Forrestsanford0179
To evaluate the effect of bacterial exposure on the marginal integrity of dentin-resin interfaces for composites with and without bioactive glass (BAG).
Cavity preparations of 5 mm width and 1.5 mm depth were machined into dentin disks by means of a computer controlled milling system. After applying the bonding agent, cavity preparations (n=3-5) were restored by incremental technique with experimental resin composites (5050 BisGMA/TEGDMA 72wt% filler) with different filler compositions control - 67 wt% silanated strontium glass and 5wt% aerosol-silica filler and BAG - 57 wt% silanated strontium glass and 15 wt% BAG-65 wt% silica. Samples were then stored in sterile Todd-Hewitt media or co-incubated with Streptococcus mutans (UA 159), at 37°C, 5% CO2 for 1-2 weeks. For samples co-incubated with a living biofilm, a luciferase assay was performed in order to assess its viability. Surfaces were impressed before and after each storage condition and replicas examined in a scanning electron microscope. Using imagher gap percentage in the margins, confirming the negative effect of cariogenic bacteria on margin degradation. The parameters defined for such synergy can help to understand the multi-factorial aspect of marginal discontinuity and therefore, predict the behavior of composite restorations subjected to the challenging oral environment.
To evaluate the effect of silver diamine fluoride (SDF) application on the microshear bond strength (MBS) of glass-ionomer cements (GIC) to caries-affected dentin (Part 1) and dentin cleaning methods to reduce SDF's potential effect on MBS (Part 2).
For Part 1, 56 extracted human teeth were randomly divided into eight groups with GIC, 38% SDF application and dentin substrate. Samples of artificial caries-affected human dentin were treated or not with 38% SDF and restored with conventional or resin-modified GIC. The same procedures were performed in sound dentin tested for MBS test after 24 hours. In Part 2, different dentin cleaning agents (water, aluminum oxide, and pumice slurry) were tested after SDF application. The procedure was performed on the group that presented the worst values for MBS in Part 1. Fracture mode was evaluated under scanning electron microscope. Data were statistically analyzed by ANOVA.
MBS was affected by the presence of caries and the type of material, with the conventional GIC the most affected (P< 0.05). Pumice slurry was superior in comparison to the other agents in cleaning SDF-treated dentin. Fracture evaluation showed more mixed failures in all the groups.
Clinicians should have caution when selecting the glass-ionomer cement (GIC) for restorations in silver diamine fluoride (SDF)-treated dentin. The mechanical properties of conventional GIC restorations were more affected than resin-modified GICs. Pumice slurry was the most effective cleaning method to minimize the negative effect of SDF on dentin.
Clinicians should have caution when selecting the glass-ionomer cement (GIC) for restorations in silver diamine fluoride (SDF)-treated dentin. The mechanical properties of conventional GIC restorations were more affected than resin-modified GICs. Pumice slurry was the most effective cleaning method to minimize the negative effect of SDF on dentin.
To evaluate the surface roughness and hardness of thermopolymerized acrylic resin incorporated with nanostructured silver vanadate (AgVO3) subjected to saliva and beverages.
The 128 specimens (5×5×2 mm) were prepared in thermopolymerized acrylic resin, according to the AgVO3 concentrations (n=32) 0%, 2.5%, 5% and 10%. The roughness and hardness were analyzed before and after immersion in saliva, Coca-Cola, orange juice and red wine, for 12 and 24 days. 2-way ANOVA and Bonferroni test (α= 0.05) were performed.
After 12 days, Coca-Cola caused the highest roughness increase in the 2.5% group. The 10% group with saliva presented a higher roughness increase (P= 0.009). The control presented a decrease in roughness when in beverages (P< 0.05). BI3812 After 24 days, orange juice and Coca-Cola produced a higher decrease in roughness in the control group (P< 0.05). After 12 days, saliva and wine produced a higher decrease in hardness of the 2.5% group (P< 0.05). Coca-Cola produced a decrease in hardness and wine an increase in hardness in the group with 10% AgVO3 concentration (P< 0.05). After 24 days, the group with 2.5% presented the highest decrease in hardness (P< 0.05). The immersions produced decreased hardness in the acrylic resin. Initially, there was an increase in roughness, however, over time, it decreased.
The control of oral biofilm is fundamental for the maintenance of the patient's oral health; however the incorporation of antimicrobial nanomaterial into prosthetic materials frequently exposed to saliva and beverages in the oral cavity interfered with the physical-mechanical properties of the products tested.
The control of oral biofilm is fundamental for the maintenance of the patient's oral health; however the incorporation of antimicrobial nanomaterial into prosthetic materials frequently exposed to saliva and beverages in the oral cavity interfered with the physical-mechanical properties of the products tested.
To evaluate in vitro the effect of a continuous mechanical polishing protocol, performed in different periods, on the surface roughness of acrylic resin teeth subjected to toothbrushing (Br).
Artificial acrylic teeth (n=30) were randomly divided into three groups according to the polishing protocol and toothbrushing (Br) Br; Br+Pol15 (Br associated with a biweekly polishing); Br+Pol30 (monthly polishing). Br group was subjected to a total of 89,000 brushing cycles. Polishing was performed by applying aluminum oxide paste to the specimens with a felt wheel coupled to an electric motor (5 seconds, 3,000 rpm) after each 741 and 1482 brushing cycles for Br+Pol15 and Br+Pol30 groups, respectively. A contact profilometer and an analytical balance were used to measure surface roughness and mass changes before (T0) and after 1, 2, 3, and 5 years (T4) of simulated toothbrushing. Scanning electron microscopy (SEM) images were obtained. Differences among groups were tested by means of two-way ANOVA/Bonferroni tests frequent mechanical polishing protocol could increase clinical performance and extend the lifespan of these appliances. Furthermore, a polishing protocol by means of a simple technique could be employed by patients in a home environment.
To examine the acid resistance of experimental toothpaste containing different wt% of surface pre-reacted glass-ionomer (S-PRG) filler.
Hydroxyapatite (HAP) pellets were treated with toothpaste containing 0, 1, 5, 10, 20, or 30 wt% S-PRG filler for 5 minutes. A demineralization and remineralization cycle was repeated for 7 days. The demineralized depths of the pellets were measured using a surface roughness analyzer. The crystallinity of both HAP and dicalcium phosphate dehydrate (DCPD) after the S-PRG treatment was measured by a powder X-ray diffraction (XRD) analysis. Fluoride gel (9,000 ppmF) was used for comparison.
The demineralizd depth decreased with increases in the S-PRG filler concentration. The demineralized depth with the 30 wt% S-PRG treatment (4.6 µm ± 2.0) was slightly greater than that with the fluoride gel (3.3 µm ± 0.5), but not significantly different (P< 0.05). However, significant differences were observed in demineralized depths between the fluoride gel and the other wt% of S-PRG tested (P< 0.05). In the XRD analysis, no crystallinity changes were noted in HAP or DCPD after the S-PRG or fluoride gel treatments. The formation of calcium fluoride was not detected in any treatment group.
The results demonstrated the effectiveness of the toothpaste containing 30 wt% S-PRG filler for inhibiting the demineralization of HAP pellets. However, the toothpaste containing S-PRG filler prevented demineralization less effectively than the fluoride gel.
The results demonstrated the effectiveness of the toothpaste containing 30 wt% S-PRG filler for inhibiting the demineralization of HAP pellets. However, the toothpaste containing S-PRG filler prevented demineralization less effectively than the fluoride gel.
evaluate the influence of an erbium, chromium yttrium, scandium, gallium, garnet (Er,CrYSGG) laser using multiple tip types, on the removal of retained cement on a titanium implant surface.
Nine titanium dental implants were coated with a non-eugenol resin composite implant cement. An Er,CrYSGG device at a wavelength of 2,780 nm was fitted sequentially with three laser fiber tips (1) 6 mm long, 600 µm diameter end-firing, quartz; (2) 9 mm long, Radial-Firing Perio Tip, 500 µm diameter, quartz; and (3) 18 mm long Side-Firing Tip, 800 µm x 300 µm, sapphire. Irradiation on the implant surfaces was performed in short pulse mode (140 µsec pulse duration) with output power of 1.5 W, 50% water, 40% air, and either (1) 15 Hz, 100 mJ/pulse; (2) 30 Hz, 50 mJ/pulse; or (3) 40 Hz, 37.5 mJ/pulse. Three trials each were completed for each of three different fiber tip types for a total of 27 trials (three trials for each of the nine groups).
All samples in Groups 1-6 demonstrated complete removal of cement from the imlarge number of ailing and failing implant cases. This study offers one solution to the problem of peri-implantitis, especially if caused by retained cement. Optimal laser settings are proposed for surface decontamination and treatment.
As the presence of peri-implantitis continues to increase in numbers and severity, it is imperative to have a predictable treatment protocol to address the large number of ailing and failing implant cases. This study offers one solution to the problem of peri-implantitis, especially if caused by retained cement. Optimal laser settings are proposed for surface decontamination and treatment.
To evaluate the wear in vitro of a new ion-releasing powder/liquid polymer resin in relation to that of glass-ionomer derivatives and conventional composites.
Flat specimens (eight per material) of the ion-releasing powder/liquid polymer resin Cention N, five resin-modified glass-ionomer cements [ChemFil Rock, Equia Fil (with and without coating), Fuji II, Photac Fil, Riva], six conventional glass-ionomer cements (Fuji IX, Fuji IX GP, Ionofil Molar, Ketac Fil Plus, Ketac Molar, Ketac Universal), and two popular conventional resin composites (CeramX, Filtek Z350 XT) were processed and luted to aluminum holders. After storage in water at 37°C for 24 hours, the specimens were polished to 2,500 grit and subjected to the Ivoclar wear method, which mainly simulates attrition wear using a commercially available chewing simulator. A standardized stylus made of pressable ceramic (IPS Empress) hits flat specimens 120,000 times with a 5 kg weight and a lateral movement of 0.7 mm under constant exchange of water at dould be chosen over resin-modified or conventional glass-ionomer cements.
For the restoration of posterior Class II and large Class I restorations, resin-based materials should be chosen over resin-modified or conventional glass-ionomer cements.
This study aimed to determine the relationship between enamel developmental defects (DDEs) and children's oral symptoms in the early and late mixed dentition in a hierarchical approach.
Population-based cross-sectional study of 772 children. Calibrated dental examiners examined for DDEs, malocclusion, and dental caries. Parents answered questions related to the socioeconomic condition of the family. The Child Perception Questionnaire (CPQ₈₋₁₀) was used to identify oral symptoms as the outcome variable. Analysis was adjusted in a backward stepwise hierarchical multiple logistic regression model.
Symptoms were predicted by being female, having a father with low education and having DDEs in the upper first molars (ORs = 1.42; 95% CI 1.06-1.89; 1.46 1.10-1.96 and 2.02 0.99-4.05 respectively).
DDEs are associated with oral symptoms in Brazilian children.
DDEs are associated with oral symptoms in Brazilian children.
