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Materials (Basel, Switzerland) Mar 2024Invisible orthodontic aligners are having a great impact on tooth movement in an aesthetic and effective way. Different techniques, models, and clinical aspects have...
Invisible orthodontic aligners are having a great impact on tooth movement in an aesthetic and effective way. Different techniques, models, and clinical aspects have been studied for their proper use. However, the aim of this research has been to determine the effect of the shaping process on mechanical properties and their bacterial behavior. For this study, 40 original polyurethane plates and 40 identical models, obtained by hot forming the original plates, were used. The static tensile mechanical properties were studied with a Zwick testing machine using testing speeds of 5 mm/min at a temperature of 37 °C. The original plate and the aligner have been studied with a creep test by subjecting the samples to a constant tension of 30 N, and determining the elongation using a long-distance, high-resolution microscope at different time periods between 1 and 720 h. Studies of water absorption has been realized with artificial saliva for 5 h. Bacterial cultures of and strains were grown on the original plates and on new and used models, to determine the proliferation of each bacterium through metabolic activity, colony-forming units, and LIVE/DEAD assays. The mechanical results showed an increase in the strength of the inserts with respect to the models obtained from 3.44 to 3.95 MPa in the elastic limit and a lower deformation capacity. It has been proven that the transition zone in the creep curves lasts longer in the original plate, producing the rapid increase in deformation at a shorter time (400 h) in the aligner. Therefore, the shaping process reduces the time of dental correction exerted by the aligner. The results of the bacterial culture assays show an increase in the number of bacterial colonies when the aligners have been used and when the polyurethane is conformed due to the internal energy of the model, with respect to the original polyurethane. It has been observed that between the original plate and the aligner there are no statistically significant differences in water absorption and therefore the forming process does not affect water absorption. A slight increase in water absorption can be observed, but after five hours of exposure, the increase is very small.
PubMed: 38541514
DOI: 10.3390/ma17061360 -
Biosensors Dec 2023Timely detection of highly infectious pathogens is essential for preventing and controlling public health risks. However, most traditional testing instruments require...
Timely detection of highly infectious pathogens is essential for preventing and controlling public health risks. However, most traditional testing instruments require multiple tedious steps and ultimately testing in hospitals and third-party laboratories. The sample transfer process significantly prolongs the time to obtain test results. To tackle this aspect, a portable fiber optic surface plasmon resonance (FO-SPR) device was developed for the real-time detection of infectious pathogens. The portable device innovatively integrated a compact FO-SPR sensing component, a signal acquisition and processing system, and an embedded power supply unit. A gold-plated fiber is used as the FO-SPR sensing probe. Compared with traditional SPR sensing systems, the device is smaller size, lighter weight, and higher convenience. To enhance the detection capacity of pathogens, a monolayer graphene was coated on the sensing region of the FO-SPR sensing probe. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was used to evaluate the performance of the portable device. The device can accurately detect the SARS-CoV-2 spike S1 protein in phosphate-buffered saline (PBS) and artificial saliva within just 20 min, and the device successfully detected cultured SARS-CoV-2 virus. Furthermore, the FO-SPR probe has long-term stability, remaining stable for up to 8 days. It could distinguish between the SARS-CoV-2 spike protein and the MERS-CoV spike protein. Hence, this FO-SPR device provides reliable, rapid, and portable access to test results. It provides a promising point-of-care testing (POCT) tool for on-site screening of infectious pathogens.
Topics: Humans; Surface Plasmon Resonance; Graphite; Fiber Optic Technology; Point-of-Care Testing; Biosensing Techniques
PubMed: 38131789
DOI: 10.3390/bios13121029 -
The Journal of Prosthetic Dentistry Apr 2024Although the intraoral scanning of edentulous ridges is feasible, clinical evidence that the resulting denture retention is equivalent to that achieved with conventional...
STATEMENT OF PROBLEM
Although the intraoral scanning of edentulous ridges is feasible, clinical evidence that the resulting denture retention is equivalent to that achieved with conventional impressions is lacking.
PURPOSE
The purpose of this clinical study was to determine the retention of complete denture bases fabricated from digital intraoral scans versus conventional impressions by using border molding and posterior palatal seal compression.
MATERIAL AND METHODS
Twenty volunteers with an edentulous maxilla were recruited. An intraoral scan of the maxilla and a conventionally border-molded impression with a custom tray were made. The conventional impression was poured; the definitive cast was scanned. Three-dimensionally (3D) printed (PB1) and milled bases (MB1) were fabricated based on the scan of the definitive cast. Based on the intraoral scan, a 3D printed (PB2) and a milled base (MB2) were fabricated. On each base, a platform with a hook consisting of a central notch orienting the force against the post dam (PD) and 2 lateral notches orienting the forces against the left (LT) and right (RT) tuberosities was set in the center of the outer surface of the base. A traction dynamometer was inserted in the hook and oriented into the corresponding notch by applying force until dislodgement. All bases were subsequently stored in artificial saliva for 2 weeks and scanned. Retention testing was repeated by using the same procedure. To evaluate trueness and to visualize the differences on a color map, the scan of the definitive cast and the intraoral scans were matched and compared in 3 dimensions. The Wilcoxon tests were used to compare the retention of the different bases (95% confidence interval, α=.05).
RESULTS
Nineteen participants with a mean ±standard deviation age of 64.1 ±14.7 years completed the 4 study sessions. The retention of printed bases (PD: 16.08 ±15.28 N; LT: 14.98 ±14.72 N; RT: 11.28 ±9.57 N) and milled bases (PD:14.52 ±17.07 N; RT: 11.99 ±12.10 N; LT: 13.55 ±15.53 N) fabricated from conventional impressions presented significantly higher retentive forces than those printed (PD: 6.21 ±4.72 N; RT:5.12 ±2.78 N; LT: 4.45 ±2.77 N) and milled (PD: 6.58 ±4.92 N; RT: 4.65 ±2.63 N; LT: 5.02 ±3.58 N) from the intraoral scans (P<.05). The differences were significant in all directions of dislodgement, as well as after storage in artificial saliva for 2 weeks. Comparison of the 3D distances between the intraoral scan and the definitive cast revealed a mean deviation of 0.45 ±0.11 mm.
CONCLUSIONS
Conventional impressions of the edentulous maxilla, including the clinical steps of border molding and posterior palatal seal compression, provide better retention than digital intraoral scans with both milled and 3D printed denture bases.
Topics: Humans; Middle Aged; Aged; Computer-Aided Design; Cross-Over Studies; Saliva, Artificial; Denture, Complete; Mouth, Edentulous; Denture Bases; Dental Impression Technique
PubMed: 36055812
DOI: 10.1016/j.prosdent.2022.07.004 -
Journal of Dental Research, Dental... 2023Orthodontic treatment is becoming more and more popular. However, using fixed orthodontic devices for treatment affects oral hygiene and raises the risk of corrosion,...
BACKGROUND
Orthodontic treatment is becoming more and more popular. However, using fixed orthodontic devices for treatment affects oral hygiene and raises the risk of corrosion, plaque-related illnesses, and dental discoloration-related issues. Air abrasive polishing has a superior effect over the conventional method in removing dental deposits. Using fixed orthodontic appliances affects oral hygiene and raises the risk of diseases caused by plaque, tooth discoloration, and corrosion, as well as corrosion by ions. This study evaluated the impact of air polishing on nickel ion release and corrosion from stainless steel, nickel-titanium, coated stainless steel, and coated nickel-titanium.
METHODS
A total of 288 (stainless steel, coated stainless-steel, nickel-titanium, and coated nickel-titanium rectangular archwires) of one brand were subjected to varying air abrasion polishing times (5, 10, and 20 seconds). Then, they were submerged in artificial saliva with a pH of 6.75 and incubated for 28 days at 37 °C. The release of nickel ions (Ni) was measured using an atomic absorption spectrophotometer at 7, 14, and 28 days to estimate the cumulative effect. The corrosion of the test-selected samples and surface alterations was evaluated using scanning electron microscopy (SEM).
RESULTS
Prolonged polishing significantly increased Ni release and corrosion. Archwires made of coated stainless steel exhibited the least amount of Ni release.
CONCLUSION
The air polishing process increased the Ni release at a subtoxic level and could be used on adult patients with long gaps between visits with a polishing period of 5 seconds.
PubMed: 38584995
DOI: 10.34172/joddd.2023.40536 -
Clinical and Experimental Dental... Aug 2023This in vitro work investigates the potential of ostrich eggshell as a substitute for extracted human teeth in preliminary screening studies on dental erosion....
OBJECTIVES
This in vitro work investigates the potential of ostrich eggshell as a substitute for extracted human teeth in preliminary screening studies on dental erosion. Additionally, it aims to demonstrate the potential of ostrich eggshell compared to human enamel in evaluating the efficacy of a preventive agent in protecting against dental erosion, using an artificial mouth model.
METHODS
The experiment utilized 96 erosion testing specimens from each substrate, human enamel, and ostrich eggshell. The specimens were subjected to six different experimental regimens of increasing erosive challenge, simulating the consumption of an acidic drink. The acidic drink was delivered at a consistent volume and duration range. Both artificially stimulated and unstimulated saliva flowed throughout the experimental regimens. Surface hardness was measured using a Through-Indenter Viewing hardness tester with a Vickers diamond, while surface profiling was done using a surface contacting profilometer with a diamond stylus. An automated chemistry analyzer system was used to detect calcium and phosphate ions.
RESULTS
The study found that ostrich eggshell specimens demonstrated predictable surface loss, hardness drop, and ion loss due to the acidic challenge. Meanwhile, enamel appeared to fall short in terms of surface hardness predictability. The transient hardness loss phase, which manifests as an overlooked decrease in surface hardness despite significant ion and structural loss, may explain this phenomenon.
CONCLUSIONS
The experiment showed that assessing surface loss is essential in addition to hardness testing, particularly as certain experimental conditions may produce a false perception of tissue recovery despite the actual surface loss. By analyzing the response of ostrich eggshell specimens to erosive challenges, researchers were able to identify an "overlooked" reduction in hardness in enamel specimens. The differences in the structure, chemical composition, and biological response to erosion in the presence of artificial saliva between enamel and ostrich eggshell could explain their distinct behaviors.
Topics: Animals; Humans; Struthioniformes; Tooth Erosion; Egg Shell; Dental Enamel; Saliva, Artificial
PubMed: 37106488
DOI: 10.1002/cre2.742 -
Journal of International Society of... 2023To evaluate the remineralization effect of a fluoride mouth rinse containing calcium glycerophosphate in fluoride mouth rinse based on the surface microhardness of...
AIM
To evaluate the remineralization effect of a fluoride mouth rinse containing calcium glycerophosphate in fluoride mouth rinse based on the surface microhardness of demineralized primary enamel.
MATERIALS AND METHODS
40 sound primary incisors were placed into self-curing acrylic resin and subjected to a demineralizing solution for 5 days, resulting in the formation of artificial caries. The teeth were categorized into four groups ( = 10): group I artificial saliva, group II sodium fluoride, group III sodium fluoride + sodium monofluorophosphate, and group IV sodium monofluorophosphate + calcium glycerophosphate. The specimens received a pH cycling procedure and were submerged twice in their assigned groups for 7 days. The baseline, after demineralization, and after remineralization surface microhardness values were determined. One-way analysis of variance (ANOVA) was used to analyze the mean surface microhardness between groups and one-way repeated measures ANOVA for the mean surface microhardness within each group and Bonferroni's for multiple comparisons at 95% confidence level. The percentage recovery surface microhardness was determined by calculating the average surface microhardness.
RESULTS
After demineralization, the mean surface microhardness in all groups significantly decreased. After remineralization, group I had the lowest surface microhardness values and the percentage recovery surface microhardness ( value < 0.001), and group IV had the highest surface microhardness values and the percentage recovery surface microhardness ( value < 0.001). No significant difference was found between groups II and III ( value = 0.365).
CONCLUSIONS
Fluoride mouth rinse containing calcium glycerophosphate has a remineralization effect on demineralized primary enamel.
PubMed: 38124723
DOI: 10.4103/jispcd.JISPCD_114_23 -
Nature Communications Jun 2024Virus infectivity is traditionally determined by endpoint titration in cell cultures, and requires complex processing steps and human annotation. Here we developed an...
Virus infectivity is traditionally determined by endpoint titration in cell cultures, and requires complex processing steps and human annotation. Here we developed an artificial intelligence (AI)-powered automated framework for ready detection of virus-induced cytopathic effect (DVICE). DVICE uses the convolutional neural network EfficientNet-B0 and transmitted light microscopy images of infected cell cultures, including coronavirus, influenza virus, rhinovirus, herpes simplex virus, vaccinia virus, and adenovirus. DVICE robustly measures virus-induced cytopathic effects (CPE), as shown by class activation mapping. Leave-one-out cross-validation in different cell types demonstrates high accuracy for different viruses, including SARS-CoV-2 in human saliva. Strikingly, DVICE exhibits virus class specificity, as shown with adenovirus, herpesvirus, rhinovirus, vaccinia virus, and SARS-CoV-2. In sum, DVICE provides unbiased infectivity scores of infectious agents causing CPE, and can be adapted to laboratory diagnostics, drug screening, serum neutralization or clinical samples.
Topics: Humans; Artificial Intelligence; Cytopathogenic Effect, Viral; SARS-CoV-2; Microscopy; COVID-19; Neural Networks, Computer; Animals; Vaccinia virus; Saliva; Chlorocebus aethiops; Vero Cells; Rhinovirus; Cell Line
PubMed: 38879641
DOI: 10.1038/s41467-024-49444-1 -
Biosensors Oct 2023A novel electrochemical DNA sensor was developed for the detection of the anthracycline drug, valrubicin, on the base of poly(Azure C) electropolymerized from the deep...
A novel electrochemical DNA sensor was developed for the detection of the anthracycline drug, valrubicin, on the base of poly(Azure C) electropolymerized from the deep eutectic solvent reline and covered with adsorbed DNA from calf thymus. Biosensor assembling was performed by multiple scanning of the potential in one drop (100 µL) of the dye dissolved in reline and placed on the surface of a screen-printed carbon electrode. Stabilization of the coating was achieved by its polarization in the phosphate buffer. The electrochemical characteristics of the electron transfer were determined and compared with a similar coating obtained from phosphate buffer. The use of deep eutectic solvent made it possible to increase the monomer concentration and avoid using organic solvents on the stage of electrode modification. After the contact of the DNA sensor with valrubicin, two signals related to the intrinsic redox activity of the coating and the drug redox conversion were found on voltammogram. Their synchronous changes with the analyte concentration increased the reliability of the detection. In the square-wave mode, the DNA sensor made it possible to determine from 3 µM to 1 mM (limit of detection, 1 µM) in optimal conditions. The DNA sensor was successfully tested in the voltammetric determination of valrubicin in spiked artificial urine, Ringer-Locke solution mimicking plasma electrolytes and biological samples (urine and saliva) with a recovery of 90-110%. After further testing on clinical samples, it can find application in the pharmacokinetics studies and screening of new drugs' interaction with DNA.
Topics: Deep Eutectic Solvents; Solvents; Reproducibility of Results; Electrodes; DNA; Phosphates; Electrochemical Techniques
PubMed: 37887124
DOI: 10.3390/bios13100931 -
Dental Materials : Official Publication... Dec 2023To examine whether lower dimethyl sulfoxide (DMSO) concentrations would affect long-term bond stability of simplified or multistep water-based adhesives to dry-etched... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To examine whether lower dimethyl sulfoxide (DMSO) concentrations would affect long-term bond stability of simplified or multistep water-based adhesives to dry-etched dentin.
METHODS
HPO-etched mid-coronal dentin surfaces from human molars were randomly blot- or air-dried for 30 s and pretreated or not with 5 or 50 % (v/v) ethanolic DMSO solutions. Untreated samples served as control. Samples were bonded with a two-step or a three-step etch-and-rinse adhesive. Restored crown segments (n = 5/group) were stored in distilled water for 24 h and sectioned for microtensile bond strength testing. Resin-dentin beams (0.8 mm) were tested under tension until fracture (0.5 mm/min) after 24 h and one year of storage in artificial saliva at 37 °C. Nanoleakage evaluation and hybrid layer characterization were performed by SEM. Bond strength data was examined by three-way ANOVA followed by the Tukey test (α = 0.05).
RESULTS
Dry bonding produced significantly lower bond strengths than conventional wet bonding for both water-based adhesive systems (p < 0.05). DMSO-dry bonding restored bond strengths and reduced nanoleakage levels, regardless of adhesive type or DMSO concentration (p < 0.05). Bond strengths of DMSO-dry bonded samples were not significantly affected by long-term ageing regardless of adhesive type or DMSO concentration (p < 0.05).
SIGNIFICANCE
Although bonding methacrylate-based resins to etched dentin is normally performed under wet conditions, hybridization of air-dried collagen can outperform conventional wet bonding by employing water-free DMSO solutions with concentrations as low as 5 %. Reduced moisture-related technique sensitivity, higher bonding performance and improved hybrid layer stability may contribute to extend the service life of resin-dentin bonding.
Topics: Humans; Dental Bonding; Dental Cements; Dentin; Dentin-Bonding Agents; Dimethyl Sulfoxide; Materials Testing; Resin Cements; Tensile Strength; Water
PubMed: 37838609
DOI: 10.1016/j.dental.2023.09.013 -
Contemporary Clinical Dentistry 2024This study aimed to assess the effect of a nano-hydroxyapatite (nano-HA) toothpaste on erosive enamel lesions of third molars induced by exposure to orange juice.
OBJECTIVES
This study aimed to assess the effect of a nano-hydroxyapatite (nano-HA) toothpaste on erosive enamel lesions of third molars induced by exposure to orange juice.
MATERIALS AND METHODS
In this , experimental study, the microhardness of 24 sound-extracted third molars was measured by a Vickers tester. The teeth were then randomly assigned to three groups ( = 8) of nano-HA toothpaste (Pharmed), 1.23% sodium fluoride gel, and artificial saliva. The teeth were exposed to orange juice for 5 min daily for 7 days and were then exposed to nano-HA toothpaste, fluoride gel, or artificial saliva (depending on their group allocation) for 10 min a day. The microhardness of the teeth was measured again after 7 days. Data were analyzed using paired -test, analysis of variance, and Bonferroni test (alpha = 0.05).
RESULTS
Within-group comparisons showed a significant reduction in microhardness of the teeth after the intervention in artificial saliva ( = 0.000), and fluoride gel ( = 0.002) groups. However, no significant reduction occurred in the microhardness of the nano-HA group, compared with the baseline ( = 0.132). Between-group comparisons revealed no significant difference in the microhardness of the three groups at baseline ( > 0.05). However, after the intervention, the microhardness of the nano-HA group was significantly higher than that of other groups ( < 0.05). However, the difference in secondary microhardness between fluoride gel and artificial saliva groups was not significant ( = 1.00).
CONCLUSION
Pharmed toothpaste containing nano-HA has optimal efficacy for remineralization of enamel erosive lesions induced by exposure to orange juice.
PubMed: 38707662
DOI: 10.4103/ccd.ccd_104_23