Davidsonhaahr6166

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). 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. Oxaliplatin Differences among groups were tested by means of two-way ANOVA/Bonferroni tests (P= 0.