Analysis of the dental staining potential of color additives for use in whitening gels

• Grant number: 24/18345-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Carlos Rocha Gomes Torres
• Grantee: Sofia Fernandes Tosta
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Associated research grant: 22/04270-1 - Development of inovative formulations to optimize the efficacy and safety of dental bleaching, AP.TEM

Abstract

The objective of this study is to evaluate the staining potential of dyes and pigments for use in bleaching gels. For this analysis, 80 enamel/dentin specimens in the form of discs will be prepared. The specimens will be analyzed for cracks in the enamel using the transillumination process. The specimens will then be embedded in bisacrylic resin color B1, in order to cover and protect the dentin and the lateral area of ¿¿the enamel from the action of the treatment. The surface will be polished with P1200, P2000 and P4000 grit sandpaper, followed by a diamond suspension with 3 ¿m particles and finally a diamond suspension with 1 ¿m particles, using polishing felts appropriate for each grit. The specimens will be placed in numbered Eppendorf tubes containing 2 ml of artificial saliva, and will remain for 7 days for rehydration, allowing a correct evaluation of the initial color. The initial color of each specimen will be assessed using a CM-5 reflectance colorimetric spectrophotometer (Konica Minolta, Osaka, Japan). The instrument will be adjusted to take three consecutive readings to obtain an average of the L* a* and b* values ¿¿per specimen. After the readings are taken, the specimens will be removed from the instrument and stored in corresponding Eppendorf tubes containing 2 ml of artificial saliva. To analyze the staining effect, the specimens will be removed from the artificial saliva and placed on silicone supports. The surface will be dried using a piece of absorbent paper. Solutions containing 0.2% of the dyes patent blue V (FD&C), patent blue V, brilliant blue no. 1 (FD&C), indigo carmine blue no. 2 (FD&C), brilliant black (FD&C), spirulina extract (Linablue), and the pigments blue 78 and blue 63 will be prepared. The pH will be adjusted to 7 using a 10 M sodium hydroxide solution. A volume of 20 ¿l of each solution will be applied to the enamel surface and remain in contact with it for 45 minutes, inside a chamber with a controlled atmosphere maintained at a temperature of 37°C and relative humidity of 65%. The surfaces will then be washed with running deionized water and immersed again in artificial saliva. The color will be measured immediately afterward, returning to the artificial saliva inside an Eppendorf tube, inside an oven at 37°C. After 7 days, the color will be evaluated again. The calculation of the variation in color perception (¿E00) will be performed between the initial color and immediately after exposure to dyes and pigments, and between the initial color and after 7 days. The perceptibility limit of the color change will be 0.8. The data obtained will be analyzed statistically.