Volume 9 • 2022 • Issue 3

Dr. Siqueira has a hypothesis that in the animal kingdom the complexity of saliva is inversely correlated to the number of times a creature replaces its teeth over a lifespan. For instance, a shark replaces its teeth frequently, so it doesn’t require complex saliva. Indeed, shark saliva seems to have mucins, a big protein that protects the soft skin inside the shark’s mouth from seawater that constantly flows through it. “And not much else,” says Dr. Siqueira. “But humans, who only gets two sets of teeth in a lifetime, needed to evolve complex saliva that can fight bacteria and repair teeth because teeth are the only parts of the body that can’t heal themselves.” In the dental clinic, Dr. Siqueira noticed that saliva was primarily seen as a nuisance during restorations. “Often we were trying to avoid it and make sure it didn’t contaminate our work,” he says. But he feels that in the future, saliva will become more valued by dentists, especially as a diagnostic tool. “Just like physicians have blood to help diagnose disease, we’ll have saliva,” he says. He hopes that measuring the volume of saliva will become a routine part of dental examinations. And as health care becomes more personalized, testing saliva for certain proteins could become a key part of how dentists care for patients. Dr. Siqueira is a true advocate for saliva and he believes that learning more about how saliva works has the potential to improve the oral health of millions of people. “Saliva helps keep mouths healthy, so it’s on the same team as dentists. We’re fighting the same fight!” he says. References: 1. OppenheimFG, Salih E, SiqueiraWL, ZhangW, Helmerhorst EJ. Salivary proteome and its genetic polymorphisms. AnnNYAcad Sci . 2007;1098:22-50. 2. SiqueiraWL, CustodioW, McDonald EE. New insights into the composition and functions of the acquired enamel pellicle. J Dent Res . 2012;91(12):1110-8. 3. Isho B, Abe KT, ZuoM, Jamal AJ, Bhavisha R,Wang JH, et al. Persistence of serum and saliva antibody responses to SARS-CoV-2 spike antigens inCOVID-19 patients. Sci Immunol . 2020 8;5(52):eabe5511. 4. Zhu Y, Marin LM, Xiao Y, Gillies ER, SiqueiraWL. pH-Sensitive ChitosanNanoparticles for Salivary ProteinDelivery. Nanomaterials (Basel) . 2021;11(4):1028. After finishing his dental degree, Dr. Walter Siqueira earned a PhD in Oral Biology and Biochemistry at the Universidade de São Paulo in 2005. He taught at Boston University and Western University before becoming a professor at the University of Saskatchewan, where he currently serves as associate dean of the College of Dentistry. In 2012, Dr. Siqueira was the recipient of the Salivary Researcher of the Year award by the Salivary Research Group of the International Association for Dental Research (IADR). He went on to receive the 2019 IADR Distinguished Scientist Award. Dr. Siqueira served as president of the Canadian Association for Dental Research (CADR) from 2019–21. In September 2021, Dr. Siqueira was inducted as a fellow into the Canadian Academy of Health Sciences, one of the highest honours granted to scholars in Canada. 38 | 2022 | Issue 3 Issues and People