Incorporation of nano-hydroxyapatite into experimental resin infiltrant and its performance on color stability and reinforcement in demineralized enamel: in vitro study

Author(s)

Jade Laísa Gordilio Zago

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2023-06-30

Examining board members

Giselle Maria Marchi; Linda Wang; Waldemir Francisco Vieira Junior

• Advisor: Giselle Maria Marchi

Abstract

The aim of the study was evaluate the influence of 10% nanohydroxyapatite penetration in an experimental resinous infiltrant, on color stability and cross-sectional microhardness, when compared to experimental infiltrant, Icon® commercial resin infiltrant and untreated enamel surfaces. 135 enamel blocks of bovine teeth were obtained in the 4x4 mm pattern. They were subjected to demineralization/remineralization (des-re) cycles for 8 days and subsequently divided into 5 groups: H: healthy; MB: white spot; I: Icon®; E: experimental; EH: experimental containing 10% nanohydroxyapatite. Then, the groups were infiltrated or not according to respective groups. For color evaluation (n=15), CIEL*a*b* values were obtained using a spectrophotometer at times: T0 (before immersion), T1 (14 days after immersion on coffe) and T2 (28 days after). For staining, 1.5l of coffee solution was used, changed daily for 28 days and data obtained were applied in CIEDE2000 formula. Cross-sectional Knoop microhardness was performed in halves obtained from the specimens (n=12) and 30 readings were performed on each sample: 3 columns 200 ?m apart from each other, and each containing 10 readings every 30 ?m from the surface. The hardness data obtained in groups MB, I, E and EH were applied in the mineral loss formula (?S). For Optical Microscopy of Polarized Light, 5 halves of each group (n=5) were used and polished until they reached a thickness of 0.1mm and taken to Microscopy. Shapiro-Wilk was applied for color stability and mineral loss, then analysis of variance (one-way ANOVA), followed by the Post Hoc test by Bonferroni and Tukey, respectively, and the significance level set at 5%. In the results of color stability, regardless of time, there was no significant difference between groups H and MB; in 14 days, H and MB differed statically from infiltrated groups I, E and EH and, in 28 days, MB differed from all infiltrated groups, and H differed from E and EH. The variation between 14 and 28 days was not significant for any group. In terms of mineral loss, MB group showed a significant difference in relation to groups I and EH, but it did not differ from group E. I and EH did not differ statistically. Images obtained was possible to observe initial lesions in the MB group and superficial deposition of material in the infiltrated groups. In conclusion, the experimental groups of resinous infiltrants performed similarly to the commercial ones in terms of color variation, but they had a greater variation than that of untreated surfaces; in the cross-sectional microhardness, it was possible to notice that groups I and EH presented smaller mineral loss, suggesting a reinforcement in dental structure, while the groups MB and E presented greater mineral loss (AU)

• FAPESP's process: 21/14881-5 - Avaliação da estabilidade de cor e microdureza seccional em infiltrantes resinosos
• Grantee: Jade Laisa Gordilio Zago
• Support Opportunities: Scholarships in Brazil - Master