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Physiological Reviews Jul 2017Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as... (Review)
Review
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
Topics: Ameloblasts; Amelogenesis; Animals; Dental Enamel; Dental Enamel Proteins; Evolution, Molecular; Genetic Predisposition to Disease; Humans; Oral Health; Phenotype; Species Specificity; Tooth Abnormalities; Tooth Diseases
PubMed: 28468833
DOI: 10.1152/physrev.00030.2016 -
Journal of Medical Case Reports Feb 2021Rehabilitation of the entire dentition with amelogenesis imperfecta (AI) tends to pose a great challenge to the clinician. Most of the cases of amelogenesis imperfecta... (Review)
Review
BACKGROUND
Rehabilitation of the entire dentition with amelogenesis imperfecta (AI) tends to pose a great challenge to the clinician. Most of the cases of amelogenesis imperfecta are reported to be associated with skeletal and dental deformities which results in severe sensitivity of the dental tissues.
CASE PRESENTATION
This clinical case report marks out the total restoration of the oral condition of a young Indian patient diagnosed with the hypoplastic type of amelogenesis imperfecta. Fixed metal ceramic prosthesis were planned to strengthen the masticatory activity, aesthetics, to banish the dental sensitivity and to build up the general persona of the patient. The patient was followed-up at 6 months, 1 year and 2 years intervals. Functional and esthetic impairment was not visible after the follow up period and the treatment outcome was successful. The entire treatment plan was intended to enhance the functional, esthetic and the masticatory component of the occlusal architecture.
CONCLUSION
This case report details the presentation, characteristic radiographic findings, and management of a patient with an extremely rare condition of amelogenesis imperfecta.
Topics: Amelogenesis Imperfecta; Esthetics, Dental; Humans; Patient Care Planning; Treatment Outcome
PubMed: 33557885
DOI: 10.1186/s13256-020-02586-4 -
PloS One 2021Molar incisor hypomineralization (MIH) is an enamel condition characterized by lesions ranging in color from white to brown which present rapid caries progression, and... (Clinical Trial)
Clinical Trial
Molar incisor hypomineralization (MIH) is an enamel condition characterized by lesions ranging in color from white to brown which present rapid caries progression, and mainly affects permanent first molars and incisors. These enamel defects usually occur when there are disturbances during the mineralization or maturation stage of amelogenesis. Both genetic and environmental factors have been suggested to play roles in MIH's development, but no conclusive risk factors have shown the source of the disease. During head and neck development, the interferon regulatory factor 6 (IRF6) gene is involved in the structure formation of the oral and maxillofacial regions, and the transforming growth factor alpha (TGFA) is an essential cell regulator, acting during proliferation, differentiation, migration and apoptosis. In this present study, it was hypothesized that these genes interact and contribute to predisposition of MIH. Environmental factors affecting children that were 3 years of age or older were also hypothesized to play a role in the disease etiology. Those factors included respiratory issues, malnutrition, food intolerance, infection of any sort and medication intake. A total of 1,065 salivary samples from four different cohorts were obtained, and DNA was extracted from each sample and genotyped for nine different single nucleotide polymorphisms. Association tests and logistic regression implemented in PLINK were used for analyses. A potential interaction between TGFA rs930655 with all markers tested in the cohort from Turkey was identified. These interactions were not identified in the remaining cohorts. Associations (p<0.05) between the use of medication after three years of age and MIH were also found, suggesting that conditions acquired at the age children start to socialize might contribute to the development of MIH.
Topics: Adolescent; Amelogenesis; Child; Dental Enamel Hypoplasia; Female; Gene-Environment Interaction; Genotype; Humans; Incisor; Male; Molar; Polymorphism, Single Nucleotide; Transforming Growth Factor alpha
PubMed: 33406080
DOI: 10.1371/journal.pone.0241898 -
Odontology Sep 2016Mineralization defects like amelogenesis imperfecta are often of hereditary origin. This article reviews the diagnostic findings and summarizes the suggested treatment... (Review)
Review
Mineralization defects like amelogenesis imperfecta are often of hereditary origin. This article reviews the diagnostic findings and summarizes the suggested treatment approaches. Currently, there are no defined therapy recommendations available for patients suffering from amelogenesis imperfecta. The mentioned therapies are more or less equal but no comprehensive therapy recommendation is evident. When treating patients suffering from amelogenesis imperfecta, a comprehensive therapy of almost every dental discipline has to be considered. The earlier the diagnosis of amelogenesis imperfecta is confirmed, the better the outcome is. Optimal treatment approaches consist of early diagnosis and treatment approach and frequent dental recall appointments to prevent progressive occlusal wear or early destruction by caries. Full-mouth prosthetic treatment seems to be the best treatment option.
Topics: Amelogenesis Imperfecta; Diagnosis, Differential; Disease Progression; Early Diagnosis; Esthetics, Dental; Humans
PubMed: 27550338
DOI: 10.1007/s10266-016-0266-1 -
Developmental Cell Oct 2023Tooth enamel secreted by ameloblasts (AMs) is the hardest material in the human body, acting as a shield to protect the teeth. However, the enamel is gradually damaged...
Tooth enamel secreted by ameloblasts (AMs) is the hardest material in the human body, acting as a shield to protect the teeth. However, the enamel is gradually damaged or partially lost in over 90% of adults and cannot be regenerated due to a lack of ameloblasts in erupted teeth. Here, we use single-cell combinatorial indexing RNA sequencing (sci-RNA-seq) to establish a spatiotemporal single-cell census for the developing human tooth and identify regulatory mechanisms controlling the differentiation process of human ameloblasts. We identify key signaling pathways involved between the support cells and ameloblasts during fetal development and recapitulate those findings in human ameloblast in vitro differentiation from induced pluripotent stem cells (iPSCs). We furthermore develop a disease model of amelogenesis imperfecta in a three-dimensional (3D) organoid system and show AM maturation to mineralized structure in vivo. These studies pave the way for future regenerative dentistry.
Topics: Humans; Ameloblasts; Amelogenesis; Dental Enamel; Odontogenesis; Tooth
PubMed: 37582367
DOI: 10.1016/j.devcel.2023.07.013 -
Journal of Esthetic and Restorative... Jan 2019Defects in the maturation stage of amelogenesis result in a normal volume of enamel but insufficient mineralization, called hypomineralization. Molar-incisor...
INTRODUCTION
Defects in the maturation stage of amelogenesis result in a normal volume of enamel but insufficient mineralization, called hypomineralization. Molar-incisor hypomineralization (MIH), amelogenesis imperfecta and dental fluorosis (DF) are examples of such defects.
OBJECTIVE
To evaluate the effectiveness of the treatments applied to the different forms of dental hypomineralization.
MATERIALS AND METHODS
PubMed, Scopus, Cochrane Library, Web of Science, and Embase were screened. The research was limited to studies published in English, Spanish, and Portuguese, until May 30, 2018. The research question was formulated following the Population, Intervention, Comparison, Outcome strategy. The quality of the methodology of each article was evaluated employing the Cochrane Handbook for Systematic Reviews.
RESULTS
From the initial research, 7895 references were obtained, of which 33 were included in the systematic review. The following treatments were reported: desensitizing and remineralizing products, resin infiltration, restorations, fissure sealants, tooth bleaching, enamel microabrasion and calcium, and vitamins supplements.
CONCLUSIONS
Although the results are suggestive, there is a clear need for a greater uniformity of the methodologies, thus allowing for the development of clinical guidelines. Nevertheless, it was possible to identify several effective treatments for teeth with MIH (arginine pastes or fluoride varnishes) and DF (tooth bleaching and/or enamel microabrasion).
CLINICAL SIGNIFICANCE
Because MIH, amelogenesis imperfecta, and DF are commonly seen in dental daily practice, it is extremely important to analyze the literature regarding its treatment.
Topics: Dental Enamel; Dental Enamel Hypoplasia; Humans; Incisor; Molar; Pit and Fissure Sealants
PubMed: 30284749
DOI: 10.1111/jerd.12420 -
Advances in Experimental Medicine and... 2020Heimler syndrome is a rare syndrome associating sensorineural hearing loss with retinal dystrophy and amelogenesis imperfecta due to PEX1 or PEX6 biallelic pathogenic... (Review)
Review
Heimler syndrome is a rare syndrome associating sensorineural hearing loss with retinal dystrophy and amelogenesis imperfecta due to PEX1 or PEX6 biallelic pathogenic variations. This syndrome is one of the less severe forms of peroxisome biogenesis disorders. In this chapter, we will review clinical, biological, and genetic knowledges about the Heimler syndrome.
Topics: ATPases Associated with Diverse Cellular Activities; Amelogenesis Imperfecta; Hearing Loss, Sensorineural; Humans; Membrane Proteins; Nails, Malformed; Peroxisomal Disorders
PubMed: 33417209
DOI: 10.1007/978-3-030-60204-8_7 -
International Journal of Environmental... Jul 2021Amelogenesis imperfecta (AI) is defined as an interruption of enamel formation due to genetic inheritance. To prevent malfunction of the masticatory system and an...
Amelogenesis imperfecta (AI) is defined as an interruption of enamel formation due to genetic inheritance. To prevent malfunction of the masticatory system and an unaesthetic appearance, various treatment options are described. While restoration with a compomer in the anterior region and stainless steel crowns in the posterior region is recommended for deciduous dentition, the challenges when treating such structural defects in mixed or permanent dentition are changing teeth and growing jaw, allowing only temporary restoration. The purpose of this case report is to demonstrate oral rehabilitation from mixed to permanent dentition. The dentition of a 7-year-old patient with AI type I and a 12-year-old patient with AI type II was restored under general anesthesia to improve their poor aesthetics and increase vertical dimension, which are related to problems with self-confidence and reduced oral health quality of life. These two cases show the complexity of dental care for structural anomalies of genetic origin and the challenges in rehabilitating the different phases of dentition.
Topics: Amelogenesis Imperfecta; Child; Crowns; Dentition, Permanent; Humans; Quality of Life; Self Concept
PubMed: 34281141
DOI: 10.3390/ijerph18137204 -
L' Orthodontie Francaise Nov 2023The precise diagnosis of dental structural anomalies is an essential step preceding our restorative and orthodontic therapies. Indeed, first of all, it is necessary to...
INTRODUCTION
The precise diagnosis of dental structural anomalies is an essential step preceding our restorative and orthodontic therapies. Indeed, first of all, it is necessary to identify the type of structural anomaly and to determine if it is an isolated or a syndromic form: the dental anomaly could be included in a more complex clinical picture combining other clinical signs. Moreover, the establishment of the diagnosis will allow the practitioner to adapt his clinical protocol according to the observed dental structure anomaly. The choice of the bonding material, the type of preparation (no prep, prep less, complete eviction), and the application of a deproteinization protocol with sodium hypochlorite depend to the structural defect.
MATERIAL AND METHOD
The diagnosis of dental structural anomalies is based on several key points described in this article in order to facilitate the practitioner's diagnostic approach.
CONCLUSION
The diagnosis of amelogenesis or dentinogenesis imperfecta should justify the search for other signs to determine whether the anomaly of tooth structure is isolated or syndromic.
Topics: Humans; Amelogenesis; Dental Materials; Sodium Hypochlorite
PubMed: 37930342
DOI: 10.1684/orthodfr.2023.134 -
Monographs in Oral Science 2021Mutations in several genes can lead to amelogenesis imperfecta. These same genes and other members of their pathways quite possibly may also contribute to individual... (Review)
Review
Mutations in several genes can lead to amelogenesis imperfecta. These same genes and other members of their pathways quite possibly may also contribute to individual susceptibility to dental caries and/or erosive tooth wear. This chapter provides an analysis of the function of the genes which, when mutated, cause amelogenesis imperfecta and discusses how mechanisms involving hypomorphic alleles in one or more genes, methylation changes, and imprinting disorders could be underlying individual susceptibility to dental caries and/or erosive tooth wear.
Topics: Amelogenesis Imperfecta; Dental Caries; Humans; Mutation; Tooth Wear
PubMed: 35078171
DOI: 10.1159/000520764