•SHED-Exos mitigated glucocorticoid-induced damage in BMSCs.•SHED-Exos’ impact on BMSC signaling and gene expression was analyzed.•SHED-Exos suppressed HGF, ITGB8 and IL7 expression; enhanced EFNA1 ...expression.,
Steroid-induced osteonecrosis of the femoral head (SONFH) is a disease characterized by a collapsed femoral head caused by the overuse of glucocorticoids. Dysfunction of bone marrow mesenchymal stem cells (BMSCs) is an important pathological feature of SONFH. In this study, we investigated whether exosomes from SHEDs (stem cells from human exfoliated deciduous teeth) have a therapeutic effect on glucocorticoid-induced inhibition of proliferation and osteogenesis in BMSCs, and elucidated the underlying mechanisms involved.
Primary dental pulp cells were isolated and cultured from human deciduous tooth pulp, SHEDs were isolated and purified by the limiting dilution method and exosomes were isolated from the supernatants of SHEDs by ultracentrifugation. The cell surface markers CD31, CD34, CD45, CD73, CD90 and CD105 were detected by flow cytometry. A Cell-Counting-Kit-8 assay was used to detect cell activity. ALP and Alizarin Red staining were used to identify osteogenic differentiation ability, and exosomes were identified using transmission electron microscopy, NanoFCM and Western blotting. PKH67 fluorescence was used to track the uptake of exosomes by BMSCs. Transcriptome analysis combined with quantitative real-time PCR was used to explore the underlying mechanism involved.
Exosomes secreted by SHEDs can be endocytosed by BMSCs, and can partially reverse the inhibitory effects of glucocorticoids on the viability and osteogenic differentiation of BMSCs. Transcriptome sequencing analysis revealed that the differentially expressed mRNAs regulated by SHED-derived exosomes were enriched mainly in signaling pathways such as the apoptosis pathway, the PI3K-Akt signaling pathway, the Hippo signaling pathway and the p53 signaling pathway. qPCR showed that SHED-derived exosomes reversed the dexamethasone-induced upregulation of HGF and ITGB8 expression and the inhibition of EFNA1 expression, but further increased the dexamethasone-induced downregulation of IL7 expression. In conclusion, SHED-derived exosomes partially reversed the inhibitory effects of glucocorticoids on BMSC proliferation and osteogenesis by inhibiting the expression of HGF, ITGB8 and IL7, and upregulating the expression of EFNA1.
Sparse research exists on predictors of element concentrations measured in deciduous teeth.
To estimate associations between maternal/child characteristics, elements measured in home tap water during ...pregnancy and element concentrations in the dentin of shed deciduous teeth.
Our analysis included 152 pregnant person-infant dyads followed from the second trimester through the end of the first postnatal year from the New Hampshire Birth Cohort Study. During pregnancy and early infancy, we collected dietary and sociodemographic information via surveys, measured elements in home tap water, and later collected naturally exfoliated teeth from child participants. We measured longitudinal deposition of elements in dentin using LA-ICP-MS. Multivariable linear mixed models were used to estimate associations between predictors and dentin element concentrations.
We measured 12 elements in dentin including those previously reported (Ba, Mn, Pb, Sr, Zn) and less frequently reported (Al, As, Cd, Cu, Hg, Li, and W). A doubling of Pb or Sr concentrations in water was associated with higher dentin Pb or Sr respectively in prenatally formed 9% (95%CI: 3%, 15%); 3% (1%, 6%) and postnatally formed 10% (2%, 19%); 6% (2%, 10%) dentin. Formula feeding from birth to 6 weeks or 6 weeks to 4 months was associated with higher element concentrations in postnatal dentin within the given time period as compared to exclusive human milk feeding: Sr: 6 weeks: 61% (36%, 90%) and 4 months: 85% (54%, 121%); Ba: 6 weeks: 35% (3.3%, 77%) and 4 months: 42% (10%, 83%); and Li: 6 weeks: 61% (33%, 95%) and 4 months: 58% (31%, 90%).
These findings offer insights into predictors of dentin elements and potential confounders in exposure-health outcome relationships during critical developmental periods.
•Sparse research exists on predictors of element concentrations in deciduous teeth.•We measured elements in teeth from a prospective rural pregnancy cohort.•Water lead (Pb) and strontium (Sr) were predictors of Pb and Sr in teeth.•Any formula use associated with higher barium, lithium and Sr in postnatal dentin.
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•A multidisciplinary approach based on RMS, SEM, EDS and VMH was exploited.•Structural and chemical differences were found in permanent and deciduous teeth.•A good linear correlation ...between RMS, VMH and EDS data was found.•RMS is a new diagnostic tool to identify anomalies in calcified dental tissues.•The deeper knowledge of teeth structure helps clinicians in dental material choice.
Teeth are characterized by a specific chemical composition and microstructure, which are related to their nature, permanent and deciduous, and to the sides, lingual and vestibular. Deeper knowledge in this topic could be useful in clinical practice to develop new strategies in restorative dentistry and in the choice of materials with the best performances. In this study, Raman MicroSpectroscopy (RMS), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS), and Vickers MicroHardness (VMH) were exploited to: (1) identify the microstructure and the chemical/elemental composition of permanent and deciduous human teeth, also characterizing their lingual and vestibular sides, and (2) validate a new multidisciplinary analytical approach, for obtaining multiple information on calcified tissues. All applied techniques evidenced differences between permanent and deciduous teeth both in the lingual and vestibular sides. In particular, scanning electron micrographs identified areas with an irregular appearance in the vestibular and lingual sides, which presented also different VMH values. Moreover, RMS and EDS displayed a different chemical/elemental composition in outer and inner enamel and dentin, in terms of Mineral/Matrix, Crystallinity, Carbonates/phosphates, and concentrations by weight (%) of calcium, phosphorous, carbon, magnesium, and sodium. A good linear correlation was found between RMS spectral profiles and EDS and VMH measurements, suggesting that RMS may be considered a useful and non-destructive diagnostic tool for obtaining multiple information on calcified tissues.
Background: The cause of cavities is initially due to roughness on the tooth surface, requiring fluoride varnish to prevent caries, as the varnish applies a fluoride compound to the tooth surface. ...Fluoride varnish reacts with the tooth enamel surface to form calcium fluoride and fluorapatite, thus making the enamel surface more resistant to demineralization and damage. Purpose: This study aims to compare the roughness of tooth enamel surfaces among three fluoride varnishes under acidic conditions. Methods: The research method uses three fluoride varnish materials: sodium fluoride 5% + tricalcium phosphate, calcium fluoride, and sodium fluoride 5% + casein phosphopeptide-amorphous calcium phosphate 2%. Samples of 81 teeth were divided into three groups (Group 1 without fluoride varnish application, Group 2 application of fluoride varnish with pH 3, and Group 3 application of fluoride varnish with pH 5). The teeth were tested before and after application of the varnishes using the scanning electron microscope and surface roughness tests. Results: The results showed a significant difference in the mean surface roughness of the enamel of the anterior deciduous teeth tested with fluoride varnish. The before and after comparisons in the pH 3 and pH 5 groups were very significant (p-value 0.000). The comparison results in each pH group after fluoride varnish administration showed no significant difference (pH 3 p-value 0.074 and pH 5 p-value 0.196). The tooth surfaces appear to be rougher after administration of an all-acid solution. Conclusion: There is a difference in surface roughness of primary teeth after being given fluoride varnish in low pH 3 immersion for 24 hours.
This paper investigates whether deciduous upper molars and lower canines have sexual dimorphic features, exploring these teeth' dimensions and the presence of Zuckerkandl’s tubercle and Carabelli’s ...cusp on the first and second upper molars.
We analyzed 64 pairs of dental plaster casts from 34 females and 30 males aged between 3 and 12 years. We measured the first and second deciduous upper molars and the lower deciduous canines (maximum mesiodistal and buccolingual length), and we registered the presence of the Zuckerkandl’s tubercle and the Carabelli’s cusp on the first and second upper molars, respectively.
Regarding the differentiation between sexes using Carabelli’s cusp and Zuckerkandl’s tubercle, the classification was not independent of Carabelli’s cusp presence only for tooth 65 (p = 0.035). In all other teeth, whether for Carabelli’s cusp or Zuckerkandl’s tubercle, their presence was similar for both sexes. There were statistically significant differences between sexes (p < 0.05) for the buccolingual measurements of both upper second molars, the first right upper molar, and the right canine. The developed model allowed for a 64.1% accuracy in sex estimation.
The study suggests that while Carabelli’s cusp and Zuckerkandl’s tubercle in upper deciduous molars don't consistently differ between sexes, tooth size, particularly the buccolingual measurements of certain teeth, including upper deciduous molars and lower canines, may provide a more reliable criterion for sex estimation. The developed model depicted moderate accuracy, underscoring the need for a multifactorial approach when estimating sex from skeletal remains. It suggests that while dental features can contribute to sex estimation, they should be used in conjunction with other skeletal or molecular markers to improve accuracy.
•Carabelli’s cusp in the upper left second molar is a sexual dimorphic feature.•Zuckerkandl’s tubercle in the first upper molar doesn’t show sexual dimorphism.•The buccolingual dimension shows more sexual dimorphism than the mesiodistal one.•All measurements in the upper second deciduous molar showed sexual dimorphism.•Our model allowed for 64.1% of correct sex classifications.
Mesenchymal stem cells (MSCs) are used clinically in tissue engineering and regenerative medicine. The proliferation and osteogenic differentiation potential of MSCs vary according to factors such as ...tissue source and cell population heterogeneity. Dental tissue has received attention as an easily accessible source of high-quality stem cells. In this study, we compared the in vitro characteristics of dental pulp stem cells from deciduous teeth (SHED), human dental pulp stem cells (hDPSCs), and human bone marrow mesenchymal stem cells (hBMSCs).
SEHD and hDPSCs were isolated from dental pulp and analyzed in comparison with human bone marrow (hBM)MSCs. Proliferative capacity of cultured cells was analyzed using a bromodeoxyuridine immunoassay and cell counting. Alkaline phosphatase (ALP) levels were monitored to assess osteogenic differentiation. Mineralization was evaluated by alizarin red staining. Levels of bone marker mRNA were examined by real-time PCR analysis.
SHED were highly proliferative compared with hDPSCs and hBMSCs. SHED, hDPSCs, and hBMSCs exhibited dark alizarin red staining on day 21 after induction of osteogenic differentiation, and staining of hBMSCs was significantly higher than that of SHED and hDPSCs by spectrophotometry. ALP staining was stronger in hBMSCs compared with SHED and hDPSCs, and ALP activity was significantly higher in hBMSCs compared with SHED or hDPSCs. SHED showed significantly higher expression of the Runx2 and ALP genes compared with hBMSCs, based on real-time PCR analysis. In bFGF, SHED showed significantly higher expression of the basic fibroblast growth factor (bFGF) gene compared with hDPSCs and hBMSCs.
SHED exhibited higher proliferative activity and levels of bFGF and BMP-2 gene expression compared with BMMSCs and DPSCs. The ease of harvesting cells and ability to avoid invasive surgical procedures suggest that SHED may be a useful cell source for application in bone regeneration treatments.
•We compared the in vitro characteristics of dental pulp stem cells from deciduous teeth (SHED), human dental pulp stem cells (hDPSCs), and human bone marrow mesenchymal stem cells (hBMSCs).•SHED exhibit greater proliferative potential than hDPSCs and hBMSCs.•SHED exhibited higher proliferative activity and levels of bFGF and BMP-2 gene expression compared with BMMSCs and DPSCs. The ease of harvesting cells and ability to avoid invasive surgical procedures suggest that SHED may be a useful cell source for application in bone regeneration treatments.
Pulp therapy in primary teeth has been performed using various instrumentation techniques. However, the conventional instrumentation technique used for root canal preparation in primary teeth is hand ...instrumentation. Various Nickel-Titanium (Ni-Ti) instruments are available to perform efficient root canal preparation in primary teeth. These Ni-Ti instruments has been designed to aid in better root canal preparation in permanent teeth but are rarely used in primary teeth. It is necessary to assess the feasibility of using these adult rotary files with a modified sequence in primary teeth.
To compare the quality of obturation and instrumentation time during root canal preparation using hand files and modified rotary file systems in primary molars.
Forty-five primary mandibular molars were randomly assigned to three experimental groups (n=15). Group I was instrumented using k-hand files, Group II with S2 ProTaper universal file and Group III with 0.25 tip 4% taper K3 rotary file. Standardized digital radiographs were taken before and after root canal instrumentation. Root canal preparation time was also recorded. Statistical analysis of the obtained data was done using SPSS Software version 17.0. An intergroup comparison of the instrumentation time and the quality of obturation was done using ANOVA and Chi-square test with the level of significance set at 0.05.
No significant differences were noted with regard to the quality of obturation (p=0.791). However, a statistically significant difference was noted in the instrumentation time between the three groups (p<0.05). ProTaper rotary system had significantly lesser instrumentation time when compared to that of K3 rotary system and hand file system.
The hand files, S2 ProTaper Universal and K3 0.25 tip 4% taper files systems performed similarly with respect to the quality of obturation. There was a significant difference in instrumentation time with manual instrumentation compared to the modified rotary file systems in primary teeth.
BackgroundHuman teeth develop sequentially and symmetrically in both halves of the jaws. Disorders of tooth development and eruption can be local or generalized. The symmetry comparison of tooth ...development is an essential measuring point to assess dentition. The aim of this study was the development of an easy-to-apply score that represents the tooth development of one side of the jaw to carry out side-specific development comparisons. Material and MethodsThe stages of development and the state of health of the teeth were determined on orthopantomograms of 59 healthy children and adolescents applying acknowledged developmental standards of teeth. The individual stages of tooth development on one side of the jaw were combined into a numerical score. The sum score of each jaw side was compared. ResultsThe dental developmental score reveals the side differences of tooth development are small in children and adolescents with mixed dentition (n.s.). The change of teeth starts earlier in females. ConclusionsThe presented score enables an easily applicable examination of the symmetry of tooth development in mixed dentition. Potential applications of the Score are to examine the influence of unilaterally manifest dento-skeletal developmental disorders on the change of teeth and the influence of deviating individual tooth development on neighboring teeth on one side. Key words:Dentition, development, symmetry, permanent teeth, deciduous teeth, oral health.Dentition, development, symmetry, permanent teeth, deciduous teeth, oral health.
Background and Aims: There is a traditional belief that the primary teeth can be replaced by permanent teeth and preserving them is not important. The aim of this study was to evaluate the knowledge ...and attitude of parents of preschool and elementary school children referring to the Specialty Clinic of Isfahan University of Medical Sciences and Imam Hossein pediatric hospital about the importance of preserving deciduous teeth and related factors. Materials and Methods: This descriptive cross-sectional study was performed on 323 parents of preschool and elementary school children referred to the special clinic of Isfahan University of Medical Sciences and Imam Hossein Pediatric hospital. The data collection method was a questionnaire and face-to-face interview. The questionnaire was made, it consisted of 21 multiple-choice questions and descriptive questions. Data were analyzed using descriptive statistics tests and analytical tests such as t-test and Pearson correlation coefficient. Results: The mean score of knowledge of parents was 37.5 with a standard deviation of 16.9, the mean score of attitude was 55.8 with a standard deviation of 11.1 and the mean score of performance was 41.8 with a standard deviation of 15.6 out of 100. Pearson correlation coefficient showed that there was a direct relationship between knowledge, attitude, and performance scores (P<0.001). Parents' knowledge score was directly related to the mothers' and fathers' ages (P<0.001). Conclusion: According to the results, parents' awareness of the importance of the preservation of deciduous teeth and related factors is poor, their attitudes are neutral and their performance is poor to moderate. It is suggested to improve treatment facilities available for children in the family and to educate parents about the preservation of deciduous teeth.
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