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Indian Journal of Dental Research :... Jan 2024Wet oral environment may have deleterious effects on performance of the composites due to influences of water sorption and solubility. The study evaluated the hydrolytic...
INTRODUCTION
Wet oral environment may have deleterious effects on performance of the composites due to influences of water sorption and solubility. The study evaluated the hydrolytic degradation caused because of water sorption and solubility of silorane and methacrylate-based dental composites.
METHODS
Ten disc samples (2 mm × 10 mm) were prepared. Samples were analyzed for water solubility and sorption according to ISO 4049:2000 regulations and tested for mass gain or loss following immersion in water or in artificial saliva at 1 day, 15 days, and 30 days period. Student's 't' test, repeated measures analysis of variance (ANOVA), and Tukey's post-hoc tests determined statistical significance of the experimental results with global significance set at P = 0.05.
RESULTS
Considerable sorption and solubility was observed with time in both materials on immersion. Silorane composites showed lower water sorption and solubility than methacrylate-based composite (MBC). Artificial saliva demonstrated higher sorption and solubility compared to distilled water.
CONCLUSION
Silorane composites display enhanced hydrolytic stability even after a month of immersion in contrast to conventional methacrylate-based composites (MBCs), making it a better alternative to MBC resins clinically.
Topics: Solubility; Methacrylates; Composite Resins; Water; Silorane Resins; Saliva, Artificial; Materials Testing; Hydrolysis; Dental Materials
PubMed: 38934754
DOI: 10.4103/ijdr.ijdr_195_23 -
Sensors (Basel, Switzerland) Jun 2024Salivary pH is one of the crucial biomarkers used for non-invasive diagnosis of intraoral diseases, as well as general health conditions. However, standard pH sensors...
Salivary pH is one of the crucial biomarkers used for non-invasive diagnosis of intraoral diseases, as well as general health conditions. However, standard pH sensors are usually too bulky, expensive, and impractical for routine use outside laboratory settings. Herein, a miniature hydrogel sensor, which enables quick and simple colorimetric detection of pH level, is shown. The sensor structure was manufactured from non-toxic hydrogel ink and patterned in the form of a matrix with 5 mm × 5 mm × 1 mm individual sensing pads using a 3D printing technique (bioplotting). The authors' ink composition, which contains sodium alginate, polyvinylpyrrolidone, and bromothymol blue indicator, enables repeatable and stable color response to different pH levels. The developed analysis software with an easy-to-use graphical user interface extracts the R(ed), G(reen), and B(lue) components of the color image of the hydrogel pads, and evaluates the pH value in a second. A calibration curve used for the analysis was obtained in a pH range of 3.5 to 9.0 using a laboratory pH meter as a reference. Validation of the sensor was performed on samples of artificial saliva for medical use and its mixtures with beverages of different pH values (lemon juice, coffee, black and green tea, bottled and tap water), and correct responses to acidic and alkaline solutions were observed. The matrix of square sensing pads used in this study provided multiple parallel responses for parametric tests, but the applied 3D printing method and ink composition enable easy adjustment of the shape of the sensing layer to other desired patterns and sizes. Additional mechanical tests of the hydrogel layers confirmed the relatively high quality and durability of the sensor structure. The solution presented here, comprising 3D printed hydrogel sensor pads, simple colorimetric detection, and graphical software for signal processing, opens the way to development of miniature and biocompatible diagnostic devices in the form of flexible, wearable, or intraoral sensors for prospective application in personalized medicine and point-of-care diagnosis.
Topics: Colorimetry; Printing, Three-Dimensional; Hydrogen-Ion Concentration; Saliva; Hydrogels; Humans; Biosensing Techniques
PubMed: 38931525
DOI: 10.3390/s24123740 -
Journal of Applied Oral Science :... 2024This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models. (Comparative Study)
Comparative Study
OBJECTIVE
This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models.
METHODOLOGY
In total, 45 human enamel specimens were sterilized and allocated into three groups based on the biofilm model: Streptococcus sobrinus and Lactobacillus casei (Ss+Lc), Streptococcus sobrinus (Ss), or Streptococcus mutans (Sm). Specimens were incubated in filter-sterilized human saliva to form the acquired pellicle and then subjected to the biofilm challenge consisting of three days of incubation with bacteria (for demineralization) and one day of remineralization, which was performed once for Ss+Lc (four days total), four times for Ss (16 days total), and three times for Sm (12 days total). After WSL creation, the lesion fluorescence, depth, and chemical composition were assessed using Quantitative Light-induced Fluorescence (QLF), Polarized Light Microscopy (PLM), and Raman Spectroscopy, respectively. Statistical analysis consisted of two-way ANOVA followed by Tukey's post hoc test (α=0.05). WSL created using the Ss+Lc protocol presented statistically significant higher fluorescence loss (ΔF) and integrated fluorescence (ΔQ) in comparison to the other two protocols (p<0.001).
RESULTS
In addition, Ss+Lc resulted in significantly deeper WSL (137.5 µm), followed by Ss (84.1 µm) and Sm (54.9 µm) (p<0.001). While high mineral content was observed in sound enamel surrounding the WSL, lesions created with the Ss+Lc protocol showed the highest demineralization level and changes in the mineral content among the three protocols.
CONCLUSION
The biofilm model using S. sobrinus and L. casei for four days was the most appropriate and simplified protocol for developing artificial active WSL with lower fluorescence, higher demineralization, and greater depth.
Topics: Biofilms; Humans; Streptococcus mutans; Dental Caries; Dental Enamel; Lacticaseibacillus casei; Time Factors; Reproducibility of Results; Streptococcus sobrinus; Spectrum Analysis, Raman; Analysis of Variance; Microscopy, Polarization; Statistics, Nonparametric; Tooth Remineralization; Reference Values; Saliva; Tooth Demineralization; Fluorescence
PubMed: 38922241
DOI: 10.1590/1678-7757-2023-0458 -
Acta Odontologica Latinoamericana : AOL Apr 2024Glass ceramics are widely used to manufacture esthetic veneers, inlays, onlays, and crowns. Although the clinical survival rates ofglass-ceramic restorations...
UNLABELLED
Glass ceramics are widely used to manufacture esthetic veneers, inlays, onlays, and crowns. Although the clinical survival rates ofglass-ceramic restorations arefavorable,fractures or chips are common. Certain cases can be repaired with direct composite.
AIM
The aim of this study was to investigate the interaction effect of different designs and surface treatments on the load-to-failure of lithium disilicate glass-ceramic repaired with nanofilled composite.
MATERIALS AND METHOD
Lithium-disilicate glass-ceramic slabs (IPS e.max Press, Ivoclar Vivadent) with three different designs of the top surface (flat, single plateau, or doubleplateau) (n=U) received 'no treatment', '5% HF etching', or "AI2O3 sandblasting". HF-etched and sandblasted slabs also received silane and universal one-step adhesive application. All slabs were incrementally repaired with nanofilled composite (Filtek Z350, 3M ESPE) up to6 mm above the highest ceramic top plateau. Specimens were stored in artificial saliva at 37 °C for 21 days and then subjected to 1,000 thermocycles between 5 and 55 °C. The interface composite-ceramic of each specimen was tensile tested until failure in a universal testing machine and the mode of failure was determined under a stereomicroscope. The ceramic surface morphology of one representative tested specimen from each subgroup (design/surface treatment) was observed through scanning electron microscopy (SEM).
RESULTS
Regardless of ceramic design, the absence of surface treatment resulted in significantly lower load-to-failure values. No significant differences in load-to-failure values were observed between HF-etched and sandblasted specimens for the flat design; however, HF etching resulted in significantly higher load-to-failure values than sandblasting for both single plateau and double plateau designs. The majority (60%) of HF-etched specimens with single plateau or double plateau presented mixed failures. SEM photomicrographs showed that HF-etched specimens had smoother surfaces than sandblasted specimens.
CONCLUSION
The surface treatment of a defective lithium disilicate glass-ceramic restoration has more influence than its macroscopic design on the retention of the composite repair. HF etching seems to provide higher bond strength to the composite repair.
Topics: Ceramics; Surface Properties; Dental Porcelain; Materials Testing; Dental Restoration Failure; Composite Resins; Dental Stress Analysis; Dental Prosthesis Design
PubMed: 38920130
DOI: 10.54589/aol.37/1/88 -
Acta Odontologica Latinoamericana : AOL Apr 2024Coloured compounds (anthocyanins) in açaí can stain resin-modified glass-ionomer cement (RMGIC) due to its low staining resistance.
UNLABELLED
Coloured compounds (anthocyanins) in açaí can stain resin-modified glass-ionomer cement (RMGIC) due to its low staining resistance.
AIM
The aim of this study was to assess whether açaí compromises the surface colour and roughness of RMGIC in vitro.
MATERIALS AND METHOD
Disc-shaped specimens (2 mm thick, 8 mm in diameter) of Vitremer™ (3M ESPE, St Paul, MN, USA) were prepared according to the manufacturer 's instructions. The mixture was inserted into a silicone mouldplaced between two mylar strips, and light cured. Specimens were randomly divided into three groups (n=25) according to the solutions to be used for chemical degradation: artificial saliva (control), açaí sorbet and açaí juice. A spectrophotometer CM-2600d/2500d (Konica Minolta, Tokyo, Japan) was used to analyse the colour (CIELa*b* scale). Surface roughness (Ra, mm) was measuredusing theprofilometer Surfcorder SE 1700 (Kosaka Corp, Tokyo, Japan). The specimens were subjected to three daily soaks (6 ml, 15 minutes) for 14 days at 37°C. They were washed in distilled water and placed in fresh saliva (30 minutes in the interval). After the third soak in a day, they were stored in fresh saliva overnight. Outcomes were analysed at baseline (L*, a*, b*, Ra) and after degradation (L'*, a'*, b'*, Ra').
RESULTS
The pH values of saliva, sorbet, and juice were 7.0, 3.8, and 4.9, respectively. ΔE* values were 6.6 for saliva, 6.9 for sorbet and 7.8 for juice. There was a significant ΔE* difference between saliva (p=0.005) and juice (p=0.002), and between juice and sorbet (p=0.019), but none between saliva and sorbet (p=0.401). There was no significant Δb* difference between the solutions. No difference between juice and sorbet was observed for Δa*, but they were significantly different from saliva (p<0.001). Brightness (L*) changed significantly. Juice showed the highest ΔE* (7.8) and ΔL* (7.7). No significant change was observed for roughness and there was no difference between the solutions for ARa.
CONCLUSIONS
Açaí and saliva led to unacceptable staining, but no significant roughness changes in the resin-modified glass-ionomer cement.
Topics: Glass Ionomer Cements; Color; Materials Testing; Surface Properties; Carbonated Beverages
PubMed: 38920125
DOI: 10.54589/aol.37/1/40 -
International Journal of Biomaterials 2024Three-dimensional (3D) printing is becoming more prevalent in the dental sector due to its potential to save time for dental practitioners, streamline fabrication...
Three-dimensional (3D) printing is becoming more prevalent in the dental sector due to its potential to save time for dental practitioners, streamline fabrication processes, enhance precision and consistency in fabricating prosthetic models, and offer cost-effective solutions. However, the effect of aging in artificial saliva of this type of material has not been explored. To assess the physical and mechanical properties of the two types of 3D-printed materials before and after being subjected to artificial saliva, a total of 219 acrylic resin specimens were produced. These specimens were made with two types of 3D-printed materials, namely, NextDent (ND) and Formlabs (FLs), and a Schottlander heat-cured (HC) resin material that was used as a control. Water sorption and solubility specimens ( = 5) were tested after three months of storage in artificial saliva. Moreover, the Vickers hardness, Martens hardness, flexural strength/modulus, and impact strength were evaluated both under dry conditions and after three months of storage in artificial saliva. The degree of conversion (DC), elemental analysis, and filler content were also investigated. The ANOVA showed that 3D-printed resins had significantly greater sorption than the control group ( < 0.05). However, the flexural strength values of the 3D-printed materials were significantly greater ( < 0.05) than those of the heat-cured material. The DC of the 3D-printed resins was lower than that of the control group, but the difference was not significant ( > 0.05). The 3D-printed materials contained significantly more filler than the control ( < 0.05). Moreover, the artificial saliva had a significant effect on the Vickers hardness for all tested groups and on the Martens hardness for the control group only ( < 0.05). Compared with conventional heat-cured materials, 3D-printed denture base materials demonstrated relatively poorer performance in terms of sorption, solubility, and DC but exhibited either comparable or superior mechanical properties. The aging process also influenced the Vickers and Martens' hardness. The strength of the 3D-printed materials was in compliance with ISO recommendations, and the materials could be used alongside conventional heat-cured materials.
PubMed: 38919543
DOI: 10.1155/2024/8060363 -
Clinical, Cosmetic and Investigational... 2024This in vitro study investigated the effects of dietary solvents on the microhardness and color stability of CAD/CAM provisional restorations compared to conventional...
PURPOSE
This in vitro study investigated the effects of dietary solvents on the microhardness and color stability of CAD/CAM provisional restorations compared to conventional materials.
METHODS
Disc-shaped specimens (n=200) were fabricated from self-cured acrylic resin, two 3D-printing resins (FormLabs, NextDent), and a milled material (TelioCAD). Randomization assigned specimens (n=10/group) to immersion solutions: artificial saliva, citric acid, heptane, coffee, and tea. Microhardness and color stability were evaluated. One-way and three-way ANOVA with Tukey's post hoc test analyzed the data.
RESULTS
Dietary solvents significantly reduced the surface microhardness of all tested materials (p<0.05). Unpolished surfaces exhibited greater color changes compared to polished ones (p<0.05) across all materials. Coffee and tea induced the most substantial reductions in hardness and the most significant color alterations (p<0.05), whereas saliva and citric acid had minimal effects.
CONCLUSION
Milled provisional restorations exhibited superior hardness and color stability. Dietary solvents significantly affected material properties over time, highlighting the importance of material selection for clinical applications.
PubMed: 38915917
DOI: 10.2147/CCIDE.S462107 -
Cureus Jun 2024The purpose of this in vitro study was to evaluate the potential remineralization of enamel and dentine erosion lesions after the application of five different...
OBJECTIVE
The purpose of this in vitro study was to evaluate the potential remineralization of enamel and dentine erosion lesions after the application of five different toothpastes.
METHODOLOGY
A total of 104 enamel and dentine samples were prepared from maxillary third molars. Each group was divided according to the toothpaste application mode (topical = 56; brushing = 48) and the toothpaste used seven topical groups and six brushing groups (n = 8). The groups included negative control (NC), positive control (PC), Sensodyne Pronamel (SP), Regenerate (R), Regenerate with boosting serum (R+), Colgate Duraphat 5000 (CD), and tooth mousse (TM).
RESULTS
The statistical analysis showed significant surface microhardness (SMH) change. All enamel groups showed a significant decrease in SMH compared to NC for both application modes. However, no significance was recorded between test groups. Similar results were observed between dentine groups and their relevant controls for both application modes, except brushed R and R+ groups, which were insignificant to their NC. For topical groups, TM showed a significant increase in SMH. While R and R+ showed lower loss than SP and CD.
CONCLUSIONS
All tested agents offered a degree of remineralization in both enamel and dentine with no significant difference between agents in enamel groups while R, R+, and TM offered better results in dentine groups.
CLINICAL SIGNIFICANCE
For dentine groups, similar findings were observed with superior tooth surface protection with the application of TM over other agents. Tooth surface remineralization was achieved when agents were either applied topically or brushed over the surface.
PubMed: 38912082
DOI: 10.7759/cureus.62921 -
Cureus May 2024In orthodontics, shear bond strength plays an important role because it provides a good bond between the brackets and tooth surface; it avoids fracture of the tooth...
INTRODUCTION
In orthodontics, shear bond strength plays an important role because it provides a good bond between the brackets and tooth surface; it avoids fracture of the tooth surface and prevents debonding of brackets from the tooth surface. All of these allow sufficient treatment time. Many factors, including the adhesive, its thickness, its strength, the bonding procedure, the clinician's ability, the base design, the geometry of the bracket, the material, and the kind of bracket all contribute to the shear bond strength. Brackets joined using conventional adhesive and adhesive pre-coated (APC) flash-free glue were the subjects of this comparison and evaluation research, which aimed to measure shear bond strength, enamel microfracture, and adhesive residual index.
METHOD
60 recently removed premolars from humans were used in this investigation. Before mounting on the acrylic block, the teeth were meticulously cleaned and preserved in artificial saliva. Two groups were formed from the collected premolars the control group and the experimental group. For the control group, we used American Orthodontics (AO) Master/Mini Master series brackets glued with resin composite kits. To make sure the adhesive was uniformly thick, we flashed extra adhesive around the brackets. In the meantime, samples were bonded using 3M Unitek APC flash-free technology in the experimental group.
RESULTS
The research indicated that there was a statistically significant difference between the two groups to the adhesive remnant index (ARI) and mean shear bond strength. The shear bond strength of the experimental group averaged 10.96 megapascals (MPa), whereas the control group's was 5.70 MPa. The control group's ARI score was 2.97, whereas the experimental group's score was 2.4. There was no statistically significant change seen in enamel microfracture.
CONCLUSION
A more robust shear bond may be possible using APC flash-free brackets. Compared to conventional bonding techniques and brackets, APC flash-free brackets have a lower adhesive residual index. The APC flash-free bracket technology also causes more enamel microfracture than conventional bonding and bracketing methods.
PubMed: 38910749
DOI: 10.7759/cureus.60928 -
Dental Materials : Official Publication... Jun 2024Baghdadite (CaZrSiO) cements of various composition have been investigated in this study regarding an application as endodontic filling materials.
OBJECTIVES
Baghdadite (CaZrSiO) cements of various composition have been investigated in this study regarding an application as endodontic filling materials.
METHODS
Cements were either obtained by mixing mechanically activated baghdadite powder with water (maBag) or by subsequently substituting the ß-tricalcium phosphate (ß-TCP) component in a brushite forming calcium phosphate cement. The cements were analyzed for their mechanical performance, injectability, radiopacity, phase composition and antimicrobial properties.
RESULTS
The cements demonstrated sufficient mechanical performance with a compressive strength of ∼1 MPa (maBag) and 2.3 - 17.4 MPa (substituted calcium phosphate cement), good injectability > 80 % depending on the powder to liquid ratio and an intrinsic radiopacity of 1.13 - 2.05 mm aluminum equivalent. Immersion in artificial saliva proved their bioactivity by the formation of calcium phosphate and calcium silicate precipitates on the cement surface. The bacterial activity of Staphylococcus aureus cultured on the surface of the cements was found to be similar compared to clinical standard ProRoot MTA cement or even reduced by a factor of 3 for Streptococcus mutans.
SIGNIFICANCE
In combination with their antibacterial properties, baghdadite cements are thought to have the potential to fulfil the clinical requirements for endodontic filling materials.
PubMed: 38890091
DOI: 10.1016/j.dental.2024.05.026