A Laboratory Manual for the Preparation of Chemical Reagents, Solutions and Special Indicators

A Laboratory Manual for the Preparation of Chemical Reagents, Solutions and Special Indicators. ETHIOPIAN BIODIVERSITY INSTITUTE, Microbial Biodiversity Directorate. This manual includes detailed view of the following: Laboratory Safety Precautions, Chemical Reagent Preparation, Buffer and Chemical Solution Preparation, Staining Solution Preparation, Indicators and Dye Solution Preparation, Preparation of Special Reagents, Known and Suspected List of Carcinogens and References.

Effect of brushing on colour stability of nanohybrid composite after immersion in brewed beverages – an in vitro study

Background and aims. In today’s world, everyone is mindful of one’s appearance and appreciates aesthetics. Of the various restorative materials available, composites are considered as the most aesthetic with good color stability. This study aims at finding the effect of brushing on the color stability of nanohybrid composite after being immersed in various beverages. Methods. Thirty disk specimens were prepared for each staining solution (N=30), with a total of 90 specimens. The disk specimens for each staining solution were then sub divided into 2 groups (N=15): brushing and non-brushing. After preparation, the specimens were soaked in distilled water for 24 hours in separate containers. Baseline color of the samples was evaluated using spectrophotometer. The samples were then immersed in tea, coffee or water. The groups of samples to be brushed were held in the mold and 20 strokes of brushing using an electronically powered toothbrush were done on each side of the disk sample. The color was re-evaluated after a period of 14 days. Results. When comparing among the three beverages, tea showed the highest ΔE*ab indicating greatest discoloration when compared to coffee and water. This can be graded as tea > coffee > water. However, statistically there was no significant difference between tea and coffee. When compared within tea, coffee, or water specimens the non - brushed specimens showed greater discoloration compared to the brushed specimens both clinically and statistically. Conclusion. When immersing the specimens in the solutions, tea showed more color change compared to coffee, making the specimens clinically unacceptable. However, brushing the specimens reduced the discoloration when compared to non–brushing, making the coffee specimens clinically acceptable.

GUS staining protocol v1

All the reagents for GUS staining are easy to use. Just mix the prepared X-gluc solution and buffer in proportion to form a GUS staining solution. This kit can prepare 50ml GUS staining solution.

COMPARING THE EFFECT OF LASER BLEACHING WITH HOME BLEACHING ON PAAN STAINED TEETH USING DIGITAL SPECTROPHOTOMETER

Introduction: The demand for tooth whitening has increased dramatically with the resulting development of new tooth whitening products and procedures. As it is a common scenario that the dentists come across paan stained teeth very regularly in dental practice, the need for this study is to compare if laser bleaching or three day home bleaching is effective for paan stained and give better treatment options for patients. Aim: To compare the effect of laser bleaching on paan stained tooth with home bleaching tooth using digital spectrophotometer Methodology: 20 extracted teeth were preserved in a solution of normal saline with 1% thymol crystals. The teeth were immersed in staining solution containing paan extracts for a period of two week. The specimens were evaluated for pre shades using VitaEasyShade. The stained specimens for paan respectively were divided randomly into 2 groups one for laser bleaching and other for home bleaching. POLA OFFICE + was applied on tooth and activated using the diode laser as per the manufacturer’s instructions for group 1. The bleaching was carried out with Philips Zoom Nitewhite for group 2. The second colour measurement of the specimens was made using VitaEasyShade. Conclusion: The results showed that laser bleaching was effective when compared to three day home bleach in paan stained teeth using digital spectrophotometer.

A Simple Nuclear Contrast Staining Method for MicroCT-Based 3D Histology Using Lead(II) Acetate

ABSTRACTX-ray microtomography (microCT) enables histological-scale 3D imaging of many types of biological samples, but it has yet to rival traditional histology for differentiation of tissue types and cell components. This report presents prima facie results indicating that a simple lead(II) acetate staining solution can impart preferential X-ray contrast to cell nuclei. While not strictly selective for nuclei, the staining reflects local cell-density differences. It can be applied in a single overnight treatment and does not require hematoxylin staining or drying of the sample. The stain is removable with EDTA, and it may enhance early calcifications. A basic protocol is given as a guide for further testing and optimisation.

Influence of Staining Solutions on Color Change and Enamel Surface Properties During At-home and In-office Dental Bleaching: An In Situ Study

SUMMARY The purpose of this in situ study was to evaluate the influence of staining solutions (coffee and cola) on the color change, microhardness, roughness, and micromorphology of the enamel surface during at-home and in-office dental bleaching. One hundred and thirty-five enamel bovine blocks were prepared to perform the evaluations. Fifteen volunteers used an intraoral appliance with nine enamel blocks for 15 days. The enamel blocks were randomly assigned among the different groups according to the three treatments: in-office bleaching with high hydrogen peroxide concentration (Opalescence Boost PF 40%, Ultradent) for 40 minutes in three sessions (first, eighth, and 15th days of treatment), at-home bleaching with low carbamide peroxide concentration (Opalescence PF 10%, Ultradent) for 60 minutes daily for 15 days, and a control group (no bleaching agent applied). The enamel blocks were immersed daily in different staining solutions (coffee or cola) for 30 minutes for 15 days or were not submitted to staining (control) to obtain a factorial scheme (3×3) of the dental bleaching treatment and staining solution (n=15). The microhardness analyses (Knoop), roughness evaluations (Ra), surface micromorphological observations, and color measurements (using the CIELAB system and the VITA Classical scale) were made before and after the bleaching treatments to assess immersion in staining solutions. Mixed model tests showed that there was a decrease in enamel microhardness after exposure to cola compared with coffee and the control group (p<0.0001) for both bleaching techniques. Roughness was higher for the cola groups (p<0.0001), and there was no significant difference between the coffee and the control groups. Generalized linear models showed that when no staining solution was applied, lighter color scores were found for the VITA Classical scale (p<0.0001). Without the staining solutions, there was an increase in luminosity (ΔL) (p=0.0444) for in-office bleaching. Lower values of Δa (p=0.0010) were observed when the staining solutions were not used. The Δb (p=0.3929) did not vary significantly between the bleaching agents, but when cola was applied, the values were significantly higher than for the control (p=0.0293). Higher values of ΔE (p=0.0089) were observed for in-office bleaching without staining solutions, while lower values of ΔE were observed for the in-office associated with coffee immersion. Regardless of whether being submitted to bleaching, the enamel stained with cola showed a decrease in microhardness, an increase in roughness, and changes in the micromorphology. The efficacy of the bleaching agents was greater when no staining solution (cola or coffee) was used, and in-office bleaching showed greater color change than the at-home bleaching technique.