No abstract

This study evaluated the effect of different finishing-polishing protocols on surface roughness, gloss, morphology and biaxial flexural strength of pressable fluorapatite glass ceramic. Thirty ceramic discs (12x1 mm) were produced and divided into five groups (n=6): CT: control (glaze); DA: fine grit diamond bur; DG: DA + new glaze layer; DP: DA + felt disk with fine grit diamond paste; DK: DA+ sequential polishing with silicon abrasive instruments, goat hair brush and cotton wheel. The specimens were analyzed for surface roughness (Ra) under profilometry and atomic force microscopy (AFM). Gloss was measured with spectrophotometry and micromorphology with scanning electron microscopy (SEM). Flexural strength was assessed by biaxial flexural strength test. Data were analyzed using one-way ANOVA and Tukey’s post hoc test (a=0.05). DK showed the lowest surface roughness values and DA presented the highest in the perfilometer analysis. No significant differences were observed in the AFM for the CT, DG and DK groups, which presented the lower surface roughness; DA and DP had the higher Ra values. The DA, DP and CT showed the lowest surface gloss values, and the reflectance was significantly different from those observed for DK and DG groups. SEM analysis revealed the smoothest surface for DK group, followed by DG and CT groups; DA and DP groups exhibited variable degrees of surface irregularities. No significant differences were observed among groups for the biaxial flexural strength. The polishing protocol used in DK group can be a good alternative for chairside finishing of adjusted pressable fluorapatite glass ceramic surfaces.

Dry powder coating is a powerful method for modifying the surface properties of particles whilst retaining their essential bulk properties. The coating of a host powder by guest particles can be achieved via different means ranging from simple stirring together of the two components, to high energy impact coating in devices such as a Nara Hybridizer or Turbula Mixer. The quality of the powder coating resulting from such methods is an important parameter, which depends both on the force of the mechanical action used, and also the physico‐chemical interactions between the host and guest particles. Here, a method for evaluating the strength of host‐guest interactions based on particle size analysis using a standard Malvern Mastersizer with dry powder feed is presented. Basically, the liberation of small guest particles from host particles can be achieved by increasing the air pressure, and the presence of liberated fine particles mixed with guest particles can be detected from differences in volume and number distributions. Complementary examination is undertaken using an environmental scanning electron microscope (ESEM). This technique has been used to evaluate the interaction strength of a coating of hydrophobic magnesium stearate on a herbal extract (Harpagophytum). It is shown that effective coating can be achieved by three different means: simple stirring, a Turbula Mixer and by using a Nara Hybridizer. The respective strength of the coatings is greater with increasing mechanical force used for the process. The method is proposed as a simple means of evaluating powder‐powder coating processes.

Objective: The aim of this study was to perform an acid wear properties review (pH, entitlement and buffering effect) of diets that can influence dental and restorative aging. Methodology: Manuscripts from the Pubmed database were collected. The search terms were: “Dental erosion”, “Erosion”, “Food habits”, “acidity”, “tooth enamel solubility”, “carbonated drinks”, “hydroxyapatite” and “alcoholic beverage consumption” between the years of 1995 and 2020. Result: 755 manuscripts were initially obtained, but after analyzing the inclusion and exclusion criteria, 15 manuscripts were selected at the end. After analyzing the 15 manuscripts included in the literature review, the results of the study showed that most of the diets evaluated had a pH lower than 5.5, except for coffee and mineral water. The soft drinks and Kombucha had lower pH values and therefore more corrosive potential. Conclusion: Based on the results of this study, it may be concluded that most of the diets evaluated present a corrosive potential for dental structure and restorative materials.

Colorectal cancer (CRC) is currently the third most common cancer within the United States among both males and females, with increasing rates occurring in younger individuals compared to the past. Multiple environmental and social aspects including diet may be contributing to this increase in CRC rates. The aim of this review is to examine foods containing high fructose corn syrup, processed meats, and red meats which have shown to be linked to an increase in incidence of CRC. These foods can be a cause for disruption in a healthy microbiome leading to dysbiosis, which can have downstream effects on CRC formation. With the current data showing evidence of potential triggers and associations leading to CRC, more studies are needed to help directly link these dietary components and their pathways to cancer formations.