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Journal of the Mechanical Behavior of... Aug 2021The aim of this study was to investigate the wear behavior of Dentinogenesis imperfecta type II (DGI-II) dentin and elucidate the correlation between its tribological...
OBJECTIVES
The aim of this study was to investigate the wear behavior of Dentinogenesis imperfecta type II (DGI-II) dentin and elucidate the correlation between its tribological properties and components.
METHODS
The mid-coronal dentin of normal and DGI-II teeth were divided into two groups: perpendicular and parallel to the dentin tubules. The microstructure of dentin was detected using atomic force microscopy (AFM). The wear behavior of dentin was evaluated by nanoscratch tests and scanning electron microscopy (SEM). Meanwhile, changes in molecular groups and chemical composition were analyzed by Raman and Energy-Dispersive X-ray (EDX) tests, respectively. Nanohardness was also evaluated.
RESULTS
AFM images of DGI-II dentin illustrated a decrease in the number of tubules and the tubule diameter. Nanoscratch test showed a higher friction coefficient and a greater depth-of-scratch in DGI-II dentin. The wear resistance of DGI-II dentin was reduced independent of tubule orientation. EDX results indicated that DGI-II dentin mineral content decreased and Raman spectra results showed DGI-II dentin had a decreased collagen matrix structure stability coupled with hypomineralization. Furthermore, a significant reduction in nanohardness and elastic modulus of DGI-II dentin was observed. Regression analysis revealed a close correlation between dentin components and inferior wear resistance.
CONCLUSIONS
All results indicated the wear behavior of DGI-II dentin was significantly deteriorated, presumably caused by the disorder in microstructures and the reduction of chemical composition.
Topics: Collagen; Dentin; Dentinogenesis Imperfecta; Humans; Microscopy, Electron, Scanning
PubMed: 34010797
DOI: 10.1016/j.jmbbm.2021.104585 -
Dentistry Journal Apr 2021Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding...
Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding genes. The current study aimed to evaluate dentinogenesis imperfecta (DI), oral manifestations and caries status of OI children. Sixty-eight children (41 males, 27 females) aged from 3 to 17 years old (mean 9 ± 4.13) participated in the study. Participants were classified into three OI type groups (I-2 cases, III-31 cases and IV-35 cases). Clinical examination and an orthopantomogram were used to obtain prevalences and associations of DI, caries status, malocclusion, crossbite, open bite, eruption, impaction and missing teeth with OI. The prevalence of DI among OI patients was 47.1%, more common in OI type III than type IV. The yellow-brown discoloration type was more vulnerable to attrition than the opalescent-grey one in the primary dentition. OI seemed not to have a high risk of caries; the prevalence of caries was 69.1%. A high incidence of malocclusion, crossbite and open bite was observed. In-depth oral information would provide valuable data for better dental management in OI patients. Parents and general doctors should pay more attention to dental care to prevent caries and premature tooth loss.
PubMed: 33925433
DOI: 10.3390/dj9050049 -
Revista Medica de Chile Dec 2020Osteogenesis imperfecta (OI) is a rare group of genetic disorders affecting connective tissue, with consequent bone fragility, frequent fractures and skeletal deformity....
BACKGROUND
Osteogenesis imperfecta (OI) is a rare group of genetic disorders affecting connective tissue, with consequent bone fragility, frequent fractures and skeletal deformity. Depending on the type, patients can have blue sclera, dentinogenesis imperfecta, and hearing loss.
AIM
To determine the frequency, type and audiometric characteristics of hearing loss in a group of patients with OI.
MATERIAL AND METHODS
A prospective cohort study was completed. A clinical and diagnostic hearing evaluation with tympanometry, acoustic stapedial reflex, pure-tone and speech audiometry were performed.
RESULTS
Thirty patients completed the study; mean age of 22 years (range 6-63 years). Sixty seven percent had a type I OI. Overall, nine (30%) patients had hearing loss (15/60 ears). Of these, six had bilateral hearing loss. Of the 15 affected ears, six showed conductive hearing loss, five sensorineural hearing loss, and four mixed hearing loss. Patients with hearing loss were older than patients with normal hearing. Only one pediatric patient developed hearing loss. Of the ears without hearing loss, 13% did not have an acoustic stapedial reflex.
CONCLUSIONS
In this group of patients with OI, 30% had hearing loss and among those ears with normal hearing, 13% did not have an acoustic stapedial reflex. Patients with OI should be monitored for hearing loss.
Topics: Adolescent; Adult; Audiometry, Pure-Tone; Child; Deafness; Hearing Loss; Humans; Middle Aged; Osteogenesis Imperfecta; Prospective Studies; Young Adult
PubMed: 33844744
DOI: 10.4067/S0034-98872020001201781 -
Molecular Genetics & Genomic Medicine Jun 2021Osteogenesis imperfecta (OI) is a rare heritable bone disorder that is characterised by increased bone fragility and recurrent fractures. To date, only 19 OI patients...
BACKGROUND
Osteogenesis imperfecta (OI) is a rare heritable bone disorder that is characterised by increased bone fragility and recurrent fractures. To date, only 19 OI patients have been reported, as caused by BMP1 gene mutations, worldwide. Here, we report a patient with a BMP1 gene mutation to explore the relationship between genotype and phenotype, and the patient was followed up for 4 years.
METHODS
Detailed clinical features were collected, and BMP1 mutational analysis was performed by next-generation sequencing and Sanger sequencing.
RESULTS
The patient had recurrent fractures, low bone mass, bone deformities and growth retardation but did not have hearing loss or dentinogenesis imperfecta. Next-generation sequencing and Sanger sequencing revealed a heterozygous novel missense variant (c.362C>T in exon 3, p.Ala121Val) and a heterozygous novel deletion mutation (c.1252delA in exon 10, p.Ser418AlafsX22). The parents of the proband were heterozygous carriers of these mutations. The patient received regular weekly treatment of 70 mg oral alendronate for 3 years, and her BMD Z-score for the femur significantly increased from -1.3 to 0.9 at L1-4 and from -1.7 to -0.1. She had no fracture during 4 years of follow-up.
CONCLUSION
We discovered two heterozygous novel mutations in an OI patient with BMP1 gene mutations, expanding the spectrum of gene mutations in OI.
Topics: Alendronate; Bone Density Conservation Agents; Bone Morphogenetic Protein 1; Child; Female; Homozygote; Humans; Mutation, Missense; Osteogenesis Imperfecta
PubMed: 33818922
DOI: 10.1002/mgg3.1676 -
Journal of Dentistry Jun 2021A better understanding of the microstructure and mechanical properties of enamel and dentine may enable practitioners to apply the current adhesive dentistry protocols... (Review)
Review
OBJECTIVES
A better understanding of the microstructure and mechanical properties of enamel and dentine may enable practitioners to apply the current adhesive dentistry protocols to clinical cases involving dentine disorders (dentinogenesis imperfecta or dentine dysplasia).
DATA/SOURCES
Publications (up to June 2020) investigating the microstructure of dentine disorders were browsed in a systematic search using the PubMed/Medline, Embase and Cochrane Library electronic databases. Two authors independently selected the studies, extracted the data in accordance with the PRISMA statement, and assessed the risk of bias with the Critical Appraisal Checklist. A Mann-Whitney U test was computed to compare tissues damage related to the two dentine disorders of interest.
STUDY SELECTION
From an initial total of 642 studies, only 37 (n = 164 teeth) were included in the present analysis, among which 18 investigating enamel (n = 70 teeth), 15 the dentine-enamel junction (n = 62 teeth), and 35 dentine (n = 156 teeth). Dentine is damaged in cases of dentinogenesis imperfecta and osteogenesis imperfecta (p = 2.55E-21 and p = 3.99E-21, respectively). These studies highlight a reduction in mineral density, hardness, modulus of elasticity and abnormal microstructure in dentine disorders. The majority of studies report an altered dentine-enamel junction in dentinogenesis imperfecta and in osteogenesis imperfecta (p = 6.26E-09 and p = 0.001, respectively). Interestingly, enamel is also affected in cases of dentinogenesis imperfecta (p = 0.0013), unlike to osteogenesis imperfecta (p = 0.056).
CONCLUSIONS
Taking into account all these observations, only a few clinical principles may be favoured in the case of adhesive cementation: (i) to preserve the residual enamel to enhance bonding, (ii) to sandblast the tooth surfaces to increase roughness, (iii) to choose a universal adhesive and reinforce enamel and dentine by means of infiltrant resins. As these recommendations are mostly based on in vitro studies, future in vivo studies should be conducted to confirm these hypotheses.
Topics: Dental Cements; Dental Enamel; Dentin; Hardness; Tooth
PubMed: 33798638
DOI: 10.1016/j.jdent.2021.103654 -
JBMR Plus Mar 2021(transport and Golgi organization-1 homolog) encodes a transmembrane protein, which is located at endoplasmic reticulum (ER) exit sites where it binds bulky cargo, such...
(transport and Golgi organization-1 homolog) encodes a transmembrane protein, which is located at endoplasmic reticulum (ER) exit sites where it binds bulky cargo, such as collagens, in the lumen and recruits membranes from the ER-Golgi intermediate compartment (ERGIC) to create an export route for cargo secretion. Mice lacking (murine TANGO1 orthologue) show defective secretion of numerous procollagens and lead to neonatal lethality due to insufficient bone mineralization. Recently, aberrant expression of truncated TANGO1 in humans has been shown to cause a mild-to-moderate severe collagenopathy associated with dentinogenesis imperfecta, short stature, skeletal abnormalities, diabetes mellitus, and mild intellectual disability. We now show for the first time that complete loss of TANGO1 results in human embryonic lethality with near-total bone loss and phenocopies the situation of mice. Whole-exome sequencing on genomic DNA (gDNA) of an aborted fetus of Indian descent revealed a homozygous 4-base pair (4-bp) deletion in that is heterozygously present in both healthy parents. Parental fibroblast studies showed decreased TANGO1 mRNA expression and protein levels. Type I collagen secretion and extracellular matrix organization were normal, supporting a threshold model for clinical phenotype development. As such, our report broadens the phenotypic and mutational spectrum of -related collagenopathies, and underscores the crucial role of TANGO1 for normal bone development, of which deficiency results in a severe-to-lethal form of osteochondrodysplasia. © 2021 American Society for Bone and Mineral Research © 2020 The Authors. published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
PubMed: 33778321
DOI: 10.1002/jbm4.10451 -
British Dental Journal Mar 2021Introduction Molar-incisor hypomineralisation (MIH) affects one in six children in the UK. For the majority of patients who have mild MIH, this should be managed in...
Introduction Molar-incisor hypomineralisation (MIH) affects one in six children in the UK. For the majority of patients who have mild MIH, this should be managed in primary care.Aims To assess UK-based general dental practitioners' (GDPs) ability to diagnose MIH when presented with multiple clinical vignettes.Design An electronic vignette survey was designed with use of clinical photographs - six cases had MIH and/or hypomineralised second primary molars (HSPMs) (seven possible diagnoses). Four control cases showing caries, fluorosis, amelogenesis imperfecta and dentinogenesis imperfecta were also included. Participants were UK-based GDPs. The survey was distributed by email and across social media platforms. Data collection occurred between February and May 2019.Results Seventy-six GDPs completed the survey; 68.4% (n = 52) of participants were female and 83% (n = 63) of participants graduated after the year 2000. The number of accurate diagnoses for each case were as follows - mild MIH (molars/incisors) 65.79%; mild MIH (molars only) 3.95%; HSPM and MIH (HSPM result) 0%; HSPM and MIH (MIH result) 50%; severe MIH (post-eruptive breakdown) 63.16%; severe MIH (caries) 31.58%; HSPM 3.95%.Conclusion GDPs are able to accurately diagnose MIH best when both incisors and molars are affected and caries is not present.
PubMed: 33762697
DOI: 10.1038/s41415-021-2735-3 -
Bone Jun 2021Dental anomalies in Osteogenesis imperfecta (OI), such as tooth discoloration, pulp obliteration (calcified dental pulp space), and taurodontism (enlarged dental pulp...
INTRODUCTION
Dental anomalies in Osteogenesis imperfecta (OI), such as tooth discoloration, pulp obliteration (calcified dental pulp space), and taurodontism (enlarged dental pulp space) vary between and within patients. To better understand the associations and variations in these anomalies, a cross-sectional study was designed to analyze the dental phenotype in OI patients at the individual tooth type.
METHOD
A cohort of 171 individuals with OI type I, III and IV, aged 3-55 years, were recruited and evaluated for tooth discoloration, pulp obliteration, and taurodontism at the individual tooth level, using intraoral photographs and panoramic radiographs.
RESULTS
Genetic variants were identified in 154 of the participants. Patients with Helical α1 and α2 glycine substitutions presented the highest prevalence of tooth discoloration, while those with α1 Haploinsufficiency had the lowest (<10%). C-propeptide variants did not cause discoloration but resulted in the highest pulp obliteration prevalence (~%20). The prevalence of tooth discoloration and pulp obliteration was higher in OI types III and IV and increased with age. Tooth discoloration was mainly observed in teeth known to have thinner enamel (i.e. lower anterior), while pulp obliteration was most prevalent in the first molars. A significant association was observed between pulp obliteration and tooth discoloration, and both were associated with a lack of occlusal contact. Taurodontism was only found in permanent teeth and affected mostly first molars, and its prevalence decreased with age.
CONCLUSION
The dental phenotype evaluation at the tooth level revealed that different genetic variants and associated clinical phenotypes affect each tooth type differently, and genetic variants are better predictors of the dental phenotype than the type of OI. Our results also suggest that tooth discoloration is most likely an optical phenomenon inversely proportional to enamel thickness, and highly associated with pulp obliteration. In turn, pulp obliteration is proportional to patient age, it is associated with malocclusion and likely related to immature progressive dentin deposition. Taurodontism is an isolated phenomenon that is probably associated with delayed pulpal maturation.
Topics: Cross-Sectional Studies; Dentinogenesis Imperfecta; Humans; Osteogenesis Imperfecta; Phenotype; Tooth
PubMed: 33741542
DOI: 10.1016/j.bone.2021.115917 -
Oral Surgery, Oral Medicine, Oral... Jun 2021Dentinogenesis imperfecta (DI) requires dental treatment. This study investigated the characteristics of DI teeth associated with osteogenesis imperfecta (OI) and COL1A2...
OBJECTIVE
Dentinogenesis imperfecta (DI) requires dental treatment. This study investigated the characteristics of DI teeth associated with osteogenesis imperfecta (OI) and COL1A2 mutations.
STUDY DESIGN
Whole exome and Sanger sequencing were performed. Three primary teeth (called "OIDI teeth") obtained from 3 unrelated COL1A2 patients were investigated and compared with 9 control teeth from age-matched healthy individuals using colorimetry, micro-computed tomography, Knoop microhardness, energy dispersive X-ray spectroscopy, scanning electron microscopy, and histology.
RESULTS
All patients were identified with heterozygous glycine substitutions in COL1A2. The COL1A2 mutations, c.1531G>T and c.2027G>T, were de novo, whereas c.3106G>C was inherited. OIDI1, 2, and 3 teeth had a substantial decrease in dentin microhardness and lightness. OIDI2 enamel microhardness was significantly reduced, whereas OIDI1 and 3 had enamel microhardness comparable to that of control individuals. The OIDI1 pulp cavity was large; OIDI2 was narrow; and OIDI3 was obliterated. OIDI1 and 3 had significantly higher carbon levels than those in control individuals. Numerous ectopic calcified masses, sparse and obstructed dentinal tubules, dentin holes, and collagen disorientation were observed.
CONCLUSIONS
OIDI teeth had reduced lightness and variable pulp morphology. Weak dentin, mineral disproportion, and abnormal ultrastructure could contribute to the brittleness of OIDI teeth and adhesive restoration failure. Here, we expand the phenotypic spectrum of COL1A2 mutations and raise awareness among dentists seeing patients with OI.
Topics: Collagen Type I; Dentin; Dentinogenesis Imperfecta; Humans; Mutation; Osteogenesis Imperfecta; X-Ray Microtomography
PubMed: 33737018
DOI: 10.1016/j.oooo.2021.01.003 -
Frontiers in Cell and Developmental... 2021Hypoxia is a state of inadequate supply of oxygen. Increasing evidence indicates that a hypoxic environment is strongly associated with abnormal organ development....
Hypoxia is a state of inadequate supply of oxygen. Increasing evidence indicates that a hypoxic environment is strongly associated with abnormal organ development. Oxygen nanobubbles (ONBs) are newly developed nanomaterials that can deliver oxygen to developing tissues, including hypoxic cells. However, the mechanisms through which nanobubbles recover hypoxic tissues, such as developing tooth germs remain to be identified. In this study, tooth germs were cultured in various conditions: CO chamber, hypoxic chamber, and with 20% ONBs for 3 h. The target stages were at the cap stage (all soft tissue) and bell stage (hard tissue starts to form). Hypoxic tooth germs were recovered with 20% ONBs in the media, similar to the tooth germs incubated in a CO chamber (normoxic condition). The tooth germs under hypoxic conditions underwent apoptosis both at the cap and bell stages, and ONBs rescued the damaged tooth germs in both the cap and bell stages. Using kidney transplantation for hard tissue formation , amelogenesis and dentinogenesis imperfecta in hypoxic conditions at the bell stage were rescued with ONBs. Furthermore, glucose uptake by tooth germs was highly upregulated under hypoxic conditions, and was restored with ONBs to normoxia levels. Our findings indicate that the strategies to make use of ONBs for efficient oxygen targeted delivery can restore cellular processes, such as cell proliferation and apoptosis, glucose uptake, and hypomineralization in hypoxic environments.
PubMed: 33659251
DOI: 10.3389/fcell.2021.626224