediante um exame de transiluminação, realizado com o próprio aparelho fotoativador, constatando-se que a mancha era profunda, sendo escolhido como terapêutica o desgaste da área de manchamento com posterior restauração em resina composta. O procedimento foi realizado pela técnica estratificada, através de resina de esmalte, dentina e efeito, obtendo-se ao final um resultado estético satisfatório com um desgaste restrito a área de manchamento. Conclui-se que a correta abordagem diagnóstica é de extrema importância para a seleção da terapêutica adequada para os defeitos de desenvolvimento de esmalte. A resina composta torna-se um material de escolha quando há a necessidade de desgaste devido as suas propriedades ópticas interessantes e possibilidade de menor desgaste quando comparado as cerâmicas odontológicas. Palavras-chave: Estética Dentária. Resinas Compostas. Desmineralização do Dente

Energy metabolic shift contributes to the phenotype modulation of maturation stage ameloblasts.

Maturation stage ameloblasts (M-ABs) are responsible for terminal enamel mineralization in teeth and undergo characteristic cyclic changes in both morphology and function between ruffle-ended ameloblasts (RA) and smooth-ended ameloblasts (SA). Energy metabolism has recently emerged as a potential regulator of cell differentiation and fate decisions; however, its implication in M-ABs remains unclear. To elucidate the relationship between M-ABs and energy metabolism, we examined the expression pattern of energy metabolic enzymes in M-ABs of mouse incisors. Further, using the HAT7 cell line with M-AB characteristics, we designed experiments to induce an energy metabolic shift by changes in oxygen concentration. We revealed that RA preferentially utilizes oxidative phosphorylation, whereas SA depends on glycolysis-dominant energy metabolism in mouse incisors. In HAT7 cells, hypoxia induced an energy metabolic shift toward a more glycolytic-dominant state, and the energy metabolic shift reduced alkaline phosphatase (ALP) activity and calcium transport and deposition with a change in calcium-related gene expression, implying a phenotype shift from RA to SA. Taken together, these results indicate that the energy metabolic state is an important determinant of the RA/SA phenotype in M-ABs. This study sheds light on the biological significance of energy metabolism in governing M-ABs, providing a novel molecular basis for understanding enamel mineralization and elucidating the pathogenesis of enamel hypomineralization.

Phenotypic variability in LAMA3-associated amelogenesis imperfecta.

Amelogenesis imperfecta (AI) is defined as inherited enamel malformations. LAMA3 (laminin alpha-3) encodes a critical protein component of the basement membrane (laminin-332). Individuals carrying heterozygous LAMA3 mutations have previously been shown to have localized enamel defects. This study aimed to define clinical phenotypes and to discern the genetic etiology for four AI kindreds. Whole-exome analyses were conducted to search for sequence variants associated with the disorder, and micro-computed tomography (μCT) to characterize the enamel defects. The predominant enamel phenotype was generalized thin enamel with defective pits and grooves. Horizonal bands of hypoplastic enamel with chalky-white discoloration and enamel hypomineralization were also observed and demonstrated by μCT analyses of affected teeth. Four disease-causing LAMA3 mutations (NM_198129.4:c.3712dup; c.5891dup; c.7367del; c.9400G > C) were identified. Compound heterozygous MMP20 mutations (NM_004771.4:c.539A > G; c.692C > T) were also found in one proband with more severe enamel defects, suggesting a mutational synergism on disease phenotypes. Further analyses of the AI-causing mutations suggested that both α3A (short) and α3B (long) isoforms of LAMA3 are essential for enamel formation. Heterozygous LAMA3 mutations can cause generalized enamel defects (AI1A) with variable expressivity. Laminin-332 is critical not only for appositional growth but also enamel maturation.