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Swiss Dental Journal Feb 2024The aim of the treatment of this case was to restore the form, function and aesthetics of all teeth in a patient with amelogenesis imperfecta within the age limit of the...
The aim of the treatment of this case was to restore the form, function and aesthetics of all teeth in a patient with amelogenesis imperfecta within the age limit of the disability insurance (IV). Single-tooth zirconia crowns were selected as the treatment of choice and cemented with a conventional glass ionomer cement. For the maintenance of the oral rehabilitation and the protection of the reconstructions a michigan splint was produced and instructed to be carried over night.
Topics: Humans; Amelogenesis Imperfecta; Crowns; Glass Ionomer Cements; Zirconium; Female; Male; Esthetics, Dental; Dental Prosthesis Design; Occlusal Splints
PubMed: 38739045
DOI: 10.61872/sdj-2024-03-02 -
Journal of Dental Research Jun 2024Amelogenesis imperfecta (AI) is a diverse group of inherited diseases featured by various presentations of enamel malformations that are caused by disturbances at...
Amelogenesis imperfecta (AI) is a diverse group of inherited diseases featured by various presentations of enamel malformations that are caused by disturbances at different stages of enamel formation. While hypoplastic AI suggests a thickness defect of enamel resulting from aberrations during the secretory stage of amelogenesis, hypomaturation AI indicates a deficiency of enamel mineralization and hardness established at the maturation stage. Mutations in , which encodes the largest enamel matrix protein, enamelin, have been demonstrated to cause generalized or local hypoplastic AI. Here, we characterized 2 AI families with disparate hypoplastic and hypomaturation enamel defects and identified 2 distinct indel mutations at the same location of , c588+1del and c.588+1dup. Minigene splicing assays demonstrated that they caused frameshifts and truncation of ENAM proteins, p.Asn197Ilefs*81 and p.Asn197Glufs*25, respectively. In situ hybridization of on mouse mandibular incisors confirmed its restricted expression in secretory stage ameloblasts and suggested an indirect pathogenic mechanism underlying hypomaturation AI. In silico analyses indicated that these 2 truncated ENAMs might form amyloid structures and cause protein aggregation with themselves and with wild-type protein through the added aberrant region at their C-termini. Consistently, protein secretion assays demonstrated that the truncated proteins cannot be properly secreted and impede secretion of wild-type ENAM. Moreover, compared to the wild-type, overexpression of the mutant proteins significantly increased endoplasmic reticulum stress and upregulated the expression of unfolded protein response (UPR)-related genes and , a UPR-controlled proapoptotic gene. Caspase, terminal deoxynucleotidyl transferase UTP nick-end labeling (TUNEL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays further revealed that both truncated proteins, especially p.Asn197Ilefs*81, induced cell apoptosis and decreased cell survival, suggesting that the 2 mutations cause AI through ameloblast cell pathology and death rather than through a simple loss of function. This study demonstrates that an mutation can lead to generalized hypomaturation enamel defects and suggests proteinopathy as a potential pathogenesis for -associated AI.
Topics: Amelogenesis Imperfecta; Animals; Mice; Humans; Ameloblasts; Female; Male; Mutation; Dental Enamel Proteins; Pedigree; Apoptosis; In Situ Hybridization; Extracellular Matrix Proteins
PubMed: 38716742
DOI: 10.1177/00220345241236695 -
International Dental Journal Apr 2024Correct identification and management of Developmental Defects of Enamel (DDEs) are essential to provide the best possible treatment. The present survey aims to...
OBJECTIVES
Correct identification and management of Developmental Defects of Enamel (DDEs) are essential to provide the best possible treatment. The present survey aims to investigate Italian dentists' knowledge of DDEs, their ability to recognise the different clinical pictures, and to choose the most appropriate clinical approach.
METHODS
A cross-sectional survey was planned based on a questionnaire including 27 closed-ended questions, and that proposed 4 clinical pictures, molar incisor hypomineralisation (MIH), amelogenesis imperfecta (AI), dental fluorosis (DF), and an initial caries lesion (ICL). It was distributed by e-mail to all Italian dentists (N = 63,883) through the Italian Federation of Doctors and Dentists. Discrete variables were expressed as absolute and relative frequencies (%). A multivariate analysis assessed whether socio-demographic variables correlated with the answers' truthfulness.
RESULTS
About 5017 questionnaires were included and analysed. Although 90.19% of the sample stated that they had received information on DDEs, a significant percentage did not recognise MIH (36.36%), AI (48.34%), DF (71.50%), and ICL (46.62%). Only 57.07% correctly classified enamel hypomineralisation as a qualitative defect, and even fewer, 54.45%, classified enamel hypoplasia as a quantitative defect. According to the logistic regressions, female dentists, dentists who treat mainly children and received information about DDEs, were more likely to recognise the 4 clinical pictures (P < .01).
CONCLUSIONS
Italian dentists showed many knowledge gaps on DDEs that need to be filled; those who received formal training were more capable of correctly identifying the defects and were more likely to prescribe an appropriate management approach for the defects.
CLINICAL SIGNIFICANCE
Increasing university courses and continuing education on diagnosing and managing DDEs seems reasonable to fill the knowledge gap on DDEs.
PubMed: 38679519
DOI: 10.1016/j.identj.2024.04.013 -
Journal of Dentistry For Children... Jan 2024Enamel renal gingival syndrome is a rare clinical condition characterized by the presence of amelogenesis imperfecta hypoplastic type, gingival fibromatosis and delayed...
Enamel renal gingival syndrome is a rare clinical condition characterized by the presence of amelogenesis imperfecta hypoplastic type, gingival fibromatosis and delayed tooth eruption, in addition to nephrocalcinosis with normal blood calcium levels. It is inherited as an autosomal recessive trait caused by mutations in the FAM20A gene located on chromosome 17q24.2. The purpose of this report is to describe a case of enamel renal gingival syndrome and discuss its distinct features and management.
Topics: Humans; Male; Amelogenesis Imperfecta; Dental Enamel Proteins; Fibromatosis, Gingival; Nephrocalcinosis; Child
PubMed: 38671566
DOI: No ID Found -
Scientific Reports Apr 2024Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes...
Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects. In non-lethal RNS forms, oral traits include a well-studied hypoplastic amelogenesis imperfecta (AI) and a much less characterized gingival phenotype. We used immunomorphological, biochemical, and siRNA approaches to analyze gingival tissues and primary cultures of gingival fibroblasts of two unrelated, previously reported RNS patients. We showed that fibrosis, pathological gingival calcifications and increased expression of various profibrotic and pro-osteogenic proteins such as POSTN, SPARC and VIM were common findings. Proteomic analysis of differentially expressed proteins demonstrated that proteins involved in extracellular matrix (ECM) regulation and related to the TGFβ/SMAD signaling pathway were increased. Functional analyses confirmed the upregulation of TGFβ/SMAD signaling and subsequently uncovered the involvement of two closely related transcription cofactors important in fibrogenesis, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Knocking down of FAM20C confirmed the TGFβ-YAP/TAZ interplay indicating that a profibrotic loop enabled gingival fibrosis in RNS patients. In summary, our in vivo and in vitro data provide a detailed description of the RNS gingival phenotype. They show that gingival fibrosis and calcifications are associated with, and most likely caused by excessed ECM production and disorganization. They furthermore uncover the contribution of increased TGFβ-YAP/TAZ signaling in the pathogenesis of the gingival fibrosis.
Topics: Humans; Transforming Growth Factor beta; Gingiva; Signal Transduction; Proteomics; Fibrosis; YAP-Signaling Proteins; Osteosclerosis; Adaptor Proteins, Signal Transducing; Transcription Factors; Dental Enamel Hypoplasia; Fibroblasts; Microcephaly; Female; Transcriptional Coactivator with PDZ-Binding Motif Proteins; Male; Trans-Activators; Intracellular Signaling Peptides and Proteins; Casein Kinase I; Extracellular Matrix Proteins; Amelogenesis Imperfecta; Cells, Cultured; Abnormalities, Multiple; Cleft Palate; Exophthalmos
PubMed: 38664418
DOI: 10.1038/s41598-024-59713-0 -
BMJ Case Reports Apr 2024Heimler Syndrome 2 (HS-2) is a rare, autosomal recessive mild form of a peroxisomal biogenesis disorder. Though knowledge regarding the disorder is limited, emerging...
Heimler Syndrome 2 (HS-2) is a rare, autosomal recessive mild form of a peroxisomal biogenesis disorder. Though knowledge regarding the disorder is limited, emerging research has found that sensorineural hearing loss, occasional or late onset pigmentation, amelogenesis imperfecta and nail abnormalities are clinical characteristics representative of HS-2.A school-aged male presented to the dental department with a chief complaint of a lack of enamel on multiple teeth. The patient's medical history was significant for patent ductus arteriosus, bilateral sensorineural hearing loss and biallelic mutation of the PEX6 gene. The clinical exam revealed dental crowding, hypoplasia, hypo-calcification of multiple teeth and enlarged pulp chambers of maxillary molars. This case report details the clinical findings associated with HS-2, the comprehensive dental treatment to be rendered to the patient, and critical information to paediatric dentists and general dentists so that they can make proper referrals to medical specialties.
Topics: Humans; Male; Child; Hearing Loss, Sensorineural
PubMed: 38663901
DOI: 10.1136/bcr-2023-257354 -
Journal of Endodontics Jul 2024Regional odontodysplasia (ROD) is a rare developmental disorder characterized by hypo-mineralization and hypoplasia of enamel and dentin. Symptoms include poorly...
INTRODUCTION
Regional 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 REPORT
A 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.
CONCLUSION
The 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.
Topics: Humans; Adolescent; Female; Regenerative Endodontics; Odontodysplasia; Incisor; Bicuspid; Root Canal Therapy; Dental Pulp Necrosis
PubMed: 38626857
DOI: 10.1016/j.joen.2024.04.006 -
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke... Mar 2024
Topics: Humans; Phenotype; Mutation; Amelogenesis Imperfecta; Hearing Loss, Sensorineural; Nails, Malformed
PubMed: 38561264
DOI: 10.3760/cma.j.cn115330-20240117-00033 -
The Chinese Journal of Dental Research Mar 2024To investigate FAM20A gene variants and histological features of amelogenesis imperfecta and to further explore the functional impact of these variants.
OBJECTIVE
To investigate FAM20A gene variants and histological features of amelogenesis imperfecta and to further explore the functional impact of these variants.
METHODS
Whole-exome sequencing (WES) and Sanger sequencing were used to identify pathogenic gene variants in three Chinese families with amelogenesis imperfecta. Bioinformatics analysis, in vitro histological examinations and experiments were conducted to study the functional impact of gene variants, and the histological features of enamel, keratinised oral mucosa and dental follicle.
RESULTS
The authors identified two nonsense variants c. 406C > T (p.Arg136*) and c.826C > T (p.Arg176*) in a compound heterozygous state in family 1, two novel frameshift variants c.936dupC (p.Val313Argfs*67) and c.1483dupC (p.Leu495Profs*44) in a compound heterozygous state in family 2, and a novel homozygous frameshift variant c.530_531insGGTC (p.Ser178Valfs*21) in family 3. The enamel structure was abnormal, and psammomatoid calcifications were identified in both the gingival mucosa and dental follicle. The bioinformatics and subcellular localisation analyses indicated these variants to be pathogenic. The secondary and tertiary structure analysis speculated that these five variants would cause structural damage to FAM20A protein.
CONCLUSION
The present results broaden the variant spectrum and clinical and histological findings of diseases associated with FAM20A, and provide useful information for future genetic counselling and functional investigation.
Topics: Humans; Amelogenesis Imperfecta; Calcification, Physiologic; Computational Biology; Dental Enamel; Dental Enamel Proteins; East Asian People
PubMed: 38546520
DOI: 10.3290/j.cjdr.b5136761