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Materials (Basel, Switzerland) Mar 2024Material-dependent parameters have an important impact on the efficiency of light polymerization. The present in vitro study aimed to investigate the influence of the...
BACKGROUND
Material-dependent parameters have an important impact on the efficiency of light polymerization. The present in vitro study aimed to investigate the influence of the increment thickness and shade of nano- and nanohybrid resin composites on the transmission of curing light.
METHODS
Three contemporary resin composites were evaluated: Tetric EvoCeram (TEC); Venus Diamond (VD); and Filtek Supreme XTE (FS XTE). Light transmission (LT) was recorded in accordance with the sample thickness (0.5 to 2.7 mm) and the shade. Polymerized samples were irradiated for 10 s each using the high-power LED curing light Celalux 2 (1900 mW/cm). LT was simultaneously recorded using the MARC Patient Simulator (MARC-PS).
RESULTS
LT was strongly influenced by the composite layer thickness. For 0.5 mm-thick samples, a mean power density of 735 mW/cm was recorded at the bottom side. For the 2.7 mm samples, a mean power density of 107 mW/cm was measured. Only LT was markedly reduced in the case of darker shades. From A1 to A4, LT decreased by 39.3% for FS XTE and 50.8% for TEC. Dentin shades of FS XTE and TEC (A2, A4) showed the lowest LT.
CONCLUSIONS
The thickness and shade of resin composite increments strongly influences the transmission of curing light. More precise information about these parameters should be included in the manufacture manual.
PubMed: 38612069
DOI: 10.3390/ma17071554 -
Brazilian Oral Research 2024Acidic pH can modify the properties of repair cements. In this study, volumetric change and solubility of the ready-to-use bioceramic repair cement Bio-C Repair (BCR,...
Acidic pH can modify the properties of repair cements. In this study, volumetric change and solubility of the ready-to-use bioceramic repair cement Bio-C Repair (BCR, Angelus, Londrina, PR, Brazil) were evaluated after immersion in phosphate-buffered saline (PBS) (pH 7.0) or butyric acid (pH 4.5). Solubility was determined by the difference in initial and final mass using polyethylene tubes measuring 4 mm high and 6.70 mm in internal diameter that were filled with BCR and immersed in 7.5 mL of PBS or butyric acid for 7 days. The volumetric change was established by using bovine dentin tubes measuring 4 mm long with an internal diameter of 1.5 mm. The dentin tubes were filled with BCR at 37°C for 24 hours. Scanning was performed with micro-computed tomography (micro-CT; SkyScan 1176, Bruker, Kontich, Belgium) with a voxel size of 8.74 µm. Then, the specimens were immersed in 1.5 mL of PBS or butyric acid at and 37 °C for 7 days. After this period, a new micro-CT scan was performed. Bio-C Repair showed greater mass loss after immersion in butyric acid when compared with immersion in PBS (p<0.05). Bio-C Repair showed volumetric loss after immersion in butyric acid and increase in volume after immersion in PBS (p<0.05). The acidic pH influenced the solubility and dimensional stability of the Bio-C Repair bioceramic cement, promoting a higher percentage of solubility and decrease in volumetric values.
Topics: Animals; Cattle; Solubility; Oxides; Calcium Compounds; X-Ray Microtomography; Butyric Acid; Materials Testing; Dental Cements; Glass Ionomer Cements; Hydrogen-Ion Concentration; Silicates; Root Canal Filling Materials
PubMed: 38597547
DOI: 10.1590/1807-3107bor-2024.vol38.0028 -
Frontiers in Microbiology 2024is a Gram-positive, facultative anaerobic bacterium, which causes dental caries after forming biofilms on the tooth surface while producing organic acids that...
is a Gram-positive, facultative anaerobic bacterium, which causes dental caries after forming biofilms on the tooth surface while producing organic acids that demineralize enamel and dentin. We observed that the polyunsaturated arachidonic acid (AA) (ω-6; 20:4) had an anti-bacterial activity against , which prompted us to investigate its mechanism of action. The minimum inhibitory concentration (MIC) of AA on was 25 μg/ml in the presence of 5% CO, while it was reduced to 6.25-12.5 μg/ml in the absence of CO supplementation. The anti-bacterial action was due to a combination of bactericidal and bacteriostatic effects. The minimum biofilm inhibitory concentration (MBIC) was the same as the MIC, suggesting that part of the anti-biofilm effect was due to the anti-bacterial activity. Gene expression studies showed decreased expression of biofilm-related genes, suggesting that AA also has a specific anti-biofilm effect. Flow cytometric analyses using potentiometric DiOC2(3) dye, fluorescent efflux pump substrates, and live/dead SYTO 9/propidium iodide staining showed that AA leads to immediate membrane hyperpolarization, altered membrane transport and efflux pump activities, and increased membrane permeability with subsequent membrane perforation. High-resolution scanning electron microscopy (HR-SEM) showed remnants of burst bacteria. Furthermore, flow cytometric analysis using the redox probe 2',7'-dichlorofluorescein diacetate (DCFHDA) showed that AA acts as an antioxidant in a dose-dependent manner. α-Tocopherol, an antioxidant that terminates the radical chain, counteracted the anti-bacterial activity of AA, suggesting that oxidation of AA in bacteria leads to the production of cytotoxic radicals that contribute to bacterial growth arrest and death. Importantly, AA was not toxic to normal Vero epithelial cells even at 100 μg/ml, and it did not cause hemolysis of erythrocytes. In conclusion, our study shows that AA is a potentially safe drug that can be used to reduce the bacterial burden of cariogenic .
PubMed: 38596377
DOI: 10.3389/fmicb.2024.1333274 -
Journal of Pharmacy & Bioallied Sciences Feb 2024Endodontic treatment involves the removal of infected dental pulp and subsequent disinfection of the root canal system. The effectiveness of drug delivery systems in...
BACKGROUND
Endodontic treatment involves the removal of infected dental pulp and subsequent disinfection of the root canal system. The effectiveness of drug delivery systems in root canal disinfection is critical for successful treatment outcomes. This study explores the potential of nanoparticles as a novel drug delivery system for endodontic treatment.
MATERIALS AND METHODS
Nanoparticles were synthesized using a biocompatible polymer and loaded with an antimicrobial agent. A total of 60 extracted human teeth were prepared to create standardized root canal infections. The teeth were randomly divided into three experimental groups: (1) conventional irrigation, (2) nanoparticle irrigation, and (3) control (no irrigation). The root canals in each group were irrigated with their respective solutions for 5 minutes. After treatment, microbial samples were collected from the root canals and cultured for colony-forming unit (CFU) analysis. The depth of penetration of nanoparticles into dentinal tubules was assessed using scanning electron microscopy (SEM).
RESULTS
The conventional irrigation group showed a reduction in microbial load from an average of 7.8 × 10^5 CFU/mL (SD ± 1.2 × 10^5) to 3.4 × 10^4 CFU/mL (SD ± 7.9 × 10^3) ( < 0.001). In contrast, the nanoparticle irrigation group exhibited a more significant reduction, with a decrease in CFU to 1.2 × 10^3 CFU/mL (SD ± 4.2 × 10^2) ( < 0.001). SEM analysis revealed deep penetration of nanoparticles into dentinal tubules, reaching an average depth of 150 μm.
CONCLUSION
Nanoparticles loaded with antimicrobial agents demonstrated superior efficacy in reducing microbial load within root canals compared to conventional irrigation. Their ability to penetrate dentinal tubules suggests their potential as an innovative drug delivery system for endodontic treatment. Further research and clinical trials are warranted to validate these promising results and assess the safety and efficacy of nanoparticles in clinical practice.
PubMed: 38595519
DOI: 10.4103/jpbs.jpbs_1093_23 -
BMC Oral Health Apr 2024To evaluate the physical properties of bioactive glass-modified universal multimode adhesive and its micro-tensile bond strength (µTBS) to artificially induced...
BACKGROUND
To evaluate the physical properties of bioactive glass-modified universal multimode adhesive and its micro-tensile bond strength (µTBS) to artificially induced caries-affected dentin.
METHODS
All bond universal adhesive was used in the study. Specimens were divided into 2 main groups: control unmodified adhesive and 5 wt% BAG modified adhesive. The degree of conversion, pH, bioactivity, and viscosity of the adhesives were tested with n = 5 for each test. Micro-tensile bond strength evaluation was done in etch & rinse (ER) and selective-etch (SE) modes, where 24 human molar teeth were used (n = 3), 12 teeth for immediate bond strength, and the other 12 were tested after 6 months of storage in simulated body fluid (SBF).
RESULTS
No significant difference was found between the control and the 5wt% BAG groups regarding the degree of conversion (61.01 ± 0.43 and 60.44 ± 0.61 respectively) and the viscosity (109.77 ± 22.3 and 124.3 ± 9.92 respectively). The control group revealed significantly lower pH values than the 5wt% BAG group (3.16 ± 0.5 and 4.26 ± 0.09 respectively). Immediate bond strength results revealed that the 5wt% BAG in the ER mode had the highest bond strength followed by the control group in the ER mode (44.16 ± 7.53 and 44.00 ± 7.96 respectively). SE groups showed that the immediate strength of the 5wt% BAG group was higher than the control group (42.09 ± 6.02 and 39.29 ± 6.64 respectively). After 6 months of storage, bond strength results revealed a decrease in bond strength values for the control groups but not for the 5wt% BAG in both application modes.
CONCLUSIONS
The incorporation of BAG (5wt%) improved the universal adhesive micro-tensile bond strength and bond durability for both adhesive application modes without affecting its degree of conversion or viscosity.
Topics: Humans; Dental Cements; Dentin-Bonding Agents; Resin Cements; Dental Bonding; Dental Caries Susceptibility; Materials Testing; Dental Caries; Tensile Strength; Dentin
PubMed: 38580948
DOI: 10.1186/s12903-024-04175-z -
Journal of Dentistry Jun 2024Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the... (Review)
Review
OBJECTIVE
Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the restorations. This review aims to summarise the current knowledge on the influence of a variety of clinical contaminants on the bond strength at various adhesive interfaces during adhesive restorative procedures and identify gaps in the literature for future research.
DATA AND SOURCES
An electronic database search was performed in PubMed and EMBASE to identify articles that investigated the influence of contaminants on direct restorative bonding procedures. A data-charting form was developed by two researchers to capture the key characteristics of each eligible study.
STUDY SELECTION
The initial search yielded 1,428 articles. Fifty-seven articles published between 1 Jan 2007 and 25 Oct 2023 were included in the final review. Thirty-three of the articles examined the influence of saliva contamination, twelve articles examined the influence of blood contamination, and twenty-five articles examined the influence of other contaminants.
CONCLUSION
Saliva contamination exerted less influence on the decrease in bond strength when self-etch systems were used, compared to when etch-and-rinse systems were used. Blood contamination adversely affected the bond strength at the interface between resin composite and dentine, and resin composite and resin-modified glass ionomer cement. Treating contaminated surfaces with water spray for 10-30 s followed by air drying could be effective in recovering bond strength following saliva and blood contamination.
CLINICAL SIGNIFICANCE
This scoping review provides a valuable overview of the range of potential clinical contaminants that can influence the bond strength between different interfaces in direct adhesive restorative procedures. Additionally, it identifies potential decontamination protocols that can be followed to restore and enhance bond strength.
Topics: Humans; Dental Bonding; Composite Resins; Dental Restoration, Permanent; Saliva; Glass Ionomer Cements; Dentin-Bonding Agents; Materials Testing; Dentin; Dental Cements; Dental Stress Analysis; Surface Properties; Resin Cements
PubMed: 38574846
DOI: 10.1016/j.jdent.2024.104985 -
Scientific Reports Apr 2024Hypomyelinating leukodystrophy (HLD) is a rare genetic heterogeneous disease that can affect myelin development in the central nervous system. This study aims to analyze...
Hypomyelinating leukodystrophy (HLD) is a rare genetic heterogeneous disease that can affect myelin development in the central nervous system. This study aims to analyze the clinical phenotype and genetic function of a family with HLD-7 caused by POLR3A mutation. The proband (IV6) in this family mainly showed progressive cognitive decline, dentin dysplasia, and hypogonadotropic hypogonadism. Her three old brothers (IV1, IV2, and IV4) also had different degrees of ataxia, dystonia, or dysarthria besides the aforementioned manifestations. Their brain magnetic resonance imaging showed bilateral periventricular white matter atrophy, brain atrophy, and corpus callosum atrophy and thinning. The proband and her two living brothers (IV2 and IV4) were detected to carry a homozygous mutation of the POLR3A (NM_007055.4) gene c. 2300G > T (p.Cys767Phe), and her consanguineous married parents (III1 and III2) were p.Cys767Phe heterozygous carriers. In the constructed POLR3A wild-type and p.Cys767Phe mutant cells, it was seen that overexpression of wild-type POLR3A protein significantly enhanced Pol III transcription of 5S rRNA and tRNA Leu-CAA. However, although the mutant POLR3A protein overexpression was increased compared to the wild-type protein overexpression, it did not show the expected further enhancement of Pol III function. On the contrary, Pol III transcription function was frustrated (POLR3A, BC200, and tRNA Leu-CAA expression decreased), and MBP and 18S rRNA expressions were decreased. This study indicates that the POLR3A p.Cys767Phe variant caused increased expression of mutated POLR3A protein and abnormal expression of Pol III transcripts, and the mutant POLR3A protein function was abnormal.
Topics: Male; Female; Humans; Hereditary Central Nervous System Demyelinating Diseases; Mutation; Phenotype; Atrophy; RNA, Transfer; RNA Polymerase III
PubMed: 38561452
DOI: 10.1038/s41598-024-58452-6 -
Journal of International Society of... 2024To determine the effect of an herbal toothpaste containing Little Ironweed and Java Tea, on reducing dentine permeability .
AIM
To determine the effect of an herbal toothpaste containing Little Ironweed and Java Tea, on reducing dentine permeability .
MATERIALS AND METHODS
Dentine discs from human mandibular third molars were divided into three groups and brushed with herbal toothpaste, nonherbal toothpaste, or deionized water. Each group was immersed in artificial saliva (AS) or 6% citric acid. The permeability of each dentine disc was evaluated before and after saliva or acid challenge using a fluid filtration system. The morphology of dentine discs after treatment was observed using scanning electron microscopy (SEM). The mean permeabilities were statistically analyzed using analysis of variance and Tukey's test.
RESULTS
The nonherbal and herbal toothpaste groups demonstrated reduced dentine permeability. AS immersion decreased dentine permeability in both toothpaste groups with values lower than the control group. Dentine permeability values increased after acid immersion in the toothpaste groups and were similar to each other. SEM revealed small granular crystal-like and round particles on the dentine surface and opening of dentinal tubules of both toothpaste groups. More dentinal tubules were opened after brushing with deionized water.
CONCLUSIONS
The reduction of dentine permeability caused by the herbal toothpaste was similar to that of the nonherbal toothpaste after brushing and the simulated oral conditions. Both herbal plants have the possibility to alleviate clinical hypersensitivity by reducing dentine permeability. Little Ironweed and Java Tea in the toothpaste composition is a potential choice for treating hypersensitive dentine.
PubMed: 38559639
DOI: 10.4103/jispcd.jispcd_67_23 -
Materials (Basel, Switzerland) Mar 2024The aim of this study is to analyze the effects of different endodontic irrigants and adhesive systems on the resin bond strength of fiber post cementation. In total,...
The aim of this study is to analyze the effects of different endodontic irrigants and adhesive systems on the resin bond strength of fiber post cementation. In total, 144 single-rooted, unrestored human teeth were endodontically treated and randomly divided into 12 groups according to four endodontic irrigants (distilled water as control; EDTA 17%; NaOCl 5%; chlorhexidine digluconate 2%) and three different adhesive/resin cement systems (etch-and-rinse: orthophosphoric acid, Parabond A+B/Paracore; self-etch: ParaBond Non-Rinse Conditioner, Parabond A+B/Paracore; Universal: Clearfil Universal Bond/Clearfil DC Core Plus). Forty-eight hours after post cementation, ten teeth from each group were cross-sectioned into three discs (cervical, middle and apical regions). Thirty specimens of each group ( = 30) were submitted to a push-out test at a crosshead speed of 1 mm/min. The remaining two teeth of each group were sectioned in the same manner, and the resin-dentin interface was evaluated using scanning electron microscopy (SEM). The results were statistically analyzed with the ANOVA test and Tukey's test ( < 0,01). The adhesive protocols and post space region showed no significant effect on bond strength ( > 0.01). The combination of NaOCl 5% and ClearfilTM Universal Bond reduced the adhesive strength ( < 0.01). The NaOCl 5%, in relation to other irrigants, significantly decreased the push-out bond strength.
PubMed: 38541586
DOI: 10.3390/ma17061432 -
Brazilian Dental Journal 2024The aim was to evaluate the effect of stress distribution on vertical, horizontal, and oblique forces on the tooth model after reattaching the fragments of the maxillary...
The aim was to evaluate the effect of stress distribution on vertical, horizontal, and oblique forces on the tooth model after reattaching the fragments of the maxillary incisor with vertical root fracture (VRF) using different materials, by 3D finite element analysis (FEA). Tooth with a root canal, spongious, and cortical bone models were designed. VRF was modeled on a tooth with 4 different re-attachment models: Group 1: dual-cure cement (DC)+fiber reinforced composite (FRC), Group 2: DC+polyethylene fiber, Group 3: DC+glass fiber, and Group 4:DC. 100 N force was applied in 3 different directions. Maximum principal stresses (σmax) of dentin, and re-attachment materials were evaluated on colored images. The highest σmax values were on the repair materials under vertical forces for Groups 1 and 4, respectively; Groups 2 and 3 showed similarity. The highest σmax values in repair materials under horizontal and oblique forces were observed in Group 3 however the lowest σmax values in repair materials under oblique and horizontal forces were observed in Group 1. The stress values on repair materials gradually increased respectively starting from horizontal to vertical. As the elasticity modulus of the repair materials increased, the stress values on root dentin increased. Through all force directions, except vertical forces, lower stress values were observed with FRC. The fracture resistance was bigger when using solely FRC or dual-cure resin cement in comparison to fiber-supported designs. Adding polyethylene fiber to re-restorations decreased stress values compared to glass fiber addition. Therefore, when adding fibers, polyethylene fiber will be advantageous.
Topics: Dental Materials; Composite Resins; Dental Pulp Cavity; Finite Element Analysis; Post and Core Technique; Polyethylene; Stress, Mechanical; Materials Testing; Dental Stress Analysis; Glass
PubMed: 38537024
DOI: 10.1590/0103-6440202405833