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Microneedles can increase the effectiveness of topical anesthesia used in dentistry

Method aims at ensuring anesthesic substances a deeper penetration inside the mucosa; in tests, patients showed greater tolerance to pain derived from injected anestesia.

Fundação de Amparo à Pesquisa do Estado de São Paulo


IMAGE: This is Harvinder Gill, professor in the Department of Chemical Engineering at Texas Tech University view more 

Credit: Karina Toledo / Agência FAPESP

Researchers from Brazil and Texas have started testing on humans a new strategy to increase the effectiveness of topical anesthesia used in dentistry, used by dentists to reduce patient discomfort during the application of injected anesthesia - required for more invasive procedures such as fillings, tooth extraction or surgery.

It involves a small device that contains 57 microneedles, which, when placed on the gums, cheek or other location of the mouth to be anesthetized, makes tiny holes through which anesthetic substances like lidocaine can penetrate deeper into regions of the oral mucosa.

The fear of the injection is one of the main reasons that cause patients to develop dental phobia and avoid dental treatments, which negatively impacts the population's oral health, ponders Harvinder Gill - a professor in the Department of Chemical Engineering at Texas Tech University (TTU), Gills develops a Project in partnership with researcher Michele Leite, of the Piracicaba School of Dentistry (FOP), at the University of Campinas (UNICAMP) in São Paulo, Brazil, under the scope of São Paulo Researchers in International Collaboration (SPRINT) program, coordinated by the São Paulo Research Foundation - FAPESP, responsible for funding the Project.

"That situation causes anxiety for patients and dentists alike, and could compromise the treatment outcome," Gill said. According to him, because they have little penetration and are not very effective, conventional methods of topical anesthesia cannot completely assure protection for the patient. "A deep injection is needed to numb the area to be treated or block a nerve. And this injection is usually painful."

The method had already been tested on 10 patients in a preliminary test and according to Gill, it was well-tolerated.

"Included among our objectives is measuring the pain caused by the 700 micrometer-length microneedles, as well as determining the effectiveness of this system in expanding the action of the topical anesthesia," said the researcher. One of the project's main goals is evaluating the feasibility of this new strategy for releasing drugs into the oral mucosa.

The topic was highlighted during FAPESP Week Nebraska-Texas, held on September 18-22 in the cities of Lincoln, Nebraska and Lubbock, Texas, with the aim of fostering collaborative research between São Paulo e United States scientists.

Planting the seeds of international partnerships

The Symposium in Lubbock set the stage for other international collaborations under the SPRINT scope - that is, projects among FAPESP-funded researchers and scientists from the Foundation's many partners abroad, whose initial phase received the funding needed to sustain its development in the medium- and long-term.

One of such projects is the study led by Sonia Marli Zingaretti, of the University of Ribeirão Preto (Unaerp), in the State of São Paulo, and Kameswara Rao Kottapalli, of the Center for Biotechnology and Genomics at TTU. The objective of the pair is to identify genetic variables that make certain sugarcane cultivars more tolerant to stress caused by the presence of aluminum in the soil.

"Sugarcane plantations are widespread throughout Brazil, including in the Cerrado savannah, where the soil has a lot of aluminum. These molecules are toxic to the plant because they interfere with root development and reduce productivity," Zingaretti explained.

The group selected cultivars considered to be more or less tolerant to that type of stress and sequenced all the plants' RNA and microRNA molecules that were being expressed. Now the researchers are conducting analyses to identify which genes are essential to protecting the plant from, or making it susceptible to, stress.

Another collaborative project presented at the event focuses on studying what, if any, impact the interaction between endocrine disrupters (substances capable of interfering in the action of various hormones important to the organism) and global warming has on the reproductive health of fish.

The study is led by Ricardo Hattori, of the São Paulo Agency for Agribusiness Technology (APTA), in the State of São Paulo, and Reynaldo Patiño, of the Department of Natural Resources Management at TTU.

"We already know that changes in water temperature can cause a change in the sex of fish. Warming, for example, can lead to conversion of an animal of the female sex into a male. Moreover, various aquatic systems are already full of contaminants with action similar to sex hormones, which can also have an influence on determining the sex of the fish," Hattori explained.

According to the APTA scientist, it is still unclear what the combination of these two factors (endocrine disrupters and global warming) can cause in the animals. It is possible that one promotes the action of the other, or that one inhibits the action of the other. This is what the project is attempting to understand.

The social insects that belong to the family Membracidae, which take unusual forms, are the subject of the project led by Monica Tallarico Pupo, of the School of Pharmaceutical Sciences of Ribeirão Preto (FCFRP), at the University of São Paulo (USP), and by Amanda Brown, of the Department of Biological Sciences at TTU. The study seeks to understand the complex system of microorganisms that live symbiotically with these invertebrates, which have up to six distinct bacteria and intracellular fungi that interact and provide key metabolic functions to the host.

According to Pupo, the ultimate goal is to identify potential new therapeutic agents for diseases that affect humans.

Professor Chris Rock, of the Department of Biological Sciences at TTU presented his project conducted in collaboration with Ivan de Godoy Maia, of São Paulo State University (Unesp) in Botucatu, in the State of São Paulo. They are investigating the genes involved in the production of bioactive compounds such as anthocyanins in plants.

Andrea Jackowski, of the Federal University of São Paulo (Unifesp) and her colleagues at TTU, presented the collaborative project aimed at studying the effects of toxic stress on the neurodevelopment, cognition and socioemotional aspects of children and adolescents in Brazil and the United States (more information available at:

For their part, Naima Moustaid-Moussa, of the Obesity Research Cluster at TTU, and Theresa Ramalho, of the Biomedical Sciences Institute of the University of São Paulo (ICB-USP), talked about a study that seeks to understand the mechanisms through which omega-3 fatty acids protect laboratory animals, subjected to high fat diets, against the development of metabolic and inflammatory disorders. The study is also led by ICB-USP Professor Sônia Jancar.


About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. For more information:

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