RESUMEN
@#Histone acetylation and methylation can affect chromatin conformation and regulate a variety of biological activities. Abnormal histone acetylation and methylation modifications are related to the occurrence and development of a variety of oral diseases. Histone acetylation and methylation increase or decrease in an orderly manner to regulate the development of teeth. Fluoride ions can destroy the balance between histone acetylation and methylation, which may be related to the occurrence of dental fluorosis. In addition, histone acetylation and methylation are involved in the regulation of oral inflammatory diseases. In the inflammatory microenvironment, the expression of histone acetyltransferase GCN5 decreases, and the expression of Dickkopf 1 (DKK1) decreases, activating the Wnt/β-catenin pathway and ultimately inhibiting the osteogenic differentiation of periodontal ligament stem cells. Enhancer of zeste homolog 2 (EZH2) and H3K27me3 levels were decreased in inflamed dental pulp tissues and cells. EZH2 inhibition inhibited the expression of interleukin (IL)-1b, IL-6 and IL-8 in human dental pulp cells under inflammatory stimulation. Histone acetylation/methylation modifications can interact with multiple signaling pathways to promote the occurrence and development of oral tumors and are related to the high invasiveness of salivary gland tumors. Small molecule drugs targeting histone acetylation and methylation-related enzymes can regulate the level of histone methylation/acetylation and have shown potential in the treatment of oral and maxillofacial diseases. For example, the histone deacetylase inhibitor vorinostat can inhibit the secretion of inflammation-related cytokines; it also promotes the maturation of odontoblasts and the formation of dentin-related matrix, demonstrating its potential in pulp preservation. Understanding the role of histone acetylation/methylation modifications in the occurrence and development of oral diseases will help promote research on epigenetic modifications in oral diseases and provide new perspectives for disease diagnosis and treatment.
RESUMEN
@#Oxidative stress is closely associated with the development of oral diseases such as caries, periodontitis and endodontitis. The accompanying oxidative stress during inflammation could aggravate tissue damage. However, numerous studies have shown that some dental materials, such as composite resins, bleach, drugs for root canal irrigation and dental implants, can give rise to abundant free radicals, which have adverse effects on peripheral tissues. Therefore, it is essential to supplement with extra antioxidants against free radicals. Plant-derived natural antioxidants have attracted great attention in biomedicine because of their excellent biocompatibility and easy access. This paper focused on the redox imbalance in the oral cavity and the application of natural antioxidants to oral therapy and their modification of dental materials. Current research shows that by constructing polyphenol-based metal organic nanoenzymes or adding vitamins and polyphenols to bionic hydrogels, the safety and utilization rate of antioxidants can be significantly improved. However, these polymer delivery systems have problems such as poor degradability, hepatotoxicity and nephrotoxicity, and the research is still in its infancy. In terms of material modification, it is crucial to choose the type and ratio of natural antioxidants and raw materials, as well as appropriate modification methods. A strong chemical bond between the antioxidant and the raw material may lead to the failure of antioxidant release from the modified composite, lowering the antioxidant activity. At the same time, the selection of polyphenols rich in pyrogallol functional groups can retain more free phenolic hydroxyl groups after chemical modification, which is conducive to greater antioxidant activity by the implant materials. Although research on natural antioxidants in oral therapy has made progress, there is a lack of data supporting clinical trials and long-term application effects, and further research is still needed.
RESUMEN
Objective@#To compare the color stability of Biodentine and mineral trioxide aggregate (MTA) within the blood environment in vitro and to further investigate the underlying reasons for such color instability. @*Methods @#We first generated Biodentine and MTA discs with a diameter of 5 mm and a height of 3 mm. 24 discs of each material were randomly divided into two groups: the deionized water group and the defibrinated sheep blood group. Discs of each group were immersed for 1 day or 7 days before assessments. First, all discs were photographed to directly compare the discoloration of Biodentine and MTA. The color degree of the two materials was tested by a spectrophotometer. Then, the high-resolution morphological characteristics were observed by scanning electron microscopy. Finally, the chemical contents of each element in the material were measured by energy-dispersive spectroscopy.@*Results @#Compared to immediately after stripping, a change in the brightness of discs after immersion in defibrinated sheep blood for 1 day was observed only in MTA. On the 7th day after being immersed in blood, the colors of both the Biodentine and MTA discs darkened and turned deep red, but the darkness of the MTA discs increased significantly. The color change of MTA immersed in blood was measured on a spectrophotometer with a greater 7-day ∆E (21.257 ± 0.955) than the Biodentine 7-day ∆E (5.833 ± 0.501) (t=24.781, P < 0.001). MTA exhibits more discoloration as the immersion time goes on. A significant difference was noted between the 1-day ∆E(6.233 ± 0.888) and the 7-day ∆E(t=19.956, P < 0.001) of MTA immersed in blood. However, there was no statistically significant difference between the 1-day ∆E (6.790 ± 0.831) and the 7-day ∆E(t=1.707, P=0.163) of Biodentine immersed in blood. It was observed by scanning electron microscopy that after 7 days of immersion in the defibrinated sheep ablood, the surface porosity of MTA was larger than that of Biodentine, and the crystal edge of MTA became rounded and blunt. The analysis by energy-dispersive X-ray spectroscopy showed that the oxygen content decreased and the bismuth content increased in MTA after immersion in defibrinated sheep blood for 7 days. Zirconium was not detected in Biodentine due to its low radiodensity, but the contents of other elements were stable in Biodentine after immersion in defibrinated sheep blood for 7 days. @* Conclusion@#The color stability of Biodentine within the blood environment is better than that of MTA in vitro, which is mainly related to the low surface porosity and stable composition of the anti-radiation agent of Biodentine.