Electronic Thesis and Dissertation Repository


Master of Engineering Science


Biomedical Engineering


Dr. Walter Siqueira



Saliva is responsible for the formation of the acquired enamel pellicle (AEP), a protein

integument formed as a result of selective adsorption of salivary proteins to the enamel

surface. The AEP demonstrates an important role for modulating dental erosion as a

result of its physical properties, along with its salivary and exogenous protein

composition (Chapter 2). In addition, individual proteins that comprise the AEP have

important physiological functions. Histatin 5 (H5) has potent antifungal effect against C.

albicans, the yeast responsible for the initiation of oral candidiasis. We designed an in

vitro model and found, for the first time, that H5 adhered in the form of pellicle retains its

antifungal activity on C. albicans (Chapter 3). As a pellicle precursor protein, H5

demonstrates high affinity for hydroxyapatite, the primary mineral component of enamel.

We used atomic force microscopy (AFM) to determine adhesion forces between H5 and

the hydroxyapatite surface to be stronger compared to our protein control, albumin. This

knowledge can be applied in the design of therapeutic proteins, and the methodology that

we developed can be used for measuring adhesion forces between various other proteins

and substrates of interest (Chapter 4). Finally, with the development of proteomics

instruments, researchers have identified some protein biomarkers, hidden within salivary

fluids. These can be used for diagnostic dentistry, in a clinical setting to identify patients’

susceptibility of developing oral diseases. In addition, the delivery proteins with

antimicrobial properties via toothpastes or oral rinses can have tremendous therapeutic

potential for a multitude of oral diseases (Chapter 5).