Dentinal tubules driven wetting of dentin: Cassie-Baxter modelling

• Published in: The European physical journal. E, Soft matter and biological physics Vol. 30; no. 2; pp. 187 - 195
• Main Authors: Ramos, S. M. M., Alderete, L., Farge, P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-10-2009; EDP Sciences
• Subjects: Biological and Medical Physics; Biological and medical sciences; Biophysics; Chemistry; Complex Fluids and Microfluidics; Complex Systems; Dental Bonding - methods; Dentin - chemistry; Dentin - ultrastructure; Dentin-Bonding Agents - chemistry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General and physical chemistry; Humans; Hydroxyapatites - chemical synthesis; Hydroxyapatites - chemistry; Microscopy, Atomic Force - methods; Models, Biological; Molecular biophysics; Nanotechnology; Physics; Physics and Astronomy; Polymer Sciences; Regular Article; Soft and Granular Matter; Surface physical chemistry; Surface Properties; Surface properties. Adsorption; Surfaces and Interfaces; Thin Films; Water - chemistry; Wettability; 68.35.Ct Interface structure and roughness; 61.30.Hn Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions; 87.85.jf Bio-based materials; 68.08.Bc Wetting; Water; Measurement; Atomic force microscopy; Wetting; Methodology; Roughness; Hydroxyapatite; Etching; Properties; Inorganic element; Topography; Procedure; Chemical composition; Ratio; Exposure time; Adhesive; Phosphoric acid; Heterogeneous surface; Air drying; Sample; Increase; Air; Contact angle; Rough surface; Experimental result; Drying
• ISSN: 1292-8941; 1292-895X
• DOI: 10.1140/epje/i2008-10444-x

We investigate the wetting properties of dentin surfaces submitted to a phosphoric acid etching followed by an air drying procedure, as in clinical situations of adhesive dentistry. The surface topography of the etched surfaces was characterized by AFM, and the wetting properties of water on these rough and heterogeneous surfaces were studied, by contact angle measurements. We showed that the contact angle increases with the acid exposure time and consequently with both surface roughness and the organic-mineral ratio of the dentin components. From the whole results, obtained on dentin and also on synthesized hydroxyapatites samples, we inferred a water contact angle of ∼ 133
°
on the dentinal tubule. These experimental results may be described by the
Cassie-Baxter approach
, and it is suggested that small air pockets could be formed inside the dentinal tubules.