Watch the full conversation with Dr. Desai on CDA Oasis: bit.ly/3MtQLGn structure, removing the need to drill. These low-viscosity resins bond on the tooth structure after penetration and form a barrier that prevents further loss of minerals (demineralization), leading to caries arrest.” When the scope of application for low viscosity resin was widened to include larger lesions, efficacy of caries arrest began to fall. “There are inherent shortcomings with these resin materials. They create a barrier, however, in larger lesions these barriers do not effectively isolate the carious lesions from the oral environment. Therefore, some bacteria that remain trapped within the lesion may continue to thrive, resulting in caries progression,” she says. “As well, these resins tend to degrade over time because of the enzymes from the bacteria and in saliva.” In the lab, Dr. Desai and her team, which includes Dr. Cameron Stewart and faculty member Dr. Yoav Finer, are working on modifying previously designed silicon mesoporous nanoparticles, which have pores where an antimicrobial drug can be stabilized, to optimize drug release. “As the nanoparticle absorbs water from the oral environment, the pores will swell and release the drug, slowly over time, in a controlled manner,” she says. “Because the nanoparticle is porous, we can incorporate a lot of the drug into it, and, theoretically, it could be released slowly over 30 years.” Of course, the low viscosity antimicrobial resin is still a work in progress. “We’ve found that we can make a resin with 10% nanoparticles without substantially altering its physical properties,” she says. “And we’ve found that over 90 days in the mouth, about 10% of the antimicrobial drugs were released, which is promising. Now we need to test its effectiveness in inhibiting bacterial growth to see what this formulation will do to biofilm,” says Dr. Desai. If the newmaterial is proven to be effective in preventing bacterial growth in larger lesions, she believes it might be something that can be added to resin materials and used to treat caries without drilling. “A drill-free treatment could foster a more positive relationship with dental care for children that would last a lifetime,” Dr. Desai says. Dr. Desai also notes that the high efficacy of low viscosity resin for white spots may also be related to the spots usually being located on front teeth. “Front teeth tend to be brushed well, whereas in the back of the mouth, brushing is more of a problem,” she says. How can these problems with low viscosity resin be solved so that applying it directly to a carious lesion is an effective treatment? “The properties of the material need to be modified so that it doesn’t facilitate bacterial growth,” says Dr. Desai. “So, if the material itself had antimicrobial properties, that would be fantastic. And we need to figure out how to prevent it from breaking down so we can increase the lifespan of restorations.” Dr. Desai and her research team at U of T began to utilize newly developed low-viscosity, biostable resins that are less susceptible to degradation and to add technology with antimicrobial effects. “We’re using nanoparticles to deliver antimicrobial drugs to the tooth structure,” she says. “Just adding an antimicrobial agent directly to the resin appears to interfere with viscosity and the antimicrobial agent is often only released from the resin for a limited amount of time, only for a few days.” Just adding an antimicrobial agent directly to the resin appears to interfere with viscosity and the antimicrobial agent is often only released from the resin for a limited amount of time, only for a few days. As the nanoparticle absorbs water from the oral environment, the pores will swell and release the drug, slowly over time, in a controlled manner. 20 | 2023 | Issue 6 Issues and People
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