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Operative Dentistry May 2023The objective was to investigate the radiopacity of 11 commercial posterior restorative materials by establishing their mean gray values (MGVs) and comparing them with...
BACKGROUND
The objective was to investigate the radiopacity of 11 commercial posterior restorative materials by establishing their mean gray values (MGVs) and comparing them with dental hard tissues.
METHODS AND MATERIALS
Five-disc specimens were prepared for each of the following materials: Cerasmart 270 CAD/CAM block A3LT (CS), Amalgam (A), Ketac Molar A3 (KM), Cention-N A2 (CN), G-aenial Universal Flo AO2 (GO2) and A2 (G2), Ever-X Flow Dentine (EXD) and Bulk (EXB) shades, Equia Forte HT Fil A2 (EF2) and A3 (EF3), and Equia Fil A3 (E3). Freshly extracted maxillary premolar teeth were used as a control. The MGVs of specimens and a 10-step aluminum stepwedge (Al) were measured with Adobe Photoshop. ANOVA and Dunnett T3 tests were used to assess the significance of the differences (α=0.05).
RESULTS
Statistically significant differences were revealed between some of the groups. Amalgam had the highest radiopacity. The radiopacity of dentin and CS were close to that of 1 mm Al. G2, KM, GO2, EXB, and EXD showed higher mean radiopacity than dentin. Enamel had a radiopacity equivalent to 2 mm Al. CN, EF2, and E3 had higher mean radiopacity than enamel.
CONCLUSIONS
All materials met the ISO requirements. Alkasite and reinforced glass ionomer restoratives demonstrated higher mean radiopacity than the posterior flowable composites. Material shades did not affect the radiopacity.
Topics: Dentin; Composite Resins; Dental Materials; Dental Enamel; Materials Testing
PubMed: 37079911
DOI: 10.2341/22-042-L -
Oral Diseases Apr 2018To explore the mineral features of dentin and cementum in hypoplastic Amelogenesis imperfecta AI teeth.
OBJECTIVE
To explore the mineral features of dentin and cementum in hypoplastic Amelogenesis imperfecta AI teeth.
MATERIALS AND METHODS
Forty-four (44) teeth cleaned and free of caries were used: 20 control and 24 affected by hypoplastic amelogenesis imperfecta. Thirty-two teeth were studied by pQCT, cut in sections, and analyzed under microradiography, polarized light microscopy, and confocal Raman spectroscopy. Eight teeth were observed under scanning electron microscope. Four teeth were used for an X-ray diffraction. The mineral density data were analyzed statistically with the Mann-Whitney U test, using GraphPad InStat software.
RESULTS
Both coronal dentin and radicular dentin were less mineralized in AI teeth when compared to control (respectively 6.2% and 6.8%; p < .001). Root dentinal walls were thin and irregular, while the cellular cementum layers were thick, reaching sometimes the cervical region of the tooth. Regular dentinal tubules and sclerotic dentin areas were noticed. Partially tubular or cellular dysplastic dentin and hyper-, normo-, or hypomineralized areas were noticed in the inter-radicular areas of hypoplastic AI teeth. The main mineral component was carbonate hydroxyapatite as explored by Raman spectroscopy and X-ray diffraction.
CONCLUSIONS
Dentin and cementum in hypoplastic AI teeth are (i) hypomineralized, (ii) constituted of carbonate hydroxyapatite, and (iii) of non-homogenous structure.
Topics: Adolescent; Adult; Amelogenesis Imperfecta; Dental Cementum; Dentin; Humans; Microradiography; Microscopy, Electron, Scanning; Microscopy, Polarization; Minerals; Spectrum Analysis, Raman; Tomography, X-Ray Computed; Tooth; X-Ray Diffraction; Young Adult
PubMed: 28771955
DOI: 10.1111/odi.12724 -
Journal of the Mechanical Behavior of... May 2018Bonding to demineralized dentin of a diseased tooth has shown to be a significant clinical issue. This study evaluated the effect of 0.2% NaF-(NaF), MI...
Bonding to demineralized dentin of a diseased tooth has shown to be a significant clinical issue. This study evaluated the effect of 0.2% NaF-(NaF), MI Paste™-(CPP-ACP) and the self-assembling peptide 'P' (Ace-QQRFEWEFEQQ-NH) contained in Curodont™ Repair, have on microtensile bond strength-(µTBS) of two different adhesive systems (Adper™ Single Bond-(SB) or Clearfil™ SE Bond (CSE)) and wettability of demineralized dentin slices after remineralising agents were applied. The highest µTBS were found for the demineralized dentin-(DD) treated with CPP-ACP; both adhesives systems (p < 0.05) did not significantly difference from P treatment associated with SB, and also presented higher values than sound dentin-(SD/SB) (p < 0.01). DD treated with P associated with CSE did not differ from DD/CSE (p > 0.05). The NaF treatment associated with CSE recovered the bond strength values of SD/CSE and associated with CSE demonstrated lower µTBS than other groups, although significantly higher than DD (p < 0.05). P and CPP-ACP increased significantly the wettability of demineralized dentin (p < 0.05); etching acid improved wettability for all groups (p < 0.05), whilst NaF did not affect the wettability of demineralized dentin (p > 0.05). Morphological analysis of the dentin surface and dentin-resin interface revealed unique features of the applied remineralizing agent. The results indicated that self-assembling peptide P associated with SB and CPP-ACP associated with SB or CSE significantly enhanced the bond strength to demineralized dentin (p < 0.05). We conclude that by modifying the dentine surface and restoring conditions found on sound dentin, this can enhance the interfacial bonding.
Topics: Amino Acid Sequence; Biomechanical Phenomena; Calcium Phosphates; Dentin; Humans; Mechanical Phenomena; Minerals; Oligopeptides; Sodium Fluoride
PubMed: 29550716
DOI: 10.1016/j.jmbbm.2018.03.007 -
Journal of Dentistry Aug 2014To evaluate, in vitro, the effects of ionizing radiation on the mechanical and micro-morphological properties of enamel and dentin of permanent teeth. (Comparative Study)
Comparative Study
OBJECTIVES
To evaluate, in vitro, the effects of ionizing radiation on the mechanical and micro-morphological properties of enamel and dentin of permanent teeth.
METHODS
Enamel and dentin microhardness (n=12 hemi-sections) was evaluated at three depths (superficial, middle and deep) prior to (control) and after every 10Gy radiation dose up to a cumulative dose of 60Gy by means of longitudinal microhardness. Data were analyzed using two-way analysis of variance and Tukey's test at a significance level of 5%. Enamel and dentin morphology was assessed by scanning electron microscopy (SEM) for semi-quantitative analysis (n=8 hemi-sections). Data were analyzed using Kruskal-Wallis and Dunn's or Fisher exact tests at a significance level of 5%.
RESULTS
The application of ionizing radiation did not change the overall enamel microhardness, although an increase in superficial enamel microhardness was observed. The micro-morphological analysis of enamel revealed that irradiation did not influence rod structure but interprismatic structure became more evident. Dentin microhardness decreased after 10, 20, 30, 50 and 60Gy cumulative doses (p<0.05) compared with non-irradiated dentin, mainly in the middle portion of the tissue. The micro-morphological analysis revealed fissures in the dentin structure, obliterated dentinal tubules and fragmentation of collagen fibers after 30 and 60Gy cumulative doses.
CONCLUSIONS
Although ionizing radiation did not affect the enamel microhardness of permanent teeth as a whole, an increase in superficial enamel microhardness was observed. Dentin microhardness decreased after almost all radiation doses compared with the control, with the greatest reduction of microhardness in the middle depth region. The morphological alterations on enamel and dentin structures increased with the increase of the radiation dose, with a more evident interprismatic portion, presence of fissures and obliterated dentinal tubules, and progressive fragmentation of the collagen fibers.
CLINICAL SIGNIFICANCE
This study shows that irradiation affects microhardness and micro-morphology of enamel and dentin of permanent teeth. The effects of gamma irradiation on dental substrate might contribute to increased risk of radiation tooth decay associated with salivary changes, microbiota shift and high soft and carbohydrate-rich food intake.
Topics: Cobalt Radioisotopes; Collagen; Dental Enamel; Dentin; Dose Fractionation, Radiation; Hardness; Humans; In Vitro Techniques; Microscopy, Electron, Scanning; Molar; Radiotherapy Dosage; Radiotherapy, High-Energy
PubMed: 24887361
DOI: 10.1016/j.jdent.2014.05.011 -
Dental Materials : Official Publication... Nov 2022Dentin microstructure undergoes changes with age and its materials properties degrade over time. In the present study, we investigate the coupled influence of increased...
OBJECTIVES
Dentin microstructure undergoes changes with age and its materials properties degrade over time. In the present study, we investigate the coupled influence of increased filled tubules and decreased materials properties on the fracture behavior of human dentin.
METHODS
We assume degraded materials properties are linked with increased advanced glycation end-products (AGEs) crosslinks in dentin tissue. We use morphological data of human molars to create 2D and 3D models of dentin microstructure, and utilize a phase field fracture framework to study crack growth trajectories. We construct aged dentin samples (i.e., filled tubules and degraded properties) and compare the fracture results with the samples without age-related changes.
RESULTS
The simulations show an increase in the number of filled tubules can deactivate the toughening mechanisms such as crack deflection and microcracking. In addition, filled tubules have adverse impacts on the ability of peritubular dentin to shield microcracking. We further show how the dentinal tubules' orientations affect the crack surface growth. We also investigate that an increase in the AGEs level can result in increased brittleness.
SIGNIFICANCE
The developed model and findings of the present study provide region-dependent information on crack growth trajectories as well as more understanding of crack surface growth at the presence of filled tubules.
Topics: Aged; Dentin; Humans; Molar
PubMed: 36184336
DOI: 10.1016/j.dental.2022.09.009 -
Journal of Dentistry Apr 2018This study aims to apply electrophoretic deposition (EPD) for occlusion of dentinal tubules in vitro and investigate its effect on tubule occlusion and shear bond...
OBJECTIVES
This study aims to apply electrophoretic deposition (EPD) for occlusion of dentinal tubules in vitro and investigate its effect on tubule occlusion and shear bond strength (SBS).
METHODS
Charged mesoporous silica nanoparticles (MSNs) were synthesized and characterized through field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and Fourier transform infrared (FT-IR) spectroscopy analyses. Thirty-nine sensitive dentin specimens were modeled and assigned randomly to three groups with different treatments (n = 13 each): group 1, immersion in the MSN suspension; and groups 2 and 3, anodic EPD with the specimen on the negative and positive electrode respectively. The effect of dentinal tubule occlusion was evaluated by dentin permeability test (n = 10 each) and FESEM examination (n = 3 each). Moreover, 18 specimens were grouped (n = 6 each) and treated in the same method. A resin stick was bonded onto each of the specimen using a self-etch adhesive (single bond universal) for SBS testing.
RESULTS
Negatively-charged MSNs were synthesized and characterized as small and well-dispersed particles. After the EPD treatment (group 3), the dentinal tubules were effectively occluded by MSNs, which infiltrated into the tubules at a depth of approximately 7-8 μm and tightly associated with the tubular inwalls. SBS was not significantly different among the three groups (P > 0.05).
CONCLUSIONS
Synthesized MSNs were deposited into dentinal tubules by EPD treatment without compromising dentin bond strength.
CLINICAL SIGNIFICANCE
Application of EPD is a new approach for occlusion of dentinal tubules and exhibits potential in the study of dentin hypersensitivity.
Topics: Bisphenol A-Glycidyl Methacrylate; Dental Occlusion; Dentin; Dentin Desensitizing Agents; Dentin Permeability; Dentin Sensitivity; Dynamic Light Scattering; Electrodes; Electrophoresis; Humans; In Vitro Techniques; Materials Testing; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanoparticles; Particle Size; Shear Strength; Silicon Dioxide; Surface Properties
PubMed: 29391182
DOI: 10.1016/j.jdent.2018.01.012 -
Journal of Dental Research Jul 2016If there is a partial loss of dentin, the exposed dentinal surface should be protected by an indirect pulp capping (IPC) procedure to preserve pulp vitality and prevent...
If there is a partial loss of dentin, the exposed dentinal surface should be protected by an indirect pulp capping (IPC) procedure to preserve pulp vitality and prevent symptoms of dentin hypersensitivity. In our previous study, copine7 (CPNE7) induced odontoblast differentiation in vitro and promoted dentin formation in vivo. The aim of this study was to investigate the possibility of IPC therapy using the CPNE7 protein at the exposed dentinal surface and the resulting effects on tertiary dentin formation in a beagle model. CPNE7 promoted mineralization of odontoblasts and had high calcium ion-binding capacity. The in vivo IPC model with canine teeth showed that regeneration of physiologic reactionary dentin with dentinal tubule structures was clearly observed beneath the remaining dentin in the CPNE7 group, whereas irregular features of reparative dentin were generated in the mineral trioxide aggregate (MTA) group. The CPNE7+MTA group also showed typical reactionary dentin without reparative dentin, showing synergistic effects of CPNE7 with MTA. A scanning electron microscopy analysis showed that dentinal tubules beneath the original dentin were occluded by the deposition of peritubular dentin in the CPNE7 and CPNE7+MTA groups, whereas those in the control group were opened. Therefore, CPNE7 may be able to serve as a novel IPC material and improve symptoms of dentin hypersensitivity.
Topics: Animals; Blotting, Western; Cell Movement; Cell Proliferation; Cells, Cultured; Dental Pulp Capping; Dentin; Dogs; Humans; Membrane Proteins; Odontoblasts; Real-Time Polymerase Chain Reaction
PubMed: 27013639
DOI: 10.1177/0022034516639919 -
PLoS Pathogens May 2024The role of bacteria in the etiology of dental caries is long established, while the role of fungi has only recently gained more attention. The microbial invasion of...
The role of bacteria in the etiology of dental caries is long established, while the role of fungi has only recently gained more attention. The microbial invasion of dentin in advanced caries especially merits additional research. We evaluated the fungal and bacterial community composition and spatial distribution within carious dentin. Amplicon 16S rRNA gene sequencing together with quantitative PCR was used to profile bacterial and fungal species in caries-free children (n = 43) and 4 stages of caries progression from children with severe early childhood caries (n = 32). Additionally, healthy (n = 10) and carious (n = 10) primary teeth were decalcified, sectioned, and stained with Grocott's methenamine silver, periodic acid Schiff (PAS) and calcofluor white (CW) for fungi. Immunolocalization was also performed using antibodies against fungal β-D-glucan, gram-positive bacterial lipoteichoic acid, gram-negative endotoxin, Streptococcus mutans, and Candida albicans. We also performed field emission scanning electron microscopy (FESEM) to visualize fungi and bacteria within carious dentinal tubules. Bacterial communities observed included a high abundance of S. mutans and the Veillonella parvula group, as expected. There was a higher ratio of fungi to bacteria in dentin-involved lesions compared to less severe lesions with frequent preponderance of C. albicans, C. dubliniensis, and in one case C. tropicalis. Grocott's silver, PAS, CW and immunohistochemistry (IHC) demonstrated the presence of fungi within carious dentinal tubules. Multiplex IHC revealed that fungi, gram-negative, and gram-positive bacteria primarily occupied separate dentinal tubules, with rare instances of colocalization. Similar findings were observed with multiplex immunofluorescence using anti-S. mutans and anti-C. albicans antibodies. Electron microscopy showed monomorphic bacterial and fungal biofilms within distinct dentin tubules. We demonstrate a previously unrecognized phenomenon in which fungi and bacteria occupy distinct spatial niches within carious dentin and seldom co-colonize. The potential significance of this phenomenon in caries progression warrants further exploration.
Topics: Humans; Dental Caries; Dentin; Male; Child; Female; Child, Preschool; Bacteria; Fungi; RNA, Ribosomal, 16S
PubMed: 38805482
DOI: 10.1371/journal.ppat.1011865 -
Acta Biomaterialia Jul 2017Limitations associated with wet-bonding led to the recent development of a selective demineralization strategy in which dentin was etched with a reduced concentration of...
UNLABELLED
Limitations associated with wet-bonding led to the recent development of a selective demineralization strategy in which dentin was etched with a reduced concentration of phosphoric acid to create exclusive extrafibrillar demineralization of the collagen matrix. However, the use of acidic conditioners removes calcium via diffusion of very small hydronium ions into the intrafibrillar collagen water compartments. This defeats the purpose of limiting the conditioner to the extrafibrillar space to create a collagen matrix containing only intrafibrillar minerals to prevent collapse of the collagen matrix. The present work examined the use of polymeric chelators (the sodium salt of polyacrylic acid) of different molecular weights to selectively demineralize extrafibrillar dentin. These polymeric chelators exhibit different affinities for calcium ions (isothermal titration calorimetry), penetrated intrafibrillar dentin collagen to different extents based on their molecular sizes (modified size-exclusion chromatography), and preserve the dynamic mechanical properties of mineralized dentin more favorably compared with completely demineralized phosphoric acid-etched dentin (nanoscopical dynamic mechanical analysis). Scanning and transmission electron microscopy provided evidence for retention of intrafibrillar minerals in dentin surfaces conditioned with polymeric chelators. Microtensile bond strengths to wet-bonded and dry-bonded dentin conditioned with these polymeric chelators showed that the use of sodium salts of polyacrylic acid for chelating dentin prior to bonding did not result in significant decline in resin-dentin bond strength. Taken together, the findings led to the conclusion that a chelate-and-rinse conditioning technique based on extrafibrillar collagen demineralization bridges the gap between wet and dry dentin bonding.
STATEMENT OF SIGNIFICANCE
The chelate-and-rinse dental adhesive bonding concept differentiates from previous research in that it is based on the size-exclusion characteristics of fibrillar collagen; molecules larger than 40kDa are prevented from accessing the intrafibrillar water compartments of the collagen fibrils. Using this chelate-and-rinse extrafibrillar calcium chelation concept, collagen fibrils with retained intrafibrillar minerals will not collapse upon air-drying. This enables adhesive infiltration into the mineral-depleted extrafibrillar spaces without relying on wet-bonding. By bridging the gap between wet and dry dentine bonding, the chelate-and-rinse concept introduces additional insight to the field by preventing exposure of endogenous proteases via preservation of the intrafibrillar minerals within a collagen matrix. If successfully validated, this should help prevent degradation of resin-dentine bonds by collagenolytic enzymes.
Topics: Collagen; Dentin; Humans; Molar; Tooth Demineralization
PubMed: 28499631
DOI: 10.1016/j.actbio.2017.05.017 -
Cryobiology Jun 2023This study focused on the biomechanical properties and microstructural changes in dentin of teeth in different age groups after cryopreserved for different durations....
This study focused on the biomechanical properties and microstructural changes in dentin of teeth in different age groups after cryopreserved for different durations. Ninety third molars from three age groups (youth group, middle-age group, and elderly group), were collected and randomly divided into three groups according to freezing time at -196 °C (7 days, 30 days, and 90 days). Control group was shored at ordinary temperature. After rewarming, the compressive strength and elastic modulus of the dentin were measured with an electronic universal tester. Scanning electron microscopy was used to evaluate the microstructure of dentin after cryopreservation. After cryopreservation, the compressive strength of the teeth in each experimental group was not significantly different from control group. With the increase of freezing time and age, dentin's elastic modulus showed a decreasing trend. There were statistically significances between the control group and freezing 90d group, freezing 7d and 90d group, youth and middle-aged group, youth and elderly group (P < 0.05). Both freezing time and age factors were significant for the elastic modulus of dentin(P<0.05). There was no interaction effect for age and freezing time. In transverse sections of scanning electron microscopy, the dentinal tubule became narrower, partially occluded, and more easily adhered to impurities in the long freezing time and elderly group. In longitudinal sections, with freezing time and age, the inner wall of the dentinal tubules became rough especially in the aged group cryopreserved for 90 days. No significant microcracks exited in any of the longitudinal sections of dentin.
Topics: Humans; Aged; Middle Aged; Adolescent; Infant; Cryopreservation; Dentin; Freezing; Microscopy, Electron, Scanning
PubMed: 37121387
DOI: 10.1016/j.cryobiol.2023.04.002