Mechanical Properties of Orthodontic Cements and Their Behavior in Acidic Environments

Effect of an Effervescent Multivitamin on Color and Surface Roughness of Micro-Hybrid Dental Resin Composites

The use of multivitamins has become widespread globally, yet there is a scarcity of studies investigating their impact on resin composite restorations. This study aimed to evaluate the effect of an effervescent multivitamin tablet on micro-hybrid dental resin composites' surface roughness and color. Fifty disc-shaped samples (8 × 2 mm, shade A2; n = 10) were prepared and polished using five different micro-hybrid resin composites (Pergamon, Dentac, Turkey; Estelite Posterior, Tokuyama, Japan; Geanial Anterior, GC, Japan; Charisma Opal, Kulzer, Germany; Beautifil II, Shofu, USA). Samples were immersed in 200 mL water to one effervescent multivitamin tablet (Redoxon Triple Action, Bayer) at 24 °C for 2 min a day in 24 h intervals for 30 days. All samples' surface roughness (Ra) and ΔE(L*a*b) measurements were recorded at the beginning and end of the 30 days. The Wald chi-square and a two-way ANOVA were used for statistical analysis (significance level p < 0.05). The resin composite type and exposure to the multivitamin had a statistically significant effect on Ra values (p < 0.05). The resin composite type had a statistically significant effect on ΔE values, likely due to the higher mean value of BII (p = 0.040). The surface roughness and color of resin composites can be affected by multivitamins with a pH value of 3.0. Therefore, it is important to consider the patient's routine vitamin intake during resin composite selection. Additional research is required to explore the properties of different dental restorative materials.

Shear bond strength of a RMGIC for orthodontic bracket bonding to enamel

OBJECTIVE

To evaluate the shear bond strength (SBS) of a restorative resin-modified glass ionomer cement (RMGIC) for orthodontic bracket bonding.

MATERIALS AND METHODS

One hundred twenty-one human teeth were randomly divided into 11 groups (n = 11) according to the surface treatment applied (H3PO4 ± Transbond Plus (TSEP) or Scotchbond Universal (SU)), and the adhesive used (Riva LC HV (RIVA), Fuji Ortho (FUJI), and Transbond XT (TXT)). For each sample, a metal button was bonded. SBS tests were performed at 1 week and debonded specimens were observed for failure modes determination. One-way ANOVA followed by Tukey's post hoc test was used to compare SBS differences and Fisher's exact test to analyze the failure modes (p < 0.05).

RESULTS

TSEP + FUJI and H3PO4 + SU + TXT showed the highest SBS values while H3PO4 + TSEP + RIVA showed the lowest value. Cohesive failure and mixed failure were found in the groups with SU and TXT and adhesive failure in the other groups.

DISCUSSION/CONCLUSIONS

The bonding of orthodontic attachments to enamel could be performed with any of the three materials studied. The use of a universal adhesive in the bonding protocol could optimize the adhesion values. Clinical studies would be needed to confirm the results obtained.

Chemical and Structural Assessment of New Dental Composites with Graphene Exposed to Staining Agents

Among the newest trends in dental composites is the use of graphene oxide (GO) nanoparticles to assure better cohesion of the composite and superior properties. Our research used GO to enhance several hydroxyapatite (HA) nanofiller distribution and cohesion in three experimental composites CC, GS, GZ exposed to coffee and red wine staining environments. The presence of silane A-174 on the filler surface was evidenced by FT-IR spectroscopy. Experimental composites were characterized through color stability after 30 days of staining in red wine and coffee, sorption and solubility in distilled water and artificial saliva. Surface properties were measured by optical profilometry and scanning electron microscopy, respectively, and antibacterial properties wer e assessed against Staphylococcus aureus and Escherichia coli. A colour stability test revealed the best results for GS, followed by GZ, with less stability for CC. Topographical and morphological aspects revealed a synergism between GZ sample nanofiller components that conducted to the lower surface roughness, with less in the GS sample. However, surface roughness variation due to the stain was affected less than colour stability at the macroscopic level. Antibacterial testing revealed good effect against Staphylococcus aureus and a moderate effect against Escherichia coli.

Synthesis, Physicochemical Characterization and Applications of Advanced Nanomaterials

This Special Issue highlights the last decade's progress regarding new nanostructured materials. In this regard, the development of nanoscale syntheses and innovative characterization tools that resulted in the tailored design of nanostructured materials with versatile abilities in many applications were investigated. Various types of engineered nanostructures, usually metal nanoparticles or nanoporous metal oxides, have been synthesized for various applications. This Special Issue covers the state-of-the-art of advanced nanoparticles in many disciplines (chemistry, pharmacy, nanomedicine, agriculture, catalysis, and environmental science). The crystallite sizes depended on the annealing temperature and type of doping ion. A combination of rigid and soft particles could simultaneously enhance both the tensile properties and the fracture toughness, which could not be achieved by the single-phase particles independently. The surface charge and in vitro corrosion resistance are key parameters characterizing biomaterials in the interaction of the implant with the biological environment. Solar energy in the presence of a photocatalyst can be effectively converted into electricity/fuel, break down chemical and microbial pollutants, and help water purification. The saturation magnetization, remanent magnetizations, coercivity, and anisotropy were found to depend on the doping ion, annealing temperature, and particle size. The efficiency of the photocatalysis reaction depends on several factors, including light absorption capacity/light intensity, the type of photocatalyst used, the concentration of a photocatalyst and contaminant particles, the pH of the reaction medium, etc. The variety of color pigments and coloring properties of the targeted application in the ceramic industry was also of interest.