A new type of artificial saliva, delivered as a mouthwash and made using a lab-modified sugarcane protein called CANECPI-5, could help protect the teeth of patients with head and neck cancer. These patients often undergo radiotherapy near the mouth, which can damage salivary glands and reduce saliva production. Because saliva plays a key role in controlling bacteria and maintaining oral health, its loss can lead to serious dental problems.
Researchers at the Bauru School of Dentistry at the University of São Paulo (FOB-USP) in Brazil found that CANECPI-5 creates a protective “shield” over teeth. This layer helps defend enamel from acids found in beverages like juice and alcohol, as well as acids from the stomach. The findings were published in the Journal of Dentistry.
International Research Collaboration and Study Design
The research was carried out during the doctoral work of Natara Dias Gomes da Silva at FOB-USP. The project included collaboration with scientists from the Federal University of São Carlos (UFSCar) in Brazil, the University of California in San Francisco in the United States, and Yonsei University College of Dentistry in South Korea.
The study is part of the Thematic Project “Modulation of acquired pellicle to control dental mineral loss: unveiling mechanisms to make therapies possible,” coordinated by Professor Marília Afonso Rabelo Buzalaf at FOB-USP.
“We tested the mouthwash developed with CANECPI-5 by applying this solution to small pieces of animal teeth once a day for one minute. Based on these results, we’ll conduct further research so that we can think about applications of this product,” adds Silva, the first author of the article.
How Artificial Saliva Strengthens Tooth Enamel
“This is the first product that uses the concept of acquired pellicle [a thin protective layer that quickly forms on the tooth surface] to treat xerostomia, which is the sensation of a dry mouth caused by a lack of saliva. We use substances that will reformulate the composition of the proteins that bind to the teeth,” explains Buzalaf.
“We’ve developed a process in which CANECPI-5 binds directly to tooth enamel, helping to make teeth more resistant to the action of acids produced by bacteria,” Silva points out.
The study showed that CANECPI-5 works best when combined with fluoride and xylitol. In testing, the artificial saliva spray reduced bacterial activity and slowed tooth demineralization — the process by which teeth lose calcium and phosphate, making them more vulnerable to cavities.
A Potential Solution for Severe Cavities After Cancer Treatment
This development is especially important because there is currently no dedicated product available to treat the severe cavities that often occur after radiation therapy for head and neck cancer.
“Artificial saliva improves the sensation of dry mouth and sores. This helps with discomfort and also combats bacteria. In some cases, the use of this type of product is only for a short time. In others, it’s permanent, because many individuals lose the ability to produce saliva,” adds Buzalaf.
The CANECPI-5 protein has already been patented. The next step is to scale up production by partnering with companies interested in bringing the technology to market.
“We’ve already tested the solution as a mouthwash, gel, and orodispersible film, which is a type of plastic that’s placed on the tongue and dissolves, releasing the protein. We’ve tested it in several vehicles and found that CANECPI-5 works very well in all of them. We’ll continue testing other technologies within the Thematic Project to use not only this protein, but others as well,” says Buzalaf.
The Discovery of CANECPI-5 From Sugarcane Research
According to Flávio Henrique Silva, a professor in the Department of Genetics and Evolution at UFSCar who helped develop CANECPI-5, the work stems from earlier research on cystatins (a family of proteins involved in various biological processes) conducted as part of the Sugarcane Genome Project (SUCEST, FAPESP).
“At that time, our group identified and produced, in a recombinant form in bacteria, the first cystatin from sugarcane. We named it CANECPI-1. We then identified and produced five other cane cystatins, including CANECPI-5, which had potent inhibitory activities against cysteine peptidases, which are its target enzymes. Throughout our work, we noticed that this protein bound strongly to smooth surfaces, such as the quartz cuvettes used in activity measurements. This led us to conduct tests in partnership with Professor Marília Buzalaf on the binding of the protein to tooth enamel.”
Researchers say CANECPI-5 is especially promising because it both protects enamel and helps regulate oral bacteria, making it valuable for future dental treatments.
“CANECPI-5 has also been used in the work of other colleagues in the field of dentistry, particularly involving periodontitis. We also have a collaborative project with a colleague from the Federal University of Uberlândia, using subcutaneous sponge implants in mice, which has shown that it’s capable of reducing inflammation and promoting angiogenesis [the formation of new blood vessels] and fibrinogenesis [the formation of fibrin, a protein essential for blood clotting], important processes in tissue repair, making it a candidate molecule for use in wound healing,” Silva points out.
Next Steps for Artificial Saliva and Dental Applications
Within the Thematic Project, researchers will continue exploring how CANECPI-5 interacts with other compounds.
According to Buzalaf, one direction is to combine CANECPI-5 with a peptide derived from statherin, a protein found in saliva, to determine whether this hybrid could better protect teeth from acids originating in the stomach. Another goal is to investigate its potential role in preventing periodontal disease.
“Another aspect of the Thematic Project is to associate CANECPI-5 with vitamin E because this vitamin acts as a carrier, bringing the protein into contact with the tooth. We imagine that this could facilitate the application of the product directly by the patient at home,” says the researcher.
