Real-Time Evaluation of the Thickness and Viscoelastic Properties of the Salivary Pellicle in Oral and Oropharyngeal Cancer Patients treated with Radiotherapy

• Grant number: 24/17375-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Social and Preventive Dentistry
• Principal Investigator: Talita Mendes Oliveira Ventura
• Grantee: Tiago Mello Scherrer
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Cancer is one of the leading causes of mortality worldwide, and it is currently a major public health issue. The acquired enamel pellicle (AEP) is a film formed in vivo as a result of the selective adsorption of salivary proteins onto the surface of the tooth, which also contains glycoproteins and lipids. The presence of proteins in the AEP forms a protective interface over the tooth surface, participating in all interfacial events that occur in the oral cavity. Research has focused on the characterization and protective impact of the acquired pellicle formed on the enamel surface. However, the number of studies in the literature using molecular interaction tools is still small when related to the formation and protection of the AEP in oncology patients with oral cancer (OC) and oropharyngeal cancer (OPC) undergoing radiotherapy. Additionally, little is known about the conditions of thickness and viscoelasticity of the AEP in these patients. Based on this, the aim of this study is to evaluate the changes in thickness and viscoelastic properties of the AEP in patients with OC and OPC. The research will involve 18 participants, aged 18 years or older, including 9 individuals without a diagnosis of OC and OPC, non-smokers, in good general and oral health, and 9 diagnosed with OC and OPC undergoing radiotherapy. Unstimulated saliva will be collected in the morning at different time points during the oncological treatment (before and during radiotherapy, in addition to the control group). Real-time analysis of the AEP will be performed using a quartz crystal microbalance with dissipation monitoring (QCM-D). For this, a Q-Sense E4 system with hydroxyapatite sensors (QSX 999 HA) will be used. Saliva samples from the patients at different treatment stages (before and during radiotherapy), as well as the control group, will be included in biological triplicates according to the treatment periods and will be added to the hydroxyapatite sensor cell. The D-find software will be used to numerically adjust the changes measured in resonance frequency and energy dissipation to obtain the thickness, elastic modulus, and viscosity of the AEP. This translational approach aims to enhance our understanding of the dynamics of the AEP in patients with OC and OPC undergoing radiotherapy and to understand the changes caused by treatment related to the oral protection of these patients.