Effects of different polishing procedures on the color stability of recent resin composites.

PURPOSE: To evaluate different polishing methods' effects on the color stability of recent resin composites. METHODS: 160 samples for color stability evaluation and 40 samples for the degree of conversion evaluation were prepared with four different resin composites [Harmonize (H), Filtek Universal (F), Omnichroma (O), Essentia Universal (E)] and light cured. For color stability evaluation, samples prepared from each resin composite were divided into four groups: three polishing procedures and a control group. The ΔE00 was calculated between initial, and after immersion in coffee solution for 12 days. The degree of conversion was evaluated with Fourier Transform Infrared Spectroscopy. The statistical analysis of ΔE00 values was made with the two-way ANOVA, Tukey HSD, and Tamhane's T2 tests. One-way ANOVA and Tukey HSD tests were used to compare the degree of conversion values (P< 0.05). RESULTS: In all composite groups, mylar (control) groups had the highest ΔE00, and no differences between other polishing procedures. According to the polishing procedures, Omnichroma showed the highest ΔE00 values (on mylar groups O vs F, P< 0.001; O vs H, P< 0.001; O vs E, P< 0.001). There was a significant difference between the composite groups in terms of the degree of monomer conversion (P< 0.05). Omnichroma showed, significantly, the highest discoloration. CLINICAL SIGNIFICANCE: Different polishing procedures showed effective performance on current composite surfaces. Omnichroma resin composite showed higher color change than composites with similar properties.

The Effect of In-Office Bleaching with Different Concentrations of Hydrogen Peroxide on Enamel Color, Roughness, and Color Stability.

The aim of this study is to evaluate the effectiveness of in-office bleaching in esthetic dentistry on the roughness and color stability of the enamel surface, using different concentrations of hydrogen peroxide (HP). Fifty human incisors were randomly divided into 5 groups (n = 10). No bleaching was performed in the control group. For these groups, concentrations of 40% HP with fluoride (F), 35% HP with calcium (Ca), 25% HP with nano-hydroxyapatite (nHA) and 18% HP with nHA were used for bleaching in the test groups. Surface roughness was assessed at baseline after bleaching occurred. Color measurements were first obtained at baseline, then after the first and second sessions of bleaching, and, finally, after the staining protocol. Scanning electron microscopy and atomic force microscopy were performed. Statistical analysis was conducted with a one-way ANOVA, followed by a post hoc Tukey's test and a paired-samples t-test (p < 0.05). All the bleaching gels used exhibited a similar color change (p > 0.05). Bleaching gels containing 18% HP with nHA and that containing 35% HP with Ca caused less surface roughness of the enamel. Of these concentrations, 25% HP with nHA caused the most surface roughness and no significant difference was observed, compared with 40% HP with F. The highest coloration after bleaching was observed in 40% HP with F and 25% HP with nHA. The lowest coloration was obtained in 35% HP with Ca and 18% HP with nHA but no significant difference was observed between them and the control group. A concentration above 18% HP does not increase the bleaching effectiveness. The results show that 18% HP with nHA and 35% HP with Ca resulted in the least increase in enamel surface roughness when compared to high-concentrate HP; however, it also prevented recoloration after bleaching.

Instrumental and visual evaluation of the color adjustment potential of different single-shade resin composites to human teeth of various shades.

OBJECTIVE: The study aims to evaluate the color adjustment potential (CAP-I, CAP-V) of different single-shade resin composites. MATERIALS AND METHODS: The shades of 40 human incisors were determined using a spectrophotometer, with the teeth divided into four groups of the same shade (n = 10). The following single-shade resin composites were tested: Omnichroma, Charisma Diamond One, Vittra Unique, and Essentia Universal. The specimens were prepared as "dual" and "single." Standardized cavity preparations (diameter, 7 mm; depth, 2 mm) were prepared in human incisor teeth and then restored for dual specimens. Composite duplicates of human incisors were prepared with resin composites for single specimens (n = 10). The color match of these specimens to that of unrestored human incisors was compared, and the color difference (ΔE*) was calculated. Independent observers conducted a visual evaluation of the specimens and scored them. CAP-I and CAP-V values were determined. A one-way analysis of variance test was used for statistical analysis (p < 0.05). RESULTS: There was no statistically significant difference between the CAP-V and CAP-I values of the tested single-shade resin composites (p > 0.05). All the materials tested had acceptable color-matching potential. CONCLUSIONS: In terms of color matching, there were no significant differences between the different tooth shades of all the tested resin composites. CLINICAL RELEVANCE: Single-shade resin composites have acceptable CAP. The use of single-shade resin composites can reduce in-chair clinical times by minimizing the time spent on shade selection.

Color stability of bulk-fill resin composites exposed to caffeinated beverage: An in vitro study.

PURPOSE: To evaluate the in vitro color stability and surface properties of bulk-fill resin composites after exposure to coffee and cola. METHODS: Color stability was evaluated in a conventional resin composite (Filtek Z250) and three bulk-fill resin composites (Filtek One Bulk Fill, Tetric N-Ceram Bulk Fill, and Beautifil Bulk Fill as giomer). Color change (CIEDE 2000 ΔE00) was calculated after 12 days of immersion in distilled water (control), coffee, or cola (Diet Coke). Water sorption (%Wsp) and solubility (%Wsl) ratios were calculated for each material in each solution. One sample of each material from each condition was observed with scanning electron microscopy and atomic force microscopy. Generalized linear modeling and Bonferroni correction were used for ΔE00 value analysis. One-way ANOVA and Kruskal Wallis tests were performed to analyze %Wsp and %Wsl ratios. RESULTS: Tetric N-Ceram Bulk Fill showed the highest ΔE00 value in distilled water. Beautifil Bulk Fill had the highest ΔE00 value in coffee and cola. Beautifil Bulk Fill had the highest %Wsl ratio. Filtek One Bulk Fill and Tetric N-Ceram Bulk Fill had the highest and lowest %Wsp ratios, respectively. Coffee and cola exposure had surface property-disrupting and discoloration effects on both conventional and bulk-fill resins. CLINICAL SIGNIFICANCE: Acidic beverages could negatively affect the surface properties of bulk-fill and conventional resin composites. The usage of the giomer composite might have disadvantages in terms of esthetics.

Side effects of immune-checkpoint inhibitors: Can multiple side effects be seen in a patient?

INTRODUCTION: Nivolumab is a human immunoglobulin G4 monoclonal antibody that inhibits programmed cell death-1 activity by binding to the programmed cell death-1 receptors. Cancer cells express increased number of programmed cell death-1 ligands and this allows them to escape the cytotoxic effects of the T cells. Therefore, the negative programmed cell death-1 receptor signal regulates T-cell proliferation and activation is disrupted. However, this change in the activity of the T cells can cause them to lose their ability to recognize host cells. The immune response enabled by these agents has led to side effects, commonly known as "immune-related adverse events." CASE REPORT: We report a case of a 66-year-old male patient who was treated with nivolumab for recurrent renal cell carcinoma presented with hepatitis and adrenalitis. Three weeks after starting nivolumab, the patient had abdominal pain and weakness, and then aspartate and alanine transaminase levels were found to be elevated. MANAGEMENT AND OUTCOME: Hepatitis was predicted to be due to nivolumab, because other causes were excluded. He started using oral methylprednisolone and then, hepatitis improved. However, while receiving methylprednisolone treatment, fludrocortisone was started with the pre-diagnosis of adrenalitis due to the persistence of fatigue, weakness, and hyponatremia and hyperkalemia. With both treatments, the patient's symptoms and sodium and potassium level returned to normal. DISCUSSION: This case emphasizes the need for patient's education and awareness of immune-related adverse events, and the importance of understanding the management of life-threatening complications of the checkpoint inhibitors, because these side effects require prompt recognition and treatment.

Effect of different beverages on surface properties and cariogenic biofilm formation of composite resin materials.

The consumption of certain beverages may affect the physical and biological properties of resin composites (RCs) according to type. This in vitro study aimed to evaluate the surface properties and cariogenic biofilm formation in microhybrid and nanohybrid RCs after immersion in different beverages. The effects of four beverages (distilled water-control, tea, coffee, and cola) on two RCs (microhybrid and nanohybrid) were evaluated. Changes in the surface properties were evaluated for each group using surface roughness measurement (n = 10), scanning electron microscopy (SEM) (n = 4) observation, and energy-dispersive X-ray spectroscopy (EDX) (n = 5) analysis. In vitro Streptococcus mutans biofilm formation on the specimens of each group was determined using confocal laser scanning microscopy and SEM analysis (n = 14). The data were analyzed using two-way analysis of variance, with Bonferroni as a post-hoc test and Pearson's correlation (p < .05). Microhybrid RC presented more surface roughness (p = .014) and cariogenic biofilm formation (p = .040). The surface roughness (F = 0.733, p = .536) and cariogenic biofilm formation (F = 1.685, p = .181) values were not affected by the beverages. However, according to qualitative SEM and EDX measurements, these parameters varied depending on the beverage groups. No correlation was found between surface roughness and cariogenic biofilm formation (r = 0.135, p = .287). Microhybrid RCs had a rougher surface and a higher amount of cariogenic biofilm formation than nanohybrid RCs after being subjected to different beverages.