Hydroxyapatite pellets as versatile model surfaces for systematic studies on enamel

Abstract

Research into materials for medical application draws inspiration from naturally occurring or synthesized surfaces, just like many other research directions. For medical application of materials, particular attention has to be paid to biocompatibility, osseointegration and bacterial adhesion behavior. To understand their properties and behavior, experimental studies with natural materials such as teeth are strongly required. The results, however, may be highly case-dependent because natural surfaces have the disadvantage of being subject to wide variations, for instance in their chemical composition, structure, morphology, roughness, and porosity. A synthetic surface which mimics enamel in its performance with respect to bacterial adhesion and biocompatibility would, therefore, facilitate systematic studies much better. In this study, we discuss the possibility of using hydroxyapatite (HAp) pellets to simulate the surfaces of teeth and show the possibility and limitations of using a model surface. We performed single-cell force spectroscopy with single Staphylococcus aureus cells to measure adhesion-related parameters such as adhesion force and rupture length of adhesins binding to HAp and enamel. We also examine the influence of blood plasma and saliva on the adhesion properties of S. aureus. The results of these measurements are matched to water wettability, elemental composition of the samples and the change in the macromolecules adsorbed over time. We found that the adhesion properties of S. aureus were similar on both samples under all conditions: Significant decreases in adhesion strength were found equally in the presence of saliva or blood plasma on both surfaces. We therefore conclude that HAp pellets are a good alternative for natural dental material. This is especially true when slight variations in the physicochemical properties of the natural materials may affect the experimental series.

Quantification of the Adhesion Strength of Candida albicans to Tooth Enamel

“…It has been suggested that C. albicans does not bind some salivary ligands (e.g., PRPs), when these are in solution, which has been shown for the oral bacterium Streptococcus gordonii [42,45]. It cannot be excluded, however, that the newly yeast cell surface-attached salivary components might mediate the adhesion to the pellicle as well, as has been suggested for saliva-coated S. aureus bacterial cells on saliva-treated titanium [31].…”

“…The FluidFM combines an atomic force microscope (AFM) cantilever with a microfluidic channel that can be used to immobilize single cells at the free end of the cantilever [25,27,29]. Additionally, AFM-based SCFS allows to quantify the adhesion of microbial cells covered with bodily fluids, like saliva or blood plasma [27,28,30,31].…”

Hydroxyapatite Film Coating by Er:YAG Pulsed Laser Deposition Method for the Repair of Enamel Defects

“…Generally, HAp is an ideal material for dental restorations, as it is the constituent material of the tooth substance [ 19 , 28 ]. It is extremely difficult to develop an artificial HAp enamel for the teeth owing to the difference in roughness.…”