BackgroundAn ameloblastoma is a benign odontogenic neoplasm with aggressive behaviour and high recurrence rates. The increased expression of matrix metalloproteinases (MMPs) has been reported in ameloblastomas. In the present study, we hypothesised that epigenetic alterations may regulate MMP expression in ameloblastomas.MethodsWe investigated the methylation status of the genes MMP-2 and MMP-9 in addition to mRNA transcription and protein expression in ameloblastomas. Methylation analysis was performed by both methylation-specific polymerase chain reaction (MSP-PCR) and restriction enzyme digestion to evaluate the methylation profile of MMP-2 and MMP-9 in 12 ameloblastoma samples and 12 healthy gingiva fragments, which were included as controls. Furthermore, we investigated the transcription levels of the genes by quantitative reverse-transcription PCR (qRT-PCR). Zymography was performed to verify protein expression in ameloblastomas.ResultsThe ameloblastomas showed a high frequency of unmethylated MMP-2 and MMP-9, whereas the healthy gingival samples presented a sharp prevalence of methylated MMPs. Higher expression levels of MMP-9 were found in ameloblastomas compared to healthy gingiva. However, no significant differences in the MMP-2 mRNA expression between groups was found. All ameloblastomas showed positive expression of MMP-2 and MMP-9 proteins.ConclusionsOur findings suggest that expression of MMP-9 is increased in ameloblastomas and is possibly modulated by unmethylation of the gene.
Background The increasing demand of tooth bleaching has also increased the need of researches focusing on the durability of the resultant color. The aim of this study was to evaluate the effect of a system based on calcium silicate, sodium phosphate and sodium monofluorophosphate (Regenerate™) on color maintenance of bleached enamel considering two waiting times for the contact with a cola drink. Material and Methods This in vitro study was performed on bovine enamel specimens (n = 100), bleached with 35% H2O2 and treated with: G1 Distilled water; G2 Artificial saliva; G3 RegenerateTM Serum and Toothpaste; G4 RegenerateTM Toothpaste; G5 RegenerateTM Serum. The groups G3, G4 and G5 received one application of the respective products for 3 min, in 3 consecutive days. The color parameters (ΔE, L*, a*, b*) were evaluated by spectrophotometry before and after bleaching and after surface treatments and immersion (15min) in cola drink, on the waiting times of 24 hours (T1) and 7 days (T2). The effect of surface treatments and waiting times was evaluated by Two-Way ANOVA, Kruskal-Wallis, Wilcoxon and T test ( p <0.05). Results There was no significant effect of the surface treatments ( p =0.57), waiting times ( p =0.97) and their interaction ( p =0.47) considering ΔE. The analysis of repeated measures of the color coordinates L*, a* and b* showed a decrease of chromaticity (a*, b*) for G3, G4 and G5 and an increase of lightness (L*) for G5, after immersion in cola drink, suggesting some protection against bleached enamel pigmentation. Conclusions RegenerateTM has a potential protective effect on bleached enamel color maintenance. The waiting times of 24 hours and 7 days for the contact with the cola drink did not influence bleached enamel color maintenance. Key words: Tooth bleaching, hydrogen peroxide, spectrophotometry, pigmentation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.