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The Saudi Dental Journal Jul 2022This work aimed to study the rate and quality of maturation of the mineral component of retained teeth 3.8, 4.8 and lower jaw fragment of a human in connective tissue...
PURPOSE
This work aimed to study the rate and quality of maturation of the mineral component of retained teeth 3.8, 4.8 and lower jaw fragment of a human in connective tissue dysplasia in different periods of postpartum ontogenesis.
METHODS
The study involved 102 men (76 with connective tissue dysplasia and 26 without connective tissue dysplasia) divided into groups by age: 31-40, 41-50, 51-60 years. One tooth 3.8, 4.8 and a fragment of the alveolar part of the lower jaw in the projection of teeth 3.8, 4.8 0.5*0.5 cm in size were extracted from each examinee for medical indications.
RESULTS
Low optical density values are observed at the age of 41-50 years, at the age of 51-60 years, indicating decreased mineral density and the presence of total areas of hypomineralization from the age 31-40 years in connective tissue dysplasia. At the age of 41-50, 51-60 years, at the boundary of connective tissue structures and periosteum, a pronounced sclerosis and deformation of delineation elements were observed; at the age of 31-40 years, the indicated changes were less pronounced. At the age of 31-40 years, the level of bone plate dissection has a local character, after 40 years, it has a generalized character.
CONCLUSION
Progressive osteoporosis of the mandible and incomplete amelogenesis are an obstacle to the correct and harmonious teething of the lower wisdom teeth after the age of 30.
PubMed: 35814839
DOI: 10.1016/j.sdentj.2022.05.002 -
Ecotoxicology and Environmental Safety Jul 2023Perfluorooctanoic acid (PFOA) is an artificial fluorinated organic compound that has generated increased public attention due to its potential health hazards. Unsafe...
Perfluorooctanoic acid (PFOA) is an artificial fluorinated organic compound that has generated increased public attention due to its potential health hazards. Unsafe levels of PFOA exposure can affect reproduction, growth and development. During tooth enamel development (amelogenesis), environmental factors including fluoride can cause enamel hypoplasia. However, the effects of PFOA on ameloblasts and tooth enamel formation remain largely unknown. In the present study we demonstrate several PFOA-mediated cell death pathways (necrosis/necroptosis, and apoptosis) and assess the roles of ROS-MAPK/ERK signaling in PFOA-mediated cell death in mouse ameloblast-lineage cells (ALC). ALC cells were treated with PFOA. Cell proliferation and viability were analyzed by MTT assays and colony formation assays, respectively. PFOA suppressed cell proliferation and viability in a dose dependent manner. PFOA induced both necrosis (PI-positive cells) and apoptosis (cleaved-caspase-3, γH2AX and TUNEL-positive cells). PFOA significantly increased ROS production and up-regulated phosphor-(p)-ERK. Addition of ROS inhibitor N-acetyl cysteine (NAC) suppressed p-ERK and decreased necrosis, and increased cell viability compared to PFOA alone, whereas NAC did not change apoptosis. This suggests that PFOA-mediated necrosis was induced by ROS-MAPK/ERK signaling, but apoptosis was not associated with ROS. Addition of MAPK/ERK inhibitor PD98059 suppressed necrosis and increased cell viability compared to PFOA alone. Intriguingly, PD98059 augmented PFOA-mediated apoptosis. This suggests that p-ERK promoted necrosis but suppressed apoptosis. Addition of the necroptosis inhibitor Necrostatin-1 restored cell viability compared to PFOA alone, while pan-caspase inhibitor Z-VAD did not mitigate PFOA-mediated cell death. These results suggest that 1) PFOA-mediated cell death was mainly caused by necrosis/necroptosis by ROS-MAPK/ERK signaling rather than apoptosis, 2) MAPK/ERK signaling plays the dual roles (promoting necrosis and suppressing apoptosis) under PFOA treatment. This is the initial report to indicate that PFOA could be considered as a possible causative factor for cryptogenic enamel malformation. Further studies are required to elucidate the mechanisms of PFOA-mediated adverse effects on amelogenesis.
Topics: Mice; Animals; Reactive Oxygen Species; Ameloblasts; Cell Death; Necrosis
PubMed: 37271104
DOI: 10.1016/j.ecoenv.2023.115089 -
Journal of Postgraduate Medicine 2024We report a 2.2 year-old-boy, born of consanguineous marriage, referred for short stature, with history of neonatal death and skeletal deformities in his older sibling....
We report a 2.2 year-old-boy, born of consanguineous marriage, referred for short stature, with history of neonatal death and skeletal deformities in his older sibling. Rhizo-mesomelic dwarfism was detected antenatally. Within 24 hours of birth, he developed multiple seizures. Examination revealed severe short stature, dolichocephaly, broad forehead, deep set eyes, low set ears, bulbous nose, small, irregular teeth, pointed chin, and triangular facies. He had rhizomelic shortening, stubby fingers, pes planus, and scanty hair. Neurological evaluation revealed ataxia, hypotonia, and global developmental delay. Skeletal survey radiograph revealed shallow acetabuli, short femurs and humerus, short, broad metacarpals and short cone-shaped phalanges with cupping of phalangeal bases. Clinical exome analysis revealed homozygous mutations involving the POC1A gene and the SLC13A5 gene responsible for SOFT syndrome and Kohlschutter-Tonz syndrome respectively, which were inherited from the parents. Both these syndromes are extremely rare, and their co-occurrence is being reported for the first time.
Topics: Male; Infant, Newborn; Humans; Child, Preschool; Epilepsy; Dementia; Amelogenesis Imperfecta; Abnormalities, Multiple; Osteochondrodysplasias; Dwarfism; Symporters; Cytoskeletal Proteins; Cell Cycle Proteins
PubMed: 37706418
DOI: 10.4103/jpgm.jpgm_1001_22 -
Frontiers in Physiology 2022The distinct morphology adopted by ameloblasts during amelogenesis is highly stage specific and involved intimately with the development of a hierarchical enamel...
The distinct morphology adopted by ameloblasts during amelogenesis is highly stage specific and involved intimately with the development of a hierarchical enamel microstructure. The molecular mechanisms that govern the development of an elongated and polarized secretory ameloblast morphology and the potential roles played by the enamel matrix proteins in this process are not fully understood. Thus far, the models that have been developed to mimic these early cell-matrix interactions have either been unable to demonstrate direct morphological change or have failed to adapt across ameloblast cell lines. Here, we use a recently established 3D cell culture model to examine the interactions between HAT-7 cells and the major enamel matrix proteins, amelogenin and ameloblastin. We demonstrate that HAT-7 cells selectively respond to functional EMPs in culture by forming clusters of tall cells. Aspect ratio measurements from three-dimensional reconstructions reveal that cell elongation is 5-times greater in the presence of EMPs when compared with controls. Using confocal laser scanning microscopy, we observe that these clusters are polarized with asymmetrical distributions of Par-3 and claudin-1 proteins. The behavior of HAT-7 cells in 3D culture with EMPs is comparable with that of ALC and LS-8 cells. The fact that the 3D model presented here is tunable with respect to gel substrate composition and ameloblast cell type highlights the overall usefulness of this model in studying ameloblast cell morphology .
PubMed: 36531170
DOI: 10.3389/fphys.2022.1069519 -
Journal of Molecular Histology Dec 2019Mutations in the gene encoding family with sequence similarity 20, member A (FAM20A) caused amelogenesis imperfecta (AI), in humans. However, the roles of FAM20A in...
Mutations in the gene encoding family with sequence similarity 20, member A (FAM20A) caused amelogenesis imperfecta (AI), in humans. However, the roles of FAM20A in amelogenesis and dentinogenesis are poorly understood. In this study, we generated a Fam20a knockout (Sox2-Cre;Fam20a) mouse model by crossing Fam20a mice with Sox2-Cre transgenic mice, in which Fam20a was ablated in both dental epithelium and dental mesenchyme. We found that these mice developed an enamel phenotype that resembles human AI associated with FAM20A mutations, but did not have apparent dentin defects. The secretory stage ameloblasts in the mandibular incisors from the Sox2-Cre;Fam20a mice were shorter and detached from the enamel matrix, and subsequently lost their polarity, became disorganized and formed numerous spherical extracellular matrices in place of normal enamel. At the molecular level, the Sox2-Cre;Fam20a mice displayed dramatically reduced expression levels of the genes encoding the enamel matrix proteins, but unaltered levels of the genes encoding the dentin matrix proteins. Moreover, Fam20a ablation resulted in a great decrease in FAM20C protein level, but it did not alter the intracellular localization of FAM20C protein in ameloblasts and odontoblasts. These results indicate that FAM20A is essential for amelogenesis, but is dispensable for dentinogenesis.
Topics: Ameloblasts; Amelogenesis; Amelogenesis Imperfecta; Animals; Calcium-Binding Proteins; Dental Enamel; Dental Enamel Proteins; Dentin; Dentinogenesis; Extracellular Matrix Proteins; Humans; Mice, Knockout; Mice, Transgenic; Mutation; Odontoblasts; SOXB1 Transcription Factors
PubMed: 31667691
DOI: 10.1007/s10735-019-09851-x -
JMIR Research Protocols Nov 2021Enamel renal syndrome (ERS) (OMIM 204690) is a rare autosomal recessive disorder characterized by hypoplastic amelogenesis imperfecta, failed tooth eruption, intrapulpal...
BACKGROUND
Enamel renal syndrome (ERS) (OMIM 204690) is a rare autosomal recessive disorder characterized by hypoplastic amelogenesis imperfecta, failed tooth eruption, intrapulpal calcifications, gingival enlargement, and nephrocalcinosis. The rarity of the condition and the variability of the phenotype has led to ERS not being fully characterized.
OBJECTIVE
This scoping review aims to account for the range and current state of knowledge on ERS and synthesize these findings into a comprehensive summary, focusing on the pathophysiology, genotype-phenotype correlations, and patient management from a dental perspective.
METHODS
The authors will conduct a systematic search of PubMed (MEDLINE), BioMed Central, EbscoHost Web, Web of Science, and WorldCat. We will include all studies with human participants with a confirmed diagnosis of ERS. Articles will be screened in two stages (ie, initially by title and abstract screening and then full-text screening by two independent reviewers). Data extraction will be conducted using a customized electronic data extraction form. We will provide a narrative synthesis of the findings from the included studies. We will structure the results according to themes.
RESULTS
This protocol is registered with the Open Science Framework. The electronic search was conducted in July 2020 and updated in April 2021. The research findings will be published in an open access journal.
CONCLUSIONS
Dentists should be able to identify patients with clinical features of ERS so that they receive appropriate referrals for renal evaluation, genetic counseling, and oral rehabilitation to increase the patient's quality of life. A scoping review is the most appropriate method to conduct this comprehensive exploration of the current evidence, which may be sparse due to the rarity of the condition. It will also enable us to identify gaps in the research.
TRIAL REGISTRATION
Open Science Framework; https://osf.io/cghsa.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)
DERR1-10.2196/29702.
PubMed: 34851300
DOI: 10.2196/29702 -
Frontiers in Cell and Developmental... 2021Melatonin, an endogenous neurohormone, modulates the biological circadian rhythms of vertebrates. It functions have been reported in previous stomatological studies as...
Melatonin, an endogenous neurohormone, modulates the biological circadian rhythms of vertebrates. It functions have been reported in previous stomatological studies as anti-inflammation, antioxidant, osseointegration of dental implants and stimulation to dental pulp stem cells differentiation, but its role in ameloblastic differentiation and mineralization has been rarely studied. To reveal the effects of melatonin on the mineralization of ameloblast lineage cells (ALCs), and to identify the change in gene expression and the potential mechanism based on ribonucleic acid sequencing (RNA-seq) analysis. ALCs were induced in melatonin-conditioned medium. After 7-days culture, Western blot, real-time PCR, alkaline phosphatase (ALP) activity test, RNA-seq were accordingly used to detect the change in molecular level. After 1-month odontogenic induction in melatonin medium, Alizarin Red-S (ARS) staining showed the changes of mineral nodules. Differentially expressed genes (DEGs), enrichment of functions and signaling pathways analysis based on Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) database were performed. The JNK3 antagonist (JNK3 inhibitor IX, SR3576) and β-arrestin1 (Arrb1) overexpression were applied to confirm the fluctuation of melatonin-medicated JNK3 and Arrb1 expression. In this study, we found out melatonin contributed to the ameloblastic mineralization, from which we can observed the elevated expression of enamel matrix protein, and increased ALP activity and mineralized nodules formation. RNA-seq analysis showed the up-regulation of neural JNK3 and down-regulation of Arrb1 in ALCs. Meanwhile, phosphorylated JNK3 deficiency (phosphorylated JNK3 inhibitor---SR3576 added to culture medium) led to mineralization delay, and Arrb1 overexpression proved Arrb1 takes bridge between melatonin receptors (MTNR) and JNK3 in MAPK signaling pathway.
PubMed: 35004671
DOI: 10.3389/fcell.2021.749642 -
Journal of Personalized Medicine Dec 2021Amelogenesis imperfecta (AI) is a rare genetic condition affecting the quantity and/or quality of tooth enamel. Hypomaturation AI is characterized by brownish-yellow...
Amelogenesis imperfecta (AI) is a rare genetic condition affecting the quantity and/or quality of tooth enamel. Hypomaturation AI is characterized by brownish-yellow discoloration with increased opacity and poorly mineralized enamel prone to fracture and attrition. We recruited three families affected by hypomaturation AI and performed whole exome sequencing with selected individuals in each family. Bioinformatic analysis and Sanger sequencing identified and confirmed mutations and segregation in the families. Family 1 had a novel homozygous frameshift mutation in gene (NM_003485.3:c.78_83delinsC, p.(Val27Cysfs*146)). Family 2 had a novel homozygous nonsense mutation in gene (NM_153646.4:c.613C>T, NP_705932.2:p.(Arg205*)). Family 3 also had a homozygous missense mutation in gene which was reported previously (c.437C>T, p.(Ala146Val)). This report not only expands the mutational spectrum of the AI-causing genes but also improves our understanding of normal and pathologic amelogenesis.
PubMed: 35055328
DOI: 10.3390/jpm12010013 -
International Journal of Paediatric... Nov 2022Amelogenesis imperfecta (AI) is an inherited disorder of enamel development that is challenging to treat and often associated with negative patient and parental...
BACKGROUND
Amelogenesis imperfecta (AI) is an inherited disorder of enamel development that is challenging to treat and often associated with negative patient and parental outcomes. Social media provides a valuable perspective on patients' and dental professionals' experience of AI and dental care.
AIM
To explore how the public and dental professionals use social media to discuss AI.
DESIGN
A cross-sectional study involving a systemic search of eight social media platforms using the search term 'amelogenesis imperfecta'. Relevant posts were selected using predefined eligibility criteria. Word content of eligible posts was qualitatively analysed using a thematic framework approach.
RESULTS
A total of 555 posts were identified, of which 144 were eligible for analysis. For dental professionals, the posts included case reports and seeking and sharing of information. For the public, the posts were related to individuals' experience of AI, dental treatment and outcome of treatment.
CONCLUSIONS
Posts from individuals affected by AI suggest a need for better distribution of reliable information and greater support. Case reports indicate that dental professionals find it challenging to recognise AI and determine appropriate treatment options. Social media could potentially be used to inform and support people with AI and allow dental professionals to share information and learning with peers.
Topics: Amelogenesis; Amelogenesis Imperfecta; Cross-Sectional Studies; Dentists; Humans; Social Media
PubMed: 35771161
DOI: 10.1111/ipd.13015 -
Journal of Pediatric Ophthalmology and... 2024To report two new cases with confirmed diagnosis of Heimler syndrome and describe their systemic and ophthalmic phenotype and visual rehabilitation. (Review)
Review
PURPOSE
To report two new cases with confirmed diagnosis of Heimler syndrome and describe their systemic and ophthalmic phenotype and visual rehabilitation.
METHODS
Retrospective review of medical records.
RESULTS
Both siblings were diagnosed as having sensori-neural hearing loss and retinal dystrophy with exuberant intraretinal cystoid spaces and cone-rod dysfunction. The older sibling also had amelogenesis imperfecta and neither had nail abnormalities. Genetic analysis identified homozygosity for the pathogenic variant c.2528G>A p.(Gly843Asp) in the gene in both siblings. The parents were heterozygous carriers of the variant.
CONCLUSIONS
The authors report a familial case of Heimler syndrome due to biallelic pathogenic variants that manifested as macular dystrophy characterized by cone-rod dysfunction and complicated by intraretinal cystoid spaces. Review of the literature shows that ocular phenotype is variable in patients with Heimler syndrome. .
Topics: Humans; Amelogenesis Imperfecta; Mutation; Siblings; Nails, Malformed; Phenotype; Eye Abnormalities; Pedigree; ATPases Associated with Diverse Cellular Activities; Membrane Proteins; Hearing Loss, Sensorineural
PubMed: 37092661
DOI: 10.3928/01913913-20230220-01